1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Xilinx SLCR driver 4 * 5 * Copyright (c) 2011-2013 Xilinx Inc. 6 */ 7 8 #include <linux/io.h> 9 #include <linux/reboot.h> 10 #include <linux/mfd/syscon.h> 11 #include <linux/of_address.h> 12 #include <linux/regmap.h> 13 #include <linux/clk/zynq.h> 14 #include "common.h" 15 16 /* register offsets */ 17 #define SLCR_UNLOCK_OFFSET 0x8 /* SCLR unlock register */ 18 #define SLCR_PS_RST_CTRL_OFFSET 0x200 /* PS Software Reset Control */ 19 #define SLCR_A9_CPU_RST_CTRL_OFFSET 0x244 /* CPU Software Reset Control */ 20 #define SLCR_REBOOT_STATUS_OFFSET 0x258 /* PS Reboot Status */ 21 #define SLCR_PSS_IDCODE 0x530 /* PS IDCODE */ 22 #define SLCR_L2C_RAM 0xA1C /* L2C_RAM in AR#54190 */ 23 24 #define SLCR_UNLOCK_MAGIC 0xDF0D 25 #define SLCR_A9_CPU_CLKSTOP 0x10 26 #define SLCR_A9_CPU_RST 0x1 27 #define SLCR_PSS_IDCODE_DEVICE_SHIFT 12 28 #define SLCR_PSS_IDCODE_DEVICE_MASK 0x1F 29 30 static void __iomem *zynq_slcr_base; 31 static struct regmap *zynq_slcr_regmap; 32 33 /** 34 * zynq_slcr_write - Write to a register in SLCR block 35 * 36 * @val: Value to write to the register 37 * @offset: Register offset in SLCR block 38 * 39 * Return: a negative value on error, 0 on success 40 */ 41 static int zynq_slcr_write(u32 val, u32 offset) 42 { 43 return regmap_write(zynq_slcr_regmap, offset, val); 44 } 45 46 /** 47 * zynq_slcr_read - Read a register in SLCR block 48 * 49 * @val: Pointer to value to be read from SLCR 50 * @offset: Register offset in SLCR block 51 * 52 * Return: a negative value on error, 0 on success 53 */ 54 static int zynq_slcr_read(u32 *val, u32 offset) 55 { 56 return regmap_read(zynq_slcr_regmap, offset, val); 57 } 58 59 /** 60 * zynq_slcr_unlock - Unlock SLCR registers 61 * 62 * Return: a negative value on error, 0 on success 63 */ 64 static inline int zynq_slcr_unlock(void) 65 { 66 zynq_slcr_write(SLCR_UNLOCK_MAGIC, SLCR_UNLOCK_OFFSET); 67 68 return 0; 69 } 70 71 /** 72 * zynq_slcr_get_device_id - Read device code id 73 * 74 * Return: Device code id 75 */ 76 u32 zynq_slcr_get_device_id(void) 77 { 78 u32 val; 79 80 zynq_slcr_read(&val, SLCR_PSS_IDCODE); 81 val >>= SLCR_PSS_IDCODE_DEVICE_SHIFT; 82 val &= SLCR_PSS_IDCODE_DEVICE_MASK; 83 84 return val; 85 } 86 87 /** 88 * zynq_slcr_system_restart - Restart the entire system. 89 * 90 * @nb: Pointer to restart notifier block (unused) 91 * @action: Reboot mode (unused) 92 * @data: Restart handler private data (unused) 93 * 94 * Return: 0 always 95 */ 96 static 97 int zynq_slcr_system_restart(struct notifier_block *nb, 98 unsigned long action, void *data) 99 { 100 u32 reboot; 101 102 /* 103 * Clear 0x0F000000 bits of reboot status register to workaround 104 * the FSBL not loading the bitstream after soft-reboot 105 * This is a temporary solution until we know more. 106 */ 107 zynq_slcr_read(&reboot, SLCR_REBOOT_STATUS_OFFSET); 108 zynq_slcr_write(reboot & 0xF0FFFFFF, SLCR_REBOOT_STATUS_OFFSET); 109 zynq_slcr_write(1, SLCR_PS_RST_CTRL_OFFSET); 110 return 0; 111 } 112 113 static struct notifier_block zynq_slcr_restart_nb = { 114 .notifier_call = zynq_slcr_system_restart, 115 .priority = 192, 116 }; 117 118 /** 119 * zynq_slcr_cpu_start - Start cpu 120 * @cpu: cpu number 121 */ 122 void zynq_slcr_cpu_start(int cpu) 123 { 124 u32 reg; 125 126 zynq_slcr_read(®, SLCR_A9_CPU_RST_CTRL_OFFSET); 127 reg &= ~(SLCR_A9_CPU_RST << cpu); 128 zynq_slcr_write(reg, SLCR_A9_CPU_RST_CTRL_OFFSET); 129 reg &= ~(SLCR_A9_CPU_CLKSTOP << cpu); 130 zynq_slcr_write(reg, SLCR_A9_CPU_RST_CTRL_OFFSET); 131 132 zynq_slcr_cpu_state_write(cpu, false); 133 } 134 135 /** 136 * zynq_slcr_cpu_stop - Stop cpu 137 * @cpu: cpu number 138 */ 139 void zynq_slcr_cpu_stop(int cpu) 140 { 141 u32 reg; 142 143 zynq_slcr_read(®, SLCR_A9_CPU_RST_CTRL_OFFSET); 144 reg |= (SLCR_A9_CPU_CLKSTOP | SLCR_A9_CPU_RST) << cpu; 145 zynq_slcr_write(reg, SLCR_A9_CPU_RST_CTRL_OFFSET); 146 } 147 148 /** 149 * zynq_slcr_cpu_state - Read/write cpu state 150 * @cpu: cpu number 151 * 152 * SLCR_REBOOT_STATUS save upper 2 bits (31/30 cpu states for cpu0 and cpu1) 153 * 0 means cpu is running, 1 cpu is going to die. 154 * 155 * Return: true if cpu is running, false if cpu is going to die 156 */ 157 bool zynq_slcr_cpu_state_read(int cpu) 158 { 159 u32 state; 160 161 state = readl(zynq_slcr_base + SLCR_REBOOT_STATUS_OFFSET); 162 state &= 1 << (31 - cpu); 163 164 return !state; 165 } 166 167 /** 168 * zynq_slcr_cpu_state - Read/write cpu state 169 * @cpu: cpu number 170 * @die: cpu state - true if cpu is going to die 171 * 172 * SLCR_REBOOT_STATUS save upper 2 bits (31/30 cpu states for cpu0 and cpu1) 173 * 0 means cpu is running, 1 cpu is going to die. 174 */ 175 void zynq_slcr_cpu_state_write(int cpu, bool die) 176 { 177 u32 state, mask; 178 179 state = readl(zynq_slcr_base + SLCR_REBOOT_STATUS_OFFSET); 180 mask = 1 << (31 - cpu); 181 if (die) 182 state |= mask; 183 else 184 state &= ~mask; 185 writel(state, zynq_slcr_base + SLCR_REBOOT_STATUS_OFFSET); 186 } 187 188 /** 189 * zynq_early_slcr_init - Early slcr init function 190 * 191 * Return: 0 on success, negative errno otherwise. 192 * 193 * Called very early during boot from platform code to unlock SLCR. 194 */ 195 int __init zynq_early_slcr_init(void) 196 { 197 struct device_node *np; 198 199 np = of_find_compatible_node(NULL, NULL, "xlnx,zynq-slcr"); 200 if (!np) { 201 pr_err("%s: no slcr node found\n", __func__); 202 BUG(); 203 } 204 205 zynq_slcr_base = of_iomap(np, 0); 206 if (!zynq_slcr_base) { 207 pr_err("%s: Unable to map I/O memory\n", __func__); 208 BUG(); 209 } 210 211 np->data = (__force void *)zynq_slcr_base; 212 213 zynq_slcr_regmap = syscon_regmap_lookup_by_compatible("xlnx,zynq-slcr"); 214 if (IS_ERR(zynq_slcr_regmap)) { 215 pr_err("%s: failed to find zynq-slcr\n", __func__); 216 of_node_put(np); 217 return -ENODEV; 218 } 219 220 /* unlock the SLCR so that registers can be changed */ 221 zynq_slcr_unlock(); 222 223 /* See AR#54190 design advisory */ 224 regmap_update_bits(zynq_slcr_regmap, SLCR_L2C_RAM, 0x70707, 0x20202); 225 226 register_restart_handler(&zynq_slcr_restart_nb); 227 228 pr_info("%pOFn mapped to %p\n", np, zynq_slcr_base); 229 230 of_node_put(np); 231 232 return 0; 233 } 234