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 static bool nowayout = WATCHDOG_NOWAYOUT; 33 module_param(nowayout, bool, 0); 34 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started default=" 35 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 36 37 static unsigned int timeout; 38 module_param(timeout, uint, 0); 39 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds=" 40 __MODULE_STRING(DEFAULT_TIMEOUT) ")"); 41 42 struct meson_gxbb_wdt { 43 void __iomem *reg_base; 44 struct watchdog_device wdt_dev; 45 struct clk *clk; 46 }; 47 48 static int meson_gxbb_wdt_start(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_stop(struct watchdog_device *wdt_dev) 59 { 60 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); 61 62 writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) & ~GXBB_WDT_CTRL_EN, 63 data->reg_base + GXBB_WDT_CTRL_REG); 64 65 return 0; 66 } 67 68 static int meson_gxbb_wdt_ping(struct watchdog_device *wdt_dev) 69 { 70 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); 71 72 writel(0, data->reg_base + GXBB_WDT_RSET_REG); 73 74 return 0; 75 } 76 77 static int meson_gxbb_wdt_set_timeout(struct watchdog_device *wdt_dev, 78 unsigned int timeout) 79 { 80 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); 81 unsigned long tcnt = timeout * 1000; 82 83 if (tcnt > GXBB_WDT_TCNT_SETUP_MASK) 84 tcnt = GXBB_WDT_TCNT_SETUP_MASK; 85 86 wdt_dev->timeout = timeout; 87 88 meson_gxbb_wdt_ping(wdt_dev); 89 90 writel(tcnt, data->reg_base + GXBB_WDT_TCNT_REG); 91 92 return 0; 93 } 94 95 static unsigned int meson_gxbb_wdt_get_timeleft(struct watchdog_device *wdt_dev) 96 { 97 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); 98 unsigned long reg; 99 100 reg = readl(data->reg_base + GXBB_WDT_TCNT_REG); 101 102 return ((reg & GXBB_WDT_TCNT_SETUP_MASK) - 103 (reg >> GXBB_WDT_TCNT_CNT_SHIFT)) / 1000; 104 } 105 106 static const struct watchdog_ops meson_gxbb_wdt_ops = { 107 .start = meson_gxbb_wdt_start, 108 .stop = meson_gxbb_wdt_stop, 109 .ping = meson_gxbb_wdt_ping, 110 .set_timeout = meson_gxbb_wdt_set_timeout, 111 .get_timeleft = meson_gxbb_wdt_get_timeleft, 112 }; 113 114 static const struct watchdog_info meson_gxbb_wdt_info = { 115 .identity = "Meson GXBB Watchdog", 116 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 117 }; 118 119 static int __maybe_unused meson_gxbb_wdt_resume(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_start(&data->wdt_dev); 125 126 return 0; 127 } 128 129 static int __maybe_unused meson_gxbb_wdt_suspend(struct device *dev) 130 { 131 struct meson_gxbb_wdt *data = dev_get_drvdata(dev); 132 133 if (watchdog_active(&data->wdt_dev)) 134 meson_gxbb_wdt_stop(&data->wdt_dev); 135 136 return 0; 137 } 138 139 static const struct dev_pm_ops meson_gxbb_wdt_pm_ops = { 140 SET_SYSTEM_SLEEP_PM_OPS(meson_gxbb_wdt_suspend, meson_gxbb_wdt_resume) 141 }; 142 143 static const struct of_device_id meson_gxbb_wdt_dt_ids[] = { 144 { .compatible = "amlogic,meson-gxbb-wdt", }, 145 { /* sentinel */ }, 146 }; 147 MODULE_DEVICE_TABLE(of, meson_gxbb_wdt_dt_ids); 148 149 static void meson_clk_disable_unprepare(void *data) 150 { 151 clk_disable_unprepare(data); 152 } 153 154 static int meson_gxbb_wdt_probe(struct platform_device *pdev) 155 { 156 struct device *dev = &pdev->dev; 157 struct meson_gxbb_wdt *data; 158 int ret; 159 u32 ctrl_reg; 160 161 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 162 if (!data) 163 return -ENOMEM; 164 165 data->reg_base = devm_platform_ioremap_resource(pdev, 0); 166 if (IS_ERR(data->reg_base)) 167 return PTR_ERR(data->reg_base); 168 169 data->clk = devm_clk_get(dev, NULL); 170 if (IS_ERR(data->clk)) 171 return PTR_ERR(data->clk); 172 173 ret = clk_prepare_enable(data->clk); 174 if (ret) 175 return ret; 176 ret = devm_add_action_or_reset(dev, meson_clk_disable_unprepare, 177 data->clk); 178 if (ret) 179 return ret; 180 181 platform_set_drvdata(pdev, data); 182 183 data->wdt_dev.parent = dev; 184 data->wdt_dev.info = &meson_gxbb_wdt_info; 185 data->wdt_dev.ops = &meson_gxbb_wdt_ops; 186 data->wdt_dev.max_hw_heartbeat_ms = GXBB_WDT_TCNT_SETUP_MASK; 187 data->wdt_dev.min_timeout = 1; 188 data->wdt_dev.timeout = DEFAULT_TIMEOUT; 189 watchdog_init_timeout(&data->wdt_dev, timeout, dev); 190 watchdog_set_nowayout(&data->wdt_dev, nowayout); 191 watchdog_set_drvdata(&data->wdt_dev, data); 192 193 ctrl_reg = readl(data->reg_base + GXBB_WDT_CTRL_REG) & 194 GXBB_WDT_CTRL_EN; 195 196 if (ctrl_reg) { 197 /* Watchdog is running - keep it running but extend timeout 198 * to the maximum while setting the timebase 199 */ 200 set_bit(WDOG_HW_RUNNING, &data->wdt_dev.status); 201 meson_gxbb_wdt_set_timeout(&data->wdt_dev, 202 GXBB_WDT_TCNT_SETUP_MASK / 1000); 203 } 204 205 /* Setup with 1ms timebase */ 206 ctrl_reg |= ((clk_get_rate(data->clk) / 1000) & 207 GXBB_WDT_CTRL_DIV_MASK) | 208 GXBB_WDT_CTRL_EE_RESET | 209 GXBB_WDT_CTRL_CLK_EN | 210 GXBB_WDT_CTRL_CLKDIV_EN; 211 212 writel(ctrl_reg, data->reg_base + GXBB_WDT_CTRL_REG); 213 meson_gxbb_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout); 214 215 return devm_watchdog_register_device(dev, &data->wdt_dev); 216 } 217 218 static struct platform_driver meson_gxbb_wdt_driver = { 219 .probe = meson_gxbb_wdt_probe, 220 .driver = { 221 .name = "meson-gxbb-wdt", 222 .pm = &meson_gxbb_wdt_pm_ops, 223 .of_match_table = meson_gxbb_wdt_dt_ids, 224 }, 225 }; 226 227 module_platform_driver(meson_gxbb_wdt_driver); 228 229 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); 230 MODULE_DESCRIPTION("Amlogic Meson GXBB Watchdog timer driver"); 231 MODULE_LICENSE("Dual BSD/GPL"); 232