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authorWim Van Sebroeck <wim@iguana.be>2007-07-20 17:22:58 -0400
committerWim Van Sebroeck <wim@iguana.be>2007-07-23 13:23:49 -0400
commitde81225a8719494f5149980ea8a50de28da653f6 (patch)
tree6970209ff84cb32a663ca567868b57eb050219ac /drivers/char/watchdog/mpc5200_wdt.c
parent7d831bf59a6991f399170bd2934dad4450891024 (diff)
[WATCHDOG] mpc5200_wdt clean-up
* Add MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); * Add mandatory WDIOC_GETSTATUS and WDIOC_GETBOOTSTATUS ioctl's. * If unknown ioctl is used we should return -ENOTTY. * All watchdog device drivers are VFSs (Virtual File Systems). We thus return a nonseekable_open(inode, file) when we open the VFS. * Make sure that /dev/watchdog can be opened by 1 parent * Add spin-locking to prevent that forked children can disturb each other's operations. Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'drivers/char/watchdog/mpc5200_wdt.c')
-rw-r--r--drivers/char/watchdog/mpc5200_wdt.c32
1 files changed, 30 insertions, 2 deletions
diff --git a/drivers/char/watchdog/mpc5200_wdt.c b/drivers/char/watchdog/mpc5200_wdt.c
index cc3299c03683..564143d40610 100644
--- a/drivers/char/watchdog/mpc5200_wdt.c
+++ b/drivers/char/watchdog/mpc5200_wdt.c
@@ -3,6 +3,7 @@
3#include <linux/miscdevice.h> 3#include <linux/miscdevice.h>
4#include <linux/watchdog.h> 4#include <linux/watchdog.h>
5#include <linux/io.h> 5#include <linux/io.h>
6#include <linux/spinlock.h>
6#include <asm/of_platform.h> 7#include <asm/of_platform.h>
7#include <asm/uaccess.h> 8#include <asm/uaccess.h>
8#include <asm/mpc52xx.h> 9#include <asm/mpc52xx.h>
@@ -19,8 +20,11 @@ struct mpc5200_wdt {
19 struct miscdevice miscdev; 20 struct miscdevice miscdev;
20 struct resource mem; 21 struct resource mem;
21 struct mpc52xx_gpt __iomem *regs; 22 struct mpc52xx_gpt __iomem *regs;
23 spinlock_t io_lock;
22}; 24};
23 25
26/* is_active stores wether or not the /dev/watchdog device is opened */
27static unsigned long is_active;
24 28
25/* misc devices don't provide a way, to get back to 'dev' or 'miscdev' from 29/* misc devices don't provide a way, to get back to 'dev' or 'miscdev' from
26 * file operations, which sucks. But there can be max 1 watchdog anyway, so... 30 * file operations, which sucks. But there can be max 1 watchdog anyway, so...
@@ -47,24 +51,31 @@ static int mpc5200_wdt_get_timeout(struct mpc5200_wdt *wdt)
47/* watchdog operations */ 51/* watchdog operations */
48static int mpc5200_wdt_start(struct mpc5200_wdt *wdt) 52static int mpc5200_wdt_start(struct mpc5200_wdt *wdt)
49{ 53{
54 spin_lock(&wdt->io_lock);
50 /* disable */ 55 /* disable */
51 out_be32(&wdt->regs->mode, 0); 56 out_be32(&wdt->regs->mode, 0);
52 /* set timeout, with maximum prescaler */ 57 /* set timeout, with maximum prescaler */
53 out_be32(&wdt->regs->count, 0x0 | wdt->count); 58 out_be32(&wdt->regs->count, 0x0 | wdt->count);
54 /* enable watchdog */ 59 /* enable watchdog */
55 out_be32(&wdt->regs->mode, GPT_MODE_CE | GPT_MODE_WDT | GPT_MODE_MS_TIMER); 60 out_be32(&wdt->regs->mode, GPT_MODE_CE | GPT_MODE_WDT | GPT_MODE_MS_TIMER);
61 spin_unlock(&wdt->io_lock);
56 62
57 return 0; 63 return 0;
58} 64}
59static int mpc5200_wdt_ping(struct mpc5200_wdt *wdt) 65static int mpc5200_wdt_ping(struct mpc5200_wdt *wdt)
60{ 66{
67 spin_lock(&wdt->io_lock);
61 /* writing A5 to OCPW resets the watchdog */ 68 /* writing A5 to OCPW resets the watchdog */
62 out_be32(&wdt->regs->mode, 0xA5000000 | (0xffffff & in_be32(&wdt->regs->mode))); 69 out_be32(&wdt->regs->mode, 0xA5000000 | (0xffffff & in_be32(&wdt->regs->mode)));
70 spin_unlock(&wdt->io_lock);
63 return 0; 71 return 0;
64} 72}
65static int mpc5200_wdt_stop(struct mpc5200_wdt *wdt) 73static int mpc5200_wdt_stop(struct mpc5200_wdt *wdt)
66{ 74{
75 spin_lock(&wdt->io_lock);
76 /* disable */
67 out_be32(&wdt->regs->mode, 0); 77 out_be32(&wdt->regs->mode, 0);
78 spin_unlock(&wdt->io_lock);
68 return 0; 79 return 0;
69} 80}
70 81
@@ -91,11 +102,17 @@ static int mpc5200_wdt_ioctl(struct inode *inode, struct file *file,
91 102
92 switch (cmd) { 103 switch (cmd) {
93 case WDIOC_GETSUPPORT: 104 case WDIOC_GETSUPPORT:
94 ret = copy_to_user(data, &mpc5200_wdt_info, sizeof(mpc5200_wdt_info)); 105 ret = copy_to_user(data, &mpc5200_wdt_info,
106 sizeof(mpc5200_wdt_info));
95 if (ret) 107 if (ret)
96 ret = -EFAULT; 108 ret = -EFAULT;
97 break; 109 break;
98 110
111 case WDIOC_GETSTATUS:
112 case WDIOC_GETBOOTSTATUS:
113 ret = put_user(0, data);
114 break;
115
99 case WDIOC_KEEPALIVE: 116 case WDIOC_KEEPALIVE:
100 mpc5200_wdt_ping(wdt); 117 mpc5200_wdt_ping(wdt);
101 break; 118 break;
@@ -112,15 +129,23 @@ static int mpc5200_wdt_ioctl(struct inode *inode, struct file *file,
112 timeout = mpc5200_wdt_get_timeout(wdt); 129 timeout = mpc5200_wdt_get_timeout(wdt);
113 ret = put_user(timeout, data); 130 ret = put_user(timeout, data);
114 break; 131 break;
132
133 default:
134 ret = -ENOTTY;
115 } 135 }
116 return ret; 136 return ret;
117} 137}
118static int mpc5200_wdt_open(struct inode *inode, struct file *file) 138static int mpc5200_wdt_open(struct inode *inode, struct file *file)
119{ 139{
140 /* /dev/watchdog can only be opened once */
141 if (test_and_set_bit(0, &is_active))
142 return -EBUSY;
143
144 /* Set and activate the watchdog */
120 mpc5200_wdt_set_timeout(wdt_global, 30); 145 mpc5200_wdt_set_timeout(wdt_global, 30);
121 mpc5200_wdt_start(wdt_global); 146 mpc5200_wdt_start(wdt_global);
122 file->private_data = wdt_global; 147 file->private_data = wdt_global;
123 return 0; 148 return nonseekable_open(inode, file);
124} 149}
125static int mpc5200_wdt_release(struct inode *inode, struct file *file) 150static int mpc5200_wdt_release(struct inode *inode, struct file *file)
126{ 151{
@@ -129,6 +154,7 @@ static int mpc5200_wdt_release(struct inode *inode, struct file *file)
129 mpc5200_wdt_stop(wdt); 154 mpc5200_wdt_stop(wdt);
130 wdt->count = 0; /* == disabled */ 155 wdt->count = 0; /* == disabled */
131#endif 156#endif
157 clear_bit(0, &is_active);
132 return 0; 158 return 0;
133} 159}
134 160
@@ -173,6 +199,7 @@ static int mpc5200_wdt_probe(struct of_device *op, const struct of_device_id *ma
173 } 199 }
174 200
175 dev_set_drvdata(&op->dev, wdt); 201 dev_set_drvdata(&op->dev, wdt);
202 spin_lock_init(&wdt->io_lock);
176 203
177 wdt->miscdev = (struct miscdevice) { 204 wdt->miscdev = (struct miscdevice) {
178 .minor = WATCHDOG_MINOR, 205 .minor = WATCHDOG_MINOR,
@@ -256,3 +283,4 @@ module_exit(mpc5200_wdt_exit);
256 283
257MODULE_AUTHOR("Domen Puncer <domen.puncer@telargo.com>"); 284MODULE_AUTHOR("Domen Puncer <domen.puncer@telargo.com>");
258MODULE_LICENSE("Dual BSD/GPL"); 285MODULE_LICENSE("Dual BSD/GPL");
286MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);