[PATCH v2 12/12] watchdog: s3c2410: Add Exynos850 support
Sam Protsenko
semen.protsenko at linaro.org
Sun Nov 7 08:17:29 PST 2021
On Tue, 2 Nov 2021 at 12:27, Krzysztof Kozlowski
<krzysztof.kozlowski at canonical.com> wrote:
>
> On 31/10/2021 13:22, Sam Protsenko wrote:
> > Exynos850 is a bit different from SoCs already supported in WDT driver:
> > - AUTOMATIC_WDT_RESET_DISABLE register is removed, so its value is
> > always 0; .disable_auto_reset callback is not set for that reason
> > - MASK_WDT_RESET_REQUEST register is replaced with
> > CLUSTERx_NONCPU_IN_EN register; instead of masking (disabling) WDT
> > reset interrupt it's now enabled with the same value; .mask_reset
> > callback is reused for that functionality though
> > - To make WDT functional, WDT counter needs to be enabled in
> > CLUSTERx_NONCPU_OUT register; it's done using .enable_counter
> > callback
> >
> > Also Exynos850 has two CPU clusters, each has its own dedicated WDT
> > instance. Different PMU registers and bits are used for each cluster. So
> > driver data is now modified in probe, adding needed info depending on
> > cluster index passed from device tree.
> >
> > Signed-off-by: Sam Protsenko <semen.protsenko at linaro.org>
> > ---
> > Changes in v2:
> > - Used single compatible for Exynos850, populating missing driver data in
> > probe
> > - Added "index" property to specify CPU cluster index
> >
> > drivers/watchdog/s3c2410_wdt.c | 68 +++++++++++++++++++++++++++++++++-
> > 1 file changed, 66 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
> > index 8fdda2ede1c3..457b725c30ac 100644
> > --- a/drivers/watchdog/s3c2410_wdt.c
> > +++ b/drivers/watchdog/s3c2410_wdt.c
> > @@ -56,6 +56,14 @@
> > #define EXYNOS5_RST_STAT_REG_OFFSET 0x0404
> > #define EXYNOS5_WDT_DISABLE_REG_OFFSET 0x0408
> > #define EXYNOS5_WDT_MASK_RESET_REG_OFFSET 0x040c
> > +#define EXYNOS850_CLUSTER0_NONCPU_OUT 0x1220
> > +#define EXYNOS850_CLUSTER0_NONCPU_INT_EN 0x1244
> > +#define EXYNOS850_CLUSTER1_NONCPU_OUT 0x1620
> > +#define EXYNOS850_CLUSTER1_NONCPU_INT_EN 0x1644
> > +
> > +#define EXYNOS850_CLUSTER0_WDTRESET_BIT 24
> > +#define EXYNOS850_CLUSTER1_WDTRESET_BIT 23
> > +
> > #define QUIRK_HAS_WTCLRINT_REG (1 << 0)
> > #define QUIRK_HAS_PMU_MASK_RESET (1 << 1)
> > #define QUIRK_HAS_PMU_RST_STAT (1 << 2)
> > @@ -171,6 +179,21 @@ static const struct s3c2410_wdt_variant drv_data_exynos7 = {
> > QUIRK_HAS_PMU_RST_STAT | QUIRK_HAS_PMU_AUTO_DISABLE,
> > };
> >
> > +static const struct s3c2410_wdt_variant drv_data_exynos850 = {
> > + /*
> > + * Next fields will be set in probe(), based on cluster index:
> > + * - .mask_reset_reg
> > + * - .rst_stat_bit
> > + * - .cnt_en_reg
> > + */
> > + .mask_reset_inv = true,
> > + .mask_bit = 2,
> > + .rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
> > + .cnt_en_bit = 7,
> > + .quirks = QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_MASK_RESET | \
> > + QUIRK_HAS_PMU_RST_STAT | QUIRK_HAS_PMU_CNT_EN,
> > +};
> > +
> > static const struct of_device_id s3c2410_wdt_match[] = {
> > { .compatible = "samsung,s3c2410-wdt",
> > .data = &drv_data_s3c2410 },
> > @@ -182,6 +205,8 @@ static const struct of_device_id s3c2410_wdt_match[] = {
> > .data = &drv_data_exynos5420 },
> > { .compatible = "samsung,exynos7-wdt",
> > .data = &drv_data_exynos7 },
> > + { .compatible = "samsung,exynos850-wdt",
> > + .data = &drv_data_exynos850 },
> > {},
> > };
> > MODULE_DEVICE_TABLE(of, s3c2410_wdt_match);
> > @@ -548,15 +573,51 @@ static inline const struct s3c2410_wdt_variant *
> > s3c2410_get_wdt_drv_data(struct platform_device *pdev)
> > {
> > const struct s3c2410_wdt_variant *variant;
> > + struct s3c2410_wdt_variant *data;
> > + struct device *dev = &pdev->dev;
> >
> > - variant = of_device_get_match_data(&pdev->dev);
> > + variant = of_device_get_match_data(dev);
> > if (!variant) {
> > /* Device matched by platform_device_id */
> > variant = (struct s3c2410_wdt_variant *)
> > platform_get_device_id(pdev)->driver_data;
> > }
> >
> > - return variant;
> > + /* Have to copy driver data over to keep its const qualifier intact */
> > + data = devm_kmemdup(dev, variant, sizeof(*variant), GFP_KERNEL);
> > + if (!data)
> > + return NULL;
> > +
> > + /* Populate missing fields for Exynos850 w.r.t. cluster index */
> > + if (variant == &drv_data_exynos850) {
> > + u32 index;
> > + int err;
>
> Another approach is to:
> 1. Define two variants for Exynos850 (s3c2410_wdt_variants), kind of
> like before,
> 2. if (variant == &drv_data_exynos850)
> a. Read the index
> b. If index is 0, return first variant,
> c. If index is 1, return the second variant,
> d. Else - NULL.
>
> This way you won't need to copy the memory on the fly, just use
> different const data. Benefits: less memory allocations, entire drvdata
> set in one place (so nicely visible), drvdata populated safely via const.
>
That's definitely better. Not sure how I missed that. Anyway, thanks
for review. Will send v3 soon, addressing all your comments (except
the one about src_clk in PATCH 10/12 -- need to discuss it further, I
guess).
> > +
> > + err = of_property_read_u32(dev->of_node, "samsung,index",
> > + &index);
> > + if (err) {
> > + dev_err(dev, "failed to get cluster index\n");
> > + return NULL;
> > + }
> > +
> > + switch (index) {
> > + case 0:
> > + data->mask_reset_reg = EXYNOS850_CLUSTER0_NONCPU_INT_EN;
> > + data->rst_stat_bit = EXYNOS850_CLUSTER0_WDTRESET_BIT;
> > + data->cnt_en_reg = EXYNOS850_CLUSTER0_NONCPU_OUT;
> > + break;
> > + case 1:
> > + data->mask_reset_reg = EXYNOS850_CLUSTER1_NONCPU_INT_EN;
> > + data->rst_stat_bit = EXYNOS850_CLUSTER1_WDTRESET_BIT;
> > + data->cnt_en_reg = EXYNOS850_CLUSTER1_NONCPU_OUT;
> > + break;
> > + default:
> > + dev_err(dev, "wrong cluster index: %u\n", index);
> > + return NULL;
> > + }
> > + }
> > +
> > + return data;
> > }
> >
> > static int s3c2410wdt_probe(struct platform_device *pdev)
> > @@ -576,6 +637,9 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
> > wdt->wdt_device = s3c2410_wdd;
> >
> > wdt->drv_data = s3c2410_get_wdt_drv_data(pdev);
> > + if (!wdt->drv_data)
> > + return -EINVAL;
> > +
> > if (wdt->drv_data->quirks & QUIRKS_HAVE_PMUREG) {
> > wdt->pmureg = syscon_regmap_lookup_by_phandle(dev->of_node,
> > "samsung,syscon-phandle");
> >
>
>
> Best regards,
> Krzysztof
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