kernel_optimize_test/drivers/watchdog/davinci_wdt.c
Jean Delvare 487722cf2d watchdog: Get rid of MODULE_ALIAS_MISCDEV statements
I just can't find any value in MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR)
and MODULE_ALIAS_MISCDEV(TEMP_MINOR) statements.

Either the device is enumerated and the driver already has a module
alias (e.g. PCI, USB etc.) that will get the right driver loaded
automatically.

Or the device is not enumerated and loading its driver will lead to
more or less intrusive hardware poking. Such hardware poking should be
limited to a bare minimum, so the user should really decide which
drivers should be tried and in what order. Trying them all in
arbitrary order can't do any good.

On top of that, loading that many drivers at once bloats the kernel
log. Also many drivers will stay loaded afterward, bloating the output
of "lsmod" and wasting memory. Some modules (cs5535_mfgpt which gets
loaded as a dependency) can't even be unloaded!

If defining char-major-10-130 is needed then it should happen in
user-space.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Cc: Jim Cromie <jim.cromie@gmail.com>
2013-11-17 19:38:13 +01:00

271 lines
6.3 KiB
C

/*
* drivers/char/watchdog/davinci_wdt.c
*
* Watchdog driver for DaVinci DM644x/DM646x processors
*
* Copyright (C) 2006 Texas Instruments.
*
* 2007 (c) MontaVista Software, Inc. This file is licensed under
* the terms of the GNU General Public License version 2. This program
* is licensed "as is" without any warranty of any kind, whether express
* or implied.
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/err.h>
#define MODULE_NAME "DAVINCI-WDT: "
#define DEFAULT_HEARTBEAT 60
#define MAX_HEARTBEAT 600 /* really the max margin is 264/27MHz*/
/* Timer register set definition */
#define PID12 (0x0)
#define EMUMGT (0x4)
#define TIM12 (0x10)
#define TIM34 (0x14)
#define PRD12 (0x18)
#define PRD34 (0x1C)
#define TCR (0x20)
#define TGCR (0x24)
#define WDTCR (0x28)
/* TCR bit definitions */
#define ENAMODE12_DISABLED (0 << 6)
#define ENAMODE12_ONESHOT (1 << 6)
#define ENAMODE12_PERIODIC (2 << 6)
/* TGCR bit definitions */
#define TIM12RS_UNRESET (1 << 0)
#define TIM34RS_UNRESET (1 << 1)
#define TIMMODE_64BIT_WDOG (2 << 2)
/* WDTCR bit definitions */
#define WDEN (1 << 14)
#define WDFLAG (1 << 15)
#define WDKEY_SEQ0 (0xa5c6 << 16)
#define WDKEY_SEQ1 (0xda7e << 16)
static int heartbeat = DEFAULT_HEARTBEAT;
static DEFINE_SPINLOCK(io_lock);
static unsigned long wdt_status;
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
#define WDT_REGION_INITED 2
#define WDT_DEVICE_INITED 3
static void __iomem *wdt_base;
struct clk *wdt_clk;
static void wdt_service(void)
{
spin_lock(&io_lock);
/* put watchdog in service state */
iowrite32(WDKEY_SEQ0, wdt_base + WDTCR);
/* put watchdog in active state */
iowrite32(WDKEY_SEQ1, wdt_base + WDTCR);
spin_unlock(&io_lock);
}
static void wdt_enable(void)
{
u32 tgcr;
u32 timer_margin;
unsigned long wdt_freq;
wdt_freq = clk_get_rate(wdt_clk);
spin_lock(&io_lock);
/* disable, internal clock source */
iowrite32(0, wdt_base + TCR);
/* reset timer, set mode to 64-bit watchdog, and unreset */
iowrite32(0, wdt_base + TGCR);
tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
iowrite32(tgcr, wdt_base + TGCR);
/* clear counter regs */
iowrite32(0, wdt_base + TIM12);
iowrite32(0, wdt_base + TIM34);
/* set timeout period */
timer_margin = (((u64)heartbeat * wdt_freq) & 0xffffffff);
iowrite32(timer_margin, wdt_base + PRD12);
timer_margin = (((u64)heartbeat * wdt_freq) >> 32);
iowrite32(timer_margin, wdt_base + PRD34);
/* enable run continuously */
iowrite32(ENAMODE12_PERIODIC, wdt_base + TCR);
/* Once the WDT is in pre-active state write to
* TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are
* write protected (except for the WDKEY field)
*/
/* put watchdog in pre-active state */
iowrite32(WDKEY_SEQ0 | WDEN, wdt_base + WDTCR);
/* put watchdog in active state */
iowrite32(WDKEY_SEQ1 | WDEN, wdt_base + WDTCR);
spin_unlock(&io_lock);
}
static int davinci_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(WDT_IN_USE, &wdt_status))
return -EBUSY;
wdt_enable();
return nonseekable_open(inode, file);
}
static ssize_t
davinci_wdt_write(struct file *file, const char *data, size_t len,
loff_t *ppos)
{
if (len)
wdt_service();
return len;
}
static const struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING,
.identity = "DaVinci Watchdog",
};
static long davinci_wdt_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
int ret = -ENOTTY;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user((struct watchdog_info *)arg, &ident,
sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_KEEPALIVE:
wdt_service();
ret = 0;
break;
case WDIOC_GETTIMEOUT:
ret = put_user(heartbeat, (int *)arg);
break;
}
return ret;
}
static int davinci_wdt_release(struct inode *inode, struct file *file)
{
wdt_service();
clear_bit(WDT_IN_USE, &wdt_status);
return 0;
}
static const struct file_operations davinci_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = davinci_wdt_write,
.unlocked_ioctl = davinci_wdt_ioctl,
.open = davinci_wdt_open,
.release = davinci_wdt_release,
};
static struct miscdevice davinci_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &davinci_wdt_fops,
};
static int davinci_wdt_probe(struct platform_device *pdev)
{
int ret = 0;
struct device *dev = &pdev->dev;
struct resource *wdt_mem;
wdt_clk = devm_clk_get(dev, NULL);
if (WARN_ON(IS_ERR(wdt_clk)))
return PTR_ERR(wdt_clk);
clk_prepare_enable(wdt_clk);
if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
heartbeat = DEFAULT_HEARTBEAT;
dev_info(dev, "heartbeat %d sec\n", heartbeat);
wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
wdt_base = devm_ioremap_resource(dev, wdt_mem);
if (IS_ERR(wdt_base))
return PTR_ERR(wdt_base);
ret = misc_register(&davinci_wdt_miscdev);
if (ret < 0) {
dev_err(dev, "cannot register misc device\n");
} else {
set_bit(WDT_DEVICE_INITED, &wdt_status);
}
return ret;
}
static int davinci_wdt_remove(struct platform_device *pdev)
{
misc_deregister(&davinci_wdt_miscdev);
clk_disable_unprepare(wdt_clk);
return 0;
}
static const struct of_device_id davinci_wdt_of_match[] = {
{ .compatible = "ti,davinci-wdt", },
{},
};
MODULE_DEVICE_TABLE(of, davinci_wdt_of_match);
static struct platform_driver platform_wdt_driver = {
.driver = {
.name = "watchdog",
.owner = THIS_MODULE,
.of_match_table = davinci_wdt_of_match,
},
.probe = davinci_wdt_probe,
.remove = davinci_wdt_remove,
};
module_platform_driver(platform_wdt_driver);
MODULE_AUTHOR("Texas Instruments");
MODULE_DESCRIPTION("DaVinci Watchdog Driver");
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeat period in seconds from 1 to "
__MODULE_STRING(MAX_HEARTBEAT) ", default "
__MODULE_STRING(DEFAULT_HEARTBEAT));
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:watchdog");