[WATCHDOG] U300 COH 901 327 watchdog driver
This patch adds support for the U300 COH 901 327 watchdog for the
U300 platform recently added to RMK:s ARM tree.
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/watchdog/coh901327_wdt.c b/drivers/watchdog/coh901327_wdt.c
new file mode 100644
index 0000000..fecb307
--- /dev/null
+++ b/drivers/watchdog/coh901327_wdt.c
@@ -0,0 +1,537 @@
+/*
+ * coh901327_wdt.c
+ *
+ * Copyright (C) 2008-2009 ST-Ericsson AB
+ * License terms: GNU General Public License (GPL) version 2
+ * Watchdog driver for the ST-Ericsson AB COH 901 327 IP core
+ * Author: Linus Walleij <linus.walleij@stericsson.com>
+ */
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/interrupt.h>
+#include <linux/pm.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/bitops.h>
+#include <linux/uaccess.h>
+#include <linux/clk.h>
+
+#define DRV_NAME "WDOG COH 901 327"
+
+/*
+ * COH 901 327 register definitions
+ */
+
+/* WDOG_FEED Register 32bit (-/W) */
+#define U300_WDOG_FR 0x00
+#define U300_WDOG_FR_FEED_RESTART_TIMER 0xFEEDU
+/* WDOG_TIMEOUT Register 32bit (R/W) */
+#define U300_WDOG_TR 0x04
+#define U300_WDOG_TR_TIMEOUT_MASK 0x7FFFU
+/* WDOG_DISABLE1 Register 32bit (-/W) */
+#define U300_WDOG_D1R 0x08
+#define U300_WDOG_D1R_DISABLE1_DISABLE_TIMER 0x2BADU
+/* WDOG_DISABLE2 Register 32bit (R/W) */
+#define U300_WDOG_D2R 0x0C
+#define U300_WDOG_D2R_DISABLE2_DISABLE_TIMER 0xCAFEU
+#define U300_WDOG_D2R_DISABLE_STATUS_DISABLED 0xDABEU
+#define U300_WDOG_D2R_DISABLE_STATUS_ENABLED 0x0000U
+/* WDOG_STATUS Register 32bit (R/W) */
+#define U300_WDOG_SR 0x10
+#define U300_WDOG_SR_STATUS_TIMED_OUT 0xCFE8U
+#define U300_WDOG_SR_STATUS_NORMAL 0x0000U
+#define U300_WDOG_SR_RESET_STATUS_RESET 0xE8B4U
+/* WDOG_COUNT Register 32bit (R/-) */
+#define U300_WDOG_CR 0x14
+#define U300_WDOG_CR_VALID_IND 0x8000U
+#define U300_WDOG_CR_VALID_STABLE 0x0000U
+#define U300_WDOG_CR_COUNT_VALUE_MASK 0x7FFFU
+/* WDOG_JTAGOVR Register 32bit (R/W) */
+#define U300_WDOG_JOR 0x18
+#define U300_WDOG_JOR_JTAG_MODE_IND 0x0002U
+#define U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE 0x0001U
+/* WDOG_RESTART Register 32bit (-/W) */
+#define U300_WDOG_RR 0x1C
+#define U300_WDOG_RR_RESTART_VALUE_RESUME 0xACEDU
+/* WDOG_IRQ_EVENT Register 32bit (R/W) */
+#define U300_WDOG_IER 0x20
+#define U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND 0x0001U
+#define U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE 0x0001U
+/* WDOG_IRQ_MASK Register 32bit (R/W) */
+#define U300_WDOG_IMR 0x24
+#define U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE 0x0001U
+/* WDOG_IRQ_FORCE Register 32bit (R/W) */
+#define U300_WDOG_IFR 0x28
+#define U300_WDOG_IFR_WILL_BARK_IRQ_FORCE_ENABLE 0x0001U
+
+/* Default timeout in seconds = 1 minute */
+static int margin = 60;
+static resource_size_t phybase;
+static resource_size_t physize;
+static int irq;
+static void __iomem *virtbase;
+static unsigned long coh901327_users;
+static unsigned long boot_status;
+static u16 wdogenablestore;
+static u16 irqmaskstore;
+static struct device *parent;
+
+/*
+ * The watchdog block is of course always clocked, the
+ * clk_enable()/clk_disable() calls are mainly for performing reference
+ * counting higher up in the clock hierarchy.
+ */
+static struct clk *clk;
+
+/*
+ * Enabling and disabling functions.
+ */
+static void coh901327_enable(u16 timeout)
+{
+ u16 val;
+
+ clk_enable(clk);
+ /* Restart timer if it is disabled */
+ val = readw(virtbase + U300_WDOG_D2R);
+ if (val == U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
+ writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
+ virtbase + U300_WDOG_RR);
+ /* Acknowledge any pending interrupt so it doesn't just fire off */
+ writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
+ virtbase + U300_WDOG_IER);
+ /* Enable the watchdog interrupt */
+ writew(U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE, virtbase + U300_WDOG_IMR);
+ /* Activate the watchdog timer */
+ writew(timeout, virtbase + U300_WDOG_TR);
+ /* Start the watchdog timer */
+ writew(U300_WDOG_FR_FEED_RESTART_TIMER, virtbase + U300_WDOG_FR);
+ /*
+ * Extra read so that this change propagate in the watchdog.
+ */
+ (void) readw(virtbase + U300_WDOG_CR);
+ val = readw(virtbase + U300_WDOG_D2R);
+ clk_disable(clk);
+ if (val != U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
+ dev_err(parent,
+ "%s(): watchdog not enabled! D2R value %04x\n",
+ __func__, val);
+}
+
+static void coh901327_disable(void)
+{
+ u16 val;
+
+ clk_enable(clk);
+ /* Disable the watchdog interrupt if it is active */
+ writew(0x0000U, virtbase + U300_WDOG_IMR);
+ /* If the watchdog is currently enabled, attempt to disable it */
+ val = readw(virtbase + U300_WDOG_D2R);
+ if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED) {
+ writew(U300_WDOG_D1R_DISABLE1_DISABLE_TIMER,
+ virtbase + U300_WDOG_D1R);
+ writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
+ virtbase + U300_WDOG_D2R);
+ /* Write this twice (else problems occur) */
+ writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
+ virtbase + U300_WDOG_D2R);
+ }
+ val = readw(virtbase + U300_WDOG_D2R);
+ clk_disable(clk);
+ if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
+ dev_err(parent,
+ "%s(): watchdog not disabled! D2R value %04x\n",
+ __func__, val);
+}
+
+static void coh901327_start(void)
+{
+ coh901327_enable(margin * 100);
+}
+
+static void coh901327_keepalive(void)
+{
+ clk_enable(clk);
+ /* Feed the watchdog */
+ writew(U300_WDOG_FR_FEED_RESTART_TIMER,
+ virtbase + U300_WDOG_FR);
+ clk_disable(clk);
+}
+
+static int coh901327_settimeout(int time)
+{
+ /*
+ * Max margin is 327 since the 10ms
+ * timeout register is max
+ * 0x7FFF = 327670ms ~= 327s.
+ */
+ if (time <= 0 || time > 327)
+ return -EINVAL;
+
+ margin = time;
+ clk_enable(clk);
+ /* Set new timeout value */
+ writew(margin * 100, virtbase + U300_WDOG_TR);
+ /* Feed the dog */
+ writew(U300_WDOG_FR_FEED_RESTART_TIMER,
+ virtbase + U300_WDOG_FR);
+ clk_disable(clk);
+ return 0;
+}
+
+/*
+ * This interrupt occurs 10 ms before the watchdog WILL bark.
+ */
+static irqreturn_t coh901327_interrupt(int irq, void *data)
+{
+ u16 val;
+
+ /*
+ * Ack IRQ? If this occurs we're FUBAR anyway, so
+ * just acknowledge, disable the interrupt and await the imminent end.
+ * If you at some point need a host of callbacks to be called
+ * when the system is about to watchdog-reset, add them here!
+ *
+ * NOTE: on future versions of this IP-block, it will be possible
+ * to prevent a watchdog reset by feeding the watchdog at this
+ * point.
+ */
+ clk_enable(clk);
+ val = readw(virtbase + U300_WDOG_IER);
+ if (val == U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND)
+ writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
+ virtbase + U300_WDOG_IER);
+ writew(0x0000U, virtbase + U300_WDOG_IMR);
+ clk_disable(clk);
+ dev_crit(parent, "watchdog is barking!\n");
+ return IRQ_HANDLED;
+}
+
+/*
+ * Allow only one user (daemon) to open the watchdog
+ */
+static int coh901327_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(1, &coh901327_users))
+ return -EBUSY;
+ coh901327_start();
+ return nonseekable_open(inode, file);
+}
+
+static int coh901327_release(struct inode *inode, struct file *file)
+{
+ clear_bit(1, &coh901327_users);
+ coh901327_disable();
+ return 0;
+}
+
+static ssize_t coh901327_write(struct file *file, const char __user *data,
+ size_t len, loff_t *ppos)
+{
+ if (len)
+ coh901327_keepalive();
+ return len;
+}
+
+static long coh901327_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ int ret = -ENOTTY;
+ u16 val;
+ int time;
+ int new_options;
+ union {
+ struct watchdog_info __user *ident;
+ int __user *i;
+ } uarg;
+ static struct watchdog_info ident = {
+ .options = WDIOF_CARDRESET |
+ WDIOF_SETTIMEOUT |
+ WDIOF_KEEPALIVEPING,
+ .identity = "COH 901 327 Watchdog",
+ .firmware_version = 1,
+ };
+ uarg.i = (int __user *)arg;
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ ret = copy_to_user(uarg.ident, &ident,
+ sizeof(ident)) ? -EFAULT : 0;
+ break;
+
+ case WDIOC_GETSTATUS:
+ ret = put_user(0, uarg.i);
+ break;
+
+ case WDIOC_GETBOOTSTATUS:
+ ret = put_user(boot_status, uarg.i);
+ break;
+
+ case WDIOC_SETOPTIONS:
+ ret = get_user(new_options, uarg.i);
+ if (ret)
+ break;
+ if (new_options & WDIOS_DISABLECARD)
+ coh901327_disable();
+ if (new_options & WDIOS_ENABLECARD)
+ coh901327_start();
+ ret = 0;
+ break;
+
+ case WDIOC_KEEPALIVE:
+ coh901327_keepalive();
+ ret = 0;
+ break;
+
+ case WDIOC_SETTIMEOUT:
+ ret = get_user(time, uarg.i);
+ if (ret)
+ break;
+
+ ret = coh901327_settimeout(time);
+ if (ret)
+ break;
+ /* Then fall through to return set value */
+
+ case WDIOC_GETTIMEOUT:
+ ret = put_user(margin, uarg.i);
+ break;
+
+ case WDIOC_GETTIMELEFT:
+ clk_enable(clk);
+ /* Read repeatedly until the value is stable! */
+ val = readw(virtbase + U300_WDOG_CR);
+ while (val & U300_WDOG_CR_VALID_IND)
+ val = readw(virtbase + U300_WDOG_CR);
+ val &= U300_WDOG_CR_COUNT_VALUE_MASK;
+ clk_disable(clk);
+ if (val != 0)
+ val /= 100;
+ ret = put_user(val, uarg.i);
+ break;
+ }
+ return ret;
+}
+
+static const struct file_operations coh901327_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = coh901327_write,
+ .unlocked_ioctl = coh901327_ioctl,
+ .open = coh901327_open,
+ .release = coh901327_release,
+};
+
+static struct miscdevice coh901327_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &coh901327_fops,
+};
+
+static int __exit coh901327_remove(struct platform_device *pdev)
+{
+ misc_deregister(&coh901327_miscdev);
+ coh901327_disable();
+ free_irq(irq, pdev);
+ clk_put(clk);
+ iounmap(virtbase);
+ release_mem_region(phybase, physize);
+ return 0;
+}
+
+
+static int __init coh901327_probe(struct platform_device *pdev)
+{
+ int ret;
+ u16 val;
+ struct resource *res;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENOENT;
+
+ parent = &pdev->dev;
+ physize = resource_size(res);
+ phybase = res->start;
+
+ if (request_mem_region(phybase, physize, DRV_NAME) == NULL) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ virtbase = ioremap(phybase, physize);
+ if (!virtbase) {
+ ret = -ENOMEM;
+ goto out_no_remap;
+ }
+
+ clk = clk_get(&pdev->dev, NULL);
+ if (IS_ERR(clk)) {
+ ret = PTR_ERR(clk);
+ dev_err(&pdev->dev, "could not get clock\n");
+ goto out_no_clk;
+ }
+ ret = clk_enable(clk);
+ if (ret) {
+ dev_err(&pdev->dev, "could not enable clock\n");
+ goto out_no_clk_enable;
+ }
+
+ val = readw(virtbase + U300_WDOG_SR);
+ switch (val) {
+ case U300_WDOG_SR_STATUS_TIMED_OUT:
+ dev_info(&pdev->dev,
+ "watchdog timed out since last chip reset!\n");
+ boot_status = WDIOF_CARDRESET;
+ /* Status will be cleared below */
+ break;
+ case U300_WDOG_SR_STATUS_NORMAL:
+ dev_info(&pdev->dev,
+ "in normal status, no timeouts have occurred.\n");
+ break;
+ default:
+ dev_info(&pdev->dev,
+ "contains an illegal status code (%08x)\n", val);
+ break;
+ }
+
+ val = readw(virtbase + U300_WDOG_D2R);
+ switch (val) {
+ case U300_WDOG_D2R_DISABLE_STATUS_DISABLED:
+ dev_info(&pdev->dev, "currently disabled.\n");
+ break;
+ case U300_WDOG_D2R_DISABLE_STATUS_ENABLED:
+ dev_info(&pdev->dev,
+ "currently enabled! (disabling it now)\n");
+ coh901327_disable();
+ break;
+ default:
+ dev_err(&pdev->dev,
+ "contains an illegal enable/disable code (%08x)\n",
+ val);
+ break;
+ }
+
+ /* Reset the watchdog */
+ writew(U300_WDOG_SR_RESET_STATUS_RESET, virtbase + U300_WDOG_SR);
+
+ irq = platform_get_irq(pdev, 0);
+ if (request_irq(irq, coh901327_interrupt, IRQF_DISABLED,
+ DRV_NAME " Bark", pdev)) {
+ ret = -EIO;
+ goto out_no_irq;
+ }
+
+ clk_disable(clk);
+
+ ret = misc_register(&coh901327_miscdev);
+ if (ret == 0)
+ dev_info(&pdev->dev,
+ "initialized. timer margin=%d sec\n", margin);
+ else
+ goto out_no_wdog;
+
+ return 0;
+
+out_no_wdog:
+ free_irq(irq, pdev);
+out_no_irq:
+ clk_disable(clk);
+out_no_clk_enable:
+ clk_put(clk);
+out_no_clk:
+ iounmap(virtbase);
+out_no_remap:
+ release_mem_region(phybase, SZ_4K);
+out:
+ return ret;
+}
+
+#ifdef CONFIG_PM
+static int coh901327_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ irqmaskstore = readw(virtbase + U300_WDOG_IMR) & 0x0001U;
+ wdogenablestore = readw(virtbase + U300_WDOG_D2R);
+ /* If watchdog is on, disable it here and now */
+ if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
+ coh901327_disable();
+ return 0;
+}
+
+static int coh901327_resume(struct platform_device *pdev)
+{
+ /* Restore the watchdog interrupt */
+ writew(irqmaskstore, virtbase + U300_WDOG_IMR);
+ if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED) {
+ /* Restart the watchdog timer */
+ writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
+ virtbase + U300_WDOG_RR);
+ writew(U300_WDOG_FR_FEED_RESTART_TIMER,
+ virtbase + U300_WDOG_FR);
+ }
+ return 0;
+}
+#else
+#define coh901327_suspend NULL
+#define coh901327_resume NULL
+#endif
+
+/*
+ * Mistreating the watchdog is the only way to perform a software reset of the
+ * system on EMP platforms. So we implement this and export a symbol for it.
+ */
+void coh901327_watchdog_reset(void)
+{
+ /* Enable even if on JTAG too */
+ writew(U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE,
+ virtbase + U300_WDOG_JOR);
+ /*
+ * Timeout = 5s, we have to wait for the watchdog reset to
+ * actually take place: the watchdog will be reloaded with the
+ * default value immediately, so we HAVE to reboot and get back
+ * into the kernel in 30s, or the device will reboot again!
+ * The boot loader will typically deactivate the watchdog, so we
+ * need time enough for the boot loader to get to the point of
+ * deactivating the watchdog before it is shut down by it.
+ *
+ * NOTE: on future versions of the watchdog, this restriction is
+ * gone: the watchdog will be reloaded with a defaul value (1 min)
+ * instead of last value, and you can conveniently set the watchdog
+ * timeout to 10ms (value = 1) without any problems.
+ */
+ coh901327_enable(500);
+ /* Return and await doom */
+}
+
+static struct platform_driver coh901327_driver = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "coh901327_wdog",
+ },
+ .remove = __exit_p(coh901327_remove),
+ .suspend = coh901327_suspend,
+ .resume = coh901327_resume,
+};
+
+static int __init coh901327_init(void)
+{
+ return platform_driver_probe(&coh901327_driver, coh901327_probe);
+}
+module_init(coh901327_init);
+
+static void __exit coh901327_exit(void)
+{
+ platform_driver_unregister(&coh901327_driver);
+}
+module_exit(coh901327_exit);
+
+MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
+MODULE_DESCRIPTION("COH 901 327 Watchdog");
+
+module_param(margin, int, 0);
+MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);