diff options
Diffstat (limited to 'drivers/watchdog/asm9260_wdt.c')
| -rw-r--r-- | drivers/watchdog/asm9260_wdt.c | 403 |
1 files changed, 403 insertions, 0 deletions
diff --git a/drivers/watchdog/asm9260_wdt.c b/drivers/watchdog/asm9260_wdt.c new file mode 100644 index 000000000..c9686b2fd --- /dev/null +++ b/drivers/watchdog/asm9260_wdt.c @@ -0,0 +1,403 @@ +/* + * Watchdog driver for Alphascale ASM9260. + * + * Copyright (c) 2014 Oleksij Rempel <linux@rempel-privat.de> + * + * Licensed under GPLv2 or later. + */ + +#include <linux/bitops.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/reboot.h> +#include <linux/reset.h> +#include <linux/watchdog.h> + +#define CLOCK_FREQ 1000000 + +/* Watchdog Mode register */ +#define HW_WDMOD 0x00 +/* Wake interrupt. Set by HW, can't be cleared. */ +#define BM_MOD_WDINT BIT(3) +/* This bit set if timeout reached. Cleared by SW. */ +#define BM_MOD_WDTOF BIT(2) +/* HW Reset on timeout */ +#define BM_MOD_WDRESET BIT(1) +/* WD enable */ +#define BM_MOD_WDEN BIT(0) + +/* + * Watchdog Timer Constant register + * Minimal value is 0xff, the meaning of this value + * depends on used clock: T = WDCLK * (0xff + 1) * 4 + */ +#define HW_WDTC 0x04 +#define BM_WDTC_MAX(freq) (0x7fffffff / (freq)) + +/* Watchdog Feed register */ +#define HW_WDFEED 0x08 + +/* Watchdog Timer Value register */ +#define HW_WDTV 0x0c + +#define ASM9260_WDT_DEFAULT_TIMEOUT 30 + +enum asm9260_wdt_mode { + HW_RESET, + SW_RESET, + DEBUG, +}; + +struct asm9260_wdt_priv { + struct device *dev; + struct watchdog_device wdd; + struct clk *clk; + struct clk *clk_ahb; + struct reset_control *rst; + struct notifier_block restart_handler; + + void __iomem *iobase; + int irq; + unsigned long wdt_freq; + enum asm9260_wdt_mode mode; +}; + +static int asm9260_wdt_feed(struct watchdog_device *wdd) +{ + struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd); + + iowrite32(0xaa, priv->iobase + HW_WDFEED); + iowrite32(0x55, priv->iobase + HW_WDFEED); + + return 0; +} + +static unsigned int asm9260_wdt_gettimeleft(struct watchdog_device *wdd) +{ + struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd); + u32 counter; + + counter = ioread32(priv->iobase + HW_WDTV); + + return DIV_ROUND_CLOSEST(counter, priv->wdt_freq); +} + +static int asm9260_wdt_updatetimeout(struct watchdog_device *wdd) +{ + struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd); + u32 counter; + + counter = wdd->timeout * priv->wdt_freq; + + iowrite32(counter, priv->iobase + HW_WDTC); + + return 0; +} + +static int asm9260_wdt_enable(struct watchdog_device *wdd) +{ + struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd); + u32 mode = 0; + + if (priv->mode == HW_RESET) + mode = BM_MOD_WDRESET; + + iowrite32(BM_MOD_WDEN | mode, priv->iobase + HW_WDMOD); + + asm9260_wdt_updatetimeout(wdd); + + asm9260_wdt_feed(wdd); + + return 0; +} + +static int asm9260_wdt_disable(struct watchdog_device *wdd) +{ + struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd); + + /* The only way to disable WD is to reset it. */ + reset_control_assert(priv->rst); + reset_control_deassert(priv->rst); + + return 0; +} + +static int asm9260_wdt_settimeout(struct watchdog_device *wdd, unsigned int to) +{ + wdd->timeout = to; + asm9260_wdt_updatetimeout(wdd); + + return 0; +} + +static void asm9260_wdt_sys_reset(struct asm9260_wdt_priv *priv) +{ + /* init WD if it was not started */ + + iowrite32(BM_MOD_WDEN | BM_MOD_WDRESET, priv->iobase + HW_WDMOD); + + iowrite32(0xff, priv->iobase + HW_WDTC); + /* first pass correct sequence */ + asm9260_wdt_feed(&priv->wdd); + /* + * Then write wrong pattern to the feed to trigger reset + * ASAP. + */ + iowrite32(0xff, priv->iobase + HW_WDFEED); + + mdelay(1000); +} + +static irqreturn_t asm9260_wdt_irq(int irq, void *devid) +{ + struct asm9260_wdt_priv *priv = devid; + u32 stat; + + stat = ioread32(priv->iobase + HW_WDMOD); + if (!(stat & BM_MOD_WDINT)) + return IRQ_NONE; + + if (priv->mode == DEBUG) { + dev_info(priv->dev, "Watchdog Timeout. Do nothing.\n"); + } else { + dev_info(priv->dev, "Watchdog Timeout. Doing SW Reset.\n"); + asm9260_wdt_sys_reset(priv); + } + + return IRQ_HANDLED; +} + +static int asm9260_restart_handler(struct notifier_block *this, + unsigned long mode, void *cmd) +{ + struct asm9260_wdt_priv *priv = + container_of(this, struct asm9260_wdt_priv, restart_handler); + + asm9260_wdt_sys_reset(priv); + + return NOTIFY_DONE; +} + +static const struct watchdog_info asm9260_wdt_ident = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING + | WDIOF_MAGICCLOSE, + .identity = "Alphascale asm9260 Watchdog", +}; + +static struct watchdog_ops asm9260_wdt_ops = { + .owner = THIS_MODULE, + .start = asm9260_wdt_enable, + .stop = asm9260_wdt_disable, + .get_timeleft = asm9260_wdt_gettimeleft, + .ping = asm9260_wdt_feed, + .set_timeout = asm9260_wdt_settimeout, +}; + +static int asm9260_wdt_get_dt_clks(struct asm9260_wdt_priv *priv) +{ + int err; + unsigned long clk; + + priv->clk = devm_clk_get(priv->dev, "mod"); + if (IS_ERR(priv->clk)) { + dev_err(priv->dev, "Failed to get \"mod\" clk\n"); + return PTR_ERR(priv->clk); + } + + /* configure AHB clock */ + priv->clk_ahb = devm_clk_get(priv->dev, "ahb"); + if (IS_ERR(priv->clk_ahb)) { + dev_err(priv->dev, "Failed to get \"ahb\" clk\n"); + return PTR_ERR(priv->clk_ahb); + } + + err = clk_prepare_enable(priv->clk_ahb); + if (err) { + dev_err(priv->dev, "Failed to enable ahb_clk!\n"); + return err; + } + + err = clk_set_rate(priv->clk, CLOCK_FREQ); + if (err) { + clk_disable_unprepare(priv->clk_ahb); + dev_err(priv->dev, "Failed to set rate!\n"); + return err; + } + + err = clk_prepare_enable(priv->clk); + if (err) { + clk_disable_unprepare(priv->clk_ahb); + dev_err(priv->dev, "Failed to enable clk!\n"); + return err; + } + + /* wdt has internal divider */ + clk = clk_get_rate(priv->clk); + if (!clk) { + clk_disable_unprepare(priv->clk); + clk_disable_unprepare(priv->clk_ahb); + dev_err(priv->dev, "Failed, clk is 0!\n"); + return -EINVAL; + } + + priv->wdt_freq = clk / 2; + + return 0; +} + +static void asm9260_wdt_get_dt_mode(struct asm9260_wdt_priv *priv) +{ + const char *tmp; + int ret; + + /* default mode */ + priv->mode = HW_RESET; + + ret = of_property_read_string(priv->dev->of_node, + "alphascale,mode", &tmp); + if (ret < 0) + return; + + if (!strcmp(tmp, "hw")) + priv->mode = HW_RESET; + else if (!strcmp(tmp, "sw")) + priv->mode = SW_RESET; + else if (!strcmp(tmp, "debug")) + priv->mode = DEBUG; + else + dev_warn(priv->dev, "unknown reset-type: %s. Using default \"hw\" mode.", + tmp); +} + +static int asm9260_wdt_probe(struct platform_device *pdev) +{ + struct asm9260_wdt_priv *priv; + struct watchdog_device *wdd; + struct resource *res; + int ret; + const char * const mode_name[] = { "hw", "sw", "debug", }; + + priv = devm_kzalloc(&pdev->dev, sizeof(struct asm9260_wdt_priv), + GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->dev = &pdev->dev; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + priv->iobase = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(priv->iobase)) + return PTR_ERR(priv->iobase); + + ret = asm9260_wdt_get_dt_clks(priv); + if (ret) + return ret; + + priv->rst = devm_reset_control_get(&pdev->dev, "wdt_rst"); + if (IS_ERR(priv->rst)) + return PTR_ERR(priv->rst); + + wdd = &priv->wdd; + wdd->info = &asm9260_wdt_ident; + wdd->ops = &asm9260_wdt_ops; + wdd->min_timeout = 1; + wdd->max_timeout = BM_WDTC_MAX(priv->wdt_freq); + wdd->parent = &pdev->dev; + + watchdog_set_drvdata(wdd, priv); + + /* + * If 'timeout-sec' unspecified in devicetree, assume a 30 second + * default, unless the max timeout is less than 30 seconds, then use + * the max instead. + */ + wdd->timeout = ASM9260_WDT_DEFAULT_TIMEOUT; + watchdog_init_timeout(wdd, 0, &pdev->dev); + + asm9260_wdt_get_dt_mode(priv); + + if (priv->mode != HW_RESET) + priv->irq = platform_get_irq(pdev, 0); + + if (priv->irq > 0) { + /* + * Not all supported platforms specify an interrupt for the + * watchdog, so let's make it optional. + */ + ret = devm_request_irq(&pdev->dev, priv->irq, + asm9260_wdt_irq, 0, pdev->name, priv); + if (ret < 0) + dev_warn(&pdev->dev, "failed to request IRQ\n"); + } + + ret = watchdog_register_device(wdd); + if (ret) + goto clk_off; + + platform_set_drvdata(pdev, priv); + + priv->restart_handler.notifier_call = asm9260_restart_handler; + priv->restart_handler.priority = 128; + ret = register_restart_handler(&priv->restart_handler); + if (ret) + dev_warn(&pdev->dev, "cannot register restart handler\n"); + + dev_info(&pdev->dev, "Watchdog enabled (timeout: %d sec, mode: %s)\n", + wdd->timeout, mode_name[priv->mode]); + return 0; + +clk_off: + clk_disable_unprepare(priv->clk); + clk_disable_unprepare(priv->clk_ahb); + return ret; +} + +static void asm9260_wdt_shutdown(struct platform_device *pdev) +{ + struct asm9260_wdt_priv *priv = platform_get_drvdata(pdev); + + asm9260_wdt_disable(&priv->wdd); +} + +static int asm9260_wdt_remove(struct platform_device *pdev) +{ + struct asm9260_wdt_priv *priv = platform_get_drvdata(pdev); + + asm9260_wdt_disable(&priv->wdd); + + unregister_restart_handler(&priv->restart_handler); + + watchdog_unregister_device(&priv->wdd); + + clk_disable_unprepare(priv->clk); + clk_disable_unprepare(priv->clk_ahb); + + return 0; +} + +static const struct of_device_id asm9260_wdt_of_match[] = { + { .compatible = "alphascale,asm9260-wdt"}, + {}, +}; +MODULE_DEVICE_TABLE(of, asm9260_wdt_of_match); + +static struct platform_driver asm9260_wdt_driver = { + .driver = { + .name = "asm9260-wdt", + .owner = THIS_MODULE, + .of_match_table = asm9260_wdt_of_match, + }, + .probe = asm9260_wdt_probe, + .remove = asm9260_wdt_remove, + .shutdown = asm9260_wdt_shutdown, +}; +module_platform_driver(asm9260_wdt_driver); + +MODULE_DESCRIPTION("asm9260 WatchDog Timer Driver"); +MODULE_AUTHOR("Oleksij Rempel <linux@rempel-privat.de>"); +MODULE_LICENSE("GPL"); |