The original bootcount methods do not provide an interface to DM and
rely on a static configuration for I2C devices (e.g. bus, chip-addr,
etc. are configured through defines statically). On a modern system
that exposes multiple devices in a DTS-configurable way, this is less
than optimal and a interface to DM-based devices will be desirable.
This adds a simple driver that is DM-aware and configurable via DTS:
the /chosen/u-boot,bootcount-device property is used to detect the DM
device storing the bootcount and deviceclass-specific commands are
used to read/write the bootcount.
Initially, this provides support for the following DM devices:
* RTC devices implementing the read8/write8 ops
Signed-off-by: Philipp Tomsich <philipp.toms...@theobroma-systems.com>
Tested-by: Klaus Goger <klaus.go...@theobroma-systems.com>
---
doc/device-tree-bindings/chosen.txt | 27 +++++++++++
drivers/bootcount/Kconfig | 12 +++++
drivers/bootcount/Makefile | 1 +
drivers/bootcount/bootcount_dm.c | 93 +++++++++++++++++++++++++++++++++++++
4 files changed, 133 insertions(+)
create mode 100644 drivers/bootcount/bootcount_dm.c
diff --git a/doc/device-tree-bindings/chosen.txt
b/doc/device-tree-bindings/chosen.txt
index da7b4e6..734fd15 100644
--- a/doc/device-tree-bindings/chosen.txt
+++ b/doc/device-tree-bindings/chosen.txt
@@ -42,6 +42,33 @@ Example
};
};
+u-boot,bootcount-device property
+--------------------------------
+In a DM-based system, the bootcount may be stored in a device known to
+the DM framework (e.g. in a battery-backed SRAM area within a RTC
+device). To identify the device to be used for the bootcount, the
+u-boot,bootcount-device property needs to point to the target device.
+
+Further configuration in the target device's node may be required
+(e.g. an offset into an I2C RTC's address space), depending on the
+UCLASS of the target device.
+
+Example
+-------
+/ {
+ chosen {
+ u-boot,bootcount-device = &rv3029;
+ };
+
+ i2c2 {
+ rv3029: rtc@56 {
+ compatible = "mc,rv3029";
+ reg = <0x56>;
+ u-boot,bootcount-offset = <0x38>;
+ };
+ };
+};
+
u-boot,spl-boot-order property
------------------------------
diff --git a/drivers/bootcount/Kconfig b/drivers/bootcount/Kconfig
index d335ed1..cdde7b5 100644
--- a/drivers/bootcount/Kconfig
+++ b/drivers/bootcount/Kconfig
@@ -70,6 +70,18 @@ config BOOTCOUNT_AT91
bool "Boot counter for Atmel AT91SAM9XE"
depends on AT91SAM9XE
+config BOOTCOUNT_DM
+ bool "Boot counter in a device-model device"
+ help
+ Enables reading/writing the bootcount in a device-model
+ device referenced from the /chosen node. The type of the
+ device is detected from DM and any additional configuration
+ information (e.g. the offset into a RTC device that supports
+ read32/write32) is read from the device's node.
+
+ At this time the following DM device classes are supported:
+ * RTC (using read32/write32)
+
endchoice
config BOOTCOUNT_ALEN
diff --git a/drivers/bootcount/Makefile b/drivers/bootcount/Makefile
index 68bc006..e8ed729 100644
--- a/drivers/bootcount/Makefile
+++ b/drivers/bootcount/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_BOOTCOUNT_RAM) += bootcount_ram.o
obj-$(CONFIG_BOOTCOUNT_ENV) += bootcount_env.o
obj-$(CONFIG_BOOTCOUNT_I2C) += bootcount_i2c.o
obj-$(CONFIG_BOOTCOUNT_EXT) += bootcount_ext.o
+obj-$(CONFIG_BOOTCOUNT_DM) += bootcount_dm.o
diff --git a/drivers/bootcount/bootcount_dm.c b/drivers/bootcount/bootcount_dm.c
new file mode 100644
index 0000000..99bdb88
--- /dev/null
+++ b/drivers/bootcount/bootcount_dm.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2018 Theobroma Systems Design und Consulting GmbH
+ */
+
+#include <common.h>
+#include <bootcount.h>
+#include <dm.h>
+#include <rtc.h>
+
+const u8 bootcount_magic = 0xbc;
+
+static void bootcount_store_rtc(struct udevice *dev, ulong a)
+{
+#if CONFIG_IS_ENABLED(DM_RTC)
+ u32 offset;
+ const char *offset_propname = "u-boot,bootcount-offset";
+ const u16 val = bootcount_magic << 8 | (a & 0xff);
+
+ if (dev_read_u32(dev, offset_propname, &offset) < 0) {
+ debug("%s: requires %s\n", __func__, offset_propname);
+ return;
+ }
+
+ if (rtc_write16(dev, offset, val) < 0) {
+ debug("%s: rtc_write16 failed\n", __func__);
+ return;
+ }
+#endif
+}
+
+static u32 bootcount_load_rtc(struct udevice *dev)
+{
+#if CONFIG_IS_ENABLED(DM_RTC)
+ u32 offset;
+ const char *offset_propname = "u-boot,bootcount-offset";
+ u16 val;
+
+ if (dev_read_u32(dev, offset_propname, &offset) < 0) {
+ debug("%s: requires %s\n", __func__, offset_propname);
+ goto fail;
+ }
+
+ if (rtc_read16(dev, offset, &val) < 0) {
+ debug("%s: rtc_write16 failed\n", __func__);
+ goto fail;
+ }
+
+ if (val >> 8 == bootcount_magic)
+ return val & 0xff;
+
+ debug("%s: bootcount magic does not match on %04x\n", __func__, val);
+ fail:
+#endif
+ return 0;
+}
+
+/* Now implement the generic default functions */
+void bootcount_store(ulong a)
+{
+ struct udevice *dev;
+ ofnode node;
+ const char *propname = "u-boot,bootcount-device";
+
+ node = ofnode_get_chosen_node(propname);
+ if (!ofnode_valid(node)) {
+ debug("%s: no '%s'\n", __func__, propname);
+ return;
+ }
+
+ /* RTC devices */
+ if (!uclass_get_device_by_ofnode(UCLASS_RTC, node, &dev))
+ return bootcount_store_rtc(dev, a);
+}
+
+ulong bootcount_load(void)
+{
+ struct udevice *dev;
+ ofnode node;
+ const char *propname = "u-boot,bootcount-device";
+
+ node = ofnode_get_chosen_node(propname);
+ if (!ofnode_valid(node)) {
+ debug("%s: no '%s'\n", __func__, propname);
+ return 0;
+ }
+
+ /* RTC devices */
+ if (!uclass_get_device_by_ofnode(UCLASS_RTC, node, &dev))
+ return bootcount_load_rtc(dev);
+
+ return 0;
+}
--
2.1.4
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