Re: [PATCH v2 2/2] watchdog: sama5d4_wdt: addition of sam9x60 compatible watchdog

Guenter Roeck
2019-10-29T13:28:36Z

On Mon, Oct 21, 2019 at 09:14:09AM +0000, Eugen.Hristev@microchip.com wrote:
> From: Eugen Hristev <eugen.hristev@microchip.com>
>
> Add support for SAM9X60 WDT into sama5d4_wdt.
> This means that this driver will have a platform data that will
> hold differences.
> Added definitions of different bits.
> The ops functions will differentiate between the two hardware blocks.
>
> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
> ---
>
> Hello,
>
> This is a rework of the separate sam9x60 watchdog driver into a single driver
> that supports both hardware blocks (sam9x60 and sama5d4)
> This was done as suggested on the original patches on the mailing list.
>
> Thanks,
> Eugen
>
> drivers/watchdog/at91sam9_wdt.h | 14 +++++
> drivers/watchdog/sama5d4_wdt.c | 127 +++++++++++++++++++++++++++++++---------
> 2 files changed, 112 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/watchdog/at91sam9_wdt.h b/drivers/watchdog/at91sam9_wdt.h
> index 390941c..7a053fd 100644
> --- a/drivers/watchdog/at91sam9_wdt.h
> +++ b/drivers/watchdog/at91sam9_wdt.h
> @@ -20,7 +20,10 @@
> #define AT91_WDT_MR 0x04 /* Watchdog Mode Register */
> #define AT91_WDT_WDV (0xfff << 0) /* Counter Value */
> #define AT91_WDT_SET_WDV(x) ((x) & AT91_WDT_WDV)
> +#define AT91_SAM9X60_PERIODRST BIT(4) /* Period Reset */
> +#define AT91_SAM9X60_RPTHRST BIT(5) /* Minimum Restart Period */
> #define AT91_WDT_WDFIEN (1 << 12) /* Fault Interrupt Enable */
> +#define AT91_SAM9X60_WDDIS BIT(12) /* Disable */
> #define AT91_WDT_WDRSTEN (1 << 13) /* Reset Processor */
> #define AT91_WDT_WDRPROC (1 << 14) /* Timer Restart */
> #define AT91_WDT_WDDIS (1 << 15) /* Watchdog Disable */
> @@ -33,4 +36,15 @@
> #define AT91_WDT_WDUNF (1 << 0) /* Watchdog Underflow */
> #define AT91_WDT_WDERR (1 << 1) /* Watchdog Error */
>
> +#define AT91_SAM9X60_VR 0x08 /* Watchdog Timer Value Register */
> +
> +#define AT91_SAM9X60_WLR 0x0c
> +#define AT91_SAM9X60_COUNTER (0xfff << 0) /* Watchdog Period Value */
> +#define AT91_SAM9X60_SET_COUNTER(x) ((x) & AT91_SAM9X60_COUNTER)
> +
> +#define AT91_SAM9X60_IER 0x14 /* Interrupt Enable Register */
> +#define AT91_SAM9X60_PERINT BIT(0) /* Period Interrupt Enable */
> +#define AT91_SAM9X60_IDR 0x18 /* Interrupt Disable Register */
> +#define AT91_SAM9X60_ISR 0x1c /* Interrupt Status Register */
> +

Those tabs are getting messy, and the mix of BIT() and shift is messy too.
Mind cleaning it up a bit ? Especially, two tabs after #define doesn't really
add value (use two spaces), and use BIT() throughout or not at all.

> #endif
> diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c
> index d193a60..b92afd7 100644
> --- a/drivers/watchdog/sama5d4_wdt.c
> +++ b/drivers/watchdog/sama5d4_wdt.c
> @@ -2,7 +2,7 @@
> /*
> * Driver for Atmel SAMA5D4 Watchdog Timer
> *
> - * Copyright (C) 2015 Atmel Corporation
> + * Copyright (C) 2015-2019 Microchip Technology Inc. and its subsidiaries
> */
>
> #include <linux/delay.h>
> @@ -11,6 +11,7 @@
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <linux/of.h>
> +#include <linux/of_device.h>
> #include <linux/of_irq.h>
> #include <linux/platform_device.h>
> #include <linux/reboot.h>
> @@ -25,11 +26,18 @@
>
> #define WDT_SEC2TICKS(s) ((s) ? (((s) << 8) - 1) : 0)
>
> +struct sama5d4_wdt_data {
> + const unsigned int sam9x60_support;
> +};
> +
> struct sama5d4_wdt {
> - struct watchdog_device wdd;
> - void __iomem *reg_base;
> - u32 mr;
> - unsigned long last_ping;
> + struct watchdog_device wdd;
> + const struct sama5d4_wdt_data *data;
> + void __iomem *reg_base;
> + u32 mr;
> + u32 ir;
> + unsigned long last_ping;
> + unsigned int need_irq:1;

This can be a bool. Making it a bit just adds complexity to the code.

> };
>
> static int wdt_timeout;
> @@ -78,7 +86,12 @@ static int sama5d4_wdt_start(struct watchdog_device *wdd)
> {
> struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
>
> - wdt->mr &= ~AT91_WDT_WDDIS;
> + if (wdt->data->sam9x60_support) {
> + writel_relaxed(wdt->ir, wdt->reg_base + AT91_SAM9X60_IER);
> + wdt->mr &= ~AT91_SAM9X60_WDDIS;
> + } else {
> + wdt->mr &= ~AT91_WDT_WDDIS;
> + }
> wdt_write(wdt, AT91_WDT_MR, wdt->mr);
>
> return 0;
> @@ -88,7 +101,12 @@ static int sama5d4_wdt_stop(struct watchdog_device *wdd)
> {
> struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
>
> - wdt->mr |= AT91_WDT_WDDIS;
> + if (wdt->data->sam9x60_support) {
> + writel_relaxed(wdt->ir, wdt->reg_base + AT91_SAM9X60_IDR);
> + wdt->mr |= AT91_SAM9X60_WDDIS;
> + } else {
> + wdt->mr |= AT91_WDT_WDDIS;
> + }
> wdt_write(wdt, AT91_WDT_MR, wdt->mr);
>
> return 0;
> @@ -109,6 +127,14 @@ static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd,
> struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
> u32 value = WDT_SEC2TICKS(timeout);
>
> + if (wdt->data->sam9x60_support) {
> + wdt_write(wdt, AT91_SAM9X60_WLR,
> + AT91_SAM9X60_SET_COUNTER(value));
> +
> + wdd->timeout = timeout;
> + return 0;
> + }
> +
> wdt->mr &= ~AT91_WDT_WDV;
> wdt->mr |= AT91_WDT_SET_WDV(value);
>
> @@ -143,8 +169,14 @@ static const struct watchdog_ops sama5d4_wdt_ops = {
> static irqreturn_t sama5d4_wdt_irq_handler(int irq, void *dev_id)
> {
> struct sama5d4_wdt *wdt = platform_get_drvdata(dev_id);
> + u32 reg;
>
> - if (wdt_read(wdt, AT91_WDT_SR)) {
> + if (wdt->data->sam9x60_support)
> + reg = wdt_read(wdt, AT91_SAM9X60_ISR);
> + else
> + reg = wdt_read(wdt, AT91_WDT_SR);
> +
> + if (reg) {
> pr_crit("Atmel Watchdog Software Reset\n");
> emergency_restart();
> pr_crit("Reboot didn't succeed\n");
> @@ -157,13 +189,14 @@ static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt)
> {
> const char *tmp;
>
> - wdt->mr = AT91_WDT_WDDIS;
> + if (wdt->data->sam9x60_support)
> + wdt->mr = AT91_SAM9X60_WDDIS;
> + else
> + wdt->mr = AT91_WDT_WDDIS;
>
> if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
> !strcmp(tmp, "software"))
> - wdt->mr |= AT91_WDT_WDFIEN;
> - else
> - wdt->mr |= AT91_WDT_WDRSTEN;
> + wdt->need_irq = 1;
>
> if (of_property_read_bool(np, "atmel,idle-halt"))
> wdt->mr |= AT91_WDT_WDIDLEHLT;
> @@ -176,21 +209,46 @@ static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt)
>
> static int sama5d4_wdt_init(struct sama5d4_wdt *wdt)
> {
> - u32 reg;
> + u32 reg, val;
> +
> + val = WDT_SEC2TICKS(WDT_DEFAULT_TIMEOUT);
> /*
> * When booting and resuming, the bootloader may have changed the
> * watchdog configuration.
> * If the watchdog is already running, we can safely update it.
> * Else, we have to disable it properly.
> */
> - if (wdt_enabled) {
> - wdt_write_nosleep(wdt, AT91_WDT_MR, wdt->mr);
> - } else {
> + if (!wdt_enabled) {
> reg = wdt_read(wdt, AT91_WDT_MR);
> - if (!(reg & AT91_WDT_WDDIS))
> + if (wdt->data->sam9x60_support && (!(reg & AT91_SAM9X60_WDDIS)))
> + wdt_write_nosleep(wdt, AT91_WDT_MR,
> + reg | AT91_SAM9X60_WDDIS);
> + else if (!wdt->data->sam9x60_support &&
> + (!(reg & AT91_WDT_WDDIS)))
> wdt_write_nosleep(wdt, AT91_WDT_MR,
> reg | AT91_WDT_WDDIS);
> }
> +
> + if (wdt->data->sam9x60_support) {
> + if (wdt->need_irq)
> + wdt->ir = AT91_SAM9X60_PERINT;
> + else
> + wdt->mr |= AT91_SAM9X60_PERIODRST;
> +
> + wdt_write(wdt, AT91_SAM9X60_IER, wdt->ir);
> + wdt_write(wdt, AT91_SAM9X60_WLR, AT91_SAM9X60_SET_COUNTER(val));
> + } else {
> + wdt->mr |= AT91_WDT_SET_WDD(WDT_SEC2TICKS(MAX_WDT_TIMEOUT));
> + wdt->mr |= AT91_WDT_SET_WDV(val);
> +
> + if (wdt->need_irq)
> + wdt->mr |= AT91_WDT_WDFIEN;
> + else
> + wdt->mr |= AT91_WDT_WDRSTEN;
> + }
> +
> + wdt_write_nosleep(wdt, AT91_WDT_MR, wdt->mr);
> +
> return 0;
> }
>
> @@ -201,13 +259,14 @@ static int sama5d4_wdt_probe(struct platform_device *pdev)
> struct sama5d4_wdt *wdt;
> void __iomem *regs;
> u32 irq = 0;
> - u32 timeout;
> int ret;
>
> wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
> if (!wdt)
> return -ENOMEM;
>
> + wdt->data = of_device_get_match_data(&pdev->dev);
> +
> wdd = &wdt->wdd;
> wdd->timeout = WDT_DEFAULT_TIMEOUT;
> wdd->info = &sama5d4_wdt_info;
> @@ -224,15 +283,17 @@ static int sama5d4_wdt_probe(struct platform_device *pdev)
>
> wdt->reg_base = regs;
>
> - irq = irq_of_parse_and_map(dev->of_node, 0);
> - if (!irq)
> - dev_warn(dev, "failed to get IRQ from DT\n");
> -
> ret = of_sama5d4_wdt_init(dev->of_node, wdt);
> if (ret)
> return ret;
>
> - if ((wdt->mr & AT91_WDT_WDFIEN) && irq) {
> + irq = irq_of_parse_and_map(dev->of_node, 0);
> + if (!irq) {
> + dev_warn(dev, "failed to get IRQ from DT\n");
> + wdt->need_irq = 0;

Does it make sense to ignore that ?

> + }
> +
> + if (wdt->need_irq) {
> ret = devm_request_irq(dev, irq, sama5d4_wdt_irq_handler,
> IRQF_SHARED | IRQF_IRQPOLL |
> IRQF_NO_SUSPEND, pdev->name, pdev);
> @@ -244,11 +305,6 @@ static int sama5d4_wdt_probe(struct platform_device *pdev)
>
> watchdog_init_timeout(wdd, wdt_timeout, dev);
>
> - timeout = WDT_SEC2TICKS(wdd->timeout);
> -
> - wdt->mr |= AT91_WDT_SET_WDD(WDT_SEC2TICKS(MAX_WDT_TIMEOUT));
> - wdt->mr |= AT91_WDT_SET_WDV(timeout);
> -
> ret = sama5d4_wdt_init(wdt);
> if (ret)
> return ret;
> @@ -268,8 +324,21 @@ static int sama5d4_wdt_probe(struct platform_device *pdev)
> return 0;
> }
>
> +static struct sama5d4_wdt_data sama5d4_config;
> +
> +static struct sama5d4_wdt_data sam9x60_config = {
> + .sam9x60_support = 1,
> +};

Unless there is reason to believe that there will be other
configuration data, please just assign the flag value directly
to .data and add a variable to struct sama5d4_wdt to access it.
Please make that variable a bool.

> +
> static const struct of_device_id sama5d4_wdt_of_match[] = {
> - { .compatible = "atmel,sama5d4-wdt", },
> + {
> + .compatible = "atmel,sama5d4-wdt",
> + .data = &sama5d4_config,
> + },
> + {
> + .compatible = "microchip,sam9x60-wdt",
> + .data = &sam9x60_config,
> + },
> { }
> };
> MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match);