target/linux/generic/backport-5.10/801-v5.11-0003-nvmem-imx-ocotp-add-support-for-the-unaliged-word-co.patch

   1 From 3311bf18467272388039922a5e29c4925b291f73 Mon Sep 17 00:00:00 2001
   2 From: Peng Fan <peng.fan@nxp.com>
   3 Date: Fri, 27 Nov 2020 10:28:37 +0000
   4 Subject: [PATCH] nvmem: imx-ocotp: add support for the unaliged word count
   5
   6 When offset is not 4 bytes aligned, directly shift righty by 2 bits
   7 will cause reading out wrong data. Since imx ocotp only supports
   8 4 bytes reading once, we need handle offset is not 4 bytes aligned
   9 and enlarge the bytes to 4 bytes aligned. After reading finished,
  10 copy the needed data from buffer to caller and free buffer.
  11
  12 Signed-off-by: Peng Fan <peng.fan@nxp.com>
  13 Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
  14 Link: https://lore.kernel.org/r/20201127102837.19366-6-srinivas.kandagatla@linaro.org
  15 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  16 ---
  17  drivers/nvmem/imx-ocotp.c | 30 ++++++++++++++++++++++++------
  18  1 file changed, 24 insertions(+), 6 deletions(-)
  19
  20 --- a/drivers/nvmem/imx-ocotp.c
  21 +++ b/drivers/nvmem/imx-ocotp.c
  22 @@ -4,6 +4,8 @@
  23   *
  24   * Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de>
  25   *
  26 + * Copyright 2019 NXP
  27 + *
  28   * Based on the barebox ocotp driver,
  29   * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>,
  30   *     Orex Computed Radiography
  31 @@ -158,22 +160,30 @@ static int imx_ocotp_read(void *context,
  32  {
  33         struct ocotp_priv *priv = context;
  34         unsigned int count;
  35 -       u32 *buf = val;
  36 +       u8 *buf, *p;
  37         int i, ret;
  38 -       u32 index;
  39 +       u32 index, num_bytes;
  40
  41         index = offset >> 2;
  42 -       count = bytes >> 2;
  43 +       num_bytes = round_up((offset % 4) + bytes, 4);
  44 +       count = num_bytes >> 2;
  45
  46         if (count > (priv->params->nregs - index))
  47                 count = priv->params->nregs - index;
  48
  49 +       p = kzalloc(num_bytes, GFP_KERNEL);
  50 +       if (!p)
  51 +               return -ENOMEM;
  52 +
  53         mutex_lock(&ocotp_mutex);
  54
  55 +       buf = p;
  56 +
  57         ret = clk_prepare_enable(priv->clk);
  58         if (ret < 0) {
  59                 mutex_unlock(&ocotp_mutex);
  60                 dev_err(priv->dev, "failed to prepare/enable ocotp clk\n");
  61 +               kfree(p);
  62                 return ret;
  63         }
  64
  65 @@ -184,7 +194,7 @@ static int imx_ocotp_read(void *context,
  66         }
  67
  68         for (i = index; i < (index + count); i++) {
  69 -               *buf++ = readl(priv->base + IMX_OCOTP_OFFSET_B0W0 +
  70 +               *(u32 *)buf = readl(priv->base + IMX_OCOTP_OFFSET_B0W0 +
  71                                i * IMX_OCOTP_OFFSET_PER_WORD);
  72
  73                 /* 47.3.1.2
  74 @@ -193,13 +203,21 @@ static int imx_ocotp_read(void *context,
  75                  * software before any new write, read or reload access can be
  76                  * issued
  77                  */
  78 -               if (*(buf - 1) == IMX_OCOTP_READ_LOCKED_VAL)
  79 +               if (*((u32 *)buf) == IMX_OCOTP_READ_LOCKED_VAL)
  80                         imx_ocotp_clr_err_if_set(priv);
  81 +
  82 +               buf += 4;
  83         }
  84
  85 +       index = offset % 4;
  86 +       memcpy(val, &p[index], bytes);
  87 +
  88  read_end:
  89         clk_disable_unprepare(priv->clk);
  90         mutex_unlock(&ocotp_mutex);
  91 +
  92 +       kfree(p);
  93 +
  94         return ret;
  95  }
  96
  97 @@ -447,7 +465,7 @@ static struct nvmem_config imx_ocotp_nvm
  98         .name = "imx-ocotp",
  99         .read_only = false,
 100         .word_size = 4,
 101 -       .stride = 4,
 102 +       .stride = 1,
 103         .reg_read = imx_ocotp_read,
 104         .reg_write = imx_ocotp_write,
 105  };