drivers/bootcount/spi-flash.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 <spi_flash.h>
  11
  12 static const u8 bootcount_magic = 0xbc;
  13
  14 struct bootcount_spi_flash_priv {
  15         struct udevice *spi_flash;
  16         u32 offset;
  17 };
  18
  19 static int bootcount_spi_flash_update(struct udevice *dev, u32 offset, u32 len, const void *buf)
  20 {
  21         struct spi_flash *flash = dev_get_uclass_priv(dev);
  22         u32 sector_size = flash->sector_size;
  23         u32 sector_offset = offset % sector_size;
  24         u32 sector = offset - sector_offset;
  25         int err = 0;
  26
  27         /* code only supports updating a single sector */
  28         if (sector_offset + len > sector_size)
  29                 return -ENOSYS;
  30
  31         u8 *buffer = malloc(sector_size);
  32         if (!buffer)
  33                 return -ENOMEM;
  34
  35         err = spi_flash_read_dm(dev, sector, sector_size, buffer);
  36         if (err < 0)
  37                 goto out;
  38
  39         memcpy(buffer + sector_offset, buf, len);
  40
  41         err = spi_flash_erase_dm(dev, sector, sector_size);
  42         if (err < 0)
  43                 goto out;
  44
  45         err = spi_flash_write_dm(dev, sector, sector_size, buffer);
  46         if (err < 0)
  47                 goto out;
  48
  49 out:
  50         free(buffer);
  51         return err;
  52 }
  53
  54 static int bootcount_spi_flash_set(struct udevice *dev, const u32 a)
  55 {
  56         struct bootcount_spi_flash_priv *priv = dev_get_priv(dev);
  57         const u16 val = bootcount_magic << 8 | (a & 0xff);
  58
  59         if (bootcount_spi_flash_update(priv->spi_flash, priv->offset, 2, &val) < 0) {
  60                 debug("%s: write failed\n", __func__);
  61                 return -EIO;
  62         }
  63
  64         return 0;
  65 }
  66
  67 static int bootcount_spi_flash_get(struct udevice *dev, u32 *a)
  68 {
  69         struct bootcount_spi_flash_priv *priv = dev_get_priv(dev);
  70         u16 val;
  71
  72         if (spi_flash_read_dm(priv->spi_flash, priv->offset, 2, &val) < 0) {
  73                 debug("%s: read failed\n", __func__);
  74                 return -EIO;
  75         }
  76
  77         if (val >> 8 == bootcount_magic) {
  78                 *a = val & 0xff;
  79                 return 0;
  80         }
  81
  82         debug("%s: bootcount magic does not match on %04x\n", __func__, val);
  83         return -EIO;
  84 }
  85
  86 static int bootcount_spi_flash_probe(struct udevice *dev)
  87 {
  88         struct ofnode_phandle_args phandle_args;
  89         struct bootcount_spi_flash_priv *priv = dev_get_priv(dev);
  90         struct udevice *spi_flash;
  91
  92         if (dev_read_phandle_with_args(dev, "spi-flash", NULL, 0, 0, &phandle_args)) {
  93                 debug("%s: spi-flash backing device not specified\n", dev->name);
  94                 return -ENOENT;
  95         }
  96
  97         if (uclass_get_device_by_ofnode(UCLASS_SPI_FLASH, phandle_args.node, &spi_flash)) {
  98                 debug("%s: could not get backing device\n", dev->name);
  99                 return -ENODEV;
 100         }
 101
 102         priv->spi_flash = spi_flash;
 103         priv->offset = dev_read_u32_default(dev, "offset", 0);
 104
 105         return 0;
 106 }
 107
 108 static const struct bootcount_ops bootcount_spi_flash_ops = {
 109         .get = bootcount_spi_flash_get,
 110         .set = bootcount_spi_flash_set,
 111 };
 112
 113 static const struct udevice_id bootcount_spi_flash_ids[] = {
 114         { .compatible = "u-boot,bootcount-spi-flash" },
 115         { }
 116 };
 117
 118 U_BOOT_DRIVER(bootcount_spi_flash) = {
 119         .name   = "bootcount-spi-flash",
 120         .id     = UCLASS_BOOTCOUNT,
 121         .priv_auto      = sizeof(struct bootcount_spi_flash_priv),
 122         .probe  = bootcount_spi_flash_probe,
 123         .of_match = bootcount_spi_flash_ids,
 124         .ops    = &bootcount_spi_flash_ops,
 125 };