| /* |
| * 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/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; |
| |
| 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 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(struct watchdog_device *wdd, unsigned long action, |
| void *data) |
| { |
| struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd); |
| |
| asm9260_wdt_sys_reset(priv); |
| |
| return 0; |
| } |
| |
| static const struct watchdog_info asm9260_wdt_ident = { |
| .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
| | WDIOF_MAGICCLOSE, |
| .identity = "Alphascale asm9260 Watchdog", |
| }; |
| |
| static const 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, |
| .restart = asm9260_restart, |
| }; |
| |
| 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; |
| static 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); |
| |
| priv->rst = devm_reset_control_get_exclusive(&pdev->dev, "wdt_rst"); |
| if (IS_ERR(priv->rst)) |
| return PTR_ERR(priv->rst); |
| |
| ret = asm9260_wdt_get_dt_clks(priv); |
| if (ret) |
| return ret; |
| |
| 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"); |
| } |
| |
| watchdog_set_restart_priority(wdd, 128); |
| |
| ret = watchdog_register_device(wdd); |
| if (ret) |
| goto clk_off; |
| |
| platform_set_drvdata(pdev, priv); |
| |
| 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); |
| |
| 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", |
| .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"); |