Hi Guenter,
Many thanks for your help, I will push corrections to V4.
Best regards
On 03/29/2017 05:15 AM, Guenter Roeck wrote:
> On 03/22/2017 08:04 AM, Yannick Fertre wrote:
>> This patch adds IWDG (Independent WatchDoG) support for STM32 platform.
>>
>> Change-Id: Iab218745fc25566f12558fae7f52e2f8c21db74e
>
> No gerrit tags, please.
>
>> Signed-off-by: Yannick FERTRE <yannick.fertre@xxxxxx>
>> ---
>> drivers/watchdog/Kconfig | 11 ++
>> drivers/watchdog/Makefile | 1 +
>> drivers/watchdog/stm32_iwdg.c | 289
>> ++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 301 insertions(+)
>> create mode 100644 drivers/watchdog/stm32_iwdg.c
>>
>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> index 52a70ee..d9745a5 100644
>> --- a/drivers/watchdog/Kconfig
>> +++ b/drivers/watchdog/Kconfig
>> @@ -744,6 +744,17 @@ config ZX2967_WATCHDOG
>> To compile this driver as a module, choose M here: the
>> module will be called zx2967_wdt.
>>
>> +config STM32_WATCHDOG
>> + tristate "STM32 Independent WatchDoG (IWDG) support"
>> + depends on ARCH_STM32
>> + select WATCHDOG_CORE
>> + default y
>> + help
>> + Say Y here to include Watchdog timer support.
>
> ... for <pick your text>.
Ok done
>
>> +
>> + To compile this driver as a module, choose M here: the
>> + module will be called stm32_iwdg.
>> +
>> # AVR32 Architecture
>>
>> config AT32AP700X_WDT
>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
>> index a2126e2..a35e423 100644
>> --- a/drivers/watchdog/Makefile
>> +++ b/drivers/watchdog/Makefile
>> @@ -84,6 +84,7 @@ obj-$(CONFIG_ATLAS7_WATCHDOG) += atlas7_wdt.o
>> obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o
>> obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o
>> obj-$(CONFIG_ZX2967_WATCHDOG) += zx2967_wdt.o
>> +obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
>>
>> # AVR32 Architecture
>> obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
>> diff --git a/drivers/watchdog/stm32_iwdg.c
>> b/drivers/watchdog/stm32_iwdg.c
>> new file mode 100644
>> index 0000000..507dfc4
>> --- /dev/null
>> +++ b/drivers/watchdog/stm32_iwdg.c
>> @@ -0,0 +1,289 @@
>> +/*
>> + * Driver for STM32 Independent Watchdog
>> + *
>> + * Copyright (C) Yannick Fertre 2017
>> + * Author: Yannick Fertre <yannick.fertre@xxxxxx>
>> + *
>> + * This driver is based on tegra_wdt.c
>> + *
>> + * License terms: GNU General Public License (GPL), version 2
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/delay.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/io.h>
>> +#include <linux/iopoll.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/watchdog.h>
>> +
>> +/* minimum watchdog trigger timeout, in seconds */
>> +#define MIN_WDT_TIMEOUT 1
>> +
>> +/* IWDG registers */
>> +#define IWDG_KR 0x00 /* Key register */
>> +#define IWDG_PR 0x04 /* Prescaler Register */
>> +#define IWDG_RLR 0x08 /* ReLoad Register */
>> +#define IWDG_SR 0x0C /* Status Register */
>> +#define IWDG_WINR 0x10 /* Windows Register */
>> +
>> +/* IWDG_KR register bit mask */
>> +#define KR_KEY_RELOAD 0xAAAA /* reload counter enable */
>> +#define KR_KEY_ENABLE 0xCCCC /* peripheral enable */
>> +#define KR_KEY_EWA 0x5555 /* write access enable */
>> +#define KR_KEY_DWA 0x0000 /* write access disable */
>> +
>> +/* IWDG_PR register bit values */
>> +#define PR_4 0x00 /* prescaler set to 4 */
>> +#define PR_8 0x01 /* prescaler set to 8 */
>> +#define PR_16 0x02 /* prescaler set to 16 */
>> +#define PR_32 0x03 /* prescaler set to 32 */
>> +#define PR_64 0x04 /* prescaler set to 64 */
>> +#define PR_128 0x05 /* prescaler set to 128 */
>> +#define PR_256 0x06 /* prescaler set to 256 */
>> +
>> +/* IWDG_RLR register values */
>> +#define RLR_MAX 0xFFF /* max value supported by reload
>> register */
>> +
>> +/* IWDG_SR register bit mask */
>> +#define FLAG_PVU BIT(0) /* Watchdog prescaler value update */
>> +#define FLAG_RVU BIT(1) /* Watchdog counter reload value update */
>> +
>> +/* set timeout to 100000 us */
>> +#define TIMEOUT_US 100000
>> +#define SLEEP_US 1000
>> +
>> +struct stm32_iwdg {
>> + struct watchdog_device wdd;
>> + struct device *dev;
>> + void __iomem *regs;
>> + struct clk *clk;
>> + unsigned int rate;
>> +};
>> +
>> +static int heartbeat = MIN_WDT_TIMEOUT;
>> +module_param(heartbeat, int, 0x0);
>> +MODULE_PARM_DESC(heartbeat,
>> + "Watchdog heartbeats in seconds. (default = "
>> + __MODULE_STRING(WDT_HEARTBEAT) ")");
>> +
>> +static inline u32 reg_read(void __iomem *base, u32 reg)
>> +{
>> + return readl_relaxed(base + reg);
>> +}
>> +
>> +static inline void reg_write(void __iomem *base, u32 reg, u32 val)
>> +{
>> + writel_relaxed(val, base + reg);
>> +}
>> +
>> +static int stm32_iwdg_start(struct watchdog_device *wdd)
>> +{
>> + struct stm32_iwdg *wdt = watchdog_get_drvdata(wdd);
>> + u32 val = FLAG_PVU | FLAG_RVU;
>> + u32 reload;
>> + int ret;
>> +
>> + dev_dbg(wdt->dev, "%s\n", __func__);
>> +
>> + /* prescaler fixed to 256 */
>> + reload = (wdd->timeout * wdt->rate) / 256;
>> + if (reload > RLR_MAX + 1) {
>> + dev_err(wdt->dev,
>> + "Watchdog doesn't support reload value: %d\n", reload);
>> + return -EINVAL;
>> + }
>
> This should not happen if min_timeout and max_timeout are set properly.
>
Ok, I remove the test.
>> +
>> + /* enable watchdog */
>> + reg_write(wdt->regs, IWDG_KR, KR_KEY_ENABLE);
>> +
>> + /* set prescaler & reload registers */
>> + reg_write(wdt->regs, IWDG_KR, KR_KEY_EWA);
>> + reg_write(wdt->regs, IWDG_PR, PR_256); /* prescaler fix to 256 */
>> + reg_write(wdt->regs, IWDG_RLR, reload - 1);
>> +
>> + /* wait for the registers to be updated (max 100ms) */
>> + ret = readl_relaxed_poll_timeout(wdt->regs + IWDG_SR, val,
>> + !(val & (FLAG_PVU | FLAG_RVU)),
>> + SLEEP_US, TIMEOUT_US);
>> + if (ret) {
>> + dev_err(wdt->dev,
>> + "Fail to set prescaler or reload registers\n");
>> + return -EINVAL;
>
> Any reason for overriding the return value ?
>
Ok, done
>> + }
>> +
>> + /* reload watchdog */
>> + reg_write(wdt->regs, IWDG_KR, KR_KEY_RELOAD);
>> +
>> + return 0;
>> +}
>> +
>> +static int stm32_iwdg_stop(struct watchdog_device *wdd)
>> +{
>> + struct stm32_iwdg *wdt = watchdog_get_drvdata(wdd);
>> +
>> + if (watchdog_active(wdd)) {
>> + dev_err(wdt->dev,
>> + "Watchdog can't be stopped once started(no way out)\n");
>> + return -EPERM;
>
> The infrastructure takes care of this. Don't provide a stop function,
> and provide
> the maximum hardware timeout.
Ok, I remove stop function
>
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int stm32_iwdg_ping(struct watchdog_device *wdd)
>> +{
>> + struct stm32_iwdg *wdt = watchdog_get_drvdata(wdd);
>> +
>> + dev_dbg(wdt->dev, "%s\n", __func__);
>> +
>> + reg_write(wdt->regs, IWDG_KR, KR_KEY_RELOAD);
>> +
>> + return 0;
>> +}
>> +
>> +static int stm32_iwdg_set_timeout(struct watchdog_device *wdd,
>> + unsigned int timeout)
>> +{
>> + struct stm32_iwdg *wdt = watchdog_get_drvdata(wdd);
>> +
>> + dev_dbg(wdt->dev, "%s timeout: %d sec\n", __func__, timeout);
>> +
>> + wdd->timeout = timeout;
>> +
>> + if (watchdog_active(wdd))
>> + return stm32_iwdg_start(wdd);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct watchdog_info stm32_iwdg_info = {
>> + .options = WDIOF_SETTIMEOUT |
>> + WDIOF_MAGICCLOSE |
>> + WDIOF_KEEPALIVEPING,
>> + .identity = "STM32 Independent Watchdog",
>> +};
>> +
>> +static struct watchdog_ops stm32_iwdg_ops = {
>> + .owner = THIS_MODULE,
>> + .start = stm32_iwdg_start,
>> + .stop = stm32_iwdg_stop,
>> + .ping = stm32_iwdg_ping,
>> + .set_timeout = stm32_iwdg_set_timeout,
>> +};
>> +
>> +static int stm32_iwdg_probe(struct platform_device *pdev)
>> +{
>> + struct watchdog_device *wdd;
>> + struct stm32_iwdg *wdt;
>> + struct resource *res;
>> + void __iomem *regs;
>> + struct clk *clk;
>> + int max_wdt_timeout;
>> + int ret;
>> +
>> + /* This is the timer base. */
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + regs = devm_ioremap_resource(&pdev->dev, res);
>> + if (IS_ERR(regs)) {
>> + dev_err(&pdev->dev, "Could not get resource\n");
>> + return PTR_ERR(regs);
>> + }
>> +
>> + clk = devm_clk_get(&pdev->dev, NULL);
>> + if (IS_ERR(clk)) {
>> + dev_err(&pdev->dev, "Unable to get clock\n");
>> + return PTR_ERR(clk);
>> + }
>> +
>> + ret = clk_prepare_enable(clk);
>> + if (ret) {
>> + dev_err(&pdev->dev, "Unable to prepare clock %p\n", clk);
>> + return ret;
>> + }
>> +
>> + /*
>> + * Allocate our watchdog driver data, which has the
>> + * struct watchdog_device nested within it.
>> + */
>> + wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
>> + if (!wdt) {
>> + ret = -ENOMEM;
>> + goto err;
>> + }
>> +
>> + /* Initialize struct stm32_iwdg. */
>> + wdt->regs = regs;
>> + wdt->dev = &pdev->dev;
>> + wdt->clk = clk;
>> + /*
>> + * iwdg is clocked by its own dedicated low-speed clock (LSI)
>> + * at 32khz.
>> + */
>> + wdt->rate = 32 * 1024;
>
> Why not clk_get_rate() ?
Ok, done
>
>> +
>> + /* get max timeout & set heartbeat */
>> + max_wdt_timeout = ((RLR_MAX + 1) * 256) / wdt->rate;
>> + heartbeat = max_wdt_timeout;
>
> What is the value of overwriting this variable ? Why don't you just use
> max_wdt_timeout,
> and what is the point of making heartbeat configurable if you overwrite
> it anyway ?
>
> I would suggest to use watchdog_init_timeout() to set optional non-default
> timeout values, especially since this also enables getting the timeout
> value from
> devicetree.
>
Ok done
>> +
>> + /* Initialize struct watchdog_device. */
>> + wdd = &wdt->wdd;
>> + wdd->timeout = heartbeat;
>> + wdd->info = &stm32_iwdg_info;
>> + wdd->ops = &stm32_iwdg_ops;
>> + wdd->min_timeout = MIN_WDT_TIMEOUT;
>> + wdd->max_timeout = max_wdt_timeout;
>
> You might want to consider setting max_hw_heartbeat_ms instead and drop
> the stop function.
>
Ok, done
>> + watchdog_set_drvdata(wdd, wdt);
>> + watchdog_set_nowayout(wdd, true);
>> +
>> + ret = watchdog_register_device(wdd);
>> + if (ret) {
>> + dev_err(&pdev->dev,
>> + "failed to register watchdog device\n");
>> + goto err;
>> + }
>> +
>> + platform_set_drvdata(pdev, wdt);
>> +
>> + dev_info(&pdev->dev,
>> + "initialized (heartbeat = %d sec)\n", heartbeat);
>> + return 0;
>> +
>> +err:
>> + clk_disable_unprepare(clk);
>> + return ret;
>> +}
>> +
>> +static int stm32_iwdg_remove(struct platform_device *pdev)
>> +{
>> + struct stm32_iwdg *wdt = platform_get_drvdata(pdev);
>> +
>> + watchdog_unregister_device(&wdt->wdd);
>> + clk_disable_unprepare(wdt->clk);
>> +
>> + dev_info(&pdev->dev, "removed watchdog device\n");
>
> Is this message really useful ? I think it is just noise.
Ok, removed
>
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id stm32_iwdg_of_match[] = {
>> + { .compatible = "st,stm32-iwdg" },
>> + { /* end node */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, stm32_iwdg_of_match);
>> +
>> +static struct platform_driver stm32_iwdg_driver = {
>> + .probe = stm32_iwdg_probe,
>> + .remove = stm32_iwdg_remove,
>> + .driver = {
>> + .name = "iwdg",
>> + .of_match_table = stm32_iwdg_of_match,
>> + },
>> +};
>> +module_platform_driver(stm32_iwdg_driver);
>> +
>> +MODULE_AUTHOR("Yannick Fertre <yannick.fertre@xxxxxx>");
>> +MODULE_DESCRIPTION("STMicroelectronics STM32 Independent Watchdog
>> Driver");
>> +MODULE_LICENSE("GPL v2");
>>
>--
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