diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/watchdog/rti_wdt.c | 356 |
1 files changed, 356 insertions, 0 deletions
diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c new file mode 100644 index 000000000..ea617c0f9 --- /dev/null +++ b/drivers/watchdog/rti_wdt.c @@ -0,0 +1,356 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Watchdog driver for the K3 RTI module + * + * (c) Copyright 2019-2020 Texas Instruments Inc. + * All rights reserved. + */ + +#include <linux/clk.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/types.h> +#include <linux/watchdog.h> + +#define DEFAULT_HEARTBEAT 60 + +/* Max heartbeat is calculated at 32kHz source clock */ +#define MAX_HEARTBEAT 1000 + +/* Timer register set definition */ +#define RTIDWDCTRL 0x90 +#define RTIDWDPRLD 0x94 +#define RTIWDSTATUS 0x98 +#define RTIWDKEY 0x9c +#define RTIDWDCNTR 0xa0 +#define RTIWWDRXCTRL 0xa4 +#define RTIWWDSIZECTRL 0xa8 + +#define RTIWWDRX_NMI 0xa + +#define RTIWWDSIZE_50P 0x50 +#define RTIWWDSIZE_25P 0x500 +#define RTIWWDSIZE_12P5 0x5000 +#define RTIWWDSIZE_6P25 0x50000 +#define RTIWWDSIZE_3P125 0x500000 + +#define WDENABLE_KEY 0xa98559da + +#define WDKEY_SEQ0 0xe51a +#define WDKEY_SEQ1 0xa35c + +#define WDT_PRELOAD_SHIFT 13 + +#define WDT_PRELOAD_MAX 0xfff + +#define DWDST BIT(1) + +static int heartbeat = DEFAULT_HEARTBEAT; + +/* + * struct to hold data for each WDT device + * @base - base io address of WD device + * @freq - source clock frequency of WDT + * @wdd - hold watchdog device as is in WDT core + */ +struct rti_wdt_device { + void __iomem *base; + unsigned long freq; + struct watchdog_device wdd; +}; + +static int rti_wdt_start(struct watchdog_device *wdd) +{ + u32 timer_margin; + struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd); + int ret; + + ret = pm_runtime_resume_and_get(wdd->parent); + if (ret) + return ret; + + /* set timeout period */ + timer_margin = (u64)wdd->timeout * wdt->freq; + timer_margin >>= WDT_PRELOAD_SHIFT; + if (timer_margin > WDT_PRELOAD_MAX) + timer_margin = WDT_PRELOAD_MAX; + writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD); + + /* + * RTI only supports a windowed mode, where the watchdog can only + * be petted during the open window; not too early or not too late. + * The HW configuration options only allow for the open window size + * to be 50% or less than that; we obviouly want to configure the open + * window as large as possible so we select the 50% option. + */ + wdd->min_hw_heartbeat_ms = 500 * wdd->timeout; + + /* Generate NMI when wdt expires */ + writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL); + + /* Open window size 50%; this is the largest window size available */ + writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL); + + readl_relaxed(wdt->base + RTIWWDSIZECTRL); + + /* enable watchdog */ + writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL); + return 0; +} + +static int rti_wdt_ping(struct watchdog_device *wdd) +{ + struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd); + + /* put watchdog in service state */ + writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY); + /* put watchdog in active state */ + writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY); + + return 0; +} + +static int rti_wdt_setup_hw_hb(struct watchdog_device *wdd, u32 wsize) +{ + /* + * RTI only supports a windowed mode, where the watchdog can only + * be petted during the open window; not too early or not too late. + * The HW configuration options only allow for the open window size + * to be 50% or less than that. + */ + switch (wsize) { + case RTIWWDSIZE_50P: + /* 50% open window => 50% min heartbeat */ + wdd->min_hw_heartbeat_ms = 500 * heartbeat; + break; + + case RTIWWDSIZE_25P: + /* 25% open window => 75% min heartbeat */ + wdd->min_hw_heartbeat_ms = 750 * heartbeat; + break; + + case RTIWWDSIZE_12P5: + /* 12.5% open window => 87.5% min heartbeat */ + wdd->min_hw_heartbeat_ms = 875 * heartbeat; + break; + + case RTIWWDSIZE_6P25: + /* 6.5% open window => 93.5% min heartbeat */ + wdd->min_hw_heartbeat_ms = 935 * heartbeat; + break; + + case RTIWWDSIZE_3P125: + /* 3.125% open window => 96.9% min heartbeat */ + wdd->min_hw_heartbeat_ms = 969 * heartbeat; + break; + + default: + return -EINVAL; + } + + return 0; +} + +static unsigned int rti_wdt_get_timeleft_ms(struct watchdog_device *wdd) +{ + u64 timer_counter; + u32 val; + struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd); + + /* if timeout has occurred then return 0 */ + val = readl_relaxed(wdt->base + RTIWDSTATUS); + if (val & DWDST) + return 0; + + timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR); + + timer_counter *= 1000; + + do_div(timer_counter, wdt->freq); + + return timer_counter; +} + +static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd) +{ + return rti_wdt_get_timeleft_ms(wdd) / 1000; +} + +static const struct watchdog_info rti_wdt_info = { + .options = WDIOF_KEEPALIVEPING, + .identity = "K3 RTI Watchdog", +}; + +static const struct watchdog_ops rti_wdt_ops = { + .owner = THIS_MODULE, + .start = rti_wdt_start, + .ping = rti_wdt_ping, + .get_timeleft = rti_wdt_get_timeleft, +}; + +static int rti_wdt_probe(struct platform_device *pdev) +{ + int ret = 0; + struct device *dev = &pdev->dev; + struct watchdog_device *wdd; + struct rti_wdt_device *wdt; + struct clk *clk; + u32 last_ping = 0; + + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); + if (!wdt) + return -ENOMEM; + + clk = clk_get(dev, NULL); + if (IS_ERR(clk)) + return dev_err_probe(dev, PTR_ERR(clk), "failed to get clock\n"); + + wdt->freq = clk_get_rate(clk); + + clk_put(clk); + + if (!wdt->freq) { + dev_err(dev, "Failed to get fck rate.\n"); + return -EINVAL; + } + + /* + * If watchdog is running at 32k clock, it is not accurate. + * Adjust frequency down in this case so that we don't pet + * the watchdog too often. + */ + if (wdt->freq < 32768) + wdt->freq = wdt->freq * 9 / 10; + + pm_runtime_enable(dev); + ret = pm_runtime_resume_and_get(dev); + if (ret < 0) { + pm_runtime_disable(&pdev->dev); + return dev_err_probe(dev, ret, "runtime pm failed\n"); + } + + platform_set_drvdata(pdev, wdt); + + wdd = &wdt->wdd; + wdd->info = &rti_wdt_info; + wdd->ops = &rti_wdt_ops; + wdd->min_timeout = 1; + wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) / + wdt->freq * 1000; + wdd->parent = dev; + + watchdog_set_drvdata(wdd, wdt); + watchdog_set_nowayout(wdd, 1); + watchdog_set_restart_priority(wdd, 128); + + wdt->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(wdt->base)) { + ret = PTR_ERR(wdt->base); + goto err_iomap; + } + + if (readl(wdt->base + RTIDWDCTRL) == WDENABLE_KEY) { + int preset_heartbeat; + u32 time_left_ms; + u64 heartbeat_ms; + u32 wsize; + + set_bit(WDOG_HW_RUNNING, &wdd->status); + time_left_ms = rti_wdt_get_timeleft_ms(wdd); + heartbeat_ms = readl(wdt->base + RTIDWDPRLD); + heartbeat_ms <<= WDT_PRELOAD_SHIFT; + heartbeat_ms *= 1000; + do_div(heartbeat_ms, wdt->freq); + preset_heartbeat = heartbeat_ms + 500; + preset_heartbeat /= 1000; + if (preset_heartbeat != heartbeat) + dev_warn(dev, "watchdog already running, ignoring heartbeat config!\n"); + + heartbeat = preset_heartbeat; + + wsize = readl(wdt->base + RTIWWDSIZECTRL); + ret = rti_wdt_setup_hw_hb(wdd, wsize); + if (ret) { + dev_err(dev, "bad window size.\n"); + goto err_iomap; + } + + last_ping = heartbeat_ms - time_left_ms; + if (time_left_ms > heartbeat_ms) { + dev_warn(dev, "time_left > heartbeat? Assuming last ping just before now.\n"); + last_ping = 0; + } + } + + watchdog_init_timeout(wdd, heartbeat, dev); + + ret = watchdog_register_device(wdd); + if (ret) { + dev_err(dev, "cannot register watchdog device\n"); + goto err_iomap; + } + + if (last_ping) + watchdog_set_last_hw_keepalive(wdd, last_ping); + + if (!watchdog_hw_running(wdd)) + pm_runtime_put_sync(&pdev->dev); + + return 0; + +err_iomap: + pm_runtime_put_sync(&pdev->dev); + pm_runtime_disable(&pdev->dev); + + return ret; +} + +static int rti_wdt_remove(struct platform_device *pdev) +{ + struct rti_wdt_device *wdt = platform_get_drvdata(pdev); + + watchdog_unregister_device(&wdt->wdd); + + if (!pm_runtime_suspended(&pdev->dev)) + pm_runtime_put(&pdev->dev); + + pm_runtime_disable(&pdev->dev); + + return 0; +} + +static const struct of_device_id rti_wdt_of_match[] = { + { .compatible = "ti,j7-rti-wdt", }, + {}, +}; +MODULE_DEVICE_TABLE(of, rti_wdt_of_match); + +static struct platform_driver rti_wdt_driver = { + .driver = { + .name = "rti-wdt", + .of_match_table = rti_wdt_of_match, + }, + .probe = rti_wdt_probe, + .remove = rti_wdt_remove, +}; + +module_platform_driver(rti_wdt_driver); + +MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>"); +MODULE_DESCRIPTION("K3 RTI 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:rti-wdt"); |