* [PATCH v1] serial: qcom-geni: Avoid probing debug console UART without console support
From: Aniket Randive @ 2026-04-13 7:25 UTC (permalink / raw)
To: gregkh, jirislaby, linux-arm-msm, linux-kernel, linux-serial,
praveen.talari, anup.kulkarni, dmitry.baryshkov, viken.dadhaniya
Cc: Aniket Randive
When CONFIG_SERIAL_QCOM_GENI_CONSOLE is disabled, the driver still
advertises the debug UART compatible strings ("qcom,geni-debug-uart"
and "qcom,sa8255p-geni-debug-uart") in its of_match table. This lets the
driver match and probe console UART DT nodes even though console
support is not built. As a result, the console port is never registered
with the UART core and uart_add_one_port() fails with -EINVAL.
Fix this by only including the debug UART compatible entries in the
match table when CONFIG_SERIAL_QCOM_GENI_CONSOLE is enabled, preventing
the driver from probing console UART nodes when console support is
absent.
Signed-off-by: Aniket Randive <aniket.randive@oss.qualcomm.com>
---
drivers/tty/serial/qcom_geni_serial.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 9854bb2406e3..b756e0c07c16 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -2039,6 +2039,7 @@ static const struct dev_pm_ops qcom_geni_serial_pm_ops = {
};
static const struct of_device_id qcom_geni_serial_match_table[] = {
+#if IS_ENABLED(CONFIG_SERIAL_QCOM_GENI_CONSOLE)
{
.compatible = "qcom,geni-debug-uart",
.data = &qcom_geni_console_data,
@@ -2047,6 +2048,7 @@ static const struct of_device_id qcom_geni_serial_match_table[] = {
.compatible = "qcom,sa8255p-geni-debug-uart",
.data = &sa8255p_qcom_geni_console_data,
},
+#endif
{
.compatible = "qcom,geni-uart",
.data = &qcom_geni_uart_data,
--
2.34.1
^ permalink raw reply related
* [PATCH v1] serial: sh-sci: fix memory region release in error path
From: zenghongling @ 2026-04-13 4:08 UTC (permalink / raw)
To: gregkh, jirislaby, geert+renesas, biju.das.jz, wsa+renesas,
thierry.bultel.yh, prabhakar.mahadev-lad.rj
Cc: linux-kernel, linux-serial, zhongling0719, Hongling Zeng,
kernel test robot, Dan Carpenter
From: Hongling Zeng <zenghongling@kylinos.cn>
The sci_request_port() function uses request_mem_region() to reserve
I/O memory, but in the error path when sci_remap_port() fails, it
incorrectly calls release_resource() instead of release_mem_region().
This mismatch can cause resource accounting issues. Fix it by using
the correct release function, consistent with sci_release_port().
Fixes: 2667bd6673eb ("serial: 8250_port: simplify serial8250_request_std_resource()")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Closes: https://lore.kernel.org/r/202604032356.SzEjYkBC-lkp@intel.com/
Signed-off-by: Hongling Zeng <zenghongling@kylinos.cn>
---
Change in v1:
- Fix the commit message and change name
---
---
drivers/tty/serial/sh-sci.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index bd7486315338..9e619db27237 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -3024,7 +3024,7 @@ int sci_request_port(struct uart_port *port)
ret = sci_remap_port(port);
if (unlikely(ret != 0)) {
- release_resource(res);
+ release_mem_region(port->mapbase, sport->reg_size);
return ret;
}
--
2.25.1
^ permalink raw reply related
* [PATCH v2 4/4] Revert "drivers: convert sbd_duart.map_guard from atomic_t to refcount_t"
From: Maciej W. Rozycki @ 2026-04-13 4:03 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: Elena Reshetova, David Windsor, Kees Cook, Hans Liljestrand,
linux-mips, linux-serial, linux-kernel
In-Reply-To: <alpine.DEB.2.21.2604130453400.29980@angie.orcam.me.uk>
Revert commit 22a33651a56f ("drivers: convert sbd_duart.map_guard from
atomic_t to refcount_t"), which broke perfectly valid code:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 1 at lib/refcount.c:114 sbd_request_port+0x54/0x140
refcount_t: increment on 0; use-after-free.
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc2+ #34
Stack : 0000000014001fe0 0000000000000000 ffffffff80830000 0000000000000000
ffffffff8127bc7a ffffffff8016fe08 ffffffff808d0000 ffffffff808d0000
ffffffff807aa828 ffffffff80822337 ffffffff808ce188 a8000001860b0000
0000000000000001 0000000000000001 00000000000001c8 ffffffff808a3090
00000000000000bb ffffffff801b09d4 a80000018609bb68 ffffffff801231cc
ffffffff812a0000 ffffffff80171388 0000000000001000 ffffffff807aa828
0000000000000001 0000000000000001 0000000000000000 0000000000000000
0000000000000000 a80000018609bab0 0000000000000000 ffffffff803c47cc
0000000000000000 0000000000000000 0000000000000000 0000000000000000
ffffffff807cb648 ffffffff8010bff8 0000000014001fe1 ffffffff803c47cc
...
Call Trace:
[<ffffffff8010bff8>] show_stack+0x28/0x88
[<ffffffff803c47cc>] dump_stack+0x8c/0xc0
[<ffffffff801aff5c>] __warn+0xe0/0x114
[<ffffffff801233f0>] warn_slowpath_fmt+0x40/0x50
[<ffffffff80455bcc>] sbd_request_port+0x54/0x140
[<ffffffff804563a4>] sbd_config_port+0x2c/0x68
---[ end trace f666d696412caa3e ]---
(report at the offending commit) -- sbd_request_port() is called twice
per DUART instance, to reserve a resource holding the control register
block shared between the two channels, so there's no slightest chance
for an overflow. Also this doesn't stop the driver from working and
it's just the reservation that is missing as a result, i.e.:
10060100-100601ff : sb1250-duart
10060200-100602ff : sb1250-duart
as from the offending change, vs:
10060100-100601ff : sb1250-duart
10060200-100602ff : sb1250-duart
10060300-100603ff : sb1250-duart
beforehand, which is surely why the breakage has gone so long unnoticed.
"If it ain't broke, don't fix it," so just revert the broken commit.
Fixes: 22a33651a56f ("drivers: convert sbd_duart.map_guard from atomic_t to refcount_t")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
---
No change from v1.
---
drivers/tty/serial/sb1250-duart.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
linux-serial-sb1250-duart-map-guard-atomic.diff
Index: linux-macro/drivers/tty/serial/sb1250-duart.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/sb1250-duart.c
+++ linux-macro/drivers/tty/serial/sb1250-duart.c
@@ -34,8 +34,8 @@
#include <linux/tty_flip.h>
#include <linux/types.h>
-#include <linux/refcount.h>
-#include <linux/io.h>
+#include <linux/atomic.h>
+#include <asm/io.h>
#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_uart.h>
@@ -86,7 +86,7 @@ struct sbd_port {
struct sbd_duart {
struct sbd_port sport[2];
unsigned long mapctrl;
- refcount_t map_guard;
+ atomic_t map_guard;
};
#define to_sport(uport) container_of(uport, struct sbd_port, port)
@@ -662,13 +662,15 @@ static void sbd_release_port(struct uart
{
struct sbd_port *sport = to_sport(uport);
struct sbd_duart *duart = sport->duart;
+ int map_guard;
iounmap(sport->memctrl);
sport->memctrl = NULL;
iounmap(uport->membase);
uport->membase = NULL;
- if(refcount_dec_and_test(&duart->map_guard))
+ map_guard = atomic_add_return(-1, &duart->map_guard);
+ if (!map_guard)
release_mem_region(duart->mapctrl, DUART_CHANREG_SPACING);
release_mem_region(uport->mapbase, DUART_CHANREG_SPACING);
}
@@ -704,6 +706,7 @@ static int sbd_request_port(struct uart_
{
const char *err = KERN_ERR "sbd: Unable to reserve MMIO resource\n";
struct sbd_duart *duart = to_sport(uport)->duart;
+ int map_guard;
int ret = 0;
if (!request_mem_region(uport->mapbase, DUART_CHANREG_SPACING,
@@ -711,11 +714,11 @@ static int sbd_request_port(struct uart_
printk(err);
return -EBUSY;
}
- refcount_inc(&duart->map_guard);
- if (refcount_read(&duart->map_guard) == 1) {
+ map_guard = atomic_add_return(1, &duart->map_guard);
+ if (map_guard == 1) {
if (!request_mem_region(duart->mapctrl, DUART_CHANREG_SPACING,
"sb1250-duart")) {
- refcount_dec(&duart->map_guard);
+ atomic_add(-1, &duart->map_guard);
printk(err);
ret = -EBUSY;
}
@@ -723,7 +726,8 @@ static int sbd_request_port(struct uart_
if (!ret) {
ret = sbd_map_port(uport);
if (ret) {
- if (refcount_dec_and_test(&duart->map_guard))
+ map_guard = atomic_add_return(-1, &duart->map_guard);
+ if (!map_guard)
release_mem_region(duart->mapctrl,
DUART_CHANREG_SPACING);
}
^ permalink raw reply
* [PATCH v2 3/4] MIPS: SiByte: Convert to use a platform device
From: Maciej W. Rozycki @ 2026-04-13 4:03 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: Elena Reshetova, David Windsor, Kees Cook, Hans Liljestrand,
linux-mips, linux-serial, linux-kernel
In-Reply-To: <alpine.DEB.2.21.2604130453400.29980@angie.orcam.me.uk>
Prevent a crash from happening as the first serial port is initialised:
pata-swarm: PATA interface at GenBus slot 4
workingset: timestamp_bits=62 max_order=18 bucket_order=0
Block layer SCSI generic (bsg) driver version 0.4 loaded (major 253)
CPU 1 Unable to handle kernel paging request at virtual address 0000000000000208, epc == ffffffff8067f8f8, ra == ffffffff80666330
Oops[#1]:
CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.19.0-dirty #27 NONE
$ 0 : 0000000000000000 0000000014001fe0 0000000000000020 ffffffff80666130
$ 4 : 0000000000000000 a800000100e6f118 ffffffff8112cbc0 0000000000000000
$ 8 : 0000000000000002 0000000000000000 0000000000000000 0000000001a80000
$12 : 0000000000000000 ffffffff809fd488 000000004ddf14dd ffffffff00000000
$16 : a800000100e6f000 0000000000000000 ffffffff8112c1d0 a800000100e6f000
$20 : 0000000000000000 00000000000004d0 0000000000000004 ffffffff8112c1d0
$24 : 0000000000000001 0000000000000003
$28 : a80000010007c000 a80000010007fcb0 00000000000000ef ffffffff80666330
Hi : fffffffffffffdb9
Lo : 0000000000000035
epc : ffffffff8067f8f8 __dev_fwnode+0x0/0x8
ra : ffffffff80666330 serial_base_ctrl_add+0xb8/0x180
Status: 14001fe3 KX SX UX KERNEL EXL IE
Cause : 80800008 (ExcCode 02)
BadVA : 0000000000000208
PrId : 03040102 (SiByte SB1)
Process swapper/0 (pid: 1, threadinfo=(____ptrval____), task=(____ptrval____), tls=0000000000000000)
Stack : 0000000000000000 ffffffff80cd5178 ffffffff80cd0000 ffffffff8112c1c8
0000000000000260 ffffffff806655c4 a800000100275bc0 ffffffff8064ac88
004000408112c000 0000000000000002 0000000000000000 ffffffff801965d0
a800000100786ba0 ffffffff80cd5178 a800000100786ba0 0000000000000004
a800000100275bc0 0000000000000000 0000000000000000 ffffffff80cd5178
0000000000000000 ffffffff8112c1c8 0000000000000260 00000000000004d0
0000000000000004 ffffffff80bf0000 00000000000000ef ffffffff80d171dc
ffffffff80d17120 ffffffff80d25658 0000000000000000 ffffffff80d50000
ffffffff80d2f928 ffffffff80d50000 ffffffff80d25698 ffffffff80cfcecc
00ffffff80b84428 0000000000000000 0000000000000006 0000000000000006
...
Call Trace:
[<ffffffff8067f8f8>] __dev_fwnode+0x0/0x8
[<ffffffff80666330>] serial_base_ctrl_add+0xb8/0x180
[<ffffffff806655c4>] serial_core_register_port+0x174/0x8e0
[<ffffffff80d171dc>] sbd_init+0xbc/0xf4
[<ffffffff80cfcecc>] do_one_initcall+0x64/0x150
[<ffffffff80cfd284>] kernel_init_freeable+0x25c/0x30c
[<ffffffff809ff6e4>] kernel_init+0x24/0x118
[<ffffffff80112d20>] ret_from_kernel_thread+0x14/0x1c
Code: 67bd0010 03e00008 2402ffea <03e00008> dc820208 67bdffa0 ffbe0050 ffb70048 ffb60040
---[ end trace 0000000000000000 ]---
-- where a pointer is dereferenced that has been derived from a null
pointer to the port's parent device.
Since no device is available with legacy probing and it's not anymore a
preferable way to discover devices anyway, switch the driver to using a
platform device and use it as the port's parent device.
Use platform_driver_probe() because SB1250 DUART devices are embedded
onchip the SoC and therefore not that straightforward to remove.
An unfortunate consequence of the switch to a platform device is we now
hand the console over from the bootconsole much later in the bootstrap.
The CFE console handler appears good enough though to work so late and
in particular with interrupts enabled.
Conversely only starting the console port so late lets the reset code
fully utilise our delay handlers, so switch from udelay() to fsleep()
for transmitter draining so as to avoid busy-waiting for an excessive
amount of time.
Since there is one way only remaining to reach sbd_init_port() now, drop
the port initialisation marker as no longer needed and go through the
channel resets unconditionally.
Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # needs to use .remove_new for <= 6.10
---
Changes from v1:
- Remove a stray `i' variable from sbd_probe().
---
arch/mips/sibyte/swarm/platform.c | 97 +++++++++++++++++++++++--
drivers/tty/serial/sb1250-duart.c | 147 +++++++++++++-------------------------
2 files changed, 145 insertions(+), 99 deletions(-)
linux-serial-sb1250-duart-platform.diff
Index: linux-macro/arch/mips/sibyte/swarm/platform.c
===================================================================
--- linux-macro.orig/arch/mips/sibyte/swarm/platform.c
+++ linux-macro/arch/mips/sibyte/swarm/platform.c
@@ -8,7 +8,13 @@
#include <asm/sibyte/board.h>
#include <asm/sibyte/sb1250_genbus.h>
+#if defined(CONFIG_SIBYTE_BCM1x80)
+#include <asm/sibyte/bcm1480_regs.h>
+#include <asm/sibyte/bcm1480_int.h>
+#else
#include <asm/sibyte/sb1250_regs.h>
+#include <asm/sibyte/sb1250_int.h>
+#endif
#if defined(CONFIG_SIBYTE_SWARM) || defined(CONFIG_SIBYTE_LITTLESUR)
@@ -85,6 +91,82 @@ device_initcall(swarm_pata_init);
#endif /* defined(CONFIG_SIBYTE_SWARM) || defined(CONFIG_SIBYTE_LITTLESUR) */
+#if defined(CONFIG_SIBYTE_BCM1x80)
+static struct resource sb1250_duart_resources[][2] = {
+ {
+ {
+ .name = "sb1250-duart0",
+ .flags = IORESOURCE_MEM,
+ .start = A_BCM1480_DUART0,
+ .end = (A_BCM1480_DUART0 +
+ 4 * BCM1480_DUART_CHANREG_SPACING - 1),
+ },
+ {
+ .name = "sb1250-duart0",
+ .flags = IORESOURCE_IRQ,
+ .start = K_BCM1480_INT_UART_0,
+ .end = K_BCM1480_INT_UART_1,
+ },
+ },
+ {
+ {
+ .name = "sb1250-duart1",
+ .flags = IORESOURCE_MEM,
+ .start = A_BCM1480_DUART1,
+ .end = (A_BCM1480_DUART1 +
+ 4 * BCM1480_DUART_CHANREG_SPACING - 1),
+ },
+ {
+ .name = "sb1250-duart1",
+ .flags = IORESOURCE_IRQ,
+ .start = K_BCM1480_INT_UART_2,
+ .end = K_BCM1480_INT_UART_3,
+ },
+ },
+};
+#else /* !defined(CONFIG_SIBYTE_BCM1x80) */
+static struct resource sb1250_duart_resources[][2] = {
+ {
+ {
+ .name = "sb1250-duart0",
+ .flags = IORESOURCE_MEM,
+ .start = A_DUART,
+ .end = A_DUART + 4 * DUART_CHANREG_SPACING - 1,
+ },
+ {
+ .name = "sb1250-duart0",
+ .flags = IORESOURCE_IRQ,
+ .start = K_INT_UART_0,
+ .end = K_INT_UART_1,
+ },
+ },
+};
+#endif /* !defined(CONFIG_SIBYTE_BCM1x80) */
+
+static struct platform_device sb1250_duart_device[] = {
+ {
+ .name = "sb1250-duart",
+ .id = 0,
+ .resource = sb1250_duart_resources[0],
+ .num_resources = ARRAY_SIZE(sb1250_duart_resources[0]),
+ },
+#if defined(CONFIG_SIBYTE_BCM1x80)
+ {
+ .name = "sb1250-duart",
+ .id = 1,
+ .resource = sb1250_duart_resources[1],
+ .num_resources = ARRAY_SIZE(sb1250_duart_resources[1]),
+ },
+#endif
+};
+
+static struct platform_device *sb1250_duart_devices[] __initdata = {
+ &sb1250_duart_device[0],
+#if defined(CONFIG_SIBYTE_BCM1x80)
+ &sb1250_duart_device[1],
+#endif
+};
+
#define sb1250_dev_struct(num) \
static struct resource sb1250_res##num = { \
.name = "SB1250 MAC " __stringify(num), \
@@ -113,28 +195,31 @@ static struct platform_device *sb1250_de
static int __init sb1250_device_init(void)
{
- int ret;
+ int ret1, ret2;
+
+ ret1 = platform_add_devices(sb1250_duart_devices,
+ ARRAY_SIZE(sb1250_duart_devices));
/* Set the number of available units based on the SOC type. */
switch (soc_type) {
case K_SYS_SOC_TYPE_BCM1250:
case K_SYS_SOC_TYPE_BCM1250_ALT:
- ret = platform_add_devices(sb1250_devs, 3);
+ ret2 = platform_add_devices(sb1250_devs, 3);
break;
case K_SYS_SOC_TYPE_BCM1120:
case K_SYS_SOC_TYPE_BCM1125:
case K_SYS_SOC_TYPE_BCM1125H:
case K_SYS_SOC_TYPE_BCM1250_ALT2: /* Hybrid */
- ret = platform_add_devices(sb1250_devs, 2);
+ ret2 = platform_add_devices(sb1250_devs, 2);
break;
case K_SYS_SOC_TYPE_BCM1x55:
case K_SYS_SOC_TYPE_BCM1x80:
- ret = platform_add_devices(sb1250_devs, 4);
+ ret2 = platform_add_devices(sb1250_devs, 4);
break;
default:
- ret = -ENODEV;
+ ret2 = 0;
break;
}
- return ret;
+ return ret1 ? ret1 : ret2;
}
device_initcall(sb1250_device_init);
Index: linux-macro/drivers/tty/serial/sb1250-duart.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/sb1250-duart.c
+++ linux-macro/drivers/tty/serial/sb1250-duart.c
@@ -3,7 +3,7 @@
* Support for the asynchronous serial interface (DUART) included
* in the BCM1250 and derived System-On-a-Chip (SOC) devices.
*
- * Copyright (c) 2007 Maciej W. Rozycki
+ * Copyright (c) 2007, 2026 Maciej W. Rozycki
*
* Derived from drivers/char/sb1250_duart.c for which the following
* copyright applies:
@@ -25,6 +25,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/major.h>
+#include <linux/platform_device.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/spinlock.h>
@@ -45,10 +46,6 @@
#include <asm/sibyte/bcm1480_regs.h>
#include <asm/sibyte/bcm1480_int.h>
-#define SBD_CHANREGS(line) A_BCM1480_DUART_CHANREG((line), 0)
-#define SBD_CTRLREGS(line) A_BCM1480_DUART_CTRLREG((line), 0)
-#define SBD_INT(line) (K_BCM1480_INT_UART_0 + (line))
-
#define DUART_CHANREG_SPACING BCM1480_DUART_CHANREG_SPACING
#define R_DUART_IMRREG(line) R_BCM1480_DUART_IMRREG(line)
@@ -59,10 +56,6 @@
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_int.h>
-#define SBD_CHANREGS(line) A_DUART_CHANREG((line), 0)
-#define SBD_CTRLREGS(line) A_DUART_CTRLREG(0)
-#define SBD_INT(line) (K_INT_UART_0 + (line))
-
#else
#error invalid SB1250 UART configuration
@@ -85,7 +78,6 @@ struct sbd_port {
struct uart_port port;
unsigned char __iomem *memctrl;
int tx_stopped;
- int initialised;
};
/*
@@ -100,6 +92,7 @@ struct sbd_duart {
#define to_sport(uport) container_of(uport, struct sbd_port, port)
static struct sbd_duart sbd_duarts[DUART_MAX_CHIP];
+static struct uart_driver sbd_reg;
/*
@@ -514,8 +507,6 @@ static void sbd_init_port(struct sbd_por
{
struct uart_port *uport = &sport->port;
- if (sport->initialised)
- return;
/*
* Contrary to documentation, which says that the transmitter
* empty bit is set when "there are no characters to send and
@@ -537,7 +528,7 @@ static void sbd_init_port(struct sbd_por
* a standard CFE firmware compilation.
*/
sbd_line_drain(sport);
- udelay(100);
+ fsleep(100);
/* There is no DUART reset feature, so just set some sane defaults. */
write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_TX);
@@ -554,8 +545,6 @@ static void sbd_init_port(struct sbd_por
/* Re-enable transmission for the initial PROM-based console. */
write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_EN);
-
- sport->initialised = 1;
}
static void sbd_set_termios(struct uart_port *uport, struct ktermios *termios,
@@ -794,50 +783,54 @@ static const struct uart_ops sbd_ops = {
};
/* Initialize SB1250 DUART port structures. */
-static void __init sbd_probe_duarts(void)
+static int __init sbd_probe(struct platform_device *pdev)
{
- static int probed;
+ struct resource *mem_resource, *irq_resource;
int chip, side;
- int max_lines, line;
- if (probed)
- return;
+ mem_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ irq_resource = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+ if (!mem_resource || !irq_resource)
+ return -ENODEV;
- /* Set the number of available units based on the SOC type. */
- switch (soc_type) {
- case K_SYS_SOC_TYPE_BCM1x55:
- case K_SYS_SOC_TYPE_BCM1x80:
- max_lines = 4;
- break;
- default:
- /* Assume at least two serial ports at the normal address. */
- max_lines = 2;
- break;
- }
+ chip = pdev->id;
+ sbd_duarts[chip].mapctrl = mem_resource->start +
+ DUART_CHANREG_SPACING * 3;
+ for (side = 0; side < DUART_MAX_SIDE; side++) {
+ struct sbd_port *sport = &sbd_duarts[chip].sport[side];
+ struct uart_port *uport = &sport->port;
- probed = 1;
+ sport->duart = &sbd_duarts[chip];
- for (chip = 0, line = 0; chip < DUART_MAX_CHIP && line < max_lines;
- chip++) {
- sbd_duarts[chip].mapctrl = SBD_CTRLREGS(line);
+ uport->dev = &pdev->dev;
+ uport->irq = irq_resource->start + side;
+ uport->uartclk = 100000000 / 20 * 16;
+ uport->fifosize = 16;
+ uport->iotype = UPIO_MEM;
+ uport->flags = UPF_BOOT_AUTOCONF;
+ uport->ops = &sbd_ops;
+ uport->line = chip * DUART_MAX_SIDE + side;
+ uport->mapbase = mem_resource->start +
+ DUART_CHANREG_SPACING * (side + 1);
+ uport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_SB1250_DUART_CONSOLE);
+ if (uart_add_one_port(&sbd_reg, uport))
+ uport->dev = NULL;
+ }
- for (side = 0; side < DUART_MAX_SIDE && line < max_lines;
- side++, line++) {
- struct sbd_port *sport = &sbd_duarts[chip].sport[side];
- struct uart_port *uport = &sport->port;
+ return 0;
+}
- sport->duart = &sbd_duarts[chip];
+static void __exit sbd_remove(struct platform_device *pdev)
+{
+ int chip, side;
- uport->irq = SBD_INT(line);
- uport->uartclk = 100000000 / 20 * 16;
- uport->fifosize = 16;
- uport->iotype = UPIO_MEM;
- uport->flags = UPF_BOOT_AUTOCONF;
- uport->ops = &sbd_ops;
- uport->line = line;
- uport->mapbase = SBD_CHANREGS(line);
- uport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_SB1250_DUART_CONSOLE);
- }
+ chip = pdev->id;
+ for (side = DUART_MAX_SIDE - 1; side >= 0; side--) {
+ struct sbd_port *sport = &sbd_duarts[chip].sport[side];
+ struct uart_port *uport = &sport->port;
+
+ if (uport->dev)
+ uart_remove_one_port(&sbd_reg, uport);
}
}
@@ -895,23 +888,14 @@ static int __init sbd_console_setup(stru
int bits = 8;
int parity = 'n';
int flow = 'n';
- int ret;
if (!sport->duart)
return -ENXIO;
-
- ret = sbd_map_port(uport);
- if (ret)
- return ret;
-
- sbd_init_port(sport);
-
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(uport, co, baud, parity, bits, flow);
}
-static struct uart_driver sbd_reg;
static struct console sbd_console = {
.name = "duart",
.write = sbd_console_write,
@@ -922,16 +906,6 @@ static struct console sbd_console = {
.data = &sbd_reg
};
-static int __init sbd_serial_console_init(void)
-{
- sbd_probe_duarts();
- register_console(&sbd_console);
-
- return 0;
-}
-
-console_initcall(sbd_serial_console_init);
-
#define SERIAL_SB1250_DUART_CONSOLE &sbd_console
#else
#define SERIAL_SB1250_DUART_CONSOLE NULL
@@ -948,43 +922,30 @@ static struct uart_driver sbd_reg = {
.cons = SERIAL_SB1250_DUART_CONSOLE,
};
+static struct platform_driver sbd_driver = {
+ .remove = __exit_p(sbd_remove),
+ .driver = { .name = "sb1250-duart" },
+};
+
/* Set up the driver and register it. */
static int __init sbd_init(void)
{
- int i, ret;
-
- sbd_probe_duarts();
+ int ret;
ret = uart_register_driver(&sbd_reg);
if (ret)
return ret;
+ ret = platform_driver_probe(&sbd_driver, sbd_probe);
+ if (ret)
+ uart_unregister_driver(&sbd_reg);
- for (i = 0; i < DUART_MAX_CHIP * DUART_MAX_SIDE; i++) {
- struct sbd_duart *duart = &sbd_duarts[i / DUART_MAX_SIDE];
- struct sbd_port *sport = &duart->sport[i % DUART_MAX_SIDE];
- struct uart_port *uport = &sport->port;
-
- if (sport->duart)
- uart_add_one_port(&sbd_reg, uport);
- }
-
- return 0;
+ return ret;
}
/* Unload the driver. Unregister stuff, get ready to go away. */
static void __exit sbd_exit(void)
{
- int i;
-
- for (i = DUART_MAX_CHIP * DUART_MAX_SIDE - 1; i >= 0; i--) {
- struct sbd_duart *duart = &sbd_duarts[i / DUART_MAX_SIDE];
- struct sbd_port *sport = &duart->sport[i % DUART_MAX_SIDE];
- struct uart_port *uport = &sport->port;
-
- if (sport->duart)
- uart_remove_one_port(&sbd_reg, uport);
- }
-
+ platform_driver_unregister(&sbd_driver);
uart_unregister_driver(&sbd_reg);
}
^ permalink raw reply
* [PATCH v2 2/4] MIPS: SiByte: Fix bootconsole handover lockup
From: Maciej W. Rozycki @ 2026-04-13 4:03 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: Elena Reshetova, David Windsor, Kees Cook, Hans Liljestrand,
linux-mips, linux-serial, linux-kernel
In-Reply-To: <alpine.DEB.2.21.2604130453400.29980@angie.orcam.me.uk>
Calling sbd_init_port() in the course of setting up the serial device
causes line parameters to be messed up and the transmitter disabled.
We've been lucky in that no message is usually produced to the kernel
log between this call and the later call to uart_set_options() in the
course of console setup done by sbd_serial_console_init(), or the system
would hang as the console output handler in CFE tried to access a port
whose transmitter has been disabled and line parameters messed up.
It'll change with the next change to the driver, so fix sbd_init_port()
such that line parameters are set for 115200n8 console operation as with
the CFE firmware and the transmitter re-enabled after reset.
Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # v6.5+
---
No change from v1.
---
drivers/tty/serial/sb1250-duart.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
linux-serial-sb1250-duart-prom-console.diff
Index: linux-macro/drivers/tty/serial/sb1250-duart.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/sb1250-duart.c
+++ linux-macro/drivers/tty/serial/sb1250-duart.c
@@ -542,14 +542,19 @@ static void sbd_init_port(struct sbd_por
/* There is no DUART reset feature, so just set some sane defaults. */
write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_TX);
write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_RX);
- write_sbdchn(sport, R_DUART_MODE_REG_1, V_DUART_BITS_PER_CHAR_8);
+ write_sbdchn(sport, R_DUART_MODE_REG_1,
+ V_DUART_PARITY_MODE_NONE | V_DUART_BITS_PER_CHAR_8);
write_sbdchn(sport, R_DUART_MODE_REG_2, 0);
+ write_sbdchn(sport, R_DUART_CLK_SEL, V_DUART_BAUD_RATE(115200));
write_sbdchn(sport, R_DUART_FULL_CTL,
V_DUART_INT_TIME(0) | V_DUART_SIG_FULL(15));
write_sbdchn(sport, R_DUART_OPCR_X, 0);
write_sbdchn(sport, R_DUART_AUXCTL_X, 0);
write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), 0);
+ /* Re-enable transmission for the initial PROM-based console. */
+ write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_EN);
+
sport->initialised = 1;
}
^ permalink raw reply
* [PATCH v2 1/4] MIPS: SiByte: Fix console message clobbering at channel resets
From: Maciej W. Rozycki @ 2026-04-13 4:03 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: Elena Reshetova, David Windsor, Kees Cook, Hans Liljestrand,
linux-mips, linux-serial, linux-kernel
In-Reply-To: <alpine.DEB.2.21.2604130453400.29980@angie.orcam.me.uk>
Ensure any characters outstanding have been sent before issuing channel
resets so as to prevent messages issued to the bootconsole from getting
clobbered.
Contrary to device documentation at the time the transmitter empty bit
is set only the transmit FIFO has been drained and there is still data
outstanding in the transmitter shift register, so wait an extra amount
of time for that register to drain too. This also prevents subsequent
messages produced to the console from getting clobbered, owing to what
seems a transmitter synchronisation issue.
When called from sbd_serial_console_init() it is too early for fsleep()
to work and even before lpj has been calculated and therefore the delay
is actually not sufficient for the transmitter to drain and is merely a
placeholder now. This will be addressed in a follow-up change.
Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # v6.5+
---
No change from v1.
---
drivers/tty/serial/sb1250-duart.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
linux-serial-sb1250-duart-reset-drain.diff
Index: linux-macro/drivers/tty/serial/sb1250-duart.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/sb1250-duart.c
+++ linux-macro/drivers/tty/serial/sb1250-duart.c
@@ -516,6 +516,28 @@ static void sbd_init_port(struct sbd_por
if (sport->initialised)
return;
+ /*
+ * Contrary to documentation, which says that the transmitter
+ * empty bit is set when "there are no characters to send and
+ * the transmitter is idle," the bit is already set by hardware
+ * once the transmit FIFO has been drained only and while the
+ * transmitter shift register still holds data being supplied
+ * to the line. Consequently issuing a transmitter reset at
+ * this point causes the final character outstanding to be lost.
+ *
+ * Moreover, resetting the transmitter while transmission is
+ * in progress appears to make the transmitter go out of sync
+ * and subsequent characters issued after the transmitter has
+ * been reprogrammed and re-enabled are sent corrupted or with
+ * their bit patterns shifted.
+ *
+ * So once the transmitter empty bit has been set wait an extra
+ * amount of time, sufficient for the transmitter shift register
+ * to drain at 115200bps, which is the baud rate setting used by
+ * a standard CFE firmware compilation.
+ */
+ sbd_line_drain(sport);
+ udelay(100);
/* There is no DUART reset feature, so just set some sane defaults. */
write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_TX);
^ permalink raw reply
* [PATCH v2 0/4] MIPS: SiByte: Fix serial device regressions
From: Maciej W. Rozycki @ 2026-04-13 4:03 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: Elena Reshetova, David Windsor, Kees Cook, Hans Liljestrand,
linux-mips, linux-serial, linux-kernel
Hi,
This v2 of the series discards a stray `i' local variable from 3/4 that
causes a compiler warning missed in verification. No functional change.
Starting from commit 84a9582fd203 ("serial: core: Start managing serial
controllers to enable runtime PM") the driver for the SiByte onchip DUART
has stopped working due to a null pointer dereference in the serial core,
which means a kernel crash at bootstrap if the driver has been enabled, as
is usually the case for the system console.
This patch series addresses the issue by switching the driver away from
legacy probing to using platform devices. A notable consequence of this
is the serial console is only switched from the bootconsole handler that
uses firmware calls over to our serial driver at the time the driver is
being properly brought up. This causes messages to be produced to the
console between the device reset and console setup, which in turn causes
the firmware still being called via the bootconsole handler to loop
forever owing to the transmitter having been disabled.
Therefore introductory change 2/4 is included to fix the issue by doing a
rudimentary device setup right after reset, using parameters compatible
with those used by the firmware (115200n8). There is auxiliary change 1/4
included as well that prevents message corruption from happening at reset,
which becomes more prominent due to the change in timing, with the driver
switch to the platform device, of messages produced to the console.
Additionally there is a revert included as change 4/4 for a regression
introduced by an earlier change that caused previously good code to fail
requesting the control register resource shared between DUART channels,
and issue a warning to the kernel log. Not to be backported as strictly
speaking the driver works just fine despite the missing reservation.
See individual change descriptions for details. Verified with a SWARM
(BCM91250A) system.
Please apply.
Maciej
^ permalink raw reply
* Re: [PATCH v4 1/4] rust: devres: return reference in `devres::register`
From: Viresh Kumar @ 2026-04-13 3:58 UTC (permalink / raw)
To: markus.probst
Cc: Rob Herring, Greg Kroah-Hartman, Jiri Slaby, Miguel Ojeda,
Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg,
Alice Ryhl, Trevor Gross, Danilo Krummrich, Kari Argillander,
Rafael J. Wysocki, Boqun Feng, David Airlie, Simona Vetter,
linux-serial, linux-kernel, rust-for-linux, linux-pm, driver-core,
dri-devel
In-Reply-To: <20260411-rust_serdev-v4-1-845e960c6627@posteo.de>
On 11-04-26, 17:10, Markus Probst via B4 Relay wrote:
> From: Markus Probst <markus.probst@posteo.de>
>
> Return the reference to the initialized data in the `devres::register`
> function.
>
> This is needed in a following commit (rust: add basic serial device bus
> abstractions).
>
> Signed-off-by: Markus Probst <markus.probst@posteo.de>
> ---
> rust/kernel/cpufreq.rs | 3 ++-
> rust/kernel/devres.rs | 15 +++++++++++++--
> rust/kernel/drm/driver.rs | 3 ++-
> 3 files changed, 17 insertions(+), 4 deletions(-)
>
> diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs
> index f5adee48d40c..31bf7e685097 100644
> --- a/rust/kernel/cpufreq.rs
> +++ b/rust/kernel/cpufreq.rs
> @@ -1052,7 +1052,8 @@ pub fn new_foreign_owned(dev: &Device<Bound>) -> Result
> where
> T: 'static,
> {
> - devres::register(dev, Self::new()?, GFP_KERNEL)
> + devres::register(dev, Self::new()?, GFP_KERNEL)?;
> + Ok(())
> }
> }
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
--
viresh
^ permalink raw reply
* [PATCH 4/4] Revert "drivers: convert sbd_duart.map_guard from atomic_t to refcount_t"
From: Maciej W. Rozycki @ 2026-04-13 3:28 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: Elena Reshetova, David Windsor, Kees Cook, Hans Liljestrand,
linux-mips, linux-serial, linux-kernel
In-Reply-To: <alpine.DEB.2.21.2604130239560.29980@angie.orcam.me.uk>
Revert commit 22a33651a56f ("drivers: convert sbd_duart.map_guard from
atomic_t to refcount_t"), which broke perfectly valid code:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 1 at lib/refcount.c:114 sbd_request_port+0x54/0x140
refcount_t: increment on 0; use-after-free.
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc2+ #34
Stack : 0000000014001fe0 0000000000000000 ffffffff80830000 0000000000000000
ffffffff8127bc7a ffffffff8016fe08 ffffffff808d0000 ffffffff808d0000
ffffffff807aa828 ffffffff80822337 ffffffff808ce188 a8000001860b0000
0000000000000001 0000000000000001 00000000000001c8 ffffffff808a3090
00000000000000bb ffffffff801b09d4 a80000018609bb68 ffffffff801231cc
ffffffff812a0000 ffffffff80171388 0000000000001000 ffffffff807aa828
0000000000000001 0000000000000001 0000000000000000 0000000000000000
0000000000000000 a80000018609bab0 0000000000000000 ffffffff803c47cc
0000000000000000 0000000000000000 0000000000000000 0000000000000000
ffffffff807cb648 ffffffff8010bff8 0000000014001fe1 ffffffff803c47cc
...
Call Trace:
[<ffffffff8010bff8>] show_stack+0x28/0x88
[<ffffffff803c47cc>] dump_stack+0x8c/0xc0
[<ffffffff801aff5c>] __warn+0xe0/0x114
[<ffffffff801233f0>] warn_slowpath_fmt+0x40/0x50
[<ffffffff80455bcc>] sbd_request_port+0x54/0x140
[<ffffffff804563a4>] sbd_config_port+0x2c/0x68
---[ end trace f666d696412caa3e ]---
(report at the offending commit) -- sbd_request_port() is called twice
per DUART instance, to reserve a resource holding the control register
block shared between the two channels, so there's no slightest chance
for an overflow. Also this doesn't stop the driver from working and
it's just the reservation that is missing as a result, i.e.:
10060100-100601ff : sb1250-duart
10060200-100602ff : sb1250-duart
as from the offending change, vs:
10060100-100601ff : sb1250-duart
10060200-100602ff : sb1250-duart
10060300-100603ff : sb1250-duart
beforehand, which is surely why the breakage has gone so long unnoticed.
"If it ain't broke, don't fix it," so just revert the broken commit.
Fixes: 22a33651a56f ("drivers: convert sbd_duart.map_guard from atomic_t to refcount_t")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
---
drivers/tty/serial/sb1250-duart.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
linux-serial-sb1250-duart-map-guard-atomic.diff
Index: linux-macro/drivers/tty/serial/sb1250-duart.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/sb1250-duart.c
+++ linux-macro/drivers/tty/serial/sb1250-duart.c
@@ -34,8 +34,8 @@
#include <linux/tty_flip.h>
#include <linux/types.h>
-#include <linux/refcount.h>
-#include <linux/io.h>
+#include <linux/atomic.h>
+#include <asm/io.h>
#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_uart.h>
@@ -86,7 +86,7 @@ struct sbd_port {
struct sbd_duart {
struct sbd_port sport[2];
unsigned long mapctrl;
- refcount_t map_guard;
+ atomic_t map_guard;
};
#define to_sport(uport) container_of(uport, struct sbd_port, port)
@@ -662,13 +662,15 @@ static void sbd_release_port(struct uart
{
struct sbd_port *sport = to_sport(uport);
struct sbd_duart *duart = sport->duart;
+ int map_guard;
iounmap(sport->memctrl);
sport->memctrl = NULL;
iounmap(uport->membase);
uport->membase = NULL;
- if(refcount_dec_and_test(&duart->map_guard))
+ map_guard = atomic_add_return(-1, &duart->map_guard);
+ if (!map_guard)
release_mem_region(duart->mapctrl, DUART_CHANREG_SPACING);
release_mem_region(uport->mapbase, DUART_CHANREG_SPACING);
}
@@ -704,6 +706,7 @@ static int sbd_request_port(struct uart_
{
const char *err = KERN_ERR "sbd: Unable to reserve MMIO resource\n";
struct sbd_duart *duart = to_sport(uport)->duart;
+ int map_guard;
int ret = 0;
if (!request_mem_region(uport->mapbase, DUART_CHANREG_SPACING,
@@ -711,11 +714,11 @@ static int sbd_request_port(struct uart_
printk(err);
return -EBUSY;
}
- refcount_inc(&duart->map_guard);
- if (refcount_read(&duart->map_guard) == 1) {
+ map_guard = atomic_add_return(1, &duart->map_guard);
+ if (map_guard == 1) {
if (!request_mem_region(duart->mapctrl, DUART_CHANREG_SPACING,
"sb1250-duart")) {
- refcount_dec(&duart->map_guard);
+ atomic_add(-1, &duart->map_guard);
printk(err);
ret = -EBUSY;
}
@@ -723,7 +726,8 @@ static int sbd_request_port(struct uart_
if (!ret) {
ret = sbd_map_port(uport);
if (ret) {
- if (refcount_dec_and_test(&duart->map_guard))
+ map_guard = atomic_add_return(-1, &duart->map_guard);
+ if (!map_guard)
release_mem_region(duart->mapctrl,
DUART_CHANREG_SPACING);
}
^ permalink raw reply
* [PATCH 3/4] MIPS: SiByte: Convert to use a platform device
From: Maciej W. Rozycki @ 2026-04-13 3:28 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: Elena Reshetova, David Windsor, Kees Cook, Hans Liljestrand,
linux-mips, linux-serial, linux-kernel
In-Reply-To: <alpine.DEB.2.21.2604130239560.29980@angie.orcam.me.uk>
Prevent a crash from happening as the first serial port is initialised:
pata-swarm: PATA interface at GenBus slot 4
workingset: timestamp_bits=62 max_order=18 bucket_order=0
Block layer SCSI generic (bsg) driver version 0.4 loaded (major 253)
CPU 1 Unable to handle kernel paging request at virtual address 0000000000000208, epc == ffffffff8067f8f8, ra == ffffffff80666330
Oops[#1]:
CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.19.0-dirty #27 NONE
$ 0 : 0000000000000000 0000000014001fe0 0000000000000020 ffffffff80666130
$ 4 : 0000000000000000 a800000100e6f118 ffffffff8112cbc0 0000000000000000
$ 8 : 0000000000000002 0000000000000000 0000000000000000 0000000001a80000
$12 : 0000000000000000 ffffffff809fd488 000000004ddf14dd ffffffff00000000
$16 : a800000100e6f000 0000000000000000 ffffffff8112c1d0 a800000100e6f000
$20 : 0000000000000000 00000000000004d0 0000000000000004 ffffffff8112c1d0
$24 : 0000000000000001 0000000000000003
$28 : a80000010007c000 a80000010007fcb0 00000000000000ef ffffffff80666330
Hi : fffffffffffffdb9
Lo : 0000000000000035
epc : ffffffff8067f8f8 __dev_fwnode+0x0/0x8
ra : ffffffff80666330 serial_base_ctrl_add+0xb8/0x180
Status: 14001fe3 KX SX UX KERNEL EXL IE
Cause : 80800008 (ExcCode 02)
BadVA : 0000000000000208
PrId : 03040102 (SiByte SB1)
Process swapper/0 (pid: 1, threadinfo=(____ptrval____), task=(____ptrval____), tls=0000000000000000)
Stack : 0000000000000000 ffffffff80cd5178 ffffffff80cd0000 ffffffff8112c1c8
0000000000000260 ffffffff806655c4 a800000100275bc0 ffffffff8064ac88
004000408112c000 0000000000000002 0000000000000000 ffffffff801965d0
a800000100786ba0 ffffffff80cd5178 a800000100786ba0 0000000000000004
a800000100275bc0 0000000000000000 0000000000000000 ffffffff80cd5178
0000000000000000 ffffffff8112c1c8 0000000000000260 00000000000004d0
0000000000000004 ffffffff80bf0000 00000000000000ef ffffffff80d171dc
ffffffff80d17120 ffffffff80d25658 0000000000000000 ffffffff80d50000
ffffffff80d2f928 ffffffff80d50000 ffffffff80d25698 ffffffff80cfcecc
00ffffff80b84428 0000000000000000 0000000000000006 0000000000000006
...
Call Trace:
[<ffffffff8067f8f8>] __dev_fwnode+0x0/0x8
[<ffffffff80666330>] serial_base_ctrl_add+0xb8/0x180
[<ffffffff806655c4>] serial_core_register_port+0x174/0x8e0
[<ffffffff80d171dc>] sbd_init+0xbc/0xf4
[<ffffffff80cfcecc>] do_one_initcall+0x64/0x150
[<ffffffff80cfd284>] kernel_init_freeable+0x25c/0x30c
[<ffffffff809ff6e4>] kernel_init+0x24/0x118
[<ffffffff80112d20>] ret_from_kernel_thread+0x14/0x1c
Code: 67bd0010 03e00008 2402ffea <03e00008> dc820208 67bdffa0 ffbe0050 ffb70048 ffb60040
---[ end trace 0000000000000000 ]---
-- where a pointer is dereferenced that has been derived from a null
pointer to the port's parent device.
Since no device is available with legacy probing and it's not anymore a
preferable way to discover devices anyway, switch the driver to using a
platform device and use it as the port's parent device.
Use platform_driver_probe() because SB1250 DUART devices are embedded
onchip the SoC and therefore not that straightforward to remove.
An unfortunate consequence of the switch to a platform device is we now
hand the console over from the bootconsole much later in the bootstrap.
The CFE console handler appears good enough though to work so late and
in particular with interrupts enabled.
Conversely only starting the console port so late lets the reset code
fully utilise our delay handlers, so switch from udelay() to fsleep()
for transmitter draining so as to avoid busy-waiting for an excessive
amount of time.
Since there is one way only remaining to reach sbd_init_port() now, drop
the port initialisation marker as no longer needed and go through the
channel resets unconditionally.
Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # needs to use .remove_new for <= 6.10
---
arch/mips/sibyte/swarm/platform.c | 97 +++++++++++++++++++++++-
drivers/tty/serial/sb1250-duart.c | 148 ++++++++++++++------------------------
2 files changed, 146 insertions(+), 99 deletions(-)
linux-serial-sb1250-duart-platform.diff
Index: linux-macro/arch/mips/sibyte/swarm/platform.c
===================================================================
--- linux-macro.orig/arch/mips/sibyte/swarm/platform.c
+++ linux-macro/arch/mips/sibyte/swarm/platform.c
@@ -8,7 +8,13 @@
#include <asm/sibyte/board.h>
#include <asm/sibyte/sb1250_genbus.h>
+#if defined(CONFIG_SIBYTE_BCM1x80)
+#include <asm/sibyte/bcm1480_regs.h>
+#include <asm/sibyte/bcm1480_int.h>
+#else
#include <asm/sibyte/sb1250_regs.h>
+#include <asm/sibyte/sb1250_int.h>
+#endif
#if defined(CONFIG_SIBYTE_SWARM) || defined(CONFIG_SIBYTE_LITTLESUR)
@@ -85,6 +91,82 @@ device_initcall(swarm_pata_init);
#endif /* defined(CONFIG_SIBYTE_SWARM) || defined(CONFIG_SIBYTE_LITTLESUR) */
+#if defined(CONFIG_SIBYTE_BCM1x80)
+static struct resource sb1250_duart_resources[][2] = {
+ {
+ {
+ .name = "sb1250-duart0",
+ .flags = IORESOURCE_MEM,
+ .start = A_BCM1480_DUART0,
+ .end = (A_BCM1480_DUART0 +
+ 4 * BCM1480_DUART_CHANREG_SPACING - 1),
+ },
+ {
+ .name = "sb1250-duart0",
+ .flags = IORESOURCE_IRQ,
+ .start = K_BCM1480_INT_UART_0,
+ .end = K_BCM1480_INT_UART_1,
+ },
+ },
+ {
+ {
+ .name = "sb1250-duart1",
+ .flags = IORESOURCE_MEM,
+ .start = A_BCM1480_DUART1,
+ .end = (A_BCM1480_DUART1 +
+ 4 * BCM1480_DUART_CHANREG_SPACING - 1),
+ },
+ {
+ .name = "sb1250-duart1",
+ .flags = IORESOURCE_IRQ,
+ .start = K_BCM1480_INT_UART_2,
+ .end = K_BCM1480_INT_UART_3,
+ },
+ },
+};
+#else /* !defined(CONFIG_SIBYTE_BCM1x80) */
+static struct resource sb1250_duart_resources[][2] = {
+ {
+ {
+ .name = "sb1250-duart0",
+ .flags = IORESOURCE_MEM,
+ .start = A_DUART,
+ .end = A_DUART + 4 * DUART_CHANREG_SPACING - 1,
+ },
+ {
+ .name = "sb1250-duart0",
+ .flags = IORESOURCE_IRQ,
+ .start = K_INT_UART_0,
+ .end = K_INT_UART_1,
+ },
+ },
+};
+#endif /* !defined(CONFIG_SIBYTE_BCM1x80) */
+
+static struct platform_device sb1250_duart_device[] = {
+ {
+ .name = "sb1250-duart",
+ .id = 0,
+ .resource = sb1250_duart_resources[0],
+ .num_resources = ARRAY_SIZE(sb1250_duart_resources[0]),
+ },
+#if defined(CONFIG_SIBYTE_BCM1x80)
+ {
+ .name = "sb1250-duart",
+ .id = 1,
+ .resource = sb1250_duart_resources[1],
+ .num_resources = ARRAY_SIZE(sb1250_duart_resources[1]),
+ },
+#endif
+};
+
+static struct platform_device *sb1250_duart_devices[] __initdata = {
+ &sb1250_duart_device[0],
+#if defined(CONFIG_SIBYTE_BCM1x80)
+ &sb1250_duart_device[1],
+#endif
+};
+
#define sb1250_dev_struct(num) \
static struct resource sb1250_res##num = { \
.name = "SB1250 MAC " __stringify(num), \
@@ -113,28 +195,31 @@ static struct platform_device *sb1250_de
static int __init sb1250_device_init(void)
{
- int ret;
+ int ret1, ret2;
+
+ ret1 = platform_add_devices(sb1250_duart_devices,
+ ARRAY_SIZE(sb1250_duart_devices));
/* Set the number of available units based on the SOC type. */
switch (soc_type) {
case K_SYS_SOC_TYPE_BCM1250:
case K_SYS_SOC_TYPE_BCM1250_ALT:
- ret = platform_add_devices(sb1250_devs, 3);
+ ret2 = platform_add_devices(sb1250_devs, 3);
break;
case K_SYS_SOC_TYPE_BCM1120:
case K_SYS_SOC_TYPE_BCM1125:
case K_SYS_SOC_TYPE_BCM1125H:
case K_SYS_SOC_TYPE_BCM1250_ALT2: /* Hybrid */
- ret = platform_add_devices(sb1250_devs, 2);
+ ret2 = platform_add_devices(sb1250_devs, 2);
break;
case K_SYS_SOC_TYPE_BCM1x55:
case K_SYS_SOC_TYPE_BCM1x80:
- ret = platform_add_devices(sb1250_devs, 4);
+ ret2 = platform_add_devices(sb1250_devs, 4);
break;
default:
- ret = -ENODEV;
+ ret2 = 0;
break;
}
- return ret;
+ return ret1 ? ret1 : ret2;
}
device_initcall(sb1250_device_init);
Index: linux-macro/drivers/tty/serial/sb1250-duart.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/sb1250-duart.c
+++ linux-macro/drivers/tty/serial/sb1250-duart.c
@@ -3,7 +3,7 @@
* Support for the asynchronous serial interface (DUART) included
* in the BCM1250 and derived System-On-a-Chip (SOC) devices.
*
- * Copyright (c) 2007 Maciej W. Rozycki
+ * Copyright (c) 2007, 2026 Maciej W. Rozycki
*
* Derived from drivers/char/sb1250_duart.c for which the following
* copyright applies:
@@ -25,6 +25,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/major.h>
+#include <linux/platform_device.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/spinlock.h>
@@ -45,10 +46,6 @@
#include <asm/sibyte/bcm1480_regs.h>
#include <asm/sibyte/bcm1480_int.h>
-#define SBD_CHANREGS(line) A_BCM1480_DUART_CHANREG((line), 0)
-#define SBD_CTRLREGS(line) A_BCM1480_DUART_CTRLREG((line), 0)
-#define SBD_INT(line) (K_BCM1480_INT_UART_0 + (line))
-
#define DUART_CHANREG_SPACING BCM1480_DUART_CHANREG_SPACING
#define R_DUART_IMRREG(line) R_BCM1480_DUART_IMRREG(line)
@@ -59,10 +56,6 @@
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_int.h>
-#define SBD_CHANREGS(line) A_DUART_CHANREG((line), 0)
-#define SBD_CTRLREGS(line) A_DUART_CTRLREG(0)
-#define SBD_INT(line) (K_INT_UART_0 + (line))
-
#else
#error invalid SB1250 UART configuration
@@ -85,7 +78,6 @@ struct sbd_port {
struct uart_port port;
unsigned char __iomem *memctrl;
int tx_stopped;
- int initialised;
};
/*
@@ -100,6 +92,7 @@ struct sbd_duart {
#define to_sport(uport) container_of(uport, struct sbd_port, port)
static struct sbd_duart sbd_duarts[DUART_MAX_CHIP];
+static struct uart_driver sbd_reg;
/*
@@ -514,8 +507,6 @@ static void sbd_init_port(struct sbd_por
{
struct uart_port *uport = &sport->port;
- if (sport->initialised)
- return;
/*
* Contrary to documentation, which says that the transmitter
* empty bit is set when "there are no characters to send and
@@ -537,7 +528,7 @@ static void sbd_init_port(struct sbd_por
* a standard CFE firmware compilation.
*/
sbd_line_drain(sport);
- udelay(100);
+ fsleep(100);
/* There is no DUART reset feature, so just set some sane defaults. */
write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_TX);
@@ -554,8 +545,6 @@ static void sbd_init_port(struct sbd_por
/* Re-enable transmission for the initial PROM-based console. */
write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_EN);
-
- sport->initialised = 1;
}
static void sbd_set_termios(struct uart_port *uport, struct ktermios *termios,
@@ -794,50 +783,55 @@ static const struct uart_ops sbd_ops = {
};
/* Initialize SB1250 DUART port structures. */
-static void __init sbd_probe_duarts(void)
+static int __init sbd_probe(struct platform_device *pdev)
{
- static int probed;
+ struct resource *mem_resource, *irq_resource;
int chip, side;
- int max_lines, line;
+ int i;
- if (probed)
- return;
+ mem_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ irq_resource = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+ if (!mem_resource || !irq_resource)
+ return -ENODEV;
- /* Set the number of available units based on the SOC type. */
- switch (soc_type) {
- case K_SYS_SOC_TYPE_BCM1x55:
- case K_SYS_SOC_TYPE_BCM1x80:
- max_lines = 4;
- break;
- default:
- /* Assume at least two serial ports at the normal address. */
- max_lines = 2;
- break;
- }
+ chip = pdev->id;
+ sbd_duarts[chip].mapctrl = mem_resource->start +
+ DUART_CHANREG_SPACING * 3;
+ for (side = 0; side < DUART_MAX_SIDE; side++) {
+ struct sbd_port *sport = &sbd_duarts[chip].sport[side];
+ struct uart_port *uport = &sport->port;
- probed = 1;
+ sport->duart = &sbd_duarts[chip];
- for (chip = 0, line = 0; chip < DUART_MAX_CHIP && line < max_lines;
- chip++) {
- sbd_duarts[chip].mapctrl = SBD_CTRLREGS(line);
+ uport->dev = &pdev->dev;
+ uport->irq = irq_resource->start + side;
+ uport->uartclk = 100000000 / 20 * 16;
+ uport->fifosize = 16;
+ uport->iotype = UPIO_MEM;
+ uport->flags = UPF_BOOT_AUTOCONF;
+ uport->ops = &sbd_ops;
+ uport->line = chip * DUART_MAX_SIDE + side;
+ uport->mapbase = mem_resource->start +
+ DUART_CHANREG_SPACING * (side + 1);
+ uport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_SB1250_DUART_CONSOLE);
+ if (uart_add_one_port(&sbd_reg, uport))
+ uport->dev = NULL;
+ }
- for (side = 0; side < DUART_MAX_SIDE && line < max_lines;
- side++, line++) {
- struct sbd_port *sport = &sbd_duarts[chip].sport[side];
- struct uart_port *uport = &sport->port;
+ return 0;
+}
- sport->duart = &sbd_duarts[chip];
+static void __exit sbd_remove(struct platform_device *pdev)
+{
+ int chip, side;
- uport->irq = SBD_INT(line);
- uport->uartclk = 100000000 / 20 * 16;
- uport->fifosize = 16;
- uport->iotype = UPIO_MEM;
- uport->flags = UPF_BOOT_AUTOCONF;
- uport->ops = &sbd_ops;
- uport->line = line;
- uport->mapbase = SBD_CHANREGS(line);
- uport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_SB1250_DUART_CONSOLE);
- }
+ chip = pdev->id;
+ for (side = DUART_MAX_SIDE - 1; side >= 0; side--) {
+ struct sbd_port *sport = &sbd_duarts[chip].sport[side];
+ struct uart_port *uport = &sport->port;
+
+ if (uport->dev)
+ uart_remove_one_port(&sbd_reg, uport);
}
}
@@ -895,23 +889,14 @@ static int __init sbd_console_setup(stru
int bits = 8;
int parity = 'n';
int flow = 'n';
- int ret;
if (!sport->duart)
return -ENXIO;
-
- ret = sbd_map_port(uport);
- if (ret)
- return ret;
-
- sbd_init_port(sport);
-
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(uport, co, baud, parity, bits, flow);
}
-static struct uart_driver sbd_reg;
static struct console sbd_console = {
.name = "duart",
.write = sbd_console_write,
@@ -922,16 +907,6 @@ static struct console sbd_console = {
.data = &sbd_reg
};
-static int __init sbd_serial_console_init(void)
-{
- sbd_probe_duarts();
- register_console(&sbd_console);
-
- return 0;
-}
-
-console_initcall(sbd_serial_console_init);
-
#define SERIAL_SB1250_DUART_CONSOLE &sbd_console
#else
#define SERIAL_SB1250_DUART_CONSOLE NULL
@@ -948,43 +923,30 @@ static struct uart_driver sbd_reg = {
.cons = SERIAL_SB1250_DUART_CONSOLE,
};
+static struct platform_driver sbd_driver = {
+ .remove = __exit_p(sbd_remove),
+ .driver = { .name = "sb1250-duart" },
+};
+
/* Set up the driver and register it. */
static int __init sbd_init(void)
{
- int i, ret;
-
- sbd_probe_duarts();
+ int ret;
ret = uart_register_driver(&sbd_reg);
if (ret)
return ret;
+ ret = platform_driver_probe(&sbd_driver, sbd_probe);
+ if (ret)
+ uart_unregister_driver(&sbd_reg);
- for (i = 0; i < DUART_MAX_CHIP * DUART_MAX_SIDE; i++) {
- struct sbd_duart *duart = &sbd_duarts[i / DUART_MAX_SIDE];
- struct sbd_port *sport = &duart->sport[i % DUART_MAX_SIDE];
- struct uart_port *uport = &sport->port;
-
- if (sport->duart)
- uart_add_one_port(&sbd_reg, uport);
- }
-
- return 0;
+ return ret;
}
/* Unload the driver. Unregister stuff, get ready to go away. */
static void __exit sbd_exit(void)
{
- int i;
-
- for (i = DUART_MAX_CHIP * DUART_MAX_SIDE - 1; i >= 0; i--) {
- struct sbd_duart *duart = &sbd_duarts[i / DUART_MAX_SIDE];
- struct sbd_port *sport = &duart->sport[i % DUART_MAX_SIDE];
- struct uart_port *uport = &sport->port;
-
- if (sport->duart)
- uart_remove_one_port(&sbd_reg, uport);
- }
-
+ platform_driver_unregister(&sbd_driver);
uart_unregister_driver(&sbd_reg);
}
^ permalink raw reply
* [PATCH 2/4] MIPS: SiByte: Fix bootconsole handover lockup
From: Maciej W. Rozycki @ 2026-04-13 3:28 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: Elena Reshetova, David Windsor, Kees Cook, Hans Liljestrand,
linux-mips, linux-serial, linux-kernel
In-Reply-To: <alpine.DEB.2.21.2604130239560.29980@angie.orcam.me.uk>
Calling sbd_init_port() in the course of setting up the serial device
causes line parameters to be messed up and the transmitter disabled.
We've been lucky in that no message is usually produced to the kernel
log between this call and the later call to uart_set_options() in the
course of console setup done by sbd_serial_console_init(), or the system
would hang as the console output handler in CFE tried to access a port
whose transmitter has been disabled and line parameters messed up.
It'll change with the next change to the driver, so fix sbd_init_port()
such that line parameters are set for 115200n8 console operation as with
the CFE firmware and the transmitter re-enabled after reset.
Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # v6.5+
---
drivers/tty/serial/sb1250-duart.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
linux-serial-sb1250-duart-prom-console.diff
Index: linux-macro/drivers/tty/serial/sb1250-duart.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/sb1250-duart.c
+++ linux-macro/drivers/tty/serial/sb1250-duart.c
@@ -542,14 +542,19 @@ static void sbd_init_port(struct sbd_por
/* There is no DUART reset feature, so just set some sane defaults. */
write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_TX);
write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_RX);
- write_sbdchn(sport, R_DUART_MODE_REG_1, V_DUART_BITS_PER_CHAR_8);
+ write_sbdchn(sport, R_DUART_MODE_REG_1,
+ V_DUART_PARITY_MODE_NONE | V_DUART_BITS_PER_CHAR_8);
write_sbdchn(sport, R_DUART_MODE_REG_2, 0);
+ write_sbdchn(sport, R_DUART_CLK_SEL, V_DUART_BAUD_RATE(115200));
write_sbdchn(sport, R_DUART_FULL_CTL,
V_DUART_INT_TIME(0) | V_DUART_SIG_FULL(15));
write_sbdchn(sport, R_DUART_OPCR_X, 0);
write_sbdchn(sport, R_DUART_AUXCTL_X, 0);
write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), 0);
+ /* Re-enable transmission for the initial PROM-based console. */
+ write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_EN);
+
sport->initialised = 1;
}
^ permalink raw reply
* [PATCH 1/4] MIPS: SiByte: Fix console message clobbering at channel resets
From: Maciej W. Rozycki @ 2026-04-13 3:28 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: Elena Reshetova, David Windsor, Kees Cook, Hans Liljestrand,
linux-mips, linux-serial, linux-kernel
In-Reply-To: <alpine.DEB.2.21.2604130239560.29980@angie.orcam.me.uk>
Ensure any characters outstanding have been sent before issuing channel
resets so as to prevent messages issued to the bootconsole from getting
clobbered.
Contrary to device documentation at the time the transmitter empty bit
is set only the transmit FIFO has been drained and there is still data
outstanding in the transmitter shift register, so wait an extra amount
of time for that register to drain too. This also prevents subsequent
messages produced to the console from getting clobbered, owing to what
seems a transmitter synchronisation issue.
When called from sbd_serial_console_init() it is too early for fsleep()
to work and even before lpj has been calculated and therefore the delay
is actually not sufficient for the transmitter to drain and is merely a
placeholder now. This will be addressed in a follow-up change.
Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # v6.5+
---
drivers/tty/serial/sb1250-duart.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
linux-serial-sb1250-duart-reset-drain.diff
Index: linux-macro/drivers/tty/serial/sb1250-duart.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/sb1250-duart.c
+++ linux-macro/drivers/tty/serial/sb1250-duart.c
@@ -516,6 +516,28 @@ static void sbd_init_port(struct sbd_por
if (sport->initialised)
return;
+ /*
+ * Contrary to documentation, which says that the transmitter
+ * empty bit is set when "there are no characters to send and
+ * the transmitter is idle," the bit is already set by hardware
+ * once the transmit FIFO has been drained only and while the
+ * transmitter shift register still holds data being supplied
+ * to the line. Consequently issuing a transmitter reset at
+ * this point causes the final character outstanding to be lost.
+ *
+ * Moreover, resetting the transmitter while transmission is
+ * in progress appears to make the transmitter go out of sync
+ * and subsequent characters issued after the transmitter has
+ * been reprogrammed and re-enabled are sent corrupted or with
+ * their bit patterns shifted.
+ *
+ * So once the transmitter empty bit has been set wait an extra
+ * amount of time, sufficient for the transmitter shift register
+ * to drain at 115200bps, which is the baud rate setting used by
+ * a standard CFE firmware compilation.
+ */
+ sbd_line_drain(sport);
+ udelay(100);
/* There is no DUART reset feature, so just set some sane defaults. */
write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_TX);
^ permalink raw reply
* [PATCH 0/4] MIPS: SiByte: Fix serial device regressions
From: Maciej W. Rozycki @ 2026-04-13 3:28 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: Elena Reshetova, David Windsor, Kees Cook, Hans Liljestrand,
linux-mips, linux-serial, linux-kernel
Hi,
Starting from commit 84a9582fd203 ("serial: core: Start managing serial
controllers to enable runtime PM") the driver for the SiByte onchip DUART
has stopped working due to a null pointer dereference in the serial core,
which means a kernel crash at bootstrap if the driver has been enabled, as
is usually the case for the system console.
This patch series addresses the issue by switching the driver away from
legacy probing to using platform devices. A notable consequence of this
is the serial console is only switched from the bootconsole handler that
uses firmware calls over to our serial driver at the time the driver is
being properly brought up. This causes messages to be produced to the
console between the device reset and console setup, which in turn causes
the firmware still being called via the bootconsole handler to loop
forever owing to the transmitter having been disabled.
Therefore introductory change 2/4 is included to fix the issue by doing a
rudimentary device setup right after reset, using parameters compatible
with those used by the firmware (115200n8). There is auxiliary change 1/4
included as well that prevents message corruption from happening at reset,
which becomes more prominent due to the change in timing, with the driver
switch to the platform device, of messages produced to the console.
Additionally there is a revert included as change 4/4 for a regression
introduced by an earlier change that caused previously good code to fail
requesting the control register resource shared between DUART channels,
and issue a warning to the kernel log. Not to be backported as strictly
speaking the driver works just fine despite the missing reservation.
See individual change descriptions for details. Verified with a SWARM
(BCM91250A) system.
Please apply.
Maciej
^ permalink raw reply
* [PATCH 8/8] MIPS: DEC: Ensure RTC platform device deregistration upon failure
From: Maciej W. Rozycki @ 2026-04-13 3:28 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: linux-mips, linux-serial, linux-serial
In-Reply-To: <alpine.DEB.2.21.2604102250060.29980@angie.orcam.me.uk>
Switch RTC platform device registration from platform_device_register()
to platform_add_devices() so as to make sure any failure will result in
automatic device deregistration.
Fixes: fae67ad43114 ("arch/mips/dec: switch DECstation systems to rtc-cmos")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
---
arch/mips/dec/platform.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
linux-mips-dec-platform-rtc-unregister.diff
Index: linux-macro/arch/mips/dec/platform.c
===================================================================
--- linux-macro.orig/arch/mips/dec/platform.c
+++ linux-macro/arch/mips/dec/platform.c
@@ -38,6 +38,10 @@ static struct platform_device dec_rtc_de
.num_resources = ARRAY_SIZE(dec_rtc_resources),
};
+static struct platform_device *dec_rtc_devices[] __initdata = {
+ &dec_rtc_device,
+};
+
static struct resource dec_dz_resources[] = {
{ .name = "dz", .flags = IORESOURCE_MEM, },
{ .name = "dz", .flags = IORESOURCE_IRQ, },
@@ -137,7 +141,7 @@ static int __init dec_add_devices(void)
}
num_zs = i;
- ret1 = platform_device_register(&dec_rtc_device);
+ ret1 = platform_add_devices(dec_rtc_devices, 1);
ret2 = IS_ENABLED(CONFIG_32BIT) ?
platform_add_devices(dec_dz_devices, num_dz) : 0;
ret3 = platform_add_devices(dec_zs_devices, num_zs);
^ permalink raw reply
* [PATCH 7/8] serial: dz: Enable modular build
From: Maciej W. Rozycki @ 2026-04-13 3:28 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: linux-mips, linux-serial, linux-serial
In-Reply-To: <alpine.DEB.2.21.2604102250060.29980@angie.orcam.me.uk>
Enable modular build since the driver now has a proper module_exit()
handler. There's nothing specific to DZ hardware to prevent driver
unloading and reloading from working.
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
---
drivers/tty/serial/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
linux-serial-dz-module.diff
Index: linux-macro/drivers/tty/serial/Kconfig
===================================================================
--- linux-macro.orig/drivers/tty/serial/Kconfig
+++ linux-macro/drivers/tty/serial/Kconfig
@@ -335,7 +335,7 @@ config SERIAL_MAX310X
Say Y here if you want to support this ICs.
config SERIAL_DZ
- bool "DECstation DZ serial driver"
+ tristate "DECstation DZ serial driver"
depends on MACH_DECSTATION && 32BIT
select SERIAL_CORE
default y
^ permalink raw reply
* [PATCH 6/8] serial: zs: Convert to use a platform device
From: Maciej W. Rozycki @ 2026-04-13 3:28 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: linux-mips, linux-serial, linux-serial
In-Reply-To: <alpine.DEB.2.21.2604102250060.29980@angie.orcam.me.uk>
Prevent a crash from happening as the first serial port is initialised:
Console: switching to mono frame buffer device 160x64
fb0: PMAG-AA frame buffer device at tc0
DECstation Z85C30 serial driver version 0.10
CPU 0 Unable to handle kernel paging request at virtual address 0000002c, epc == 803ab00c, ra == 803aafe0
Oops[#1]:
CPU: 0 PID: 1 Comm: swapper Not tainted 6.4.0-rc3-00031-g84a9582fd203-dirty #57
$ 0 : 00000000 10012c00 803aaeb0 00000000
$ 4 : 80e12f60 80e12f50 80e12f58 81000030
$ 8 : 00000000 805ff37c 00000000 33433538
$12 : 65732030 00000006 80c2915d 6c616972
$16 : 80e12f00 807b7630 00000000 00000000
$20 : 00000004 00000348 000001a0 807623b8
$24 : 00000018 00000000
$28 : 80c24000 80c25d60 8078b148 803aafe0
Hi : 00000000
Lo : 00000000
epc : 803ab00c serial_base_ctrl_add+0x78/0xf4
ra : 803aafe0 serial_base_ctrl_add+0x4c/0xf4
Status: 10012c03 KERNEL EXL IE
Cause : 00000008 (ExcCode 02)
BadVA : 0000002c
PrId : 00000440 (R4400SC)
Modules linked in:
Process swapper (pid: 1, threadinfo=(ptrval), task=(ptrval), tls=00000000)
Stack : 80760000 00000cc0 00400044 00400040 803aa02c 80d61ab8 00000000 807b7630
80760000 807623b8 807b7628 803aa644 80386998 00000000 80e17780 80220f68
80e17780 80d61ab8 80c17d80 80e17780 80e17780 8063c798 80e17780 80383fa0
00000010 80e17780 00000000 80386998 807a0000 00000000 00400040 8038f848
807623b8 80d61ab8 00000004 80e17780 00000000 803a68e4 80c25e2c 803bb884
...
Call Trace:
[<803ab00c>] serial_base_ctrl_add+0x78/0xf4
[<803aa644>] serial_core_register_port+0x174/0x69c
[<8077e9ac>] zs_init+0xc8/0xfc
[<800404d4>] do_one_initcall+0x40/0x2ac
[<8076cecc>] kernel_init_freeable+0x1e4/0x270
[<80605bec>] kernel_init+0x20/0x108
[<800431e8>] ret_from_kernel_thread+0x14/0x1c
Code: 2442aeb0 ae120024 ae0200d0 <8c67002c> 50e00001 8c670000 3c06806e 3c05806e afb30010
---[ end trace 0000000000000000 ]---
(report at the offending commit) -- where a pointer is dereferenced that
has been derived from a null pointer to the port's parent device.
Since no device is available with legacy probing and it's not anymore a
preferable way to discover devices anyway, switch the driver to using a
platform device and use it as the port's parent device. Update resource
handling accordingly and only request the actual span of addresses used
within the slot, which will have had its resource already requested by
generic platform device code.
Use platform_driver_probe() not just because SCC devices are fixed with
solder on board and not straightforward to remove, but foremost because
the associated TTY's major device number is the same as used by the dz
driver and the first driver to claim it will prevent the other one from
using it. Either one DZ device or some SCC devices will be present in a
given system but never both at a time, and therefore we want the major
device number to be claimed by the first driver to actually successfully
bind to its device and platform_driver_probe() is a way to fulfil that.
An unfortunate consequence of the switch to a platform device is we now
hand the console over from the bootconsole much later in the bootstrap.
The firmware console handler appears good enough though to work so late
and in particular with interrupts enabled.
Since there is one way only remaining to reach zs_reset() now, remove
the port initialisation marker as no longer needed and go through the
channel reset unconditionally.
Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # needs to use .remove_new for <= 6.10
---
arch/mips/dec/platform.c | 60 ++++++++++++++-
drivers/tty/serial/zs.c | 184 +++++++++++++++++------------------------------
drivers/tty/serial/zs.h | 1
3 files changed, 125 insertions(+), 120 deletions(-)
linux-serial-zs-platform.diff
Index: linux-macro/arch/mips/dec/platform.c
===================================================================
--- linux-macro.orig/arch/mips/dec/platform.c
+++ linux-macro/arch/mips/dec/platform.c
@@ -13,6 +13,7 @@
#include <asm/bootinfo.h>
#include <asm/dec/interrupts.h>
+#include <asm/dec/ioasic_addrs.h>
#include <asm/dec/kn01.h>
#include <asm/dec/kn02.h>
#include <asm/dec/system.h>
@@ -53,10 +54,37 @@ static struct platform_device *dec_dz_de
&dec_dz_device,
};
+static struct resource dec_zs_resources[][2] = {
+ {
+ { .name = "scc0", .flags = IORESOURCE_MEM, },
+ { .name = "scc0", .flags = IORESOURCE_IRQ, },
+ },
+ {
+ { .name = "scc1", .flags = IORESOURCE_MEM, },
+ { .name = "scc1", .flags = IORESOURCE_IRQ, },
+ },
+};
+
+static struct platform_device dec_zs_device[] = {
+ {
+ .name = "zs",
+ .id = 0,
+ .resource = dec_zs_resources[0],
+ .num_resources = ARRAY_SIZE(dec_zs_resources[0]),
+ },
+ {
+ .name = "zs",
+ .id = 1,
+ .resource = dec_zs_resources[1],
+ .num_resources = ARRAY_SIZE(dec_zs_resources[1]),
+ },
+};
+
static int __init dec_add_devices(void)
{
- int ret1, ret2;
- int num_dz;
+ struct platform_device *dec_zs_devices[ARRAY_SIZE(dec_zs_device)];
+ int ret1, ret2, ret3;
+ int num_dz, num_zs;
int irq, i;
dec_rtc_resources[0].start = RTC_PORT(0);
@@ -84,10 +112,36 @@ static int __init dec_add_devices(void)
}
num_dz = i;
+ i = 0;
+ irq = dec_interrupt[DEC_IRQ_SCC0];
+ if (irq >= 0) {
+ resource_size_t base = dec_kn_slot_base + IOASIC_SCC0;
+
+ dec_zs_device[i].resource[0].start = base;
+ dec_zs_device[i].resource[0].end = base + dec_kn_slot_size - 1;
+ dec_zs_device[i].resource[1].start = irq;
+ dec_zs_device[i].resource[1].end = irq;
+ dec_zs_devices[i] = &dec_zs_device[i];
+ i++;
+ }
+ irq = dec_interrupt[DEC_IRQ_SCC1];
+ if (irq >= 0) {
+ resource_size_t base = dec_kn_slot_base + IOASIC_SCC1;
+
+ dec_zs_device[i].resource[0].start = base;
+ dec_zs_device[i].resource[0].end = base + dec_kn_slot_size - 1;
+ dec_zs_device[i].resource[1].start = irq;
+ dec_zs_device[i].resource[1].end = irq;
+ dec_zs_devices[i] = &dec_zs_device[i];
+ i++;
+ }
+ num_zs = i;
+
ret1 = platform_device_register(&dec_rtc_device);
ret2 = IS_ENABLED(CONFIG_32BIT) ?
platform_add_devices(dec_dz_devices, num_dz) : 0;
- return ret1 ? ret1 : ret2;
+ ret3 = platform_add_devices(dec_zs_devices, num_zs);
+ return ret1 ? ret1 : ret2 ? ret2 : ret3;
}
device_initcall(dec_add_devices);
Index: linux-macro/drivers/tty/serial/zs.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/zs.c
+++ linux-macro/drivers/tty/serial/zs.c
@@ -56,6 +56,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/major.h>
+#include <linux/platform_device.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/spinlock.h>
@@ -66,10 +67,6 @@
#include <linux/atomic.h>
-#include <asm/dec/interrupts.h>
-#include <asm/dec/ioasic_addrs.h>
-#include <asm/dec/system.h>
-
#include "zs.h"
@@ -79,7 +76,7 @@ MODULE_LICENSE("GPL");
static char zs_name[] __initdata = "DECstation Z85C30 serial driver version ";
-static char zs_version[] __initdata = "0.10";
+static char zs_version[] __initdata = "0.11";
/*
* It would be nice to dynamically allocate everything that
@@ -98,12 +95,8 @@ static char zs_version[] __initdata = "0
#define to_zport(uport) container_of(uport, struct zs_port, port)
-struct zs_parms {
- resource_size_t scc[ZS_NUM_SCCS];
- int irq[ZS_NUM_SCCS];
-};
-
static struct zs_scc zs_sccs[ZS_NUM_SCCS];
+static struct uart_driver zs_reg;
/*
* Set parameters in WR5, WR12, WR13 such as not to interfere
@@ -839,16 +832,15 @@ static void zs_reset(struct zs_port *zpo
spin_lock_irqsave(&scc->zlock, flags);
irq = !irqs_disabled_flags(flags);
- if (!zport->initialised) {
- /* Reset the pointer first, just in case... */
- read_zsreg(zport, R0);
- /* And let the current transmission finish. */
- zs_line_drain(zport, irq);
- write_zsreg(zport, R9, zport == zport_a ? CHRA : CHRB);
- udelay(10);
- write_zsreg(zport, R9, 0);
- zport->initialised = 1;
- }
+
+ /* Reset the pointer first, just in case... */
+ read_zsreg(zport, R0);
+ /* And let the current transmission finish. */
+ zs_line_drain(zport, irq);
+ write_zsreg(zport, R9, zport == zport_a ? CHRA : CHRB);
+ udelay(10);
+ write_zsreg(zport, R9, 0);
+
load_zsregs(zport, zport->regs, irq);
spin_unlock_irqrestore(&scc->zlock, flags);
}
@@ -1055,63 +1047,62 @@ static const struct uart_ops zs_ops = {
/*
* Initialize Z85C30 port structures.
*/
-static int __init zs_probe_sccs(void)
+static int __init zs_probe(struct platform_device *pdev)
{
- static int probed;
- struct zs_parms zs_parms;
- int chip, side, irq;
- int n_chips = 0;
+ struct resource *mem_resource, *irq_resource;
+ int chip, side;
int i;
- if (probed)
- return 0;
-
- irq = dec_interrupt[DEC_IRQ_SCC0];
- if (irq >= 0) {
- zs_parms.scc[n_chips] = IOASIC_SCC0;
- zs_parms.irq[n_chips] = dec_interrupt[DEC_IRQ_SCC0];
- n_chips++;
- }
- irq = dec_interrupt[DEC_IRQ_SCC1];
- if (irq >= 0) {
- zs_parms.scc[n_chips] = IOASIC_SCC1;
- zs_parms.irq[n_chips] = dec_interrupt[DEC_IRQ_SCC1];
- n_chips++;
- }
- if (!n_chips)
- return -ENXIO;
+ mem_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ irq_resource = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+ if (!mem_resource || !irq_resource)
+ return -ENODEV;
- probed = 1;
+ chip = pdev->id;
+ spin_lock_init(&zs_sccs[chip].zlock);
+ for (side = 0; side < ZS_NUM_CHAN; side++) {
+ struct zs_port *zport = &zs_sccs[chip].zport[side];
+ struct uart_port *uport = &zport->port;
- for (chip = 0; chip < n_chips; chip++) {
- spin_lock_init(&zs_sccs[chip].zlock);
- for (side = 0; side < ZS_NUM_CHAN; side++) {
- struct zs_port *zport = &zs_sccs[chip].zport[side];
- struct uart_port *uport = &zport->port;
+ zport->scc = &zs_sccs[chip];
+ zport->clk_mode = 16;
- zport->scc = &zs_sccs[chip];
- zport->clk_mode = 16;
+ uport->dev = &pdev->dev;
+ uport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_ZS_CONSOLE);
+ uport->irq = irq_resource->start;
+ uport->uartclk = ZS_CLOCK;
+ uport->fifosize = 1;
+ uport->iotype = UPIO_MEM;
+ uport->flags = UPF_BOOT_AUTOCONF;
+ uport->ops = &zs_ops;
+ uport->line = chip * ZS_NUM_CHAN + side;
+ uport->mapbase = mem_resource->start +
+ (side ^ ZS_CHAN_B) * ZS_CHAN_IO_SIZE;
- uport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_ZS_CONSOLE);
- uport->irq = zs_parms.irq[chip];
- uport->uartclk = ZS_CLOCK;
- uport->fifosize = 1;
- uport->iotype = UPIO_MEM;
- uport->flags = UPF_BOOT_AUTOCONF;
- uport->ops = &zs_ops;
- uport->line = chip * ZS_NUM_CHAN + side;
- uport->mapbase = dec_kn_slot_base +
- zs_parms.scc[chip] +
- (side ^ ZS_CHAN_B) * ZS_CHAN_IO_SIZE;
+ for (i = 0; i < ZS_NUM_REGS; i++)
+ zport->regs[i] = zs_init_regs[i];
- for (i = 0; i < ZS_NUM_REGS; i++)
- zport->regs[i] = zs_init_regs[i];
- }
+ if (uart_add_one_port(&zs_reg, uport))
+ uport->dev = NULL;
}
return 0;
}
+static void __exit zs_remove(struct platform_device *pdev)
+{
+ int chip, side;
+
+ chip = pdev->id;
+ for (side = ZS_NUM_CHAN - 1; side >= 0; side--) {
+ struct zs_port *zport = &zs_sccs[chip].zport[side];
+ struct uart_port *uport = &zport->port;
+
+ if (uport->dev)
+ uart_remove_one_port(&zs_reg, uport);
+ }
+}
+
#ifdef CONFIG_SERIAL_ZS_CONSOLE
static void zs_console_putchar(struct uart_port *uport, unsigned char ch)
@@ -1192,20 +1183,14 @@ static int __init zs_console_setup(struc
int bits = 8;
int parity = 'n';
int flow = 'n';
- int ret;
-
- ret = zs_map_port(uport);
- if (ret)
- return ret;
-
- zs_reset(zport);
+ if (!zport->scc)
+ return -ENODEV;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(uport, co, baud, parity, bits, flow);
}
-static struct uart_driver zs_reg;
static struct console zs_console = {
.name = "ttyS",
.write = zs_console_write,
@@ -1216,23 +1201,6 @@ static struct console zs_console = {
.data = &zs_reg,
};
-/*
- * Register console.
- */
-static int __init zs_serial_console_init(void)
-{
- int ret;
-
- ret = zs_probe_sccs();
- if (ret)
- return ret;
- register_console(&zs_console);
-
- return 0;
-}
-
-console_initcall(zs_serial_console_init);
-
#define SERIAL_ZS_CONSOLE &zs_console
#else
#define SERIAL_ZS_CONSOLE NULL
@@ -1248,47 +1216,31 @@ static struct uart_driver zs_reg = {
.cons = SERIAL_ZS_CONSOLE,
};
+static struct platform_driver zs_driver = {
+ .remove = __exit_p(zs_remove),
+ .driver = { .name = "zs" },
+};
+
/* zs_init inits the driver. */
static int __init zs_init(void)
{
- int i, ret;
+ int ret;
pr_info("%s%s\n", zs_name, zs_version);
- /* Find out how many Z85C30 SCCs we have. */
- ret = zs_probe_sccs();
- if (ret)
- return ret;
-
ret = uart_register_driver(&zs_reg);
if (ret)
return ret;
+ ret = platform_driver_probe(&zs_driver, zs_probe);
+ if (ret)
+ uart_unregister_driver(&zs_reg);
- for (i = 0; i < ZS_NUM_SCCS * ZS_NUM_CHAN; i++) {
- struct zs_scc *scc = &zs_sccs[i / ZS_NUM_CHAN];
- struct zs_port *zport = &scc->zport[i % ZS_NUM_CHAN];
- struct uart_port *uport = &zport->port;
-
- if (zport->scc)
- uart_add_one_port(&zs_reg, uport);
- }
-
- return 0;
+ return ret;
}
static void __exit zs_exit(void)
{
- int i;
-
- for (i = ZS_NUM_SCCS * ZS_NUM_CHAN - 1; i >= 0; i--) {
- struct zs_scc *scc = &zs_sccs[i / ZS_NUM_CHAN];
- struct zs_port *zport = &scc->zport[i % ZS_NUM_CHAN];
- struct uart_port *uport = &zport->port;
-
- if (zport->scc)
- uart_remove_one_port(&zs_reg, uport);
- }
-
+ platform_driver_unregister(&zs_driver);
uart_unregister_driver(&zs_reg);
}
Index: linux-macro/drivers/tty/serial/zs.h
===================================================================
--- linux-macro.orig/drivers/tty/serial/zs.h
+++ linux-macro/drivers/tty/serial/zs.h
@@ -22,7 +22,6 @@
struct zs_port {
struct zs_scc *scc; /* Containing SCC. */
struct uart_port port; /* Underlying UART. */
- int initialised; /* For the console port. */
int clk_mode; /* May be 1, 16, 32, or 64. */
^ permalink raw reply
* [PATCH 5/8] serial: dz: Convert to use a platform device
From: Maciej W. Rozycki @ 2026-04-13 3:28 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: linux-mips, linux-serial, linux-serial
In-Reply-To: <alpine.DEB.2.21.2604102250060.29980@angie.orcam.me.uk>
Prevent a crash from happening as the first serial port is initialised:
Console: switching to colour frame buffer device 160x64
tgafb: SFB+ detected, rev=0x02
fb0: Digital ZLX-E1 frame buffer device at 0x1e000000
DECstation DZ serial driver version 1.04
CPU 0 Unable to handle kernel paging request at virtual address 000000bc, epc == 8048b3a4, ra == 80470a78
Oops[#1]:
CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.19.0-dirty #35 NONE
$ 0 : 00000000 1000ac00 00000004 804707ac
$ 4 : 00000000 80e20850 80e20858 81000030
$ 8 : 00000000 8072c81c 00000008 fefefeff
$12 : 6c616972 00000006 80c5917f 69726420
$16 : 80e20800 00000000 808f8968 80e20800
$20 : 00000000 807f5a90 808b0094 808d3bc8
$24 : 00000018 80479030
$28 : 80c2e000 80c2fd70 00000069 80470a78
Hi : 00000004
Lo : 00000000
epc : 8048b3a4 __dev_fwnode+0x0/0xc
ra : 80470a78 serial_base_ctrl_add+0xa0/0x168
Status: 1000ac04 IEp
Cause : 30000008 (ExcCode 02)
BadVA : 000000bc
PrId : 00000220 (R3000)
Modules linked in:
Process swapper/0 (pid: 1, threadinfo=(ptrval), task=(ptrval), tls=00000000)
Stack : 00400044 00400040 8046f4cc 00000000 808a6148 808a0000 808f8968 8086983c
808e0000 8046fc84 1000ac01 00000028 80e20700 802ba3f8 80e20700 80d34a94
80c1b900 80e20700 80e20700 80e20700 80e20700 80444650 00000000 00000000
00000000 807f5a90 808b0094 80447080 00400040 808e0000 80d34a94 808a6148
80d34a94 00000004 80e20700 00000000 8076974c 80469810 80c2fe3c 1000ac01
...
Call Trace:
[<8048b3a4>] __dev_fwnode+0x0/0xc
[<80470a78>] serial_base_ctrl_add+0xa0/0x168
[<8046fc84>] serial_core_register_port+0x1c8/0x974
[<808c6af0>] dz_init+0x74/0xc8
[<800470e0>] do_one_initcall+0x44/0x2d4
[<808b111c>] kernel_init_freeable+0x258/0x308
[<8072e434>] kernel_init+0x20/0x114
[<80049cd0>] ret_from_kernel_thread+0x14/0x1c
Code: 27bd0018 03e00008 2402ffea <8c8200bc> 03e00008 00000000 27bdffc0 afbe0038 afb30024
---[ end trace 0000000000000000 ]---
-- where a pointer is dereferenced that has been derived from a null
pointer to the port's parent device.
Since no device is available with legacy probing and it's not anymore a
preferable way to discover devices anyway, switch the driver to using a
platform device and use it as the port's parent device. Update resource
handling accordingly and only request the actual span of addresses used
within the slot, which will have had its resource already requested by
generic platform device code.
Use platform_driver_probe() not just because the DZ device is fixed with
solder on board and not straightforward to remove, but foremost because
the associated TTY's major device number is the same as used by the zs
driver and the first driver to claim it will prevent the other one from
using it. Either one DZ device or some SCC devices will be present in a
given system but never both at a time, and therefore we want the major
device number to be claimed by the first driver to actually successfully
bind to its device and platform_driver_probe() is a way to fulfil that.
An unfortunate consequence of the switch to a platform device is we now
hand the console over from the bootconsole much later in the bootstrap.
The firmware console handler appears good enough though to work so late
and in particular with interrupts enabled.
Conversely only starting the console port so late lets the reset code
fully utilise our delay handlers, so switch from udelay() to fsleep()
for transmitter draining so as to avoid busy-waiting for an excessive
amount of time.
Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # needs to use .remove_new for <= 6.10
---
arch/mips/dec/platform.c | 55 +++++++++++++++++++++-
drivers/tty/serial/dz.c | 116 ++++++++++++++++++++++-------------------------
2 files changed, 110 insertions(+), 61 deletions(-)
linux-serial-dz-platform.diff
Index: linux-macro/arch/mips/dec/platform.c
===================================================================
--- linux-macro.orig/arch/mips/dec/platform.c
+++ linux-macro/arch/mips/dec/platform.c
@@ -10,6 +10,13 @@
#include <linux/mc146818rtc.h>
#include <linux/platform_device.h>
+#include <asm/bootinfo.h>
+
+#include <asm/dec/interrupts.h>
+#include <asm/dec/kn01.h>
+#include <asm/dec/kn02.h>
+#include <asm/dec/system.h>
+
static struct resource dec_rtc_resources[] = {
{
.name = "rtc",
@@ -30,11 +37,57 @@ static struct platform_device dec_rtc_de
.num_resources = ARRAY_SIZE(dec_rtc_resources),
};
+static struct resource dec_dz_resources[] = {
+ { .name = "dz", .flags = IORESOURCE_MEM, },
+ { .name = "dz", .flags = IORESOURCE_IRQ, },
+};
+
+static struct platform_device dec_dz_device = {
+ .name = "dz",
+ .id = PLATFORM_DEVID_NONE,
+ .resource = dec_dz_resources,
+ .num_resources = ARRAY_SIZE(dec_dz_resources),
+};
+
+static struct platform_device *dec_dz_devices[] __initdata = {
+ &dec_dz_device,
+};
+
static int __init dec_add_devices(void)
{
+ int ret1, ret2;
+ int num_dz;
+ int irq, i;
+
dec_rtc_resources[0].start = RTC_PORT(0);
dec_rtc_resources[0].end = RTC_PORT(0) + dec_kn_slot_size - 1;
- return platform_device_register(&dec_rtc_device);
+
+ i = 0;
+ irq = dec_interrupt[DEC_IRQ_DZ11];
+ if (IS_ENABLED(CONFIG_32BIT) && irq >= 0) {
+ resource_size_t base;
+
+ switch (mips_machtype) {
+ case MACH_DS23100:
+ case MACH_DS5100:
+ base = dec_kn_slot_base + KN01_DZ11;
+ break;
+ default:
+ base = dec_kn_slot_base + KN02_DZ11;
+ break;
+ }
+ dec_dz_device.resource[0].start = base;
+ dec_dz_device.resource[0].end = base + dec_kn_slot_size - 1;
+ dec_dz_device.resource[1].start = irq;
+ dec_dz_device.resource[1].end = irq;
+ i++;
+ }
+ num_dz = i;
+
+ ret1 = platform_device_register(&dec_rtc_device);
+ ret2 = IS_ENABLED(CONFIG_32BIT) ?
+ platform_add_devices(dec_dz_devices, num_dz) : 0;
+ return ret1 ? ret1 : ret2;
}
device_initcall(dec_add_devices);
Index: linux-macro/drivers/tty/serial/dz.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/dz.c
+++ linux-macro/drivers/tty/serial/dz.c
@@ -40,6 +40,7 @@
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/module.h>
+#include <linux/platform_device.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/sysrq.h>
@@ -48,14 +49,6 @@
#include <linux/atomic.h>
#include <linux/io.h>
-#include <asm/bootinfo.h>
-
-#include <asm/dec/interrupts.h>
-#include <asm/dec/kn01.h>
-#include <asm/dec/kn02.h>
-#include <asm/dec/machtype.h>
-#include <asm/dec/prom.h>
-#include <asm/dec/system.h>
#include "dz.h"
@@ -65,7 +58,9 @@ MODULE_LICENSE("GPL");
static char dz_name[] __initdata = "DECstation DZ serial driver version ";
-static char dz_version[] __initdata = "1.04";
+static char dz_version[] __initdata = "1.05";
+
+#define DZ_IO_SIZE 0x20 /* IOMEM space size. */
struct dz_port {
struct dz_mux *mux;
@@ -81,6 +76,7 @@ struct dz_mux {
};
static struct dz_mux dz_mux;
+static struct uart_driver dz_reg;
static inline struct dz_port *to_dport(struct uart_port *uport)
{
@@ -564,7 +560,7 @@ static void dz_reset(struct dz_port *dpo
iob();
udelay(2); /* 1.4us TRDY recovery. */
}
- udelay(1200); /* Transmitter drain. */
+ fsleep(1200); /* Transmitter drain. */
}
dz_out(dport, DZ_CSR, DZ_CLR);
@@ -681,14 +677,13 @@ static void dz_release_port(struct uart_
map_guard = atomic_add_return(-1, &mux->map_guard);
if (!map_guard)
- release_mem_region(uport->mapbase, dec_kn_slot_size);
+ release_mem_region(uport->mapbase, DZ_IO_SIZE);
}
static int dz_map_port(struct uart_port *uport)
{
if (!uport->membase)
- uport->membase = ioremap(uport->mapbase,
- dec_kn_slot_size);
+ uport->membase = ioremap(uport->mapbase, DZ_IO_SIZE);
if (!uport->membase) {
printk(KERN_ERR "dz: Cannot map MMIO\n");
return -ENOMEM;
@@ -704,8 +699,7 @@ static int dz_request_port(struct uart_p
map_guard = atomic_add_return(1, &mux->map_guard);
if (map_guard == 1) {
- if (!request_mem_region(uport->mapbase, dec_kn_slot_size,
- "dz")) {
+ if (!request_mem_region(uport->mapbase, DZ_IO_SIZE, "dz")) {
atomic_add(-1, &mux->map_guard);
printk(KERN_ERR
"dz: Unable to reserve MMIO resource\n");
@@ -716,7 +710,7 @@ static int dz_request_port(struct uart_p
if (ret) {
map_guard = atomic_add_return(-1, &mux->map_guard);
if (!map_guard)
- release_mem_region(uport->mapbase, dec_kn_slot_size);
+ release_mem_region(uport->mapbase, DZ_IO_SIZE);
return ret;
}
return 0;
@@ -768,20 +762,15 @@ static const struct uart_ops dz_ops = {
.verify_port = dz_verify_port,
};
-static void __init dz_init_ports(void)
+static int __init dz_probe(struct platform_device *pdev)
{
- static int first = 1;
- unsigned long base;
+ struct resource *mem_resource, *irq_resource;
int line;
- if (!first)
- return;
- first = 0;
-
- if (mips_machtype == MACH_DS23100 || mips_machtype == MACH_DS5100)
- base = dec_kn_slot_base + KN01_DZ11;
- else
- base = dec_kn_slot_base + KN02_DZ11;
+ mem_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ irq_resource = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+ if (!mem_resource || !irq_resource)
+ return -ENODEV;
for (line = 0; line < DZ_NB_PORT; line++) {
struct dz_port *dport = &dz_mux.dport[line];
@@ -789,14 +778,33 @@ static void __init dz_init_ports(void)
dport->mux = &dz_mux;
- uport->irq = dec_interrupt[DEC_IRQ_DZ11];
+ uport->dev = &pdev->dev;
+ uport->irq = irq_resource->start;
uport->fifosize = 1;
uport->iotype = UPIO_MEM;
uport->flags = UPF_BOOT_AUTOCONF;
uport->ops = &dz_ops;
uport->line = line;
- uport->mapbase = base;
+ uport->mapbase = mem_resource->start;
uport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_DZ_CONSOLE);
+
+ if (uart_add_one_port(&dz_reg, uport))
+ uport->dev = NULL;
+ }
+
+ return 0;
+}
+
+static void __exit dz_remove(struct platform_device *pdev)
+{
+ int line;
+
+ for (line = DZ_NB_PORT - 1; line >= 0; line--) {
+ struct dz_port *dport = &dz_mux.dport[line];
+ struct uart_port *uport = &dport->port;
+
+ if (uport->dev)
+ uart_remove_one_port(&dz_reg, uport);
}
}
@@ -879,21 +887,14 @@ static int __init dz_console_setup(struc
int bits = 8;
int parity = 'n';
int flow = 'n';
- int ret;
-
- ret = dz_map_port(uport);
- if (ret)
- return ret;
-
- dz_reset(dport);
+ if (!dport->mux)
+ return -ENODEV;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
-
- return uart_set_options(&dport->port, co, baud, parity, bits, flow);
+ return uart_set_options(uport, co, baud, parity, bits, flow);
}
-static struct uart_driver dz_reg;
static struct console dz_console = {
.name = "ttyS",
.write = dz_console_print,
@@ -904,18 +905,6 @@ static struct console dz_console = {
.data = &dz_reg,
};
-static int __init dz_serial_console_init(void)
-{
- if (!IOASIC) {
- dz_init_ports();
- register_console(&dz_console);
- return 0;
- } else
- return -ENXIO;
-}
-
-console_initcall(dz_serial_console_init);
-
#define SERIAL_DZ_CONSOLE &dz_console
#else
#define SERIAL_DZ_CONSOLE NULL
@@ -931,25 +920,32 @@ static struct uart_driver dz_reg = {
.cons = SERIAL_DZ_CONSOLE,
};
+static struct platform_driver dz_driver = {
+ .remove = __exit_p(dz_remove),
+ .driver = { .name = "dz" },
+};
+
static int __init dz_init(void)
{
- int ret, i;
-
- if (IOASIC)
- return -ENXIO;
+ int ret;
printk("%s%s\n", dz_name, dz_version);
- dz_init_ports();
-
ret = uart_register_driver(&dz_reg);
if (ret)
return ret;
+ ret = platform_driver_probe(&dz_driver, dz_probe);
+ if (ret)
+ uart_unregister_driver(&dz_reg);
- for (i = 0; i < DZ_NB_PORT; i++)
- uart_add_one_port(&dz_reg, &dz_mux.dport[i].port);
+ return ret;
+}
- return 0;
+static void __exit dz_exit(void)
+{
+ platform_driver_unregister(&dz_driver);
+ uart_unregister_driver(&dz_reg);
}
module_init(dz_init);
+module_exit(dz_exit);
^ permalink raw reply
* [PATCH 4/8] serial: zs: Switch to using channel reset
From: Maciej W. Rozycki @ 2026-04-13 3:28 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: linux-mips, linux-serial, linux-serial
In-Reply-To: <alpine.DEB.2.21.2604102250060.29980@angie.orcam.me.uk>
Switch the driver to using the channel reset rather than hardware reset,
simplifying handling by removing an interference between channels that
causes the other channel to become uninitialised afterwards.
There is little difference between the two kinds of reset in terms of
register settings that result, and we initialise the whole register set
right away anyway. However this prevents a hang from happening should
the console output handler in the firmware try to access the other port
whose transmitter has been disabled and line parameters messed up.
For example this will happen if the keyboard port (port A) is chosen for
the system console, unusually but not insanely for a headless system, as
the port is wired to a standard DA-15 connector and an adapter can be
easily made. Or with the next change in place this would happen for the
regular console port (port B), since the keyboard port (port A) will be
initialised first.
Just remove the unnecessary complication then, a channel reset is good
enough. We still need the initialisation marker, now per channel rather
than per SCC, as for the console port zs_reset() will be called twice:
once early on via zs_serial_console_init() for the console setup only,
and then again via zs_config_port() as the port is associated with a TTY
device.
Fixes: 8b4a40809e53 ("zs: move to the serial subsystem")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # v2.6.23+
---
drivers/tty/serial/zs.c | 7 ++++---
drivers/tty/serial/zs.h | 2 +-
2 files changed, 5 insertions(+), 4 deletions(-)
linux-serial-zs-reset-channel.diff
Index: linux-macro/drivers/tty/serial/zs.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/zs.c
+++ linux-macro/drivers/tty/serial/zs.c
@@ -832,21 +832,22 @@ static void zs_shutdown(struct uart_port
static void zs_reset(struct zs_port *zport)
{
+ struct zs_port *zport_a = &zport->scc->zport[ZS_CHAN_A];
struct zs_scc *scc = zport->scc;
int irq;
unsigned long flags;
spin_lock_irqsave(&scc->zlock, flags);
irq = !irqs_disabled_flags(flags);
- if (!scc->initialised) {
+ if (!zport->initialised) {
/* Reset the pointer first, just in case... */
read_zsreg(zport, R0);
/* And let the current transmission finish. */
zs_line_drain(zport, irq);
- write_zsreg(zport, R9, FHWRES);
+ write_zsreg(zport, R9, zport == zport_a ? CHRA : CHRB);
udelay(10);
write_zsreg(zport, R9, 0);
- scc->initialised = 1;
+ zport->initialised = 1;
}
load_zsregs(zport, zport->regs, irq);
spin_unlock_irqrestore(&scc->zlock, flags);
Index: linux-macro/drivers/tty/serial/zs.h
===================================================================
--- linux-macro.orig/drivers/tty/serial/zs.h
+++ linux-macro/drivers/tty/serial/zs.h
@@ -22,6 +22,7 @@
struct zs_port {
struct zs_scc *scc; /* Containing SCC. */
struct uart_port port; /* Underlying UART. */
+ int initialised; /* For the console port. */
int clk_mode; /* May be 1, 16, 32, or 64. */
@@ -41,7 +42,6 @@ struct zs_scc {
struct zs_port zport[2];
spinlock_t zlock;
atomic_t irq_guard;
- int initialised;
};
#endif /* __KERNEL__ */
^ permalink raw reply
* [PATCH 3/8] serial: zs: Fix bootconsole handover lockup
From: Maciej W. Rozycki @ 2026-04-13 3:28 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: linux-mips, linux-serial, linux-serial
In-Reply-To: <alpine.DEB.2.21.2604102250060.29980@angie.orcam.me.uk>
Calling zs_reset() in the course of setting up the serial device causes
line parameters to be reset and the transmitter disabled. We've been
lucky in that no message is usually produced to the kernel log between
this call and the later call to uart_set_options() in the course of
console setup done by zs_serial_console_init(), or the system would hang
as the console output handler in the firmware tried to access a port
whose transmitter has been disabled and line parameters messed up.
This will change with the next change to the driver, so fix zs_reset()
such that line parameters are set for 9600n8 console operation as with
the system firmware and the transmitter re-enabled after reset. This
also means zs_pm() serves no purpose anymore, so drop it.
Switch to using the channel reset rather than the hardware reset, since
this simplifies handling by removing the interfere
Fixes: 8b4a40809e53 ("zs: move to the serial subsystem")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # v2.6.23+
---
drivers/tty/serial/zs.c | 29 ++++++++---------------------
1 file changed, 8 insertions(+), 21 deletions(-)
linux-serial-zs-prom-console.diff
Index: linux-macro/drivers/tty/serial/zs.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/zs.c
+++ linux-macro/drivers/tty/serial/zs.c
@@ -105,18 +105,24 @@ struct zs_parms {
static struct zs_scc zs_sccs[ZS_NUM_SCCS];
+/*
+ * Set parameters in WR5, WR12, WR13 such as not to interfere
+ * with the initial PROM-based console. Otherwise any output
+ * produced before the console handover would cause the system
+ * firmware to hang (TxENAB) or produce rubbish (Tx8, B9600).
+ */
static u8 zs_init_regs[ZS_NUM_REGS] __initdata = {
0, /* write 0 */
PAR_SPEC, /* write 1 */
0, /* write 2 */
0, /* write 3 */
X16CLK | SB1, /* write 4 */
- 0, /* write 5 */
+ Tx8 | TxENAB, /* write 5 */
0, 0, 0, /* write 6, 7, 8 */
MIE | DLC | NV, /* write 9 */
NRZ, /* write 10 */
TCBR | RCBR, /* write 11 */
- 0, 0, /* BRG time constant, write 12 + 13 */
+ 0x16, 0x00, /* BRG time constant, write 12 + 13 */
BRSRC | BRENABL, /* write 14 */
0, /* write 15 */
};
@@ -956,23 +962,6 @@ static void zs_set_termios(struct uart_p
spin_unlock_irqrestore(&scc->zlock, flags);
}
-/*
- * Hack alert!
- * Required solely so that the initial PROM-based console
- * works undisturbed in parallel with this one.
- */
-static void zs_pm(struct uart_port *uport, unsigned int state,
- unsigned int oldstate)
-{
- struct zs_port *zport = to_zport(uport);
-
- if (state < 3)
- zport->regs[5] |= TxENAB;
- else
- zport->regs[5] &= ~TxENAB;
- write_zsreg(zport, R5, zport->regs[5]);
-}
-
static const char *zs_type(struct uart_port *uport)
{
@@ -1055,7 +1044,6 @@ static const struct uart_ops zs_ops = {
.startup = zs_startup,
.shutdown = zs_shutdown,
.set_termios = zs_set_termios,
- .pm = zs_pm,
.type = zs_type,
.release_port = zs_release_port,
.request_port = zs_request_port,
@@ -1210,7 +1198,6 @@ static int __init zs_console_setup(struc
return ret;
zs_reset(zport);
- zs_pm(uport, 0, -1);
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
^ permalink raw reply
* [PATCH 2/8] serial: dz: Fix bootconsole handover lockup
From: Maciej W. Rozycki @ 2026-04-13 3:28 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: linux-mips, linux-serial, linux-serial
In-Reply-To: <alpine.DEB.2.21.2604102250060.29980@angie.orcam.me.uk>
Calling dz_reset() in the course of setting up the serial device causes
line parameters to be reset and the transmitter disabled. We've been
lucky in that no message is usually produced to the kernel log between
this call and the later call to uart_set_options() in the course of
console setup done by dz_serial_console_init(), or the system would hang
as the console output handler in the firmware tried to access a port
whose transmitter has been disabled and line parameters messed up.
This will change with the next change to the driver, so fix dz_reset()
such that line parameters are set for 9600n8 console operation as with
the system firmware and the transmitter re-enabled after reset. This
also means dz_pm() serves no purpose anymore, so drop it.
Fixes: e6ee512f5a77 ("dz.c: Resource management")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # v2.6.25+
---
drivers/tty/serial/dz.c | 36 ++++++++++++------------------------
1 file changed, 12 insertions(+), 24 deletions(-)
linux-serial-dz-prom-console.diff
Index: linux-macro/drivers/tty/serial/dz.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/dz.c
+++ linux-macro/drivers/tty/serial/dz.c
@@ -571,6 +571,18 @@ static void dz_reset(struct dz_port *dpo
while (dz_in(dport, DZ_CSR) & DZ_CLR);
iob();
+ /*
+ * Set parameters across all lines such as not to interfere
+ * with the initial PROM-based console. Otherwise any output
+ * produced before the console handover would cause the system
+ * firmware to produce rubbish.
+ */
+ for (int line = 0; line < DZ_NB_PORT; line++)
+ dz_out(dport, DZ_LPR, DZ_B9600 | DZ_CS8 | line);
+
+ /* Re-enable transmission for the initial PROM-based console. */
+ dz_out(dport, DZ_TCR, tcr);
+
/* Enable scanning. */
dz_out(dport, DZ_CSR, DZ_MSE);
@@ -654,26 +666,6 @@ static void dz_set_termios(struct uart_p
uart_port_unlock_irqrestore(&dport->port, flags);
}
-/*
- * Hack alert!
- * Required solely so that the initial PROM-based console
- * works undisturbed in parallel with this one.
- */
-static void dz_pm(struct uart_port *uport, unsigned int state,
- unsigned int oldstate)
-{
- struct dz_port *dport = to_dport(uport);
- unsigned long flags;
-
- uart_port_lock_irqsave(&dport->port, &flags);
- if (state < 3)
- dz_start_tx(&dport->port);
- else
- dz_stop_tx(&dport->port);
- uart_port_unlock_irqrestore(&dport->port, flags);
-}
-
-
static const char *dz_type(struct uart_port *uport)
{
return "DZ";
@@ -769,7 +761,6 @@ static const struct uart_ops dz_ops = {
.startup = dz_startup,
.shutdown = dz_shutdown,
.set_termios = dz_set_termios,
- .pm = dz_pm,
.type = dz_type,
.release_port = dz_release_port,
.request_port = dz_request_port,
@@ -894,10 +885,7 @@ static int __init dz_console_setup(struc
if (ret)
return ret;
- spin_lock_init(&dport->port.lock); /* For dz_pm(). */
-
dz_reset(dport);
- dz_pm(uport, 0, -1);
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
^ permalink raw reply
* [PATCH 1/8] serial: dz: Fix bootconsole message clobbering at chip reset
From: Maciej W. Rozycki @ 2026-04-13 3:27 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: linux-mips, linux-serial, linux-serial
In-Reply-To: <alpine.DEB.2.21.2604102250060.29980@angie.orcam.me.uk>
In the DZ interface as implemented by the DC7085 gate array the serial
transmitters are double buffered, meaning that at the time a transmitter
is ready to accept the next character there is one in the transmit shift
register still being sent to the line. Issuing a master clear at this
time causes this character to be lost, so wait an extra amount of time
sufficient for the transmit shift register to drain at 9600bps, which is
the baud rate setting used by the firmware console.
Mind the specified 1.4us TRDY recovery time in the course and continue
using iob() as the completion barrier, since the platforms involved use
a write buffer that can delay and combine writes, and reorder them with
respect to reads regardless of the MMIO locations accessed and we still
lack a platform-independent handler for that.
When called from dz_serial_console_init() this is too early for fsleep()
to work and even before lpj has been calculated and therefore the delay
is actually not sufficient for the transmitter to drain and is merely a
placeholder now. This will be addressed in a follow-up change.
Fixes: e6ee512f5a77 ("dz.c: Resource management")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # v2.6.25+
---
drivers/tty/serial/dz.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
linux-serial-dz-reset-drain.diff
Index: linux-macro/drivers/tty/serial/dz.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/dz.c
+++ linux-macro/drivers/tty/serial/dz.c
@@ -542,10 +542,31 @@ static int dz_encode_baud_rate(unsigned
static void dz_reset(struct dz_port *dport)
{
struct dz_mux *mux = dport->mux;
+ unsigned short tcr;
+ int loops = 10000;
if (mux->initialised)
return;
+ tcr = dz_in(dport, DZ_TCR);
+
+ /* Do not disturb any ongoing transmissions. */
+ if (dz_in(dport, DZ_CSR) & DZ_MSE) {
+ unsigned short csr, mask;
+
+ mask = tcr;
+ while ((mask & DZ_LNENB) && loops--) {
+ csr = dz_in(dport, DZ_CSR);
+ if (!(csr & DZ_TRDY))
+ continue;
+ mask &= ~(1 << ((csr & DZ_TLINE) >> 8));
+ dz_out(dport, DZ_TCR, mask);
+ iob();
+ udelay(2); /* 1.4us TRDY recovery. */
+ }
+ udelay(1200); /* Transmitter drain. */
+ }
+
dz_out(dport, DZ_CSR, DZ_CLR);
while (dz_in(dport, DZ_CSR) & DZ_CLR);
iob();
^ permalink raw reply
* [PATCH 0/8] MIPS: DEC: Fix serial device regressions + RTC cleanup
From: Maciej W. Rozycki @ 2026-04-13 3:27 UTC (permalink / raw)
To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby
Cc: linux-mips, linux-serial, linux-serial
Hi,
Starting from commit 84a9582fd203 ("serial: core: Start managing serial
controllers to enable runtime PM") drivers for serial devices used with
the DEC platform have stopped working due to a null pointer dereference in
the serial core, which means a kernel crash at bootstrap if the relevant
driver has been enabled, as is usually the case for the system console.
This patch series addresses the issue by switching the drivers away from
legacy probing to using platform devices. A notable consequence of this
is the serial console is only switched from the bootconsole handler that
uses firmware calls over to our serial driver at the time the driver is
being properly brought up. This causes messages to be produced to the
console between the device reset and console setup, which in turn causes
the firmware still being called via the bootconsole handler to loop
forever owing to the transmitter having been disabled.
Both drivers are affected and therefore introductory changes 2/8 and 3/8
are included to fix the issue by doing a rudimentary device setup right
after reset, using parameters compatible with those used by the firmware
(9600n8). There are auxiliary changes 1/8 and 4/8 included as well, that
respectively prevent a message corruption regression from happening at
reset due to the change in timing of messages produced to the console with
the dz driver switch to the platform device, and simplify reset handling
in the zs driver by issuing a channel rather hardware reset. Then 5/8 and
6/8 actually switch the respective drivers to use platform devices.
A tiny update follows, 7/8, that enables modular build for the dz driver,
not to be backported as not a bug fix.
Finally 8/8 is a small cleanup for the existing RTC device, included in
the series and then last only, due to a mechanical dependency and neither
for backporting, as it only addresses a code quality issue for a failure
scenario that is not expected to trigger in reality.
See individual change descriptions for details. Verified with a 5000/200
machine for the dz driver, and with 5000/150 and 5000/260 systems for the
zs driver.
Please apply.
Maciej
^ permalink raw reply
* [PATCH v4 2/4] serdev: add rust private data to serdev_device
From: Markus Probst via B4 Relay @ 2026-04-11 15:10 UTC (permalink / raw)
To: Rob Herring, Greg Kroah-Hartman, Jiri Slaby, Miguel Ojeda,
Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg,
Alice Ryhl, Trevor Gross, Danilo Krummrich, Kari Argillander,
Rafael J. Wysocki, Viresh Kumar, Boqun Feng, David Airlie,
Simona Vetter, Boqun Feng
Cc: linux-serial, linux-kernel, rust-for-linux, linux-pm, driver-core,
dri-devel, Markus Probst
In-Reply-To: <20260411-rust_serdev-v4-0-845e960c6627@posteo.de>
From: Markus Probst <markus.probst@posteo.de>
Add rust private data to `struct serdev_device`, as it is required by the
rust abstraction added in the following commit
(rust: add basic serial device bus abstractions).
Signed-off-by: Markus Probst <markus.probst@posteo.de>
---
include/linux/serdev.h | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index 5654c58eb73c..c74c345d60ae 100644
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -33,12 +33,14 @@ struct serdev_device_ops {
/**
* struct serdev_device - Basic representation of an serdev device
- * @dev: Driver model representation of the device.
- * @nr: Device number on serdev bus.
- * @ctrl: serdev controller managing this device.
- * @ops: Device operations.
- * @write_comp Completion used by serdev_device_write() internally
- * @write_lock Lock to serialize access when writing data
+ * @dev: Driver model representation of the device.
+ * @nr: Device number on serdev bus.
+ * @ctrl: serdev controller managing this device.
+ * @ops: Device operations.
+ * @write_comp: Completion used by serdev_device_write() internally
+ * @write_lock: Lock to serialize access when writing data
+ * @rust_private_data: Private data for the rust abstraction. This should
+ * not be used by the C drivers.
*/
struct serdev_device {
struct device dev;
@@ -47,6 +49,7 @@ struct serdev_device {
const struct serdev_device_ops *ops;
struct completion write_comp;
struct mutex write_lock;
+ void *rust_private_data;
};
static inline struct serdev_device *to_serdev_device(struct device *d)
--
2.52.0
^ permalink raw reply related
* [PATCH v4 1/4] rust: devres: return reference in `devres::register`
From: Markus Probst via B4 Relay @ 2026-04-11 15:10 UTC (permalink / raw)
To: Rob Herring, Greg Kroah-Hartman, Jiri Slaby, Miguel Ojeda,
Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg,
Alice Ryhl, Trevor Gross, Danilo Krummrich, Kari Argillander,
Rafael J. Wysocki, Viresh Kumar, Boqun Feng, David Airlie,
Simona Vetter, Boqun Feng
Cc: linux-serial, linux-kernel, rust-for-linux, linux-pm, driver-core,
dri-devel, Markus Probst
In-Reply-To: <20260411-rust_serdev-v4-0-845e960c6627@posteo.de>
From: Markus Probst <markus.probst@posteo.de>
Return the reference to the initialized data in the `devres::register`
function.
This is needed in a following commit (rust: add basic serial device bus
abstractions).
Signed-off-by: Markus Probst <markus.probst@posteo.de>
---
rust/kernel/cpufreq.rs | 3 ++-
rust/kernel/devres.rs | 15 +++++++++++++--
rust/kernel/drm/driver.rs | 3 ++-
3 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs
index f5adee48d40c..31bf7e685097 100644
--- a/rust/kernel/cpufreq.rs
+++ b/rust/kernel/cpufreq.rs
@@ -1052,7 +1052,8 @@ pub fn new_foreign_owned(dev: &Device<Bound>) -> Result
where
T: 'static,
{
- devres::register(dev, Self::new()?, GFP_KERNEL)
+ devres::register(dev, Self::new()?, GFP_KERNEL)?;
+ Ok(())
}
}
diff --git a/rust/kernel/devres.rs b/rust/kernel/devres.rs
index 6afe196be42c..f882bace8601 100644
--- a/rust/kernel/devres.rs
+++ b/rust/kernel/devres.rs
@@ -326,15 +326,26 @@ fn register_foreign<P>(dev: &Device<Bound>, data: P) -> Result
/// }
///
/// fn from_bound_context(dev: &Device<Bound>) -> Result {
-/// devres::register(dev, Registration::new(), GFP_KERNEL)
+/// devres::register(dev, Registration::new(), GFP_KERNEL)?;
+/// Ok(())
/// }
/// ```
-pub fn register<T, E>(dev: &Device<Bound>, data: impl PinInit<T, E>, flags: Flags) -> Result
+pub fn register<'a, T, E>(
+ dev: &'a Device<Bound>,
+ data: impl PinInit<T, E>,
+ flags: Flags,
+) -> Result<&'a T>
where
T: Send + 'static,
Error: From<E>,
{
let data = KBox::pin_init(data, flags)?;
+ let data_ptr = &raw const *data;
+
register_foreign(dev, data)
+ // SAFETY: `dev` is valid for the lifetime of 'a. As long as there is a reference to
+ // `Device<Bound>`, it is guaranteed that the device is not unbound and data has not been
+ // dropped. Thus `data_ptr` is also valid for the lifetime of 'a.
+ .map(|()| unsafe { &*data_ptr })
}
diff --git a/rust/kernel/drm/driver.rs b/rust/kernel/drm/driver.rs
index e09f977b5b51..51e0c7e30cc2 100644
--- a/rust/kernel/drm/driver.rs
+++ b/rust/kernel/drm/driver.rs
@@ -145,7 +145,8 @@ pub fn new_foreign_owned(
let reg = Registration::<T>::new(drm, flags)?;
- devres::register(dev, reg, GFP_KERNEL)
+ devres::register(dev, reg, GFP_KERNEL)?;
+ Ok(())
}
/// Returns a reference to the `Device` instance for this registration.
--
2.52.0
^ permalink raw reply related
* [PATCH v4 3/4] rust: add basic serial device bus abstractions
From: Markus Probst via B4 Relay @ 2026-04-11 15:10 UTC (permalink / raw)
To: Rob Herring, Greg Kroah-Hartman, Jiri Slaby, Miguel Ojeda,
Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg,
Alice Ryhl, Trevor Gross, Danilo Krummrich, Kari Argillander,
Rafael J. Wysocki, Viresh Kumar, Boqun Feng, David Airlie,
Simona Vetter, Boqun Feng
Cc: linux-serial, linux-kernel, rust-for-linux, linux-pm, driver-core,
dri-devel, Markus Probst
In-Reply-To: <20260411-rust_serdev-v4-0-845e960c6627@posteo.de>
From: Markus Probst <markus.probst@posteo.de>
Implement the basic serial device bus abstractions required to write a
serial device bus device driver with or without the need for initial device
data. This includes the following data structures:
The `serdev::Driver` trait represents the interface to the driver.
The `serdev::Device` abstraction represents a `struct serdev_device`.
In order to provide the Serdev specific parts to a generic
`driver::Registration` the `driver::RegistrationOps` trait is
implemented by `serdev::Adapter`.
Signed-off-by: Markus Probst <markus.probst@posteo.de>
---
drivers/tty/serdev/Kconfig | 7 +
rust/bindings/bindings_helper.h | 1 +
rust/helpers/helpers.c | 1 +
rust/helpers/serdev.c | 22 ++
rust/kernel/lib.rs | 2 +
rust/kernel/serdev.rs | 536 ++++++++++++++++++++++++++++++++++++++++
6 files changed, 569 insertions(+)
diff --git a/drivers/tty/serdev/Kconfig b/drivers/tty/serdev/Kconfig
index 46ae732bfc68..e6dfe949ad01 100644
--- a/drivers/tty/serdev/Kconfig
+++ b/drivers/tty/serdev/Kconfig
@@ -9,6 +9,13 @@ menuconfig SERIAL_DEV_BUS
Note that you typically also want to enable TTY port controller support.
+config RUST_SERIAL_DEV_BUS_ABSTRACTIONS
+ bool "Rust Serial device bus abstractions"
+ depends on RUST
+ select SERIAL_DEV_BUS
+ help
+ This enables the Rust abstraction for the serial device bus API.
+
if SERIAL_DEV_BUS
config SERIAL_DEV_CTRL_TTYPORT
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 083cc44aa952..ab521ba42673 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -80,6 +80,7 @@
#include <linux/regulator/consumer.h>
#include <linux/sched.h>
#include <linux/security.h>
+#include <linux/serdev.h>
#include <linux/slab.h>
#include <linux/sys_soc.h>
#include <linux/task_work.h>
diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
index a3c42e51f00a..9b87e9591cfd 100644
--- a/rust/helpers/helpers.c
+++ b/rust/helpers/helpers.c
@@ -53,6 +53,7 @@
#include "regulator.c"
#include "scatterlist.c"
#include "security.c"
+#include "serdev.c"
#include "signal.c"
#include "slab.c"
#include "spinlock.c"
diff --git a/rust/helpers/serdev.c b/rust/helpers/serdev.c
new file mode 100644
index 000000000000..c52b78ca3fc7
--- /dev/null
+++ b/rust/helpers/serdev.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/serdev.h>
+
+__rust_helper
+void rust_helper_serdev_device_driver_unregister(struct serdev_device_driver *sdrv)
+{
+ serdev_device_driver_unregister(sdrv);
+}
+
+__rust_helper
+void rust_helper_serdev_device_put(struct serdev_device *serdev)
+{
+ serdev_device_put(serdev);
+}
+
+__rust_helper
+void rust_helper_serdev_device_set_client_ops(struct serdev_device *serdev,
+ const struct serdev_device_ops *ops)
+{
+ serdev_device_set_client_ops(serdev, ops);
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index d93292d47420..5107c9c1be07 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -144,6 +144,8 @@
pub mod scatterlist;
pub mod security;
pub mod seq_file;
+#[cfg(CONFIG_RUST_SERIAL_DEV_BUS_ABSTRACTIONS)]
+pub mod serdev;
pub mod sizes;
pub mod slice;
#[cfg(CONFIG_SOC_BUS)]
diff --git a/rust/kernel/serdev.rs b/rust/kernel/serdev.rs
new file mode 100644
index 000000000000..d9fea4bd4439
--- /dev/null
+++ b/rust/kernel/serdev.rs
@@ -0,0 +1,536 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Abstractions for the serial device bus.
+//!
+//! C header: [`include/linux/serdev.h`](srctree/include/linux/serdev.h)
+
+use crate::{
+ acpi,
+ device,
+ devres,
+ driver,
+ error::{
+ from_result,
+ to_result,
+ VTABLE_DEFAULT_ERROR, //
+ },
+ of,
+ prelude::*,
+ sync::Completion,
+ time::{
+ msecs_to_jiffies,
+ Jiffies,
+ Msecs, //
+ },
+ types::{
+ AlwaysRefCounted,
+ Opaque, //
+ }, //
+};
+
+use core::{
+ cell::UnsafeCell,
+ marker::PhantomData,
+ mem::offset_of,
+ num::NonZero,
+ ptr::NonNull, //
+};
+
+/// Parity bit to use with a serial device.
+#[repr(u32)]
+pub enum Parity {
+ /// No parity bit.
+ None = bindings::serdev_parity_SERDEV_PARITY_NONE,
+ /// Even partiy.
+ Even = bindings::serdev_parity_SERDEV_PARITY_EVEN,
+ /// Odd parity.
+ Odd = bindings::serdev_parity_SERDEV_PARITY_ODD,
+}
+
+/// Timeout in Jiffies.
+pub enum Timeout {
+ /// Wait for a specific amount of [`Jiffies`].
+ Jiffies(NonZero<Jiffies>),
+ /// Wait for a specific amount of [`Msecs`].
+ Milliseconds(NonZero<Msecs>),
+ /// Wait as long as possible.
+ ///
+ /// This is equivalent to [`kernel::task::MAX_SCHEDULE_TIMEOUT`].
+ Max,
+}
+
+impl Timeout {
+ fn into_jiffies(self) -> isize {
+ match self {
+ Self::Jiffies(value) => value.get().try_into().unwrap_or_default(),
+ Self::Milliseconds(value) => {
+ msecs_to_jiffies(value.get()).try_into().unwrap_or_default()
+ }
+ Self::Max => 0,
+ }
+ }
+}
+
+/// An adapter for the registration of serial device bus device drivers.
+pub struct Adapter<T: Driver>(T);
+
+// SAFETY:
+// - `bindings::serdev_device_driver` is a C type declared as `repr(C)`.
+// - `Drvdata<T>` is the type of the driver's device private data.
+// - `struct serdev_device_driver` embeds a `struct device_driver`.
+// - `DEVICE_DRIVER_OFFSET` is the correct byte offset to the embedded `struct device_driver`.
+unsafe impl<T: Driver + 'static> driver::DriverLayout for Adapter<T> {
+ type DriverType = bindings::serdev_device_driver;
+ type DriverData = T;
+ const DEVICE_DRIVER_OFFSET: usize = core::mem::offset_of!(Self::DriverType, driver);
+}
+
+// SAFETY: A call to `unregister` for a given instance of `DriverType` is guaranteed to be valid if
+// a preceding call to `register` has been successful.
+unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
+ unsafe fn register(
+ sdrv: &Opaque<Self::DriverType>,
+ name: &'static CStr,
+ module: &'static ThisModule,
+ ) -> Result {
+ let of_table = match T::OF_ID_TABLE {
+ Some(table) => table.as_ptr(),
+ None => core::ptr::null(),
+ };
+
+ let acpi_table = match T::ACPI_ID_TABLE {
+ Some(table) => table.as_ptr(),
+ None => core::ptr::null(),
+ };
+
+ // SAFETY: It's safe to set the fields of `struct serdev_device_driver` on initialization.
+ unsafe {
+ (*sdrv.get()).driver.name = name.as_char_ptr();
+ (*sdrv.get()).probe = Some(Self::probe_callback);
+ (*sdrv.get()).remove = Some(Self::remove_callback);
+ (*sdrv.get()).driver.of_match_table = of_table;
+ (*sdrv.get()).driver.acpi_match_table = acpi_table;
+ }
+
+ // SAFETY: `sdrv` is guaranteed to be a valid `DriverType`.
+ to_result(unsafe { bindings::__serdev_device_driver_register(sdrv.get(), module.0) })
+ }
+
+ unsafe fn unregister(sdrv: &Opaque<Self::DriverType>) {
+ // SAFETY: `sdrv` is guaranteed to be a valid `DriverType`.
+ unsafe { bindings::serdev_device_driver_unregister(sdrv.get()) };
+ }
+}
+
+#[pin_data]
+struct PrivateData {
+ #[pin]
+ probe_complete: Completion,
+ error: UnsafeCell<bool>,
+}
+
+impl<T: Driver + 'static> Adapter<T> {
+ const OPS: &'static bindings::serdev_device_ops = &bindings::serdev_device_ops {
+ receive_buf: if T::HAS_RECEIVE {
+ Some(Self::receive_buf_callback)
+ } else {
+ None
+ },
+ write_wakeup: Some(bindings::serdev_device_write_wakeup),
+ };
+
+ extern "C" fn probe_callback(sdev: *mut bindings::serdev_device) -> kernel::ffi::c_int {
+ // SAFETY: The serial device bus only ever calls the probe callback with a valid pointer to
+ // a `struct serdev_device`.
+ //
+ // INVARIANT: `sdev` is valid for the duration of `probe_callback()`.
+ let sdev = unsafe { &*sdev.cast::<Device<device::CoreInternal>>() };
+ let id_info = <Self as driver::Adapter>::id_info(sdev.as_ref());
+
+ from_result(|| {
+ let private_data = devres::register(
+ sdev.as_ref(),
+ try_pin_init!(PrivateData {
+ probe_complete <- Completion::new(),
+ error: false.into(),
+ }),
+ GFP_KERNEL,
+ )?;
+
+ // SAFETY: `sdev.as_raw()` is guaranteed to be a valid pointer to `serdev_device`.
+ unsafe {
+ (*sdev.as_raw()).rust_private_data =
+ (&raw const *private_data).cast::<c_void>().cast_mut()
+ };
+
+ // SAFETY: `sdev.as_raw()` is guaranteed to be a valid pointer to `serdev_device`.
+ unsafe { bindings::serdev_device_set_client_ops(sdev.as_raw(), Self::OPS) };
+
+ // SAFETY: The serial device bus only ever calls the probe callback with a valid pointer
+ // to a `serdev_device`.
+ to_result(unsafe {
+ bindings::devm_serdev_device_open(sdev.as_ref().as_raw(), sdev.as_raw())
+ })?;
+
+ let data = T::probe(sdev, id_info);
+ let result = sdev.as_ref().set_drvdata(data);
+
+ // SAFETY: We have exclusive access to `private_data.error`.
+ unsafe { *private_data.error.get() = result.is_err() };
+
+ private_data.probe_complete.complete_all();
+
+ result.map(|()| 0)
+ })
+ }
+
+ extern "C" fn remove_callback(sdev: *mut bindings::serdev_device) {
+ // SAFETY: The serial device bus only ever calls the remove callback with a valid pointer
+ // to a `struct serdev_device`.
+ //
+ // INVARIANT: `sdev` is valid for the duration of `remove_callback()`.
+ let sdev = unsafe { &*sdev.cast::<Device<device::CoreInternal>>() };
+
+ // SAFETY: `remove_callback` is only ever called after a successful call to
+ // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
+ // and stored a `Pin<KBox<T>>`.
+ let data = unsafe { sdev.as_ref().drvdata_borrow::<T>() };
+
+ T::unbind(sdev, data);
+ }
+
+ extern "C" fn receive_buf_callback(
+ sdev: *mut bindings::serdev_device,
+ buf: *const u8,
+ length: usize,
+ ) -> usize {
+ // SAFETY: The serial device bus only ever calls the receive buf callback with a valid
+ // pointer to a `struct serdev_device`.
+ //
+ // INVARIANT: `sdev` is valid for the duration of `receive_buf_callback()`.
+ let sdev = unsafe { &*sdev.cast::<Device<device::CoreInternal>>() };
+
+ // SAFETY:
+ // - The serial device bus only ever calls the receive buf callback with a valid pointer to
+ // a `struct serdev_device`.
+ // - `receive_buf_callback` is only ever called after a successful call to
+ // `probe_callback`, hence it's guaranteed that `sdev.private_data` is a pointer
+ // to a valid `PrivateData`.
+ let private_data = unsafe { &*(*sdev.as_raw()).rust_private_data.cast::<PrivateData>() };
+
+ private_data.probe_complete.wait_for_completion();
+
+ // SAFETY: No one has exclusive access to `private_data.error`.
+ if unsafe { *private_data.error.get() } {
+ return length;
+ }
+
+ // SAFETY: `receive_buf_callback` is only ever called after a successful call to
+ // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
+ // and stored a `Pin<KBox<T>>`.
+ let data = unsafe { sdev.as_ref().drvdata_borrow::<T>() };
+
+ // SAFETY: `buf` is guaranteed to be non-null and has the size of `length`.
+ let buf = unsafe { core::slice::from_raw_parts(buf, length) };
+
+ T::receive(sdev, data, buf)
+ }
+}
+
+impl<T: Driver + 'static> driver::Adapter for Adapter<T> {
+ type IdInfo = T::IdInfo;
+
+ fn of_id_table() -> Option<of::IdTable<Self::IdInfo>> {
+ T::OF_ID_TABLE
+ }
+
+ fn acpi_id_table() -> Option<acpi::IdTable<Self::IdInfo>> {
+ T::ACPI_ID_TABLE
+ }
+}
+
+/// Declares a kernel module that exposes a single serial device bus device driver.
+///
+/// # Examples
+///
+/// ```ignore
+/// kernel::module_serdev_device_driver! {
+/// type: MyDriver,
+/// name: "Module name",
+/// authors: ["Author name"],
+/// description: "Description",
+/// license: "GPL v2",
+/// }
+/// ```
+#[macro_export]
+macro_rules! module_serdev_device_driver {
+ ($($f:tt)*) => {
+ $crate::module_driver!(<T>, $crate::serdev::Adapter<T>, { $($f)* });
+ };
+}
+
+/// The serial device bus device driver trait.
+///
+/// Drivers must implement this trait in order to get a serial device bus device driver registered.
+///
+/// # Examples
+///
+///```
+/// # use kernel::{
+/// acpi,
+/// bindings,
+/// device::{
+/// Bound,
+/// Core, //
+/// },
+/// of,
+/// serdev, //
+/// };
+///
+/// struct MyDriver;
+///
+/// kernel::of_device_table!(
+/// OF_TABLE,
+/// MODULE_OF_TABLE,
+/// <MyDriver as serdev::Driver>::IdInfo,
+/// [
+/// (of::DeviceId::new(c"test,device"), ())
+/// ]
+/// );
+///
+/// kernel::acpi_device_table!(
+/// ACPI_TABLE,
+/// MODULE_ACPI_TABLE,
+/// <MyDriver as serdev::Driver>::IdInfo,
+/// [
+/// (acpi::DeviceId::new(c"LNUXBEEF"), ())
+/// ]
+/// );
+///
+/// #[vtable]
+/// impl serdev::Driver for MyDriver {
+/// type IdInfo = ();
+/// const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE);
+/// const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = Some(&ACPI_TABLE);
+///
+/// fn probe(
+/// sdev: &serdev::Device<Core>,
+/// _id_info: Option<&Self::IdInfo>,
+/// ) -> impl PinInit<Self, Error> {
+/// sdev.set_baudrate(115200);
+/// sdev.write_all(b"Hello\n", serdev::Timeout::Max)?;
+/// Ok(MyDriver)
+/// }
+/// }
+///```
+#[vtable]
+pub trait Driver: Send {
+ /// The type holding driver private data about each device id supported by the driver.
+ // TODO: Use associated_type_defaults once stabilized:
+ //
+ // ```
+ // type IdInfo: 'static = ();
+ // ```
+ type IdInfo: 'static;
+
+ /// The table of OF device ids supported by the driver.
+ const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = None;
+
+ /// The table of ACPI device ids supported by the driver.
+ const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = None;
+
+ /// Serial device bus device driver probe.
+ ///
+ /// Called when a new serial device bus device is added or discovered.
+ /// Implementers should attempt to initialize the device here.
+ fn probe(
+ sdev: &Device<device::Core>,
+ id_info: Option<&Self::IdInfo>,
+ ) -> impl PinInit<Self, Error>;
+
+ /// Serial device bus device driver unbind.
+ ///
+ /// Called when a [`Device`] is unbound from its bound [`Driver`]. Implementing this callback
+ /// is optional.
+ ///
+ /// This callback serves as a place for drivers to perform teardown operations that require a
+ /// `&Device<Core>` or `&Device<Bound>` reference. For instance.
+ ///
+ /// Otherwise, release operations for driver resources should be performed in `Self::drop`.
+ fn unbind(sdev: &Device<device::Core>, this: Pin<&Self>) {
+ let _ = (sdev, this);
+ }
+
+ /// Serial device bus device data receive callback.
+ ///
+ /// Called when data got received from device.
+ ///
+ /// Returns the number of bytes accepted.
+ fn receive(sdev: &Device<device::Bound>, this: Pin<&Self>, data: &[u8]) -> usize {
+ let _ = (sdev, this, data);
+ build_error!(VTABLE_DEFAULT_ERROR)
+ }
+}
+
+/// The serial device bus device representation.
+///
+/// This structure represents the Rust abstraction for a C `struct serdev_device`. The
+/// implementation abstracts the usage of an already existing C `struct serdev_device` within Rust
+/// code that we get passed from the C side.
+///
+/// # Invariants
+///
+/// A [`Device`] instance represents a valid `struct serdev_device` created by the C portion of
+/// the kernel.
+#[repr(transparent)]
+pub struct Device<Ctx: device::DeviceContext = device::Normal>(
+ Opaque<bindings::serdev_device>,
+ PhantomData<Ctx>,
+);
+
+impl<Ctx: device::DeviceContext> Device<Ctx> {
+ fn as_raw(&self) -> *mut bindings::serdev_device {
+ self.0.get()
+ }
+}
+
+impl Device<device::Bound> {
+ /// Set the baudrate in bits per second.
+ ///
+ /// Common baudrates are 115200, 9600, 19200, 57600, 4800.
+ ///
+ /// Use [`Device::write_flush`] before calling this if you have written data prior to this call.
+ pub fn set_baudrate(&self, speed: u32) -> Result<(), u32> {
+ // SAFETY: `self.as_raw()` is guaranteed to be a pointer to a valid `serdev_device`.
+ let ret = unsafe { bindings::serdev_device_set_baudrate(self.as_raw(), speed) };
+ if ret == speed {
+ Ok(())
+ } else {
+ Err(ret)
+ }
+ }
+
+ /// Set if flow control should be enabled.
+ ///
+ /// Use [`Device::write_flush`] before calling this if you have written data prior to this call.
+ pub fn set_flow_control(&self, enable: bool) {
+ // SAFETY: `self.as_raw()` is guaranteed to be a pointer to a valid `serdev_device`.
+ unsafe { bindings::serdev_device_set_flow_control(self.as_raw(), enable) };
+ }
+
+ /// Set parity to use.
+ ///
+ /// Use [`Device::write_flush`] before calling this if you have written data prior to this call.
+ pub fn set_parity(&self, parity: Parity) -> Result {
+ // SAFETY: `self.as_raw()` is guaranteed to be a pointer to a valid `serdev_device`.
+ to_result(unsafe { bindings::serdev_device_set_parity(self.as_raw(), parity as u32) })
+ }
+
+ /// Write data to the serial device until the controller has accepted all the data or has
+ /// been interrupted by a timeout or signal.
+ ///
+ /// Note that any accepted data has only been buffered by the controller. Use
+ /// [ Device::wait_until_sent`] to make sure the controller write buffer has actually been
+ /// emptied.
+ ///
+ /// Returns the number of bytes written (less than `data.len()` if interrupted).
+ /// [`kernel::error::code::ETIMEDOUT`] or [`kernel::error::code::ERESTARTSYS`] if interrupted
+ /// before any bytes were written.
+ pub fn write_all(&self, data: &[u8], timeout: Timeout) -> Result<usize> {
+ // SAFETY:
+ // - `self.as_raw()` is guaranteed to be a pointer to a valid `serdev_device`.
+ // - `data.as_ptr()` is guaranteed to be a valid array pointer with the size of
+ // `data.len()`.
+ let ret = unsafe {
+ bindings::serdev_device_write(
+ self.as_raw(),
+ data.as_ptr(),
+ data.len(),
+ timeout.into_jiffies(),
+ )
+ };
+ // CAST: negative return values are guaranteed to be between `-MAX_ERRNO` and `-1`,
+ // which always fit into a `i32`.
+ to_result(ret as i32).map(|()| ret.unsigned_abs())
+ }
+
+ /// Write data to the serial device.
+ ///
+ /// If you want to write until the controller has accepted all the data, use
+ /// [`Device::write_all`].
+ ///
+ /// Note that any accepted data has only been buffered by the controller. Use
+ /// [ Device::wait_until_sent`] to make sure the controller write buffer has actually been
+ /// emptied.
+ ///
+ /// Returns the number of bytes written (less than `data.len()` if not enough room in the
+ /// write buffer).
+ pub fn write(&self, data: &[u8]) -> Result<u32> {
+ // SAFETY:
+ // - `self.as_raw()` is guaranteed to be a pointer to a valid `serdev_device`.
+ // - `data.as_ptr()` is guaranteed to be a valid array pointer with the size of
+ // `data.len()`.
+ let ret =
+ unsafe { bindings::serdev_device_write_buf(self.as_raw(), data.as_ptr(), data.len()) };
+
+ to_result(ret as i32).map(|()| ret.unsigned_abs())
+ }
+
+ /// Send data to the serial device immediately.
+ ///
+ /// Note that this doesn't guarantee that the data has been transmitted.
+ /// Use [`Device::wait_until_sent`] for this purpose.
+ pub fn write_flush(&self) {
+ // SAFETY: `self.as_raw()` is guaranteed to be a pointer to a valid `serdev_device`.
+ unsafe { bindings::serdev_device_write_flush(self.as_raw()) };
+ }
+
+ /// Wait for the data to be sent.
+ ///
+ /// After this function, the write buffer of the controller should be empty.
+ pub fn wait_until_sent(&self, timeout: Timeout) {
+ // SAFETY: `self.as_raw()` is guaranteed to be a pointer to a valid `serdev_device`.
+ unsafe { bindings::serdev_device_wait_until_sent(self.as_raw(), timeout.into_jiffies()) };
+ }
+}
+
+// SAFETY: `serdev::Device` is a transparent wrapper of `struct serdev_device`.
+// The offset is guaranteed to point to a valid device field inside `serdev::Device`.
+unsafe impl<Ctx: device::DeviceContext> device::AsBusDevice<Ctx> for Device<Ctx> {
+ const OFFSET: usize = offset_of!(bindings::serdev_device, dev);
+}
+
+// SAFETY: `Device` is a transparent wrapper of a type that doesn't depend on `Device`'s generic
+// argument.
+kernel::impl_device_context_deref!(unsafe { Device });
+kernel::impl_device_context_into_aref!(Device);
+
+// SAFETY: Instances of `Device` are always reference-counted.
+unsafe impl AlwaysRefCounted for Device {
+ fn inc_ref(&self) {
+ self.as_ref().inc_ref();
+ }
+
+ unsafe fn dec_ref(obj: NonNull<Self>) {
+ // SAFETY: The safety requirements guarantee that the refcount is non-zero.
+ unsafe { bindings::serdev_device_put(obj.cast().as_ptr()) }
+ }
+}
+
+impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> {
+ fn as_ref(&self) -> &device::Device<Ctx> {
+ // SAFETY: By the type invariant of `Self`, `self.as_raw()` is a pointer to a valid
+ // `struct serdev_device`.
+ let dev = unsafe { &raw mut (*self.as_raw()).dev };
+
+ // SAFETY: `dev` points to a valid `struct device`.
+ unsafe { device::Device::from_raw(dev) }
+ }
+}
+
+// SAFETY: A `Device` is always reference-counted and can be released from any thread.
+unsafe impl Send for Device {}
+
+// SAFETY: `Device` can be shared among threads because all methods of `Device`
+// (i.e. `Device<Normal>) are thread safe.
+unsafe impl Sync for Device {}
--
2.52.0
^ permalink raw reply related
page: next (older) | prev (newer) | latest
- recent:[subjects (threaded)|topics (new)|topics (active)]
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox