1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Renesas RZ/G2L WDT Watchdog Driver 4 * 5 * Copyright (C) 2021 Renesas Electronics Corporation 6 */ 7 #include <linux/bitops.h> 8 #include <linux/clk.h> 9 #include <linux/delay.h> 10 #include <linux/io.h> 11 #include <linux/iopoll.h> 12 #include <linux/kernel.h> 13 #include <linux/module.h> 14 #include <linux/of.h> 15 #include <linux/platform_device.h> 16 #include <linux/pm_runtime.h> 17 #include <linux/reset.h> 18 #include <linux/units.h> 19 #include <linux/watchdog.h> 20 21 #define WDTCNT 0x00 22 #define WDTSET 0x04 23 #define WDTTIM 0x08 24 #define WDTINT 0x0C 25 #define PECR 0x10 26 #define PEEN 0x14 27 #define WDTCNT_WDTEN BIT(0) 28 #define WDTINT_INTDISP BIT(0) 29 #define PEEN_FORCE BIT(0) 30 31 #define WDT_DEFAULT_TIMEOUT 60U 32 33 /* Setting period time register only 12 bit set in WDTSET[31:20] */ 34 #define WDTSET_COUNTER_MASK (0xFFF00000) 35 #define WDTSET_COUNTER_VAL(f) ((f) << 20) 36 37 #define F2CYCLE_NSEC(f) (1000000000 / (f)) 38 39 #define RZV2M_A_NSEC 730 40 41 static bool nowayout = WATCHDOG_NOWAYOUT; 42 module_param(nowayout, bool, 0); 43 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 44 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 45 46 enum rz_wdt_type { 47 WDT_RZG2L, 48 WDT_RZV2M, 49 }; 50 51 struct rzg2l_wdt_priv { 52 void __iomem *base; 53 struct watchdog_device wdev; 54 struct reset_control *rstc; 55 unsigned long osc_clk_rate; 56 unsigned long delay; 57 unsigned long minimum_assertion_period; 58 struct clk *pclk; 59 struct clk *osc_clk; 60 enum rz_wdt_type devtype; 61 }; 62 63 static int rzg2l_wdt_reset(struct rzg2l_wdt_priv *priv) 64 { 65 int err, status; 66 67 if (priv->devtype == WDT_RZV2M) { 68 /* WDT needs TYPE-B reset control */ 69 err = reset_control_assert(priv->rstc); 70 if (err) 71 return err; 72 ndelay(priv->minimum_assertion_period); 73 err = reset_control_deassert(priv->rstc); 74 if (err) 75 return err; 76 err = read_poll_timeout(reset_control_status, status, 77 status != 1, 0, 1000, false, 78 priv->rstc); 79 } else { 80 err = reset_control_reset(priv->rstc); 81 } 82 83 return err; 84 } 85 86 static void rzg2l_wdt_wait_delay(struct rzg2l_wdt_priv *priv) 87 { 88 /* delay timer when change the setting register */ 89 ndelay(priv->delay); 90 } 91 92 static u32 rzg2l_wdt_get_cycle_usec(unsigned long cycle, u32 wdttime) 93 { 94 u64 timer_cycle_us = 1024 * 1024ULL * (wdttime + 1) * MICRO; 95 96 return div64_ul(timer_cycle_us, cycle); 97 } 98 99 static void rzg2l_wdt_write(struct rzg2l_wdt_priv *priv, u32 val, unsigned int reg) 100 { 101 if (reg == WDTSET) 102 val &= WDTSET_COUNTER_MASK; 103 104 writel_relaxed(val, priv->base + reg); 105 /* Registers other than the WDTINT is always synchronized with WDT_CLK */ 106 if (reg != WDTINT) 107 rzg2l_wdt_wait_delay(priv); 108 } 109 110 static void rzg2l_wdt_init_timeout(struct watchdog_device *wdev) 111 { 112 struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev); 113 u32 time_out; 114 115 /* Clear Lapsed Time Register and clear Interrupt */ 116 rzg2l_wdt_write(priv, WDTINT_INTDISP, WDTINT); 117 /* 2 consecutive overflow cycle needed to trigger reset */ 118 time_out = (wdev->timeout * (MICRO / 2)) / 119 rzg2l_wdt_get_cycle_usec(priv->osc_clk_rate, 0); 120 rzg2l_wdt_write(priv, WDTSET_COUNTER_VAL(time_out), WDTSET); 121 } 122 123 static int rzg2l_wdt_start(struct watchdog_device *wdev) 124 { 125 struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev); 126 127 pm_runtime_get_sync(wdev->parent); 128 129 /* Initialize time out */ 130 rzg2l_wdt_init_timeout(wdev); 131 132 /* Initialize watchdog counter register */ 133 rzg2l_wdt_write(priv, 0, WDTTIM); 134 135 /* Enable watchdog timer*/ 136 rzg2l_wdt_write(priv, WDTCNT_WDTEN, WDTCNT); 137 138 return 0; 139 } 140 141 static int rzg2l_wdt_stop(struct watchdog_device *wdev) 142 { 143 struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev); 144 145 rzg2l_wdt_reset(priv); 146 pm_runtime_put(wdev->parent); 147 148 return 0; 149 } 150 151 static int rzg2l_wdt_set_timeout(struct watchdog_device *wdev, unsigned int timeout) 152 { 153 wdev->timeout = timeout; 154 155 /* 156 * If the watchdog is active, reset the module for updating the WDTSET 157 * register by calling rzg2l_wdt_stop() (which internally calls reset_control_reset() 158 * to reset the module) so that it is updated with new timeout values. 159 */ 160 if (watchdog_active(wdev)) { 161 rzg2l_wdt_stop(wdev); 162 rzg2l_wdt_start(wdev); 163 } 164 165 return 0; 166 } 167 168 static int rzg2l_wdt_restart(struct watchdog_device *wdev, 169 unsigned long action, void *data) 170 { 171 struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev); 172 173 clk_prepare_enable(priv->pclk); 174 clk_prepare_enable(priv->osc_clk); 175 176 if (priv->devtype == WDT_RZG2L) { 177 /* Generate Reset (WDTRSTB) Signal on parity error */ 178 rzg2l_wdt_write(priv, 0, PECR); 179 180 /* Force parity error */ 181 rzg2l_wdt_write(priv, PEEN_FORCE, PEEN); 182 } else { 183 /* RZ/V2M doesn't have parity error registers */ 184 rzg2l_wdt_reset(priv); 185 186 wdev->timeout = 0; 187 188 /* Initialize time out */ 189 rzg2l_wdt_init_timeout(wdev); 190 191 /* Initialize watchdog counter register */ 192 rzg2l_wdt_write(priv, 0, WDTTIM); 193 194 /* Enable watchdog timer*/ 195 rzg2l_wdt_write(priv, WDTCNT_WDTEN, WDTCNT); 196 197 /* Wait 2 consecutive overflow cycles for reset */ 198 mdelay(DIV_ROUND_UP(2 * 0xFFFFF * 1000, priv->osc_clk_rate)); 199 } 200 201 return 0; 202 } 203 204 static const struct watchdog_info rzg2l_wdt_ident = { 205 .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, 206 .identity = "Renesas RZ/G2L WDT Watchdog", 207 }; 208 209 static int rzg2l_wdt_ping(struct watchdog_device *wdev) 210 { 211 struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev); 212 213 rzg2l_wdt_write(priv, WDTINT_INTDISP, WDTINT); 214 215 return 0; 216 } 217 218 static const struct watchdog_ops rzg2l_wdt_ops = { 219 .owner = THIS_MODULE, 220 .start = rzg2l_wdt_start, 221 .stop = rzg2l_wdt_stop, 222 .ping = rzg2l_wdt_ping, 223 .set_timeout = rzg2l_wdt_set_timeout, 224 .restart = rzg2l_wdt_restart, 225 }; 226 227 static void rzg2l_wdt_reset_assert_pm_disable(void *data) 228 { 229 struct watchdog_device *wdev = data; 230 struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev); 231 232 pm_runtime_disable(wdev->parent); 233 reset_control_assert(priv->rstc); 234 } 235 236 static int rzg2l_wdt_probe(struct platform_device *pdev) 237 { 238 struct device *dev = &pdev->dev; 239 struct rzg2l_wdt_priv *priv; 240 unsigned long pclk_rate; 241 int ret; 242 243 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 244 if (!priv) 245 return -ENOMEM; 246 247 priv->base = devm_platform_ioremap_resource(pdev, 0); 248 if (IS_ERR(priv->base)) 249 return PTR_ERR(priv->base); 250 251 /* Get watchdog main clock */ 252 priv->osc_clk = devm_clk_get(&pdev->dev, "oscclk"); 253 if (IS_ERR(priv->osc_clk)) 254 return dev_err_probe(&pdev->dev, PTR_ERR(priv->osc_clk), "no oscclk"); 255 256 priv->osc_clk_rate = clk_get_rate(priv->osc_clk); 257 if (!priv->osc_clk_rate) 258 return dev_err_probe(&pdev->dev, -EINVAL, "oscclk rate is 0"); 259 260 /* Get Peripheral clock */ 261 priv->pclk = devm_clk_get(&pdev->dev, "pclk"); 262 if (IS_ERR(priv->pclk)) 263 return dev_err_probe(&pdev->dev, PTR_ERR(priv->pclk), "no pclk"); 264 265 pclk_rate = clk_get_rate(priv->pclk); 266 if (!pclk_rate) 267 return dev_err_probe(&pdev->dev, -EINVAL, "pclk rate is 0"); 268 269 priv->delay = F2CYCLE_NSEC(priv->osc_clk_rate) * 6 + F2CYCLE_NSEC(pclk_rate) * 9; 270 271 priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL); 272 if (IS_ERR(priv->rstc)) 273 return dev_err_probe(&pdev->dev, PTR_ERR(priv->rstc), 274 "failed to get cpg reset"); 275 276 ret = reset_control_deassert(priv->rstc); 277 if (ret) 278 return dev_err_probe(dev, ret, "failed to deassert"); 279 280 priv->devtype = (uintptr_t)of_device_get_match_data(dev); 281 282 if (priv->devtype == WDT_RZV2M) { 283 priv->minimum_assertion_period = RZV2M_A_NSEC + 284 3 * F2CYCLE_NSEC(pclk_rate) + 5 * 285 max(F2CYCLE_NSEC(priv->osc_clk_rate), 286 F2CYCLE_NSEC(pclk_rate)); 287 } 288 289 pm_runtime_enable(&pdev->dev); 290 291 priv->wdev.info = &rzg2l_wdt_ident; 292 priv->wdev.ops = &rzg2l_wdt_ops; 293 priv->wdev.parent = dev; 294 priv->wdev.min_timeout = 1; 295 priv->wdev.max_timeout = rzg2l_wdt_get_cycle_usec(priv->osc_clk_rate, 0xfff) / 296 USEC_PER_SEC; 297 priv->wdev.timeout = WDT_DEFAULT_TIMEOUT; 298 299 watchdog_set_drvdata(&priv->wdev, priv); 300 ret = devm_add_action_or_reset(&pdev->dev, 301 rzg2l_wdt_reset_assert_pm_disable, 302 &priv->wdev); 303 if (ret < 0) 304 return ret; 305 306 watchdog_set_nowayout(&priv->wdev, nowayout); 307 watchdog_stop_on_unregister(&priv->wdev); 308 309 ret = watchdog_init_timeout(&priv->wdev, 0, dev); 310 if (ret) 311 dev_warn(dev, "Specified timeout invalid, using default"); 312 313 return devm_watchdog_register_device(&pdev->dev, &priv->wdev); 314 } 315 316 static const struct of_device_id rzg2l_wdt_ids[] = { 317 { .compatible = "renesas,rzg2l-wdt", .data = (void *)WDT_RZG2L }, 318 { .compatible = "renesas,rzv2m-wdt", .data = (void *)WDT_RZV2M }, 319 { /* sentinel */ } 320 }; 321 MODULE_DEVICE_TABLE(of, rzg2l_wdt_ids); 322 323 static struct platform_driver rzg2l_wdt_driver = { 324 .driver = { 325 .name = "rzg2l_wdt", 326 .of_match_table = rzg2l_wdt_ids, 327 }, 328 .probe = rzg2l_wdt_probe, 329 }; 330 module_platform_driver(rzg2l_wdt_driver); 331 332 MODULE_DESCRIPTION("Renesas RZ/G2L WDT Watchdog Driver"); 333 MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>"); 334 MODULE_LICENSE("GPL v2"); 335