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SubjectRe: [PATCH v3 7/7] watchdog: dw_wdt: Add DebugFS files
On Tue, May 26, 2020 at 06:41:23PM +0300, Serge Semin wrote:
> 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

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>
> 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);

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