1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2015 Toradex AG. 4 * 5 * Author: Sanchayan Maity <sanchayan.maity@toradex.com> 6 * 7 * Based on the barebox ocotp driver, 8 * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il> 9 * Orex Computed Radiography 10 */ 11 12 #include <linux/clk.h> 13 #include <linux/delay.h> 14 #include <linux/device.h> 15 #include <linux/io.h> 16 #include <linux/module.h> 17 #include <linux/nvmem-provider.h> 18 #include <linux/of.h> 19 #include <linux/platform_device.h> 20 #include <linux/slab.h> 21 22 /* OCOTP Register Offsets */ 23 #define OCOTP_CTRL_REG 0x00 24 #define OCOTP_CTRL_SET 0x04 25 #define OCOTP_CTRL_CLR 0x08 26 #define OCOTP_TIMING 0x10 27 #define OCOTP_DATA 0x20 28 #define OCOTP_READ_CTRL_REG 0x30 29 #define OCOTP_READ_FUSE_DATA 0x40 30 31 /* OCOTP Register bits and masks */ 32 #define OCOTP_CTRL_WR_UNLOCK 16 33 #define OCOTP_CTRL_WR_UNLOCK_KEY 0x3E77 34 #define OCOTP_CTRL_WR_UNLOCK_MASK GENMASK(31, 16) 35 #define OCOTP_CTRL_ADDR 0 36 #define OCOTP_CTRL_ADDR_MASK GENMASK(6, 0) 37 #define OCOTP_CTRL_RELOAD_SHADOWS BIT(10) 38 #define OCOTP_CTRL_ERR BIT(9) 39 #define OCOTP_CTRL_BUSY BIT(8) 40 41 #define OCOTP_TIMING_STROBE_READ 16 42 #define OCOTP_TIMING_STROBE_READ_MASK GENMASK(21, 16) 43 #define OCOTP_TIMING_RELAX 12 44 #define OCOTP_TIMING_RELAX_MASK GENMASK(15, 12) 45 #define OCOTP_TIMING_STROBE_PROG 0 46 #define OCOTP_TIMING_STROBE_PROG_MASK GENMASK(11, 0) 47 48 #define OCOTP_READ_CTRL_READ_FUSE 0x1 49 50 #define VF610_OCOTP_TIMEOUT 100000 51 52 #define BF(value, field) (((value) << field) & field##_MASK) 53 54 #define DEF_RELAX 20 55 56 static const int base_to_fuse_addr_mappings[][2] = { 57 {0x400, 0x00}, 58 {0x410, 0x01}, 59 {0x420, 0x02}, 60 {0x450, 0x05}, 61 {0x4F0, 0x0F}, 62 {0x600, 0x20}, 63 {0x610, 0x21}, 64 {0x620, 0x22}, 65 {0x630, 0x23}, 66 {0x640, 0x24}, 67 {0x650, 0x25}, 68 {0x660, 0x26}, 69 {0x670, 0x27}, 70 {0x6F0, 0x2F}, 71 {0x880, 0x38}, 72 {0x890, 0x39}, 73 {0x8A0, 0x3A}, 74 {0x8B0, 0x3B}, 75 {0x8C0, 0x3C}, 76 {0x8D0, 0x3D}, 77 {0x8E0, 0x3E}, 78 {0x8F0, 0x3F}, 79 {0xC80, 0x78}, 80 {0xC90, 0x79}, 81 {0xCA0, 0x7A}, 82 {0xCB0, 0x7B}, 83 {0xCC0, 0x7C}, 84 {0xCD0, 0x7D}, 85 {0xCE0, 0x7E}, 86 {0xCF0, 0x7F}, 87 }; 88 89 struct vf610_ocotp { 90 void __iomem *base; 91 struct clk *clk; 92 struct device *dev; 93 struct nvmem_device *nvmem; 94 int timing; 95 }; 96 97 static int vf610_ocotp_wait_busy(void __iomem *base) 98 { 99 int timeout = VF610_OCOTP_TIMEOUT; 100 101 while ((readl(base) & OCOTP_CTRL_BUSY) && --timeout) 102 udelay(10); 103 104 if (!timeout) { 105 writel(OCOTP_CTRL_ERR, base + OCOTP_CTRL_CLR); 106 return -ETIMEDOUT; 107 } 108 109 udelay(10); 110 111 return 0; 112 } 113 114 static int vf610_ocotp_calculate_timing(struct vf610_ocotp *ocotp_dev) 115 { 116 u32 clk_rate; 117 u32 relax, strobe_read, strobe_prog; 118 u32 timing; 119 120 clk_rate = clk_get_rate(ocotp_dev->clk); 121 122 /* Refer section OTP read/write timing parameters in TRM */ 123 relax = clk_rate / (1000000000 / DEF_RELAX) - 1; 124 strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1; 125 strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1; 126 127 timing = BF(relax, OCOTP_TIMING_RELAX); 128 timing |= BF(strobe_read, OCOTP_TIMING_STROBE_READ); 129 timing |= BF(strobe_prog, OCOTP_TIMING_STROBE_PROG); 130 131 return timing; 132 } 133 134 static int vf610_get_fuse_address(int base_addr_offset) 135 { 136 int i; 137 138 for (i = 0; i < ARRAY_SIZE(base_to_fuse_addr_mappings); i++) { 139 if (base_to_fuse_addr_mappings[i][0] == base_addr_offset) 140 return base_to_fuse_addr_mappings[i][1]; 141 } 142 143 return -EINVAL; 144 } 145 146 static int vf610_ocotp_read(void *context, unsigned int offset, 147 void *val, size_t bytes) 148 { 149 struct vf610_ocotp *ocotp = context; 150 void __iomem *base = ocotp->base; 151 u32 reg, *buf = val; 152 int fuse_addr; 153 int ret; 154 155 while (bytes > 0) { 156 fuse_addr = vf610_get_fuse_address(offset); 157 if (fuse_addr > 0) { 158 writel(ocotp->timing, base + OCOTP_TIMING); 159 ret = vf610_ocotp_wait_busy(base + OCOTP_CTRL_REG); 160 if (ret) 161 return ret; 162 163 reg = readl(base + OCOTP_CTRL_REG); 164 reg &= ~OCOTP_CTRL_ADDR_MASK; 165 reg &= ~OCOTP_CTRL_WR_UNLOCK_MASK; 166 reg |= BF(fuse_addr, OCOTP_CTRL_ADDR); 167 writel(reg, base + OCOTP_CTRL_REG); 168 169 writel(OCOTP_READ_CTRL_READ_FUSE, 170 base + OCOTP_READ_CTRL_REG); 171 ret = vf610_ocotp_wait_busy(base + OCOTP_CTRL_REG); 172 if (ret) 173 return ret; 174 175 if (readl(base) & OCOTP_CTRL_ERR) { 176 dev_dbg(ocotp->dev, "Error reading from fuse address %x\n", 177 fuse_addr); 178 writel(OCOTP_CTRL_ERR, base + OCOTP_CTRL_CLR); 179 } 180 181 /* 182 * In case of error, we do not abort and expect to read 183 * 0xBADABADA as mentioned by the TRM. We just read this 184 * value and return. 185 */ 186 *buf = readl(base + OCOTP_READ_FUSE_DATA); 187 } else { 188 *buf = 0; 189 } 190 191 buf++; 192 bytes -= 4; 193 offset += 4; 194 } 195 196 return 0; 197 } 198 199 static struct nvmem_config ocotp_config = { 200 .name = "ocotp", 201 .stride = 4, 202 .word_size = 4, 203 .reg_read = vf610_ocotp_read, 204 }; 205 206 static const struct of_device_id ocotp_of_match[] = { 207 { .compatible = "fsl,vf610-ocotp", }, 208 {/* sentinel */}, 209 }; 210 MODULE_DEVICE_TABLE(of, ocotp_of_match); 211 212 static int vf610_ocotp_probe(struct platform_device *pdev) 213 { 214 struct device *dev = &pdev->dev; 215 struct resource *res; 216 struct vf610_ocotp *ocotp_dev; 217 218 ocotp_dev = devm_kzalloc(dev, sizeof(struct vf610_ocotp), GFP_KERNEL); 219 if (!ocotp_dev) 220 return -ENOMEM; 221 222 ocotp_dev->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res); 223 if (IS_ERR(ocotp_dev->base)) 224 return PTR_ERR(ocotp_dev->base); 225 226 ocotp_dev->clk = devm_clk_get(dev, NULL); 227 if (IS_ERR(ocotp_dev->clk)) { 228 dev_err(dev, "failed getting clock, err = %ld\n", 229 PTR_ERR(ocotp_dev->clk)); 230 return PTR_ERR(ocotp_dev->clk); 231 } 232 ocotp_dev->dev = dev; 233 ocotp_dev->timing = vf610_ocotp_calculate_timing(ocotp_dev); 234 235 ocotp_config.size = resource_size(res); 236 ocotp_config.priv = ocotp_dev; 237 ocotp_config.dev = dev; 238 239 ocotp_dev->nvmem = devm_nvmem_register(dev, &ocotp_config); 240 241 return PTR_ERR_OR_ZERO(ocotp_dev->nvmem); 242 } 243 244 static struct platform_driver vf610_ocotp_driver = { 245 .probe = vf610_ocotp_probe, 246 .driver = { 247 .name = "vf610-ocotp", 248 .of_match_table = ocotp_of_match, 249 }, 250 }; 251 module_platform_driver(vf610_ocotp_driver); 252 MODULE_AUTHOR("Sanchayan Maity <sanchayan.maity@toradex.com>"); 253 MODULE_DESCRIPTION("Vybrid OCOTP driver"); 254 MODULE_LICENSE("GPL v2"); 255