bootcount: add a DM i2c eeprom backing store for bootcount

This driver allows the use of i2c eeprom device or partition as backing
store for boot counter values with DM enabled.

Signed-off-by: Robert Beckett <bob.beckett@collabora.com>

diff --git a/drivers/bootcount/Kconfig b/drivers/bootcount/Kconfig
index b7c29f2fd30de36103f218ae65b3559a32b49f70..0e506c9ea2a8021f07b03af72ed64eea31332b58 100644 (file)
--- a/drivers/bootcount/Kconfig
+++ b/drivers/bootcount/Kconfig
@@ -96,6 +96,16 @@ config DM_BOOTCOUNT_RTC
          Accesses to the backing store are performed using the write16
          and read16 ops of DM RTC devices.
 
+config DM_BOOTCOUNT_I2C_EEPROM
+       bool "Support i2c eeprom devices as a backing store for bootcount"
+       depends on I2C_EEPROM
+       help
+         Enabled reading/writing the bootcount in a DM i2c eeprom device.
+         The wrapper device is to be specified with the compatible string
+         'u-boot,bootcount-i2c-eeprom' and the 'i2c-eeprom'-property (a phandle
+         pointing to the underlying i2c eeprom device) and an optional 'offset'
+         property are supported.
+
 endmenu
 
 endif

diff --git a/drivers/bootcount/Makefile b/drivers/bootcount/Makefile
index f9841d86156fbdbc60bb32bf6f90ae434aa61460..73ccfb5a08889b54c31494810568bf3f310e9a06 100644 (file)
--- a/drivers/bootcount/Makefile
+++ b/drivers/bootcount/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_BOOTCOUNT_EXT)   += bootcount_ext.o
 
 obj-$(CONFIG_DM_BOOTCOUNT)      += bootcount-uclass.o
 obj-$(CONFIG_DM_BOOTCOUNT_RTC)  += rtc.o
+obj-$(CONFIG_DM_BOOTCOUNT_I2C_EEPROM)  += i2c-eeprom.o

diff --git a/drivers/bootcount/i2c-eeprom.c b/drivers/bootcount/i2c-eeprom.c
new file mode 100644 (file)
index 0000000..ee760a2
--- /dev/null
+++ b/drivers/bootcount/i2c-eeprom.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2019 Collabora
+ * (C) Copyright 2019 GE
+ */
+
+#include <common.h>
+#include <bootcount.h>
+#include <dm.h>
+#include <i2c_eeprom.h>
+
+static const u8 bootcount_magic = 0xbc;
+
+struct bootcount_i2c_eeprom_priv {
+       struct udevice *i2c_eeprom;
+       u32 offset;
+};
+
+static int bootcount_i2c_eeprom_set(struct udevice *dev, const u32 a)
+{
+       struct bootcount_i2c_eeprom_priv *priv = dev_get_priv(dev);
+       const u16 val = bootcount_magic << 8 | (a & 0xff);
+
+       if (i2c_eeprom_write(priv->i2c_eeprom, priv->offset,
+                            (uint8_t *)&val, 2) < 0) {
+               debug("%s: write failed\n", __func__);
+               return -EIO;
+       }
+
+       return 0;
+}
+
+static int bootcount_i2c_eeprom_get(struct udevice *dev, u32 *a)
+{
+       struct bootcount_i2c_eeprom_priv *priv = dev_get_priv(dev);
+       u16 val;
+
+       if (i2c_eeprom_read(priv->i2c_eeprom, priv->offset,
+                           (uint8_t *)&val, 2) < 0) {
+               debug("%s: read failed\n", __func__);
+               return -EIO;
+       }
+
+       if (val >> 8 == bootcount_magic) {
+               *a = val & 0xff;
+               return 0;
+       }
+
+       debug("%s: bootcount magic does not match on %04x\n", __func__, val);
+       return -EIO;
+}
+
+static int bootcount_i2c_eeprom_probe(struct udevice *dev)
+{
+       struct ofnode_phandle_args phandle_args;
+       struct bootcount_i2c_eeprom_priv *priv = dev_get_priv(dev);
+       struct udevice *i2c_eeprom;
+
+       if (dev_read_phandle_with_args(dev, "i2c-eeprom", NULL, 0, 0,
+                                      &phandle_args)) {
+               debug("%s: i2c-eeprom backing device not specified\n",
+                     dev->name);
+               return -ENOENT;
+       }
+
+       if (uclass_get_device_by_ofnode(UCLASS_I2C_EEPROM, phandle_args.node,
+                                       &i2c_eeprom)) {
+               debug("%s: could not get backing device\n", dev->name);
+               return -ENODEV;
+       }
+
+       priv->i2c_eeprom = i2c_eeprom;
+       priv->offset = dev_read_u32_default(dev, "offset", 0);
+
+       return 0;
+}
+
+static const struct bootcount_ops bootcount_i2c_eeprom_ops = {
+       .get = bootcount_i2c_eeprom_get,
+       .set = bootcount_i2c_eeprom_set,
+};
+
+static const struct udevice_id bootcount_i2c_eeprom_ids[] = {
+       { .compatible = "u-boot,bootcount-i2c-eeprom" },
+       { }
+};
+
+U_BOOT_DRIVER(bootcount_spi_flash) = {
+       .name   = "bootcount-i2c-eeprom",
+       .id     = UCLASS_BOOTCOUNT,
+       .priv_auto_alloc_size = sizeof(struct bootcount_i2c_eeprom_priv),
+       .probe  = bootcount_i2c_eeprom_probe,
+       .of_match = bootcount_i2c_eeprom_ids,
+       .ops    = &bootcount_i2c_eeprom_ops,
+};