swh:1:snp:c3bf2749e3476071fa748f67b0ffa2fdc5fe49d9
Tip revision: f40ddce88593482919761f74910f42f4b84c004b authored by Linus Torvalds on 14 February 2021, 22:32:24 UTC
Linux 5.11
Linux 5.11
Tip revision: f40ddce
aspeed_wdt.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2016 IBM Corporation
*
* Joel Stanley <joel@jms.id.au>
*/
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
struct aspeed_wdt {
struct watchdog_device wdd;
void __iomem *base;
u32 ctrl;
};
struct aspeed_wdt_config {
u32 ext_pulse_width_mask;
};
static const struct aspeed_wdt_config ast2400_config = {
.ext_pulse_width_mask = 0xff,
};
static const struct aspeed_wdt_config ast2500_config = {
.ext_pulse_width_mask = 0xfffff,
};
static const struct of_device_id aspeed_wdt_of_table[] = {
{ .compatible = "aspeed,ast2400-wdt", .data = &ast2400_config },
{ .compatible = "aspeed,ast2500-wdt", .data = &ast2500_config },
{ .compatible = "aspeed,ast2600-wdt", .data = &ast2500_config },
{ },
};
MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
#define WDT_STATUS 0x00
#define WDT_RELOAD_VALUE 0x04
#define WDT_RESTART 0x08
#define WDT_CTRL 0x0C
#define WDT_CTRL_BOOT_SECONDARY BIT(7)
#define WDT_CTRL_RESET_MODE_SOC (0x00 << 5)
#define WDT_CTRL_RESET_MODE_FULL_CHIP (0x01 << 5)
#define WDT_CTRL_RESET_MODE_ARM_CPU (0x10 << 5)
#define WDT_CTRL_1MHZ_CLK BIT(4)
#define WDT_CTRL_WDT_EXT BIT(3)
#define WDT_CTRL_WDT_INTR BIT(2)
#define WDT_CTRL_RESET_SYSTEM BIT(1)
#define WDT_CTRL_ENABLE BIT(0)
#define WDT_TIMEOUT_STATUS 0x10
#define WDT_TIMEOUT_STATUS_BOOT_SECONDARY BIT(1)
#define WDT_CLEAR_TIMEOUT_STATUS 0x14
#define WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION BIT(0)
/*
* WDT_RESET_WIDTH controls the characteristics of the external pulse (if
* enabled), specifically:
*
* * Pulse duration
* * Drive mode: push-pull vs open-drain
* * Polarity: Active high or active low
*
* Pulse duration configuration is available on both the AST2400 and AST2500,
* though the field changes between SoCs:
*
* AST2400: Bits 7:0
* AST2500: Bits 19:0
*
* This difference is captured in struct aspeed_wdt_config.
*
* The AST2500 exposes the drive mode and polarity options, but not in a
* regular fashion. For read purposes, bit 31 represents active high or low,
* and bit 30 represents push-pull or open-drain. With respect to write, magic
* values need to be written to the top byte to change the state of the drive
* mode and polarity bits. Any other value written to the top byte has no
* effect on the state of the drive mode or polarity bits. However, the pulse
* width value must be preserved (as desired) if written.
*/
#define WDT_RESET_WIDTH 0x18
#define WDT_RESET_WIDTH_ACTIVE_HIGH BIT(31)
#define WDT_ACTIVE_HIGH_MAGIC (0xA5 << 24)
#define WDT_ACTIVE_LOW_MAGIC (0x5A << 24)
#define WDT_RESET_WIDTH_PUSH_PULL BIT(30)
#define WDT_PUSH_PULL_MAGIC (0xA8 << 24)
#define WDT_OPEN_DRAIN_MAGIC (0x8A << 24)
#define WDT_RESTART_MAGIC 0x4755
/* 32 bits at 1MHz, in milliseconds */
#define WDT_MAX_TIMEOUT_MS 4294967
#define WDT_DEFAULT_TIMEOUT 30
#define WDT_RATE_1MHZ 1000000
static struct aspeed_wdt *to_aspeed_wdt(struct watchdog_device *wdd)
{
return container_of(wdd, struct aspeed_wdt, wdd);
}
static void aspeed_wdt_enable(struct aspeed_wdt *wdt, int count)
{
wdt->ctrl |= WDT_CTRL_ENABLE;
writel(0, wdt->base + WDT_CTRL);
writel(count, wdt->base + WDT_RELOAD_VALUE);
writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
writel(wdt->ctrl, wdt->base + WDT_CTRL);
}
static int aspeed_wdt_start(struct watchdog_device *wdd)
{
struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
aspeed_wdt_enable(wdt, wdd->timeout * WDT_RATE_1MHZ);
return 0;
}
static int aspeed_wdt_stop(struct watchdog_device *wdd)
{
struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
wdt->ctrl &= ~WDT_CTRL_ENABLE;
writel(wdt->ctrl, wdt->base + WDT_CTRL);
return 0;
}
static int aspeed_wdt_ping(struct watchdog_device *wdd)
{
struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
return 0;
}
static int aspeed_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
u32 actual;
wdd->timeout = timeout;
actual = min(timeout, wdd->max_hw_heartbeat_ms * 1000);
writel(actual * WDT_RATE_1MHZ, wdt->base + WDT_RELOAD_VALUE);
writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
return 0;
}
static int aspeed_wdt_restart(struct watchdog_device *wdd,
unsigned long action, void *data)
{
struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
wdt->ctrl &= ~WDT_CTRL_BOOT_SECONDARY;
aspeed_wdt_enable(wdt, 128 * WDT_RATE_1MHZ / 1000);
mdelay(1000);
return 0;
}
/* access_cs0 shows if cs0 is accessible, hence the reverted bit */
static ssize_t access_cs0_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct aspeed_wdt *wdt = dev_get_drvdata(dev);
u32 status = readl(wdt->base + WDT_TIMEOUT_STATUS);
return sprintf(buf, "%u\n",
!(status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY));
}
static ssize_t access_cs0_store(struct device *dev,
struct device_attribute *attr, const char *buf,
size_t size)
{
struct aspeed_wdt *wdt = dev_get_drvdata(dev);
unsigned long val;
if (kstrtoul(buf, 10, &val))
return -EINVAL;
if (val)
writel(WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION,
wdt->base + WDT_CLEAR_TIMEOUT_STATUS);
return size;
}
/*
* This attribute exists only if the system has booted from the alternate
* flash with 'alt-boot' option.
*
* At alternate flash the 'access_cs0' sysfs node provides:
* ast2400: a way to get access to the primary SPI flash chip at CS0
* after booting from the alternate chip at CS1.
* ast2500: a way to restore the normal address mapping from
* (CS0->CS1, CS1->CS0) to (CS0->CS0, CS1->CS1).
*
* Clearing the boot code selection and timeout counter also resets to the
* initial state the chip select line mapping. When the SoC is in normal
* mapping state (i.e. booted from CS0), clearing those bits does nothing for
* both versions of the SoC. For alternate boot mode (booted from CS1 due to
* wdt2 expiration) the behavior differs as described above.
*
* This option can be used with wdt2 (watchdog1) only.
*/
static DEVICE_ATTR_RW(access_cs0);
static struct attribute *bswitch_attrs[] = {
&dev_attr_access_cs0.attr,
NULL
};
ATTRIBUTE_GROUPS(bswitch);
static const struct watchdog_ops aspeed_wdt_ops = {
.start = aspeed_wdt_start,
.stop = aspeed_wdt_stop,
.ping = aspeed_wdt_ping,
.set_timeout = aspeed_wdt_set_timeout,
.restart = aspeed_wdt_restart,
.owner = THIS_MODULE,
};
static const struct watchdog_info aspeed_wdt_info = {
.options = WDIOF_KEEPALIVEPING
| WDIOF_MAGICCLOSE
| WDIOF_SETTIMEOUT,
.identity = KBUILD_MODNAME,
};
static int aspeed_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
const struct aspeed_wdt_config *config;
const struct of_device_id *ofdid;
struct aspeed_wdt *wdt;
struct device_node *np;
const char *reset_type;
u32 duration;
u32 status;
int ret;
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
wdt->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(wdt->base))
return PTR_ERR(wdt->base);
wdt->wdd.info = &aspeed_wdt_info;
wdt->wdd.ops = &aspeed_wdt_ops;
wdt->wdd.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT_MS;
wdt->wdd.parent = dev;
wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;
watchdog_init_timeout(&wdt->wdd, 0, dev);
np = dev->of_node;
ofdid = of_match_node(aspeed_wdt_of_table, np);
if (!ofdid)
return -EINVAL;
config = ofdid->data;
/*
* On clock rates:
* - ast2400 wdt can run at PCLK, or 1MHz
* - ast2500 only runs at 1MHz, hard coding bit 4 to 1
* - ast2600 always runs at 1MHz
*
* Set the ast2400 to run at 1MHz as it simplifies the driver.
*/
if (of_device_is_compatible(np, "aspeed,ast2400-wdt"))
wdt->ctrl = WDT_CTRL_1MHZ_CLK;
/*
* Control reset on a per-device basis to ensure the
* host is not affected by a BMC reboot
*/
ret = of_property_read_string(np, "aspeed,reset-type", &reset_type);
if (ret) {
wdt->ctrl |= WDT_CTRL_RESET_MODE_SOC | WDT_CTRL_RESET_SYSTEM;
} else {
if (!strcmp(reset_type, "cpu"))
wdt->ctrl |= WDT_CTRL_RESET_MODE_ARM_CPU |
WDT_CTRL_RESET_SYSTEM;
else if (!strcmp(reset_type, "soc"))
wdt->ctrl |= WDT_CTRL_RESET_MODE_SOC |
WDT_CTRL_RESET_SYSTEM;
else if (!strcmp(reset_type, "system"))
wdt->ctrl |= WDT_CTRL_RESET_MODE_FULL_CHIP |
WDT_CTRL_RESET_SYSTEM;
else if (strcmp(reset_type, "none"))
return -EINVAL;
}
if (of_property_read_bool(np, "aspeed,external-signal"))
wdt->ctrl |= WDT_CTRL_WDT_EXT;
if (of_property_read_bool(np, "aspeed,alt-boot"))
wdt->ctrl |= WDT_CTRL_BOOT_SECONDARY;
if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE) {
/*
* The watchdog is running, but invoke aspeed_wdt_start() to
* write wdt->ctrl to WDT_CTRL to ensure the watchdog's
* configuration conforms to the driver's expectations.
* Primarily, ensure we're using the 1MHz clock source.
*/
aspeed_wdt_start(&wdt->wdd);
set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
}
if ((of_device_is_compatible(np, "aspeed,ast2500-wdt")) ||
(of_device_is_compatible(np, "aspeed,ast2600-wdt"))) {
u32 reg = readl(wdt->base + WDT_RESET_WIDTH);
reg &= config->ext_pulse_width_mask;
if (of_property_read_bool(np, "aspeed,ext-push-pull"))
reg |= WDT_PUSH_PULL_MAGIC;
else
reg |= WDT_OPEN_DRAIN_MAGIC;
writel(reg, wdt->base + WDT_RESET_WIDTH);
reg &= config->ext_pulse_width_mask;
if (of_property_read_bool(np, "aspeed,ext-active-high"))
reg |= WDT_ACTIVE_HIGH_MAGIC;
else
reg |= WDT_ACTIVE_LOW_MAGIC;
writel(reg, wdt->base + WDT_RESET_WIDTH);
}
if (!of_property_read_u32(np, "aspeed,ext-pulse-duration", &duration)) {
u32 max_duration = config->ext_pulse_width_mask + 1;
if (duration == 0 || duration > max_duration) {
dev_err(dev, "Invalid pulse duration: %uus\n",
duration);
duration = max(1U, min(max_duration, duration));
dev_info(dev, "Pulse duration set to %uus\n",
duration);
}
/*
* The watchdog is always configured with a 1MHz source, so
* there is no need to scale the microsecond value. However we
* need to offset it - from the datasheet:
*
* "This register decides the asserting duration of wdt_ext and
* wdt_rstarm signal. The default value is 0xFF. It means the
* default asserting duration of wdt_ext and wdt_rstarm is
* 256us."
*
* This implies a value of 0 gives a 1us pulse.
*/
writel(duration - 1, wdt->base + WDT_RESET_WIDTH);
}
status = readl(wdt->base + WDT_TIMEOUT_STATUS);
if (status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY) {
wdt->wdd.bootstatus = WDIOF_CARDRESET;
if (of_device_is_compatible(np, "aspeed,ast2400-wdt") ||
of_device_is_compatible(np, "aspeed,ast2500-wdt"))
wdt->wdd.groups = bswitch_groups;
}
dev_set_drvdata(dev, wdt);
return devm_watchdog_register_device(dev, &wdt->wdd);
}
static struct platform_driver aspeed_watchdog_driver = {
.probe = aspeed_wdt_probe,
.driver = {
.name = KBUILD_MODNAME,
.of_match_table = of_match_ptr(aspeed_wdt_of_table),
},
};
static int __init aspeed_wdt_init(void)
{
return platform_driver_register(&aspeed_watchdog_driver);
}
arch_initcall(aspeed_wdt_init);
static void __exit aspeed_wdt_exit(void)
{
platform_driver_unregister(&aspeed_watchdog_driver);
}
module_exit(aspeed_wdt_exit);
MODULE_DESCRIPTION("Aspeed Watchdog Driver");
MODULE_LICENSE("GPL");