linux/drivers/watchdog/sbsa_gwdt.c
Darren Hart 5d6aa89bba sbsa_gwdt: Calculate timeout with 64-bit math
Commit abd3ac7902 ("watchdog: sbsa: Support architecture version 1")
introduced new timer math for watchdog revision 1 with the 48 bit offset
register.

The gwdt->clk and timeout are u32, but the argument being calculated is
u64. Without a cast, the compiler performs u32 operations, truncating
intermediate steps, resulting in incorrect values.

A watchdog revision 1 implementation with a gwdt->clk of 1GHz and a
timeout of 600s writes 3647256576 to the one shot watchdog instead of
300000000000, resulting in the watchdog firing in 3.6s instead of 600s.

Force u64 math by casting the first argument (gwdt->clk) as a u64. Make
the order of operations explicit with parenthesis.

Fixes: abd3ac7902 ("watchdog: sbsa: Support architecture version 1")
Reported-by: Vanshidhar Konda <vanshikonda@os.amperecomputing.com>
Signed-off-by: Darren Hart <darren@os.amperecomputing.com>
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-watchdog@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: <stable@vger.kernel.org> # 5.14.x
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/7d1713c5ffab19b0f3de796d82df19e8b1f340de.1695286124.git.darren@os.amperecomputing.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2023-10-29 19:45:05 +01:00

414 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* SBSA(Server Base System Architecture) Generic Watchdog driver
*
* Copyright (c) 2015, Linaro Ltd.
* Author: Fu Wei <fu.wei@linaro.org>
* Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
* Al Stone <al.stone@linaro.org>
* Timur Tabi <timur@codeaurora.org>
*
* ARM SBSA Generic Watchdog has two stage timeouts:
* the first signal (WS0) is for alerting the system by interrupt,
* the second one (WS1) is a real hardware reset.
* More details about the hardware specification of this device:
* ARM DEN0029B - Server Base System Architecture (SBSA)
*
* This driver can operate ARM SBSA Generic Watchdog as a single stage watchdog
* or a two stages watchdog, it's set up by the module parameter "action".
* In the single stage mode, when the timeout is reached, your system
* will be reset by WS1. The first signal (WS0) is ignored.
* In the two stages mode, when the timeout is reached, the first signal (WS0)
* will trigger panic. If the system is getting into trouble and cannot be reset
* by panic or restart properly by the kdump kernel(if supported), then the
* second stage (as long as the first stage) will be reached, system will be
* reset by WS1. This function can help administrator to backup the system
* context info by panic console output or kdump.
*
* SBSA GWDT:
* if action is 1 (the two stages mode):
* |--------WOR-------WS0--------WOR-------WS1
* |----timeout-----(panic)----timeout-----reset
*
* if action is 0 (the single stage mode):
* |------WOR-----WS0(ignored)-----WOR------WS1
* |--------------timeout-------------------reset
*
* Note: Since this watchdog timer has two stages, and each stage is determined
* by WOR, in the single stage mode, the timeout is (WOR * 2); in the two
* stages mode, the timeout is WOR. The maximum timeout in the two stages mode
* is half of that in the single stage mode.
*/
#include <linux/io.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/interrupt.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/uaccess.h>
#include <linux/watchdog.h>
#include <asm/arch_timer.h>
#define DRV_NAME "sbsa-gwdt"
#define WATCHDOG_NAME "SBSA Generic Watchdog"
/* SBSA Generic Watchdog register definitions */
/* refresh frame */
#define SBSA_GWDT_WRR 0x000
/* control frame */
#define SBSA_GWDT_WCS 0x000
#define SBSA_GWDT_WOR 0x008
#define SBSA_GWDT_WCV 0x010
/* refresh/control frame */
#define SBSA_GWDT_W_IIDR 0xfcc
#define SBSA_GWDT_IDR 0xfd0
/* Watchdog Control and Status Register */
#define SBSA_GWDT_WCS_EN BIT(0)
#define SBSA_GWDT_WCS_WS0 BIT(1)
#define SBSA_GWDT_WCS_WS1 BIT(2)
#define SBSA_GWDT_VERSION_MASK 0xF
#define SBSA_GWDT_VERSION_SHIFT 16
/**
* struct sbsa_gwdt - Internal representation of the SBSA GWDT
* @wdd: kernel watchdog_device structure
* @clk: store the System Counter clock frequency, in Hz.
* @version: store the architecture version
* @refresh_base: Virtual address of the watchdog refresh frame
* @control_base: Virtual address of the watchdog control frame
*/
struct sbsa_gwdt {
struct watchdog_device wdd;
u32 clk;
int version;
void __iomem *refresh_base;
void __iomem *control_base;
};
#define DEFAULT_TIMEOUT 10 /* seconds */
static unsigned int timeout;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. (>=0, default="
__MODULE_STRING(DEFAULT_TIMEOUT) ")");
/*
* action refers to action taken when watchdog gets WS0
* 0 = skip
* 1 = panic
* defaults to skip (0)
*/
static int action;
module_param(action, int, 0);
MODULE_PARM_DESC(action, "after watchdog gets WS0 interrupt, do: "
"0 = skip(*) 1 = panic");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, S_IRUGO);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
/*
* Arm Base System Architecture 1.0 introduces watchdog v1 which
* increases the length watchdog offset register to 48 bits.
* - For version 0: WOR is 32 bits;
* - For version 1: WOR is 48 bits which comprises the register
* offset 0x8 and 0xC, and the bits [63:48] are reserved which are
* Read-As-Zero and Writes-Ignored.
*/
static u64 sbsa_gwdt_reg_read(struct sbsa_gwdt *gwdt)
{
if (gwdt->version == 0)
return readl(gwdt->control_base + SBSA_GWDT_WOR);
else
return lo_hi_readq(gwdt->control_base + SBSA_GWDT_WOR);
}
static void sbsa_gwdt_reg_write(u64 val, struct sbsa_gwdt *gwdt)
{
if (gwdt->version == 0)
writel((u32)val, gwdt->control_base + SBSA_GWDT_WOR);
else
lo_hi_writeq(val, gwdt->control_base + SBSA_GWDT_WOR);
}
/*
* watchdog operation functions
*/
static int sbsa_gwdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
struct sbsa_gwdt *gwdt = watchdog_get_drvdata(wdd);
wdd->timeout = timeout;
timeout = clamp_t(unsigned int, timeout, 1, wdd->max_hw_heartbeat_ms / 1000);
if (action)
sbsa_gwdt_reg_write((u64)gwdt->clk * timeout, gwdt);
else
/*
* In the single stage mode, The first signal (WS0) is ignored,
* the timeout is (WOR * 2), so the WOR should be configured
* to half value of timeout.
*/
sbsa_gwdt_reg_write(((u64)gwdt->clk / 2) * timeout, gwdt);
return 0;
}
static unsigned int sbsa_gwdt_get_timeleft(struct watchdog_device *wdd)
{
struct sbsa_gwdt *gwdt = watchdog_get_drvdata(wdd);
u64 timeleft = 0;
/*
* In the single stage mode, if WS0 is deasserted
* (watchdog is in the first stage),
* timeleft = WOR + (WCV - system counter)
*/
if (!action &&
!(readl(gwdt->control_base + SBSA_GWDT_WCS) & SBSA_GWDT_WCS_WS0))
timeleft += sbsa_gwdt_reg_read(gwdt);
timeleft += lo_hi_readq(gwdt->control_base + SBSA_GWDT_WCV) -
arch_timer_read_counter();
do_div(timeleft, gwdt->clk);
return timeleft;
}
static int sbsa_gwdt_keepalive(struct watchdog_device *wdd)
{
struct sbsa_gwdt *gwdt = watchdog_get_drvdata(wdd);
/*
* Writing WRR for an explicit watchdog refresh.
* You can write anyting (like 0).
*/
writel(0, gwdt->refresh_base + SBSA_GWDT_WRR);
return 0;
}
static void sbsa_gwdt_get_version(struct watchdog_device *wdd)
{
struct sbsa_gwdt *gwdt = watchdog_get_drvdata(wdd);
int ver;
ver = readl(gwdt->control_base + SBSA_GWDT_W_IIDR);
ver = (ver >> SBSA_GWDT_VERSION_SHIFT) & SBSA_GWDT_VERSION_MASK;
gwdt->version = ver;
}
static int sbsa_gwdt_start(struct watchdog_device *wdd)
{
struct sbsa_gwdt *gwdt = watchdog_get_drvdata(wdd);
/* writing WCS will cause an explicit watchdog refresh */
writel(SBSA_GWDT_WCS_EN, gwdt->control_base + SBSA_GWDT_WCS);
return 0;
}
static int sbsa_gwdt_stop(struct watchdog_device *wdd)
{
struct sbsa_gwdt *gwdt = watchdog_get_drvdata(wdd);
/* Simply write 0 to WCS to clean WCS_EN bit */
writel(0, gwdt->control_base + SBSA_GWDT_WCS);
return 0;
}
static irqreturn_t sbsa_gwdt_interrupt(int irq, void *dev_id)
{
panic(WATCHDOG_NAME " timeout");
return IRQ_HANDLED;
}
static const struct watchdog_info sbsa_gwdt_info = {
.identity = WATCHDOG_NAME,
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE |
WDIOF_CARDRESET,
};
static const struct watchdog_ops sbsa_gwdt_ops = {
.owner = THIS_MODULE,
.start = sbsa_gwdt_start,
.stop = sbsa_gwdt_stop,
.ping = sbsa_gwdt_keepalive,
.set_timeout = sbsa_gwdt_set_timeout,
.get_timeleft = sbsa_gwdt_get_timeleft,
};
static int sbsa_gwdt_probe(struct platform_device *pdev)
{
void __iomem *rf_base, *cf_base;
struct device *dev = &pdev->dev;
struct watchdog_device *wdd;
struct sbsa_gwdt *gwdt;
int ret, irq;
u32 status;
gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
if (!gwdt)
return -ENOMEM;
platform_set_drvdata(pdev, gwdt);
cf_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(cf_base))
return PTR_ERR(cf_base);
rf_base = devm_platform_ioremap_resource(pdev, 1);
if (IS_ERR(rf_base))
return PTR_ERR(rf_base);
/*
* Get the frequency of system counter from the cp15 interface of ARM
* Generic timer. We don't need to check it, because if it returns "0",
* system would panic in very early stage.
*/
gwdt->clk = arch_timer_get_cntfrq();
gwdt->refresh_base = rf_base;
gwdt->control_base = cf_base;
wdd = &gwdt->wdd;
wdd->parent = dev;
wdd->info = &sbsa_gwdt_info;
wdd->ops = &sbsa_gwdt_ops;
wdd->min_timeout = 1;
wdd->timeout = DEFAULT_TIMEOUT;
watchdog_set_drvdata(wdd, gwdt);
watchdog_set_nowayout(wdd, nowayout);
sbsa_gwdt_get_version(wdd);
if (gwdt->version == 0)
wdd->max_hw_heartbeat_ms = U32_MAX / gwdt->clk * 1000;
else
wdd->max_hw_heartbeat_ms = GENMASK_ULL(47, 0) / gwdt->clk * 1000;
status = readl(cf_base + SBSA_GWDT_WCS);
if (status & SBSA_GWDT_WCS_WS1) {
dev_warn(dev, "System reset by WDT.\n");
wdd->bootstatus |= WDIOF_CARDRESET;
}
if (status & SBSA_GWDT_WCS_EN)
set_bit(WDOG_HW_RUNNING, &wdd->status);
if (action) {
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
action = 0;
dev_warn(dev, "unable to get ws0 interrupt.\n");
} else {
/*
* In case there is a pending ws0 interrupt, just ping
* the watchdog before registering the interrupt routine
*/
writel(0, rf_base + SBSA_GWDT_WRR);
if (devm_request_irq(dev, irq, sbsa_gwdt_interrupt, 0,
pdev->name, gwdt)) {
action = 0;
dev_warn(dev, "unable to request IRQ %d.\n",
irq);
}
}
if (!action)
dev_warn(dev, "falling back to single stage mode.\n");
}
/*
* In the single stage mode, The first signal (WS0) is ignored,
* the timeout is (WOR * 2), so the maximum timeout should be doubled.
*/
if (!action)
wdd->max_hw_heartbeat_ms *= 2;
watchdog_init_timeout(wdd, timeout, dev);
/*
* Update timeout to WOR.
* Because of the explicit watchdog refresh mechanism,
* it's also a ping, if watchdog is enabled.
*/
sbsa_gwdt_set_timeout(wdd, wdd->timeout);
watchdog_stop_on_reboot(wdd);
ret = devm_watchdog_register_device(dev, wdd);
if (ret)
return ret;
dev_info(dev, "Initialized with %ds timeout @ %u Hz, action=%d.%s\n",
wdd->timeout, gwdt->clk, action,
status & SBSA_GWDT_WCS_EN ? " [enabled]" : "");
return 0;
}
/* Disable watchdog if it is active during suspend */
static int __maybe_unused sbsa_gwdt_suspend(struct device *dev)
{
struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);
if (watchdog_hw_running(&gwdt->wdd))
sbsa_gwdt_stop(&gwdt->wdd);
return 0;
}
/* Enable watchdog if necessary */
static int __maybe_unused sbsa_gwdt_resume(struct device *dev)
{
struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);
if (watchdog_hw_running(&gwdt->wdd))
sbsa_gwdt_start(&gwdt->wdd);
return 0;
}
static const struct dev_pm_ops sbsa_gwdt_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(sbsa_gwdt_suspend, sbsa_gwdt_resume)
};
static const struct of_device_id sbsa_gwdt_of_match[] = {
{ .compatible = "arm,sbsa-gwdt", },
{},
};
MODULE_DEVICE_TABLE(of, sbsa_gwdt_of_match);
static const struct platform_device_id sbsa_gwdt_pdev_match[] = {
{ .name = DRV_NAME, },
{},
};
MODULE_DEVICE_TABLE(platform, sbsa_gwdt_pdev_match);
static struct platform_driver sbsa_gwdt_driver = {
.driver = {
.name = DRV_NAME,
.pm = &sbsa_gwdt_pm_ops,
.of_match_table = sbsa_gwdt_of_match,
},
.probe = sbsa_gwdt_probe,
.id_table = sbsa_gwdt_pdev_match,
};
module_platform_driver(sbsa_gwdt_driver);
MODULE_DESCRIPTION("SBSA Generic Watchdog Driver");
MODULE_AUTHOR("Fu Wei <fu.wei@linaro.org>");
MODULE_AUTHOR("Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>");
MODULE_AUTHOR("Al Stone <al.stone@linaro.org>");
MODULE_AUTHOR("Timur Tabi <timur@codeaurora.org>");
MODULE_LICENSE("GPL v2");