1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause 2 /* 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 0x0 20 #define GXBB_WDT_TCNT_REG 0x8 21 #define GXBB_WDT_RSET_REG 0xc 22 23 #define GXBB_WDT_CTRL_CLKDIV_EN BIT(25) 24 #define GXBB_WDT_CTRL_CLK_EN BIT(24) 25 #define GXBB_WDT_CTRL_EE_RESET BIT(21) 26 #define GXBB_WDT_CTRL_EN BIT(18) 27 #define GXBB_WDT_CTRL_DIV_MASK (BIT(18) - 1) 28 29 #define GXBB_WDT_TCNT_SETUP_MASK (BIT(16) - 1) 30 #define GXBB_WDT_TCNT_CNT_SHIFT 16 31 32 struct meson_gxbb_wdt { 33 void __iomem *reg_base; 34 struct watchdog_device wdt_dev; 35 struct clk *clk; 36 }; 37 38 static int meson_gxbb_wdt_start(struct watchdog_device *wdt_dev) 39 { 40 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); 41 42 writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) | GXBB_WDT_CTRL_EN, 43 data->reg_base + GXBB_WDT_CTRL_REG); 44 45 return 0; 46 } 47 48 static int meson_gxbb_wdt_stop(struct watchdog_device *wdt_dev) 49 { 50 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); 51 52 writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) & ~GXBB_WDT_CTRL_EN, 53 data->reg_base + GXBB_WDT_CTRL_REG); 54 55 return 0; 56 } 57 58 static int meson_gxbb_wdt_ping(struct watchdog_device *wdt_dev) 59 { 60 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); 61 62 writel(0, data->reg_base + GXBB_WDT_RSET_REG); 63 64 return 0; 65 } 66 67 static int meson_gxbb_wdt_set_timeout(struct watchdog_device *wdt_dev, 68 unsigned int timeout) 69 { 70 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); 71 unsigned long tcnt = timeout * 1000; 72 73 if (tcnt > GXBB_WDT_TCNT_SETUP_MASK) 74 tcnt = GXBB_WDT_TCNT_SETUP_MASK; 75 76 wdt_dev->timeout = timeout; 77 78 meson_gxbb_wdt_ping(wdt_dev); 79 80 writel(tcnt, data->reg_base + GXBB_WDT_TCNT_REG); 81 82 return 0; 83 } 84 85 static unsigned int meson_gxbb_wdt_get_timeleft(struct watchdog_device *wdt_dev) 86 { 87 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); 88 unsigned long reg; 89 90 reg = readl(data->reg_base + GXBB_WDT_TCNT_REG); 91 92 return ((reg >> GXBB_WDT_TCNT_CNT_SHIFT) - 93 (reg & GXBB_WDT_TCNT_SETUP_MASK)) / 1000; 94 } 95 96 static const struct watchdog_ops meson_gxbb_wdt_ops = { 97 .start = meson_gxbb_wdt_start, 98 .stop = meson_gxbb_wdt_stop, 99 .ping = meson_gxbb_wdt_ping, 100 .set_timeout = meson_gxbb_wdt_set_timeout, 101 .get_timeleft = meson_gxbb_wdt_get_timeleft, 102 }; 103 104 static const struct watchdog_info meson_gxbb_wdt_info = { 105 .identity = "Meson GXBB Watchdog", 106 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 107 }; 108 109 static int __maybe_unused meson_gxbb_wdt_resume(struct device *dev) 110 { 111 struct meson_gxbb_wdt *data = dev_get_drvdata(dev); 112 113 if (watchdog_active(&data->wdt_dev)) 114 meson_gxbb_wdt_start(&data->wdt_dev); 115 116 return 0; 117 } 118 119 static int __maybe_unused meson_gxbb_wdt_suspend(struct device *dev) 120 { 121 struct meson_gxbb_wdt *data = dev_get_drvdata(dev); 122 123 if (watchdog_active(&data->wdt_dev)) 124 meson_gxbb_wdt_stop(&data->wdt_dev); 125 126 return 0; 127 } 128 129 static const struct dev_pm_ops meson_gxbb_wdt_pm_ops = { 130 SET_SYSTEM_SLEEP_PM_OPS(meson_gxbb_wdt_suspend, meson_gxbb_wdt_resume) 131 }; 132 133 static const struct of_device_id meson_gxbb_wdt_dt_ids[] = { 134 { .compatible = "amlogic,meson-gxbb-wdt", }, 135 { /* sentinel */ }, 136 }; 137 MODULE_DEVICE_TABLE(of, meson_gxbb_wdt_dt_ids); 138 139 static int meson_gxbb_wdt_probe(struct platform_device *pdev) 140 { 141 struct meson_gxbb_wdt *data; 142 struct resource *res; 143 int ret; 144 145 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); 146 if (!data) 147 return -ENOMEM; 148 149 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 150 data->reg_base = devm_ioremap_resource(&pdev->dev, res); 151 if (IS_ERR(data->reg_base)) 152 return PTR_ERR(data->reg_base); 153 154 data->clk = devm_clk_get(&pdev->dev, NULL); 155 if (IS_ERR(data->clk)) 156 return PTR_ERR(data->clk); 157 158 ret = clk_prepare_enable(data->clk); 159 if (ret) 160 return ret; 161 162 platform_set_drvdata(pdev, data); 163 164 data->wdt_dev.parent = &pdev->dev; 165 data->wdt_dev.info = &meson_gxbb_wdt_info; 166 data->wdt_dev.ops = &meson_gxbb_wdt_ops; 167 data->wdt_dev.max_hw_heartbeat_ms = GXBB_WDT_TCNT_SETUP_MASK; 168 data->wdt_dev.min_timeout = 1; 169 data->wdt_dev.timeout = DEFAULT_TIMEOUT; 170 watchdog_set_drvdata(&data->wdt_dev, data); 171 172 /* Setup with 1ms timebase */ 173 writel(((clk_get_rate(data->clk) / 1000) & GXBB_WDT_CTRL_DIV_MASK) | 174 GXBB_WDT_CTRL_EE_RESET | 175 GXBB_WDT_CTRL_CLK_EN | 176 GXBB_WDT_CTRL_CLKDIV_EN, 177 data->reg_base + GXBB_WDT_CTRL_REG); 178 179 meson_gxbb_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout); 180 181 ret = watchdog_register_device(&data->wdt_dev); 182 if (ret) { 183 clk_disable_unprepare(data->clk); 184 return ret; 185 } 186 187 return 0; 188 } 189 190 static int meson_gxbb_wdt_remove(struct platform_device *pdev) 191 { 192 struct meson_gxbb_wdt *data = platform_get_drvdata(pdev); 193 194 watchdog_unregister_device(&data->wdt_dev); 195 196 clk_disable_unprepare(data->clk); 197 198 return 0; 199 } 200 201 static void meson_gxbb_wdt_shutdown(struct platform_device *pdev) 202 { 203 struct meson_gxbb_wdt *data = platform_get_drvdata(pdev); 204 205 meson_gxbb_wdt_stop(&data->wdt_dev); 206 } 207 208 static struct platform_driver meson_gxbb_wdt_driver = { 209 .probe = meson_gxbb_wdt_probe, 210 .remove = meson_gxbb_wdt_remove, 211 .shutdown = meson_gxbb_wdt_shutdown, 212 .driver = { 213 .name = "meson-gxbb-wdt", 214 .pm = &meson_gxbb_wdt_pm_ops, 215 .of_match_table = meson_gxbb_wdt_dt_ids, 216 }, 217 }; 218 219 module_platform_driver(meson_gxbb_wdt_driver); 220 221 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); 222 MODULE_DESCRIPTION("Amlogic Meson GXBB Watchdog timer driver"); 223 MODULE_LICENSE("Dual BSD/GPL"); 224