1 /* 2 * Atmel AT91 SAM9 & SAMA5 SoCs reset code 3 * 4 * Copyright (C) 2007 Atmel Corporation. 5 * Copyright (C) BitBox Ltd 2010 6 * Copyright (C) 2011 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcosoft.com> 7 * Copyright (C) 2014 Free Electrons 8 * 9 * This file is licensed under the terms of the GNU General Public 10 * License version 2. This program is licensed "as is" without any 11 * warranty of any kind, whether express or implied. 12 */ 13 14 #include <linux/clk.h> 15 #include <linux/io.h> 16 #include <linux/module.h> 17 #include <linux/of_address.h> 18 #include <linux/platform_device.h> 19 #include <linux/reboot.h> 20 21 #include <soc/at91/at91sam9_ddrsdr.h> 22 #include <soc/at91/at91sam9_sdramc.h> 23 24 #define AT91_RSTC_CR 0x00 /* Reset Controller Control Register */ 25 #define AT91_RSTC_PROCRST BIT(0) /* Processor Reset */ 26 #define AT91_RSTC_PERRST BIT(2) /* Peripheral Reset */ 27 #define AT91_RSTC_EXTRST BIT(3) /* External Reset */ 28 #define AT91_RSTC_KEY (0xa5 << 24) /* KEY Password */ 29 30 #define AT91_RSTC_SR 0x04 /* Reset Controller Status Register */ 31 #define AT91_RSTC_URSTS BIT(0) /* User Reset Status */ 32 #define AT91_RSTC_RSTTYP GENMASK(10, 8) /* Reset Type */ 33 #define AT91_RSTC_NRSTL BIT(16) /* NRST Pin Level */ 34 #define AT91_RSTC_SRCMP BIT(17) /* Software Reset Command in Progress */ 35 36 #define AT91_RSTC_MR 0x08 /* Reset Controller Mode Register */ 37 #define AT91_RSTC_URSTEN BIT(0) /* User Reset Enable */ 38 #define AT91_RSTC_URSTASYNC BIT(2) /* User Reset Asynchronous Control */ 39 #define AT91_RSTC_URSTIEN BIT(4) /* User Reset Interrupt Enable */ 40 #define AT91_RSTC_ERSTL GENMASK(11, 8) /* External Reset Length */ 41 42 enum reset_type { 43 RESET_TYPE_GENERAL = 0, 44 RESET_TYPE_WAKEUP = 1, 45 RESET_TYPE_WATCHDOG = 2, 46 RESET_TYPE_SOFTWARE = 3, 47 RESET_TYPE_USER = 4, 48 RESET_TYPE_CPU_FAIL = 6, 49 RESET_TYPE_XTAL_FAIL = 7, 50 RESET_TYPE_ULP2 = 8, 51 }; 52 53 struct at91_reset { 54 void __iomem *rstc_base; 55 void __iomem *ramc_base[2]; 56 struct clk *sclk; 57 struct notifier_block nb; 58 u32 args; 59 u32 ramc_lpr; 60 }; 61 62 /* 63 * unless the SDRAM is cleanly shutdown before we hit the 64 * reset register it can be left driving the data bus and 65 * killing the chance of a subsequent boot from NAND 66 */ 67 static int at91_reset(struct notifier_block *this, unsigned long mode, 68 void *cmd) 69 { 70 struct at91_reset *reset = container_of(this, struct at91_reset, nb); 71 72 asm volatile( 73 /* Align to cache lines */ 74 ".balign 32\n\t" 75 76 /* Disable SDRAM0 accesses */ 77 " tst %0, #0\n\t" 78 " beq 1f\n\t" 79 " str %3, [%0, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t" 80 /* Power down SDRAM0 */ 81 " str %4, [%0, %6]\n\t" 82 /* Disable SDRAM1 accesses */ 83 "1: tst %1, #0\n\t" 84 " beq 2f\n\t" 85 " strne %3, [%1, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t" 86 /* Power down SDRAM1 */ 87 " strne %4, [%1, %6]\n\t" 88 /* Reset CPU */ 89 "2: str %5, [%2, #" __stringify(AT91_RSTC_CR) "]\n\t" 90 91 " b .\n\t" 92 : 93 : "r" (reset->ramc_base[0]), 94 "r" (reset->ramc_base[1]), 95 "r" (reset->rstc_base), 96 "r" (1), 97 "r" cpu_to_le32(AT91_DDRSDRC_LPCB_POWER_DOWN), 98 "r" (reset->args), 99 "r" (reset->ramc_lpr) 100 : "r4"); 101 102 return NOTIFY_DONE; 103 } 104 105 static void __init at91_reset_status(struct platform_device *pdev, 106 void __iomem *base) 107 { 108 const char *reason; 109 u32 reg = readl(base + AT91_RSTC_SR); 110 111 switch ((reg & AT91_RSTC_RSTTYP) >> 8) { 112 case RESET_TYPE_GENERAL: 113 reason = "general reset"; 114 break; 115 case RESET_TYPE_WAKEUP: 116 reason = "wakeup"; 117 break; 118 case RESET_TYPE_WATCHDOG: 119 reason = "watchdog reset"; 120 break; 121 case RESET_TYPE_SOFTWARE: 122 reason = "software reset"; 123 break; 124 case RESET_TYPE_USER: 125 reason = "user reset"; 126 break; 127 case RESET_TYPE_CPU_FAIL: 128 reason = "CPU clock failure detection"; 129 break; 130 case RESET_TYPE_XTAL_FAIL: 131 reason = "32.768 kHz crystal failure detection"; 132 break; 133 case RESET_TYPE_ULP2: 134 reason = "ULP2 reset"; 135 break; 136 default: 137 reason = "unknown reset"; 138 break; 139 } 140 141 dev_info(&pdev->dev, "Starting after %s\n", reason); 142 } 143 144 static const struct of_device_id at91_ramc_of_match[] = { 145 { 146 .compatible = "atmel,at91sam9260-sdramc", 147 .data = (void *)AT91_SDRAMC_LPR, 148 }, 149 { 150 .compatible = "atmel,at91sam9g45-ddramc", 151 .data = (void *)AT91_DDRSDRC_LPR, 152 }, 153 { /* sentinel */ } 154 }; 155 156 static const struct of_device_id at91_reset_of_match[] = { 157 { 158 .compatible = "atmel,at91sam9260-rstc", 159 .data = (void *)(AT91_RSTC_KEY | AT91_RSTC_PERRST | 160 AT91_RSTC_PROCRST), 161 }, 162 { 163 .compatible = "atmel,at91sam9g45-rstc", 164 .data = (void *)(AT91_RSTC_KEY | AT91_RSTC_PERRST | 165 AT91_RSTC_PROCRST) 166 }, 167 { 168 .compatible = "atmel,sama5d3-rstc", 169 .data = (void *)(AT91_RSTC_KEY | AT91_RSTC_PERRST | 170 AT91_RSTC_PROCRST) 171 }, 172 { 173 .compatible = "atmel,samx7-rstc", 174 .data = (void *)(AT91_RSTC_KEY | AT91_RSTC_PROCRST) 175 }, 176 { 177 .compatible = "microchip,sam9x60-rstc", 178 .data = (void *)(AT91_RSTC_KEY | AT91_RSTC_PROCRST) 179 }, 180 { /* sentinel */ } 181 }; 182 MODULE_DEVICE_TABLE(of, at91_reset_of_match); 183 184 static int __init at91_reset_probe(struct platform_device *pdev) 185 { 186 const struct of_device_id *match; 187 struct at91_reset *reset; 188 struct device_node *np; 189 int ret, idx = 0; 190 191 reset = devm_kzalloc(&pdev->dev, sizeof(*reset), GFP_KERNEL); 192 if (!reset) 193 return -ENOMEM; 194 195 reset->rstc_base = devm_of_iomap(&pdev->dev, pdev->dev.of_node, 0, NULL); 196 if (IS_ERR(reset->rstc_base)) { 197 dev_err(&pdev->dev, "Could not map reset controller address\n"); 198 return -ENODEV; 199 } 200 201 if (!of_device_is_compatible(pdev->dev.of_node, "atmel,sama5d3-rstc")) { 202 /* we need to shutdown the ddr controller, so get ramc base */ 203 for_each_matching_node_and_match(np, at91_ramc_of_match, &match) { 204 reset->ramc_lpr = (u32)match->data; 205 reset->ramc_base[idx] = devm_of_iomap(&pdev->dev, np, 0, NULL); 206 if (IS_ERR(reset->ramc_base[idx])) { 207 dev_err(&pdev->dev, "Could not map ram controller address\n"); 208 of_node_put(np); 209 return -ENODEV; 210 } 211 idx++; 212 } 213 } 214 215 match = of_match_node(at91_reset_of_match, pdev->dev.of_node); 216 reset->nb.notifier_call = at91_reset; 217 reset->nb.priority = 192; 218 reset->args = (u32)match->data; 219 220 reset->sclk = devm_clk_get(&pdev->dev, NULL); 221 if (IS_ERR(reset->sclk)) 222 return PTR_ERR(reset->sclk); 223 224 ret = clk_prepare_enable(reset->sclk); 225 if (ret) { 226 dev_err(&pdev->dev, "Could not enable slow clock\n"); 227 return ret; 228 } 229 230 platform_set_drvdata(pdev, reset); 231 232 if (of_device_is_compatible(pdev->dev.of_node, "microchip,sam9x60-rstc")) { 233 u32 val = readl(reset->rstc_base + AT91_RSTC_MR); 234 235 writel(AT91_RSTC_KEY | AT91_RSTC_URSTASYNC | val, 236 reset->rstc_base + AT91_RSTC_MR); 237 } 238 239 ret = register_restart_handler(&reset->nb); 240 if (ret) { 241 clk_disable_unprepare(reset->sclk); 242 return ret; 243 } 244 245 at91_reset_status(pdev, reset->rstc_base); 246 247 return 0; 248 } 249 250 static int __exit at91_reset_remove(struct platform_device *pdev) 251 { 252 struct at91_reset *reset = platform_get_drvdata(pdev); 253 254 unregister_restart_handler(&reset->nb); 255 clk_disable_unprepare(reset->sclk); 256 257 return 0; 258 } 259 260 static struct platform_driver at91_reset_driver = { 261 .remove = __exit_p(at91_reset_remove), 262 .driver = { 263 .name = "at91-reset", 264 .of_match_table = at91_reset_of_match, 265 }, 266 }; 267 module_platform_driver_probe(at91_reset_driver, at91_reset_probe); 268 269 MODULE_AUTHOR("Atmel Corporation"); 270 MODULE_DESCRIPTION("Reset driver for Atmel SoCs"); 271 MODULE_LICENSE("GPL v2"); 272