diff options
Diffstat (limited to 'drivers/watchdog/imx7ulp_wdt.c')
| -rw-r--r-- | drivers/watchdog/imx7ulp_wdt.c | 420 |
1 files changed, 420 insertions, 0 deletions
diff --git a/drivers/watchdog/imx7ulp_wdt.c b/drivers/watchdog/imx7ulp_wdt.c new file mode 100644 index 0000000000..c703586c6e --- /dev/null +++ b/drivers/watchdog/imx7ulp_wdt.c @@ -0,0 +1,420 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2019 NXP. + */ + +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/reboot.h> +#include <linux/watchdog.h> + +#define WDOG_CS 0x0 +#define WDOG_CS_FLG BIT(14) +#define WDOG_CS_CMD32EN BIT(13) +#define WDOG_CS_PRES BIT(12) +#define WDOG_CS_ULK BIT(11) +#define WDOG_CS_RCS BIT(10) +#define LPO_CLK 0x1 +#define LPO_CLK_SHIFT 8 +#define WDOG_CS_CLK (LPO_CLK << LPO_CLK_SHIFT) +#define WDOG_CS_EN BIT(7) +#define WDOG_CS_UPDATE BIT(5) +#define WDOG_CS_WAIT BIT(1) +#define WDOG_CS_STOP BIT(0) + +#define WDOG_CNT 0x4 +#define WDOG_TOVAL 0x8 + +#define REFRESH_SEQ0 0xA602 +#define REFRESH_SEQ1 0xB480 +#define REFRESH ((REFRESH_SEQ1 << 16) | REFRESH_SEQ0) + +#define UNLOCK_SEQ0 0xC520 +#define UNLOCK_SEQ1 0xD928 +#define UNLOCK ((UNLOCK_SEQ1 << 16) | UNLOCK_SEQ0) + +#define DEFAULT_TIMEOUT 60 +#define MAX_TIMEOUT 128 +#define WDOG_CLOCK_RATE 1000 +#define WDOG_ULK_WAIT_TIMEOUT 1000 +#define WDOG_RCS_WAIT_TIMEOUT 10000 +#define WDOG_RCS_POST_WAIT 3000 + +#define RETRY_MAX 5 + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0000); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +struct imx_wdt_hw_feature { + bool prescaler_enable; + u32 wdog_clock_rate; +}; + +struct imx7ulp_wdt_device { + struct watchdog_device wdd; + void __iomem *base; + struct clk *clk; + bool post_rcs_wait; + const struct imx_wdt_hw_feature *hw; +}; + +static int imx7ulp_wdt_wait_ulk(void __iomem *base) +{ + u32 val = readl(base + WDOG_CS); + + if (!(val & WDOG_CS_ULK) && + readl_poll_timeout_atomic(base + WDOG_CS, val, + val & WDOG_CS_ULK, 0, + WDOG_ULK_WAIT_TIMEOUT)) + return -ETIMEDOUT; + + return 0; +} + +static int imx7ulp_wdt_wait_rcs(struct imx7ulp_wdt_device *wdt) +{ + int ret = 0; + u32 val = readl(wdt->base + WDOG_CS); + u64 timeout = (val & WDOG_CS_PRES) ? + WDOG_RCS_WAIT_TIMEOUT * 256 : WDOG_RCS_WAIT_TIMEOUT; + unsigned long wait_min = (val & WDOG_CS_PRES) ? + WDOG_RCS_POST_WAIT * 256 : WDOG_RCS_POST_WAIT; + + if (!(val & WDOG_CS_RCS) && + readl_poll_timeout(wdt->base + WDOG_CS, val, val & WDOG_CS_RCS, 100, + timeout)) + ret = -ETIMEDOUT; + + /* Wait 2.5 clocks after RCS done */ + if (wdt->post_rcs_wait) + usleep_range(wait_min, wait_min + 2000); + + return ret; +} + +static int _imx7ulp_wdt_enable(struct imx7ulp_wdt_device *wdt, bool enable) +{ + u32 val = readl(wdt->base + WDOG_CS); + int ret; + + local_irq_disable(); + writel(UNLOCK, wdt->base + WDOG_CNT); + ret = imx7ulp_wdt_wait_ulk(wdt->base); + if (ret) + goto enable_out; + if (enable) + writel(val | WDOG_CS_EN, wdt->base + WDOG_CS); + else + writel(val & ~WDOG_CS_EN, wdt->base + WDOG_CS); + + local_irq_enable(); + ret = imx7ulp_wdt_wait_rcs(wdt); + + return ret; + +enable_out: + local_irq_enable(); + return ret; +} + +static int imx7ulp_wdt_enable(struct watchdog_device *wdog, bool enable) +{ + struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog); + int ret; + u32 val; + u32 loop = RETRY_MAX; + + do { + ret = _imx7ulp_wdt_enable(wdt, enable); + val = readl(wdt->base + WDOG_CS); + } while (--loop > 0 && ((!!(val & WDOG_CS_EN)) != enable || ret)); + + if (loop == 0) + return -EBUSY; + + return ret; +} + +static int imx7ulp_wdt_ping(struct watchdog_device *wdog) +{ + struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog); + + writel(REFRESH, wdt->base + WDOG_CNT); + + return 0; +} + +static int imx7ulp_wdt_start(struct watchdog_device *wdog) +{ + return imx7ulp_wdt_enable(wdog, true); +} + +static int imx7ulp_wdt_stop(struct watchdog_device *wdog) +{ + return imx7ulp_wdt_enable(wdog, false); +} + +static int _imx7ulp_wdt_set_timeout(struct imx7ulp_wdt_device *wdt, + unsigned int toval) +{ + int ret; + + local_irq_disable(); + writel(UNLOCK, wdt->base + WDOG_CNT); + ret = imx7ulp_wdt_wait_ulk(wdt->base); + if (ret) + goto timeout_out; + writel(toval, wdt->base + WDOG_TOVAL); + local_irq_enable(); + ret = imx7ulp_wdt_wait_rcs(wdt); + return ret; + +timeout_out: + local_irq_enable(); + return ret; +} + +static int imx7ulp_wdt_set_timeout(struct watchdog_device *wdog, + unsigned int timeout) +{ + struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog); + u32 toval = wdt->hw->wdog_clock_rate * timeout; + u32 val; + int ret; + u32 loop = RETRY_MAX; + + do { + ret = _imx7ulp_wdt_set_timeout(wdt, toval); + val = readl(wdt->base + WDOG_TOVAL); + } while (--loop > 0 && (val != toval || ret)); + + if (loop == 0) + return -EBUSY; + + wdog->timeout = timeout; + return ret; +} + +static int imx7ulp_wdt_restart(struct watchdog_device *wdog, + unsigned long action, void *data) +{ + struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog); + int ret; + + ret = imx7ulp_wdt_enable(wdog, true); + if (ret) + return ret; + + ret = imx7ulp_wdt_set_timeout(&wdt->wdd, 1); + if (ret) + return ret; + + /* wait for wdog to fire */ + while (true) + ; + + return NOTIFY_DONE; +} + +static const struct watchdog_ops imx7ulp_wdt_ops = { + .owner = THIS_MODULE, + .start = imx7ulp_wdt_start, + .stop = imx7ulp_wdt_stop, + .ping = imx7ulp_wdt_ping, + .set_timeout = imx7ulp_wdt_set_timeout, + .restart = imx7ulp_wdt_restart, +}; + +static const struct watchdog_info imx7ulp_wdt_info = { + .identity = "i.MX7ULP watchdog timer", + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | + WDIOF_MAGICCLOSE, +}; + +static int _imx7ulp_wdt_init(struct imx7ulp_wdt_device *wdt, unsigned int timeout, unsigned int cs) +{ + u32 val; + int ret; + + local_irq_disable(); + + val = readl(wdt->base + WDOG_CS); + if (val & WDOG_CS_CMD32EN) { + writel(UNLOCK, wdt->base + WDOG_CNT); + } else { + mb(); + /* unlock the wdog for reconfiguration */ + writel_relaxed(UNLOCK_SEQ0, wdt->base + WDOG_CNT); + writel_relaxed(UNLOCK_SEQ1, wdt->base + WDOG_CNT); + mb(); + } + + ret = imx7ulp_wdt_wait_ulk(wdt->base); + if (ret) + goto init_out; + + /* set an initial timeout value in TOVAL */ + writel(timeout, wdt->base + WDOG_TOVAL); + writel(cs, wdt->base + WDOG_CS); + local_irq_enable(); + ret = imx7ulp_wdt_wait_rcs(wdt); + + return ret; + +init_out: + local_irq_enable(); + return ret; +} + +static int imx7ulp_wdt_init(struct imx7ulp_wdt_device *wdt, unsigned int timeout) +{ + /* enable 32bit command sequence and reconfigure */ + u32 val = WDOG_CS_CMD32EN | WDOG_CS_CLK | WDOG_CS_UPDATE | + WDOG_CS_WAIT | WDOG_CS_STOP; + u32 cs, toval; + int ret; + u32 loop = RETRY_MAX; + + if (wdt->hw->prescaler_enable) + val |= WDOG_CS_PRES; + + do { + ret = _imx7ulp_wdt_init(wdt, timeout, val); + toval = readl(wdt->base + WDOG_TOVAL); + cs = readl(wdt->base + WDOG_CS); + cs &= ~(WDOG_CS_FLG | WDOG_CS_ULK | WDOG_CS_RCS); + } while (--loop > 0 && (cs != val || toval != timeout || ret)); + + if (loop == 0) + return -EBUSY; + + return ret; +} + +static int imx7ulp_wdt_probe(struct platform_device *pdev) +{ + struct imx7ulp_wdt_device *imx7ulp_wdt; + struct device *dev = &pdev->dev; + struct watchdog_device *wdog; + int ret; + + imx7ulp_wdt = devm_kzalloc(dev, sizeof(*imx7ulp_wdt), GFP_KERNEL); + if (!imx7ulp_wdt) + return -ENOMEM; + + platform_set_drvdata(pdev, imx7ulp_wdt); + + imx7ulp_wdt->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(imx7ulp_wdt->base)) + return PTR_ERR(imx7ulp_wdt->base); + + imx7ulp_wdt->clk = devm_clk_get_enabled(dev, NULL); + if (IS_ERR(imx7ulp_wdt->clk)) { + dev_err(dev, "Failed to get watchdog clock\n"); + return PTR_ERR(imx7ulp_wdt->clk); + } + + imx7ulp_wdt->post_rcs_wait = true; + if (of_device_is_compatible(dev->of_node, + "fsl,imx8ulp-wdt")) { + dev_info(dev, "imx8ulp wdt probe\n"); + imx7ulp_wdt->post_rcs_wait = false; + } else { + dev_info(dev, "imx7ulp wdt probe\n"); + } + + wdog = &imx7ulp_wdt->wdd; + wdog->info = &imx7ulp_wdt_info; + wdog->ops = &imx7ulp_wdt_ops; + wdog->min_timeout = 1; + wdog->max_timeout = MAX_TIMEOUT; + wdog->parent = dev; + wdog->timeout = DEFAULT_TIMEOUT; + + watchdog_init_timeout(wdog, 0, dev); + watchdog_stop_on_reboot(wdog); + watchdog_stop_on_unregister(wdog); + watchdog_set_drvdata(wdog, imx7ulp_wdt); + + imx7ulp_wdt->hw = of_device_get_match_data(dev); + ret = imx7ulp_wdt_init(imx7ulp_wdt, wdog->timeout * imx7ulp_wdt->hw->wdog_clock_rate); + if (ret) + return ret; + + return devm_watchdog_register_device(dev, wdog); +} + +static int __maybe_unused imx7ulp_wdt_suspend_noirq(struct device *dev) +{ + struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev); + + if (watchdog_active(&imx7ulp_wdt->wdd)) + imx7ulp_wdt_stop(&imx7ulp_wdt->wdd); + + clk_disable_unprepare(imx7ulp_wdt->clk); + + return 0; +} + +static int __maybe_unused imx7ulp_wdt_resume_noirq(struct device *dev) +{ + struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev); + u32 timeout = imx7ulp_wdt->wdd.timeout * imx7ulp_wdt->hw->wdog_clock_rate; + int ret; + + ret = clk_prepare_enable(imx7ulp_wdt->clk); + if (ret) + return ret; + + if (watchdog_active(&imx7ulp_wdt->wdd)) { + imx7ulp_wdt_init(imx7ulp_wdt, timeout); + imx7ulp_wdt_start(&imx7ulp_wdt->wdd); + imx7ulp_wdt_ping(&imx7ulp_wdt->wdd); + } + + return 0; +} + +static const struct dev_pm_ops imx7ulp_wdt_pm_ops = { + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx7ulp_wdt_suspend_noirq, + imx7ulp_wdt_resume_noirq) +}; + +static const struct imx_wdt_hw_feature imx7ulp_wdt_hw = { + .prescaler_enable = false, + .wdog_clock_rate = 1000, +}; + +static const struct imx_wdt_hw_feature imx93_wdt_hw = { + .prescaler_enable = true, + .wdog_clock_rate = 125, +}; + +static const struct of_device_id imx7ulp_wdt_dt_ids[] = { + { .compatible = "fsl,imx8ulp-wdt", .data = &imx7ulp_wdt_hw, }, + { .compatible = "fsl,imx7ulp-wdt", .data = &imx7ulp_wdt_hw, }, + { .compatible = "fsl,imx93-wdt", .data = &imx93_wdt_hw, }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, imx7ulp_wdt_dt_ids); + +static struct platform_driver imx7ulp_wdt_driver = { + .probe = imx7ulp_wdt_probe, + .driver = { + .name = "imx7ulp-wdt", + .pm = &imx7ulp_wdt_pm_ops, + .of_match_table = imx7ulp_wdt_dt_ids, + }, +}; +module_platform_driver(imx7ulp_wdt_driver); + +MODULE_AUTHOR("Anson Huang <Anson.Huang@nxp.com>"); +MODULE_DESCRIPTION("Freescale i.MX7ULP watchdog driver"); +MODULE_LICENSE("GPL v2"); |