Hi Baoyou,
This version looks better - just a couple of comments below on things I didn't
notice before.
On Thu, Feb 02, 2017 at 05:16:35PM +0800, Baoyou Xie wrote:
> This patch adds watchdog controller driver for ZTE's zx2967 family.
>
> Signed-off-by: Baoyou Xie <baoyou....@linaro.org>
> ---
> drivers/watchdog/Kconfig | 10 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/zx2967_wdt.c | 274
> ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 285 insertions(+)
> create mode 100644 drivers/watchdog/zx2967_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index acb00b5..05093a2 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 0c3d35e..bf2d296 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..818f17e
> --- /dev/null
> +++ b/drivers/watchdog/zx2967_wdt.c
> @@ -0,0 +1,274 @@
> +/*
> + * watchdog driver for ZTE's zx2967 family
> + *
> + * Copyright (C) 2017 ZTE Ltd.
> + *
> + * Author: Baoyou Xie <baoyou....@linaro.org>
> + *
> + * License terms: GNU General Public License (GPL) version 2
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.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)
> +#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 524
> +#define ZX2967_WDT_MAX_COUNT 0xffff
> +
> +#define ZX2967_WDT_CLK_FREQ 0x8000
> +
> +#define ZX2967_WDT_FLAG_REBOOT_MON BIT(0)
> +
> +struct zx2967_wdt {
> + struct watchdog_device wdt_device;
> + void __iomem *reg_base;
> + struct clk *clock;
> +};
> +
> +static inline u32 zx2967_wdt_readl(struct zx2967_wdt *wdt, u16 reg)
> +{
> + return readl_relaxed(wdt->reg_base + reg);
> +}
> +
> +static inline void zx2967_wdt_writel(struct zx2967_wdt *wdt, u16 reg, u32
> val)
> +{
> + writel_relaxed(val | ZX2967_WDT_WRITEKEY, wdt->reg_base + reg);
I fail to understand the reason behind OR'ing values written to every register
with ZX2967_WDT_WRITEKEY (apologies if this was already discussed), especially
since 'val' is a u32.
A mask of 0x12340000 definitely looks odd to me. Something like 0x0003ffff
would have been understandable. I also worry that any value greater than
0x3ffff will be corrupted when being OR'ed with ZX2967_WDT_WRITEKEY.
> +}
> +
> +static void zx2967_wdt_refresh(struct zx2967_wdt *wdt)
> +{
> + u32 val;
> +
> + val = zx2967_wdt_readl(wdt, ZX2967_WDT_REFRESH_REG);
> + val ^= ZX2967_WDT_REFRESH_MASK;
> + zx2967_wdt_writel(wdt, ZX2967_WDT_REFRESH_REG, val);
Same thing here... Why is an XOR operation needed? Please add good
comments in the code when doing things like that. Again, apologies if you
already answered this question.
> +}
> +
> +static int
> +zx2967_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout)
> +{
> + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
> + unsigned int divisor = ZX2967_WDT_DIV_DEFAULT;
> + unsigned int count;
> +
> + count = timeout * ZX2967_WDT_CLK_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_writel(wdt, ZX2967_WDT_CFG_REG, ZX2967_WDT_CFG_DIV(divisor));
> + zx2967_wdt_writel(wdt, ZX2967_WDT_LOAD_REG, count);
> + zx2967_wdt_refresh(wdt);
> + wdd->timeout = (count * divisor) / ZX2967_WDT_CLK_FREQ;
> +
> + return 0;
> +}
> +
> +static void __zx2967_wdt_start(struct zx2967_wdt *wdt)
> +{
> + u32 val;
> +
> + val = zx2967_wdt_readl(wdt, ZX2967_WDT_START_REG);
> + val |= ZX2967_WDT_START_EN;
> + zx2967_wdt_writel(wdt, ZX2967_WDT_START_REG, val);
> +}
> +
> +static void __zx2967_wdt_stop(struct zx2967_wdt *wdt)
> +{
> + u32 val;
> +
> + val = zx2967_wdt_readl(wdt, ZX2967_WDT_START_REG);
> + val &= ~ZX2967_WDT_START_EN;
> + zx2967_wdt_writel(wdt, ZX2967_WDT_START_REG, val);
> +}
> +
> +static int zx2967_wdt_start(struct watchdog_device *wdd)
> +{
> + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
> +
> + 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,
> + .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_reset_sysctrl(struct device *dev)
> +{
> + int ret;
> + void __iomem *regmap;
> + unsigned int offset, mask, config;
> + struct of_phandle_args out_args;
> +
> + ret = of_parse_phandle_with_fixed_args(dev->of_node,
> + "zte,wdt-reset-sysctrl", 3, 0, &out_args);
> + if (ret)
> + return;
> +
> + offset = out_args.args[0];
> + config = out_args.args[1];
> + mask = out_args.args[2];
> +
> + regmap = syscon_node_to_regmap(out_args.np);
> + if (IS_ERR(regmap)) {
> + of_node_put(out_args.np);
> + return;
> + }
> +
> + regmap_update_bits(regmap, offset, mask, config);
> + of_node_put(out_args.np);
> +}
> +
> +static int zx2967_wdt_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct zx2967_wdt *wdt;
> + struct resource *base;
> + int ret;
> + struct reset_control *rstc;
> +
> + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
> + if (!wdt)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, wdt);
> +
> + 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);
> + if (IS_ERR(wdt->reg_base)) {
> + dev_err(dev, "ioremap failed\n");
> + return PTR_ERR(wdt->reg_base);
> + }
> +
> + zx2967_wdt_reset_sysctrl(dev);
> +
> + wdt->clock = devm_clk_get(dev, NULL);
> + if (IS_ERR(wdt->clock)) {
> + dev_err(dev, "failed to find watchdog clock source\n");
> + return PTR_ERR(wdt->clock);
> + }
> +
> + ret = clk_prepare_enable(wdt->clock);
> + if (ret < 0) {
> + dev_err(dev, "failed to enable clock\n");
> + return ret;
> + }
> + clk_set_rate(wdt->clock, ZX2967_WDT_CLK_FREQ);
> +
> + rstc = devm_reset_control_get(dev, NULL);
> + if (IS_ERR(rstc)) {
> + dev_err(dev, "failed to get rstc");
> + ret = PTR_ERR(rstc);
> + goto err;
> + }
> +
> + reset_control_assert(rstc);
> + reset_control_deassert(rstc);
Much better.
> +
> + watchdog_set_drvdata(&wdt->wdt_device, wdt);
> + watchdog_init_timeout(&wdt->wdt_device,
> + ZX2967_WDT_DEFAULT_TIMEOUT, dev);
> + watchdog_set_nowayout(&wdt->wdt_device, WATCHDOG_NOWAYOUT);
> +
> + ret = watchdog_register_device(&wdt->wdt_device);
> + if (ret)
> + goto err;
> +
> + dev_info(dev, "watchdog enabled (timeout=%d sec, nowayout=%d)",
> + wdt->wdt_device.timeout, WATCHDOG_NOWAYOUT);
> +
> + return 0;
> +
> +err:
> + clk_disable_unprepare(wdt->clock);
> + return ret;
> +}
> +
> +static int zx2967_wdt_remove(struct platform_device *pdev)
> +{
> + struct zx2967_wdt *wdt = platform_get_drvdata(pdev);
> +
> + watchdog_unregister_device(&wdt->wdt_device);
> + clk_disable_unprepare(wdt->clock);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id zx2967_wdt_match[] = {
> + { .compatible = "zte,zx296718-wdt", },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, zx2967_wdt_match);
> +
> +static struct platform_driver zx2967_wdt_driver = {
> + .probe = zx2967_wdt_probe,
> + .remove = zx2967_wdt_remove,
> + .driver = {
> + .name = "zx2967-wdt",
> + .of_match_table = of_match_ptr(zx2967_wdt_match),
> + },
> +};
> +module_platform_driver(zx2967_wdt_driver);
> +
> +MODULE_AUTHOR("Baoyou Xie <baoyou....@linaro.org>");
> +MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.7.4
>
