Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Watchdog driver for Renesas WDT watchdog |
| 3 | * |
Wolfram Sang | 1f18559 | 2017-07-26 23:54:39 +0200 | [diff] [blame] | 4 | * Copyright (C) 2015-17 Wolfram Sang, Sang Engineering <wsa@sang-engineering.com> |
| 5 | * Copyright (C) 2015-17 Renesas Electronics Corporation |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify it |
| 8 | * under the terms of the GNU General Public License version 2 as published by |
| 9 | * the Free Software Foundation. |
| 10 | */ |
| 11 | #include <linux/bitops.h> |
| 12 | #include <linux/clk.h> |
| 13 | #include <linux/io.h> |
| 14 | #include <linux/kernel.h> |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/of.h> |
| 17 | #include <linux/platform_device.h> |
| 18 | #include <linux/pm_runtime.h> |
Fabrizio Castro | 3fe95e6 | 2018-03-05 15:30:25 +0000 | [diff] [blame^] | 19 | #include <linux/smp.h> |
| 20 | #include <linux/sys_soc.h> |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 21 | #include <linux/watchdog.h> |
| 22 | |
| 23 | #define RWTCNT 0 |
| 24 | #define RWTCSRA 4 |
| 25 | #define RWTCSRA_WOVF BIT(4) |
| 26 | #define RWTCSRA_WRFLG BIT(5) |
| 27 | #define RWTCSRA_TME BIT(7) |
Wolfram Sang | 03a196f | 2017-07-19 10:27:55 +0200 | [diff] [blame] | 28 | #define RWTCSRB 8 |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 29 | |
| 30 | #define RWDT_DEFAULT_TIMEOUT 60U |
| 31 | |
Wolfram Sang | 82f64cd | 2017-07-19 10:27:54 +0200 | [diff] [blame] | 32 | /* |
| 33 | * In probe, clk_rate is checked to be not more than 16 bit * biggest clock |
Wolfram Sang | 03a196f | 2017-07-19 10:27:55 +0200 | [diff] [blame] | 34 | * divider (12 bits). d is only a factor to fully utilize the WDT counter and |
Wolfram Sang | 82f64cd | 2017-07-19 10:27:54 +0200 | [diff] [blame] | 35 | * will not exceed its 16 bits. Thus, no overflow, we stay below 32 bits. |
| 36 | */ |
| 37 | #define MUL_BY_CLKS_PER_SEC(p, d) \ |
| 38 | DIV_ROUND_UP((d) * (p)->clk_rate, clk_divs[(p)->cks]) |
| 39 | |
Wolfram Sang | 03a196f | 2017-07-19 10:27:55 +0200 | [diff] [blame] | 40 | /* d is 16 bit, clk_divs 12 bit -> no 32 bit overflow */ |
Wolfram Sang | 82f64cd | 2017-07-19 10:27:54 +0200 | [diff] [blame] | 41 | #define DIV_BY_CLKS_PER_SEC(p, d) ((d) * clk_divs[(p)->cks] / (p)->clk_rate) |
| 42 | |
Wolfram Sang | 03a196f | 2017-07-19 10:27:55 +0200 | [diff] [blame] | 43 | static const unsigned int clk_divs[] = { 1, 4, 16, 32, 64, 128, 1024, 4096 }; |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 44 | |
| 45 | static bool nowayout = WATCHDOG_NOWAYOUT; |
| 46 | module_param(nowayout, bool, 0); |
| 47 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
| 48 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 49 | |
| 50 | struct rwdt_priv { |
| 51 | void __iomem *base; |
| 52 | struct watchdog_device wdev; |
Wolfram Sang | 82f64cd | 2017-07-19 10:27:54 +0200 | [diff] [blame] | 53 | unsigned long clk_rate; |
Fabrizio Castro | 07278ca | 2018-03-05 15:30:24 +0000 | [diff] [blame] | 54 | u16 time_left; |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 55 | u8 cks; |
| 56 | }; |
| 57 | |
| 58 | static void rwdt_write(struct rwdt_priv *priv, u32 val, unsigned int reg) |
| 59 | { |
| 60 | if (reg == RWTCNT) |
| 61 | val |= 0x5a5a0000; |
| 62 | else |
| 63 | val |= 0xa5a5a500; |
| 64 | |
| 65 | writel_relaxed(val, priv->base + reg); |
| 66 | } |
| 67 | |
| 68 | static int rwdt_init_timeout(struct watchdog_device *wdev) |
| 69 | { |
| 70 | struct rwdt_priv *priv = watchdog_get_drvdata(wdev); |
| 71 | |
Wolfram Sang | 82f64cd | 2017-07-19 10:27:54 +0200 | [diff] [blame] | 72 | rwdt_write(priv, 65536 - MUL_BY_CLKS_PER_SEC(priv, wdev->timeout), RWTCNT); |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 73 | |
| 74 | return 0; |
| 75 | } |
| 76 | |
| 77 | static int rwdt_start(struct watchdog_device *wdev) |
| 78 | { |
| 79 | struct rwdt_priv *priv = watchdog_get_drvdata(wdev); |
| 80 | |
Wolfram Sang | 3be4294 | 2017-07-26 23:54:37 +0200 | [diff] [blame] | 81 | pm_runtime_get_sync(wdev->parent); |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 82 | |
Wolfram Sang | 03a196f | 2017-07-19 10:27:55 +0200 | [diff] [blame] | 83 | rwdt_write(priv, 0, RWTCSRB); |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 84 | rwdt_write(priv, priv->cks, RWTCSRA); |
| 85 | rwdt_init_timeout(wdev); |
| 86 | |
| 87 | while (readb_relaxed(priv->base + RWTCSRA) & RWTCSRA_WRFLG) |
| 88 | cpu_relax(); |
| 89 | |
| 90 | rwdt_write(priv, priv->cks | RWTCSRA_TME, RWTCSRA); |
| 91 | |
| 92 | return 0; |
| 93 | } |
| 94 | |
| 95 | static int rwdt_stop(struct watchdog_device *wdev) |
| 96 | { |
| 97 | struct rwdt_priv *priv = watchdog_get_drvdata(wdev); |
| 98 | |
| 99 | rwdt_write(priv, priv->cks, RWTCSRA); |
Wolfram Sang | 3be4294 | 2017-07-26 23:54:37 +0200 | [diff] [blame] | 100 | pm_runtime_put(wdev->parent); |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 101 | |
| 102 | return 0; |
| 103 | } |
| 104 | |
| 105 | static unsigned int rwdt_get_timeleft(struct watchdog_device *wdev) |
| 106 | { |
| 107 | struct rwdt_priv *priv = watchdog_get_drvdata(wdev); |
| 108 | u16 val = readw_relaxed(priv->base + RWTCNT); |
| 109 | |
Wolfram Sang | 82f64cd | 2017-07-19 10:27:54 +0200 | [diff] [blame] | 110 | return DIV_BY_CLKS_PER_SEC(priv, 65536 - val); |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 111 | } |
| 112 | |
| 113 | static const struct watchdog_info rwdt_ident = { |
| 114 | .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, |
| 115 | .identity = "Renesas WDT Watchdog", |
| 116 | }; |
| 117 | |
| 118 | static const struct watchdog_ops rwdt_ops = { |
| 119 | .owner = THIS_MODULE, |
| 120 | .start = rwdt_start, |
| 121 | .stop = rwdt_stop, |
| 122 | .ping = rwdt_init_timeout, |
| 123 | .get_timeleft = rwdt_get_timeleft, |
| 124 | }; |
| 125 | |
Fabrizio Castro | 3fe95e6 | 2018-03-05 15:30:25 +0000 | [diff] [blame^] | 126 | #if defined(CONFIG_ARCH_RCAR_GEN2) && defined(CONFIG_SMP) |
| 127 | /* |
| 128 | * Watchdog-reset integration is broken on early revisions of R-Car Gen2 SoCs |
| 129 | */ |
| 130 | static const struct soc_device_attribute rwdt_quirks_match[] = { |
| 131 | { |
| 132 | .soc_id = "r8a7790", |
| 133 | .revision = "ES1.*", |
| 134 | .data = (void *)1, /* needs single CPU */ |
| 135 | }, { |
| 136 | .soc_id = "r8a7791", |
| 137 | .revision = "ES[12].*", |
| 138 | .data = (void *)1, /* needs single CPU */ |
| 139 | }, { |
| 140 | .soc_id = "r8a7792", |
| 141 | .revision = "*", |
| 142 | .data = (void *)0, /* needs SMP disabled */ |
| 143 | }, |
| 144 | { /* sentinel */ } |
| 145 | }; |
| 146 | |
| 147 | static bool rwdt_blacklisted(struct device *dev) |
| 148 | { |
| 149 | const struct soc_device_attribute *attr; |
| 150 | |
| 151 | attr = soc_device_match(rwdt_quirks_match); |
| 152 | if (attr && setup_max_cpus > (uintptr_t)attr->data) { |
| 153 | dev_info(dev, "Watchdog blacklisted on %s %s\n", attr->soc_id, |
| 154 | attr->revision); |
| 155 | return true; |
| 156 | } |
| 157 | |
| 158 | return false; |
| 159 | } |
| 160 | #else /* !CONFIG_ARCH_RCAR_GEN2 || !CONFIG_SMP */ |
| 161 | static inline bool rwdt_blacklisted(struct device *dev) { return false; } |
| 162 | #endif /* !CONFIG_ARCH_RCAR_GEN2 || !CONFIG_SMP */ |
| 163 | |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 164 | static int rwdt_probe(struct platform_device *pdev) |
| 165 | { |
| 166 | struct rwdt_priv *priv; |
| 167 | struct resource *res; |
Wolfram Sang | 9c22b6d | 2017-07-26 23:54:38 +0200 | [diff] [blame] | 168 | struct clk *clk; |
Wolfram Sang | 82f64cd | 2017-07-19 10:27:54 +0200 | [diff] [blame] | 169 | unsigned long clks_per_sec; |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 170 | int ret, i; |
| 171 | |
Fabrizio Castro | 3fe95e6 | 2018-03-05 15:30:25 +0000 | [diff] [blame^] | 172 | if (rwdt_blacklisted(&pdev->dev)) |
| 173 | return -ENODEV; |
| 174 | |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 175 | priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
| 176 | if (!priv) |
| 177 | return -ENOMEM; |
| 178 | |
| 179 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 180 | priv->base = devm_ioremap_resource(&pdev->dev, res); |
| 181 | if (IS_ERR(priv->base)) |
| 182 | return PTR_ERR(priv->base); |
| 183 | |
Wolfram Sang | 9c22b6d | 2017-07-26 23:54:38 +0200 | [diff] [blame] | 184 | clk = devm_clk_get(&pdev->dev, NULL); |
| 185 | if (IS_ERR(clk)) |
| 186 | return PTR_ERR(clk); |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 187 | |
Wolfram Sang | 3be4294 | 2017-07-26 23:54:37 +0200 | [diff] [blame] | 188 | pm_runtime_enable(&pdev->dev); |
| 189 | |
| 190 | pm_runtime_get_sync(&pdev->dev); |
Wolfram Sang | 9c22b6d | 2017-07-26 23:54:38 +0200 | [diff] [blame] | 191 | priv->clk_rate = clk_get_rate(clk); |
Wolfram Sang | 3be4294 | 2017-07-26 23:54:37 +0200 | [diff] [blame] | 192 | pm_runtime_put(&pdev->dev); |
| 193 | |
| 194 | if (!priv->clk_rate) { |
| 195 | ret = -ENOENT; |
| 196 | goto out_pm_disable; |
| 197 | } |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 198 | |
| 199 | for (i = ARRAY_SIZE(clk_divs) - 1; i >= 0; i--) { |
Wolfram Sang | 82f64cd | 2017-07-19 10:27:54 +0200 | [diff] [blame] | 200 | clks_per_sec = priv->clk_rate / clk_divs[i]; |
Wolfram Sang | b51247c | 2017-07-19 10:27:52 +0200 | [diff] [blame] | 201 | if (clks_per_sec && clks_per_sec < 65536) { |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 202 | priv->cks = i; |
| 203 | break; |
| 204 | } |
| 205 | } |
| 206 | |
Wolfram Sang | b51247c | 2017-07-19 10:27:52 +0200 | [diff] [blame] | 207 | if (i < 0) { |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 208 | dev_err(&pdev->dev, "Can't find suitable clock divider\n"); |
Wolfram Sang | 3be4294 | 2017-07-26 23:54:37 +0200 | [diff] [blame] | 209 | ret = -ERANGE; |
| 210 | goto out_pm_disable; |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 211 | } |
| 212 | |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 213 | priv->wdev.info = &rwdt_ident, |
| 214 | priv->wdev.ops = &rwdt_ops, |
| 215 | priv->wdev.parent = &pdev->dev; |
| 216 | priv->wdev.min_timeout = 1; |
Wolfram Sang | 82f64cd | 2017-07-19 10:27:54 +0200 | [diff] [blame] | 217 | priv->wdev.max_timeout = DIV_BY_CLKS_PER_SEC(priv, 65536); |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 218 | priv->wdev.timeout = min(priv->wdev.max_timeout, RWDT_DEFAULT_TIMEOUT); |
| 219 | |
| 220 | platform_set_drvdata(pdev, priv); |
| 221 | watchdog_set_drvdata(&priv->wdev, priv); |
| 222 | watchdog_set_nowayout(&priv->wdev, nowayout); |
| 223 | |
| 224 | /* This overrides the default timeout only if DT configuration was found */ |
| 225 | ret = watchdog_init_timeout(&priv->wdev, 0, &pdev->dev); |
| 226 | if (ret) |
| 227 | dev_warn(&pdev->dev, "Specified timeout value invalid, using default\n"); |
| 228 | |
| 229 | ret = watchdog_register_device(&priv->wdev); |
Wolfram Sang | 3be4294 | 2017-07-26 23:54:37 +0200 | [diff] [blame] | 230 | if (ret < 0) |
| 231 | goto out_pm_disable; |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 232 | |
| 233 | return 0; |
Wolfram Sang | 3be4294 | 2017-07-26 23:54:37 +0200 | [diff] [blame] | 234 | |
| 235 | out_pm_disable: |
| 236 | pm_runtime_disable(&pdev->dev); |
| 237 | return ret; |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 238 | } |
| 239 | |
| 240 | static int rwdt_remove(struct platform_device *pdev) |
| 241 | { |
| 242 | struct rwdt_priv *priv = platform_get_drvdata(pdev); |
| 243 | |
| 244 | watchdog_unregister_device(&priv->wdev); |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 245 | pm_runtime_disable(&pdev->dev); |
| 246 | |
| 247 | return 0; |
| 248 | } |
| 249 | |
Fabrizio Castro | 07278ca | 2018-03-05 15:30:24 +0000 | [diff] [blame] | 250 | static int __maybe_unused rwdt_suspend(struct device *dev) |
| 251 | { |
| 252 | struct rwdt_priv *priv = dev_get_drvdata(dev); |
| 253 | |
| 254 | if (watchdog_active(&priv->wdev)) { |
| 255 | priv->time_left = readw(priv->base + RWTCNT); |
| 256 | rwdt_stop(&priv->wdev); |
| 257 | } |
| 258 | return 0; |
| 259 | } |
| 260 | |
| 261 | static int __maybe_unused rwdt_resume(struct device *dev) |
| 262 | { |
| 263 | struct rwdt_priv *priv = dev_get_drvdata(dev); |
| 264 | |
| 265 | if (watchdog_active(&priv->wdev)) { |
| 266 | rwdt_start(&priv->wdev); |
| 267 | rwdt_write(priv, priv->time_left, RWTCNT); |
| 268 | } |
| 269 | return 0; |
| 270 | } |
| 271 | |
| 272 | static SIMPLE_DEV_PM_OPS(rwdt_pm_ops, rwdt_suspend, rwdt_resume); |
| 273 | |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 274 | static const struct of_device_id rwdt_ids[] = { |
Fabrizio Castro | 3fe95e6 | 2018-03-05 15:30:25 +0000 | [diff] [blame^] | 275 | { .compatible = "renesas,rcar-gen2-wdt", }, |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 276 | { .compatible = "renesas,rcar-gen3-wdt", }, |
| 277 | { /* sentinel */ } |
| 278 | }; |
| 279 | MODULE_DEVICE_TABLE(of, rwdt_ids); |
| 280 | |
| 281 | static struct platform_driver rwdt_driver = { |
| 282 | .driver = { |
| 283 | .name = "renesas_wdt", |
| 284 | .of_match_table = rwdt_ids, |
Fabrizio Castro | 07278ca | 2018-03-05 15:30:24 +0000 | [diff] [blame] | 285 | .pm = &rwdt_pm_ops, |
Wolfram Sang | bd99b68 | 2016-04-01 13:56:23 +0200 | [diff] [blame] | 286 | }, |
| 287 | .probe = rwdt_probe, |
| 288 | .remove = rwdt_remove, |
| 289 | }; |
| 290 | module_platform_driver(rwdt_driver); |
| 291 | |
| 292 | MODULE_DESCRIPTION("Renesas WDT Watchdog Driver"); |
| 293 | MODULE_LICENSE("GPL v2"); |
| 294 | MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>"); |