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 <bootcount.h>
   8 #include <dm.h>
   9 #include <spi_flash.h>
  10
  11 static const u8 bootcount_magic = 0xbc;
  12
  13 struct bootcount_spi_flash_priv {
  14         struct udevice *spi_flash;
  15         u32 offset;
  16 };
  17
  18 static int bootcount_spi_flash_update(struct udevice *dev, u32 offset, u32 len, const void *buf)
  19 {
  20         struct spi_flash *flash = dev_get_uclass_priv(dev);
  21         u32 sector_size = flash->sector_size;
  22         u32 sector_offset = offset % sector_size;
  23         u32 sector = offset - sector_offset;
  24         int err = 0;
  25
  26         /* code only supports updating a single sector */
  27         if (sector_offset + len > sector_size)
  28                 return -ENOSYS;
  29
  30         u8 *buffer = malloc(sector_size);
  31         if (!buffer)
  32                 return -ENOMEM;
  33
  34         err = spi_flash_read_dm(dev, sector, sector_size, buffer);
  35         if (err < 0)
  36                 goto out;
  37
  38         memcpy(buffer + sector_offset, buf, len);
  39
  40         err = spi_flash_erase_dm(dev, sector, sector_size);
  41         if (err < 0)
  42                 goto out;
  43
  44         err = spi_flash_write_dm(dev, sector, sector_size, buffer);
  45         if (err < 0)
  46                 goto out;
  47
  48 out:
  49         free(buffer);
  50         return err;
  51 }
  52
  53 static int bootcount_spi_flash_set(struct udevice *dev, const u32 a)
  54 {
  55         struct bootcount_spi_flash_priv *priv = dev_get_priv(dev);
  56         const u16 val = bootcount_magic << 8 | (a & 0xff);
  57
  58         if (bootcount_spi_flash_update(priv->spi_flash, priv->offset, 2, &val) < 0) {
  59                 debug("%s: write failed\n", __func__);
  60                 return -EIO;
  61         }
  62
  63         return 0;
  64 }
  65
  66 static int bootcount_spi_flash_get(struct udevice *dev, u32 *a)
  67 {
  68         struct bootcount_spi_flash_priv *priv = dev_get_priv(dev);
  69         u16 val;
  70
  71         if (spi_flash_read_dm(priv->spi_flash, priv->offset, 2, &val) < 0) {
  72                 debug("%s: read failed\n", __func__);
  73                 return -EIO;
  74         }
  75
  76         if (val >> 8 == bootcount_magic) {
  77                 *a = val & 0xff;
  78                 return 0;
  79         }
  80
  81         debug("%s: bootcount magic does not match on %04x\n", __func__, val);
  82         return -EIO;
  83 }
  84
  85 static int bootcount_spi_flash_probe(struct udevice *dev)
  86 {
  87         struct ofnode_phandle_args phandle_args;
  88         struct bootcount_spi_flash_priv *priv = dev_get_priv(dev);
  89         struct udevice *spi_flash;
  90
  91         if (dev_read_phandle_with_args(dev, "spi-flash", NULL, 0, 0, &phandle_args)) {
  92                 debug("%s: spi-flash backing device not specified\n", dev->name);
  93                 return -ENOENT;
  94         }
  95
  96         if (uclass_get_device_by_ofnode(UCLASS_SPI_FLASH, phandle_args.node, &spi_flash)) {
  97                 debug("%s: could not get backing device\n", dev->name);
  98                 return -ENODEV;
  99         }
 100
 101         priv->spi_flash = spi_flash;
 102         priv->offset = dev_read_u32_default(dev, "offset", 0);
 103
 104         return 0;
 105 }
 106
 107 static const struct bootcount_ops bootcount_spi_flash_ops = {
 108         .get = bootcount_spi_flash_get,
 109         .set = bootcount_spi_flash_set,
 110 };
 111
 112 static const struct udevice_id bootcount_spi_flash_ids[] = {
 113         { .compatible = "u-boot,bootcount-spi-flash" },
 114         { }
 115 };
 116
 117 U_BOOT_DRIVER(bootcount_spi_flash) = {
 118         .name   = "bootcount-spi-flash",
 119         .id     = UCLASS_BOOTCOUNT,
 120         .priv_auto      = sizeof(struct bootcount_spi_flash_priv),
 121         .probe  = bootcount_spi_flash_probe,
 122         .of_match = bootcount_spi_flash_ids,
 123         .ops    = &bootcount_spi_flash_ops,
 124 };