233 lines · c
1// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause2/*3 * Copyright (c) 2016 BayLibre, SAS.4 * Author: Neil Armstrong <narmstrong@baylibre.com>5 *6 */7#include <linux/clk.h>8#include <linux/err.h>9#include <linux/io.h>10#include <linux/module.h>11#include <linux/of.h>12#include <linux/platform_device.h>13#include <linux/slab.h>14#include <linux/types.h>15#include <linux/watchdog.h>16 17#define DEFAULT_TIMEOUT 30 /* seconds */18 19#define GXBB_WDT_CTRL_REG 0x020#define GXBB_WDT_TCNT_REG 0x821#define GXBB_WDT_RSET_REG 0xc22 23#define GXBB_WDT_CTRL_CLKDIV_EN BIT(25)24#define GXBB_WDT_CTRL_CLK_EN BIT(24)25#define GXBB_WDT_CTRL_EN BIT(18)26#define GXBB_WDT_CTRL_DIV_MASK (BIT(18) - 1)27 28#define GXBB_WDT_TCNT_SETUP_MASK (BIT(16) - 1)29#define GXBB_WDT_TCNT_CNT_SHIFT 1630 31static bool nowayout = WATCHDOG_NOWAYOUT;32module_param(nowayout, bool, 0);33MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started default="34 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");35 36static unsigned int timeout;37module_param(timeout, uint, 0);38MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds="39 __MODULE_STRING(DEFAULT_TIMEOUT) ")");40 41struct meson_gxbb_wdt {42 void __iomem *reg_base;43 struct watchdog_device wdt_dev;44 struct clk *clk;45};46 47struct wdt_params {48 u32 rst;49};50 51static int meson_gxbb_wdt_start(struct watchdog_device *wdt_dev)52{53 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);54 55 writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) | GXBB_WDT_CTRL_EN,56 data->reg_base + GXBB_WDT_CTRL_REG);57 58 return 0;59}60 61static int meson_gxbb_wdt_stop(struct watchdog_device *wdt_dev)62{63 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);64 65 writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) & ~GXBB_WDT_CTRL_EN,66 data->reg_base + GXBB_WDT_CTRL_REG);67 68 return 0;69}70 71static int meson_gxbb_wdt_ping(struct watchdog_device *wdt_dev)72{73 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);74 75 writel(0, data->reg_base + GXBB_WDT_RSET_REG);76 77 return 0;78}79 80static int meson_gxbb_wdt_set_timeout(struct watchdog_device *wdt_dev,81 unsigned int timeout)82{83 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);84 unsigned long tcnt = timeout * 1000;85 86 if (tcnt > GXBB_WDT_TCNT_SETUP_MASK)87 tcnt = GXBB_WDT_TCNT_SETUP_MASK;88 89 wdt_dev->timeout = timeout;90 91 meson_gxbb_wdt_ping(wdt_dev);92 93 writel(tcnt, data->reg_base + GXBB_WDT_TCNT_REG);94 95 return 0;96}97 98static unsigned int meson_gxbb_wdt_get_timeleft(struct watchdog_device *wdt_dev)99{100 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);101 unsigned long reg;102 103 reg = readl(data->reg_base + GXBB_WDT_TCNT_REG);104 105 return ((reg & GXBB_WDT_TCNT_SETUP_MASK) -106 (reg >> GXBB_WDT_TCNT_CNT_SHIFT)) / 1000;107}108 109static const struct watchdog_ops meson_gxbb_wdt_ops = {110 .start = meson_gxbb_wdt_start,111 .stop = meson_gxbb_wdt_stop,112 .ping = meson_gxbb_wdt_ping,113 .set_timeout = meson_gxbb_wdt_set_timeout,114 .get_timeleft = meson_gxbb_wdt_get_timeleft,115};116 117static const struct watchdog_info meson_gxbb_wdt_info = {118 .identity = "Meson GXBB Watchdog",119 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,120};121 122static int __maybe_unused meson_gxbb_wdt_resume(struct device *dev)123{124 struct meson_gxbb_wdt *data = dev_get_drvdata(dev);125 126 if (watchdog_active(&data->wdt_dev))127 meson_gxbb_wdt_start(&data->wdt_dev);128 129 return 0;130}131 132static int __maybe_unused meson_gxbb_wdt_suspend(struct device *dev)133{134 struct meson_gxbb_wdt *data = dev_get_drvdata(dev);135 136 if (watchdog_active(&data->wdt_dev))137 meson_gxbb_wdt_stop(&data->wdt_dev);138 139 return 0;140}141 142static const struct dev_pm_ops meson_gxbb_wdt_pm_ops = {143 SET_SYSTEM_SLEEP_PM_OPS(meson_gxbb_wdt_suspend, meson_gxbb_wdt_resume)144};145 146static const struct wdt_params gxbb_params = {147 .rst = BIT(21),148};149 150static const struct wdt_params t7_params = {151 .rst = BIT(22),152};153 154static const struct of_device_id meson_gxbb_wdt_dt_ids[] = {155 { .compatible = "amlogic,meson-gxbb-wdt", .data = &gxbb_params, },156 { .compatible = "amlogic,t7-wdt", .data = &t7_params, },157 { /* sentinel */ },158};159MODULE_DEVICE_TABLE(of, meson_gxbb_wdt_dt_ids);160 161static int meson_gxbb_wdt_probe(struct platform_device *pdev)162{163 struct device *dev = &pdev->dev;164 struct meson_gxbb_wdt *data;165 struct wdt_params *params;166 u32 ctrl_reg;167 168 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);169 if (!data)170 return -ENOMEM;171 172 data->reg_base = devm_platform_ioremap_resource(pdev, 0);173 if (IS_ERR(data->reg_base))174 return PTR_ERR(data->reg_base);175 176 data->clk = devm_clk_get_enabled(dev, NULL);177 if (IS_ERR(data->clk))178 return PTR_ERR(data->clk);179 180 params = (struct wdt_params *)of_device_get_match_data(dev);181 182 platform_set_drvdata(pdev, data);183 184 data->wdt_dev.parent = dev;185 data->wdt_dev.info = &meson_gxbb_wdt_info;186 data->wdt_dev.ops = &meson_gxbb_wdt_ops;187 data->wdt_dev.max_hw_heartbeat_ms = GXBB_WDT_TCNT_SETUP_MASK;188 data->wdt_dev.min_timeout = 1;189 data->wdt_dev.timeout = DEFAULT_TIMEOUT;190 watchdog_init_timeout(&data->wdt_dev, timeout, dev);191 watchdog_set_nowayout(&data->wdt_dev, nowayout);192 watchdog_set_drvdata(&data->wdt_dev, data);193 194 ctrl_reg = readl(data->reg_base + GXBB_WDT_CTRL_REG) &195 GXBB_WDT_CTRL_EN;196 197 if (ctrl_reg) {198 /* Watchdog is running - keep it running but extend timeout199 * to the maximum while setting the timebase200 */201 set_bit(WDOG_HW_RUNNING, &data->wdt_dev.status);202 meson_gxbb_wdt_set_timeout(&data->wdt_dev,203 GXBB_WDT_TCNT_SETUP_MASK / 1000);204 }205 206 /* Setup with 1ms timebase */207 ctrl_reg |= ((clk_get_rate(data->clk) / 1000) &208 GXBB_WDT_CTRL_DIV_MASK) |209 params->rst |210 GXBB_WDT_CTRL_CLK_EN |211 GXBB_WDT_CTRL_CLKDIV_EN;212 213 writel(ctrl_reg, data->reg_base + GXBB_WDT_CTRL_REG);214 meson_gxbb_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout);215 216 return devm_watchdog_register_device(dev, &data->wdt_dev);217}218 219static struct platform_driver meson_gxbb_wdt_driver = {220 .probe = meson_gxbb_wdt_probe,221 .driver = {222 .name = "meson-gxbb-wdt",223 .pm = &meson_gxbb_wdt_pm_ops,224 .of_match_table = meson_gxbb_wdt_dt_ids,225 },226};227 228module_platform_driver(meson_gxbb_wdt_driver);229 230MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");231MODULE_DESCRIPTION("Amlogic Meson GXBB Watchdog timer driver");232MODULE_LICENSE("Dual BSD/GPL");233