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![Gustavo A. R. Silva](/assets/img/avatar_default.png)
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20200707171121.GA13472@embeddedor Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
451 lines
9.7 KiB
C
451 lines
9.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Watchdog for the 7101 PMU version found in the ALi M1535 chipsets
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/ioport.h>
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#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/pci.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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#define WATCHDOG_NAME "ALi_M1535"
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#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
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/* internal variables */
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static unsigned long ali_is_open;
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static char ali_expect_release;
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static struct pci_dev *ali_pci;
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static u32 ali_timeout_bits; /* stores the computed timeout */
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static DEFINE_SPINLOCK(ali_lock); /* Guards the hardware */
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/* module parameters */
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static int timeout = WATCHDOG_TIMEOUT;
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module_param(timeout, int, 0);
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MODULE_PARM_DESC(timeout,
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"Watchdog timeout in seconds. (0 < timeout < 18000, default="
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__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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/*
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* ali_start - start watchdog countdown
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*
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* Starts the timer running providing the timer has a counter
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* configuration set.
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*/
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static void ali_start(void)
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{
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u32 val;
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spin_lock(&ali_lock);
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pci_read_config_dword(ali_pci, 0xCC, &val);
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val &= ~0x3F; /* Mask count */
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val |= (1 << 25) | ali_timeout_bits;
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pci_write_config_dword(ali_pci, 0xCC, val);
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spin_unlock(&ali_lock);
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}
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/*
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* ali_stop - stop the timer countdown
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*
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* Stop the ALi watchdog countdown
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*/
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static void ali_stop(void)
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{
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u32 val;
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spin_lock(&ali_lock);
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pci_read_config_dword(ali_pci, 0xCC, &val);
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val &= ~0x3F; /* Mask count to zero (disabled) */
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val &= ~(1 << 25); /* and for safety mask the reset enable */
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pci_write_config_dword(ali_pci, 0xCC, val);
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spin_unlock(&ali_lock);
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}
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/*
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* ali_keepalive - send a keepalive to the watchdog
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*
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* Send a keepalive to the timer (actually we restart the timer).
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*/
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static void ali_keepalive(void)
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{
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ali_start();
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}
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/*
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* ali_settimer - compute the timer reload value
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* @t: time in seconds
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*
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* Computes the timeout values needed
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*/
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static int ali_settimer(int t)
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{
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if (t < 0)
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return -EINVAL;
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else if (t < 60)
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ali_timeout_bits = t|(1 << 6);
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else if (t < 3600)
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ali_timeout_bits = (t / 60)|(1 << 7);
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else if (t < 18000)
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ali_timeout_bits = (t / 300)|(1 << 6)|(1 << 7);
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else
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return -EINVAL;
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timeout = t;
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return 0;
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}
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/*
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* /dev/watchdog handling
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*/
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/*
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* ali_write - writes to ALi watchdog
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* @file: file from VFS
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* @data: user address of data
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* @len: length of data
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* @ppos: pointer to the file offset
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*
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* Handle a write to the ALi watchdog. Writing to the file pings
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* the watchdog and resets it. Writing the magic 'V' sequence allows
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* the next close to turn off the watchdog.
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*/
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static ssize_t ali_write(struct file *file, const char __user *data,
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size_t len, loff_t *ppos)
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{
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/* See if we got the magic character 'V' and reload the timer */
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if (len) {
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if (!nowayout) {
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size_t i;
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/* note: just in case someone wrote the
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magic character five months ago... */
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ali_expect_release = 0;
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/* scan to see whether or not we got
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the magic character */
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for (i = 0; i != len; i++) {
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char c;
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if (get_user(c, data + i))
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return -EFAULT;
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if (c == 'V')
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ali_expect_release = 42;
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}
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}
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/* someone wrote to us, we should reload the timer */
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ali_start();
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}
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return len;
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}
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/*
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* ali_ioctl - handle watchdog ioctls
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* @file: VFS file pointer
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* @cmd: ioctl number
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* @arg: arguments to the ioctl
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*
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* Handle the watchdog ioctls supported by the ALi driver. Really
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* we want an extension to enable irq ack monitoring and the like
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*/
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static long ali_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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void __user *argp = (void __user *)arg;
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int __user *p = argp;
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static const struct watchdog_info ident = {
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.options = WDIOF_KEEPALIVEPING |
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WDIOF_SETTIMEOUT |
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WDIOF_MAGICCLOSE,
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.firmware_version = 0,
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.identity = "ALi M1535 WatchDog Timer",
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};
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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return put_user(0, p);
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case WDIOC_SETOPTIONS:
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{
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int new_options, retval = -EINVAL;
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if (get_user(new_options, p))
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return -EFAULT;
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if (new_options & WDIOS_DISABLECARD) {
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ali_stop();
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retval = 0;
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}
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if (new_options & WDIOS_ENABLECARD) {
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ali_start();
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retval = 0;
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}
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return retval;
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}
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case WDIOC_KEEPALIVE:
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ali_keepalive();
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return 0;
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case WDIOC_SETTIMEOUT:
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{
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int new_timeout;
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if (get_user(new_timeout, p))
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return -EFAULT;
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if (ali_settimer(new_timeout))
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return -EINVAL;
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ali_keepalive();
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}
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fallthrough;
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case WDIOC_GETTIMEOUT:
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return put_user(timeout, p);
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default:
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return -ENOTTY;
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}
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}
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/*
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* ali_open - handle open of ali watchdog
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* @inode: inode from VFS
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* @file: file from VFS
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*
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* Open the ALi watchdog device. Ensure only one person opens it
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* at a time. Also start the watchdog running.
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*/
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static int ali_open(struct inode *inode, struct file *file)
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{
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/* /dev/watchdog can only be opened once */
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if (test_and_set_bit(0, &ali_is_open))
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return -EBUSY;
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/* Activate */
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ali_start();
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return stream_open(inode, file);
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}
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/*
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* ali_release - close an ALi watchdog
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* @inode: inode from VFS
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* @file: file from VFS
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*
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* Close the ALi watchdog device. Actual shutdown of the timer
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* only occurs if the magic sequence has been set.
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*/
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static int ali_release(struct inode *inode, struct file *file)
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{
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/*
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* Shut off the timer.
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*/
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if (ali_expect_release == 42)
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ali_stop();
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else {
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pr_crit("Unexpected close, not stopping watchdog!\n");
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ali_keepalive();
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}
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clear_bit(0, &ali_is_open);
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ali_expect_release = 0;
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return 0;
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}
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/*
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* ali_notify_sys - System down notifier
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*
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* Notifier for system down
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*/
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static int ali_notify_sys(struct notifier_block *this,
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unsigned long code, void *unused)
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{
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if (code == SYS_DOWN || code == SYS_HALT)
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ali_stop(); /* Turn the WDT off */
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return NOTIFY_DONE;
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}
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/*
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* Data for PCI driver interface
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*
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* This data only exists for exporting the supported
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* PCI ids via MODULE_DEVICE_TABLE. We do not actually
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* register a pci_driver, because someone else might one day
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* want to register another driver on the same PCI id.
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*/
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static const struct pci_device_id ali_pci_tbl[] __used = {
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{ PCI_VENDOR_ID_AL, 0x1533, PCI_ANY_ID, PCI_ANY_ID,},
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{ PCI_VENDOR_ID_AL, 0x1535, PCI_ANY_ID, PCI_ANY_ID,},
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{ 0, },
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};
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MODULE_DEVICE_TABLE(pci, ali_pci_tbl);
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/*
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* ali_find_watchdog - find a 1535 and 7101
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*
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* Scans the PCI hardware for a 1535 series bridge and matching 7101
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* watchdog device. This may be overtight but it is better to be safe
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*/
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static int __init ali_find_watchdog(void)
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{
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struct pci_dev *pdev;
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u32 wdog;
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/* Check for a 1533/1535 series bridge */
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pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1535, NULL);
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if (pdev == NULL)
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pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1533, NULL);
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if (pdev == NULL)
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return -ENODEV;
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pci_dev_put(pdev);
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/* Check for the a 7101 PMU */
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pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x7101, NULL);
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if (pdev == NULL)
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return -ENODEV;
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if (pci_enable_device(pdev)) {
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pci_dev_put(pdev);
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return -EIO;
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}
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ali_pci = pdev;
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/*
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* Initialize the timer bits
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*/
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pci_read_config_dword(pdev, 0xCC, &wdog);
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/* Timer bits */
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wdog &= ~0x3F;
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/* Issued events */
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wdog &= ~((1 << 27)|(1 << 26)|(1 << 25)|(1 << 24));
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/* No monitor bits */
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wdog &= ~((1 << 16)|(1 << 13)|(1 << 12)|(1 << 11)|(1 << 10)|(1 << 9));
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pci_write_config_dword(pdev, 0xCC, wdog);
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return 0;
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}
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/*
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* Kernel Interfaces
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*/
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static const struct file_operations ali_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = ali_write,
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.unlocked_ioctl = ali_ioctl,
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.compat_ioctl = compat_ptr_ioctl,
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.open = ali_open,
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.release = ali_release,
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};
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static struct miscdevice ali_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &ali_fops,
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};
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static struct notifier_block ali_notifier = {
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.notifier_call = ali_notify_sys,
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};
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/*
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* watchdog_init - module initialiser
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*
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* Scan for a suitable watchdog and if so initialize it. Return an error
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* if we cannot, the error causes the module to unload
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*/
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static int __init watchdog_init(void)
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{
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int ret;
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/* Check whether or not the hardware watchdog is there */
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if (ali_find_watchdog() != 0)
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return -ENODEV;
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/* Check that the timeout value is within it's range;
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if not reset to the default */
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if (timeout < 1 || timeout >= 18000) {
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timeout = WATCHDOG_TIMEOUT;
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pr_info("timeout value must be 0 < timeout < 18000, using %d\n",
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timeout);
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}
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/* Calculate the watchdog's timeout */
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ali_settimer(timeout);
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ret = register_reboot_notifier(&ali_notifier);
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if (ret != 0) {
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pr_err("cannot register reboot notifier (err=%d)\n", ret);
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goto out;
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}
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ret = misc_register(&ali_miscdev);
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if (ret != 0) {
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pr_err("cannot register miscdev on minor=%d (err=%d)\n",
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WATCHDOG_MINOR, ret);
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goto unreg_reboot;
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}
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pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
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timeout, nowayout);
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out:
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return ret;
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unreg_reboot:
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unregister_reboot_notifier(&ali_notifier);
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goto out;
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}
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/*
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* watchdog_exit - module de-initialiser
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*
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* Called while unloading a successfully installed watchdog module.
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*/
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static void __exit watchdog_exit(void)
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{
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/* Stop the timer before we leave */
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ali_stop();
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/* Deregister */
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misc_deregister(&ali_miscdev);
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unregister_reboot_notifier(&ali_notifier);
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pci_dev_put(ali_pci);
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}
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module_init(watchdog_init);
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module_exit(watchdog_exit);
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MODULE_AUTHOR("Alan Cox");
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MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver");
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MODULE_LICENSE("GPL");
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