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| 1 | +// SPDX-License-Identifier: GPL-2.0 |
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| 1 | 2 | /* |
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| 2 | 3 | * Watchdog driver for Renesas WDT watchdog |
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| 3 | 4 | * |
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| 4 | 5 | * Copyright (C) 2015-17 Wolfram Sang, Sang Engineering <wsa@sang-engineering.com> |
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| 5 | 6 | * Copyright (C) 2015-17 Renesas Electronics Corporation |
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| 6 | | - * |
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| 7 | | - * This program is free software; you can redistribute it and/or modify it |
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| 8 | | - * under the terms of the GNU General Public License version 2 as published by |
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| 9 | | - * the Free Software Foundation. |
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| 10 | 7 | */ |
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| 11 | 8 | #include <linux/bitops.h> |
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| 12 | 9 | #include <linux/clk.h> |
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| 10 | +#include <linux/delay.h> |
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| 13 | 11 | #include <linux/io.h> |
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| 14 | 12 | #include <linux/kernel.h> |
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| 15 | 13 | #include <linux/module.h> |
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| .. | .. |
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| 51 | 49 | void __iomem *base; |
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| 52 | 50 | struct watchdog_device wdev; |
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| 53 | 51 | unsigned long clk_rate; |
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| 54 | | - u16 time_left; |
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| 55 | 52 | u8 cks; |
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| 56 | 53 | }; |
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| 57 | 54 | |
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| .. | .. |
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| 74 | 71 | return 0; |
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| 75 | 72 | } |
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| 76 | 73 | |
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| 74 | +static void rwdt_wait_cycles(struct rwdt_priv *priv, unsigned int cycles) |
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| 75 | +{ |
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| 76 | + unsigned int delay; |
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| 77 | + |
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| 78 | + delay = DIV_ROUND_UP(cycles * 1000000, priv->clk_rate); |
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| 79 | + |
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| 80 | + usleep_range(delay, 2 * delay); |
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| 81 | +} |
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| 82 | + |
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| 77 | 83 | static int rwdt_start(struct watchdog_device *wdev) |
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| 78 | 84 | { |
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| 79 | 85 | struct rwdt_priv *priv = watchdog_get_drvdata(wdev); |
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| .. | .. |
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| 84 | 90 | /* Stop the timer before we modify any register */ |
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| 85 | 91 | val = readb_relaxed(priv->base + RWTCSRA) & ~RWTCSRA_TME; |
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| 86 | 92 | rwdt_write(priv, val, RWTCSRA); |
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| 93 | + /* Delay 2 cycles before setting watchdog counter */ |
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| 94 | + rwdt_wait_cycles(priv, 2); |
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| 87 | 95 | |
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| 88 | 96 | rwdt_init_timeout(wdev); |
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| 89 | 97 | rwdt_write(priv, priv->cks, RWTCSRA); |
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| .. | .. |
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| 102 | 110 | struct rwdt_priv *priv = watchdog_get_drvdata(wdev); |
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| 103 | 111 | |
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| 104 | 112 | rwdt_write(priv, priv->cks, RWTCSRA); |
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| 113 | + /* Delay 3 cycles before disabling module clock */ |
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| 114 | + rwdt_wait_cycles(priv, 3); |
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| 105 | 115 | pm_runtime_put(wdev->parent); |
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| 106 | 116 | |
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| 107 | 117 | return 0; |
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| .. | .. |
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| 155 | 165 | .data = (void *)1, /* needs single CPU */ |
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| 156 | 166 | }, { |
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| 157 | 167 | .soc_id = "r8a7792", |
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| 158 | | - .revision = "*", |
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| 159 | 168 | .data = (void *)0, /* needs SMP disabled */ |
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| 160 | 169 | }, |
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| 161 | 170 | { /* sentinel */ } |
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| .. | .. |
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| 180 | 189 | |
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| 181 | 190 | static int rwdt_probe(struct platform_device *pdev) |
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| 182 | 191 | { |
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| 192 | + struct device *dev = &pdev->dev; |
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| 183 | 193 | struct rwdt_priv *priv; |
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| 184 | | - struct resource *res; |
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| 185 | 194 | struct clk *clk; |
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| 186 | 195 | unsigned long clks_per_sec; |
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| 187 | 196 | int ret, i; |
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| 197 | + u8 csra; |
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| 188 | 198 | |
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| 189 | | - if (rwdt_blacklisted(&pdev->dev)) |
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| 199 | + if (rwdt_blacklisted(dev)) |
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| 190 | 200 | return -ENODEV; |
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| 191 | 201 | |
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| 192 | | - priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
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| 202 | + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); |
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| 193 | 203 | if (!priv) |
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| 194 | 204 | return -ENOMEM; |
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| 195 | 205 | |
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| 196 | | - res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
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| 197 | | - priv->base = devm_ioremap_resource(&pdev->dev, res); |
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| 206 | + priv->base = devm_platform_ioremap_resource(pdev, 0); |
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| 198 | 207 | if (IS_ERR(priv->base)) |
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| 199 | 208 | return PTR_ERR(priv->base); |
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| 200 | 209 | |
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| 201 | | - clk = devm_clk_get(&pdev->dev, NULL); |
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| 210 | + clk = devm_clk_get(dev, NULL); |
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| 202 | 211 | if (IS_ERR(clk)) |
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| 203 | 212 | return PTR_ERR(clk); |
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| 204 | 213 | |
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| 205 | | - pm_runtime_enable(&pdev->dev); |
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| 206 | | - pm_runtime_get_sync(&pdev->dev); |
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| 214 | + pm_runtime_enable(dev); |
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| 215 | + pm_runtime_get_sync(dev); |
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| 207 | 216 | priv->clk_rate = clk_get_rate(clk); |
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| 208 | | - priv->wdev.bootstatus = (readb_relaxed(priv->base + RWTCSRA) & |
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| 209 | | - RWTCSRA_WOVF) ? WDIOF_CARDRESET : 0; |
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| 210 | | - pm_runtime_put(&pdev->dev); |
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| 217 | + csra = readb_relaxed(priv->base + RWTCSRA); |
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| 218 | + priv->wdev.bootstatus = csra & RWTCSRA_WOVF ? WDIOF_CARDRESET : 0; |
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| 219 | + pm_runtime_put(dev); |
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| 211 | 220 | |
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| 212 | 221 | if (!priv->clk_rate) { |
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| 213 | 222 | ret = -ENOENT; |
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| .. | .. |
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| 223 | 232 | } |
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| 224 | 233 | |
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| 225 | 234 | if (i < 0) { |
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| 226 | | - dev_err(&pdev->dev, "Can't find suitable clock divider\n"); |
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| 235 | + dev_err(dev, "Can't find suitable clock divider\n"); |
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| 227 | 236 | ret = -ERANGE; |
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| 228 | 237 | goto out_pm_disable; |
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| 229 | 238 | } |
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| 230 | 239 | |
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| 231 | | - priv->wdev.info = &rwdt_ident, |
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| 232 | | - priv->wdev.ops = &rwdt_ops, |
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| 233 | | - priv->wdev.parent = &pdev->dev; |
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| 240 | + priv->wdev.info = &rwdt_ident; |
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| 241 | + priv->wdev.ops = &rwdt_ops; |
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| 242 | + priv->wdev.parent = dev; |
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| 234 | 243 | priv->wdev.min_timeout = 1; |
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| 235 | 244 | priv->wdev.max_timeout = DIV_BY_CLKS_PER_SEC(priv, 65536); |
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| 236 | 245 | priv->wdev.timeout = min(priv->wdev.max_timeout, RWDT_DEFAULT_TIMEOUT); |
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| .. | .. |
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| 242 | 251 | watchdog_stop_on_unregister(&priv->wdev); |
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| 243 | 252 | |
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| 244 | 253 | /* This overrides the default timeout only if DT configuration was found */ |
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| 245 | | - ret = watchdog_init_timeout(&priv->wdev, 0, &pdev->dev); |
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| 246 | | - if (ret) |
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| 247 | | - dev_warn(&pdev->dev, "Specified timeout value invalid, using default\n"); |
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| 254 | + watchdog_init_timeout(&priv->wdev, 0, dev); |
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| 255 | + |
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| 256 | + /* Check if FW enabled the watchdog */ |
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| 257 | + if (csra & RWTCSRA_TME) { |
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| 258 | + /* Ensure properly initialized dividers */ |
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| 259 | + rwdt_start(&priv->wdev); |
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| 260 | + set_bit(WDOG_HW_RUNNING, &priv->wdev.status); |
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| 261 | + } |
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| 248 | 262 | |
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| 249 | 263 | ret = watchdog_register_device(&priv->wdev); |
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| 250 | 264 | if (ret < 0) |
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| .. | .. |
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| 253 | 267 | return 0; |
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| 254 | 268 | |
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| 255 | 269 | out_pm_disable: |
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| 256 | | - pm_runtime_disable(&pdev->dev); |
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| 270 | + pm_runtime_disable(dev); |
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| 257 | 271 | return ret; |
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| 258 | 272 | } |
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| 259 | 273 | |
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| .. | .. |
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| 271 | 285 | { |
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| 272 | 286 | struct rwdt_priv *priv = dev_get_drvdata(dev); |
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| 273 | 287 | |
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| 274 | | - if (watchdog_active(&priv->wdev)) { |
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| 275 | | - priv->time_left = readw(priv->base + RWTCNT); |
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| 288 | + if (watchdog_active(&priv->wdev)) |
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| 276 | 289 | rwdt_stop(&priv->wdev); |
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| 277 | | - } |
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| 290 | + |
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| 278 | 291 | return 0; |
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| 279 | 292 | } |
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| 280 | 293 | |
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| .. | .. |
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| 282 | 295 | { |
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| 283 | 296 | struct rwdt_priv *priv = dev_get_drvdata(dev); |
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| 284 | 297 | |
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| 285 | | - if (watchdog_active(&priv->wdev)) { |
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| 298 | + if (watchdog_active(&priv->wdev)) |
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| 286 | 299 | rwdt_start(&priv->wdev); |
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| 287 | | - rwdt_write(priv, priv->time_left, RWTCNT); |
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| 288 | | - } |
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| 300 | + |
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| 289 | 301 | return 0; |
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| 290 | 302 | } |
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| 291 | 303 | |
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