--- /dev/null
+/*
+ * Copyright (C) 2013 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#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 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 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;
+
+ 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;
+ }
+
+ spin_lock_init(&wdt->lock);
+ platform_set_drvdata(pdev, wdt);
+ watchdog_set_drvdata(&bcm_kona_wdt_wdd, wdt);
+
+ 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");
Code Review / kvmfornfv.git / blobdiff