[U-Boot] [PATCH 18/37] bootcount: add a DM i2c eeprom backing store for bootcount

Robert Beckett
2019-10-15T15:53:31Z

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>
---
drivers/bootcount/Kconfig | 10 ++++
drivers/bootcount/Makefile | 1 +
drivers/bootcount/i2c-eeprom.c | 95 ++++++++++++++++++++++++++++++++++
3 files changed, 106 insertions(+)
create mode 100644 drivers/bootcount/i2c-eeprom.c

diff --git a/drivers/bootcount/Kconfig b/drivers/bootcount/Kconfig
index b7c29f2fd3..0e506c9ea2 100644
--- 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 f9841d8615..73ccfb5a08 100644
--- 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
index 0000000000..ee760a2742
--- /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,
+};
--
2.20.1