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linux_dsm_epyc7002/drivers/watchdog/kempld_wdt.c
Arnd Bergmann 3736d4eb6a watchdog: kempld: fix gcc-4.3 build 
gcc-4.3 can't decide whether the constant value in
kempld_prescaler[PRESCALER_21] is built-time constant or
not, and gets confused by the logic in do_div():

drivers/watchdog/kempld_wdt.o: In function `kempld_wdt_set_stage_timeout':
kempld_wdt.c:(.text.kempld_wdt_set_stage_timeout+0x130): undefined reference to `__aeabi_uldivmod'

This adds a call to ACCESS_ONCE() to force it to not consider
it to be constant, and leaves the more efficient normal case
in place for modern compilers, using an #ifdef to annotate
why we do this hack.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-03-01 06:15:10 -08:00

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/*
* Kontron PLD watchdog driver
*
* Copyright (c) 2010-2013 Kontron Europe GmbH
* Author: Michael Brunner <michael.brunner@kontron.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License 2 as published
* by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* Note: From the PLD watchdog point of view timeout and pretimeout are
* defined differently than in the kernel.
* First the pretimeout stage runs out before the timeout stage gets
* active.
*
* Kernel/API: P-----| pretimeout
* |-----------------------T timeout
* Watchdog: |-----------------P pretimeout_stage
* |-----T timeout_stage
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/uaccess.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/mfd/kempld.h>
#define KEMPLD_WDT_STAGE_TIMEOUT(x) (0x1b + (x) * 4)
#define KEMPLD_WDT_STAGE_CFG(x) (0x18 + (x))
#define STAGE_CFG_GET_PRESCALER(x) (((x) & 0x30) >> 4)
#define STAGE_CFG_SET_PRESCALER(x) (((x) & 0x3) << 4)
#define STAGE_CFG_PRESCALER_MASK 0x30
#define STAGE_CFG_ACTION_MASK 0x7
#define STAGE_CFG_ASSERT (1 << 3)
#define KEMPLD_WDT_MAX_STAGES 2
#define KEMPLD_WDT_KICK 0x16
#define KEMPLD_WDT_CFG 0x17
#define KEMPLD_WDT_CFG_ENABLE 0x10
#define KEMPLD_WDT_CFG_ENABLE_LOCK 0x8
#define KEMPLD_WDT_CFG_GLOBAL_LOCK 0x80
enum {
ACTION_NONE = 0,
ACTION_RESET,
ACTION_NMI,
ACTION_SMI,
ACTION_SCI,
ACTION_DELAY,
};
enum {
STAGE_TIMEOUT = 0,
STAGE_PRETIMEOUT,
};
enum {
PRESCALER_21 = 0,
PRESCALER_17,
PRESCALER_12,
};
static const u32 kempld_prescaler[] = {
[PRESCALER_21] = (1 << 21) - 1,
[PRESCALER_17] = (1 << 17) - 1,
[PRESCALER_12] = (1 << 12) - 1,
0,
};
struct kempld_wdt_stage {
unsigned int id;
u32 mask;
};
struct kempld_wdt_data {
struct kempld_device_data *pld;
struct watchdog_device wdd;
unsigned int pretimeout;
struct kempld_wdt_stage stage[KEMPLD_WDT_MAX_STAGES];
#ifdef CONFIG_PM
u8 pm_status_store;
#endif
};
#define DEFAULT_TIMEOUT 30 /* seconds */
#define DEFAULT_PRETIMEOUT 0
static unsigned int timeout = DEFAULT_TIMEOUT;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. (>=0, default="
__MODULE_STRING(DEFAULT_TIMEOUT) ")");
static unsigned int pretimeout = DEFAULT_PRETIMEOUT;
module_param(pretimeout, uint, 0);
MODULE_PARM_DESC(pretimeout,
"Watchdog pretimeout in seconds. (>=0, default="
__MODULE_STRING(DEFAULT_PRETIMEOUT) ")");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static int kempld_wdt_set_stage_action(struct kempld_wdt_data *wdt_data,
struct kempld_wdt_stage *stage,
u8 action)
{
struct kempld_device_data *pld = wdt_data->pld;
u8 stage_cfg;
if (!stage || !stage->mask)
return -EINVAL;
kempld_get_mutex(pld);
stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
stage_cfg &= ~STAGE_CFG_ACTION_MASK;
stage_cfg |= (action & STAGE_CFG_ACTION_MASK);
if (action == ACTION_RESET)
stage_cfg |= STAGE_CFG_ASSERT;
else
stage_cfg &= ~STAGE_CFG_ASSERT;
kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg);
kempld_release_mutex(pld);
return 0;
}
static int kempld_wdt_set_stage_timeout(struct kempld_wdt_data *wdt_data,
struct kempld_wdt_stage *stage,
unsigned int timeout)
{
struct kempld_device_data *pld = wdt_data->pld;
u32 prescaler;
u64 stage_timeout64;
u32 stage_timeout;
u32 remainder;
u8 stage_cfg;
#if GCC_VERSION < 40400
/* work around a bug compiling do_div() */
prescaler = READ_ONCE(kempld_prescaler[PRESCALER_21]);
#else
prescaler = kempld_prescaler[PRESCALER_21];
#endif
if (!stage)
return -EINVAL;
stage_timeout64 = (u64)timeout * pld->pld_clock;
remainder = do_div(stage_timeout64, prescaler);
if (remainder)
stage_timeout64++;
if (stage_timeout64 > stage->mask)
return -EINVAL;
stage_timeout = stage_timeout64 & stage->mask;
kempld_get_mutex(pld);
stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
stage_cfg &= ~STAGE_CFG_PRESCALER_MASK;
stage_cfg |= STAGE_CFG_SET_PRESCALER(PRESCALER_21);
kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg);
kempld_write32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id),
stage_timeout);
kempld_release_mutex(pld);
return 0;
}
/*
* kempld_get_mutex must be called prior to calling this function.
*/
static unsigned int kempld_wdt_get_timeout(struct kempld_wdt_data *wdt_data,
struct kempld_wdt_stage *stage)
{
struct kempld_device_data *pld = wdt_data->pld;
unsigned int timeout;
u64 stage_timeout;
u32 prescaler;
u32 remainder;
u8 stage_cfg;
if (!stage->mask)
return 0;
stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
stage_timeout = kempld_read32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id));
prescaler = kempld_prescaler[STAGE_CFG_GET_PRESCALER(stage_cfg)];
stage_timeout = (stage_timeout & stage->mask) * prescaler;
remainder = do_div(stage_timeout, pld->pld_clock);
if (remainder)
stage_timeout++;
timeout = stage_timeout;
WARN_ON_ONCE(timeout != stage_timeout);
return timeout;
}
static int kempld_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
struct kempld_wdt_stage *pretimeout_stage;
struct kempld_wdt_stage *timeout_stage;
int ret;
timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
if (pretimeout_stage->mask && wdt_data->pretimeout > 0)
timeout = wdt_data->pretimeout;
ret = kempld_wdt_set_stage_action(wdt_data, timeout_stage,
ACTION_RESET);
if (ret)
return ret;
ret = kempld_wdt_set_stage_timeout(wdt_data, timeout_stage,
timeout);
if (ret)
return ret;
wdd->timeout = timeout;
return 0;
}
static int kempld_wdt_set_pretimeout(struct watchdog_device *wdd,
unsigned int pretimeout)
{
struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
struct kempld_wdt_stage *pretimeout_stage;
u8 action = ACTION_NONE;
int ret;
pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
if (!pretimeout_stage->mask)
return -ENXIO;
if (pretimeout > wdd->timeout)
return -EINVAL;
if (pretimeout > 0)
action = ACTION_NMI;
ret = kempld_wdt_set_stage_action(wdt_data, pretimeout_stage,
action);
if (ret)
return ret;
ret = kempld_wdt_set_stage_timeout(wdt_data, pretimeout_stage,
wdd->timeout - pretimeout);
if (ret)
return ret;
wdt_data->pretimeout = pretimeout;
return 0;
}
static void kempld_wdt_update_timeouts(struct kempld_wdt_data *wdt_data)
{
struct kempld_device_data *pld = wdt_data->pld;
struct kempld_wdt_stage *pretimeout_stage;
struct kempld_wdt_stage *timeout_stage;
unsigned int pretimeout, timeout;
pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
kempld_get_mutex(pld);
pretimeout = kempld_wdt_get_timeout(wdt_data, pretimeout_stage);
timeout = kempld_wdt_get_timeout(wdt_data, timeout_stage);
kempld_release_mutex(pld);
if (pretimeout)
wdt_data->pretimeout = timeout;
else
wdt_data->pretimeout = 0;
wdt_data->wdd.timeout = pretimeout + timeout;
}
static int kempld_wdt_start(struct watchdog_device *wdd)
{
struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
struct kempld_device_data *pld = wdt_data->pld;
u8 status;
int ret;
ret = kempld_wdt_set_timeout(wdd, wdd->timeout);
if (ret)
return ret;
kempld_get_mutex(pld);
status = kempld_read8(pld, KEMPLD_WDT_CFG);
status |= KEMPLD_WDT_CFG_ENABLE;
kempld_write8(pld, KEMPLD_WDT_CFG, status);
status = kempld_read8(pld, KEMPLD_WDT_CFG);
kempld_release_mutex(pld);
/* Check if the watchdog was enabled */
if (!(status & KEMPLD_WDT_CFG_ENABLE))
return -EACCES;
return 0;
}
static int kempld_wdt_stop(struct watchdog_device *wdd)
{
struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
struct kempld_device_data *pld = wdt_data->pld;
u8 status;
kempld_get_mutex(pld);
status = kempld_read8(pld, KEMPLD_WDT_CFG);
status &= ~KEMPLD_WDT_CFG_ENABLE;
kempld_write8(pld, KEMPLD_WDT_CFG, status);
status = kempld_read8(pld, KEMPLD_WDT_CFG);
kempld_release_mutex(pld);
/* Check if the watchdog was disabled */
if (status & KEMPLD_WDT_CFG_ENABLE)
return -EACCES;
return 0;
}
static int kempld_wdt_keepalive(struct watchdog_device *wdd)
{
struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
struct kempld_device_data *pld = wdt_data->pld;
kempld_get_mutex(pld);
kempld_write8(pld, KEMPLD_WDT_KICK, 'K');
kempld_release_mutex(pld);
return 0;
}
static long kempld_wdt_ioctl(struct watchdog_device *wdd, unsigned int cmd,
unsigned long arg)
{
struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
void __user *argp = (void __user *)arg;
int ret = -ENOIOCTLCMD;
int __user *p = argp;
int new_value;
switch (cmd) {
case WDIOC_SETPRETIMEOUT:
if (get_user(new_value, p))
return -EFAULT;
ret = kempld_wdt_set_pretimeout(wdd, new_value);
if (ret)
return ret;
ret = kempld_wdt_keepalive(wdd);
break;
case WDIOC_GETPRETIMEOUT:
ret = put_user(wdt_data->pretimeout, (int __user *)arg);
break;
}
return ret;
}
static int kempld_wdt_probe_stages(struct watchdog_device *wdd)
{
struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
struct kempld_device_data *pld = wdt_data->pld;
struct kempld_wdt_stage *pretimeout_stage;
struct kempld_wdt_stage *timeout_stage;
u8 index, data, data_orig;
u32 mask;
int i, j;
pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
pretimeout_stage->mask = 0;
timeout_stage->mask = 0;
for (i = 0; i < 3; i++) {
index = KEMPLD_WDT_STAGE_TIMEOUT(i);
mask = 0;
kempld_get_mutex(pld);
/* Probe each byte individually. */
for (j = 0; j < 4; j++) {
data_orig = kempld_read8(pld, index + j);
kempld_write8(pld, index + j, 0x00);
data = kempld_read8(pld, index + j);
/* A failed write means this byte is reserved */
if (data != 0x00)
break;
kempld_write8(pld, index + j, data_orig);
mask |= 0xff << (j * 8);
}
kempld_release_mutex(pld);
/* Assign available stages to timeout and pretimeout */
if (!timeout_stage->mask) {
timeout_stage->mask = mask;
timeout_stage->id = i;
} else {
if (pld->feature_mask & KEMPLD_FEATURE_BIT_NMI) {
pretimeout_stage->mask = timeout_stage->mask;
timeout_stage->mask = mask;
pretimeout_stage->id = timeout_stage->id;
timeout_stage->id = i;
}
break;
}
}
if (!timeout_stage->mask)
return -ENODEV;
return 0;
}
static const struct watchdog_info kempld_wdt_info = {
.identity = "KEMPLD Watchdog",
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE |
WDIOF_PRETIMEOUT
};
static const struct watchdog_ops kempld_wdt_ops = {
.owner = THIS_MODULE,
.start = kempld_wdt_start,
.stop = kempld_wdt_stop,
.ping = kempld_wdt_keepalive,
.set_timeout = kempld_wdt_set_timeout,
.ioctl = kempld_wdt_ioctl,
};
static int kempld_wdt_probe(struct platform_device *pdev)
{
struct kempld_device_data *pld = dev_get_drvdata(pdev->dev.parent);
struct kempld_wdt_data *wdt_data;
struct device *dev = &pdev->dev;
struct watchdog_device *wdd;
u8 status;
int ret = 0;
wdt_data = devm_kzalloc(dev, sizeof(*wdt_data), GFP_KERNEL);
if (!wdt_data)
return -ENOMEM;
wdt_data->pld = pld;
wdd = &wdt_data->wdd;
wdd->parent = dev;
kempld_get_mutex(pld);
status = kempld_read8(pld, KEMPLD_WDT_CFG);
kempld_release_mutex(pld);
/* Enable nowayout if watchdog is already locked */
if (status & (KEMPLD_WDT_CFG_ENABLE_LOCK |
KEMPLD_WDT_CFG_GLOBAL_LOCK)) {
if (!nowayout)
dev_warn(dev,
"Forcing nowayout - watchdog lock enabled!\n");
nowayout = true;
}
wdd->info = &kempld_wdt_info;
wdd->ops = &kempld_wdt_ops;
watchdog_set_drvdata(wdd, wdt_data);
watchdog_set_nowayout(wdd, nowayout);
ret = kempld_wdt_probe_stages(wdd);
if (ret)
return ret;
kempld_wdt_set_timeout(wdd, timeout);
kempld_wdt_set_pretimeout(wdd, pretimeout);
/* Check if watchdog is already enabled */
if (status & KEMPLD_WDT_CFG_ENABLE) {
/* Get current watchdog settings */
kempld_wdt_update_timeouts(wdt_data);
dev_info(dev, "Watchdog was already enabled\n");
}
platform_set_drvdata(pdev, wdt_data);
ret = watchdog_register_device(wdd);
if (ret)
return ret;
dev_info(dev, "Watchdog registered with %ds timeout\n", wdd->timeout);
return 0;
}
static void kempld_wdt_shutdown(struct platform_device *pdev)
{
struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
kempld_wdt_stop(&wdt_data->wdd);
}
static int kempld_wdt_remove(struct platform_device *pdev)
{
struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
struct watchdog_device *wdd = &wdt_data->wdd;
int ret = 0;
if (!nowayout)
ret = kempld_wdt_stop(wdd);
watchdog_unregister_device(wdd);
return ret;
}
#ifdef CONFIG_PM
/* Disable watchdog if it is active during suspend */
static int kempld_wdt_suspend(struct platform_device *pdev,
pm_message_t message)
{
struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
struct kempld_device_data *pld = wdt_data->pld;
struct watchdog_device *wdd = &wdt_data->wdd;
kempld_get_mutex(pld);
wdt_data->pm_status_store = kempld_read8(pld, KEMPLD_WDT_CFG);
kempld_release_mutex(pld);
kempld_wdt_update_timeouts(wdt_data);
if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE)
return kempld_wdt_stop(wdd);
return 0;
}
/* Enable watchdog and configure it if necessary */
static int kempld_wdt_resume(struct platform_device *pdev)
{
struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
struct watchdog_device *wdd = &wdt_data->wdd;
/*
* If watchdog was stopped before suspend be sure it gets disabled
* again, for the case BIOS has enabled it during resume
*/
if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE)
return kempld_wdt_start(wdd);
else
return kempld_wdt_stop(wdd);
}
#else
#define kempld_wdt_suspend NULL
#define kempld_wdt_resume NULL
#endif
static struct platform_driver kempld_wdt_driver = {
.driver = {
.name = "kempld-wdt",
},
.probe = kempld_wdt_probe,
.remove = kempld_wdt_remove,
.shutdown = kempld_wdt_shutdown,
.suspend = kempld_wdt_suspend,
.resume = kempld_wdt_resume,
};
module_platform_driver(kempld_wdt_driver);
MODULE_DESCRIPTION("KEM PLD Watchdog Driver");
MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
MODULE_LICENSE("GPL");
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