bootcount: add uclass for bootcount

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.
If ambiguous (i.e. multiple bootcount-devices are present) the
/chosen/u-boot,bootcount-device property can be used to select one
bootcount device.

Initially, this provides support for the following DM devices:
 * RTC devices

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Tested-by: Klaus Goger <klaus.goger@theobroma-systems.com>

diff --git a/doc/device-tree-bindings/chosen.txt b/doc/device-tree-bindings/chosen.txt
index 86c533ad6d3588b51656e944e635d3ca08262aab..395c9501e3bdafd01ffac650e7cab7b3c0f8c3f9 100644 (file)
--- a/doc/device-tree-bindings/chosen.txt
+++ b/doc/device-tree-bindings/chosen.txt
@@ -42,6 +42,36 @@ 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) managed by a device conforming to UCLASS_BOOTCOUNT.  If
+multiple such devices are present in a system concurrently, then the
+u-boot,bootcount-device property can select the preferred target.
+
+Example
+-------
+/ {
+       chosen {
+               u-boot,bootcount-device = &bootcount-rv3029;
+       };
+
+       bootcount-rv3029: bootcount@0 {
+               compatible = "u-boot,bootcount-rtc";
+               rtc = &rv3029;
+               offset = <0x38>;
+       };
+
+       i2c2 {
+               rv3029: rtc@56 {
+                               compatible = "mc,rv3029";
+                               reg = <0x56>;
+               };
+       };
+};
+
 u-boot,spl-boot-order property
 ------------------------------
 

diff --git a/drivers/bootcount/Kconfig b/drivers/bootcount/Kconfig
index 67033637c0d6bcf5bd01c96c5e8a81f8d66d418e..46571eb322930bcd28852cb16488f8b7fe53640a 100644 (file)
--- a/drivers/bootcount/Kconfig
+++ b/drivers/bootcount/Kconfig
@@ -70,6 +70,14 @@ config BOOTCOUNT_AT91
        bool "Boot counter for Atmel AT91SAM9XE"
        depends on AT91SAM9XE
 
+config DM_BOOTCOUNT
+        bool "Boot counter in a device-model device"
+       help
+         Enables reading/writing the bootcount in a device-model based
+         backing store.  If an entry in /chosen/u-boot,bootcount-device
+         exists, this will be the preferred bootcount device; otherwise
+         the first available bootcount device will be used.
+
 endchoice
 
 config BOOTCOUNT_BOOTLIMIT

diff --git a/drivers/bootcount/Makefile b/drivers/bootcount/Makefile
index 68bc006b75334c4037a39eb243bdb3f9bcb9b3ee..81980b3cadd2b3da5ba927977c05f8a6d954d6f8 100644 (file)
--- a/drivers/bootcount/Makefile
+++ b/drivers/bootcount/Makefile
@@ -7,3 +7,5 @@ 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_DM_BOOTCOUNT)      += bootcount-uclass.o

diff --git a/drivers/bootcount/bootcount-uclass.c b/drivers/bootcount/bootcount-uclass.c
new file mode 100644 (file)
index 0000000..0689db7
--- /dev/null
+++ b/drivers/bootcount/bootcount-uclass.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2018 Theobroma Systems Design und Consulting GmbH
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <bootcount.h>
+
+int dm_bootcount_get(struct udevice *dev, u32 *bootcount)
+{
+       struct bootcount_ops *ops = bootcount_get_ops(dev);
+
+       assert(ops);
+       if (!ops->get)
+               return -ENOSYS;
+       return ops->get(dev, bootcount);
+}
+
+int dm_bootcount_set(struct udevice *dev, const u32 bootcount)
+{
+       struct bootcount_ops *ops = bootcount_get_ops(dev);
+
+       assert(ops);
+       if (!ops->set)
+               return -ENOSYS;
+       return ops->set(dev, bootcount);
+}
+
+/* Now implement the generic default functions */
+void bootcount_store(ulong val)
+{
+       struct udevice *dev = NULL;
+       ofnode node;
+       const char *propname = "u-boot,bootcount-device";
+       int ret = -ENODEV;
+
+       /*
+        * If there's a preferred bootcount device selected by the user (by
+        * setting '/chosen/u-boot,bootcount-device' in the DTS), try to use
+        * it if available.
+        */
+       node = ofnode_get_chosen_node(propname);
+       if (ofnode_valid(node))
+               ret = uclass_get_device_by_ofnode(UCLASS_BOOTCOUNT, node, &dev);
+
+       /* If there was no user-selected device, use the first available one */
+       if (ret)
+               ret = uclass_get_device(UCLASS_BOOTCOUNT, 0, &dev);
+
+       if (dev)
+               ret = dm_bootcount_set(dev, val);
+
+       if (ret)
+               pr_debug("%s: failed to store 0x%lx\n", __func__, val);
+}
+
+ulong bootcount_load(void)
+{
+       struct udevice *dev = NULL;
+       ofnode node;
+       const char *propname = "u-boot,bootcount-device";
+       int ret = -ENODEV;
+       u32 val;
+
+       /*
+        * If there's a preferred bootcount device selected by the user (by
+        * setting '/chosen/u-boot,bootcount-device' in the DTS), try to use
+        * it if available.
+        */
+       node = ofnode_get_chosen_node(propname);
+       if (ofnode_valid(node))
+               ret = uclass_get_device_by_ofnode(UCLASS_BOOTCOUNT, node, &dev);
+
+       /* If there was no user-selected device, use the first available one */
+       if (ret)
+               ret = uclass_get_device(UCLASS_BOOTCOUNT, 0, &dev);
+
+       if (dev)
+               ret = dm_bootcount_get(dev, &val);
+
+       if (ret)
+               pr_debug("%s: failed to load bootcount\n", __func__);
+
+       /* Return the 0, if the call to dm_bootcount_get failed */
+       return ret ? 0 : val;
+}
+
+UCLASS_DRIVER(bootcount) = {
+       .name           = "bootcount",
+       .id             = UCLASS_BOOTCOUNT,
+};

diff --git a/include/bootcount.h b/include/bootcount.h
index 671adcc4101adb7c192fb0cb2ab7898f60e25b31..daee84316c7f5f7594f6eceace9d06225c4bbd89 100644 (file)
--- a/include/bootcount.h
+++ b/include/bootcount.h
@@ -10,6 +10,54 @@
 #include <asm/io.h>
 #include <asm/byteorder.h>
 
+#ifdef CONFIG_DM_BOOTCOUNT
+
+struct bootcount_ops {
+       /**
+        * get() - get the current bootcount value
+        *
+        * Returns the current counter value of the bootcount backing
+        * store.
+        *
+        * @dev:        Device to read from
+        * @bootcount:  Address to put the current bootcount value
+        */
+       int (*get)(struct udevice *dev, u32 *bootcount);
+
+       /**
+        * set() - set a bootcount value (e.g. to reset or increment)
+        *
+        * Sets the value in the bootcount backing store.
+        *
+        * @dev:        Device to read from
+        * @bootcount:  New bootcount value to store
+        */
+       int (*set)(struct udevice *dev, const u32 bootcount);
+};
+
+/* Access the operations for a bootcount device */
+#define bootcount_get_ops(dev) ((struct bootcount_ops *)(dev)->driver->ops)
+
+/**
+ * dm_bootcount_get() - Read the current value from a bootcount storage
+ *
+ * @dev:       Device to read from
+ * @bootcount: Place to put the current bootcount
+ * @return 0 if OK, -ve on error
+ */
+int dm_bootcount_get(struct udevice *dev, u32 *bootcount);
+
+/**
+ * dm_bootcount_set() - Write a value to a bootcount storage
+ *
+ * @dev:       Device to read from
+ * @bootcount:  Value to be written to the backing storage
+ * @return 0 if OK, -ve on error
+ */
+int dm_bootcount_set(struct udevice *dev, u32 bootcount);
+
+#endif
+
 #if defined(CONFIG_SPL_BOOTCOUNT_LIMIT) || defined(CONFIG_BOOTCOUNT_LIMIT)
 
 #if !defined(CONFIG_SYS_BOOTCOUNT_LE) && !defined(CONFIG_SYS_BOOTCOUNT_BE)

diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 037af0460c6d2e901fe448df7039255ebd12f2b7..bbe842e59ab1ef7d18a48a965f639731206a80f0 100644 (file)
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -32,6 +32,7 @@ enum uclass_id {
        UCLASS_AXI,             /* AXI bus */
        UCLASS_BLK,             /* Block device */
        UCLASS_BOARD,           /* Device information from hardware */
+       UCLASS_BOOTCOUNT,       /* Bootcount backing store */
        UCLASS_CLK,             /* Clock source, e.g. used by peripherals */
        UCLASS_CPU,             /* CPU, typically part of an SoC */
        UCLASS_CROS_EC,         /* Chrome OS EC */