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Subject[PATCH v3 7/7] watchdog: dw_wdt: Add DebugFS files
Date
For the sake of the easier device-driver debug procedure, we added a
DebugFS file with the controller registers state. It's available only if
kernel is configured with DebugFS support.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org

---

Changelog v2:
- Rearrange SoBs.
- Discard timeout/pretimeout/ping/enable DebugFS nodes. Registers state
dump node is only left.
---
drivers/watchdog/dw_wdt.c | 68 +++++++++++++++++++++++++++++++++++++++
1 file changed, 68 insertions(+)

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index 3cd7c485cd70..012681baaa6d 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -28,6 +28,7 @@
#include <linux/platform_device.h>
#include <linux/reset.h>
#include <linux/watchdog.h>
+#include <linux/debugfs.h>

#define WDOG_CONTROL_REG_OFFSET 0x00
#define WDOG_CONTROL_REG_WDT_EN_MASK 0x01
@@ -39,8 +40,14 @@
#define WDOG_COUNTER_RESTART_KICK_VALUE 0x76
#define WDOG_INTERRUPT_STATUS_REG_OFFSET 0x10
#define WDOG_INTERRUPT_CLEAR_REG_OFFSET 0x14
+#define WDOG_COMP_PARAMS_5_REG_OFFSET 0xe4
+#define WDOG_COMP_PARAMS_4_REG_OFFSET 0xe8
+#define WDOG_COMP_PARAMS_3_REG_OFFSET 0xec
+#define WDOG_COMP_PARAMS_2_REG_OFFSET 0xf0
#define WDOG_COMP_PARAMS_1_REG_OFFSET 0xf4
#define WDOG_COMP_PARAMS_1_USE_FIX_TOP BIT(6)
+#define WDOG_COMP_VERSION_REG_OFFSET 0xf8
+#define WDOG_COMP_TYPE_REG_OFFSET 0xfc

/* There are sixteen TOPs (timeout periods) that can be set in the watchdog. */
#define DW_WDT_NUM_TOPS 16
@@ -85,6 +92,10 @@ struct dw_wdt {
/* Save/restore */
u32 control;
u32 timeout;
+
+#ifdef CONFIG_DEBUG_FS
+ struct dentry *dbgfs_dir;
+#endif
};

#define to_dw_wdt(wdd) container_of(wdd, struct dw_wdt, wdd)
@@ -484,6 +495,59 @@ static int dw_wdt_init_timeouts(struct dw_wdt *dw_wdt, struct device *dev)
return 0;
}

+#ifdef CONFIG_DEBUG_FS
+
+#define DW_WDT_DBGFS_REG(_name, _off) \
+{ \
+ .name = _name, \
+ .offset = _off \
+}
+
+static const struct debugfs_reg32 dw_wdt_dbgfs_regs[] = {
+ DW_WDT_DBGFS_REG("cr", WDOG_CONTROL_REG_OFFSET),
+ DW_WDT_DBGFS_REG("torr", WDOG_TIMEOUT_RANGE_REG_OFFSET),
+ DW_WDT_DBGFS_REG("ccvr", WDOG_CURRENT_COUNT_REG_OFFSET),
+ DW_WDT_DBGFS_REG("crr", WDOG_COUNTER_RESTART_REG_OFFSET),
+ DW_WDT_DBGFS_REG("stat", WDOG_INTERRUPT_STATUS_REG_OFFSET),
+ DW_WDT_DBGFS_REG("param5", WDOG_COMP_PARAMS_5_REG_OFFSET),
+ DW_WDT_DBGFS_REG("param4", WDOG_COMP_PARAMS_4_REG_OFFSET),
+ DW_WDT_DBGFS_REG("param3", WDOG_COMP_PARAMS_3_REG_OFFSET),
+ DW_WDT_DBGFS_REG("param2", WDOG_COMP_PARAMS_2_REG_OFFSET),
+ DW_WDT_DBGFS_REG("param1", WDOG_COMP_PARAMS_1_REG_OFFSET),
+ DW_WDT_DBGFS_REG("version", WDOG_COMP_VERSION_REG_OFFSET),
+ DW_WDT_DBGFS_REG("type", WDOG_COMP_TYPE_REG_OFFSET)
+};
+
+static void dw_wdt_dbgfs_init(struct dw_wdt *dw_wdt)
+{
+ struct device *dev = dw_wdt->wdd.parent;
+ struct debugfs_regset32 *regset;
+
+ regset = devm_kzalloc(dev, sizeof(*regset), GFP_KERNEL);
+ if (!regset)
+ return;
+
+ regset->regs = dw_wdt_dbgfs_regs;
+ regset->nregs = ARRAY_SIZE(dw_wdt_dbgfs_regs);
+ regset->base = dw_wdt->regs;
+
+ dw_wdt->dbgfs_dir = debugfs_create_dir(dev_name(dev), NULL);
+
+ debugfs_create_regset32("registers", 0444, dw_wdt->dbgfs_dir, regset);
+}
+
+static void dw_wdt_dbgfs_clear(struct dw_wdt *dw_wdt)
+{
+ debugfs_remove_recursive(dw_wdt->dbgfs_dir);
+}
+
+#else /* !CONFIG_DEBUG_FS */
+
+static void dw_wdt_dbgfs_init(struct dw_wdt *dw_wdt) {}
+static void dw_wdt_dbgfs_clear(struct dw_wdt *dw_wdt) {}
+
+#endif /* !CONFIG_DEBUG_FS */
+
static int dw_wdt_drv_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -607,6 +671,8 @@ static int dw_wdt_drv_probe(struct platform_device *pdev)
if (ret)
goto out_disable_pclk;

+ dw_wdt_dbgfs_init(dw_wdt);
+
return 0;

out_disable_pclk:
@@ -621,6 +687,8 @@ static int dw_wdt_drv_remove(struct platform_device *pdev)
{
struct dw_wdt *dw_wdt = platform_get_drvdata(pdev);

+ dw_wdt_dbgfs_clear(dw_wdt);
+
watchdog_unregister_device(&dw_wdt->wdd);
reset_control_assert(dw_wdt->rst);
clk_disable_unprepare(dw_wdt->pclk);
--
2.26.2
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