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/firmware/imx/sci.h>
  11 #include <linux/module.h>
  12 #include <linux/nvmem-provider.h>
  13 #include <linux/of_device.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/slab.h>
  16
  17 enum ocotp_devtype {
  18         IMX8QXP,
  19 };
  20
  21 struct ocotp_devtype_data {
  22         int devtype;
  23         int nregs;
  24 };
  25
  26 struct ocotp_priv {
  27         struct device *dev;
  28         const struct ocotp_devtype_data *data;
  29         struct imx_sc_ipc *nvmem_ipc;
  30 };
  31
  32 struct imx_sc_msg_misc_fuse_read {
  33         struct imx_sc_rpc_msg hdr;
  34         u32 word;
  35 } __packed;
  36
  37 static struct ocotp_devtype_data imx8qxp_data = {
  38         .devtype = IMX8QXP,
  39         .nregs = 800,
  40 };
  41
  42 static int imx_sc_misc_otp_fuse_read(struct imx_sc_ipc *ipc, u32 word,
  43                                      u32 *val)
  44 {
  45         struct imx_sc_msg_misc_fuse_read msg;
  46         struct imx_sc_rpc_msg *hdr = &msg.hdr;
  47         int ret;
  48
  49         hdr->ver = IMX_SC_RPC_VERSION;
  50         hdr->svc = IMX_SC_RPC_SVC_MISC;
  51         hdr->func = IMX_SC_MISC_FUNC_OTP_FUSE_READ;
  52         hdr->size = 2;
  53
  54         msg.word = word;
  55
  56         ret = imx_scu_call_rpc(ipc, &msg, true);
  57         if (ret)
  58                 return ret;
  59
  60         *val = msg.word;
  61
  62         return 0;
  63 }
  64
  65 static int imx_scu_ocotp_read(void *context, unsigned int offset,
  66                               void *val, size_t bytes)
  67 {
  68         struct ocotp_priv *priv = context;
  69         u32 count, index, num_bytes;
  70         u32 *buf;
  71         void *p;
  72         int i, ret;
  73
  74         index = offset >> 2;
  75         num_bytes = round_up((offset % 4) + bytes, 4);
  76         count = num_bytes >> 2;
  77
  78         if (count > (priv->data->nregs - index))
  79                 count = priv->data->nregs - index;
  80
  81         p = kzalloc(num_bytes, GFP_KERNEL);
  82         if (!p)
  83                 return -ENOMEM;
  84
  85         buf = p;
  86
  87         for (i = index; i < (index + count); i++) {
  88                 if (priv->data->devtype == IMX8QXP) {
  89                         if ((i > 271) && (i < 544)) {
  90                                 *buf++ = 0;
  91                                 continue;
  92                         }
  93                 }
  94
  95                 ret = imx_sc_misc_otp_fuse_read(priv->nvmem_ipc, i, buf);
  96                 if (ret) {
  97                         kfree(p);
  98                         return ret;
  99                 }
 100                 buf++;
 101         }
 102
 103         memcpy(val, (u8 *)p + offset % 4, bytes);
 104
 105         kfree(p);
 106
 107         return 0;
 108 }
 109
 110 static struct nvmem_config imx_scu_ocotp_nvmem_config = {
 111         .name = "imx-scu-ocotp",
 112         .read_only = true,
 113         .word_size = 4,
 114         .stride = 1,
 115         .owner = THIS_MODULE,
 116         .reg_read = imx_scu_ocotp_read,
 117 };
 118
 119 static const struct of_device_id imx_scu_ocotp_dt_ids[] = {
 120         { .compatible = "fsl,imx8qxp-scu-ocotp", (void *)&imx8qxp_data },
 121         { },
 122 };
 123 MODULE_DEVICE_TABLE(of, imx_scu_ocotp_dt_ids);
 124
 125 static int imx_scu_ocotp_probe(struct platform_device *pdev)
 126 {
 127         struct device *dev = &pdev->dev;
 128         struct ocotp_priv *priv;
 129         struct nvmem_device *nvmem;
 130         int ret;
 131
 132         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 133         if (!priv)
 134                 return -ENOMEM;
 135
 136         ret = imx_scu_get_handle(&priv->nvmem_ipc);
 137         if (ret)
 138                 return ret;
 139
 140         priv->data = of_device_get_match_data(dev);
 141         priv->dev = dev;
 142         imx_scu_ocotp_nvmem_config.size = 4 * priv->data->nregs;
 143         imx_scu_ocotp_nvmem_config.dev = dev;
 144         imx_scu_ocotp_nvmem_config.priv = priv;
 145         nvmem = devm_nvmem_register(dev, &imx_scu_ocotp_nvmem_config);
 146
 147         return PTR_ERR_OR_ZERO(nvmem);
 148 }
 149
 150 static struct platform_driver imx_scu_ocotp_driver = {
 151         .probe  = imx_scu_ocotp_probe,
 152         .driver = {
 153                 .name   = "imx_scu_ocotp",
 154                 .of_match_table = imx_scu_ocotp_dt_ids,
 155         },
 156 };
 157 module_platform_driver(imx_scu_ocotp_driver);
 158
 159 MODULE_AUTHOR("Peng Fan <peng.fan@nxp.com>");
 160 MODULE_DESCRIPTION("i.MX8 SCU OCOTP fuse box driver");
 161 MODULE_LICENSE("GPL v2");