drivers/bootcount/i2c-eeprom.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * (C) Copyright 2019 Collabora
   4  * (C) Copyright 2019 GE
   5  */
   6
   7 #include <common.h>
   8 #include <bootcount.h>
   9 #include <dm.h>
  10 #include <i2c_eeprom.h>
  11
  12 static const u8 bootcount_magic = 0xbc;
  13
  14 struct bootcount_i2c_eeprom_priv {
  15         struct udevice *i2c_eeprom;
  16         u32 offset;
  17 };
  18
  19 static int bootcount_i2c_eeprom_set(struct udevice *dev, const u32 a)
  20 {
  21         struct bootcount_i2c_eeprom_priv *priv = dev_get_priv(dev);
  22         const u16 val = bootcount_magic << 8 | (a & 0xff);
  23
  24         if (i2c_eeprom_write(priv->i2c_eeprom, priv->offset,
  25                              (uint8_t *)&val, 2) < 0) {
  26                 debug("%s: write failed\n", __func__);
  27                 return -EIO;
  28         }
  29
  30         return 0;
  31 }
  32
  33 static int bootcount_i2c_eeprom_get(struct udevice *dev, u32 *a)
  34 {
  35         struct bootcount_i2c_eeprom_priv *priv = dev_get_priv(dev);
  36         u16 val;
  37
  38         if (i2c_eeprom_read(priv->i2c_eeprom, priv->offset,
  39                             (uint8_t *)&val, 2) < 0) {
  40                 debug("%s: read failed\n", __func__);
  41                 return -EIO;
  42         }
  43
  44         if (val >> 8 == bootcount_magic) {
  45                 *a = val & 0xff;
  46                 return 0;
  47         }
  48
  49         debug("%s: bootcount magic does not match on %04x\n", __func__, val);
  50         return -EIO;
  51 }
  52
  53 static int bootcount_i2c_eeprom_probe(struct udevice *dev)
  54 {
  55         struct ofnode_phandle_args phandle_args;
  56         struct bootcount_i2c_eeprom_priv *priv = dev_get_priv(dev);
  57         struct udevice *i2c_eeprom;
  58
  59         if (dev_read_phandle_with_args(dev, "i2c-eeprom", NULL, 0, 0,
  60                                        &phandle_args)) {
  61                 debug("%s: i2c-eeprom backing device not specified\n",
  62                       dev->name);
  63                 return -ENOENT;
  64         }
  65
  66         if (uclass_get_device_by_ofnode(UCLASS_I2C_EEPROM, phandle_args.node,
  67                                         &i2c_eeprom)) {
  68                 debug("%s: could not get backing device\n", dev->name);
  69                 return -ENODEV;
  70         }
  71
  72         priv->i2c_eeprom = i2c_eeprom;
  73         priv->offset = dev_read_u32_default(dev, "offset", 0);
  74
  75         return 0;
  76 }
  77
  78 static const struct bootcount_ops bootcount_i2c_eeprom_ops = {
  79         .get = bootcount_i2c_eeprom_get,
  80         .set = bootcount_i2c_eeprom_set,
  81 };
  82
  83 static const struct udevice_id bootcount_i2c_eeprom_ids[] = {
  84         { .compatible = "u-boot,bootcount-i2c-eeprom" },
  85         { }
  86 };
  87
  88 U_BOOT_DRIVER(bootcount_spi_flash) = {
  89         .name   = "bootcount-i2c-eeprom",
  90         .id     = UCLASS_BOOTCOUNT,
  91         .priv_auto_alloc_size = sizeof(struct bootcount_i2c_eeprom_priv),
  92         .probe  = bootcount_i2c_eeprom_probe,
  93         .of_match = bootcount_i2c_eeprom_ids,
  94         .ops    = &bootcount_i2c_eeprom_ops,
  95 };