drivers/nvmem/imx-ocotp-scu.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * i.MX8 OCOTP fusebox driver
   4  *
   5  * Copyright 2019 NXP
   6  *
   7  * Peng Fan <peng.fan@nxp.com>
   8  */
   9
  10 #include <linux/arm-smccc.h>
  11 #include <linux/firmware/imx/sci.h>
  12 #include <linux/module.h>
  13 #include <linux/nvmem-provider.h>
  14 #include <linux/of.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/slab.h>
  17
  18 #define IMX_SIP_OTP_WRITE               0xc200000B
  19
  20 enum ocotp_devtype {
  21         IMX8QXP,
  22         IMX8QM,
  23 };
  24
  25 #define ECC_REGION      BIT(0)
  26 #define HOLE_REGION     BIT(1)
  27
  28 struct ocotp_region {
  29         u32 start;
  30         u32 end;
  31         u32 flag;
  32 };
  33
  34 struct ocotp_devtype_data {
  35         int devtype;
  36         int nregs;
  37         u32 num_region;
  38         struct ocotp_region region[];
  39 };
  40
  41 struct ocotp_priv {
  42         struct device *dev;
  43         const struct ocotp_devtype_data *data;
  44         struct imx_sc_ipc *nvmem_ipc;
  45 };
  46
  47 struct imx_sc_msg_misc_fuse_read {
  48         struct imx_sc_rpc_msg hdr;
  49         u32 word;
  50 } __packed;
  51
  52 static DEFINE_MUTEX(scu_ocotp_mutex);
  53
  54 static struct ocotp_devtype_data imx8qxp_data = {
  55         .devtype = IMX8QXP,
  56         .nregs = 800,
  57         .num_region = 3,
  58         .region = {
  59                 {0x10, 0x10f, ECC_REGION},
  60                 {0x110, 0x21F, HOLE_REGION},
  61                 {0x220, 0x31F, ECC_REGION},
  62         },
  63 };
  64
  65 static struct ocotp_devtype_data imx8qm_data = {
  66         .devtype = IMX8QM,
  67         .nregs = 800,
  68         .num_region = 2,
  69         .region = {
  70                 {0x10, 0x10f, ECC_REGION},
  71                 {0x1a0, 0x1ff, ECC_REGION},
  72         },
  73 };
  74
  75 static bool in_hole(void *context, u32 index)
  76 {
  77         struct ocotp_priv *priv = context;
  78         const struct ocotp_devtype_data *data = priv->data;
  79         int i;
  80
  81         for (i = 0; i < data->num_region; i++) {
  82                 if (data->region[i].flag & HOLE_REGION) {
  83                         if ((index >= data->region[i].start) &&
  84                             (index <= data->region[i].end))
  85                                 return true;
  86                 }
  87         }
  88
  89         return false;
  90 }
  91
  92 static bool in_ecc(void *context, u32 index)
  93 {
  94         struct ocotp_priv *priv = context;
  95         const struct ocotp_devtype_data *data = priv->data;
  96         int i;
  97
  98         for (i = 0; i < data->num_region; i++) {
  99                 if (data->region[i].flag & ECC_REGION) {
 100                         if ((index >= data->region[i].start) &&
 101                             (index <= data->region[i].end))
 102                                 return true;
 103                 }
 104         }
 105
 106         return false;
 107 }
 108
 109 static int imx_sc_misc_otp_fuse_read(struct imx_sc_ipc *ipc, u32 word,
 110                                      u32 *val)
 111 {
 112         struct imx_sc_msg_misc_fuse_read msg;
 113         struct imx_sc_rpc_msg *hdr = &msg.hdr;
 114         int ret;
 115
 116         hdr->ver = IMX_SC_RPC_VERSION;
 117         hdr->svc = IMX_SC_RPC_SVC_MISC;
 118         hdr->func = IMX_SC_MISC_FUNC_OTP_FUSE_READ;
 119         hdr->size = 2;
 120
 121         msg.word = word;
 122
 123         ret = imx_scu_call_rpc(ipc, &msg, true);
 124         if (ret)
 125                 return ret;
 126
 127         *val = msg.word;
 128
 129         return 0;
 130 }
 131
 132 static int imx_scu_ocotp_read(void *context, unsigned int offset,
 133                               void *val, size_t bytes)
 134 {
 135         struct ocotp_priv *priv = context;
 136         u32 count, index, num_bytes;
 137         u32 *buf;
 138         void *p;
 139         int i, ret;
 140
 141         index = offset;
 142         num_bytes = round_up(bytes, 4);
 143         count = num_bytes >> 2;
 144
 145         if (count > (priv->data->nregs - index))
 146                 count = priv->data->nregs - index;
 147
 148         p = kzalloc(num_bytes, GFP_KERNEL);
 149         if (!p)
 150                 return -ENOMEM;
 151
 152         mutex_lock(&scu_ocotp_mutex);
 153
 154         buf = p;
 155
 156         for (i = index; i < (index + count); i++) {
 157                 if (in_hole(context, i)) {
 158                         *buf++ = 0;
 159                         continue;
 160                 }
 161
 162                 ret = imx_sc_misc_otp_fuse_read(priv->nvmem_ipc, i, buf);
 163                 if (ret) {
 164                         mutex_unlock(&scu_ocotp_mutex);
 165                         kfree(p);
 166                         return ret;
 167                 }
 168                 buf++;
 169         }
 170
 171         memcpy(val, (u8 *)p, bytes);
 172
 173         mutex_unlock(&scu_ocotp_mutex);
 174
 175         kfree(p);
 176
 177         return 0;
 178 }
 179
 180 static int imx_scu_ocotp_write(void *context, unsigned int offset,
 181                                void *val, size_t bytes)
 182 {
 183         struct ocotp_priv *priv = context;
 184         struct arm_smccc_res res;
 185         u32 *buf = val;
 186         u32 tmp;
 187         u32 index;
 188         int ret;
 189
 190         /* allow only writing one complete OTP word at a time */
 191         if (bytes != 4)
 192                 return -EINVAL;
 193
 194         index = offset;
 195
 196         if (in_hole(context, index))
 197                 return -EINVAL;
 198
 199         if (in_ecc(context, index)) {
 200                 pr_warn("ECC region, only program once\n");
 201                 mutex_lock(&scu_ocotp_mutex);
 202                 ret = imx_sc_misc_otp_fuse_read(priv->nvmem_ipc, index, &tmp);
 203                 mutex_unlock(&scu_ocotp_mutex);
 204                 if (ret)
 205                         return ret;
 206                 if (tmp) {
 207                         pr_warn("ECC region, already has value: %x\n", tmp);
 208                         return -EIO;
 209                 }
 210         }
 211
 212         mutex_lock(&scu_ocotp_mutex);
 213
 214         arm_smccc_smc(IMX_SIP_OTP_WRITE, index, *buf, 0, 0, 0, 0, 0, &res);
 215
 216         mutex_unlock(&scu_ocotp_mutex);
 217
 218         return res.a0;
 219 }
 220
 221 static struct nvmem_config imx_scu_ocotp_nvmem_config = {
 222         .name = "imx-scu-ocotp",
 223         .read_only = false,
 224         .word_size = 4,
 225         .stride = 1,
 226         .owner = THIS_MODULE,
 227         .reg_read = imx_scu_ocotp_read,
 228         .reg_write = imx_scu_ocotp_write,
 229 };
 230
 231 static const struct of_device_id imx_scu_ocotp_dt_ids[] = {
 232         { .compatible = "fsl,imx8qxp-scu-ocotp", (void *)&imx8qxp_data },
 233         { .compatible = "fsl,imx8qm-scu-ocotp", (void *)&imx8qm_data },
 234         { },
 235 };
 236 MODULE_DEVICE_TABLE(of, imx_scu_ocotp_dt_ids);
 237
 238 static int imx_scu_ocotp_probe(struct platform_device *pdev)
 239 {
 240         struct device *dev = &pdev->dev;
 241         struct ocotp_priv *priv;
 242         struct nvmem_device *nvmem;
 243         int ret;
 244
 245         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 246         if (!priv)
 247                 return -ENOMEM;
 248
 249         ret = imx_scu_get_handle(&priv->nvmem_ipc);
 250         if (ret)
 251                 return ret;
 252
 253         priv->data = of_device_get_match_data(dev);
 254         priv->dev = dev;
 255         imx_scu_ocotp_nvmem_config.size = 4 * priv->data->nregs;
 256         imx_scu_ocotp_nvmem_config.dev = dev;
 257         imx_scu_ocotp_nvmem_config.priv = priv;
 258         nvmem = devm_nvmem_register(dev, &imx_scu_ocotp_nvmem_config);
 259
 260         return PTR_ERR_OR_ZERO(nvmem);
 261 }
 262
 263 static struct platform_driver imx_scu_ocotp_driver = {
 264         .probe  = imx_scu_ocotp_probe,
 265         .driver = {
 266                 .name   = "imx_scu_ocotp",
 267                 .of_match_table = imx_scu_ocotp_dt_ids,
 268         },
 269 };
 270 module_platform_driver(imx_scu_ocotp_driver);
 271
 272 MODULE_AUTHOR("Peng Fan <peng.fan@nxp.com>");
 273 MODULE_DESCRIPTION("i.MX8 SCU OCOTP fuse box driver");
 274 MODULE_LICENSE("GPL v2");