Re: [PATCH 2/3] watchdog: qcom: add option for standalone watchdog not in timer block

[Guenter Roeck <linux@roeck-us.net>]

On 06/27/2016 04:26 PM, Thomas Pedersen wrote:
> From: Matthew McClintock <mmcclint@codeaurora.org>
>
> Commit 0dfd582e026a ("watchdog: qcom: use timer devicetree binding") moved
> to use the watchdog as a subset timer register block. Some devices have the
> watchdog completely standalone with slightly different register offsets as
> well so let's account for the differences here.
>
> Signed-off-by: Matthew McClintock <mmcclint@codeaurora.org>
> ---
>   drivers/watchdog/qcom-wdt.c | 73 ++++++++++++++++++++++++++++++++-------------
>   1 file changed, 52 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
> index a043fa4..70e42ed 100644
> --- a/drivers/watchdog/qcom-wdt.c
> +++ b/drivers/watchdog/qcom-wdt.c
> @@ -19,18 +19,40 @@
>   #include <linux/platform_device.h>
>   #include <linux/watchdog.h>
>
> -#define WDT_RST		0x38
> -#define WDT_EN		0x40
> -#define WDT_STS		0x44
> -#define WDT_BITE_TIME	0x5C
> +enum wdt_reg {
> +	WDT_RST,
> +	WDT_EN,
> +	WDT_STS,
> +	WDT_BITE_TIME,
> +};
> +
> +static const u32 reg_offset_data_apcs_tmr[] = {
> +	[WDT_RST] = 0x38,
> +	[WDT_EN] = 0x40,
> +	[WDT_STS] = 0x44,
> +	[WDT_BITE_TIME] = 0x5C,
> +};
> +
> +static const u32 reg_offset_data_kpss[] = {
> +	[WDT_RST] = 0x4,
> +	[WDT_EN] = 0x8,
> +	[WDT_STS] = 0xC,
> +	[WDT_BITE_TIME] = 0x14,
> +};
>
>   struct qcom_wdt {
>   	struct watchdog_device	wdd;
>   	struct clk		*clk;
>   	unsigned long		rate;
>   	void __iomem		*base;
> +	const u32		*layout;
>   };
>
> +static void __iomem *wdt_addr(struct qcom_wdt *wdt, enum wdt_reg reg)
> +{
> +	return wdt->base + wdt->layout[reg];
> +}
> +
>   static inline
>   struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd)
>   {
> @@ -41,10 +63,10 @@ static int qcom_wdt_start(struct watchdog_device *wdd)
>   {
>   	struct qcom_wdt *wdt = to_qcom_wdt(wdd);
>
> -	writel(0, wdt->base + WDT_EN);
> -	writel(1, wdt->base + WDT_RST);
> -	writel(wdd->timeout * wdt->rate, wdt->base + WDT_BITE_TIME);
> -	writel(1, wdt->base + WDT_EN);
> +	writel(0, wdt_addr(wdt, WDT_EN));
> +	writel(1, wdt_addr(wdt, WDT_RST));
> +	writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
> +	writel(1, wdt_addr(wdt, WDT_EN));
>   	return 0;
>   }
>
> @@ -52,7 +74,7 @@ static int qcom_wdt_stop(struct watchdog_device *wdd)
>   {
>   	struct qcom_wdt *wdt = to_qcom_wdt(wdd);
>
> -	writel(0, wdt->base + WDT_EN);
> +	writel(0, wdt_addr(wdt, WDT_EN));
>   	return 0;
>   }
>
> @@ -60,7 +82,7 @@ static int qcom_wdt_ping(struct watchdog_device *wdd)
>   {
>   	struct qcom_wdt *wdt = to_qcom_wdt(wdd);
>
> -	writel(1, wdt->base + WDT_RST);
> +	writel(1, wdt_addr(wdt, WDT_RST));
>   	return 0;
>   }
>
> @@ -83,10 +105,10 @@ static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action,
>   	 */
>   	timeout = 128 * wdt->rate / 1000;
>
> -	writel(0, wdt->base + WDT_EN);
> -	writel(1, wdt->base + WDT_RST);
> -	writel(timeout, wdt->base + WDT_BITE_TIME);
> -	writel(1, wdt->base + WDT_EN);
> +	writel(0, wdt_addr(wdt, WDT_EN));
> +	writel(1, wdt_addr(wdt, WDT_RST));
> +	writel(timeout, wdt_addr(wdt, WDT_BITE_TIME));
> +	writel(1, wdt_addr(wdt, WDT_EN));
>
>   	/*
>   	 * Actually make sure the above sequence hits hardware before sleeping.
> @@ -114,14 +136,29 @@ static const struct watchdog_info qcom_wdt_info = {
>   	.identity	= KBUILD_MODNAME,
>   };
>
> +static const struct of_device_id qcom_wdt_of_table[] = {
> +	{ .compatible = "qcom,kpss-timer", .data = reg_offset_data_apcs_tmr },
> +	{ .compatible = "qcom,scss-timer", .data = reg_offset_data_apcs_tmr },
> +	{ .compatible = "qcom,kpss-standalone", .data = &reg_offset_data_kpss},
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, qcom_wdt_of_table);
> +
>   static int qcom_wdt_probe(struct platform_device *pdev)
>   {
>   	struct qcom_wdt *wdt;
>   	struct resource *res;
>   	struct device_node *np = pdev->dev.of_node;
> +	const struct of_device_id *match;
>   	u32 percpu_offset;
>   	int ret;
>
> +	match = of_match_node(qcom_wdt_of_table, np);
> +	if (!match) {
> +		dev_err(&pdev->dev, "Unsupported QCOM WDT module\n");
> +		return -ENODEV;
> +	}
> +
>   	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
>   	if (!wdt)
>   		return -ENOMEM;
> @@ -172,6 +209,7 @@ static int qcom_wdt_probe(struct platform_device *pdev)
>   	wdt->wdd.min_timeout = 1;
>   	wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
>   	wdt->wdd.parent = &pdev->dev;
> +	wdt->layout = match->data;
>
>   	if (readl(wdt->base + WDT_STS) & 1)
>   		wdt->wdd.bootstatus = WDIOF_CARDRESET;
> @@ -207,13 +245,6 @@ static int qcom_wdt_remove(struct platform_device *pdev)
>   	return 0;
>   }
>
> -static const struct of_device_id qcom_wdt_of_table[] = {
> -	{ .compatible = "qcom,kpss-timer" },
> -	{ .compatible = "qcom,scss-timer" },
> -	{ },
> -};
> -MODULE_DEVICE_TABLE(of, qcom_wdt_of_table);
> -

Earlier comment from Stephen Boyd:

Leave this here and use of_device_get_match_data() in probe
instead.

>   static struct platform_driver qcom_watchdog_driver = {
>   	.probe	= qcom_wdt_probe,
>   	.remove	= qcom_wdt_remove,
>