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Subject[PATCH v3 09/12] watchdog: s3c2410: Cleanup PMU related code
Date
Now that PMU enablement code was extended for new Exynos SoCs, it
doesn't look very cohesive and consistent anymore. Do a bit of renaming,
grouping and style changes, to make it look good again. While at it, add
quirks documentation as well.

No functional change, just a refactoring commit.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
---
Changes in v3:
- Added quirks documentation
- Added R-b tag by Krzysztof Kozlowski

Changes in v2:
- (none): it's a new patch

drivers/watchdog/s3c2410_wdt.c | 83 ++++++++++++++++++++++++----------
1 file changed, 58 insertions(+), 25 deletions(-)

diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
index ec341c876225..f211be8bf976 100644
--- a/drivers/watchdog/s3c2410_wdt.c
+++ b/drivers/watchdog/s3c2410_wdt.c
@@ -56,17 +56,51 @@
#define EXYNOS5_RST_STAT_REG_OFFSET 0x0404
#define EXYNOS5_WDT_DISABLE_REG_OFFSET 0x0408
#define EXYNOS5_WDT_MASK_RESET_REG_OFFSET 0x040c
-#define QUIRK_HAS_PMU_CONFIG (1 << 0)
-#define QUIRK_HAS_RST_STAT (1 << 1)
-#define QUIRK_HAS_WTCLRINT_REG (1 << 2)
+
+/**
+ * Quirk flags for different Samsung watchdog IP-cores.
+ *
+ * This driver supports multiple Samsung SoCs, each of which might have
+ * different set of registers and features supported. As watchdog block
+ * sometimes requires modifying PMU registers for proper functioning, register
+ * differences in both watchdog and PMU IP-cores should be accounted for. Quirk
+ * flags described below serve the purpose of telling the driver about mentioned
+ * SoC traits, and can be specified in driver data for each particular supported
+ * device.
+ *
+ * %QUIRK_HAS_WTCLRINT_REG: Watchdog block has WTCLRINT register. It's used to
+ * clear the interrupt once the interrupt service routine is complete. It's
+ * write-only, writing any values to this register clears the interrupt, but
+ * reading is not permitted.
+ *
+ * %QUIRK_HAS_PMU_MASK_RESET: PMU block has the register for disabling/enabling
+ * WDT reset request. On old SoCs it's usually called MASK_WDT_RESET_REQUEST,
+ * new SoCs have CLUSTERx_NONCPU_INT_EN register, which 'mask_bit' value is
+ * inverted compared to the former one.
+ *
+ * %QUIRK_HAS_PMU_RST_STAT: PMU block has RST_STAT (reset status) register,
+ * which contains bits indicating the reason for most recent CPU reset. If
+ * present, driver will use this register to check if previous reboot was due to
+ * watchdog timer reset.
+ *
+ * %QUIRK_HAS_PMU_AUTO_DISABLE: PMU block has AUTOMATIC_WDT_RESET_DISABLE
+ * register. If 'mask_bit' bit is set, PMU will disable WDT reset when
+ * corresponding processor is in reset state.
+ *
+ * %QUIRK_HAS_PMU_CNT_EN: PMU block has some register (e.g. CLUSTERx_NONCPU_OUT)
+ * with "watchdog counter enable" bit. That bit should be set to make watchdog
+ * counter running.
+ */
+#define QUIRK_HAS_WTCLRINT_REG (1 << 0)
+#define QUIRK_HAS_PMU_MASK_RESET (1 << 1)
+#define QUIRK_HAS_PMU_RST_STAT (1 << 2)
#define QUIRK_HAS_PMU_AUTO_DISABLE (1 << 3)
#define QUIRK_HAS_PMU_CNT_EN (1 << 4)

/* These quirks require that we have a PMU register map */
-#define QUIRKS_HAVE_PMUREG (QUIRK_HAS_PMU_CONFIG | \
- QUIRK_HAS_RST_STAT | \
- QUIRK_HAS_PMU_AUTO_DISABLE | \
- QUIRK_HAS_PMU_CNT_EN)
+#define QUIRKS_HAVE_PMUREG \
+ (QUIRK_HAS_PMU_MASK_RESET | QUIRK_HAS_PMU_RST_STAT | \
+ QUIRK_HAS_PMU_AUTO_DISABLE | QUIRK_HAS_PMU_CNT_EN)

static bool nowayout = WATCHDOG_NOWAYOUT;
static int tmr_margin;
@@ -146,8 +180,8 @@ static const struct s3c2410_wdt_variant drv_data_exynos5250 = {
.mask_bit = 20,
.rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
.rst_stat_bit = 20,
- .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \
- | QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_AUTO_DISABLE,
+ .quirks = QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_MASK_RESET | \
+ QUIRK_HAS_PMU_RST_STAT | QUIRK_HAS_PMU_AUTO_DISABLE,
};

static const struct s3c2410_wdt_variant drv_data_exynos5420 = {
@@ -156,8 +190,8 @@ static const struct s3c2410_wdt_variant drv_data_exynos5420 = {
.mask_bit = 0,
.rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
.rst_stat_bit = 9,
- .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \
- | QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_AUTO_DISABLE,
+ .quirks = QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_MASK_RESET | \
+ QUIRK_HAS_PMU_RST_STAT | QUIRK_HAS_PMU_AUTO_DISABLE,
};

static const struct s3c2410_wdt_variant drv_data_exynos7 = {
@@ -166,8 +200,8 @@ static const struct s3c2410_wdt_variant drv_data_exynos7 = {
.mask_bit = 23,
.rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
.rst_stat_bit = 23, /* A57 WDTRESET */
- .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \
- | QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_AUTO_DISABLE,
+ .quirks = QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_MASK_RESET | \
+ QUIRK_HAS_PMU_RST_STAT | QUIRK_HAS_PMU_AUTO_DISABLE,
};

static const struct of_device_id s3c2410_wdt_match[] = {
@@ -253,24 +287,24 @@ static int s3c2410wdt_enable_counter(struct s3c2410_wdt *wdt, bool en)
return ret;
}

-static int s3c2410wdt_mask_and_disable_reset(struct s3c2410_wdt *wdt, bool mask)
+static int s3c2410wdt_enable(struct s3c2410_wdt *wdt, bool en)
{
int ret;

if (wdt->drv_data->quirks & QUIRK_HAS_PMU_AUTO_DISABLE) {
- ret = s3c2410wdt_disable_wdt_reset(wdt, mask);
+ ret = s3c2410wdt_disable_wdt_reset(wdt, !en);
if (ret < 0)
return ret;
}

- if (wdt->drv_data->quirks & QUIRK_HAS_PMU_CONFIG) {
- ret = s3c2410wdt_mask_wdt_reset(wdt, mask);
+ if (wdt->drv_data->quirks & QUIRK_HAS_PMU_MASK_RESET) {
+ ret = s3c2410wdt_mask_wdt_reset(wdt, !en);
if (ret < 0)
return ret;
}

if (wdt->drv_data->quirks & QUIRK_HAS_PMU_CNT_EN) {
- ret = s3c2410wdt_enable_counter(wdt, !mask);
+ ret = s3c2410wdt_enable_counter(wdt, en);
if (ret < 0)
return ret;
}
@@ -531,7 +565,7 @@ static inline unsigned int s3c2410wdt_get_bootstatus(struct s3c2410_wdt *wdt)
unsigned int rst_stat;
int ret;

- if (!(wdt->drv_data->quirks & QUIRK_HAS_RST_STAT))
+ if (!(wdt->drv_data->quirks & QUIRK_HAS_PMU_RST_STAT))
return 0;

ret = regmap_read(wdt->pmureg, wdt->drv_data->rst_stat_reg, &rst_stat);
@@ -672,7 +706,7 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
if (ret)
goto err_cpufreq;

- ret = s3c2410wdt_mask_and_disable_reset(wdt, false);
+ ret = s3c2410wdt_enable(wdt, true);
if (ret < 0)
goto err_unregister;

@@ -707,7 +741,7 @@ static int s3c2410wdt_remove(struct platform_device *dev)
int ret;
struct s3c2410_wdt *wdt = platform_get_drvdata(dev);

- ret = s3c2410wdt_mask_and_disable_reset(wdt, true);
+ ret = s3c2410wdt_enable(wdt, false);
if (ret < 0)
return ret;

@@ -724,8 +758,7 @@ static void s3c2410wdt_shutdown(struct platform_device *dev)
{
struct s3c2410_wdt *wdt = platform_get_drvdata(dev);

- s3c2410wdt_mask_and_disable_reset(wdt, true);
-
+ s3c2410wdt_enable(wdt, false);
s3c2410wdt_stop(&wdt->wdt_device);
}

@@ -740,7 +773,7 @@ static int s3c2410wdt_suspend(struct device *dev)
wdt->wtcon_save = readl(wdt->reg_base + S3C2410_WTCON);
wdt->wtdat_save = readl(wdt->reg_base + S3C2410_WTDAT);

- ret = s3c2410wdt_mask_and_disable_reset(wdt, true);
+ ret = s3c2410wdt_enable(wdt, false);
if (ret < 0)
return ret;

@@ -760,7 +793,7 @@ static int s3c2410wdt_resume(struct device *dev)
writel(wdt->wtdat_save, wdt->reg_base + S3C2410_WTCNT);/* Reset count */
writel(wdt->wtcon_save, wdt->reg_base + S3C2410_WTCON);

- ret = s3c2410wdt_mask_and_disable_reset(wdt, false);
+ ret = s3c2410wdt_enable(wdt, true);
if (ret < 0)
return ret;

--
2.30.2
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