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linux-next/drivers/watchdog/coh901327_wdt.c
Paul Gortmaker 73027cb8e8 watchdog: coh901327: make it explicitly non-modular 
The Kconfig currently controlling compilation of this code is:

config COH901327_WATCHDOG
       bool "ST-Ericsson COH 901 327 watchdog"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

We explicitly disallow a driver unbind, since that doesn't have a
sensible use case anyway, and it allows us to drop the ".remove"
code for non-modular drivers.

Since module_platform_driver() uses the same init level priority as
builtin_platform_driver() the init ordering remains unchanged with
this commit.

Also note that MODULE_ALIAS is a no-op for non-modular code.

We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.

We replace module.h with moduleparam.h since the file does actually
declare some module parameters (i.e. boot args for non-modules).

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-watchdog@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-05-05 21:10:33 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* coh901327_wdt.c
*
* Copyright (C) 2008-2009 ST-Ericsson AB
* Watchdog driver for the ST-Ericsson AB COH 901 327 IP core
* Author: Linus Walleij <linus.walleij@stericsson.com>
*/
#include <linux/moduleparam.h>
#include <linux/mod_devicetable.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/interrupt.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#define DRV_NAME "WDOG COH 901 327"
/*
* COH 901 327 register definitions
*/
/* WDOG_FEED Register 32bit (-/W) */
#define U300_WDOG_FR 0x00
#define U300_WDOG_FR_FEED_RESTART_TIMER 0xFEEDU
/* WDOG_TIMEOUT Register 32bit (R/W) */
#define U300_WDOG_TR 0x04
#define U300_WDOG_TR_TIMEOUT_MASK 0x7FFFU
/* WDOG_DISABLE1 Register 32bit (-/W) */
#define U300_WDOG_D1R 0x08
#define U300_WDOG_D1R_DISABLE1_DISABLE_TIMER 0x2BADU
/* WDOG_DISABLE2 Register 32bit (R/W) */
#define U300_WDOG_D2R 0x0C
#define U300_WDOG_D2R_DISABLE2_DISABLE_TIMER 0xCAFEU
#define U300_WDOG_D2R_DISABLE_STATUS_DISABLED 0xDABEU
#define U300_WDOG_D2R_DISABLE_STATUS_ENABLED 0x0000U
/* WDOG_STATUS Register 32bit (R/W) */
#define U300_WDOG_SR 0x10
#define U300_WDOG_SR_STATUS_TIMED_OUT 0xCFE8U
#define U300_WDOG_SR_STATUS_NORMAL 0x0000U
#define U300_WDOG_SR_RESET_STATUS_RESET 0xE8B4U
/* WDOG_COUNT Register 32bit (R/-) */
#define U300_WDOG_CR 0x14
#define U300_WDOG_CR_VALID_IND 0x8000U
#define U300_WDOG_CR_VALID_STABLE 0x0000U
#define U300_WDOG_CR_COUNT_VALUE_MASK 0x7FFFU
/* WDOG_JTAGOVR Register 32bit (R/W) */
#define U300_WDOG_JOR 0x18
#define U300_WDOG_JOR_JTAG_MODE_IND 0x0002U
#define U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE 0x0001U
/* WDOG_RESTART Register 32bit (-/W) */
#define U300_WDOG_RR 0x1C
#define U300_WDOG_RR_RESTART_VALUE_RESUME 0xACEDU
/* WDOG_IRQ_EVENT Register 32bit (R/W) */
#define U300_WDOG_IER 0x20
#define U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND 0x0001U
#define U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE 0x0001U
/* WDOG_IRQ_MASK Register 32bit (R/W) */
#define U300_WDOG_IMR 0x24
#define U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE 0x0001U
/* WDOG_IRQ_FORCE Register 32bit (R/W) */
#define U300_WDOG_IFR 0x28
#define U300_WDOG_IFR_WILL_BARK_IRQ_FORCE_ENABLE 0x0001U
/* Default timeout in seconds = 1 minute */
#define U300_WDOG_DEFAULT_TIMEOUT 60
static unsigned int margin;
static int irq;
static void __iomem *virtbase;
static struct device *parent;
static struct clk *clk;
/*
* Enabling and disabling functions.
*/
static void coh901327_enable(u16 timeout)
{
u16 val;
unsigned long freq;
unsigned long delay_ns;
/* Restart timer if it is disabled */
val = readw(virtbase + U300_WDOG_D2R);
if (val == U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
virtbase + U300_WDOG_RR);
/* Acknowledge any pending interrupt so it doesn't just fire off */
writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
virtbase + U300_WDOG_IER);
/*
* The interrupt is cleared in the 32 kHz clock domain.
* Wait 3 32 kHz cycles for it to take effect
*/
freq = clk_get_rate(clk);
delay_ns = DIV_ROUND_UP(1000000000, freq); /* Freq to ns and round up */
delay_ns = 3 * delay_ns; /* Wait 3 cycles */
ndelay(delay_ns);
/* Enable the watchdog interrupt */
writew(U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE, virtbase + U300_WDOG_IMR);
/* Activate the watchdog timer */
writew(timeout, virtbase + U300_WDOG_TR);
/* Start the watchdog timer */
writew(U300_WDOG_FR_FEED_RESTART_TIMER, virtbase + U300_WDOG_FR);
/*
* Extra read so that this change propagate in the watchdog.
*/
(void) readw(virtbase + U300_WDOG_CR);
val = readw(virtbase + U300_WDOG_D2R);
if (val != U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
dev_err(parent,
"%s(): watchdog not enabled! D2R value %04x\n",
__func__, val);
}
static void coh901327_disable(void)
{
u16 val;
/* Disable the watchdog interrupt if it is active */
writew(0x0000U, virtbase + U300_WDOG_IMR);
/* If the watchdog is currently enabled, attempt to disable it */
val = readw(virtbase + U300_WDOG_D2R);
if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED) {
writew(U300_WDOG_D1R_DISABLE1_DISABLE_TIMER,
virtbase + U300_WDOG_D1R);
writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
virtbase + U300_WDOG_D2R);
/* Write this twice (else problems occur) */
writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
virtbase + U300_WDOG_D2R);
}
val = readw(virtbase + U300_WDOG_D2R);
if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
dev_err(parent,
"%s(): watchdog not disabled! D2R value %04x\n",
__func__, val);
}
static int coh901327_start(struct watchdog_device *wdt_dev)
{
coh901327_enable(wdt_dev->timeout * 100);
return 0;
}
static int coh901327_stop(struct watchdog_device *wdt_dev)
{
coh901327_disable();
return 0;
}
static int coh901327_ping(struct watchdog_device *wdd)
{
/* Feed the watchdog */
writew(U300_WDOG_FR_FEED_RESTART_TIMER,
virtbase + U300_WDOG_FR);
return 0;
}
static int coh901327_settimeout(struct watchdog_device *wdt_dev,
unsigned int time)
{
wdt_dev->timeout = time;
/* Set new timeout value */
writew(time * 100, virtbase + U300_WDOG_TR);
/* Feed the dog */
writew(U300_WDOG_FR_FEED_RESTART_TIMER,
virtbase + U300_WDOG_FR);
return 0;
}
static unsigned int coh901327_gettimeleft(struct watchdog_device *wdt_dev)
{
u16 val;
/* Read repeatedly until the value is stable! */
val = readw(virtbase + U300_WDOG_CR);
while (val & U300_WDOG_CR_VALID_IND)
val = readw(virtbase + U300_WDOG_CR);
val &= U300_WDOG_CR_COUNT_VALUE_MASK;
if (val != 0)
val /= 100;
return val;
}
/*
* This interrupt occurs 10 ms before the watchdog WILL bark.
*/
static irqreturn_t coh901327_interrupt(int irq, void *data)
{
u16 val;
/*
* Ack IRQ? If this occurs we're FUBAR anyway, so
* just acknowledge, disable the interrupt and await the imminent end.
* If you at some point need a host of callbacks to be called
* when the system is about to watchdog-reset, add them here!
*
* NOTE: on future versions of this IP-block, it will be possible
* to prevent a watchdog reset by feeding the watchdog at this
* point.
*/
val = readw(virtbase + U300_WDOG_IER);
if (val == U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND)
writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
virtbase + U300_WDOG_IER);
writew(0x0000U, virtbase + U300_WDOG_IMR);
dev_crit(parent, "watchdog is barking!\n");
return IRQ_HANDLED;
}
static const struct watchdog_info coh901327_ident = {
.options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = DRV_NAME,
};
static const struct watchdog_ops coh901327_ops = {
.owner = THIS_MODULE,
.start = coh901327_start,
.stop = coh901327_stop,
.ping = coh901327_ping,
.set_timeout = coh901327_settimeout,
.get_timeleft = coh901327_gettimeleft,
};
static struct watchdog_device coh901327_wdt = {
.info = &coh901327_ident,
.ops = &coh901327_ops,
/*
* Max timeout is 327 since the 10ms
* timeout register is max
* 0x7FFF = 327670ms ~= 327s.
*/
.min_timeout = 1,
.max_timeout = 327,
.timeout = U300_WDOG_DEFAULT_TIMEOUT,
};
static int __init coh901327_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
int ret;
u16 val;
parent = dev;
virtbase = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(virtbase))
return PTR_ERR(virtbase);
clk = clk_get(dev, NULL);
if (IS_ERR(clk)) {
ret = PTR_ERR(clk);
dev_err(dev, "could not get clock\n");
return ret;
}
ret = clk_prepare_enable(clk);
if (ret) {
dev_err(dev, "could not prepare and enable clock\n");
goto out_no_clk_enable;
}
val = readw(virtbase + U300_WDOG_SR);
switch (val) {
case U300_WDOG_SR_STATUS_TIMED_OUT:
dev_info(dev, "watchdog timed out since last chip reset!\n");
coh901327_wdt.bootstatus |= WDIOF_CARDRESET;
/* Status will be cleared below */
break;
case U300_WDOG_SR_STATUS_NORMAL:
dev_info(dev, "in normal status, no timeouts have occurred.\n");
break;
default:
dev_info(dev, "contains an illegal status code (%08x)\n", val);
break;
}
val = readw(virtbase + U300_WDOG_D2R);
switch (val) {
case U300_WDOG_D2R_DISABLE_STATUS_DISABLED:
dev_info(dev, "currently disabled.\n");
break;
case U300_WDOG_D2R_DISABLE_STATUS_ENABLED:
dev_info(dev, "currently enabled! (disabling it now)\n");
coh901327_disable();
break;
default:
dev_err(dev, "contains an illegal enable/disable code (%08x)\n",
val);
break;
}
/* Reset the watchdog */
writew(U300_WDOG_SR_RESET_STATUS_RESET, virtbase + U300_WDOG_SR);
irq = platform_get_irq(pdev, 0);
if (request_irq(irq, coh901327_interrupt, 0,
DRV_NAME " Bark", pdev)) {
ret = -EIO;
goto out_no_irq;
}
watchdog_init_timeout(&coh901327_wdt, margin, dev);
coh901327_wdt.parent = dev;
ret = watchdog_register_device(&coh901327_wdt);
if (ret)
goto out_no_wdog;
dev_info(dev, "initialized. (timeout=%d sec)\n",
coh901327_wdt.timeout);
return 0;
out_no_wdog:
free_irq(irq, pdev);
out_no_irq:
clk_disable_unprepare(clk);
out_no_clk_enable:
clk_put(clk);
return ret;
}
#ifdef CONFIG_PM
static u16 wdogenablestore;
static u16 irqmaskstore;
static int coh901327_suspend(struct platform_device *pdev, pm_message_t state)
{
irqmaskstore = readw(virtbase + U300_WDOG_IMR) & 0x0001U;
wdogenablestore = readw(virtbase + U300_WDOG_D2R);
/* If watchdog is on, disable it here and now */
if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
coh901327_disable();
return 0;
}
static int coh901327_resume(struct platform_device *pdev)
{
/* Restore the watchdog interrupt */
writew(irqmaskstore, virtbase + U300_WDOG_IMR);
if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED) {
/* Restart the watchdog timer */
writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
virtbase + U300_WDOG_RR);
writew(U300_WDOG_FR_FEED_RESTART_TIMER,
virtbase + U300_WDOG_FR);
}
return 0;
}
#else
#define coh901327_suspend NULL
#define coh901327_resume NULL
#endif
/*
* Mistreating the watchdog is the only way to perform a software reset of the
* system on EMP platforms. So we implement this and export a symbol for it.
*/
void coh901327_watchdog_reset(void)
{
/* Enable even if on JTAG too */
writew(U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE,
virtbase + U300_WDOG_JOR);
/*
* Timeout = 5s, we have to wait for the watchdog reset to
* actually take place: the watchdog will be reloaded with the
* default value immediately, so we HAVE to reboot and get back
* into the kernel in 30s, or the device will reboot again!
* The boot loader will typically deactivate the watchdog, so we
* need time enough for the boot loader to get to the point of
* deactivating the watchdog before it is shut down by it.
*
* NOTE: on future versions of the watchdog, this restriction is
* gone: the watchdog will be reloaded with a default value (1 min)
* instead of last value, and you can conveniently set the watchdog
* timeout to 10ms (value = 1) without any problems.
*/
coh901327_enable(500);
/* Return and await doom */
}
static const struct of_device_id coh901327_dt_match[] = {
{ .compatible = "stericsson,coh901327" },
{},
};
static struct platform_driver coh901327_driver = {
.driver = {
.name = "coh901327_wdog",
.of_match_table = coh901327_dt_match,
.suppress_bind_attrs = true,
},
.suspend = coh901327_suspend,
.resume = coh901327_resume,
};
builtin_platform_driver_probe(coh901327_driver, coh901327_probe);
/* not really modular, but ... */
module_param(margin, uint, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
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