[U-Boot] [PATCH 3/3] bootcount: add DM-based backing store for bootcount
Lukasz Majewski
lukma at denx.de
Tue Aug 14 11:10:13 UTC 2018
Hi Philipp,
> 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.tomsich at theobroma-systems.com>
> Tested-by: Klaus Goger <klaus.goger at 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 at 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;
> +}
Thanks for your patch.
However, if I may ask - would it be possible to add support for EEPROM
based bootcount in an easy way?
I mean - do you think that it would be feasible to have
bootcount-uclass, which would support generic load/store functions with
DM drivers for RTC, EEPROM or even simple write to SFR registers (as it
is just an offset in the end)?
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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