[PATCH] drivers, char: add U-Boot bootcount driver
Heiko Schocher
hs at denx.de
Sun Dec 4 20:45:21 EST 2011
This driver implements the Linux kernel half of the boot count feature -
the boot counter can only be reset after it is clear that the
application has been started and is running correctly, which usually
can only be determined by the application code itself. Thus the reset
of the boot counter must be done by application code, which thus needs
an appropriate driver.
Required feature by the Carrier Grade Linux Requirements Definition;
see for example document "Carrier Grade Linux Requirements Definition
Overview V3.0" at
http://www.linuxfoundation.org/collaborate/workgroups/cgl/requirements#SMM.6.0_Boot_Cycle_Detection
Description: OSDL CGL specifies that carrier grade Linux
shall provide support for detecting a repeating reboot cycle
due to recurring failures. This detection should happen in
user space before system services are started.
This driver provides read/write access to the U-Boot bootcounter
through PROC FS and/or sysFS file.
The bootcountregister gets configured via DTS.
for example on the enbw_cmc board:
bootcount at 0x23060 {
compatible = "uboot,bootcount";
reg = <0x23060 0x20>;
};
original post from:
http://old.nabble.com/-POWERPC--add-U-Boot-bootcount-driver.-td26804029.html
Signed-off-by: Heiko Schocher <hs at denx.de>
Cc: Wolfgang Denk <wd at denx.de>
Cc: Vitaly Bordug <vbordug at ru.mvista.com>
Cc: devicetree-discuss at lists.ozlabs.org
Cc: linux-kernel at vger.kernel.org
---
.../devicetree/bindings/char/bootcount.txt | 13 ++
drivers/char/Kconfig | 7 +
drivers/char/Makefile | 1 +
drivers/char/bootcount.c | 210 ++++++++++++++++++++
4 files changed, 231 insertions(+), 0 deletions(-)
create mode 100644 Documentation/devicetree/bindings/char/bootcount.txt
create mode 100644 drivers/char/bootcount.c
diff --git a/Documentation/devicetree/bindings/char/bootcount.txt b/Documentation/devicetree/bindings/char/bootcount.txt
new file mode 100644
index 0000000..079a7da
--- /dev/null
+++ b/Documentation/devicetree/bindings/char/bootcount.txt
@@ -0,0 +1,13 @@
+Bootcount driver
+
+Required properties:
+
+ - compatible : should be "uboot,bootcount"
+ - reg: the address of the bootcounter
+
+Example:
+
+bootcount at 1c23000 {
+ compatible = "uboot,bootcount";
+ reg = <0x23060 0x20>;
+};
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 4364303..9c5ccab 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -577,6 +577,13 @@ config UV_MMTIMER
The uv_mmtimer device allows direct userspace access to the
UV system timer.
+config BOOTCOUNT
+ tristate "U-Boot Bootcount driver"
+ depends on OF
+ help
+ The U-Boot Bootcount driver allows to access the
+ bootcounter through procFS or sysFS files.
+
source "drivers/char/tpm/Kconfig"
config TELCLOCK
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 32762ba..a91e18e 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -49,6 +49,7 @@ obj-$(CONFIG_PC8736x_GPIO) += pc8736x_gpio.o
obj-$(CONFIG_NSC_GPIO) += nsc_gpio.o
obj-$(CONFIG_GPIO_TB0219) += tb0219.o
obj-$(CONFIG_TELCLOCK) += tlclk.o
+obj-$(CONFIG_BOOTCOUNT) += bootcount.o
obj-$(CONFIG_MWAVE) += mwave/
obj-$(CONFIG_AGP) += agp/
diff --git a/drivers/char/bootcount.c b/drivers/char/bootcount.c
new file mode 100644
index 0000000..0ee457f
--- /dev/null
+++ b/drivers/char/bootcount.c
@@ -0,0 +1,210 @@
+/*
+ * This driver gives access(read/write) to the bootcounter used by u-boot.
+ * Access is supported via procFS and sysFS.
+ *
+ * Copyright 2008 DENX Software Engineering GmbH
+ * Author: Heiko Schocher <hs at denx.de>
+ * Based on work from: Steffen Rumler (Steffen.Rumler at siemens.com)
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/capability.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/ptrace.h>
+#include <linux/uaccess.h>
+
+#ifndef CONFIG_PROC_FS
+#error "PROC FS support must be switched-on"
+#endif
+#include <linux/proc_fs.h>
+
+#define UBOOT_BOOTCOUNT_MAGIC_OFFSET 0x04 /* offset of magic number */
+#define UBOOT_BOOTCOUNT_MAGIC 0xB001C041 /* magic number value */
+
+#define UBOOT_BOOTCOUNT_PROC_ENTRY "driver/bootcount"
+
+/*
+ * This macro frees the machine specific function from bounds checking and
+ * this like that...
+ */
+#define PRINT_PROC(fmt, args...) \
+ do { \
+ *len += sprintf(buffer + *len, fmt, ##args); \
+ if (*begin + *len > offset + size) \
+ return 0; \
+ if (*begin + *len < offset) { \
+ *begin += *len; \
+ *len = 0; \
+ } \
+ } while (0)
+
+void __iomem *mem;
+/*
+ * read U-Boot bootcounter
+ */
+static int
+read_bootcounter_info(char *buffer, int *len, off_t * begin, off_t offset,
+ int size)
+{
+ unsigned long magic;
+ unsigned long counter;
+
+
+ magic = be32_to_cpu(readl(mem + UBOOT_BOOTCOUNT_MAGIC_OFFSET));
+ counter = be32_to_cpu(readl(mem));
+
+ if (magic == UBOOT_BOOTCOUNT_MAGIC) {
+ PRINT_PROC("%lu\n", counter);
+ } else {
+ PRINT_PROC("bad magic: 0x%lu != 0x%lu\n", magic,
+ (unsigned long)UBOOT_BOOTCOUNT_MAGIC);
+ }
+
+ return 1;
+}
+
+/*
+ * read U-Boot bootcounter (wrapper)
+ */
+static int
+read_bootcounter(char *buffer, char **start, off_t offset, int size,
+ int *eof, void *arg)
+{
+ int len = 0;
+ off_t begin = 0;
+
+
+ *eof = read_bootcounter_info(buffer, &len, &begin, offset, size);
+
+ if (offset >= begin + len)
+ return 0;
+
+ *start = buffer + (offset - begin);
+ return size < begin + len - offset ? size : begin + len - offset;
+}
+
+/*
+ * write new value to U-Boot bootcounter
+ */
+static int
+write_bootcounter(struct file *file, const char *buffer, unsigned long count,
+ void *data)
+{
+ unsigned long magic;
+
+ magic = be32_to_cpu(readl(mem + UBOOT_BOOTCOUNT_MAGIC_OFFSET));
+ if (magic == UBOOT_BOOTCOUNT_MAGIC)
+ writel(cpu_to_be32(simple_strtol(buffer, NULL, 10)), mem);
+ else
+ return -EINVAL;
+
+ return count;
+}
+
+/* helper for the sysFS */
+static int show_str_bootcount(struct device *device,
+ struct device_attribute *attr,
+ char *buf)
+{
+ int ret = 0;
+ off_t begin = 0;
+
+ read_bootcounter_info(buf, &ret, &begin, 0, 20);
+ return ret;
+}
+static int store_str_bootcount(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t count)
+{
+ write_bootcounter(NULL, buf, count, NULL);
+ return count;
+}
+static DEVICE_ATTR(bootcount, S_IWUSR | S_IRUGO, show_str_bootcount,
+ store_str_bootcount);
+
+static int __devinit bootcount_probe(struct platform_device *ofdev)
+{
+ struct device_node *np = of_node_get(ofdev->dev.of_node);
+ struct proc_dir_entry *bootcount;
+
+ mem = of_iomap(np, 0);
+ if (mem == NULL)
+ dev_err(&ofdev->dev, "%s couldnt map register.\n", __func__);
+
+ /* init ProcFS */
+ bootcount = create_proc_entry(UBOOT_BOOTCOUNT_PROC_ENTRY, 0600, NULL);
+ if (bootcount == NULL) {
+ dev_err(&ofdev->dev, "\n%s (%d): cannot create /proc/%s\n",
+ __FILE__, __LINE__, UBOOT_BOOTCOUNT_PROC_ENTRY);
+ } else {
+
+ bootcount->read_proc = read_bootcounter;
+ bootcount->write_proc = write_bootcounter;
+ dev_info(&ofdev->dev, "created \"/proc/%s\"\n",
+ UBOOT_BOOTCOUNT_PROC_ENTRY);
+ }
+
+ if (device_create_file(&ofdev->dev, &dev_attr_bootcount))
+ dev_warn(&ofdev->dev, "%s couldnt register sysFS entry.\n",
+ __func__);
+
+ return 0;
+}
+
+static int __devexit bootcount_remove(struct platform_device *ofdev)
+{
+ BUG();
+ return 0;
+}
+
+static const struct of_device_id __devinitconst bootcount_match[] = {
+ {
+ .compatible = "uboot,bootcount",
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, bootcount_match);
+
+static struct platform_driver bootcount_driver = {
+ .driver = {
+ .name = "bootcount",
+ .of_match_table = bootcount_match,
+ .owner = THIS_MODULE,
+ },
+ .probe = bootcount_probe,
+ .remove = bootcount_remove,
+};
+
+
+static int __init uboot_bootcount_init(void)
+{
+ return platform_driver_register(&bootcount_driver);
+}
+
+static void __exit uboot_bootcount_cleanup(void)
+{
+ if (mem != NULL)
+ iounmap(mem);
+ remove_proc_entry(UBOOT_BOOTCOUNT_PROC_ENTRY, NULL);
+}
+
+module_init(uboot_bootcount_init);
+module_exit(uboot_bootcount_cleanup);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Steffen Rumler <steffen.rumler at siemens.com>");
+MODULE_DESCRIPTION("Provide (read/write) access to the U-Boot bootcounter via PROC FS");
--
1.7.6.4
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