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_URSTIEN BIT(4) /* User Reset Interrupt Enable */ 39 #define AT91_RSTC_ERSTL GENMASK(11, 8) /* External Reset Length */ 40 41 enum reset_type { 42 RESET_TYPE_GENERAL = 0, 43 RESET_TYPE_WAKEUP = 1, 44 RESET_TYPE_WATCHDOG = 2, 45 RESET_TYPE_SOFTWARE = 3, 46 RESET_TYPE_USER = 4, 47 }; 48 49 static void __iomem *at91_ramc_base[2], *at91_rstc_base; 50 static struct clk *sclk; 51 52 /* 53 * unless the SDRAM is cleanly shutdown before we hit the 54 * reset register it can be left driving the data bus and 55 * killing the chance of a subsequent boot from NAND 56 */ 57 static int at91sam9260_restart(struct notifier_block *this, unsigned long mode, 58 void *cmd) 59 { 60 asm volatile( 61 /* Align to cache lines */ 62 ".balign 32\n\t" 63 64 /* Disable SDRAM accesses */ 65 "str %2, [%0, #" __stringify(AT91_SDRAMC_TR) "]\n\t" 66 67 /* Power down SDRAM */ 68 "str %3, [%0, #" __stringify(AT91_SDRAMC_LPR) "]\n\t" 69 70 /* Reset CPU */ 71 "str %4, [%1, #" __stringify(AT91_RSTC_CR) "]\n\t" 72 73 "b .\n\t" 74 : 75 : "r" (at91_ramc_base[0]), 76 "r" (at91_rstc_base), 77 "r" (1), 78 "r" cpu_to_le32(AT91_SDRAMC_LPCB_POWER_DOWN), 79 "r" cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST)); 80 81 return NOTIFY_DONE; 82 } 83 84 static int at91sam9g45_restart(struct notifier_block *this, unsigned long mode, 85 void *cmd) 86 { 87 asm volatile( 88 /* 89 * Test wether we have a second RAM controller to care 90 * about. 91 * 92 * First, test that we can dereference the virtual address. 93 */ 94 "cmp %1, #0\n\t" 95 "beq 1f\n\t" 96 97 /* Then, test that the RAM controller is enabled */ 98 "ldr r0, [%1]\n\t" 99 "cmp r0, #0\n\t" 100 101 /* Align to cache lines */ 102 ".balign 32\n\t" 103 104 /* Disable SDRAM0 accesses */ 105 "1: str %3, [%0, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t" 106 /* Power down SDRAM0 */ 107 " str %4, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t" 108 /* Disable SDRAM1 accesses */ 109 " strne %3, [%1, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t" 110 /* Power down SDRAM1 */ 111 " strne %4, [%1, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t" 112 /* Reset CPU */ 113 " str %5, [%2, #" __stringify(AT91_RSTC_CR) "]\n\t" 114 115 " b .\n\t" 116 : 117 : "r" (at91_ramc_base[0]), 118 "r" (at91_ramc_base[1]), 119 "r" (at91_rstc_base), 120 "r" (1), 121 "r" cpu_to_le32(AT91_DDRSDRC_LPCB_POWER_DOWN), 122 "r" cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST) 123 : "r0"); 124 125 return NOTIFY_DONE; 126 } 127 128 static int sama5d3_restart(struct notifier_block *this, unsigned long mode, 129 void *cmd) 130 { 131 writel(cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST), 132 at91_rstc_base); 133 134 return NOTIFY_DONE; 135 } 136 137 static int samx7_restart(struct notifier_block *this, unsigned long mode, 138 void *cmd) 139 { 140 writel(cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PROCRST), 141 at91_rstc_base); 142 143 return NOTIFY_DONE; 144 } 145 146 static void __init at91_reset_status(struct platform_device *pdev) 147 { 148 const char *reason; 149 u32 reg = readl(at91_rstc_base + AT91_RSTC_SR); 150 151 switch ((reg & AT91_RSTC_RSTTYP) >> 8) { 152 case RESET_TYPE_GENERAL: 153 reason = "general reset"; 154 break; 155 case RESET_TYPE_WAKEUP: 156 reason = "wakeup"; 157 break; 158 case RESET_TYPE_WATCHDOG: 159 reason = "watchdog reset"; 160 break; 161 case RESET_TYPE_SOFTWARE: 162 reason = "software reset"; 163 break; 164 case RESET_TYPE_USER: 165 reason = "user reset"; 166 break; 167 default: 168 reason = "unknown reset"; 169 break; 170 } 171 172 dev_info(&pdev->dev, "Starting after %s\n", reason); 173 } 174 175 static const struct of_device_id at91_ramc_of_match[] = { 176 { .compatible = "atmel,at91sam9260-sdramc", }, 177 { .compatible = "atmel,at91sam9g45-ddramc", }, 178 { /* sentinel */ } 179 }; 180 181 static const struct of_device_id at91_reset_of_match[] = { 182 { .compatible = "atmel,at91sam9260-rstc", .data = at91sam9260_restart }, 183 { .compatible = "atmel,at91sam9g45-rstc", .data = at91sam9g45_restart }, 184 { .compatible = "atmel,sama5d3-rstc", .data = sama5d3_restart }, 185 { .compatible = "atmel,samx7-rstc", .data = samx7_restart }, 186 { /* sentinel */ } 187 }; 188 MODULE_DEVICE_TABLE(of, at91_reset_of_match); 189 190 static struct notifier_block at91_restart_nb = { 191 .priority = 192, 192 }; 193 194 static int __init at91_reset_probe(struct platform_device *pdev) 195 { 196 const struct of_device_id *match; 197 struct device_node *np; 198 int ret, idx = 0; 199 200 at91_rstc_base = of_iomap(pdev->dev.of_node, 0); 201 if (!at91_rstc_base) { 202 dev_err(&pdev->dev, "Could not map reset controller address\n"); 203 return -ENODEV; 204 } 205 206 if (!of_device_is_compatible(pdev->dev.of_node, "atmel,sama5d3-rstc")) { 207 /* we need to shutdown the ddr controller, so get ramc base */ 208 for_each_matching_node(np, at91_ramc_of_match) { 209 at91_ramc_base[idx] = of_iomap(np, 0); 210 if (!at91_ramc_base[idx]) { 211 dev_err(&pdev->dev, "Could not map ram controller address\n"); 212 of_node_put(np); 213 return -ENODEV; 214 } 215 idx++; 216 } 217 } 218 219 match = of_match_node(at91_reset_of_match, pdev->dev.of_node); 220 at91_restart_nb.notifier_call = match->data; 221 222 sclk = devm_clk_get(&pdev->dev, NULL); 223 if (IS_ERR(sclk)) 224 return PTR_ERR(sclk); 225 226 ret = clk_prepare_enable(sclk); 227 if (ret) { 228 dev_err(&pdev->dev, "Could not enable slow clock\n"); 229 return ret; 230 } 231 232 ret = register_restart_handler(&at91_restart_nb); 233 if (ret) { 234 clk_disable_unprepare(sclk); 235 return ret; 236 } 237 238 at91_reset_status(pdev); 239 240 return 0; 241 } 242 243 static int __exit at91_reset_remove(struct platform_device *pdev) 244 { 245 unregister_restart_handler(&at91_restart_nb); 246 clk_disable_unprepare(sclk); 247 248 return 0; 249 } 250 251 static struct platform_driver at91_reset_driver = { 252 .remove = __exit_p(at91_reset_remove), 253 .driver = { 254 .name = "at91-reset", 255 .of_match_table = at91_reset_of_match, 256 }, 257 }; 258 module_platform_driver_probe(at91_reset_driver, at91_reset_probe); 259 260 MODULE_AUTHOR("Atmel Corporation"); 261 MODULE_DESCRIPTION("Reset driver for Atmel SoCs"); 262 MODULE_LICENSE("GPL v2"); 263