diff options
author | Alejandro Cabrera <aldaya@gmail.com> | 2011-06-02 22:13:11 +0100 |
---|---|---|
committer | Wim Van Sebroeck <wim@iguana.be> | 2011-07-26 21:21:29 +0000 |
commit | e9659e69b0094ea2cc92716e2b1cd6a7db9caf2e (patch) | |
tree | 88dc8beacafc80a19093979ac0d2e7eb45799200 /drivers/watchdog/of_xilinx_wdt.c | |
parent | 2fc5d52b212b58a5b48af19d85cb60971aa1aa4b (diff) |
watchdog: Add Xilinx watchdog timer driver
Watchdog timer device driver for Xilinx xps_timebase_wdt compatible ip cores.
It takes watchdog timer configuration from device tree and it needs that its
parent has defined the property "clock-frecuency".
It is compatible with watchdog timer kernel API, so user apps like watchdogd
may talk with it.
Signed-off-by: Alejandro Cabrera <aldaya@gmail.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'drivers/watchdog/of_xilinx_wdt.c')
-rw-r--r-- | drivers/watchdog/of_xilinx_wdt.c | 433 |
1 files changed, 433 insertions, 0 deletions
diff --git a/drivers/watchdog/of_xilinx_wdt.c b/drivers/watchdog/of_xilinx_wdt.c new file mode 100644 index 00000000000..4ec741ac952 --- /dev/null +++ b/drivers/watchdog/of_xilinx_wdt.c @@ -0,0 +1,433 @@ +/* +* of_xilinx_wdt.c 1.01 A Watchdog Device Driver for Xilinx xps_timebase_wdt +* +* (C) Copyright 2011 (Alejandro Cabrera <aldaya@gmail.com>) +* +* ----------------------- +* +* 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. +* +* ----------------------- +* 30-May-2011 Alejandro Cabrera <aldaya@gmail.com> +* - If "xlnx,wdt-enable-once" wasn't found on device tree the +* module will use CONFIG_WATCHDOG_NOWAYOUT +* - If the device tree parameters ("clock-frequency" and +* "xlnx,wdt-interval") wasn't found the driver won't +* know the wdt reset interval +*/ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/init.h> +#include <linux/ioport.h> +#include <linux/watchdog.h> +#include <linux/io.h> +#include <linux/uaccess.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/of_address.h> + +/* Register offsets for the Wdt device */ +#define XWT_TWCSR0_OFFSET 0x0 /* Control/Status Register0 */ +#define XWT_TWCSR1_OFFSET 0x4 /* Control/Status Register1 */ +#define XWT_TBR_OFFSET 0x8 /* Timebase Register Offset */ + +/* Control/Status Register Masks */ +#define XWT_CSR0_WRS_MASK 0x00000008 /* Reset status */ +#define XWT_CSR0_WDS_MASK 0x00000004 /* Timer state */ +#define XWT_CSR0_EWDT1_MASK 0x00000002 /* Enable bit 1 */ + +/* Control/Status Register 0/1 bits */ +#define XWT_CSRX_EWDT2_MASK 0x00000001 /* Enable bit 2 */ + +/* SelfTest constants */ +#define XWT_MAX_SELFTEST_LOOP_COUNT 0x00010000 +#define XWT_TIMER_FAILED 0xFFFFFFFF + +#define WATCHDOG_NAME "Xilinx Watchdog" +#define PFX WATCHDOG_NAME ": " + +struct xwdt_device { + struct resource res; + void __iomem *base; + u32 nowayout; + u32 wdt_interval; + u32 boot_status; +}; + +static struct xwdt_device xdev; + +static u32 timeout; +static u32 control_status_reg; +static u8 expect_close; +static u8 no_timeout; +static unsigned long driver_open; + +static DEFINE_SPINLOCK(spinlock); + +static void xwdt_start(void) +{ + spin_lock(&spinlock); + + /* Clean previous status and enable the watchdog timer */ + control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET); + control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK); + + iowrite32((control_status_reg | XWT_CSR0_EWDT1_MASK), + xdev.base + XWT_TWCSR0_OFFSET); + + iowrite32(XWT_CSRX_EWDT2_MASK, xdev.base + XWT_TWCSR1_OFFSET); + + spin_unlock(&spinlock); +} + +static void xwdt_stop(void) +{ + spin_lock(&spinlock); + + control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET); + + iowrite32((control_status_reg & ~XWT_CSR0_EWDT1_MASK), + xdev.base + XWT_TWCSR0_OFFSET); + + iowrite32(0, xdev.base + XWT_TWCSR1_OFFSET); + + spin_unlock(&spinlock); + printk(KERN_INFO PFX "Stopped!\n"); +} + +static void xwdt_keepalive(void) +{ + spin_lock(&spinlock); + + control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET); + control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK); + iowrite32(control_status_reg, xdev.base + XWT_TWCSR0_OFFSET); + + spin_unlock(&spinlock); +} + +static void xwdt_get_status(int *status) +{ + int new_status; + + spin_lock(&spinlock); + + control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET); + new_status = ((control_status_reg & + (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK)) != 0); + spin_unlock(&spinlock); + + *status = 0; + if (new_status & 1) + *status |= WDIOF_CARDRESET; +} + +static u32 xwdt_selftest(void) +{ + int i; + u32 timer_value1; + u32 timer_value2; + + spin_lock(&spinlock); + + timer_value1 = ioread32(xdev.base + XWT_TBR_OFFSET); + timer_value2 = ioread32(xdev.base + XWT_TBR_OFFSET); + + for (i = 0; + ((i <= XWT_MAX_SELFTEST_LOOP_COUNT) && + (timer_value2 == timer_value1)); i++) { + timer_value2 = ioread32(xdev.base + XWT_TBR_OFFSET); + } + + spin_unlock(&spinlock); + + if (timer_value2 != timer_value1) + return ~XWT_TIMER_FAILED; + else + return XWT_TIMER_FAILED; +} + +static int xwdt_open(struct inode *inode, struct file *file) +{ + /* Only one process can handle the wdt at a time */ + if (test_and_set_bit(0, &driver_open)) + return -EBUSY; + + /* Make sure that the module are always loaded...*/ + if (xdev.nowayout) + __module_get(THIS_MODULE); + + xwdt_start(); + printk(KERN_INFO PFX "Started...\n"); + + return nonseekable_open(inode, file); +} + +static int xwdt_release(struct inode *inode, struct file *file) +{ + if (expect_close == 42) { + xwdt_stop(); + } else { + printk(KERN_CRIT PFX + "Unexpected close, not stopping watchdog!\n"); + xwdt_keepalive(); + } + + clear_bit(0, &driver_open); + expect_close = 0; + return 0; +} + +/* + * xwdt_write: + * @file: file handle to the watchdog + * @buf: buffer to write (unused as data does not matter here + * @count: count of bytes + * @ppos: pointer to the position to write. No seeks allowed + * + * A write to a watchdog device is defined as a keepalive signal. Any + * write of data will do, as we don't define content meaning. + */ +static ssize_t xwdt_write(struct file *file, const char __user *buf, + size_t len, loff_t *ppos) +{ + if (len) { + if (!xdev.nowayout) { + size_t i; + + /* In case it was set long ago */ + expect_close = 0; + + for (i = 0; i != len; i++) { + char c; + + if (get_user(c, buf + i)) + return -EFAULT; + if (c == 'V') + expect_close = 42; + } + } + xwdt_keepalive(); + } + return len; +} + +static const struct watchdog_info ident = { + .options = WDIOF_MAGICCLOSE | + WDIOF_KEEPALIVEPING, + .firmware_version = 1, + .identity = WATCHDOG_NAME, +}; + +/* + * xwdt_ioctl: + * @file: file handle to the device + * @cmd: watchdog command + * @arg: argument pointer + * + * The watchdog API defines a common set of functions for all watchdogs + * according to their available features. + */ +static long xwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + int status; + + union { + struct watchdog_info __user *ident; + int __user *i; + } uarg; + + uarg.i = (int __user *)arg; + + switch (cmd) { + case WDIOC_GETSUPPORT: + return copy_to_user(uarg.ident, &ident, + sizeof(ident)) ? -EFAULT : 0; + + case WDIOC_GETBOOTSTATUS: + return put_user(xdev.boot_status, uarg.i); + + case WDIOC_GETSTATUS: + xwdt_get_status(&status); + return put_user(status, uarg.i); + + case WDIOC_KEEPALIVE: + xwdt_keepalive(); + return 0; + + case WDIOC_GETTIMEOUT: + if (no_timeout) + return -ENOTTY; + else + return put_user(timeout, uarg.i); + + default: + return -ENOTTY; + } +} + +static const struct file_operations xwdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = xwdt_write, + .open = xwdt_open, + .release = xwdt_release, + .unlocked_ioctl = xwdt_ioctl, +}; + +static struct miscdevice xwdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &xwdt_fops, +}; + +static int __devinit xwdt_probe(struct platform_device *pdev) +{ + int rc; + u32 *tmptr; + u32 *pfreq; + + no_timeout = 0; + + pfreq = (u32 *)of_get_property(pdev->dev.of_node->parent, + "clock-frequency", NULL); + + if (pfreq == NULL) { + printk(KERN_WARNING PFX + "The watchdog clock frequency cannot be obtained!\n"); + no_timeout = 1; + } + + rc = of_address_to_resource(pdev->dev.of_node, 0, &xdev.res); + if (rc) { + printk(KERN_WARNING PFX "invalid address!\n"); + return rc; + } + + tmptr = (u32 *)of_get_property(pdev->dev.of_node, + "xlnx,wdt-interval", NULL); + if (tmptr == NULL) { + printk(KERN_WARNING PFX "Parameter \"xlnx,wdt-interval\"" + " not found in device tree!\n"); + no_timeout = 1; + } else { + xdev.wdt_interval = *tmptr; + } + + tmptr = (u32 *)of_get_property(pdev->dev.of_node, + "xlnx,wdt-enable-once", NULL); + if (tmptr == NULL) { + printk(KERN_WARNING PFX "Parameter \"xlnx,wdt-enable-once\"" + " not found in device tree!\n"); + xdev.nowayout = WATCHDOG_NOWAYOUT; + } + +/* + * Twice of the 2^wdt_interval / freq because the first wdt overflow is + * ignored (interrupt), reset is only generated at second wdt overflow + */ + if (!no_timeout) + timeout = 2 * ((1<<xdev.wdt_interval) / *pfreq); + + if (!request_mem_region(xdev.res.start, + xdev.res.end - xdev.res.start + 1, WATCHDOG_NAME)) { + rc = -ENXIO; + printk(KERN_ERR PFX "memory request failure!\n"); + goto err_out; + } + + xdev.base = ioremap(xdev.res.start, xdev.res.end - xdev.res.start + 1); + if (xdev.base == NULL) { + rc = -ENOMEM; + printk(KERN_ERR PFX "ioremap failure!\n"); + goto release_mem; + } + + rc = xwdt_selftest(); + if (rc == XWT_TIMER_FAILED) { + printk(KERN_ERR PFX "SelfTest routine error!\n"); + goto unmap_io; + } + + xwdt_get_status(&xdev.boot_status); + + rc = misc_register(&xwdt_miscdev); + if (rc) { + printk(KERN_ERR PFX + "cannot register miscdev on minor=%d (err=%d)\n", + xwdt_miscdev.minor, rc); + goto unmap_io; + } + + if (no_timeout) + printk(KERN_INFO PFX + "driver loaded (timeout=? sec, nowayout=%d)\n", + xdev.nowayout); + else + printk(KERN_INFO PFX + "driver loaded (timeout=%d sec, nowayout=%d)\n", + timeout, xdev.nowayout); + + expect_close = 0; + clear_bit(0, &driver_open); + + return 0; + +unmap_io: + iounmap(xdev.base); +release_mem: + release_mem_region(xdev.res.start, resource_size(&xdev.res)); +err_out: + return rc; +} + +static int __devexit xwdt_remove(struct platform_device *dev) +{ + misc_deregister(&xwdt_miscdev); + iounmap(xdev.base); + release_mem_region(xdev.res.start, resource_size(&xdev.res)); + + return 0; +} + +/* Match table for of_platform binding */ +static struct of_device_id __devinitdata xwdt_of_match[] = { + { .compatible = "xlnx,xps-timebase-wdt-1.01.a", }, + {}, +}; +MODULE_DEVICE_TABLE(of, xwdt_of_match); + +static struct platform_driver xwdt_driver = { + .probe = xwdt_probe, + .remove = __devexit_p(xwdt_remove), + .driver = { + .owner = THIS_MODULE, + .name = WATCHDOG_NAME, + .of_match_table = xwdt_of_match, + }, +}; + +static int __init xwdt_init(void) +{ + return platform_driver_register(&xwdt_driver); +} + +static void __exit xwdt_exit(void) +{ + platform_driver_unregister(&xwdt_driver); +} + +module_init(xwdt_init); +module_exit(xwdt_exit); + +MODULE_AUTHOR("Alejandro Cabrera <aldaya@gmail.com>"); +MODULE_DESCRIPTION("Xilinx Watchdog driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |