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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
commit | 76cb841cb886eef6b3bee341a2266c76578724ad (patch) | |
tree | f5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /drivers/watchdog/bcm_kona_wdt.c | |
parent | Initial commit. (diff) | |
download | linux-76cb841cb886eef6b3bee341a2266c76578724ad.tar.xz linux-76cb841cb886eef6b3bee341a2266c76578724ad.zip |
Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/watchdog/bcm_kona_wdt.c')
-rw-r--r-- | drivers/watchdog/bcm_kona_wdt.c | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/drivers/watchdog/bcm_kona_wdt.c b/drivers/watchdog/bcm_kona_wdt.c new file mode 100644 index 000000000..1462be9e6 --- /dev/null +++ b/drivers/watchdog/bcm_kona_wdt.c @@ -0,0 +1,367 @@ +// 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_wdt_dbg_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; +} + +static int bcm_kona_dbg_open(struct inode *inode, struct file *file) +{ + return single_open(file, bcm_kona_wdt_dbg_show, inode->i_private); +} + +static const struct file_operations bcm_kona_dbg_operations = { + .open = bcm_kona_dbg_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +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_dbg_operations)) + 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 void bcm_kona_wdt_shutdown(struct platform_device *pdev) +{ + bcm_kona_wdt_stop(&bcm_kona_wdt_wdd); +} + +static int bcm_kona_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct bcm_kona_wdt *wdt; + struct resource *res; + int ret; + + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); + if (!wdt) + return -ENOMEM; + + spin_lock_init(&wdt->lock); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + wdt->base = devm_ioremap_resource(dev, res); + 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 = &pdev->dev; + + ret = bcm_kona_wdt_set_timeout_reg(&bcm_kona_wdt_wdd, 0); + if (ret) { + dev_err(dev, "Failed set watchdog timeout"); + return ret; + } + + ret = watchdog_register_device(&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); + bcm_kona_wdt_shutdown(pdev); + watchdog_unregister_device(&bcm_kona_wdt_wdd); + 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, + .shutdown = bcm_kona_wdt_shutdown, +}; + +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"); |