--- /dev/null
+/*
+ * Watchdog for the 7101 PMU version found in the ALi M1535 chipsets
+ *
+ * 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; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/ioport.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/pci.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+
+#define WATCHDOG_NAME "ALi_M1535"
+#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
+
+/* internal variables */
+static unsigned long ali_is_open;
+static char ali_expect_release;
+static struct pci_dev *ali_pci;
+static u32 ali_timeout_bits; /* stores the computed timeout */
+static DEFINE_SPINLOCK(ali_lock); /* Guards the hardware */
+
+/* module parameters */
+static int timeout = WATCHDOG_TIMEOUT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout,
+ "Watchdog timeout in seconds. (0 < timeout < 18000, default="
+ __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+ "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+/*
+ * ali_start - start watchdog countdown
+ *
+ * Starts the timer running providing the timer has a counter
+ * configuration set.
+ */
+
+static void ali_start(void)
+{
+ u32 val;
+
+ spin_lock(&ali_lock);
+
+ pci_read_config_dword(ali_pci, 0xCC, &val);
+ val &= ~0x3F; /* Mask count */
+ val |= (1 << 25) | ali_timeout_bits;
+ pci_write_config_dword(ali_pci, 0xCC, val);
+
+ spin_unlock(&ali_lock);
+}
+
+/*
+ * ali_stop - stop the timer countdown
+ *
+ * Stop the ALi watchdog countdown
+ */
+
+static void ali_stop(void)
+{
+ u32 val;
+
+ spin_lock(&ali_lock);
+
+ pci_read_config_dword(ali_pci, 0xCC, &val);
+ val &= ~0x3F; /* Mask count to zero (disabled) */
+ val &= ~(1 << 25); /* and for safety mask the reset enable */
+ pci_write_config_dword(ali_pci, 0xCC, val);
+
+ spin_unlock(&ali_lock);
+}
+
+/*
+ * ali_keepalive - send a keepalive to the watchdog
+ *
+ * Send a keepalive to the timer (actually we restart the timer).
+ */
+
+static void ali_keepalive(void)
+{
+ ali_start();
+}
+
+/*
+ * ali_settimer - compute the timer reload value
+ * @t: time in seconds
+ *
+ * Computes the timeout values needed
+ */
+
+static int ali_settimer(int t)
+{
+ if (t < 0)
+ return -EINVAL;
+ else if (t < 60)
+ ali_timeout_bits = t|(1 << 6);
+ else if (t < 3600)
+ ali_timeout_bits = (t / 60)|(1 << 7);
+ else if (t < 18000)
+ ali_timeout_bits = (t / 300)|(1 << 6)|(1 << 7);
+ else
+ return -EINVAL;
+
+ timeout = t;
+ return 0;
+}
+
+/*
+ * /dev/watchdog handling
+ */
+
+/*
+ * ali_write - writes to ALi watchdog
+ * @file: file from VFS
+ * @data: user address of data
+ * @len: length of data
+ * @ppos: pointer to the file offset
+ *
+ * Handle a write to the ALi watchdog. Writing to the file pings
+ * the watchdog and resets it. Writing the magic 'V' sequence allows
+ * the next close to turn off the watchdog.
+ */
+
+static ssize_t ali_write(struct file *file, const char __user *data,
+ size_t len, loff_t *ppos)
+{
+ /* See if we got the magic character 'V' and reload the timer */
+ if (len) {
+ if (!nowayout) {
+ size_t i;
+
+ /* note: just in case someone wrote the
+ magic character five months ago... */
+ ali_expect_release = 0;
+
+ /* scan to see whether or not we got
+ the magic character */
+ for (i = 0; i != len; i++) {
+ char c;
+ if (get_user(c, data + i))
+ return -EFAULT;
+ if (c == 'V')
+ ali_expect_release = 42;
+ }
+ }
+
+ /* someone wrote to us, we should reload the timer */
+ ali_start();
+ }
+ return len;
+}
+
+/*
+ * ali_ioctl - handle watchdog ioctls
+ * @file: VFS file pointer
+ * @cmd: ioctl number
+ * @arg: arguments to the ioctl
+ *
+ * Handle the watchdog ioctls supported by the ALi driver. Really
+ * we want an extension to enable irq ack monitoring and the like
+ */
+
+static long ali_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ static const struct watchdog_info ident = {
+ .options = WDIOF_KEEPALIVEPING |
+ WDIOF_SETTIMEOUT |
+ WDIOF_MAGICCLOSE,
+ .firmware_version = 0,
+ .identity = "ALi M1535 WatchDog Timer",
+ };
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(0, p);
+ case WDIOC_SETOPTIONS:
+ {
+ int new_options, retval = -EINVAL;
+
+ if (get_user(new_options, p))
+ return -EFAULT;
+ if (new_options & WDIOS_DISABLECARD) {
+ ali_stop();
+ retval = 0;
+ }
+ if (new_options & WDIOS_ENABLECARD) {
+ ali_start();
+ retval = 0;
+ }
+ return retval;
+ }
+ case WDIOC_KEEPALIVE:
+ ali_keepalive();
+ return 0;
+ case WDIOC_SETTIMEOUT:
+ {
+ int new_timeout;
+ if (get_user(new_timeout, p))
+ return -EFAULT;
+ if (ali_settimer(new_timeout))
+ return -EINVAL;
+ ali_keepalive();
+ /* Fall */
+ }
+ case WDIOC_GETTIMEOUT:
+ return put_user(timeout, p);
+ default:
+ return -ENOTTY;
+ }
+}
+
+/*
+ * ali_open - handle open of ali watchdog
+ * @inode: inode from VFS
+ * @file: file from VFS
+ *
+ * Open the ALi watchdog device. Ensure only one person opens it
+ * at a time. Also start the watchdog running.
+ */
+
+static int ali_open(struct inode *inode, struct file *file)
+{
+ /* /dev/watchdog can only be opened once */
+ if (test_and_set_bit(0, &ali_is_open))
+ return -EBUSY;
+
+ /* Activate */
+ ali_start();
+ return nonseekable_open(inode, file);
+}
+
+/*
+ * ali_release - close an ALi watchdog
+ * @inode: inode from VFS
+ * @file: file from VFS
+ *
+ * Close the ALi watchdog device. Actual shutdown of the timer
+ * only occurs if the magic sequence has been set.
+ */
+
+static int ali_release(struct inode *inode, struct file *file)
+{
+ /*
+ * Shut off the timer.
+ */
+ if (ali_expect_release == 42)
+ ali_stop();
+ else {
+ pr_crit("Unexpected close, not stopping watchdog!\n");
+ ali_keepalive();
+ }
+ clear_bit(0, &ali_is_open);
+ ali_expect_release = 0;
+ return 0;
+}
+
+/*
+ * ali_notify_sys - System down notifier
+ *
+ * Notifier for system down
+ */
+
+
+static int ali_notify_sys(struct notifier_block *this,
+ unsigned long code, void *unused)
+{
+ if (code == SYS_DOWN || code == SYS_HALT)
+ ali_stop(); /* Turn the WDT off */
+ return NOTIFY_DONE;
+}
+
+/*
+ * Data for PCI driver interface
+ *
+ * This data only exists for exporting the supported
+ * PCI ids via MODULE_DEVICE_TABLE. We do not actually
+ * register a pci_driver, because someone else might one day
+ * want to register another driver on the same PCI id.
+ */
+
+static const struct pci_device_id ali_pci_tbl[] __used = {
+ { PCI_VENDOR_ID_AL, 0x1533, PCI_ANY_ID, PCI_ANY_ID,},
+ { PCI_VENDOR_ID_AL, 0x1535, PCI_ANY_ID, PCI_ANY_ID,},
+ { 0, },
+};
+MODULE_DEVICE_TABLE(pci, ali_pci_tbl);
+
+/*
+ * ali_find_watchdog - find a 1535 and 7101
+ *
+ * Scans the PCI hardware for a 1535 series bridge and matching 7101
+ * watchdog device. This may be overtight but it is better to be safe
+ */
+
+static int __init ali_find_watchdog(void)
+{
+ struct pci_dev *pdev;
+ u32 wdog;
+
+ /* Check for a 1533/1535 series bridge */
+ pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1535, NULL);
+ if (pdev == NULL)
+ pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1533, NULL);
+ if (pdev == NULL)
+ return -ENODEV;
+ pci_dev_put(pdev);
+
+ /* Check for the a 7101 PMU */
+ pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x7101, NULL);
+ if (pdev == NULL)
+ return -ENODEV;
+
+ if (pci_enable_device(pdev)) {
+ pci_dev_put(pdev);
+ return -EIO;
+ }
+
+ ali_pci = pdev;
+
+ /*
+ * Initialize the timer bits
+ */
+ pci_read_config_dword(pdev, 0xCC, &wdog);
+
+ /* Timer bits */
+ wdog &= ~0x3F;
+ /* Issued events */
+ wdog &= ~((1 << 27)|(1 << 26)|(1 << 25)|(1 << 24));
+ /* No monitor bits */
+ wdog &= ~((1 << 16)|(1 << 13)|(1 << 12)|(1 << 11)|(1 << 10)|(1 << 9));
+
+ pci_write_config_dword(pdev, 0xCC, wdog);
+
+ return 0;
+}
+
+/*
+ * Kernel Interfaces
+ */
+
+static const struct file_operations ali_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = ali_write,
+ .unlocked_ioctl = ali_ioctl,
+ .open = ali_open,
+ .release = ali_release,
+};
+
+static struct miscdevice ali_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &ali_fops,
+};
+
+static struct notifier_block ali_notifier = {
+ .notifier_call = ali_notify_sys,
+};
+
+/*
+ * watchdog_init - module initialiser
+ *
+ * Scan for a suitable watchdog and if so initialize it. Return an error
+ * if we cannot, the error causes the module to unload
+ */
+
+static int __init watchdog_init(void)
+{
+ int ret;
+
+ /* Check whether or not the hardware watchdog is there */
+ if (ali_find_watchdog() != 0)
+ return -ENODEV;
+
+ /* Check that the timeout value is within it's range;
+ if not reset to the default */
+ if (timeout < 1 || timeout >= 18000) {
+ timeout = WATCHDOG_TIMEOUT;
+ pr_info("timeout value must be 0 < timeout < 18000, using %d\n",
+ timeout);
+ }
+
+ /* Calculate the watchdog's timeout */
+ ali_settimer(timeout);
+
+ ret = register_reboot_notifier(&ali_notifier);
+ if (ret != 0) {
+ pr_err("cannot register reboot notifier (err=%d)\n", ret);
+ goto out;
+ }
+
+ ret = misc_register(&ali_miscdev);
+ if (ret != 0) {
+ pr_err("cannot register miscdev on minor=%d (err=%d)\n",
+ WATCHDOG_MINOR, ret);
+ goto unreg_reboot;
+ }
+
+ pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
+ timeout, nowayout);
+
+out:
+ return ret;
+unreg_reboot:
+ unregister_reboot_notifier(&ali_notifier);
+ goto out;
+}
+
+/*
+ * watchdog_exit - module de-initialiser
+ *
+ * Called while unloading a successfully installed watchdog module.
+ */
+
+static void __exit watchdog_exit(void)
+{
+ /* Stop the timer before we leave */
+ ali_stop();
+
+ /* Deregister */
+ misc_deregister(&ali_miscdev);
+ unregister_reboot_notifier(&ali_notifier);
+ pci_dev_put(ali_pci);
+}
+
+module_init(watchdog_init);
+module_exit(watchdog_exit);
+
+MODULE_AUTHOR("Alan Cox");
+MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff