* [patch v7 3/4] Documentation: jtag: Add bindings for Aspeed SoC 24xx and 25xx families JTAG master driver
From: Oleksandr Shamray @ 2017-09-01 16:06 UTC (permalink / raw)
To: gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r, arnd-r2nGTMty4D4
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
devicetree-u79uwXL29TY76Z2rM5mHXA, openbmc-uLR06cmDAlY/bJ5BZ2RsiQ,
joel-U3u1mxZcP9KHXe+LvDLADg, jiri-rHqAuBHg3fBzbRFIqnYvSA,
tklauser-93Khv+1bN0NyDzI6CaY1VQ,
linux-serial-u79uwXL29TY76Z2rM5mHXA, mec-WqBc5aa1uDFeoWH0uzbU5w,
vadimp-45czdsxZ+A5DPfheJLI6IQ,
system-sw-low-level-VPRAkNaXOzVWk0Htik3J/w,
robh+dt-DgEjT+Ai2ygdnm+yROfE0A,
openocd-devel-owner-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f,
linux-api-u79uwXL29TY76Z2rM5mHXA, davem-fT/PcQaiUtIeIZ0/mPfg9Q,
mchehab-DgEjT+Ai2ygdnm+yROfE0A, Oleksandr Shamray, Jiri Pirko
In-Reply-To: <1504281966-6199-1-git-send-email-oleksandrs-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
It has been tested on Mellanox system with BMC equipped with
Aspeed 2520 SoC for programming CPLD devices.
Signed-off-by: Oleksandr Shamray <oleksandrs-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Signed-off-by: Jiri Pirko <jiri-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
V6->v7
Comments pointed by Tobias Klauser <tklauser-93Khv+1bN0NyDzI6CaY1VQ@public.gmane.org>
- Fix spell "Doccumentation" -> "Documentation"
v5->v6
Comments pointed by Tobias Klauser <tklauser-93Khv+1bN0NyDzI6CaY1VQ@public.gmane.org>
- Small nit: s/documentation/Documentation/
v4->v5
V3->v4
Comments pointed by Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
- delete unnecessary "status" and "reg-shift" descriptions in
bndings file
v2->v3
Comments pointed by Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
- split Aspeed jtag driver and binding to sepatrate patches
- delete unnecessary "status" and "reg-shift" descriptions in
bndings file
---
.../devicetree/bindings/jtag/aspeed-jtag.txt | 18 ++++++++++++++++++
MAINTAINERS | 1 +
2 files changed, 19 insertions(+), 0 deletions(-)
create mode 100644 Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
diff --git a/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt b/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
new file mode 100644
index 0000000..f4ded49
--- /dev/null
+++ b/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
@@ -0,0 +1,18 @@
+Aspeed JTAG driver for ast2400 and ast2500 SoC
+
+Required properties:
+- compatible: Should be one of
+ - "aspeed,aspeed2400-jtag"
+ - "aspeed,aspeed2500-jtag"
+- reg contains the offset and length of the JTAG memory
+ region
+- clocks root clock of bus, should reference the APB clock
+- interrupts should contain JTAG controller interrupt
+
+Example:
+jtag: jtag@1e6e4000 {
+ compatible = "aspeed,aspeed2500-jtag";
+ reg = <0x1e6e4000 0x1c>;
+ clocks = <&clk_apb>;
+ interrupts = <43>;
+};
diff --git a/MAINTAINERS b/MAINTAINERS
index 141aeaf..bfdfa94 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7299,6 +7299,7 @@ S: Maintained
F: include/linux/jtag.h
F: include/uapi/linux/jtag.h
F: drivers/jtag/
+F: Documentation/devicetree/bindings/jtag/
K10TEMP HARDWARE MONITORING DRIVER
M: Clemens Ladisch <clemens-P6GI/4k7KOmELgA04lAiVw@public.gmane.org>
--
1.7.1
--
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^ permalink raw reply related
* [patch v7 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver
From: Oleksandr Shamray @ 2017-09-01 16:06 UTC (permalink / raw)
To: gregkh, arnd
Cc: linux-kernel, linux-arm-kernel, devicetree, openbmc, joel, jiri,
tklauser, linux-serial, mec, vadimp, system-sw-low-level, robh+dt,
openocd-devel-owner, linux-api, davem, mchehab, Oleksandr Shamray,
Jiri Pirko
In-Reply-To: <1504281966-6199-1-git-send-email-oleksandrs@mellanox.com>
Driver adds support of Aspeed 2500/2400 series SOC JTAG master controller.
Driver implements the following jtag ops:
- freq_get;
- freq_set;
- status_get;
- idle;
- xfer;
It has been tested on Mellanox system with BMC equipped with
Aspeed 2520 SoC for programming CPLD devices.
Signed-off-by: Oleksandr Shamray <oleksandrs@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
---
v6->v7
Notifications from kbuild test robot <lkp@intel.com>
- Add include <linux/types.h> to jtag-asapeed.c
v5->v6
v4->v5
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- Added HAS_IOMEM dependence in Kconfig to avoid
"undefined reference to `devm_ioremap_resource'" error,
because in some arch this not supported
v3->v4
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- change transaction pointer tdio type to __u64
- change internal status type from enum to __u32
v2->v3
v1->v2
Comments pointed by Greg KH <gregkh@linuxfoundation.org>
- change license type from GPLv2/BSD to GPLv2
Comments pointed by Neil Armstrong <narmstrong@baylibre.com>
- Add clk_prepare_enable/clk_disable_unprepare in clock init/deinit
- Change .compatible to soc-specific compatible names
aspeed,aspeed4000-jtag/aspeed5000-jtag
- Added dt-bindings
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- Reorder functions and removed the forward declarations
- Add static const qualifier to state machine states transitions
- Change .compatible to soc-specific compatible names
aspeed,aspeed4000-jtag/aspeed5000-jtag
- Add dt-bindings
Comments pointed by Randy Dunlap <rdunlap@infradead.org>
- Change module name jtag-aspeed in description in Kconfig
Comments pointed by kbuild test robot <lkp@intel.com>
- Remove invalid include <asm/mach-types.h>
- add resource_size instead of calculation
---
drivers/jtag/Kconfig | 13 +
drivers/jtag/Makefile | 1 +
drivers/jtag/jtag-aspeed.c | 773 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 787 insertions(+), 0 deletions(-)
create mode 100644 drivers/jtag/jtag-aspeed.c
diff --git a/drivers/jtag/Kconfig b/drivers/jtag/Kconfig
index 0fad1a3..098beb0 100644
--- a/drivers/jtag/Kconfig
+++ b/drivers/jtag/Kconfig
@@ -14,3 +14,16 @@ menuconfig JTAG
To compile this driver as a module, choose M here: the module will
be called jtag.
+
+menuconfig JTAG_ASPEED
+ tristate "Aspeed SoC JTAG controller support"
+ depends on JTAG && HAS_IOMEM
+ ---help---
+ This provides a support for Aspeed JTAG device, equipped on
+ Aspeed SoC 24xx and 25xx families. Drivers allows programming
+ of hardware devices, connected to SoC through the JTAG interface.
+
+ If you want this support, you should say Y here.
+
+ To compile this driver as a module, choose M here: the module will
+ be called jtag-aspeed.
diff --git a/drivers/jtag/Makefile b/drivers/jtag/Makefile
index af37493..04a855e 100644
--- a/drivers/jtag/Makefile
+++ b/drivers/jtag/Makefile
@@ -1 +1,2 @@
obj-$(CONFIG_JTAG) += jtag.o
+obj-$(CONFIG_JTAG_ASPEED) += jtag-aspeed.o
diff --git a/drivers/jtag/jtag-aspeed.c b/drivers/jtag/jtag-aspeed.c
new file mode 100644
index 0000000..017d96e
--- /dev/null
+++ b/drivers/jtag/jtag-aspeed.c
@@ -0,0 +1,773 @@
+/*
+ * drivers/jtag/jtag.c
+ *
+ * Copyright (c) 2017 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2017 Oleksandr Shamray <oleksandrs@mellanox.com>
+ *
+ * Released under the GPLv2 only.
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/jtag.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <uapi/linux/jtag.h>
+
+#define ASPEED_JTAG_DATA 0x00
+#define ASPEED_JTAG_INST 0x04
+#define ASPEED_JTAG_CTRL 0x08
+#define ASPEED_JTAG_ISR 0x0C
+#define ASPEED_JTAG_SW 0x10
+#define ASPEED_JTAG_TCK 0x14
+#define ASPEED_JTAG_EC 0x18
+
+#define ASPEED_JTAG_DATA_MSB 0x01
+#define ASPEED_JTAG_DATA_CHUNK_SIZE 0x20
+
+/* ASPEED_JTAG_CTRL: Engine Control */
+#define ASPEED_JTAG_CTL_ENG_EN BIT(31)
+#define ASPEED_JTAG_CTL_ENG_OUT_EN BIT(30)
+#define ASPEED_JTAG_CTL_FORCE_TMS BIT(29)
+#define ASPEED_JTAG_CTL_INST_LEN(x) ((x) << 20)
+#define ASPEED_JTAG_CTL_LASPEED_INST BIT(17)
+#define ASPEED_JTAG_CTL_INST_EN BIT(16)
+#define ASPEED_JTAG_CTL_DR_UPDATE BIT(10)
+#define ASPEED_JTAG_CTL_DATA_LEN(x) ((x) << 4)
+#define ASPEED_JTAG_CTL_LASPEED_DATA BIT(1)
+#define ASPEED_JTAG_CTL_DATA_EN BIT(0)
+
+/* ASPEED_JTAG_ISR : Interrupt status and enable */
+#define ASPEED_JTAG_ISR_INST_PAUSE BIT(19)
+#define ASPEED_JTAG_ISR_INST_COMPLETE BIT(18)
+#define ASPEED_JTAG_ISR_DATA_PAUSE BIT(17)
+#define ASPEED_JTAG_ISR_DATA_COMPLETE BIT(16)
+#define ASPEED_JTAG_ISR_INST_PAUSE_EN BIT(3)
+#define ASPEED_JTAG_ISR_INST_COMPLETE_EN BIT(2)
+#define ASPEED_JTAG_ISR_DATA_PAUSE_EN BIT(1)
+#define ASPEED_JTAG_ISR_DATA_COMPLETE_EN BIT(0)
+#define ASPEED_JTAG_ISR_INT_EN_MASK GENMASK(3, 0)
+#define ASPEED_JTAG_ISR_INT_MASK GENMASK(19, 16)
+
+/* ASPEED_JTAG_SW : Software Mode and Status */
+#define ASPEED_JTAG_SW_MODE_EN BIT(19)
+#define ASPEED_JTAG_SW_MODE_TCK BIT(18)
+#define ASPEED_JTAG_SW_MODE_TMS BIT(17)
+#define ASPEED_JTAG_SW_MODE_TDIO BIT(16)
+
+/* ASPEED_JTAG_TCK : TCK Control */
+#define ASPEED_JTAG_TCK_DIVISOR_MASK GENMASK(10, 0)
+#define ASPEED_JTAG_TCK_GET_DIV(x) ((x) & ASPEED_JTAG_TCK_DIVISOR_MASK)
+
+/* ASPEED_JTAG_EC : Controller set for go to IDLE */
+#define ASPEED_JTAG_EC_GO_IDLE BIT(0)
+
+#define ASPEED_JTAG_IOUT_LEN(len) (ASPEED_JTAG_CTL_ENG_EN |\
+ ASPEED_JTAG_CTL_ENG_OUT_EN |\
+ ASPEED_JTAG_CTL_INST_LEN(len))
+
+#define ASPEED_JTAG_DOUT_LEN(len) (ASPEED_JTAG_CTL_ENG_EN |\
+ ASPEED_JTAG_CTL_ENG_OUT_EN |\
+ ASPEED_JTAG_CTL_DATA_LEN(len))
+
+#define ASPEED_JTAG_TCK_WAIT 10
+#define ASPEED_JTAG_RESET_CNTR 10
+
+#define ASPEED_JTAG_NAME "jtag-aspeed"
+
+struct aspeed_jtag {
+ void __iomem *reg_base;
+ struct device *dev;
+ struct clk *pclk;
+ enum jtag_endstate status;
+ int irq;
+ u32 flag;
+ wait_queue_head_t jtag_wq;
+ bool is_open;
+};
+
+static char *end_status_str[] = {"idle", "ir pause", "drpause"};
+
+static u32 aspeed_jtag_read(struct aspeed_jtag *aspeed_jtag, u32 reg)
+{
+ return readl(aspeed_jtag->reg_base + reg);
+}
+
+static void
+aspeed_jtag_write(struct aspeed_jtag *aspeed_jtag, u32 val, u32 reg)
+{
+ writel(val, aspeed_jtag->reg_base + reg);
+}
+
+static int aspeed_jtag_freq_set(struct jtag *jtag, __u32 freq)
+{
+ struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+ unsigned long apb_frq;
+ u32 tck_val;
+ u16 div;
+
+ apb_frq = clk_get_rate(aspeed_jtag->pclk);
+ div = (apb_frq % freq == 0) ? (apb_frq / freq) - 1 : (apb_frq / freq);
+ tck_val = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_TCK);
+ aspeed_jtag_write(aspeed_jtag,
+ (tck_val & ASPEED_JTAG_TCK_DIVISOR_MASK) | div,
+ ASPEED_JTAG_TCK);
+ return 0;
+}
+
+static int aspeed_jtag_freq_get(struct jtag *jtag, __u32 *frq)
+{
+ struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+ u32 pclk;
+ u32 tck;
+
+ pclk = clk_get_rate(aspeed_jtag->pclk);
+ tck = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_TCK);
+ *frq = pclk / (ASPEED_JTAG_TCK_GET_DIV(tck) + 1);
+
+ return 0;
+}
+
+static void aspeed_jtag_sw_delay(struct aspeed_jtag *aspeed_jtag, int cnt)
+{
+ int i;
+
+ for (i = 0; i < cnt; i++)
+ aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_SW);
+}
+
+static char aspeed_jtag_tck_cycle(struct aspeed_jtag *aspeed_jtag,
+ u8 tms, u8 tdi)
+{
+ char tdo = 0;
+
+ /* TCK = 0 */
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+ (tms * ASPEED_JTAG_SW_MODE_TMS) |
+ (tdi * ASPEED_JTAG_SW_MODE_TDIO), ASPEED_JTAG_SW);
+
+ aspeed_jtag_sw_delay(aspeed_jtag, ASPEED_JTAG_TCK_WAIT);
+
+ /* TCK = 1 */
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+ ASPEED_JTAG_SW_MODE_TCK |
+ (tms * ASPEED_JTAG_SW_MODE_TMS) |
+ (tdi * ASPEED_JTAG_SW_MODE_TDIO), ASPEED_JTAG_SW);
+
+ if (aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_SW) &
+ ASPEED_JTAG_SW_MODE_TDIO)
+ tdo = 1;
+
+ aspeed_jtag_sw_delay(aspeed_jtag, ASPEED_JTAG_TCK_WAIT);
+
+ /* TCK = 0 */
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+ (tms * ASPEED_JTAG_SW_MODE_TMS) |
+ (tdi * ASPEED_JTAG_SW_MODE_TDIO), ASPEED_JTAG_SW);
+ return tdo;
+}
+
+static void aspeed_jtag_wait_instruction_pause(struct aspeed_jtag *aspeed_jtag)
+{
+ wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
+ ASPEED_JTAG_ISR_INST_PAUSE);
+ aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_INST_PAUSE;
+}
+
+static void
+aspeed_jtag_wait_instruction_complete(struct aspeed_jtag *aspeed_jtag)
+{
+ wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
+ ASPEED_JTAG_ISR_INST_COMPLETE);
+ aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_INST_COMPLETE;
+}
+
+static void
+aspeed_jtag_wait_data_pause_complete(struct aspeed_jtag *aspeed_jtag)
+{
+ wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
+ ASPEED_JTAG_ISR_DATA_PAUSE);
+ aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_DATA_PAUSE;
+}
+
+static void aspeed_jtag_wait_data_complete(struct aspeed_jtag *aspeed_jtag)
+{
+ wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
+ ASPEED_JTAG_ISR_DATA_COMPLETE);
+ aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_DATA_COMPLETE;
+}
+
+static void aspeed_jtag_sm_cycle(struct aspeed_jtag *aspeed_jtag, const u8 *tms,
+ int len)
+{
+ int i;
+
+ for (i = 0; i < len; i++)
+ aspeed_jtag_tck_cycle(aspeed_jtag, tms[i], 0);
+}
+
+static void aspeed_jtag_run_test_idle_sw(struct aspeed_jtag *aspeed_jtag,
+ struct jtag_run_test_idle *runtest)
+{
+ static const char sm_pause_irpause[] = {1, 1, 1, 1, 0, 1, 0};
+ static const char sm_pause_drpause[] = {1, 1, 1, 0, 1, 0};
+ static const char sm_idle_irpause[] = {1, 1, 0, 1, 0};
+ static const char sm_idle_drpause[] = {1, 0, 1, 0};
+ static const char sm_pause_idle[] = {1, 1, 0};
+ int i;
+
+ /* SW mode from idle/pause-> to pause/idle */
+ if (runtest->reset) {
+ for (i = 0; i < ASPEED_JTAG_RESET_CNTR; i++)
+ aspeed_jtag_tck_cycle(aspeed_jtag, 1, 0);
+ }
+
+ switch (aspeed_jtag->status) {
+ case JTAG_STATE_IDLE:
+ switch (runtest->endstate) {
+ case JTAG_STATE_PAUSEIR:
+ /* ->DRSCan->IRSCan->IRCap->IRExit1->PauseIR */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_idle_irpause,
+ sizeof(sm_idle_irpause));
+
+ aspeed_jtag->status = JTAG_STATE_PAUSEIR;
+ break;
+ case JTAG_STATE_PAUSEDR:
+ /* ->DRSCan->DRCap->DRExit1->PauseDR */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_idle_drpause,
+ sizeof(sm_idle_drpause));
+
+ aspeed_jtag->status = JTAG_STATE_PAUSEDR;
+ break;
+ case JTAG_STATE_IDLE:
+ /* IDLE */
+ aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0);
+ aspeed_jtag->status = JTAG_STATE_IDLE;
+ break;
+ default:
+ break;
+ }
+ break;
+
+ case JTAG_STATE_PAUSEIR:
+ /* Fall-through */
+ case JTAG_STATE_PAUSEDR:
+ /* From IR/DR Pause */
+ switch (runtest->endstate) {
+ case JTAG_STATE_PAUSEIR:
+ /*
+ * to Exit2 IR/DR->Updt IR/DR->DRSCan->IRSCan->IRCap->
+ * IRExit1->PauseIR
+ */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_irpause,
+ sizeof(sm_pause_irpause));
+
+ aspeed_jtag->status = JTAG_STATE_PAUSEIR;
+ break;
+ case JTAG_STATE_PAUSEDR:
+ /*
+ * to Exit2 IR/DR->Updt IR/DR->DRSCan->DRCap->
+ * DRExit1->PauseDR
+ */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_drpause,
+ sizeof(sm_pause_drpause));
+ aspeed_jtag->status = JTAG_STATE_PAUSEDR;
+ break;
+ case JTAG_STATE_IDLE:
+ /* to Exit2 IR/DR->Updt IR/DR->IDLE */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_idle,
+ sizeof(sm_pause_idle));
+ aspeed_jtag->status = JTAG_STATE_IDLE;
+ break;
+ default:
+ break;
+ }
+ break;
+
+ default:
+ dev_err(aspeed_jtag->dev, "aspeed_jtag_run_test_idle error\n");
+ break;
+ }
+
+ /* Stay on IDLE for at least TCK cycle */
+ for (i = 0; i < runtest->tck; i++)
+ aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0);
+}
+
+/**
+ * aspeed_jtag_run_test_idle:
+ * JTAG reset: generates at least 9 TMS high and 1 TMS low to force
+ * devices into Run-Test/Idle State.
+ */
+static int aspeed_jtag_idle(struct jtag *jtag,
+ struct jtag_run_test_idle *runtest)
+{
+ struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+
+ dev_dbg(aspeed_jtag->dev, "aspeed_jtag runtest, status:%d, mode:%s, state:%s, reset:%d, tck:%d\n",
+ aspeed_jtag->status, runtest->mode ? "SW" : "HW",
+ end_status_str[runtest->endstate], runtest->reset,
+ runtest->tck);
+
+ if (runtest->mode) {
+ aspeed_jtag_run_test_idle_sw(aspeed_jtag, runtest);
+ return 0;
+ }
+
+ /* Disable sw mode */
+ aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_SW);
+ /* x TMS high + 1 TMS low */
+ if (runtest->reset)
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_CTL_ENG_EN |
+ ASPEED_JTAG_CTL_ENG_OUT_EN |
+ ASPEED_JTAG_CTL_FORCE_TMS, ASPEED_JTAG_CTRL);
+ else
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_EC_GO_IDLE,
+ ASPEED_JTAG_EC);
+
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+ ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
+
+ aspeed_jtag->status = JTAG_STATE_IDLE;
+ return 0;
+}
+
+static void aspeed_jtag_xfer_sw(struct aspeed_jtag *aspeed_jtag,
+ struct jtag_xfer *xfer, unsigned long *data)
+{
+ unsigned long remain_xfer = xfer->length;
+ unsigned long shift_bits = 0;
+ unsigned long index = 0;
+ unsigned long tdi;
+ char tdo;
+
+ if (xfer->direction == JTAG_READ_XFER)
+ tdi = UINT_MAX;
+ else
+ tdi = data[index];
+
+ while (remain_xfer > 1) {
+ tdo = aspeed_jtag_tck_cycle(aspeed_jtag, 0,
+ tdi & ASPEED_JTAG_DATA_MSB);
+ data[index] |= tdo << (shift_bits %
+ ASPEED_JTAG_DATA_CHUNK_SIZE);
+
+ tdi >>= 1;
+ shift_bits++;
+ remain_xfer--;
+
+ if (shift_bits % ASPEED_JTAG_DATA_CHUNK_SIZE == 0) {
+ dev_dbg(aspeed_jtag->dev, "R/W data[%lu]:%lx\n",
+ index, data[index]);
+
+ tdo = 0;
+ index++;
+
+ if (xfer->direction == JTAG_READ_XFER)
+ tdi = UINT_MAX;
+ else
+ tdi = data[index];
+ }
+ }
+
+ tdo = aspeed_jtag_tck_cycle(aspeed_jtag, 1, tdi & ASPEED_JTAG_DATA_MSB);
+ data[index] |= tdo << (shift_bits % ASPEED_JTAG_DATA_CHUNK_SIZE);
+}
+
+static void aspeed_jtag_xfer_push_data(struct aspeed_jtag *aspeed_jtag,
+ enum jtag_xfer_type type, u32 bits_len)
+{
+ dev_dbg(aspeed_jtag->dev, "shift bits %d\n", bits_len);
+
+ if (type == JTAG_SIR_XFER) {
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_IOUT_LEN(bits_len),
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_DOUT_LEN(bits_len) |
+ ASPEED_JTAG_CTL_INST_EN, ASPEED_JTAG_CTRL);
+ } else {
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_DOUT_LEN(bits_len),
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_DOUT_LEN(bits_len) |
+ ASPEED_JTAG_CTL_DATA_EN, ASPEED_JTAG_CTRL);
+ }
+}
+
+static void aspeed_jtag_xfer_push_data_last(struct aspeed_jtag *aspeed_jtag,
+ enum jtag_xfer_type type,
+ u32 shift_bits,
+ enum jtag_endstate endstate)
+{
+ if (endstate != JTAG_STATE_IDLE) {
+ if (type == JTAG_SIR_XFER) {
+ dev_dbg(aspeed_jtag->dev, "IR Keep Pause\n");
+
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_IOUT_LEN(shift_bits),
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_IOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_INST_EN,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_wait_instruction_pause(aspeed_jtag);
+ } else {
+ dev_dbg(aspeed_jtag->dev, "DR Keep Pause\n");
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_DOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_DR_UPDATE,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_DOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_DR_UPDATE |
+ ASPEED_JTAG_CTL_DATA_EN,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_wait_data_pause_complete(aspeed_jtag);
+ }
+ } else {
+ if (type == JTAG_SIR_XFER) {
+ dev_dbg(aspeed_jtag->dev, "IR go IDLE\n");
+
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_IOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_LASPEED_INST,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_IOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_LASPEED_INST |
+ ASPEED_JTAG_CTL_INST_EN,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_wait_instruction_complete(aspeed_jtag);
+ } else {
+ dev_dbg(aspeed_jtag->dev, "DR go IDLE\n");
+
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_DOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_LASPEED_DATA,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_DOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_LASPEED_DATA |
+ ASPEED_JTAG_CTL_DATA_EN,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_wait_data_complete(aspeed_jtag);
+ }
+ }
+}
+
+static void aspeed_jtag_xfer_hw(struct aspeed_jtag *aspeed_jtag,
+ struct jtag_xfer *xfer, unsigned long *data)
+{
+ unsigned long remain_xfer = xfer->length;
+ unsigned long index = 0;
+ char shift_bits;
+ u32 data_reg;
+
+ data_reg = xfer->type == JTAG_SIR_XFER ?
+ ASPEED_JTAG_INST : ASPEED_JTAG_DATA;
+ while (remain_xfer) {
+ if (xfer->direction == JTAG_WRITE_XFER) {
+ dev_dbg(aspeed_jtag->dev, "W dr->dr_data[%lu]:%lx\n",
+ index, data[index]);
+
+ aspeed_jtag_write(aspeed_jtag, data[index], data_reg);
+ } else {
+ aspeed_jtag_write(aspeed_jtag, 0, data_reg);
+ }
+
+ if (remain_xfer > ASPEED_JTAG_DATA_CHUNK_SIZE) {
+ shift_bits = ASPEED_JTAG_DATA_CHUNK_SIZE;
+
+ /*
+ * Read bytes were not equals to column length
+ * and go to Pause-DR
+ */
+ aspeed_jtag_xfer_push_data(aspeed_jtag, xfer->type,
+ shift_bits);
+ } else {
+ /*
+ * Read bytes equals to column length =>
+ * Update-DR
+ */
+ shift_bits = remain_xfer;
+ aspeed_jtag_xfer_push_data_last(aspeed_jtag, xfer->type,
+ shift_bits,
+ xfer->endstate);
+ }
+
+ if (xfer->direction == JTAG_READ_XFER) {
+ if (shift_bits < ASPEED_JTAG_DATA_CHUNK_SIZE) {
+ data[index] = aspeed_jtag_read(aspeed_jtag,
+ data_reg);
+
+ data[index] >>= ASPEED_JTAG_DATA_CHUNK_SIZE -
+ shift_bits;
+ } else {
+ data[index] = aspeed_jtag_read(aspeed_jtag,
+ data_reg);
+ }
+ dev_dbg(aspeed_jtag->dev, "R dr->dr_data[%lu]:%lx\n",
+ index, data[index]);
+ }
+
+ remain_xfer = remain_xfer - shift_bits;
+ index++;
+ dev_dbg(aspeed_jtag->dev, "remain_xfer %lu\n", remain_xfer);
+ }
+}
+
+static int aspeed_jtag_xfer(struct jtag *jtag, struct jtag_xfer *xfer)
+{
+ static const char sm_update_shiftir[] = {1, 1, 0, 0};
+ static const char sm_update_shiftdr[] = {1, 0, 0};
+ static const char sm_pause_idle[] = {1, 1, 0};
+ static const char sm_pause_update[] = {1, 1};
+ unsigned long *data = jtag_u64_to_ptr(xfer->tdio);
+ struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+ unsigned long remain_xfer = xfer->length;
+ unsigned long offset;
+ char dbg_str[256];
+ int pos = 0;
+ int i;
+
+ for (offset = 0, i = 0; offset < xfer->length;
+ offset += ASPEED_JTAG_DATA_CHUNK_SIZE, i++) {
+ pos += snprintf(&dbg_str[pos], sizeof(dbg_str) - pos,
+ "0x%08lx ", data[i]);
+ }
+
+ dev_dbg(aspeed_jtag->dev, "aspeed_jtag %s %s xfer, mode:%s, END:%d, len:%lu, TDI[%s]\n",
+ xfer->type == JTAG_SIR_XFER ? "SIR" : "SDR",
+ xfer->direction == JTAG_READ_XFER ? "READ" : "WRITE",
+ xfer->mode ? "SW" : "HW",
+ xfer->endstate, remain_xfer, dbg_str);
+
+ if (xfer->mode == JTAG_XFER_SW_MODE) {
+ /* SW mode */
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+ ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
+
+ if (aspeed_jtag->status != JTAG_STATE_IDLE) {
+ /*IR/DR Pause->Exit2 IR / DR->Update IR /DR */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_update,
+ sizeof(sm_pause_update));
+ }
+
+ if (xfer->type == JTAG_SIR_XFER)
+ /* ->IRSCan->CapIR->ShiftIR */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_update_shiftir,
+ sizeof(sm_update_shiftir));
+ else
+ /* ->DRScan->DRCap->DRShift */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_update_shiftdr,
+ sizeof(sm_update_shiftdr));
+
+ aspeed_jtag_xfer_sw(aspeed_jtag, xfer, data);
+
+ /* DIPause/DRPause */
+ aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0);
+
+ if (xfer->endstate == JTAG_STATE_IDLE) {
+ /* ->DRExit2->DRUpdate->IDLE */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_idle,
+ sizeof(sm_pause_idle));
+ }
+ } else {
+ /* hw mode */
+ aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_SW);
+ aspeed_jtag_xfer_hw(aspeed_jtag, xfer, data);
+ }
+
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+ ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
+ aspeed_jtag->status = xfer->endstate;
+ return 0;
+}
+
+static int aspeed_jtag_status_get(struct jtag *jtag, __u32 *status)
+{
+ struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+
+ *status = aspeed_jtag->status;
+ return 0;
+}
+
+static irqreturn_t aspeed_jtag_interrupt(s32 this_irq, void *dev_id)
+{
+ struct aspeed_jtag *aspeed_jtag = dev_id;
+ irqreturn_t ret;
+ u32 status;
+
+ status = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_ISR);
+ dev_dbg(aspeed_jtag->dev, "status %x\n", status);
+
+ if (status & ASPEED_JTAG_ISR_INT_MASK) {
+ aspeed_jtag_write(aspeed_jtag,
+ (status & ASPEED_JTAG_ISR_INT_MASK)
+ | (status & ASPEED_JTAG_ISR_INT_EN_MASK),
+ ASPEED_JTAG_ISR);
+ aspeed_jtag->flag |= status & ASPEED_JTAG_ISR_INT_MASK;
+ }
+
+ if (aspeed_jtag->flag) {
+ wake_up_interruptible(&aspeed_jtag->jtag_wq);
+ ret = IRQ_HANDLED;
+ } else {
+ dev_err(aspeed_jtag->dev, "aspeed_jtag irq status:%x\n",
+ status);
+ ret = IRQ_NONE;
+ }
+ return ret;
+}
+
+int aspeed_jtag_init(struct platform_device *pdev,
+ struct aspeed_jtag *aspeed_jtag)
+{
+ struct resource *res;
+ int err;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ aspeed_jtag->reg_base = devm_ioremap_resource(aspeed_jtag->dev, res);
+ if (IS_ERR(aspeed_jtag->reg_base)) {
+ err = -ENOMEM;
+ goto out_region;
+ }
+
+ aspeed_jtag->pclk = devm_clk_get(aspeed_jtag->dev, NULL);
+ if (IS_ERR(aspeed_jtag->pclk)) {
+ dev_err(aspeed_jtag->dev, "devm_clk_get failed\n");
+ return PTR_ERR(aspeed_jtag->pclk);
+ }
+
+ clk_prepare_enable(aspeed_jtag->pclk);
+
+ aspeed_jtag->irq = platform_get_irq(pdev, 0);
+ if (aspeed_jtag->irq < 0) {
+ dev_err(aspeed_jtag->dev, "no irq specified\n");
+ err = -ENOENT;
+ goto out_region;
+ }
+
+ /* Enable clock */
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_CTL_ENG_EN |
+ ASPEED_JTAG_CTL_ENG_OUT_EN, ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+ ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
+
+ err = devm_request_irq(aspeed_jtag->dev, aspeed_jtag->irq,
+ aspeed_jtag_interrupt, 0,
+ "aspeed-jtag", aspeed_jtag);
+ if (err) {
+ dev_err(aspeed_jtag->dev, "aspeed_jtag unable to get IRQ");
+ goto out_region;
+ }
+ dev_dbg(&pdev->dev, "aspeed_jtag:IRQ %d.\n", aspeed_jtag->irq);
+
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_ISR_INST_PAUSE |
+ ASPEED_JTAG_ISR_INST_COMPLETE |
+ ASPEED_JTAG_ISR_DATA_PAUSE |
+ ASPEED_JTAG_ISR_DATA_COMPLETE |
+ ASPEED_JTAG_ISR_INST_PAUSE_EN |
+ ASPEED_JTAG_ISR_INST_COMPLETE_EN |
+ ASPEED_JTAG_ISR_DATA_PAUSE_EN |
+ ASPEED_JTAG_ISR_DATA_COMPLETE_EN,
+ ASPEED_JTAG_ISR);
+
+ aspeed_jtag->flag = 0;
+ init_waitqueue_head(&aspeed_jtag->jtag_wq);
+ return 0;
+
+out_region:
+ release_mem_region(res->start, resource_size(res));
+ return err;
+}
+
+int aspeed_jtag_deinit(struct platform_device *pdev,
+ struct aspeed_jtag *aspeed_jtag)
+{
+ aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_ISR);
+ devm_free_irq(aspeed_jtag->dev, aspeed_jtag->irq, aspeed_jtag);
+ /* Disabe clock */
+ aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_CTRL);
+ clk_disable_unprepare(aspeed_jtag->pclk);
+ return 0;
+}
+
+static const struct jtag_ops aspeed_jtag_ops = {
+ .freq_get = aspeed_jtag_freq_get,
+ .freq_set = aspeed_jtag_freq_set,
+ .status_get = aspeed_jtag_status_get,
+ .idle = aspeed_jtag_idle,
+ .xfer = aspeed_jtag_xfer
+};
+
+static int aspeed_jtag_probe(struct platform_device *pdev)
+{
+ struct aspeed_jtag *aspeed_jtag;
+ struct jtag *jtag;
+ int err;
+
+ if (!of_device_is_compatible(pdev->dev.of_node, "aspeed,aspeed-jtag"))
+ return -ENOMEM;
+
+ jtag = jtag_alloc(sizeof(*aspeed_jtag), &aspeed_jtag_ops);
+ if (!jtag)
+ return -ENODEV;
+
+ platform_set_drvdata(pdev, jtag);
+ aspeed_jtag = jtag_priv(jtag);
+ aspeed_jtag->dev = &pdev->dev;
+
+ /* Initialize device*/
+ err = aspeed_jtag_init(pdev, aspeed_jtag);
+ if (err)
+ goto err_jtag_init;
+
+ /* Initialize JTAG core structure*/
+ err = jtag_register(jtag);
+ if (err)
+ goto err_jtag_register;
+
+ return 0;
+
+err_jtag_register:
+ aspeed_jtag_deinit(pdev, aspeed_jtag);
+err_jtag_init:
+ jtag_free(jtag);
+ return err;
+}
+
+static int aspeed_jtag_remove(struct platform_device *pdev)
+{
+ struct jtag *jtag;
+
+ jtag = platform_get_drvdata(pdev);
+ aspeed_jtag_deinit(pdev, jtag_priv(jtag));
+ jtag_unregister(jtag);
+ jtag_free(jtag);
+ return 0;
+}
+
+static const struct of_device_id aspeed_jtag_of_match[] = {
+ { .compatible = "aspeed,aspeed2400-jtag", },
+ { .compatible = "aspeed,aspeed2500-jtag", },
+ {}
+};
+
+static struct platform_driver aspeed_jtag_driver = {
+ .probe = aspeed_jtag_probe,
+ .remove = aspeed_jtag_remove,
+ .driver = {
+ .name = ASPEED_JTAG_NAME,
+ .of_match_table = aspeed_jtag_of_match,
+ },
+};
+module_platform_driver(aspeed_jtag_driver);
+
+MODULE_AUTHOR("Oleksandr Shamray <oleksandrs@mellanox.com>");
+MODULE_DESCRIPTION("ASPEED JTAG driver");
+MODULE_LICENSE("GPL v2");
--
1.7.1
^ permalink raw reply related
* [patch v7 1/4] drivers: jtag: Add JTAG core driver
From: Oleksandr Shamray @ 2017-09-01 16:06 UTC (permalink / raw)
To: gregkh, arnd
Cc: linux-kernel, linux-arm-kernel, devicetree, openbmc, joel, jiri,
tklauser, linux-serial, mec, vadimp, system-sw-low-level, robh+dt,
openocd-devel-owner, linux-api, davem, mchehab, Oleksandr Shamray,
Jiri Pirko
In-Reply-To: <1504281966-6199-1-git-send-email-oleksandrs@mellanox.com>
Initial patch for JTAG friver
JTAG class driver provide infrastructure to support hardware/software
JTAG platform drivers. It provide user layer API interface for flashing
and debugging external devices which equipped with JTAG interface
using standard transactions.
Driver exposes set of IOCTL to user space for:
- XFER:
- SIR (Scan Instruction Register, IEEE 1149.1 Data Register scan);
- SDR (Scan Data Register, IEEE 1149.1 Instruction Register scan);
- RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
number of clocks).
- SIOCFREQ/GIOCFREQ for setting and reading JTAG frequency.
Driver core provides set of internal APIs for allocation and
registration:
- jtag_register;
- jtag_unregister;
- jtag_alloc;
- jtag_free;
Platform driver on registration with jtag-core creates the next
entry in dev folder:
/dev/jtagX
Signed-off-by: Oleksandr Shamray <oleksandrs@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
---
v6->v7
Notifications from kbuild test robot <lkp@intel.com>
- Remove include asm/types.h from jtag.h
- Add include <linux/types.h> to jtag.c
v5->v6
v4->v5
v3->v4
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- change transaction pointer tdio type to __u64
- change internal status type from enum to __u32
- reorder jtag_xfer members to aviod the implied padding
- add __packed attribute to jtag_xfer and jtag_run_test_idle
v2->v3
Notifications from kbuild test robot <lkp@intel.com>
- Change include path to <linux/types.h> in jtag.h
v1->v2
Comments pointed by Greg KH <gregkh@linuxfoundation.org>
- Change license type from GPLv2/BSD to GPLv2
- Change type of variables which crossed user/kernel to __type
- Remove "default n" from Kconfig
Comments pointed by Andrew Lunn <andrew@lunn.ch>
- Change list_add_tail in jtag_unregister to list_del
Comments pointed by Neil Armstrong <narmstrong@baylibre.com>
- Add SPDX-License-Identifier instead of license text
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- Change __copy_to_user to memdup_user
- Change __put_user to put_user
- Change type of variables to __type for compatible 32 and 64-bit systems
- Add check for maximum xfer data size
- Change lookup data mechanism to get jtag data from inode
- Add .compat_ioctl to file ops
- Add mem alignment for jtag priv data
Comments pointed by Tobias Klauser <tklauser@distanz.ch>
- Change function names to avoid match with variable types
- Fix description for jtag_ru_test_idle in uapi jtag.h
- Fix misprints IDEL/IDLE, trough/through
---
Documentation/ioctl/ioctl-number.txt | 2 +
MAINTAINERS | 8 +
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/jtag/Kconfig | 16 ++
drivers/jtag/Makefile | 1 +
drivers/jtag/jtag.c | 312 ++++++++++++++++++++++++++++++++++
include/linux/jtag.h | 48 +++++
include/uapi/linux/jtag.h | 111 ++++++++++++
9 files changed, 501 insertions(+), 0 deletions(-)
create mode 100644 drivers/jtag/Kconfig
create mode 100644 drivers/jtag/Makefile
create mode 100644 drivers/jtag/jtag.c
create mode 100644 include/linux/jtag.h
create mode 100644 include/uapi/linux/jtag.h
diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index 3e3fdae..1af2508 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -321,6 +321,8 @@ Code Seq#(hex) Include File Comments
0xB0 all RATIO devices in development:
<mailto:vgo@ratio.de>
0xB1 00-1F PPPoX <mailto:mostrows@styx.uwaterloo.ca>
+0xB2 00-0f linux/jtag.h JTAG driver
+ <mailto:oleksandrs@mellanox.com>
0xB3 00 linux/mmc/ioctl.h
0xB4 00-0F linux/gpio.h <mailto:linux-gpio@vger.kernel.org>
0xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@vger.kernel.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 205d397..141aeaf 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7292,6 +7292,14 @@ L: linux-serial@vger.kernel.org
S: Maintained
F: drivers/tty/serial/jsm/
+JTAG SUBSYSTEM
+M: Oleksandr Shamray <oleksandrs@mellanox.com>
+M: Vadim Pasternak <vadimp@mellanox.com>
+S: Maintained
+F: include/linux/jtag.h
+F: include/uapi/linux/jtag.h
+F: drivers/jtag/
+
K10TEMP HARDWARE MONITORING DRIVER
M: Clemens Ladisch <clemens@ladisch.de>
L: linux-hwmon@vger.kernel.org
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 505c676..2214678 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -208,4 +208,6 @@ source "drivers/tee/Kconfig"
source "drivers/mux/Kconfig"
+source "drivers/jtag/Kconfig"
+
endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index dfdcda0..6a2059b 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -182,3 +182,4 @@ obj-$(CONFIG_FPGA) += fpga/
obj-$(CONFIG_FSI) += fsi/
obj-$(CONFIG_TEE) += tee/
obj-$(CONFIG_MULTIPLEXER) += mux/
+obj-$(CONFIG_JTAG) += jtag/
diff --git a/drivers/jtag/Kconfig b/drivers/jtag/Kconfig
new file mode 100644
index 0000000..0fad1a3
--- /dev/null
+++ b/drivers/jtag/Kconfig
@@ -0,0 +1,16 @@
+menuconfig JTAG
+ tristate "JTAG support"
+ ---help---
+ This provides basic core functionality support for jtag class devices
+ Hardware equipped with JTAG microcontroller which can be built
+ on top of this drivers. Driver exposes the set of IOCTL to the
+ user space for:
+ SIR (Scan Instruction Register, IEEE 1149.1 Data Register scan);
+ SDR (Scan Data Register, IEEE 1149.1 Instruction Register scan);
+ RUNTEST (Forces IEEE 1149.1 bus to a run state for specified
+ number of clocks).
+
+ If you want this support, you should say Y here.
+
+ To compile this driver as a module, choose M here: the module will
+ be called jtag.
diff --git a/drivers/jtag/Makefile b/drivers/jtag/Makefile
new file mode 100644
index 0000000..af37493
--- /dev/null
+++ b/drivers/jtag/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_JTAG) += jtag.o
diff --git a/drivers/jtag/jtag.c b/drivers/jtag/jtag.c
new file mode 100644
index 0000000..f948d4c
--- /dev/null
+++ b/drivers/jtag/jtag.c
@@ -0,0 +1,312 @@
+/*
+ * drivers/jtag/jtag.c
+ *
+ * Copyright (c) 2017 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2017 Oleksandr Shamray <oleksandrs@mellanox.com>
+ *
+ * Released under the GPLv2 only.
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/jtag.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/rtnetlink.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <uapi/linux/jtag.h>
+
+struct jtag {
+ struct list_head list;
+ struct device *dev;
+ struct cdev cdev;
+ int id;
+ spinlock_t lock;
+ int open;
+ const struct jtag_ops *ops;
+ unsigned long priv[0] __aligned(ARCH_DMA_MINALIGN);
+};
+
+static dev_t jtag_devt;
+static LIST_HEAD(jtag_list);
+static DEFINE_MUTEX(jtag_mutex);
+static DEFINE_IDA(jtag_ida);
+
+void *jtag_priv(struct jtag *jtag)
+{
+ return jtag->priv;
+}
+EXPORT_SYMBOL_GPL(jtag_priv);
+
+static __u64 jtag_copy_from_user(__u64 udata, unsigned long bit_size)
+{
+ unsigned long size;
+ void *kdata;
+
+ size = DIV_ROUND_UP(bit_size, BITS_PER_BYTE);
+ kdata = memdup_user(u64_to_user_ptr(udata), size);
+
+ return (__u64)(uintptr_t)kdata;
+}
+
+static unsigned long jtag_copy_to_user(__u64 udata, __u64 kdata,
+ unsigned long bit_size)
+{
+ unsigned long size;
+
+ size = DIV_ROUND_UP(bit_size, BITS_PER_BYTE);
+
+ return copy_to_user(u64_to_user_ptr(udata), jtag_u64_to_ptr(kdata),
+ size);
+}
+
+static struct class jtag_class = {
+ .name = "jtag",
+ .owner = THIS_MODULE,
+};
+
+static int jtag_run_test_idle_op(struct jtag *jtag,
+ struct jtag_run_test_idle *idle)
+{
+ if (jtag->ops->idle)
+ return jtag->ops->idle(jtag, idle);
+ else
+ return -EOPNOTSUPP;
+}
+
+static int jtag_xfer_op(struct jtag *jtag, struct jtag_xfer *xfer)
+{
+ if (jtag->ops->xfer)
+ return jtag->ops->xfer(jtag, xfer);
+ else
+ return -EOPNOTSUPP;
+}
+
+static long jtag_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct jtag *jtag = file->private_data;
+ __u32 *uarg = (__u32 __user *)arg;
+ void *varg = (void __user *)arg;
+ struct jtag_run_test_idle idle;
+ struct jtag_xfer xfer;
+ __u64 tdio_user;
+ __u32 value;
+ int err;
+
+ switch (cmd) {
+ case JTAG_GIOCFREQ:
+ if (jtag->ops->freq_get)
+ err = jtag->ops->freq_get(jtag, &value);
+ else
+ err = -EOPNOTSUPP;
+ if (err)
+ break;
+
+ err = put_user(value, uarg);
+ break;
+
+ case JTAG_SIOCFREQ:
+ err = __get_user(value, uarg);
+
+ if (value == 0)
+ err = -EINVAL;
+ if (err)
+ break;
+
+ if (jtag->ops->freq_set)
+ err = jtag->ops->freq_set(jtag, value);
+ else
+ err = -EOPNOTSUPP;
+ break;
+
+ case JTAG_IOCRUNTEST:
+ if (copy_from_user(&idle, varg,
+ sizeof(struct jtag_run_test_idle)))
+ return -ENOMEM;
+ err = jtag_run_test_idle_op(jtag, &idle);
+ break;
+
+ case JTAG_IOCXFER:
+ if (copy_from_user(&xfer, varg, sizeof(struct jtag_xfer)))
+ return -EFAULT;
+
+ if (xfer.length >= JTAG_MAX_XFER_DATA_LEN)
+ return -EFAULT;
+
+ tdio_user = xfer.tdio;
+ xfer.tdio = jtag_copy_from_user(xfer.tdio, xfer.length);
+ if (!xfer.tdio)
+ return -ENOMEM;
+
+ err = jtag_xfer_op(jtag, &xfer);
+ if (jtag_copy_to_user(tdio_user, xfer.tdio, xfer.length)) {
+ kfree(jtag_u64_to_ptr(xfer.tdio));
+ return -EFAULT;
+ }
+
+ kfree(jtag_u64_to_ptr(xfer.tdio));
+ xfer.tdio = tdio_user;
+ if (copy_to_user(varg, &xfer, sizeof(struct jtag_xfer)))
+ return -EFAULT;
+ break;
+
+ case JTAG_GIOCSTATUS:
+ if (jtag->ops->status_get)
+ err = jtag->ops->status_get(jtag, &value);
+ else
+ err = -EOPNOTSUPP;
+ if (err)
+ break;
+
+ err = put_user(value, uarg);
+ break;
+
+ default:
+ return -EINVAL;
+ }
+ return err;
+}
+
+#ifdef CONFIG_COMPAT
+static long jtag_ioctl_compat(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ return jtag_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static int jtag_open(struct inode *inode, struct file *file)
+{
+ struct jtag *jtag = container_of(inode->i_cdev, struct jtag, cdev);
+
+ spin_lock(&jtag->lock);
+
+ if (jtag->open) {
+ dev_info(NULL, "jtag already opened\n");
+ spin_unlock(&jtag->lock);
+ return -EBUSY;
+ }
+
+ jtag->open++;
+ file->private_data = jtag;
+ spin_unlock(&jtag->lock);
+ return 0;
+}
+
+static int jtag_release(struct inode *inode, struct file *file)
+{
+ struct jtag *jtag = file->private_data;
+
+ spin_lock(&jtag->lock);
+ jtag->open--;
+ spin_unlock(&jtag->lock);
+ return 0;
+}
+
+static const struct file_operations jtag_fops = {
+ .owner = THIS_MODULE,
+ .open = jtag_open,
+ .release = jtag_release,
+ .llseek = noop_llseek,
+ .unlocked_ioctl = jtag_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = jtag_ioctl_compat,
+#endif
+};
+
+struct jtag *jtag_alloc(size_t priv_size, const struct jtag_ops *ops)
+{
+ struct jtag *jtag;
+
+ jtag = kzalloc(sizeof(*jtag) + round_up(priv_size, ARCH_DMA_MINALIGN),
+ GFP_KERNEL);
+ if (!jtag)
+ return NULL;
+
+ jtag->ops = ops;
+ return jtag;
+}
+EXPORT_SYMBOL_GPL(jtag_alloc);
+
+void jtag_free(struct jtag *jtag)
+{
+ kfree(jtag);
+}
+EXPORT_SYMBOL_GPL(jtag_free);
+
+int jtag_register(struct jtag *jtag)
+{
+ int id;
+ int err;
+
+ id = ida_simple_get(&jtag_ida, 0, 0, GFP_KERNEL);
+ if (id < 0)
+ return id;
+
+ jtag->id = id;
+ cdev_init(&jtag->cdev, &jtag_fops);
+ jtag->cdev.owner = THIS_MODULE;
+ err = cdev_add(&jtag->cdev, MKDEV(MAJOR(jtag_devt), jtag->id), 1);
+ if (err)
+ goto err_cdev;
+
+ /* Register this jtag device with the driver core */
+ jtag->dev = device_create(&jtag_class, NULL, MKDEV(MAJOR(jtag_devt),
+ jtag->id),
+ NULL, "jtag%d", jtag->id);
+ if (!jtag->dev)
+ goto err_device_create;
+
+ jtag->open = 0;
+ dev_set_drvdata(jtag->dev, jtag);
+ spin_lock_init(&jtag->lock);
+ mutex_lock(&jtag_mutex);
+ list_add_tail(&jtag->list, &jtag_list);
+ mutex_unlock(&jtag_mutex);
+ return err;
+
+err_device_create:
+ cdev_del(&jtag->cdev);
+err_cdev:
+ ida_simple_remove(&jtag_ida, id);
+ return err;
+}
+EXPORT_SYMBOL_GPL(jtag_register);
+
+void jtag_unregister(struct jtag *jtag)
+{
+ struct device *dev = jtag->dev;
+
+ mutex_lock(&jtag_mutex);
+ list_del(&jtag->list);
+ mutex_unlock(&jtag_mutex);
+ cdev_del(&jtag->cdev);
+ device_unregister(dev);
+ ida_simple_remove(&jtag_ida, jtag->id);
+}
+EXPORT_SYMBOL_GPL(jtag_unregister);
+
+static int __init jtag_init(void)
+{
+ int err;
+
+ err = alloc_chrdev_region(&jtag_devt, 0, 1, "jtag");
+ if (err)
+ return err;
+ return class_register(&jtag_class);
+}
+
+static void __exit jtag_exit(void)
+{
+ class_unregister(&jtag_class);
+}
+
+module_init(jtag_init);
+module_exit(jtag_exit);
+
+MODULE_AUTHOR("Oleksandr Shamray <oleksandrs@mellanox.com>");
+MODULE_DESCRIPTION("Generic jtag support");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/jtag.h b/include/linux/jtag.h
new file mode 100644
index 0000000..f48ae9d
--- /dev/null
+++ b/include/linux/jtag.h
@@ -0,0 +1,48 @@
+/*
+ * drivers/jtag/jtag.c
+ *
+ * Copyright (c) 2017 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2017 Oleksandr Shamray <oleksandrs@mellanox.com>
+ *
+ * Released under the GPLv2 only.
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#ifndef __JTAG_H
+#define __JTAG_H
+
+#include <uapi/linux/jtag.h>
+
+#ifndef ARCH_DMA_MINALIGN
+#define ARCH_DMA_MINALIGN 1
+#endif
+
+#define jtag_u64_to_ptr(arg) ((void *)(uintptr_t)arg)
+
+#define JTAG_MAX_XFER_DATA_LEN 65535
+
+struct jtag;
+/**
+ * struct jtag_ops - callbacks for jtag control functions:
+ *
+ * @freq_get: get frequency function. Filled by device driver
+ * @freq_set: set frequency function. Filled by device driver
+ * @status_get: set status function. Filled by device driver
+ * @idle: set JTAG to idle state function. Filled by device driver
+ * @xfer: send JTAG xfer function. Filled by device driver
+ */
+struct jtag_ops {
+ int (*freq_get)(struct jtag *jtag, __u32 *freq);
+ int (*freq_set)(struct jtag *jtag, __u32 freq);
+ int (*status_get)(struct jtag *jtag, __u32 *state);
+ int (*idle)(struct jtag *jtag, struct jtag_run_test_idle *idle);
+ int (*xfer)(struct jtag *jtag, struct jtag_xfer *xfer);
+};
+
+void *jtag_priv(struct jtag *jtag);
+int jtag_register(struct jtag *jtag);
+void jtag_unregister(struct jtag *jtag);
+struct jtag *jtag_alloc(size_t priv_size, const struct jtag_ops *ops);
+void jtag_free(struct jtag *jtag);
+
+#endif /* __JTAG_H */
diff --git a/include/uapi/linux/jtag.h b/include/uapi/linux/jtag.h
new file mode 100644
index 0000000..af22ea6
--- /dev/null
+++ b/include/uapi/linux/jtag.h
@@ -0,0 +1,111 @@
+/*
+ * JTAG class driver
+ *
+ * Copyright (c) 2017 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2017 Oleksandr Shamray <oleksandrs@mellanox.com>
+ *
+ * Released under the GPLv2/BSD.
+ * SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+ */
+
+#ifndef __UAPI_LINUX_JTAG_H
+#define __UAPI_LINUX_JTAG_H
+
+/**
+ * enum jtag_xfer_mode:
+ *
+ * @JTAG_XFER_HW_MODE: hardware mode transfer
+ * @JTAG_XFER_SW_MODE: software mode transfer
+ */
+enum jtag_xfer_mode {
+ JTAG_XFER_HW_MODE,
+ JTAG_XFER_SW_MODE,
+};
+
+/**
+ * enum jtag_endstate:
+ *
+ * @JTAG_STATE_IDLE: JTAG state machine IDLE state
+ * @JTAG_STATE_PAUSEIR: JTAG state machine PAUSE_IR state
+ * @JTAG_STATE_PAUSEDR: JTAG state machine PAUSE_DR state
+ */
+enum jtag_endstate {
+ JTAG_STATE_IDLE,
+ JTAG_STATE_PAUSEIR,
+ JTAG_STATE_PAUSEDR,
+};
+
+/**
+ * enum jtag_xfer_type:
+ *
+ * @JTAG_SIR_XFER: SIR transfer
+ * @JTAG_SDR_XFER: SDR transfer
+ */
+enum jtag_xfer_type {
+ JTAG_SIR_XFER,
+ JTAG_SDR_XFER,
+};
+
+/**
+ * enum jtag_xfer_direction:
+ *
+ * @JTAG_READ_XFER: read transfer
+ * @JTAG_WRITE_XFER: write transfer
+ */
+enum jtag_xfer_direction {
+ JTAG_READ_XFER,
+ JTAG_WRITE_XFER,
+};
+
+/**
+ * struct jtag_run_test_idle - forces JTAG state machine to
+ * RUN_TEST/IDLE state
+ *
+ * @mode: access mode
+ * @reset: 0 - run IDLE/PAUSE from current state
+ * 1 - go through TEST_LOGIC/RESET state before IDLE/PAUSE
+ * @end: completion flag
+ * @tck: clock counter
+ *
+ * Structure represents interface to JTAG device for jtag idle
+ * execution.
+ */
+struct jtag_run_test_idle {
+ __u8 mode;
+ __u8 reset;
+ __u8 endstate;
+ __u8 tck;
+};
+
+/**
+ * struct jtag_xfer - jtag xfer:
+ *
+ * @mode: access mode
+ * @type: transfer type
+ * @direction: xfer direction
+ * @length: xfer bits len
+ * @tdio : xfer data array
+ * @endir: xfer end state
+ *
+ * Structure represents interface to Aspeed JTAG device for jtag sdr xfer
+ * execution.
+ */
+struct jtag_xfer {
+ __u8 mode;
+ __u8 type;
+ __u8 direction;
+ __u8 endstate;
+ __u32 length;
+ __u64 tdio;
+};
+
+#define __JTAG_IOCTL_MAGIC 0xb2
+
+#define JTAG_IOCRUNTEST _IOW(__JTAG_IOCTL_MAGIC, 0,\
+ struct jtag_run_test_idle)
+#define JTAG_SIOCFREQ _IOW(__JTAG_IOCTL_MAGIC, 1, unsigned int)
+#define JTAG_GIOCFREQ _IOR(__JTAG_IOCTL_MAGIC, 2, unsigned int)
+#define JTAG_IOCXFER _IOWR(__JTAG_IOCTL_MAGIC, 3, struct jtag_xfer)
+#define JTAG_GIOCSTATUS _IOWR(__JTAG_IOCTL_MAGIC, 4, enum jtag_endstate)
+
+#endif /* __UAPI_LINUX_JTAG_H */
--
1.7.1
^ permalink raw reply related
* [patch v7 0/4] JTAG driver introduction
From: Oleksandr Shamray @ 2017-09-01 16:06 UTC (permalink / raw)
To: gregkh, arnd
Cc: linux-kernel, linux-arm-kernel, devicetree, openbmc, joel, jiri,
tklauser, linux-serial, mec, vadimp, system-sw-low-level, robh+dt,
openocd-devel-owner, linux-api, davem, mchehab, Oleksandr Shamray
When a need raise up to use JTAG interface for system's devices
programming or CPU debugging, usually the user layer
application implements jtag protocol by bit-bang or using a
proprietary connection to vendor hardware.
This method can be slow and not generic.
We propose to implement general JTAG interface and infrastructure
to communicate with user layer application. In such way, we can
have the standard JTAG interface core part and separation from
specific HW implementation.
This allow new capability to debug the CPU or program system's
device via BMC without additional devices nor cost.
This patch purpose is to add JTAG master core infrastructure by
defining new JTAG class and provide generic JTAG interface
to allow hardware specific drivers to connect this interface.
This will enable all JTAG drivers to use the common interface
part and will have separate for hardware implementation.
The JTAG (Joint Test Action Group) core driver provides minimal generic
JTAG interface, which can be used by hardware specific JTAG master
controllers. By providing common interface for the JTAG controllers,
user space device programing is hardware independent.
Modern SoC which in use for embedded system' equipped with
internal JTAG master interface.
This interface is used for programming and debugging system's
hardware components, like CPLD, FPGA, CPU, voltage and
industrial controllers.
Firmware for such devices can be upgraded through JTAG interface during
Runtime. The JTAG standard support for multiple devices programming,
is in case their lines are daisy-chained together.
For example, systems which equipped with host CPU, BMC SoC or/and
number of programmable devices are capable to connect a pin and
select system components dynamically for programming and debugging,
This is using by the BMC which is equipped with internal SoC master
controller.
For example:
BMC JTAG master --> pin selected to CPLDs chain for programming (filed
upgrade, production)
BMC JTAG master --> pin selected to voltage monitors for programming
(field upgrade, production)
BMC JTAG master --> pin selected to host CPU (on-site debugging
and developers debugging)
For example, we can have application in user space which using calls
to JTAG driver executes CPLD programming directly from SVF file
The JTAG standard (IEEE 1149.1) defines the next connector pins:
- TDI (Test Data In);
- TDO (Test Data Out);
- TCK (Test Clock);
- TMS (Test Mode Select);
- TRST (Test Reset) (Optional);
The SoC equipped with JTAG master controller, performs
device programming on command or vector level. For example
a file in a standard SVF (Serial Vector Format) that contains
boundary scan vectors, can be used by sending each vector
to the JTAG interface and the JTAG controller will execute
the programming.
Initial version provides the system calls set for:
- SIR (Scan Instruction Register, IEEE 1149.1 Data Register scan);
- SDR (Scan Data Register, IEEE 1149.1 Instruction Register scan);
- RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
number of clocks.
SoC which are not equipped with JTAG master interface, can be built
on top of JTAG core driver infrastructure, by applying bit-banging of
TDI, TDO, TCK and TMS pins within the hardware specific driver.
Oleksandr Shamray (4):
drivers: jtag: Add JTAG core driver
drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master
driver
Documentation: jtag: Add bindings for Aspeed SoC 24xx and 25xx
families JTAG master driver
Documentation: jtag: Add ABI documentation
Documentation/ABI/testing/jatg-cdev | 27 +
.../devicetree/bindings/jtag/aspeed-jtag.txt | 18 +
Documentation/ioctl/ioctl-number.txt | 2 +
MAINTAINERS | 10 +
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/jtag/Kconfig | 29 +
drivers/jtag/Makefile | 2 +
drivers/jtag/jtag-aspeed.c | 773 ++++++++++++++++++++
drivers/jtag/jtag.c | 312 ++++++++
include/linux/jtag.h | 48 ++
include/uapi/linux/jtag.h | 111 +++
12 files changed, 1335 insertions(+), 0 deletions(-)
create mode 100644 Documentation/ABI/testing/jatg-cdev
create mode 100644 Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
create mode 100644 drivers/jtag/Kconfig
create mode 100644 drivers/jtag/Makefile
create mode 100644 drivers/jtag/jtag-aspeed.c
create mode 100644 drivers/jtag/jtag.c
create mode 100644 include/linux/jtag.h
create mode 100644 include/uapi/linux/jtag.h
^ permalink raw reply
* Re: [PATCH v3] earlycon: initialise baud field of earlycon device structure
From: Eugeniy Paltsev @ 2017-08-31 13:33 UTC (permalink / raw)
To: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, jslaby@suse.com,
gregkh@linuxfoundation.org, linux-snps-arc@lists.infradead.org
In-Reply-To: <20170821162213.27102-1-Eugeniy.Paltsev@synopsys.com>
Hi,
Maybe you have any comments or remarks about this patch?
And if you don't could you please apply it.
Thanks.
On Mon, 2017-08-21 at 19:22 +0300, Eugeniy Paltsev wrote:
> For now baud field of earlycon structure device is't initialised at all
> in of_setup_earlycon (in oppositе to register_earlycon).
>
> So when I use stdout-path to point earlycon device
> (like stdout-path = &serial or stdout-path = "serial:115200n8")
> baud field of earlycon device structure remains uninitialised and
> earlycon initialization is not performed correctly as
> of_setup_earlycon is used.
> When pass all arguments via bootargs
> (like bootargs = "earlycon=uart8250,mmio32,0xf0005000,115200n8")
> initialization is performed correctly as register_earlycon is used.
>
> So initialise baud field of earlycon device structure by value of
> "current-speed" property from device tree or from options
> (if they exist) when we use of_setup_earlycon
>
> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
> ---
> Changes v2 -> v3:
> * Use simple_strtoul instead of kstrtoul as with kstrtoul we can't parse
> options string which includes arguments except baudrate (like "115200n8")
>
> Changes v1 -> v2:
> * Use standart property name "current-speed" instead of custom "baud"
>
> NOTE:
> I don't add parsing of the other standard options here because we don't
> have any place to store them. When we parce and set options of the 'real'
> uart device (using uart_parse_options + uart_set_options) we populate
> ktermios structure an pass it to port->ops->set_termios callback of
> uart_port structure. So it is processing by uart driver itself. But we don't
> register such callbacks for earlycon. So we are only able to parse baud
> value, which can be stored in baud field of earlycon_device structure.
>
> drivers/tty/serial/earlycon.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
> index c365154..82e813b 100644
> --- a/drivers/tty/serial/earlycon.c
> +++ b/drivers/tty/serial/earlycon.c
> @@ -282,7 +282,12 @@ int __init of_setup_earlycon(const struct earlycon_id *match,
> }
> }
>
> + val = of_get_flat_dt_prop(node, "current-speed", NULL);
> + if (val)
> + early_console_dev.baud = be32_to_cpu(*val);
> +
> if (options) {
> + early_console_dev.baud = simple_strtoul(options, NULL, 0);
> strlcpy(early_console_dev.options, options,
> sizeof(early_console_dev.options));
> }
--
Eugeniy Paltsev
^ permalink raw reply
* Re: [PATCH] tty: xilinx_uartps: move to arch_initcall for earlier console
From: Linus Walleij @ 2017-08-31 12:59 UTC (permalink / raw)
To: Michal Simek
Cc: Greg KH, Shubhrajyoti Datta, linux-serial@vger.kernel.org,
linux-kernel@vger.kernel.org, shubhrajyoti.datta
In-Reply-To: <62daa70c-0c6f-7628-efa4-308cfe93709c@xilinx.com>
On Thu, Aug 24, 2017 at 11:32 AM, Michal Simek <michal.simek@xilinx.com> wrote:
> On 24.8.2017 01:24, Greg KH wrote:
>> On Wed, Aug 23, 2017 at 04:50:21PM +0530, Shubhrajyoti Datta wrote:
>>> Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
>>
>> I can't take patches without any changelog text at all :(
>
> ok. I see you have also commented this.
>
> Anyway this is kind of old discussion about moving serial drivers to
> arch_initcall from module_init.
>
> There is one patch in the tree.
>
> commit 4dd9e742df98f8f600b4302d3adbb087a68237f7
> Author: Alessandro Rubini <rubini@gnudd.com>
> AuthorDate: Tue May 5 05:54:13 2009 +0100
> Commit: Russell King <rmk+kernel@arm.linux.org.uk>
> CommitDate: Sun May 31 14:58:11 2009 +0100
>
> [ARM] 5505/1: serial amba-pl011: move to arch_initcall for earlier
> console
>
> Signed-off-by: Alessandro Rubini <rubini@unipv.it>"
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
>
>
> and then there was one patch (also sent to linux-serial but don't have link)
> https://patches.linaro.org/patch/14633/
>
> where that discussion wasn't finished.
Yeah Alessandro never came back on that.
I *guess* it is to get the console up really early, simply becaus it is
quite helpful for spotting early boot problems.
It is not for earlydebug, because for that we use another routine
that hammers out the characters on the console. That is what we use
before even going to console, with printascii(), I usually use a patch
like this:
--- a/init/main.c
+++ b/init/main.c
@@ -515,6 +515,12 @@ asmlinkage __visible void __init start_kernel(void)
smp_setup_processor_id();
debug_objects_early_init();
+#ifdef CONFIG_ARM
+ {
+ extern void printascii(char *);
+ printascii("start_kernel\n");
+ }
+#endif
/*
* Set up the initial canary ASAP:
*/
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index fc47863f629c..85edd1401406 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1726,6 +1726,13 @@ asmlinkage int vprintk_emit(int facility, int level,
lflags |= LOG_NEWLINE;
}
+#ifdef CONFIG_ARM
+ {
+ extern void printascii(char *);
+ printascii(textbuf);
+ }
+#endif
+
/* strip kernel syslog prefix and extract log level or control flags */
if (facility == 0) {
int kern_level;
Yours,
Linus Walleij
^ permalink raw reply related
* Re: [PATCH][serial-next] serial: 8250: don't dereference em485 until it has been null checked
From: Andy Shevchenko @ 2017-08-29 20:22 UTC (permalink / raw)
To: Dan Carpenter, Colin King
Cc: Greg Kroah-Hartman, Jiri Slaby, Phil Elwell, Jan Kiszka,
Eric Anholt, Thor Thayer, Rafael Gago, David Lechner,
linux-serial, kernel-janitors, linux-kernel
In-Reply-To: <20170829200411.wbqdsihcnhpg2gmr@mwanda>
On Tue, 2017-08-29 at 23:04 +0300, Dan Carpenter wrote:
> On Tue, Aug 29, 2017 at 05:58:15PM +0100, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> >
> > Currently, the pointer em485 is dereferenced to get p and then later
> > em485 is checked to see if it is null before calling __start_tx. In
> > the case where em485 is null, we get a null pointer dereference. Fix
> > this by moving the deference and the associated spinlock/unlocks on
> > p to the code block where em485 is known to be not null.
> >
> > Detected by CoverityScan, CID#14555001 ("Dereference before null
> > check")
> >
> > Fixes 6e0a5de2136b ("serial: 8250: Use hrtimers for rs485 delays")
>
> I don't understand which tree this commit is from. I have it fetched
> but when I do a git log on drivers/tty/serial/8250/8250_port.c then I
> don't see it. I have today's linux-next.
I see it, though I have tty-next as well.
> I'm pretty sure "t" isn't ever NULL.
(I'm pretty sure there is a false positive, though code would be cleaned
to avoid such reports)
--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
^ permalink raw reply
* Re: [PATCH][serial-next] serial: 8250: don't dereference em485 until it has been null checked
From: Dan Carpenter @ 2017-08-29 20:04 UTC (permalink / raw)
To: Colin King
Cc: Greg Kroah-Hartman, Jiri Slaby, Andy Shevchenko, Phil Elwell,
Jan Kiszka, Eric Anholt, Thor Thayer, Rafael Gago, David Lechner,
linux-serial, kernel-janitors, linux-kernel
In-Reply-To: <20170829165815.23429-1-colin.king@canonical.com>
On Tue, Aug 29, 2017 at 05:58:15PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> Currently, the pointer em485 is dereferenced to get p and then later
> em485 is checked to see if it is null before calling __start_tx. In
> the case where em485 is null, we get a null pointer dereference. Fix
> this by moving the deference and the associated spinlock/unlocks on
> p to the code block where em485 is known to be not null.
>
> Detected by CoverityScan, CID#14555001 ("Dereference before null check")
>
> Fixes 6e0a5de2136b ("serial: 8250: Use hrtimers for rs485 delays")
I don't understand which tree this commit is from. I have it fetched
but when I do a git log on drivers/tty/serial/8250/8250_port.c then I
don't see it. I have today's linux-next.
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> drivers/tty/serial/8250/8250_port.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
> index 4726aa276968..c20b581313f0 100644
> --- a/drivers/tty/serial/8250/8250_port.c
> +++ b/drivers/tty/serial/8250/8250_port.c
> @@ -1606,18 +1606,18 @@ static inline void start_tx_rs485(struct uart_port *port)
> static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t)
I'm pretty sure "t" isn't ever NULL.
regards,
dan carpenter
^ permalink raw reply
* Re: [PATCH][serial-next] serial: 8250: don't dereference em485 until it has been null checked
From: Andy Shevchenko @ 2017-08-29 19:57 UTC (permalink / raw)
To: Colin King, Greg Kroah-Hartman, Jiri Slaby, Phil Elwell,
Jan Kiszka, Eric Anholt, Thor Thayer, Rafael Gago, David Lechner,
linux-serial
Cc: kernel-janitors, linux-kernel
In-Reply-To: <20170829165815.23429-1-colin.king@canonical.com>
On Tue, 2017-08-29 at 17:58 +0100, Colin King wrote:
> Currently, the pointer em485 is dereferenced to get p and then later
> em485 is checked to see if it is null before calling __start_tx. In
> the case where em485 is null, we get a null pointer dereference. Fix
> this by moving the deference and the associated spinlock/unlocks on
> p to the code block where em485 is known to be not null.
> static enum hrtimer_restart serial8250_em485_handle_start_tx(struct
> hrtimer *t)
> {
> struct uart_8250_em485 *em485;
> - struct uart_8250_port *p;
> unsigned long flags;
> em485 = container_of(t, struct uart_8250_em485,
> start_tx_timer);
> - p = em485->port;
>
> - spin_lock_irqsave(&p->port.lock, flags);
> if (em485 &&
> em485->active_timer == &em485->start_tx_timer) {
> + struct uart_8250_port *p = em485->port;
> +
> + spin_lock_irqsave(&p->port.lock, flags);
Can you describe, please, what on your opinion is protected by this
lock?
> __start_tx(&p->port);
> em485->active_timer = NULL;
> + spin_unlock_irqrestore(&p->port.lock, flags);
> }
> - spin_unlock_irqrestore(&p->port.lock, flags);
> return HRTIMER_NORESTART;
> }
>
--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
^ permalink raw reply
* [PATCH][serial-next] serial: 8250: don't dereference em485 until it has been null checked
From: Colin King @ 2017-08-29 16:58 UTC (permalink / raw)
To: Greg Kroah-Hartman, Jiri Slaby, Andy Shevchenko, Phil Elwell,
Jan Kiszka, Eric Anholt, Thor Thayer, Rafael Gago, David Lechner,
linux-serial
Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
Currently, the pointer em485 is dereferenced to get p and then later
em485 is checked to see if it is null before calling __start_tx. In
the case where em485 is null, we get a null pointer dereference. Fix
this by moving the deference and the associated spinlock/unlocks on
p to the code block where em485 is known to be not null.
Detected by CoverityScan, CID#14555001 ("Dereference before null check")
Fixes 6e0a5de2136b ("serial: 8250: Use hrtimers for rs485 delays")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/tty/serial/8250/8250_port.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 4726aa276968..c20b581313f0 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1606,18 +1606,18 @@ static inline void start_tx_rs485(struct uart_port *port)
static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t)
{
struct uart_8250_em485 *em485;
- struct uart_8250_port *p;
unsigned long flags;
em485 = container_of(t, struct uart_8250_em485, start_tx_timer);
- p = em485->port;
- spin_lock_irqsave(&p->port.lock, flags);
if (em485 &&
em485->active_timer == &em485->start_tx_timer) {
+ struct uart_8250_port *p = em485->port;
+
+ spin_lock_irqsave(&p->port.lock, flags);
__start_tx(&p->port);
em485->active_timer = NULL;
+ spin_unlock_irqrestore(&p->port.lock, flags);
}
- spin_unlock_irqrestore(&p->port.lock, flags);
return HRTIMER_NORESTART;
}
--
2.14.1
^ permalink raw reply related
* Re: [patch v1 0/2] JTAG driver introduction
From: Pavel Machek @ 2017-08-28 20:03 UTC (permalink / raw)
To: Andrew Lunn
Cc: Oleksandr Shamray,
gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org,
arnd-r2nGTMty4D4@public.gmane.org,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
jiri-rHqAuBHg3fBzbRFIqnYvSA@public.gmane.org, system-sw-low-level,
openbmc-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
mec-WqBc5aa1uDFeoWH0uzbU5w@public.gmane.org,
joel-U3u1mxZcP9KHXe+LvDLADg@public.gmane.org,
linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
vadimp-45czdsxZ+A5DPfheJLI6IQ@public.gmane.org,
tklauser-93Khv+1bN0NyDzI6CaY1VQ@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
In-Reply-To: <20170803174822.GI15018-g2DYL2Zd6BY@public.gmane.org>
[-- Attachment #1: Type: text/plain, Size: 1106 bytes --]
Hi!
> > Thanks a lot for review.
> >
>
> > We used user space tool for that, which is an adaptation of some
> > Lattice tools, which allows programming of SVF files. We are using
> > it for Lattice CPLD burning, since we have for such devices on our
> > system, but this tool could be used for programming other devices
> > from other vendors as well.
>
> > https://github.com/mellanoxbmc/mellanox-bmc-tools
>
> Since you are defining a new Kernel ABI here, it would be good to get
> some buy-in from potential users for the ABI. Maybe for the next
> version of the patchset you can cross post to the OpenOCD-devel list?
Actually, since you are defining a new ABI, it would be nice to have a
Documentation/ file with the ABI description, so that people can
review it...
Otherwise... yes, this looks like a step in right direction from 60000
feet above. I guess it is still a lot of work to get gdb running...
Thanks,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]
^ permalink raw reply
* Re: [PATCH 0/6] serdev multiplexing support
From: Greg KH @ 2017-08-28 12:55 UTC (permalink / raw)
To: Ulrich Hecht
Cc: linux-serial, linux-renesas-soc, magnus.damm, laurent.pinchart,
wsa, robh, peda, geert, linux-i2c
In-Reply-To: <1502889748-31499-1-git-send-email-ulrich.hecht+renesas@gmail.com>
On Wed, Aug 16, 2017 at 03:22:22PM +0200, Ulrich Hecht wrote:
> Hi!
>
> Here's a new version of serdev multiplexing support. Thanks to everybody who
> commented; I think I have included all non-optional suggestions. :)
> Changes are manifold, please refer to the changelog below.
>
> This version drops "mux: include compiler.h from mux/consumer.h",
> which is on its way upstream by now.
>
> CU
> Uli
Rob, any thoughts on this series?
thanks,
greg k-h
^ permalink raw reply
* Re: [PATCH 3/8] tty/bcm63xx_uart: use refclk for the expected clock name
From: Greg Kroah-Hartman @ 2017-08-28 12:51 UTC (permalink / raw)
To: Jonas Gorski
Cc: linux-mips-6z/3iImG2C8G8FEW9MqTrA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
linux-serial-u79uwXL29TY76Z2rM5mHXA,
devicetree-u79uwXL29TY76Z2rM5mHXA, netdev-u79uwXL29TY76Z2rM5mHXA,
Rob Herring, Mark Rutland, Ralf Baechle, Florian Fainelli,
bcm-kernel-feedback-list-dY08KVG/lbpWk0Htik3J/w, Kevin Cernekee,
Jiri Slaby, David S. Miller, Russell King
In-Reply-To: <20170802093429.12572-4-jonas.gorski-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
On Wed, Aug 02, 2017 at 11:34:24AM +0200, Jonas Gorski wrote:
> We now have the clock available under refclk, so use that.
>
> Signed-off-by: Jonas Gorski <jonas.gorski-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Acked-by: Greg Kroah-Hartman <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
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^ permalink raw reply
* Re: [PATCH] USB: serial: ti_usb_3410_5052: Port uart_mode from io_ti.
From: Greg KH @ 2017-08-28 8:56 UTC (permalink / raw)
To: Stuart Longland
Cc: linux-serial-u79uwXL29TY76Z2rM5mHXA,
alborchers-2TsfIrYsZRL7O9PZeWXHPg,
linux-usb-u79uwXL29TY76Z2rM5mHXA
In-Reply-To: <20170818025659.4402-1-stuartl-EoQOJlg3kTYQrrorzV6ljw@public.gmane.org>
On Fri, Aug 18, 2017 at 12:56:59PM +1000, Stuart Longland wrote:
> This introduces the `uart_mode` sysfs attribute as seen in the `io_ti`
> USB serial driver, allowing this USB serial interface to be switched
> between RS-232, 2-wire RS-485 and 4-wire RS-485.
>
> /sys/class/tty/ttyUSB${num}/device/uart takes a single integer:
>
> 0: RS-232 mode (default for RS-232-compatible dongles)
> 1: RS-485 2w mode (default for RS-485-only dongles)
> 2: RS-485 4w mode / RS-422 mode
>
> Write this *before* opening your serial device.
Please don't create random driver-specific sysfs files for something as
generic as this type of userspace api.
Also, you didn't create a Documentation/ABI/ file describing this, so
even if I wanted to take it, I couldn't :)
Anyway, work on a "real" solution for this for all serial devices
please.
thanks,
greg k-h
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^ permalink raw reply
* Re: [patch v6 3/3] Doccumentation: jtag: Add bindings for Aspeed SoC 24xx and 25xx families JTAG master driver
From: Tobias Klauser @ 2017-08-28 8:36 UTC (permalink / raw)
To: Oleksandr Shamray
Cc: gregkh, arnd, linux-kernel, linux-arm-kernel, devicetree, openbmc,
joel, jiri, linux-serial, mec, vadimp, system-sw-low-level,
robh+dt, openocd-devel-owner, linux-api, Jiri Pirko
In-Reply-To: <1503418256-5215-4-git-send-email-oleksandrs@mellanox.com>
On 2017-08-22 at 18:10:56 +0200, Oleksandr Shamray <oleksandrs@mellanox.com> wrote:
> It has been tested on Mellanox system with BMC equipped with
> Aspeed 2520 SoC for programming CPLD devices.
>
> Signed-off-by: Oleksandr Shamray <oleksandrs@mellanox.com>
> Signed-off-by: Jiri Pirko <jiri@mellanox.com>
> Acked-by: Rob Herring <robh@kernel.org>
> ---
> v5->v6
> Comments pointed by Tobias Klauser <tklauser@distanz.ch>
> - Small nit: s/doccumentation/Documentation/
There's still one 'c' too many in 'Doccumentation' in the subject (in
case you're doing another respin of the series).
^ permalink raw reply
* Re: [PATCH v2 RESEND 1/2] dt-bindings: serial: 8250: Add MediaTek BTIF controller bindings
From: Matthias Brugger @ 2017-08-28 5:21 UTC (permalink / raw)
To: Sean Wang
Cc: robh+dt-DgEjT+Ai2ygdnm+yROfE0A,
gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r, jslaby-IBi9RG/b67k,
andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA,
robert.jarzmik-GANU6spQydw, arnd-r2nGTMty4D4,
p.zabel-bIcnvbaLZ9MEGnE8C9+IrQ, joel-U3u1mxZcP9KHXe+LvDLADg,
david-nq/r/kbU++upp/zk7JDF2g, jan.kiszka-kv7WeFo6aLtBDgjK7y7TUQ,
heikki.krogerus-VuQAYsv1563Yd54FQh9/CA,
hpeter-Re5JQEeQqe8AvxtiuMwx3w, vigneshr-l0cyMroinI0,
tthayer-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx,
devicetree-u79uwXL29TY76Z2rM5mHXA,
linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
linux-serial-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
linux-kernel-u79uwXL29TY76Z2rM5mHXA
In-Reply-To: <1503862785.19230.76.camel@mtkswgap22>
On 08/27/2017 10:39 PM, Sean Wang wrote:
> On Sun, 2017-08-27 at 22:00 +0300, Matthias Brugger wrote:
>>
>> On 08/19/2017 09:06 PM, sean.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org wrote:
>>> From: Sean Wang <sean.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
>>>
>>> Document the devicetree bindings in 8250.txt for MediaTek BTIF
>>> controller which could be found on MT7622 and MT7623 SoC.
>>>
>>> Signed-off-by: Sean Wang <sean.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
>>> ---
>>> Documentation/devicetree/bindings/serial/8250.txt | 3 +++
>>> 1 file changed, 3 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/serial/8250.txt b/Documentation/devicetree/bindings/serial/8250.txt
>>> index 419ff6c..7528d90 100644
>>> --- a/Documentation/devicetree/bindings/serial/8250.txt
>>> +++ b/Documentation/devicetree/bindings/serial/8250.txt
>>> @@ -14,6 +14,9 @@ Required properties:
>>> tegra132, or tegra210.
>>> - "nxp,lpc3220-uart"
>>> - "ralink,rt2880-uart"
>>> + - For MediaTek MT7623, must contain "mediatek,mt7623-btif"
>>> + - For other MediaTek SoCs , must contain "mediatek,<chip>-btif",
>>> + "mediatek,mt7623-btif" where <chip> is mt7622.
>>
>> Hm, to me that's confusing. What about:
>> "mediatek,mt7623-btif": for MediaTek MT7623
>> "mediatek,mt7622-btif", "mediatek,mt7623-btif": for MediaTek MT7622
>>
>> If in the future we have more SoCs that support the BTIF, we should add them
>> like the mt7622 case.
>>
>
> I had v3, but it should have similar logic and also got ack from Rob
>
> I knew all your logic of adding binding document for all MediaTek
> devices, even I alway added MediaTek device in dt-bindings as the way
> you mentioned here, but I felt this way is fine for this kind of
> dedicated document.
>
> The reason i don't add it as usual is the following. 8250.txt is common
> and shared among all uart like devices, so i don't want btif device
> occupies too much section and bloat the document when every new MediaTek
> SoC is introduced.
>
> So instead I refer to existing Nvidia device added in 8250.txt which I
> thought its way is simple, elegant and also using pattern I can use to
> add btif devices.
>
Working on my email backlog after vactions I didn't see that this was accepted
by Rob. Sorry for the noise.
Matthias
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^ permalink raw reply
* Re: [patch v6 0/3] JTAG driver introduction
From: Rick Altherr @ 2017-08-28 2:55 UTC (permalink / raw)
To: Linus Walleij
Cc: Oleksandr Shamray,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Jiří Pírko, Arnd Bergmann,
system-sw-low-level-VPRAkNaXOzVWk0Htik3J/w, Greg KH,
OpenBMC Maillist,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
openocd-devel-owner-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f,
mec-WqBc5aa1uDFeoWH0uzbU5w, Rob Herring,
linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
vadimp-45czdsxZ+A5DPfheJLI6IQ, Tobias Klauser,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
In-Reply-To: <CACRpkdb75L5BrYN+V-BMwzrRm8_Wtymr3d08eMWt43FiBpH5Qg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On Sun, Aug 27, 2017 at 3:30 PM, Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
> On Fri, Aug 25, 2017 at 6:52 PM, Rick Altherr <raltherr-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> wrote:
>
>>> Incidentally, people are sending patches to expose the FTDI
>>> expanders as common GPIO chips under Linux, so we can
>>> internally in the kernel or from the usersapce character device
>>> access them as "some GPIOs".
>>
>> I know my team at Google has an internal patch for exactly that. FTDI
>> expanders are complicated as they can be used as UART, GPIO, I2C, SPI
>> depending on configuration. Our project was using a mix of I2C and
>> GPIO so I directly my team to approach it as an MFD. I'd like to see
>> all of these use cases handled by the kernel but I understand the
>> other viewpoint of relying on libusb for cross-platform compatiblity.
>
> Hm. I see. But I see people pushing the in-kernel method so I think
> it will eventually win out.
>
SGTM. I'll see if my team can clean up the MFD-based FTDI driver and
submit it upstream.
>>>>> In my worst nightmare they export GPIO lines using
>>>>> the horrid ABI in /sys/gpio/*
>>>>
>>>> https://sourceforge.net/p/openocd/code/ci/v0.10.0/tree/src/jtag/drivers/sysfsgpio.c
>>>
>>> Gnah!
>>> Whoever writes a slot-in replacement making the character device
>>> take precendence wins lots of karma.
>>
>> If they show up at Linux Plumbers or visit San Jose, I'll take them to
>> dinner. I didn't see any docs for the chardev in Documentation. I
>> _think_ I understand how it works from reading the relevant sections
>> of gpiolib.c but I can see how users end up using sysfs instead.
>
> I intended tools/gpio/* to be the documentation:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/gpio
>
> If we need more written documentation we can do it I guess,
I haven't been in the habit of looking in tools/. Guess I should be.
>
> Yours,
> Linus Walleij
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^ permalink raw reply
* Re: [patch v6 0/3] JTAG driver introduction
From: Linus Walleij @ 2017-08-27 22:30 UTC (permalink / raw)
To: Rick Altherr
Cc: Oleksandr Shamray,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Jiří Pírko, Arnd Bergmann,
system-sw-low-level-VPRAkNaXOzVWk0Htik3J/w, Greg KH,
OpenBMC Maillist,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
openocd-devel-owner-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f,
mec-WqBc5aa1uDFeoWH0uzbU5w, Rob Herring,
linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
vadimp-45czdsxZ+A5DPfheJLI6IQ, Tobias Klauser,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
In-Reply-To: <CAPLgG=mv1p98e4Vzso1N-VU=1MSotkTmnF+DcDTXPcd3q-n8HA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On Fri, Aug 25, 2017 at 6:52 PM, Rick Altherr <raltherr-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> wrote:
>> Incidentally, people are sending patches to expose the FTDI
>> expanders as common GPIO chips under Linux, so we can
>> internally in the kernel or from the usersapce character device
>> access them as "some GPIOs".
>
> I know my team at Google has an internal patch for exactly that. FTDI
> expanders are complicated as they can be used as UART, GPIO, I2C, SPI
> depending on configuration. Our project was using a mix of I2C and
> GPIO so I directly my team to approach it as an MFD. I'd like to see
> all of these use cases handled by the kernel but I understand the
> other viewpoint of relying on libusb for cross-platform compatiblity.
Hm. I see. But I see people pushing the in-kernel method so I think
it will eventually win out.
>>>> In my worst nightmare they export GPIO lines using
>>>> the horrid ABI in /sys/gpio/*
>>>
>>> https://sourceforge.net/p/openocd/code/ci/v0.10.0/tree/src/jtag/drivers/sysfsgpio.c
>>
>> Gnah!
>> Whoever writes a slot-in replacement making the character device
>> take precendence wins lots of karma.
>
> If they show up at Linux Plumbers or visit San Jose, I'll take them to
> dinner. I didn't see any docs for the chardev in Documentation. I
> _think_ I understand how it works from reading the relevant sections
> of gpiolib.c but I can see how users end up using sysfs instead.
I intended tools/gpio/* to be the documentation:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/gpio
If we need more written documentation we can do it I guess,
Yours,
Linus Walleij
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^ permalink raw reply
* Re: [patch v6 0/3] JTAG driver introduction
From: Linus Walleij @ 2017-08-27 22:25 UTC (permalink / raw)
To: Stuart Longland
Cc: Rick Altherr, Oleksandr Shamray,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Jiří Pírko, Arnd Bergmann,
system-sw-low-level-VPRAkNaXOzVWk0Htik3J/w, Greg KH,
OpenBMC Maillist,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
openocd-devel-owner-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f,
mec-WqBc5aa1uDFeoWH0uzbU5w, Rob Herring,
linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Tobias Klauser, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
In-Reply-To: <593cd0d3-8e06-0992-c155-1322014c0477-3e+Fe6x+DsgJbe36r25VNhCuuivNXqWP@public.gmane.org>
On Fri, Aug 25, 2017 at 10:50 AM, Stuart Longland
<stuartl-3e+Fe6x+DsgJbe36r25VNhCuuivNXqWP@public.gmane.org> wrote:
> [Note: dropping vadimp-45czdsxZ+A5DPfheJLI6IQ@public.gmane.org as SMTP server complained about the
> DNS server returning NXDOMAIN. Apologies.]
> On 25/08/17 18:32, Linus Walleij wrote:
>> Gnah!
>> Whoever writes a slot-in replacement making the character device
>> take precendence wins lots of karma.
>
> What would such a replacement look like though?
Something that looks for /dev/gpiochipN and if it exists open the GPIOs
from there and make that take precedence over any /sys/gpio/*
poking.
> Some sort of system whereby you can read/write single-line commands as
> if talking to a GPIO expander over a UART?
I don't really understand the question. All GPIO expanders become
a gpiochip, and have their own character device in /dev.
> Would you access the GPIOs one by one, or would you perhaps map them
> into a bitmap (maybe arbitrarily, up to 64-bits wide) and perform masked
> operations on the bitmap?
The character device supports up to 64bits of simultaneous line
switches, but the in-kernel API can only handle 32bits
in a single register write.
> I'm no fan of the sysfs GPIO interface, but it beats poking around at
> registers behind the kernel's back.
Have a look at libgpiod and tools/gpio/* in the kernel.
Yours,
Linus Walleij
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^ permalink raw reply
* Re: [PATCH v2 RESEND 1/2] dt-bindings: serial: 8250: Add MediaTek BTIF controller bindings
From: Sean Wang @ 2017-08-27 19:39 UTC (permalink / raw)
To: Matthias Brugger
Cc: robh+dt, gregkh, jslaby, andriy.shevchenko, robert.jarzmik, arnd,
p.zabel, joel, david, jan.kiszka, heikki.krogerus, hpeter,
vigneshr, tthayer, devicetree, linux-mediatek, linux-serial,
linux-arm-kernel, linux-kernel
In-Reply-To: <8548a72a-4bf3-d44a-6d26-d64721cffe85@gmail.com>
On Sun, 2017-08-27 at 22:00 +0300, Matthias Brugger wrote:
>
> On 08/19/2017 09:06 PM, sean.wang@mediatek.com wrote:
> > From: Sean Wang <sean.wang@mediatek.com>
> >
> > Document the devicetree bindings in 8250.txt for MediaTek BTIF
> > controller which could be found on MT7622 and MT7623 SoC.
> >
> > Signed-off-by: Sean Wang <sean.wang@mediatek.com>
> > ---
> > Documentation/devicetree/bindings/serial/8250.txt | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/serial/8250.txt b/Documentation/devicetree/bindings/serial/8250.txt
> > index 419ff6c..7528d90 100644
> > --- a/Documentation/devicetree/bindings/serial/8250.txt
> > +++ b/Documentation/devicetree/bindings/serial/8250.txt
> > @@ -14,6 +14,9 @@ Required properties:
> > tegra132, or tegra210.
> > - "nxp,lpc3220-uart"
> > - "ralink,rt2880-uart"
> > + - For MediaTek MT7623, must contain "mediatek,mt7623-btif"
> > + - For other MediaTek SoCs , must contain "mediatek,<chip>-btif",
> > + "mediatek,mt7623-btif" where <chip> is mt7622.
>
> Hm, to me that's confusing. What about:
> "mediatek,mt7623-btif": for MediaTek MT7623
> "mediatek,mt7622-btif", "mediatek,mt7623-btif": for MediaTek MT7622
>
> If in the future we have more SoCs that support the BTIF, we should add them
> like the mt7622 case.
>
I had v3, but it should have similar logic and also got ack from Rob
I knew all your logic of adding binding document for all MediaTek
devices, even I alway added MediaTek device in dt-bindings as the way
you mentioned here, but I felt this way is fine for this kind of
dedicated document.
The reason i don't add it as usual is the following. 8250.txt is common
and shared among all uart like devices, so i don't want btif device
occupies too much section and bloat the document when every new MediaTek
SoC is introduced.
So instead I refer to existing Nvidia device added in 8250.txt which I
thought its way is simple, elegant and also using pattern I can use to
add btif devices.
Sean
> Make sense?
>
> Regards,
> Matthias
^ permalink raw reply
* Re: [PATCH v2 RESEND 1/2] dt-bindings: serial: 8250: Add MediaTek BTIF controller bindings
From: Matthias Brugger @ 2017-08-27 19:00 UTC (permalink / raw)
To: sean.wang-NuS5LvNUpcJWk0Htik3J/w, robh+dt-DgEjT+Ai2ygdnm+yROfE0A,
gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r, jslaby-IBi9RG/b67k,
andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA,
robert.jarzmik-GANU6spQydw, arnd-r2nGTMty4D4,
p.zabel-bIcnvbaLZ9MEGnE8C9+IrQ, joel-U3u1mxZcP9KHXe+LvDLADg,
david-nq/r/kbU++upp/zk7JDF2g, jan.kiszka-kv7WeFo6aLtBDgjK7y7TUQ,
heikki.krogerus-VuQAYsv1563Yd54FQh9/CA,
hpeter-Re5JQEeQqe8AvxtiuMwx3w, vigneshr-l0cyMroinI0,
tthayer-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA,
linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
linux-serial-u79uwXL29TY76Z2rM5mHXA,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
linux-kernel-u79uwXL29TY76Z2rM5mHXA
In-Reply-To: <29b52a3b95982f1097766d515aae09c57e11b002.1503165144.git.sean.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
On 08/19/2017 09:06 PM, sean.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org wrote:
> From: Sean Wang <sean.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
>
> Document the devicetree bindings in 8250.txt for MediaTek BTIF
> controller which could be found on MT7622 and MT7623 SoC.
>
> Signed-off-by: Sean Wang <sean.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
> ---
> Documentation/devicetree/bindings/serial/8250.txt | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/serial/8250.txt b/Documentation/devicetree/bindings/serial/8250.txt
> index 419ff6c..7528d90 100644
> --- a/Documentation/devicetree/bindings/serial/8250.txt
> +++ b/Documentation/devicetree/bindings/serial/8250.txt
> @@ -14,6 +14,9 @@ Required properties:
> tegra132, or tegra210.
> - "nxp,lpc3220-uart"
> - "ralink,rt2880-uart"
> + - For MediaTek MT7623, must contain "mediatek,mt7623-btif"
> + - For other MediaTek SoCs , must contain "mediatek,<chip>-btif",
> + "mediatek,mt7623-btif" where <chip> is mt7622.
Hm, to me that's confusing. What about:
"mediatek,mt7623-btif": for MediaTek MT7623
"mediatek,mt7622-btif", "mediatek,mt7623-btif": for MediaTek MT7622
If in the future we have more SoCs that support the BTIF, we should add them
like the mt7622 case.
Make sense?
Regards,
Matthias
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^ permalink raw reply
* Re: [PATCH] tty: serial: 8250_mtk: Use PTR_ERR_OR_ZERO
From: Matthias Brugger @ 2017-08-27 18:49 UTC (permalink / raw)
To: Himanshu Jha, gregkh; +Cc: jslaby, linux-serial, linux-arm-kernel, linux-kernel
In-Reply-To: <1503815501-9205-1-git-send-email-himanshujha199640@gmail.com>
On 08/27/2017 09:31 AM, Himanshu Jha wrote:
> Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR
>
> Signed-off-by: Himanshu Jha <himanshujha199640@gmail.com>
> ---
> drivers/tty/serial/8250/8250_mtk.c | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
> index ce0cc47..fb45770 100644
> --- a/drivers/tty/serial/8250/8250_mtk.c
> +++ b/drivers/tty/serial/8250/8250_mtk.c
> @@ -171,10 +171,7 @@ static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p,
> }
>
> data->bus_clk = devm_clk_get(&pdev->dev, "bus");
> - if (IS_ERR(data->bus_clk))
> - return PTR_ERR(data->bus_clk);
> -
> - return 0;
> + return PTR_ERR_OR_ZERO(data->bus_clk);
> }
>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
^ permalink raw reply
* [PATCH] tty: serial: 8250_mtk: Use PTR_ERR_OR_ZERO
From: Himanshu Jha @ 2017-08-27 6:31 UTC (permalink / raw)
To: gregkh
Cc: jslaby, matthias.bgg, linux-serial, linux-arm-kernel,
linux-kernel, Himanshu Jha
Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR
Signed-off-by: Himanshu Jha <himanshujha199640@gmail.com>
---
drivers/tty/serial/8250/8250_mtk.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index ce0cc47..fb45770 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -171,10 +171,7 @@ static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p,
}
data->bus_clk = devm_clk_get(&pdev->dev, "bus");
- if (IS_ERR(data->bus_clk))
- return PTR_ERR(data->bus_clk);
-
- return 0;
+ return PTR_ERR_OR_ZERO(data->bus_clk);
}
static int mtk8250_probe(struct platform_device *pdev)
--
2.7.4
^ permalink raw reply related
* Re: [patch v6 0/3] JTAG driver introduction
From: Rick Altherr @ 2017-08-25 16:53 UTC (permalink / raw)
To: Stuart Longland
Cc: Linus Walleij, Oleksandr Shamray,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Jiří Pírko, Arnd Bergmann,
system-sw-low-level-VPRAkNaXOzVWk0Htik3J/w, Greg KH,
OpenBMC Maillist,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
openocd-devel-owner-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f,
mec-WqBc5aa1uDFeoWH0uzbU5w, Rob Herring,
linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Tobias Klauser, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
In-Reply-To: <593cd0d3-8e06-0992-c155-1322014c0477-3e+Fe6x+DsgJbe36r25VNhCuuivNXqWP@public.gmane.org>
On Fri, Aug 25, 2017 at 1:50 AM, Stuart Longland
<stuartl-3e+Fe6x+DsgJbe36r25VNhCuuivNXqWP@public.gmane.org> wrote:
> [Note: dropping vadimp-45czdsxZ+A5DPfheJLI6IQ@public.gmane.org as SMTP server complained about the
> DNS server returning NXDOMAIN. Apologies.]
> On 25/08/17 18:32, Linus Walleij wrote:
>> Gnah!
>> Whoever writes a slot-in replacement making the character device
>> take precendence wins lots of karma.
>
> What would such a replacement look like though?
See Linus's comments about using the existing kernel GPIO chardev
interface. It already supports requesting multiple GPIO line state
changes in a single request.
>
> Some sort of system whereby you can read/write single-line commands as
> if talking to a GPIO expander over a UART?
>
> Would you access the GPIOs one by one, or would you perhaps map them
> into a bitmap (maybe arbitrarily, up to 64-bits wide) and perform masked
> operations on the bitmap?
>
> I'm no fan of the sysfs GPIO interface, but it beats poking around at
> registers behind the kernel's back.
> --
> Stuart Longland (aka Redhatter, VK4MSL)
>
> I haven't lost my mind...
> ...it's backed up on a tape somewhere.
>
^ permalink raw reply
* Re: [patch v6 0/3] JTAG driver introduction
From: Rick Altherr @ 2017-08-25 16:52 UTC (permalink / raw)
To: Linus Walleij
Cc: Oleksandr Shamray,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Jiří Pírko, Arnd Bergmann,
system-sw-low-level-VPRAkNaXOzVWk0Htik3J/w, Greg KH,
OpenBMC Maillist,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
openocd-devel-owner-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f,
mec-WqBc5aa1uDFeoWH0uzbU5w, Rob Herring,
linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
vadimp-45czdsxZ+A5DPfheJLI6IQ, Tobias Klauser,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
In-Reply-To: <CACRpkdbozWaL0RXyZXjzxYK3JHiqYziSkTGSgGORdptX-rwR8A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On Fri, Aug 25, 2017 at 1:32 AM, Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
> On Thu, Aug 24, 2017 at 11:37 PM, Rick Altherr <raltherr-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> wrote:
>> On Thu, Aug 24, 2017 at 2:07 PM, Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
>>> On Tue, Aug 22, 2017 at 6:10 PM, Oleksandr Shamray
>>> <oleksandrs-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org> wrote:
>>>
>>>> SoC which are not equipped with JTAG master interface, can be built
>>>> on top of JTAG core driver infrastructure, by applying bit-banging of
>>>> TDI, TDO, TCK and TMS pins within the hardware specific driver.
>>>
>>> I guess you mean it should then use GPIO lines for bit-banging?
>>>
>>> I was wondering about how some JTAG clients like openOCD does
>>> this in some cases.
>>
>> Many common uses of OpenOCD leverage USB devices, such as FTDI FT232R,
>> that have a command queue for bitbanging operations. Managing these
>> via libusb is ugly but platform-agnostic.
>
> Incidentally, people are sending patches to expose the FTDI
> expanders as common GPIO chips under Linux, so we can
> internally in the kernel or from the usersapce character device
> access them as "some GPIOs".
>
I know my team at Google has an internal patch for exactly that. FTDI
expanders are complicated as they can be used as UART, GPIO, I2C, SPI
depending on configuration. Our project was using a mix of I2C and
GPIO so I directly my team to approach it as an MFD. I'd like to see
all of these use cases handled by the kernel but I understand the
other viewpoint of relying on libusb for cross-platform compatiblity.
>>> In my worst nightmare they export GPIO lines using
>>> the horrid ABI in /sys/gpio/*
>>
>> https://sourceforge.net/p/openocd/code/ci/v0.10.0/tree/src/jtag/drivers/sysfsgpio.c
>
> Gnah!
> Whoever writes a slot-in replacement making the character device
> take precendence wins lots of karma.
>
If they show up at Linux Plumbers or visit San Jose, I'll take them to
dinner. I didn't see any docs for the chardev in Documentation. I
_think_ I understand how it works from reading the relevant sections
of gpiolib.c but I can see how users end up using sysfs instead.
>> While that is certainly horrible (and slow), mapping in the GPIO
>> registers via /dev/mem strikes me as worse:
>>
>> https://sourceforge.net/p/openocd/code/ci/v0.10.0/tree/src/jtag/drivers/bcm2835gpio.c
>
> Yeah that is quite horrible.
>
> There were reasons to do things like that, but since we have
> developed .set_multiple() to hammer several lines in a register
> at once, the same efficiency can be achieved using the standard
> character device.
Agreed that that helps with user-space GPIO-based JTAG
implementations. The problem this patch series is trying to address
is for SoCs like the Aspeed AST2400/2500 that include a hardware
accelerated JTAG master. It _can_ be run in a pure-software mode
where it acts like GPIOs but the intended use case is to operate an
interrupt-driven state machine. That requires a higher-level
abstraction for managing the standard JTAG state machine. Similar to
GPIO .set_multiple, user-space feeding a JTAG kernel API a buffer of
JTAG state changes would be useful. That's how I recall OpenOCD's
internals working: run short (1-7?) state change sequences to move to
the next decision point. I know of at least one vendor pushing for
the use of JTAG on BMCs as a way to debug host processors in large
deployments instead of using dongles. I'm supportive of the adding a
JTAG driver abstraction. I haven't reviewed this patch series in
detail yet.
>
> Yours,
> Linus Walleij
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