* [PATCH v2 1/2] serial: pl010: Move uart_register_driver call to device probe
2017-04-20 12:12 [PATCH v2 0/2] Move uart_register_driver call to device probe for pl010 and sh-sci Sjoerd Simons
@ 2017-04-20 12:13 ` Sjoerd Simons
2017-04-20 12:13 ` [PATCH v2 2/2] serial: sh-sci: " Sjoerd Simons
1 sibling, 0 replies; 3+ messages in thread
From: Sjoerd Simons @ 2017-04-20 12:13 UTC (permalink / raw)
To: linux-serial
Cc: linux-renesas-soc, Greg Kroah-Hartman, linux-kernel, Russell King,
Jiri Slaby
uart_register_driver call binds the driver to a specific device
node through tty_register_driver call. This should typically
happen during device probe call.
In a multiplatform scenario, it is possible that multiple serial
drivers are part of the kernel. Currently the driver registration fails
if multiple serial drivers with overlapping major/minor numbers are
included.
Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
---
Changes in v2:
- Add locking to prevent issues when two probes run in parallel
drivers/tty/serial/amba-pl010.c | 31 +++++++++++++++++++++----------
1 file changed, 21 insertions(+), 10 deletions(-)
diff --git a/drivers/tty/serial/amba-pl010.c b/drivers/tty/serial/amba-pl010.c
index f2f251075109..24180adb1cbb 100644
--- a/drivers/tty/serial/amba-pl010.c
+++ b/drivers/tty/serial/amba-pl010.c
@@ -697,6 +697,7 @@ static struct console amba_console = {
#define AMBA_CONSOLE NULL
#endif
+static DEFINE_MUTEX(amba_reg_lock);
static struct uart_driver amba_reg = {
.owner = THIS_MODULE,
.driver_name = "ttyAM",
@@ -749,6 +750,19 @@ static int pl010_probe(struct amba_device *dev, const struct amba_id *id)
amba_ports[i] = uap;
amba_set_drvdata(dev, uap);
+
+ mutex_lock(&amba_reg_lock);
+ if (!amba_reg.state) {
+ ret = uart_register_driver(&amba_reg);
+ if (ret < 0) {
+ mutex_unlock(&amba_reg_lock);
+ dev_err(uap->port.dev,
+ "Failed to register AMBA-PL010 driver\n");
+ return ret;
+ }
+ }
+ mutex_unlock(&amba_reg_lock);
+
ret = uart_add_one_port(&amba_reg, &uap->port);
if (ret)
amba_ports[i] = NULL;
@@ -760,12 +774,18 @@ static int pl010_remove(struct amba_device *dev)
{
struct uart_amba_port *uap = amba_get_drvdata(dev);
int i;
+ bool busy = false;
uart_remove_one_port(&amba_reg, &uap->port);
for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
if (amba_ports[i] == uap)
amba_ports[i] = NULL;
+ else if (amba_ports[i])
+ busy = true;
+
+ if (!busy)
+ uart_unregister_driver(&amba_reg);
return 0;
}
@@ -816,23 +836,14 @@ static struct amba_driver pl010_driver = {
static int __init pl010_init(void)
{
- int ret;
-
printk(KERN_INFO "Serial: AMBA driver\n");
- ret = uart_register_driver(&amba_reg);
- if (ret == 0) {
- ret = amba_driver_register(&pl010_driver);
- if (ret)
- uart_unregister_driver(&amba_reg);
- }
- return ret;
+ return amba_driver_register(&pl010_driver);
}
static void __exit pl010_exit(void)
{
amba_driver_unregister(&pl010_driver);
- uart_unregister_driver(&amba_reg);
}
module_init(pl010_init);
--
2.11.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH v2 2/2] serial: sh-sci: Move uart_register_driver call to device probe
2017-04-20 12:12 [PATCH v2 0/2] Move uart_register_driver call to device probe for pl010 and sh-sci Sjoerd Simons
2017-04-20 12:13 ` [PATCH v2 1/2] serial: pl010: Move uart_register_driver call to device probe Sjoerd Simons
@ 2017-04-20 12:13 ` Sjoerd Simons
1 sibling, 0 replies; 3+ messages in thread
From: Sjoerd Simons @ 2017-04-20 12:13 UTC (permalink / raw)
To: linux-serial
Cc: linux-renesas-soc, Greg Kroah-Hartman, linux-kernel, Jiri Slaby
uart_register_driver call binds the driver to a specific device
node through tty_register_driver call. This should typically
happen during device probe call.
In a multiplatform scenario, it is possible that multiple serial
drivers are part of the kernel. Currently the driver registration fails
if multiple serial drivers with overlapping major/minor numbers are
included.
Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
---
Changes in v2:
- Add locking to prevent issues when two probes run in parallel
drivers/tty/serial/sh-sci.c | 26 +++++++++++++++-----------
1 file changed, 15 insertions(+), 11 deletions(-)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 9a47cc4f16a2..f23254add9a7 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -2935,6 +2935,7 @@ static inline int sci_probe_earlyprintk(struct platform_device *pdev)
static const char banner[] __initconst = "SuperH (H)SCI(F) driver initialized";
+static DEFINE_MUTEX(sci_uart_registration_lock);
static struct uart_driver sci_uart_driver = {
.owner = THIS_MODULE,
.driver_name = "sci",
@@ -3063,6 +3064,16 @@ static int sci_probe_single(struct platform_device *dev,
return -EINVAL;
}
+ mutex_lock(&sci_uart_registration_lock);
+ if (!sci_uart_driver.state) {
+ ret = uart_register_driver(&sci_uart_driver);
+ if (ret) {
+ mutex_unlock(&sci_uart_registration_lock);
+ return ret;
+ }
+ }
+ mutex_unlock(&sci_uart_registration_lock);
+
ret = sci_init_single(dev, sciport, index, p, false);
if (ret)
return ret;
@@ -3186,24 +3197,17 @@ static struct platform_driver sci_driver = {
static int __init sci_init(void)
{
- int ret;
-
pr_info("%s\n", banner);
- ret = uart_register_driver(&sci_uart_driver);
- if (likely(ret == 0)) {
- ret = platform_driver_register(&sci_driver);
- if (unlikely(ret))
- uart_unregister_driver(&sci_uart_driver);
- }
-
- return ret;
+ return platform_driver_register(&sci_driver);
}
static void __exit sci_exit(void)
{
platform_driver_unregister(&sci_driver);
- uart_unregister_driver(&sci_uart_driver);
+
+ if (sci_uart_driver.state)
+ uart_unregister_driver(&sci_uart_driver);
}
#ifdef CONFIG_SERIAL_SH_SCI_CONSOLE
--
2.11.0
^ permalink raw reply related [flat|nested] 3+ messages in thread