From 5ed95fa7b60cd53f10edce2561a7fef7787aba29 Mon Sep 17 00:00:00 2001
From: =?utf8?q?=C5=81ukasz=20Stelmach?= <l.stelmach@samsung.com>
Date: Tue, 10 Oct 2017 13:11:54 +0200
Subject: [PATCH] rpi: Read the value of RSTS register
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RSTS register allows passing information from OS too bootloader upon
reboot.

Change-Id: I2fa04fa0e63e5c81f78901c06ca8884f7e89f8e8
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
---
 arch/arm/mach-bcm283x/include/mach/mbox.h | 14 ++++++++
 board/raspberrypi/rpi/rpi.c               | 56 +++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/arch/arm/mach-bcm283x/include/mach/mbox.h b/arch/arm/mach-bcm283x/include/mach/mbox.h
index 2ae2d3d..7063163 100644
--- a/arch/arm/mach-bcm283x/include/mach/mbox.h
+++ b/arch/arm/mach-bcm283x/include/mach/mbox.h
@@ -504,6 +504,20 @@ struct bcm2835_mbox_tag_pci_dev_addr {
 	} body;
 };
 
+#define BCM2835_MBOX_TAG_GET_RSTS		0x00040011
+
+struct bcm2835_mbox_tag_get_rsts {
+	struct bcm2835_mbox_tag_hdr tag_hdr;
+	union {
+		struct {
+		} req;
+		struct {
+			u32 rsts;
+		} resp;
+	} body;
+};
+
+
 /*
  * Pass a raw u32 message to the VC, and receive a raw u32 back.
  *
diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
index 372b26b..b8f5b6e 100644
--- a/board/raspberrypi/rpi/rpi.c
+++ b/board/raspberrypi/rpi/rpi.c
@@ -65,6 +65,34 @@ struct msg_get_clock_rate {
 	u32 end_tag;
 };
 
+struct msg_get_rsts {
+	struct bcm2835_mbox_hdr hdr;
+	struct bcm2835_mbox_tag_get_rsts get_rsts;
+	u32 end_tag;
+};
+
+/* Dump a message. */
+#ifdef BCM2835_MBOX_DUMP_MESSAGES
+#define BCM2835_MBOX_DUMP_MSG(msg) {					\
+		u32 *p = msg;						\
+		int i;							\
+		printf("%s:%d", __func__, __LINE__);			\
+		if (msg->hdr.code == 0)					\
+			printf("  req");				\
+		else if (msg->hdr.code == 0x80000000)			\
+			printf(" resp");				\
+		else if (msg->hdr.code == 0x80000000)			\
+			printf("  err");				\
+		else							\
+			printf(" WAT‽");				\
+		for (i = 0; i < sizeof(*(msg)) / sizeof(*p); i++)	\
+			printf(" 0x%08X", p[i]);			\
+		printf("\n");						\
+}
+#else
+#define BCM2835_MBOX_DUMP_MSG(msg)
+#endif
+
 #ifdef CONFIG_ARM64
 #define DTB_DIR "broadcom/"
 #else
@@ -337,6 +365,33 @@ unsigned long board_get_usable_ram_top(unsigned long total_size)
 	return fw_dtb_pointer & ~0xffff;
 }
 
+static void get_rsts(void)
+{
+	ALLOC_CACHE_ALIGN_BUFFER(struct msg_get_rsts, msg, 1);
+	int ret;
+	char rsts_string[11] = { 0 };
+
+	BCM2835_MBOX_INIT_HDR(msg);
+	BCM2835_MBOX_INIT_TAG(&msg->get_rsts, GET_RSTS);
+
+	BCM2835_MBOX_DUMP_MSG(msg);
+
+	ret = bcm2835_mbox_call_prop(BCM2835_MBOX_PROP_CHAN, &msg->hdr);
+	if (ret) {
+		printf("bcm2835: Could not query RSTS value\n");
+		/* Ignore the error, let's carry on. */
+		return;
+	}
+
+	BCM2835_MBOX_DUMP_MSG(msg);
+
+	snprintf(rsts_string, sizeof(rsts_string), "0x%08X",
+		 msg->get_rsts.body.resp.rsts);
+	env_set("reg_rsts", rsts_string);
+
+	return;
+}
+
 static void set_usbethaddr(void)
 {
 	ALLOC_CACHE_ALIGN_BUFFER(struct msg_get_mac_address, msg, 1);
@@ -411,6 +466,7 @@ int misc_init_r(void)
 	set_fdt_addr();
 	set_fdtfile();
 	set_usbethaddr();
+	get_rsts();
 #ifdef CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
 	set_board_info();
 #endif
-- 
2.7.4