1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Allwinner sunXi SoCs Security ID support. 4 * 5 * Copyright (c) 2013 Oliver Schinagl <oliver@schinagl.nl> 6 * Copyright (C) 2014 Maxime Ripard <maxime.ripard@free-electrons.com> 7 */ 8 9 #include <linux/device.h> 10 #include <linux/io.h> 11 #include <linux/iopoll.h> 12 #include <linux/module.h> 13 #include <linux/nvmem-provider.h> 14 #include <linux/of.h> 15 #include <linux/of_device.h> 16 #include <linux/platform_device.h> 17 #include <linux/slab.h> 18 #include <linux/random.h> 19 20 /* Registers and special values for doing register-based SID readout on H3 */ 21 #define SUN8I_SID_PRCTL 0x40 22 #define SUN8I_SID_RDKEY 0x60 23 24 #define SUN8I_SID_OFFSET_MASK 0x1FF 25 #define SUN8I_SID_OFFSET_SHIFT 16 26 #define SUN8I_SID_OP_LOCK (0xAC << 8) 27 #define SUN8I_SID_READ BIT(1) 28 29 struct sunxi_sid_cfg { 30 u32 value_offset; 31 u32 size; 32 bool need_register_readout; 33 }; 34 35 struct sunxi_sid { 36 void __iomem *base; 37 u32 value_offset; 38 }; 39 40 static int sunxi_sid_read(void *context, unsigned int offset, 41 void *val, size_t bytes) 42 { 43 struct sunxi_sid *sid = context; 44 45 memcpy_fromio(val, sid->base + sid->value_offset + offset, bytes); 46 47 return 0; 48 } 49 50 static int sun8i_sid_register_readout(const struct sunxi_sid *sid, 51 const unsigned int offset, 52 u32 *out) 53 { 54 u32 reg_val; 55 int ret; 56 57 /* Set word, lock access, and set read command */ 58 reg_val = (offset & SUN8I_SID_OFFSET_MASK) 59 << SUN8I_SID_OFFSET_SHIFT; 60 reg_val |= SUN8I_SID_OP_LOCK | SUN8I_SID_READ; 61 writel(reg_val, sid->base + SUN8I_SID_PRCTL); 62 63 ret = readl_poll_timeout(sid->base + SUN8I_SID_PRCTL, reg_val, 64 !(reg_val & SUN8I_SID_READ), 100, 250000); 65 if (ret) 66 return ret; 67 68 if (out) 69 *out = readl(sid->base + SUN8I_SID_RDKEY); 70 71 writel(0, sid->base + SUN8I_SID_PRCTL); 72 73 return 0; 74 } 75 76 /* 77 * On Allwinner H3, the value on the 0x200 offset of the SID controller seems 78 * to be not reliable at all. 79 * Read by the registers instead. 80 */ 81 static int sun8i_sid_read_by_reg(void *context, unsigned int offset, 82 void *val, size_t bytes) 83 { 84 struct sunxi_sid *sid = context; 85 u32 word; 86 int ret; 87 88 /* .stride = 4 so offset is guaranteed to be aligned */ 89 while (bytes >= 4) { 90 ret = sun8i_sid_register_readout(sid, offset, val); 91 if (ret) 92 return ret; 93 94 val += 4; 95 offset += 4; 96 bytes -= 4; 97 } 98 99 if (!bytes) 100 return 0; 101 102 /* Handle any trailing bytes */ 103 ret = sun8i_sid_register_readout(sid, offset, &word); 104 if (ret) 105 return ret; 106 107 memcpy(val, &word, bytes); 108 109 return 0; 110 } 111 112 static int sunxi_sid_probe(struct platform_device *pdev) 113 { 114 struct device *dev = &pdev->dev; 115 struct resource *res; 116 struct nvmem_config *nvmem_cfg; 117 struct nvmem_device *nvmem; 118 struct sunxi_sid *sid; 119 int size; 120 char *randomness; 121 const struct sunxi_sid_cfg *cfg; 122 123 sid = devm_kzalloc(dev, sizeof(*sid), GFP_KERNEL); 124 if (!sid) 125 return -ENOMEM; 126 127 cfg = of_device_get_match_data(dev); 128 if (!cfg) 129 return -EINVAL; 130 sid->value_offset = cfg->value_offset; 131 132 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 133 sid->base = devm_ioremap_resource(dev, res); 134 if (IS_ERR(sid->base)) 135 return PTR_ERR(sid->base); 136 137 size = cfg->size; 138 139 nvmem_cfg = devm_kzalloc(dev, sizeof(*nvmem_cfg), GFP_KERNEL); 140 if (!nvmem_cfg) 141 return -ENOMEM; 142 143 nvmem_cfg->dev = dev; 144 nvmem_cfg->name = "sunxi-sid"; 145 nvmem_cfg->read_only = true; 146 nvmem_cfg->size = cfg->size; 147 nvmem_cfg->word_size = 1; 148 nvmem_cfg->stride = 4; 149 nvmem_cfg->priv = sid; 150 if (cfg->need_register_readout) 151 nvmem_cfg->reg_read = sun8i_sid_read_by_reg; 152 else 153 nvmem_cfg->reg_read = sunxi_sid_read; 154 155 nvmem = devm_nvmem_register(dev, nvmem_cfg); 156 if (IS_ERR(nvmem)) 157 return PTR_ERR(nvmem); 158 159 randomness = kzalloc(size, GFP_KERNEL); 160 if (!randomness) 161 return -ENOMEM; 162 163 nvmem_cfg->reg_read(sid, 0, randomness, size); 164 add_device_randomness(randomness, size); 165 kfree(randomness); 166 167 platform_set_drvdata(pdev, nvmem); 168 169 return 0; 170 } 171 172 static const struct sunxi_sid_cfg sun4i_a10_cfg = { 173 .size = 0x10, 174 }; 175 176 static const struct sunxi_sid_cfg sun7i_a20_cfg = { 177 .size = 0x200, 178 }; 179 180 static const struct sunxi_sid_cfg sun8i_h3_cfg = { 181 .value_offset = 0x200, 182 .size = 0x100, 183 .need_register_readout = true, 184 }; 185 186 static const struct sunxi_sid_cfg sun50i_a64_cfg = { 187 .value_offset = 0x200, 188 .size = 0x100, 189 }; 190 191 static const struct sunxi_sid_cfg sun50i_h6_cfg = { 192 .value_offset = 0x200, 193 .size = 0x200, 194 }; 195 196 static const struct of_device_id sunxi_sid_of_match[] = { 197 { .compatible = "allwinner,sun4i-a10-sid", .data = &sun4i_a10_cfg }, 198 { .compatible = "allwinner,sun7i-a20-sid", .data = &sun7i_a20_cfg }, 199 { .compatible = "allwinner,sun8i-a83t-sid", .data = &sun50i_a64_cfg }, 200 { .compatible = "allwinner,sun8i-h3-sid", .data = &sun8i_h3_cfg }, 201 { .compatible = "allwinner,sun50i-a64-sid", .data = &sun50i_a64_cfg }, 202 { .compatible = "allwinner,sun50i-h5-sid", .data = &sun50i_a64_cfg }, 203 { .compatible = "allwinner,sun50i-h6-sid", .data = &sun50i_h6_cfg }, 204 {/* sentinel */}, 205 }; 206 MODULE_DEVICE_TABLE(of, sunxi_sid_of_match); 207 208 static struct platform_driver sunxi_sid_driver = { 209 .probe = sunxi_sid_probe, 210 .driver = { 211 .name = "eeprom-sunxi-sid", 212 .of_match_table = sunxi_sid_of_match, 213 }, 214 }; 215 module_platform_driver(sunxi_sid_driver); 216 217 MODULE_AUTHOR("Oliver Schinagl <oliver@schinagl.nl>"); 218 MODULE_DESCRIPTION("Allwinner sunxi security id driver"); 219 MODULE_LICENSE("GPL"); 220