Re: [PATCH v1 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family

From: Shawn Guo
Date: Tue Jan 17 2017 - 03:56:50 EST

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In reply to: Jun Nie: "Re: [PATCH v1 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family"
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On Mon, Jan 16, 2017 at 12:19:55PM +0800, Baoyou Xie wrote:
> This patch adds watchdog controller driver for ZTE's zx2967 family.
>
> Signed-off-by: Baoyou Xie <baoyou.xie@xxxxxxxxxx>
> ---
> drivers/watchdog/Kconfig | 10 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/zx2967_wdt.c | 405 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 416 insertions(+)
> create mode 100644 drivers/watchdog/zx2967_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 3eb58cb..79027da 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -714,6 +714,16 @@ config ASPEED_WATCHDOG
> To compile this driver as a module, choose M here: the
> module will be called aspeed_wdt.
>
> +config ZX2967_WATCHDOG
> + tristate "ZTE zx2967 SoCs watchdog support"
> + depends on ARCH_ZX
> + select WATCHDOG_CORE
> + help
> + Say Y here to include support for the watchdog timer
> + in ZTE zx2967 SoCs.
> + To compile this driver as a module, choose M here: the
> + module will be called zx2967_wdt.
> +
> # AVR32 Architecture
>
> config AT32AP700X_WDT
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index caa9f4a..ea08925 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -82,6 +82,7 @@ obj-$(CONFIG_BCM7038_WDT) += bcm7038_wdt.o
> obj-$(CONFIG_ATLAS7_WATCHDOG) += atlas7_wdt.o
> obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o
> obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o
> +obj-$(CONFIG_ZX2967_WATCHDOG) += zx2967_wdt.o
>
> # AVR32 Architecture
> obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
> diff --git a/drivers/watchdog/zx2967_wdt.c b/drivers/watchdog/zx2967_wdt.c
> new file mode 100644
> index 0000000..8791dd2
> --- /dev/null
> +++ b/drivers/watchdog/zx2967_wdt.c
> @@ -0,0 +1,405 @@
> +/*
> + * watchdog driver for ZTE's zx2967 family
> + *
> + * Copyright (C) 2017 ZTE Ltd.
> + *
> + * Author: Baoyou Xie <baoyou.xie@xxxxxxxxxx>
> + *
> + * License terms: GNU General Public License (GPL) version 2
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/reboot.h>
> +#include <linux/reset.h>
> +#include <linux/watchdog.h>
> +
> +#define ZX2967_WDT_CFG_REG 0x4
> +#define ZX2967_WDT_LOAD_REG 0x8
> +#define ZX2967_WDT_REFRESH_REG 0x18
> +#define ZX2967_WDT_START_REG 0x1c
> +
> +#define ZX2967_WDT_REFRESH_MASK 0x3f
> +
> +#define ZX2967_WDT_CFG_DIV(n) ((((n)&0xff) - 1) << 8)

Please have a space before and after '&' operator.

> +#define ZX2967_WDT_START_EN 0x1
> +
> +#define ZX2967_WDT_WRITEKEY 0x12340000
> +
> +#define ZX2967_WDT_DIV_DEFAULT 16
> +#define ZX2967_WDT_DEFAULT_TIMEOUT 32
> +#define ZX2967_WDT_MIN_TIMEOUT 1
> +#define ZX2967_WDT_MAX_TIMEOUT 500
> +#define ZX2967_WDT_MAX_COUNT 0xffff
> +
> +#define ZX2967_WDT_FLAG_REBOOT_MON (1 << 0)
> +
> +#define ZX2967_RESET_MASK_REG 0xb0
> +
> +#define zx2967_wdt_write_reg(v, r) \
> + writel((v) | ZX2967_WDT_WRITEKEY, r)
> +#define zx2967_wdt_read_reg(r) readl(r)

I think inline functions are better than macros in this case.

> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +static unsigned int timeout = ZX2967_WDT_DEFAULT_TIMEOUT;

The variable name is too generic. For example, the same name is used in
functions like __zx2967_wdt_set_timeout().

> +
> +struct zx2967_wdt {
> + struct device *dev;
> + struct clk *clock;
> + void __iomem *reg_base;
> + unsigned int conf;
> + unsigned int load;
> + unsigned int flags;
> + spinlock_t lock;
> + struct watchdog_device wdt_device;
> + struct notifier_block restart_handler;
> + struct notifier_block reboot_handler;
> +};
> +
> +static void zx2967_wdt_refresh(struct zx2967_wdt *wdt)
> +{
> + unsigned int val;

u32 for 32-bit register access is more readable.

> +
> + spin_lock(&wdt->lock);
> +
> + val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_REFRESH_REG);
> + val ^= ZX2967_WDT_REFRESH_MASK;
> + zx2967_wdt_write_reg(val, wdt->reg_base + ZX2967_WDT_REFRESH_REG);
> +
> + spin_unlock(&wdt->lock);
> +}
> +
> +static void __zx2967_wdt_stop(struct zx2967_wdt *wdt)
> +{
> + unsigned int val;
> +
> + spin_lock(&wdt->lock);
> +
> + val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_START_REG);
> + val &= ~(ZX2967_WDT_START_EN);

The parentheses is not needed.

> + zx2967_wdt_write_reg(val, wdt->reg_base + ZX2967_WDT_START_REG);
> +
> + spin_unlock(&wdt->lock);
> +}
> +
> +static void __zx2967_wdt_start(struct zx2967_wdt *wdt)
> +{
> + unsigned int val;
> +
> + spin_lock(&wdt->lock);
> +
> + val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_START_REG);
> + val |= ZX2967_WDT_START_EN;
> + zx2967_wdt_write_reg(val, wdt->reg_base + ZX2967_WDT_START_REG);
> +
> + spin_unlock(&wdt->lock);
> +}
> +
> +static unsigned int
> +__zx2967_wdt_set_timeout(struct zx2967_wdt *wdt, unsigned int timeout)
> +{
> + unsigned int freq = clk_get_rate(wdt->clock);
> + unsigned int divisor = ZX2967_WDT_DIV_DEFAULT, count;

Unless the variables are closely related, it's more conventional to have
each variable on a new line.

> +
> + count = timeout * freq;
> + if (count > divisor * ZX2967_WDT_MAX_COUNT)
> + divisor = DIV_ROUND_UP(count, ZX2967_WDT_MAX_COUNT);
> + count = DIV_ROUND_UP(count, divisor);
> + zx2967_wdt_write_reg(ZX2967_WDT_CFG_DIV(divisor),
> + wdt->reg_base + ZX2967_WDT_CFG_REG);
> + zx2967_wdt_write_reg(count, wdt->reg_base + ZX2967_WDT_LOAD_REG);
> + zx2967_wdt_refresh(wdt);
> +
> + wdt->load = count;
> + dev_info(wdt->dev, "count=%d, timeout=%d, divisor=%d\n",
> + count, timeout, divisor);

Noisy. Maybe dev_dbg().

> +
> + return (count * divisor) / freq;
> +}
> +
> +static int zx2967_wdt_set_timeout(struct watchdog_device *wdd,
> + unsigned int timeout)
> +{
> + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
> +
> + if (watchdog_timeout_invalid(&wdt->wdt_device, timeout)) {
> + dev_err(wdt->dev, "timeout %d is invalid\n", timeout);
> +

Drop the newline.

> + return -EINVAL;
> + }
> +
> + wdd->timeout = __zx2967_wdt_set_timeout(wdt, timeout);
> +
> + return 0;
> +}
> +
> +static int zx2967_wdt_start(struct watchdog_device *wdd)
> +{
> + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
> +
> + __zx2967_wdt_stop(wdt);
> + zx2967_wdt_set_timeout(wdd, wdd->timeout);
> + __zx2967_wdt_start(wdt);
> +
> + return 0;
> +}
> +
> +static int zx2967_wdt_stop(struct watchdog_device *wdd)
> +{
> + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
> +
> + __zx2967_wdt_stop(wdt);
> +
> + return 0;
> +}
> +
> +static int zx2967_wdt_keepalive(struct watchdog_device *wdd)
> +{
> + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
> +
> + zx2967_wdt_refresh(wdt);
> +
> + return 0;
> +}
> +
> +#define ZX2967_WDT_OPTIONS \
> + (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
> +static const struct watchdog_info zx2967_wdt_ident = {
> + .options = ZX2967_WDT_OPTIONS,
> + .firmware_version = 0,
> + .identity = "zx2967 watchdog",
> +};
> +
> +static struct watchdog_ops zx2967_wdt_ops = {
> + .owner = THIS_MODULE,
> + .start = zx2967_wdt_start,
> + .stop = zx2967_wdt_stop,
> + .ping = zx2967_wdt_keepalive,
> + .set_timeout = zx2967_wdt_set_timeout,
> +};
> +
> +static void zx2967_wdt_fix_sysdown(struct zx2967_wdt *wdt)
> +{
> + __zx2967_wdt_stop(wdt);
> + __zx2967_wdt_set_timeout(wdt, 15);
> + __zx2967_wdt_start(wdt);
> +}
> +
> +static int zx2967_wdt_notify_sys(struct notifier_block *this,
> + unsigned long code, void *unused)
> +{
> + struct zx2967_wdt *wdt = container_of(this, struct zx2967_wdt,
> + reboot_handler);
> +
> + wdt->flags |= ZX2967_WDT_FLAG_REBOOT_MON;
> + switch (code) {
> + case SYS_HALT:
> + case SYS_POWER_OFF:
> + case SYS_RESTART:
> + zx2967_wdt_fix_sysdown(wdt);
> + break;
> + default:
> + break;
> + }
> +
> + return 0;
> +}
> +
> +static int zx2967_wdt_restart(struct notifier_block *this,
> + unsigned long mode, void *cmd)
> +{
> + struct zx2967_wdt *wdt;
> +
> + wdt = container_of(this, struct zx2967_wdt, restart_handler);
> +
> + zx2967_wdt_stop(&wdt->wdt_device);
> +
> + zx2967_wdt_write_reg(0x80, wdt->reg_base + ZX2967_WDT_LOAD_REG);
> + zx2967_wdt_refresh(wdt);
> + zx2967_wdt_write_reg(ZX2967_WDT_START_EN,
> + wdt->reg_base + ZX2967_WDT_START_REG);
> +
> + zx2967_wdt_start(&wdt->wdt_device);
> + /* wait for reset*/
> + mdelay(500);
> +
> + return NOTIFY_DONE;
> +}
> +
> +static void zx2967_reset_mask_config(struct device *dev)
> +{
> + struct device_node *np = NULL;
> + void __iomem *reg;
> + unsigned int val, mask, config, size;
> + const unsigned int *prop;
> +
> + prop = of_get_property(dev->of_node, "reset-mask-config", &size);
> + if (size < (sizeof(*prop) * 2)) {
> + dev_err(dev, "bad data for reset-mask-config");
> + return;
> + }
> + config = be32_to_cpup(prop++);
> + mask = be32_to_cpup(prop);
> + np = of_find_compatible_node(NULL, NULL, "zte,aon-sysctrl");
> + if (!np) {
> + dev_err(dev, "Cannot found pcu device node\n");
> + return;
> + }
> + reg = of_iomap(np, 0) + ZX2967_RESET_MASK_REG;
> + of_node_put(np);

We should use syscon interface to access sysctrl block.

> +
> + val = readl(reg);
> + val &= ~mask;
> + val |= config;
> + writel(val, reg);
> +}
> +
> +static int zx2967_wdt_probe(struct platform_device *pdev)
> +{
> + struct device *dev;
> + struct zx2967_wdt *wdt;
> + struct resource *base;
> + int err, ret = 0;
> + unsigned int rate, val;
> +
> + struct reset_control *rstc;
> +
> + dev = &pdev->dev;
> +
> + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
> + if (!wdt) {
> + ret = -ENOMEM;
> + goto out;
> + }

return -ENOMEM;

> +
> + platform_set_drvdata(pdev, wdt);
> +
> + wdt->dev = dev;
> + spin_lock_init(&wdt->lock);
> +
> + wdt->wdt_device.info = &zx2967_wdt_ident;
> + wdt->wdt_device.ops = &zx2967_wdt_ops;
> + wdt->wdt_device.timeout = ZX2967_WDT_DEFAULT_TIMEOUT;
> + wdt->wdt_device.max_timeout = ZX2967_WDT_MAX_TIMEOUT;
> + wdt->wdt_device.min_timeout = ZX2967_WDT_MIN_TIMEOUT;
> + wdt->wdt_device.parent = &pdev->dev;
> +
> + base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + wdt->reg_base = devm_ioremap_resource(dev, base);

It should be error checked.

> +
> + if (of_find_property(dev->of_node, "reset-mask-config", NULL))
> + zx2967_reset_mask_config(dev);
> +
> + wdt->reboot_handler.notifier_call = zx2967_wdt_notify_sys;
> + ret = register_reboot_notifier(&wdt->reboot_handler);
> + wdt->clock = devm_clk_get(dev, "wdtclk");
> + if (IS_ERR(wdt->clock)) {
> + dev_err(dev, "failed to find watchdog clock source\n");
> + ret = PTR_ERR(wdt->clock);
> + goto out;
> + }
> + ret = clk_prepare_enable(wdt->clock);
> + if (ret < 0) {
> + dev_err(dev, "failed to enable clock\n");
> + goto out;
> + }
> +
> + rate = clk_get_rate(wdt->clock);
> + if (rate == 24000000)
> + ret = clk_set_rate(wdt->clock, 32768);
> + rate = clk_get_rate(wdt->clock);
> +
> + rstc = devm_reset_control_get(dev, "wdtrst");
> + if (!rstc) {
> + dev_info(dev, "rstc get failed");
> + } else {
> + reset_control_assert(rstc);
> + mdelay(10);
> + reset_control_deassert(rstc);
> + }
> +
> + watchdog_set_drvdata(&wdt->wdt_device, wdt);
> +
> + watchdog_init_timeout(&wdt->wdt_device, timeout, &pdev->dev);
> + watchdog_set_nowayout(&wdt->wdt_device, nowayout);
> +
> + zx2967_wdt_stop(&wdt->wdt_device);
> +
> + err = watchdog_register_device(&wdt->wdt_device);
> + if (unlikely(err)) {
> + ret = err;
> + goto fail_register;
> + }
> +
> + wdt->restart_handler.notifier_call = zx2967_wdt_restart;
> + wdt->restart_handler.priority = 128;
> + ret = register_restart_handler(&wdt->restart_handler);
> + if (ret) {
> + pr_err("cannot register restart handler, %d\n", ret);

dev_err()

> + goto fail_restart;
> + }
> +
> + val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_START_REG);
> + dev_info(&pdev->dev, "watchdog enabled (timeout=%d sec, nowayout=%d)",
> + wdt->wdt_device.timeout, nowayout);
> +
> + return 0;
> +
> +fail_restart:
> + watchdog_unregister_device(&wdt->wdt_device);
> +fail_register:
> + clk_disable_unprepare(wdt->clock);
> +out:
> + return ret;
> +}
> +
> +static int zx2967_wdt_remove(struct platform_device *pdev)
> +{
> + struct zx2967_wdt *wdt = platform_get_drvdata(pdev);
> +
> + unregister_restart_handler(&wdt->restart_handler);
> + watchdog_unregister_device(&wdt->wdt_device);
> + clk_disable_unprepare(wdt->clock);
> +
> + return 0;
> +}
> +
> +static void zx2967_wdt_shutdown(struct platform_device *pdev)
> +{
> + struct zx2967_wdt *wdt = platform_get_drvdata(pdev);
> +
> + if (!(wdt->flags & ZX2967_WDT_FLAG_REBOOT_MON))
> + zx2967_wdt_stop(&wdt->wdt_device);
> +}
> +
> +static const struct of_device_id zx2967_wdt_match[] = {
> + { .compatible = "zte,zx296718-wdt", },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, zx2967_wdt_match);
> +
> +static const struct platform_device_id zx2967_wdt_ids[] = {
> + { .name = "zx2967-wdt", },
> + {}
> +};
> +MODULE_DEVICE_TABLE(platform, zx2967_wdt_ids);

This is not needed, as we do not support platform probe but only DT on
ZTE platforms.

Shawn

> +
> +static struct platform_driver zx2967_wdt_driver = {
> + .probe = zx2967_wdt_probe,
> + .remove = zx2967_wdt_remove,
> + .shutdown = zx2967_wdt_shutdown,
> + .id_table = zx2967_wdt_ids,
> + .driver = {
> + .name = "zx2967-wdt",
> + .of_match_table = of_match_ptr(zx2967_wdt_match),
> + },
> +};
> +module_platform_driver(zx2967_wdt_driver);
> +
> +MODULE_AUTHOR("Baoyou Xie <baoyou.xie@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
> +MODULE_LICENSE("GPL");
> --
> 2.7.4
>

Next message: Thomas Gleixner: "Re: [PATCH] clocksource: exynos_mct: clear irq at stop local mct to fix suspend"
Previous message: Joseph Qi: "Re: [PATCH v3 1/2] ocfs2/dlmglue: prepare tracking logic to avoid recursive cluster lock"
In reply to: Jun Nie: "Re: [PATCH v1 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family"
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