| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (C) 2013 Broadcom Corporation |
| * |
| */ |
| |
| #include <linux/debugfs.h> |
| #include <linux/delay.h> |
| #include <linux/err.h> |
| #include <linux/io.h> |
| #include <linux/module.h> |
| #include <linux/of_address.h> |
| #include <linux/platform_device.h> |
| #include <linux/watchdog.h> |
| |
| #define SECWDOG_CTRL_REG 0x00000000 |
| #define SECWDOG_COUNT_REG 0x00000004 |
| |
| #define SECWDOG_RESERVED_MASK 0x1dffffff |
| #define SECWDOG_WD_LOAD_FLAG 0x10000000 |
| #define SECWDOG_EN_MASK 0x08000000 |
| #define SECWDOG_SRSTEN_MASK 0x04000000 |
| #define SECWDOG_RES_MASK 0x00f00000 |
| #define SECWDOG_COUNT_MASK 0x000fffff |
| |
| #define SECWDOG_MAX_COUNT SECWDOG_COUNT_MASK |
| #define SECWDOG_CLKS_SHIFT 20 |
| #define SECWDOG_MAX_RES 15 |
| #define SECWDOG_DEFAULT_RESOLUTION 4 |
| #define SECWDOG_MAX_TRY 1000 |
| |
| #define SECS_TO_TICKS(x, w) ((x) << (w)->resolution) |
| #define TICKS_TO_SECS(x, w) ((x) >> (w)->resolution) |
| |
| #define BCM_KONA_WDT_NAME "bcm_kona_wdt" |
| |
| struct bcm_kona_wdt { |
| void __iomem *base; |
| /* |
| * One watchdog tick is 1/(2^resolution) seconds. Resolution can take |
| * the values 0-15, meaning one tick can be 1s to 30.52us. Our default |
| * resolution of 4 means one tick is 62.5ms. |
| * |
| * The watchdog counter is 20 bits. Depending on resolution, the maximum |
| * counter value of 0xfffff expires after about 12 days (resolution 0) |
| * down to only 32s (resolution 15). The default resolution of 4 gives |
| * us a maximum of about 18 hours and 12 minutes before the watchdog |
| * times out. |
| */ |
| int resolution; |
| spinlock_t lock; |
| #ifdef CONFIG_BCM_KONA_WDT_DEBUG |
| unsigned long busy_count; |
| struct dentry *debugfs; |
| #endif |
| }; |
| |
| static int secure_register_read(struct bcm_kona_wdt *wdt, uint32_t offset) |
| { |
| uint32_t val; |
| unsigned count = 0; |
| |
| /* |
| * If the WD_LOAD_FLAG is set, the watchdog counter field is being |
| * updated in hardware. Once the WD timer is updated in hardware, it |
| * gets cleared. |
| */ |
| do { |
| if (unlikely(count > 1)) |
| udelay(5); |
| val = readl_relaxed(wdt->base + offset); |
| count++; |
| } while ((val & SECWDOG_WD_LOAD_FLAG) && count < SECWDOG_MAX_TRY); |
| |
| #ifdef CONFIG_BCM_KONA_WDT_DEBUG |
| /* Remember the maximum number iterations due to WD_LOAD_FLAG */ |
| if (count > wdt->busy_count) |
| wdt->busy_count = count; |
| #endif |
| |
| /* This is the only place we return a negative value. */ |
| if (val & SECWDOG_WD_LOAD_FLAG) |
| return -ETIMEDOUT; |
| |
| /* We always mask out reserved bits. */ |
| val &= SECWDOG_RESERVED_MASK; |
| |
| return val; |
| } |
| |
| #ifdef CONFIG_BCM_KONA_WDT_DEBUG |
| |
| static int bcm_kona_show(struct seq_file *s, void *data) |
| { |
| int ctl_val, cur_val; |
| unsigned long flags; |
| struct bcm_kona_wdt *wdt = s->private; |
| |
| if (!wdt) { |
| seq_puts(s, "No device pointer\n"); |
| return 0; |
| } |
| |
| spin_lock_irqsave(&wdt->lock, flags); |
| ctl_val = secure_register_read(wdt, SECWDOG_CTRL_REG); |
| cur_val = secure_register_read(wdt, SECWDOG_COUNT_REG); |
| spin_unlock_irqrestore(&wdt->lock, flags); |
| |
| if (ctl_val < 0 || cur_val < 0) { |
| seq_puts(s, "Error accessing hardware\n"); |
| } else { |
| int ctl, cur, ctl_sec, cur_sec, res; |
| |
| ctl = ctl_val & SECWDOG_COUNT_MASK; |
| res = (ctl_val & SECWDOG_RES_MASK) >> SECWDOG_CLKS_SHIFT; |
| cur = cur_val & SECWDOG_COUNT_MASK; |
| ctl_sec = TICKS_TO_SECS(ctl, wdt); |
| cur_sec = TICKS_TO_SECS(cur, wdt); |
| seq_printf(s, |
| "Resolution: %d / %d\n" |
| "Control: %d s / %d (%#x) ticks\n" |
| "Current: %d s / %d (%#x) ticks\n" |
| "Busy count: %lu\n", |
| res, wdt->resolution, |
| ctl_sec, ctl, ctl, |
| cur_sec, cur, cur, |
| wdt->busy_count); |
| } |
| |
| return 0; |
| } |
| |
| DEFINE_SHOW_ATTRIBUTE(bcm_kona); |
| |
| static void bcm_kona_wdt_debug_init(struct platform_device *pdev) |
| { |
| struct dentry *dir; |
| struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev); |
| |
| if (!wdt) |
| return; |
| |
| wdt->debugfs = NULL; |
| |
| dir = debugfs_create_dir(BCM_KONA_WDT_NAME, NULL); |
| if (IS_ERR_OR_NULL(dir)) |
| return; |
| |
| if (debugfs_create_file("info", S_IFREG | S_IRUGO, dir, wdt, |
| &bcm_kona_fops)) |
| wdt->debugfs = dir; |
| else |
| debugfs_remove_recursive(dir); |
| } |
| |
| static void bcm_kona_wdt_debug_exit(struct platform_device *pdev) |
| { |
| struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev); |
| |
| if (wdt && wdt->debugfs) { |
| debugfs_remove_recursive(wdt->debugfs); |
| wdt->debugfs = NULL; |
| } |
| } |
| |
| #else |
| |
| static void bcm_kona_wdt_debug_init(struct platform_device *pdev) {} |
| static void bcm_kona_wdt_debug_exit(struct platform_device *pdev) {} |
| |
| #endif /* CONFIG_BCM_KONA_WDT_DEBUG */ |
| |
| static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt, |
| unsigned mask, unsigned newval) |
| { |
| int val; |
| unsigned long flags; |
| int ret = 0; |
| |
| spin_lock_irqsave(&wdt->lock, flags); |
| |
| val = secure_register_read(wdt, SECWDOG_CTRL_REG); |
| if (val < 0) { |
| ret = val; |
| } else { |
| val &= ~mask; |
| val |= newval; |
| writel_relaxed(val, wdt->base + SECWDOG_CTRL_REG); |
| } |
| |
| spin_unlock_irqrestore(&wdt->lock, flags); |
| |
| return ret; |
| } |
| |
| static int bcm_kona_wdt_set_resolution_reg(struct bcm_kona_wdt *wdt) |
| { |
| if (wdt->resolution > SECWDOG_MAX_RES) |
| return -EINVAL; |
| |
| return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_RES_MASK, |
| wdt->resolution << SECWDOG_CLKS_SHIFT); |
| } |
| |
| static int bcm_kona_wdt_set_timeout_reg(struct watchdog_device *wdog, |
| unsigned watchdog_flags) |
| { |
| struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog); |
| |
| return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_COUNT_MASK, |
| SECS_TO_TICKS(wdog->timeout, wdt) | |
| watchdog_flags); |
| } |
| |
| static int bcm_kona_wdt_set_timeout(struct watchdog_device *wdog, |
| unsigned int t) |
| { |
| wdog->timeout = t; |
| return 0; |
| } |
| |
| static unsigned int bcm_kona_wdt_get_timeleft(struct watchdog_device *wdog) |
| { |
| struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog); |
| int val; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&wdt->lock, flags); |
| val = secure_register_read(wdt, SECWDOG_COUNT_REG); |
| spin_unlock_irqrestore(&wdt->lock, flags); |
| |
| if (val < 0) |
| return val; |
| |
| return TICKS_TO_SECS(val & SECWDOG_COUNT_MASK, wdt); |
| } |
| |
| static int bcm_kona_wdt_start(struct watchdog_device *wdog) |
| { |
| return bcm_kona_wdt_set_timeout_reg(wdog, |
| SECWDOG_EN_MASK | SECWDOG_SRSTEN_MASK); |
| } |
| |
| static int bcm_kona_wdt_stop(struct watchdog_device *wdog) |
| { |
| struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog); |
| |
| return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_EN_MASK | |
| SECWDOG_SRSTEN_MASK, 0); |
| } |
| |
| static const struct watchdog_ops bcm_kona_wdt_ops = { |
| .owner = THIS_MODULE, |
| .start = bcm_kona_wdt_start, |
| .stop = bcm_kona_wdt_stop, |
| .set_timeout = bcm_kona_wdt_set_timeout, |
| .get_timeleft = bcm_kona_wdt_get_timeleft, |
| }; |
| |
| static const struct watchdog_info bcm_kona_wdt_info = { |
| .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | |
| WDIOF_KEEPALIVEPING, |
| .identity = "Broadcom Kona Watchdog Timer", |
| }; |
| |
| static struct watchdog_device bcm_kona_wdt_wdd = { |
| .info = &bcm_kona_wdt_info, |
| .ops = &bcm_kona_wdt_ops, |
| .min_timeout = 1, |
| .max_timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION, |
| .timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION, |
| }; |
| |
| static int bcm_kona_wdt_probe(struct platform_device *pdev) |
| { |
| struct device *dev = &pdev->dev; |
| struct bcm_kona_wdt *wdt; |
| int ret; |
| |
| wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); |
| if (!wdt) |
| return -ENOMEM; |
| |
| spin_lock_init(&wdt->lock); |
| |
| wdt->base = devm_platform_ioremap_resource(pdev, 0); |
| if (IS_ERR(wdt->base)) |
| return -ENODEV; |
| |
| wdt->resolution = SECWDOG_DEFAULT_RESOLUTION; |
| ret = bcm_kona_wdt_set_resolution_reg(wdt); |
| if (ret) { |
| dev_err(dev, "Failed to set resolution (error: %d)", ret); |
| return ret; |
| } |
| |
| platform_set_drvdata(pdev, wdt); |
| watchdog_set_drvdata(&bcm_kona_wdt_wdd, wdt); |
| bcm_kona_wdt_wdd.parent = dev; |
| |
| ret = bcm_kona_wdt_set_timeout_reg(&bcm_kona_wdt_wdd, 0); |
| if (ret) { |
| dev_err(dev, "Failed set watchdog timeout"); |
| return ret; |
| } |
| |
| watchdog_stop_on_reboot(&bcm_kona_wdt_wdd); |
| watchdog_stop_on_unregister(&bcm_kona_wdt_wdd); |
| ret = devm_watchdog_register_device(dev, &bcm_kona_wdt_wdd); |
| if (ret) { |
| dev_err(dev, "Failed to register watchdog device"); |
| return ret; |
| } |
| |
| bcm_kona_wdt_debug_init(pdev); |
| dev_dbg(dev, "Broadcom Kona Watchdog Timer"); |
| |
| return 0; |
| } |
| |
| static int bcm_kona_wdt_remove(struct platform_device *pdev) |
| { |
| bcm_kona_wdt_debug_exit(pdev); |
| dev_dbg(&pdev->dev, "Watchdog driver disabled"); |
| |
| return 0; |
| } |
| |
| static const struct of_device_id bcm_kona_wdt_of_match[] = { |
| { .compatible = "brcm,kona-wdt", }, |
| {}, |
| }; |
| MODULE_DEVICE_TABLE(of, bcm_kona_wdt_of_match); |
| |
| static struct platform_driver bcm_kona_wdt_driver = { |
| .driver = { |
| .name = BCM_KONA_WDT_NAME, |
| .of_match_table = bcm_kona_wdt_of_match, |
| }, |
| .probe = bcm_kona_wdt_probe, |
| .remove = bcm_kona_wdt_remove, |
| }; |
| |
| module_platform_driver(bcm_kona_wdt_driver); |
| |
| MODULE_ALIAS("platform:" BCM_KONA_WDT_NAME); |
| MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>"); |
| MODULE_DESCRIPTION("Broadcom Kona Watchdog Driver"); |
| MODULE_LICENSE("GPL v2"); |