am335x, guardian: software update available status is stored in AM3352 RTC scracth register

RTC second scratch register[32-bit]:
  -zero byte hold boot count value
  -first byte hold update available state
  -second byte hold version
  -third byte hold magic number

Signed-off-by: Gireesh Hiremath <Gireesh.Hiremath@in.bosch.com>

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Link: https://lore.kernel.org/r/20210611161350.2141-17-Gireesh.Hiremath@in.bosch.com
Gbp-Pq: Topic apertis/guardian
Gbp-Pq: Name am335x-guardian-software-update-available-status-is-store.patch

3 files changed, 89 insertions, 3 deletions

diff --git a/drivers/bootcount/Kconfig b/drivers/bootcount/Kconfig
index b5ccea0d9c..0de2b7bd78 100644
--- a/drivers/bootcount/Kconfig
+++ b/drivers/bootcount/Kconfig
@@ -42,6 +42,25 @@ config BOOTCOUNT_AM33XX
 	  This requires the RTC clocks, etc, to be enabled prior to use and
 	  not all boards with this IP block on it will have the RTC in use.
 
+config BOOTCOUNT_AM33XX_NVMEM
+	bool "Boot counter in AM33XX RTC IP block with upgrade_available flag"
+	depends on AM33XX
+        select SPL_AM33XX_ENABLE_RTC32K_OSC if AM33XX
+	help
+	  Add support for maintaining bootcount,upgrade_available,
+	  version and BOOTMAGIC in a AM33xx RTC IP block
+	  scratch register2.
+
+	  A bootcount driver for the RTC IP block found on many TI platforms.
+	  This requires the RTC clocks, etc, to be enabled prior to use and
+	  not all boards with this IP block on it will have the RTC in use.
+
+	  If there is upgrade in software then "upgrade_available" is 1,
+	  "bootcount" is incremented otherwise "upgrade_available" and
+	  "bootcount" is  always 0. So the Userspace Application must set
+	  the "upgrade_available" and "bootcount" variable to 0, if a boot
+	  was successfully.
+
 config BOOTCOUNT_ENV
 	bool "Boot counter in environment"
 	help
@@ -177,16 +196,25 @@ config SYS_BOOTCOUNT_EXT_NAME
 
 config SYS_BOOTCOUNT_ADDR
 	hex "RAM address used for reading and writing the boot counter"
-	default 0x44E3E000 if BOOTCOUNT_AM33XX
+	default 0x44E3E000 if BOOTCOUNT_AM33XX || BOOTCOUNT_AM33XX_NVMEM
 	default 0xE0115FF8 if ARCH_LS1043A || ARCH_LS1021A
 	depends on BOOTCOUNT_AM33XX || BOOTCOUNT_GENERIC || BOOTCOUNT_EXT || \
-		   BOOTCOUNT_I2C
+		   BOOTCOUNT_I2C || BOOTCOUNT_AM33XX_NVMEM
 	help
 	  Set the address used for reading and writing the boot counter.
 
 config SYS_BOOTCOUNT_MAGIC
 	hex "Magic value for the boot counter"
-	default 0xB001C041
+	default 0xB001C041 if BOOTCOUNT_GENERIC || BOOTCOUNT_EXT || \
+			      BOOTCOUNT_AM33XX || BOOTCOUNT_ENV || \
+			      BOOTCOUNT_RAM || BOOTCOUNT_I2C || \
+			      BOOTCOUNT_AT91 || DM_BOOTCOUNT
+	default 0xB0 if BOOTCOUNT_AM33XX_NVMEM
+	depends on BOOTCOUNT_GENERIC || BOOTCOUNT_EXT || \
+		   BOOTCOUNT_AM33XX || BOOTCOUNT_ENV || \
+		   BOOTCOUNT_RAM || BOOTCOUNT_I2C || \
+		   BOOTCOUNT_AT91 || DM_BOOTCOUNT || \
+		   BOOTCOUNT_AM33XX_NVMEM
 	help
 	  Set the magic value used for the boot counter.
 
diff --git a/drivers/bootcount/Makefile b/drivers/bootcount/Makefile
index 51d860b00e..12658ffdce 100644
--- a/drivers/bootcount/Makefile
+++ b/drivers/bootcount/Makefile
@@ -8,6 +8,7 @@ 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_AM33XX_NVMEM)	+= bootcount_nvmem.o
 
 obj-$(CONFIG_DM_BOOTCOUNT)      += bootcount-uclass.o
 obj-$(CONFIG_DM_BOOTCOUNT_RTC)  += rtc.o
diff --git a/drivers/bootcount/bootcount_nvmem.c b/drivers/bootcount/bootcount_nvmem.c
new file mode 100644
index 0000000000..5f266d5ec8
--- /dev/null
+++ b/drivers/bootcount/bootcount_nvmem.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2011
+ * Heiko Schocher, DENX Software Engineering, hs@denx.de.
+ * (C) Copyright 2018 Robert Bosch Power Tools GmbH.
+ *
+ * A bootcount driver for the RTC IP block found on many TI platforms.
+ * This requires the RTC clocks, etc, to be enabled prior to use and
+ * not all boards with this IP block on it will have the RTC in use.
+ */
+
+#include <bootcount.h>
+#include <asm/davinci_rtc.h>
+
+#define	BC_VERSION	2
+
+void bootcount_store(ulong bootcount)
+{
+	u8 upgrade_available = 0;
+	ulong val = 0;
+	struct davinci_rtc *reg =
+		(struct davinci_rtc *)CONFIG_SYS_BOOTCOUNT_ADDR;
+
+	val = raw_bootcount_load(&reg->scratch2);
+	upgrade_available = (val >> 8) & 0x000000ff;
+
+	/* Only update bootcount during upgrade process */
+	if (!upgrade_available)
+		bootcount = 0;
+
+	val = (bootcount & 0x000000ff) |
+	      (upgrade_available << 8) |
+	      (BC_VERSION << 16) |
+	      (CONFIG_SYS_BOOTCOUNT_MAGIC << 24);
+
+	/*
+	 * write RTC kick registers to enable write
+	 * for RTC Scratch registers. Scratch register 2 is
+	 * used for bootcount value.
+	 */
+	writel(RTC_KICK0R_WE, &reg->kick0r);
+	writel(RTC_KICK1R_WE, &reg->kick1r);
+	raw_bootcount_store(&reg->scratch2, val);
+}
+
+ulong bootcount_load(void)
+{
+	unsigned long val = 0;
+	struct davinci_rtc *reg =
+		(struct davinci_rtc *)CONFIG_SYS_BOOTCOUNT_ADDR;
+
+	val = raw_bootcount_load(&reg->scratch2);
+	if ((val >> 24) != CONFIG_SYS_BOOTCOUNT_MAGIC)
+		return 0;
+	else
+		return val & 0x000000ff;
+}