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-rw-r--r--drivers/watchdog/cpwd.c663
1 files changed, 663 insertions, 0 deletions
diff --git a/drivers/watchdog/cpwd.c b/drivers/watchdog/cpwd.c
new file mode 100644
index 000000000..808eeb477
--- /dev/null
+++ b/drivers/watchdog/cpwd.c
@@ -0,0 +1,663 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* cpwd.c - driver implementation for hardware watchdog
+ * timers found on Sun Microsystems CP1400 and CP1500 boards.
+ *
+ * This device supports both the generic Linux watchdog
+ * interface and Solaris-compatible ioctls as best it is
+ * able.
+ *
+ * NOTE: CP1400 systems appear to have a defective intr_mask
+ * register on the PLD, preventing the disabling of
+ * timer interrupts. We use a timer to periodically
+ * reset 'stopped' watchdogs on affected platforms.
+ *
+ * Copyright (c) 2000 Eric Brower (ebrower@usa.net)
+ * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/errno.h>
+#include <linux/major.h>
+#include <linux/miscdevice.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/timer.h>
+#include <linux/compat.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/uaccess.h>
+
+#include <asm/irq.h>
+#include <asm/watchdog.h>
+
+#define DRIVER_NAME "cpwd"
+
+#define WD_OBPNAME "watchdog"
+#define WD_BADMODEL "SUNW,501-5336"
+#define WD_BTIMEOUT (jiffies + (HZ * 1000))
+#define WD_BLIMIT 0xFFFF
+
+#define WD0_MINOR 212
+#define WD1_MINOR 213
+#define WD2_MINOR 214
+
+/* Internal driver definitions. */
+#define WD0_ID 0
+#define WD1_ID 1
+#define WD2_ID 2
+#define WD_NUMDEVS 3
+
+#define WD_INTR_OFF 0
+#define WD_INTR_ON 1
+
+#define WD_STAT_INIT 0x01 /* Watchdog timer is initialized */
+#define WD_STAT_BSTOP 0x02 /* Watchdog timer is brokenstopped */
+#define WD_STAT_SVCD 0x04 /* Watchdog interrupt occurred */
+
+/* Register value definitions
+ */
+#define WD0_INTR_MASK 0x01 /* Watchdog device interrupt masks */
+#define WD1_INTR_MASK 0x02
+#define WD2_INTR_MASK 0x04
+
+#define WD_S_RUNNING 0x01 /* Watchdog device status running */
+#define WD_S_EXPIRED 0x02 /* Watchdog device status expired */
+
+struct cpwd {
+ void __iomem *regs;
+ spinlock_t lock;
+
+ unsigned int irq;
+
+ unsigned long timeout;
+ bool enabled;
+ bool reboot;
+ bool broken;
+ bool initialized;
+
+ struct {
+ struct miscdevice misc;
+ void __iomem *regs;
+ u8 intr_mask;
+ u8 runstatus;
+ u16 timeout;
+ } devs[WD_NUMDEVS];
+};
+
+static DEFINE_MUTEX(cpwd_mutex);
+static struct cpwd *cpwd_device;
+
+/* Sun uses Altera PLD EPF8820ATC144-4
+ * providing three hardware watchdogs:
+ *
+ * 1) RIC - sends an interrupt when triggered
+ * 2) XIR - asserts XIR_B_RESET when triggered, resets CPU
+ * 3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board
+ *
+ *** Timer register block definition (struct wd_timer_regblk)
+ *
+ * dcntr and limit registers (halfword access):
+ * -------------------
+ * | 15 | ...| 1 | 0 |
+ * -------------------
+ * |- counter val -|
+ * -------------------
+ * dcntr - Current 16-bit downcounter value.
+ * When downcounter reaches '0' watchdog expires.
+ * Reading this register resets downcounter with
+ * 'limit' value.
+ * limit - 16-bit countdown value in 1/10th second increments.
+ * Writing this register begins countdown with input value.
+ * Reading from this register does not affect counter.
+ * NOTES: After watchdog reset, dcntr and limit contain '1'
+ *
+ * status register (byte access):
+ * ---------------------------
+ * | 7 | ... | 2 | 1 | 0 |
+ * --------------+------------
+ * |- UNUSED -| EXP | RUN |
+ * ---------------------------
+ * status- Bit 0 - Watchdog is running
+ * Bit 1 - Watchdog has expired
+ *
+ *** PLD register block definition (struct wd_pld_regblk)
+ *
+ * intr_mask register (byte access):
+ * ---------------------------------
+ * | 7 | ... | 3 | 2 | 1 | 0 |
+ * +-------------+------------------
+ * |- UNUSED -| WD3 | WD2 | WD1 |
+ * ---------------------------------
+ * WD3 - 1 == Interrupt disabled for watchdog 3
+ * WD2 - 1 == Interrupt disabled for watchdog 2
+ * WD1 - 1 == Interrupt disabled for watchdog 1
+ *
+ * pld_status register (byte access):
+ * UNKNOWN, MAGICAL MYSTERY REGISTER
+ *
+ */
+#define WD_TIMER_REGSZ 16
+#define WD0_OFF 0
+#define WD1_OFF (WD_TIMER_REGSZ * 1)
+#define WD2_OFF (WD_TIMER_REGSZ * 2)
+#define PLD_OFF (WD_TIMER_REGSZ * 3)
+
+#define WD_DCNTR 0x00
+#define WD_LIMIT 0x04
+#define WD_STATUS 0x08
+
+#define PLD_IMASK (PLD_OFF + 0x00)
+#define PLD_STATUS (PLD_OFF + 0x04)
+
+static struct timer_list cpwd_timer;
+
+static int wd0_timeout;
+static int wd1_timeout;
+static int wd2_timeout;
+
+module_param(wd0_timeout, int, 0);
+MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs");
+module_param(wd1_timeout, int, 0);
+MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs");
+module_param(wd2_timeout, int, 0);
+MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs");
+
+MODULE_AUTHOR("Eric Brower <ebrower@usa.net>");
+MODULE_DESCRIPTION("Hardware watchdog driver for Sun Microsystems CP1400/1500");
+MODULE_LICENSE("GPL");
+MODULE_SUPPORTED_DEVICE("watchdog");
+
+static void cpwd_writew(u16 val, void __iomem *addr)
+{
+ writew(cpu_to_le16(val), addr);
+}
+static u16 cpwd_readw(void __iomem *addr)
+{
+ u16 val = readw(addr);
+
+ return le16_to_cpu(val);
+}
+
+static void cpwd_writeb(u8 val, void __iomem *addr)
+{
+ writeb(val, addr);
+}
+
+static u8 cpwd_readb(void __iomem *addr)
+{
+ return readb(addr);
+}
+
+/* Enable or disable watchdog interrupts
+ * Because of the CP1400 defect this should only be
+ * called during initialzation or by wd_[start|stop]timer()
+ *
+ * index - sub-device index, or -1 for 'all'
+ * enable - non-zero to enable interrupts, zero to disable
+ */
+static void cpwd_toggleintr(struct cpwd *p, int index, int enable)
+{
+ unsigned char curregs = cpwd_readb(p->regs + PLD_IMASK);
+ unsigned char setregs =
+ (index == -1) ?
+ (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) :
+ (p->devs[index].intr_mask);
+
+ if (enable == WD_INTR_ON)
+ curregs &= ~setregs;
+ else
+ curregs |= setregs;
+
+ cpwd_writeb(curregs, p->regs + PLD_IMASK);
+}
+
+/* Restarts timer with maximum limit value and
+ * does not unset 'brokenstop' value.
+ */
+static void cpwd_resetbrokentimer(struct cpwd *p, int index)
+{
+ cpwd_toggleintr(p, index, WD_INTR_ON);
+ cpwd_writew(WD_BLIMIT, p->devs[index].regs + WD_LIMIT);
+}
+
+/* Timer method called to reset stopped watchdogs--
+ * because of the PLD bug on CP1400, we cannot mask
+ * interrupts within the PLD so me must continually
+ * reset the timers ad infinitum.
+ */
+static void cpwd_brokentimer(struct timer_list *unused)
+{
+ struct cpwd *p = cpwd_device;
+ int id, tripped = 0;
+
+ /* kill a running timer instance, in case we
+ * were called directly instead of by kernel timer
+ */
+ if (timer_pending(&cpwd_timer))
+ del_timer(&cpwd_timer);
+
+ for (id = 0; id < WD_NUMDEVS; id++) {
+ if (p->devs[id].runstatus & WD_STAT_BSTOP) {
+ ++tripped;
+ cpwd_resetbrokentimer(p, id);
+ }
+ }
+
+ if (tripped) {
+ /* there is at least one timer brokenstopped-- reschedule */
+ cpwd_timer.expires = WD_BTIMEOUT;
+ add_timer(&cpwd_timer);
+ }
+}
+
+/* Reset countdown timer with 'limit' value and continue countdown.
+ * This will not start a stopped timer.
+ */
+static void cpwd_pingtimer(struct cpwd *p, int index)
+{
+ if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING)
+ cpwd_readw(p->devs[index].regs + WD_DCNTR);
+}
+
+/* Stop a running watchdog timer-- the timer actually keeps
+ * running, but the interrupt is masked so that no action is
+ * taken upon expiration.
+ */
+static void cpwd_stoptimer(struct cpwd *p, int index)
+{
+ if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) {
+ cpwd_toggleintr(p, index, WD_INTR_OFF);
+
+ if (p->broken) {
+ p->devs[index].runstatus |= WD_STAT_BSTOP;
+ cpwd_brokentimer(NULL);
+ }
+ }
+}
+
+/* Start a watchdog timer with the specified limit value
+ * If the watchdog is running, it will be restarted with
+ * the provided limit value.
+ *
+ * This function will enable interrupts on the specified
+ * watchdog.
+ */
+static void cpwd_starttimer(struct cpwd *p, int index)
+{
+ if (p->broken)
+ p->devs[index].runstatus &= ~WD_STAT_BSTOP;
+
+ p->devs[index].runstatus &= ~WD_STAT_SVCD;
+
+ cpwd_writew(p->devs[index].timeout, p->devs[index].regs + WD_LIMIT);
+ cpwd_toggleintr(p, index, WD_INTR_ON);
+}
+
+static int cpwd_getstatus(struct cpwd *p, int index)
+{
+ unsigned char stat = cpwd_readb(p->devs[index].regs + WD_STATUS);
+ unsigned char intr = cpwd_readb(p->devs[index].regs + PLD_IMASK);
+ unsigned char ret = WD_STOPPED;
+
+ /* determine STOPPED */
+ if (!stat)
+ return ret;
+
+ /* determine EXPIRED vs FREERUN vs RUNNING */
+ else if (WD_S_EXPIRED & stat) {
+ ret = WD_EXPIRED;
+ } else if (WD_S_RUNNING & stat) {
+ if (intr & p->devs[index].intr_mask) {
+ ret = WD_FREERUN;
+ } else {
+ /* Fudge WD_EXPIRED status for defective CP1400--
+ * IF timer is running
+ * AND brokenstop is set
+ * AND an interrupt has been serviced
+ * we are WD_EXPIRED.
+ *
+ * IF timer is running
+ * AND brokenstop is set
+ * AND no interrupt has been serviced
+ * we are WD_FREERUN.
+ */
+ if (p->broken &&
+ (p->devs[index].runstatus & WD_STAT_BSTOP)) {
+ if (p->devs[index].runstatus & WD_STAT_SVCD) {
+ ret = WD_EXPIRED;
+ } else {
+ /* we could as well pretend
+ * we are expired */
+ ret = WD_FREERUN;
+ }
+ } else {
+ ret = WD_RUNNING;
+ }
+ }
+ }
+
+ /* determine SERVICED */
+ if (p->devs[index].runstatus & WD_STAT_SVCD)
+ ret |= WD_SERVICED;
+
+ return ret;
+}
+
+static irqreturn_t cpwd_interrupt(int irq, void *dev_id)
+{
+ struct cpwd *p = dev_id;
+
+ /* Only WD0 will interrupt-- others are NMI and we won't
+ * see them here....
+ */
+ spin_lock_irq(&p->lock);
+
+ cpwd_stoptimer(p, WD0_ID);
+ p->devs[WD0_ID].runstatus |= WD_STAT_SVCD;
+
+ spin_unlock_irq(&p->lock);
+
+ return IRQ_HANDLED;
+}
+
+static int cpwd_open(struct inode *inode, struct file *f)
+{
+ struct cpwd *p = cpwd_device;
+
+ mutex_lock(&cpwd_mutex);
+ switch (iminor(inode)) {
+ case WD0_MINOR:
+ case WD1_MINOR:
+ case WD2_MINOR:
+ break;
+
+ default:
+ mutex_unlock(&cpwd_mutex);
+ return -ENODEV;
+ }
+
+ /* Register IRQ on first open of device */
+ if (!p->initialized) {
+ if (request_irq(p->irq, &cpwd_interrupt,
+ IRQF_SHARED, DRIVER_NAME, p)) {
+ pr_err("Cannot register IRQ %d\n", p->irq);
+ mutex_unlock(&cpwd_mutex);
+ return -EBUSY;
+ }
+ p->initialized = true;
+ }
+
+ mutex_unlock(&cpwd_mutex);
+
+ return stream_open(inode, f);
+}
+
+static int cpwd_release(struct inode *inode, struct file *file)
+{
+ return 0;
+}
+
+static long cpwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ static const struct watchdog_info info = {
+ .options = WDIOF_SETTIMEOUT,
+ .firmware_version = 1,
+ .identity = DRIVER_NAME,
+ };
+ void __user *argp = (void __user *)arg;
+ struct inode *inode = file_inode(file);
+ int index = iminor(inode) - WD0_MINOR;
+ struct cpwd *p = cpwd_device;
+ int setopt = 0;
+
+ switch (cmd) {
+ /* Generic Linux IOCTLs */
+ case WDIOC_GETSUPPORT:
+ if (copy_to_user(argp, &info, sizeof(struct watchdog_info)))
+ return -EFAULT;
+ break;
+
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ if (put_user(0, (int __user *)argp))
+ return -EFAULT;
+ break;
+
+ case WDIOC_KEEPALIVE:
+ cpwd_pingtimer(p, index);
+ break;
+
+ case WDIOC_SETOPTIONS:
+ if (copy_from_user(&setopt, argp, sizeof(unsigned int)))
+ return -EFAULT;
+
+ if (setopt & WDIOS_DISABLECARD) {
+ if (p->enabled)
+ return -EINVAL;
+ cpwd_stoptimer(p, index);
+ } else if (setopt & WDIOS_ENABLECARD) {
+ cpwd_starttimer(p, index);
+ } else {
+ return -EINVAL;
+ }
+ break;
+
+ /* Solaris-compatible IOCTLs */
+ case WIOCGSTAT:
+ setopt = cpwd_getstatus(p, index);
+ if (copy_to_user(argp, &setopt, sizeof(unsigned int)))
+ return -EFAULT;
+ break;
+
+ case WIOCSTART:
+ cpwd_starttimer(p, index);
+ break;
+
+ case WIOCSTOP:
+ if (p->enabled)
+ return -EINVAL;
+
+ cpwd_stoptimer(p, index);
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static long cpwd_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ return cpwd_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+
+static ssize_t cpwd_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct inode *inode = file_inode(file);
+ struct cpwd *p = cpwd_device;
+ int index = iminor(inode);
+
+ if (count) {
+ cpwd_pingtimer(p, index);
+ return 1;
+ }
+
+ return 0;
+}
+
+static ssize_t cpwd_read(struct file *file, char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ return -EINVAL;
+}
+
+static const struct file_operations cpwd_fops = {
+ .owner = THIS_MODULE,
+ .unlocked_ioctl = cpwd_ioctl,
+ .compat_ioctl = cpwd_compat_ioctl,
+ .open = cpwd_open,
+ .write = cpwd_write,
+ .read = cpwd_read,
+ .release = cpwd_release,
+ .llseek = no_llseek,
+};
+
+static int cpwd_probe(struct platform_device *op)
+{
+ struct device_node *options;
+ const char *str_prop;
+ const void *prop_val;
+ int i, err = -EINVAL;
+ struct cpwd *p;
+
+ if (cpwd_device)
+ return -EINVAL;
+
+ p = devm_kzalloc(&op->dev, sizeof(*p), GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+
+ p->irq = op->archdata.irqs[0];
+
+ spin_lock_init(&p->lock);
+
+ p->regs = of_ioremap(&op->resource[0], 0,
+ 4 * WD_TIMER_REGSZ, DRIVER_NAME);
+ if (!p->regs) {
+ pr_err("Unable to map registers\n");
+ return -ENOMEM;
+ }
+
+ options = of_find_node_by_path("/options");
+ if (!options) {
+ err = -ENODEV;
+ pr_err("Unable to find /options node\n");
+ goto out_iounmap;
+ }
+
+ prop_val = of_get_property(options, "watchdog-enable?", NULL);
+ p->enabled = (prop_val ? true : false);
+
+ prop_val = of_get_property(options, "watchdog-reboot?", NULL);
+ p->reboot = (prop_val ? true : false);
+
+ str_prop = of_get_property(options, "watchdog-timeout", NULL);
+ if (str_prop)
+ p->timeout = simple_strtoul(str_prop, NULL, 10);
+
+ of_node_put(options);
+
+ /* CP1400s seem to have broken PLD implementations-- the
+ * interrupt_mask register cannot be written, so no timer
+ * interrupts can be masked within the PLD.
+ */
+ str_prop = of_get_property(op->dev.of_node, "model", NULL);
+ p->broken = (str_prop && !strcmp(str_prop, WD_BADMODEL));
+
+ if (!p->enabled)
+ cpwd_toggleintr(p, -1, WD_INTR_OFF);
+
+ for (i = 0; i < WD_NUMDEVS; i++) {
+ static const char *cpwd_names[] = { "RIC", "XIR", "POR" };
+ static int *parms[] = { &wd0_timeout,
+ &wd1_timeout,
+ &wd2_timeout };
+ struct miscdevice *mp = &p->devs[i].misc;
+
+ mp->minor = WD0_MINOR + i;
+ mp->name = cpwd_names[i];
+ mp->fops = &cpwd_fops;
+
+ p->devs[i].regs = p->regs + (i * WD_TIMER_REGSZ);
+ p->devs[i].intr_mask = (WD0_INTR_MASK << i);
+ p->devs[i].runstatus &= ~WD_STAT_BSTOP;
+ p->devs[i].runstatus |= WD_STAT_INIT;
+ p->devs[i].timeout = p->timeout;
+ if (*parms[i])
+ p->devs[i].timeout = *parms[i];
+
+ err = misc_register(&p->devs[i].misc);
+ if (err) {
+ pr_err("Could not register misc device for dev %d\n",
+ i);
+ goto out_unregister;
+ }
+ }
+
+ if (p->broken) {
+ timer_setup(&cpwd_timer, cpwd_brokentimer, 0);
+ cpwd_timer.expires = WD_BTIMEOUT;
+
+ pr_info("PLD defect workaround enabled for model %s\n",
+ WD_BADMODEL);
+ }
+
+ platform_set_drvdata(op, p);
+ cpwd_device = p;
+ return 0;
+
+out_unregister:
+ for (i--; i >= 0; i--)
+ misc_deregister(&p->devs[i].misc);
+
+out_iounmap:
+ of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
+
+ return err;
+}
+
+static int cpwd_remove(struct platform_device *op)
+{
+ struct cpwd *p = platform_get_drvdata(op);
+ int i;
+
+ for (i = 0; i < WD_NUMDEVS; i++) {
+ misc_deregister(&p->devs[i].misc);
+
+ if (!p->enabled) {
+ cpwd_stoptimer(p, i);
+ if (p->devs[i].runstatus & WD_STAT_BSTOP)
+ cpwd_resetbrokentimer(p, i);
+ }
+ }
+
+ if (p->broken)
+ del_timer_sync(&cpwd_timer);
+
+ if (p->initialized)
+ free_irq(p->irq, p);
+
+ of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
+
+ cpwd_device = NULL;
+
+ return 0;
+}
+
+static const struct of_device_id cpwd_match[] = {
+ {
+ .name = "watchdog",
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, cpwd_match);
+
+static struct platform_driver cpwd_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ .of_match_table = cpwd_match,
+ },
+ .probe = cpwd_probe,
+ .remove = cpwd_remove,
+};
+
+module_platform_driver(cpwd_driver);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 08:16:06 +0000