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