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- // 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);
- /* 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);
- 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);
- 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 <[email protected]>");
- 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");
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