sunxi: retrieve FEL-provided values to environment variables

This patch extends the misc_init_r() function on sunxi boards
to test for the presence of a suitable "sunxi" SPL header. If
found, and the loader ("fel" utility) provided a non-zero value
for the boot.scr address, then the corresponding environment
variable fel_scriptaddr gets set.

misc_init_r() also sets (or clears) the "fel_booted" variable depending
on the active boot device, using the same logic as spl_boot_device().

The goal is to provide sufficient information (within the U-Boot
environment) to make intelligent decisions on how to continue the boot
process, allowing specific customizations for the "FEL boot" case.

Signed-off-by: Bernhard Nortmann <bernhard.nortmann@web.de>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

arch/arm/cpu/armv7/sunxi/board.c

@@ -21,6 +21,7 @@
 #include <asm/io.h>
 #include <asm/arch/clock.h>
 #include <asm/arch/gpio.h>
+#include <asm/arch/spl.h>
 #include <asm/arch/sys_proto.h>
 #include <asm/arch/timer.h>
 #include <asm/arch/tzpc.h>
@@ -152,7 +153,7 @@ u32 spl_boot_device(void)
 	 * binary over USB. If it is found, it determines where SPL was
 	 * read from.
 	 */
-	if (readl(4) != 0x4E4F4765 || readl(8) != 0x3054422E) /* eGON.BT0 */
+	if (!is_boot0_magic(SPL_ADDR + 4)) /* eGON.BT0 */
 		return BOOT_DEVICE_BOARD;
 
 	/* The BROM will try to boot from mmc0 first, so try that first. */

arch/arm/include/asm/arch-sunxi/spl.h

@@ -12,6 +12,9 @@
 #define SPL_SIGNATURE		"SPL" /* marks "sunxi" SPL header */
 #define SPL_HEADER_VERSION	1
 
+/* Note: A80 will require special handling here: SPL_ADDR 0x10000 */
+#define SPL_ADDR		0x0
+
 /* boot head definition from sun4i boot code */
 struct boot_file_head {
 	uint32_t b_instruction;	/* one intruction jumping to real code */
@@ -42,4 +45,6 @@ struct boot_file_head {
 	uint32_t reserved;		/* padding, align to 32 bytes */
 };
 
+#define is_boot0_magic(addr)	(memcmp((void *)addr, BOOT0_MAGIC, 8) == 0)
+
 #endif

board/sunxi/board.c

@@ -516,6 +516,31 @@ void get_board_serial(struct tag_serialnr *serialnr)
 }
 #endif
 
+#if !defined(CONFIG_SPL_BUILD)
+#include <asm/arch/spl.h>
+
+/*
+ * Check the SPL header for the "sunxi" variant. If found: parse values
+ * that might have been passed by the loader ("fel" utility), and update
+ * the environment accordingly.
+ */
+static void parse_spl_header(const uint32_t spl_addr)
+{
+	struct boot_file_head *spl = (void *)spl_addr;
+	if (memcmp(spl->spl_signature, SPL_SIGNATURE, 3) == 0) {
+		uint8_t spl_header_version = spl->spl_signature[3];
+		if (spl_header_version == SPL_HEADER_VERSION) {
+			if (spl->fel_script_address)
+				setenv_hex("fel_scriptaddr",
+					   spl->fel_script_address);
+			return;
+		}
+		printf("sunxi SPL version mismatch: expected %u, got %u\n",
+		       SPL_HEADER_VERSION, spl_header_version);
+	}
+}
+#endif
+
 #ifdef CONFIG_MISC_INIT_R
 int misc_init_r(void)
 {
@@ -524,6 +549,16 @@ int misc_init_r(void)
 	uint8_t mac_addr[6];
 	int ret;
 
+#if !defined(CONFIG_SPL_BUILD)
+	setenv("fel_booted", NULL);
+	setenv("fel_scriptaddr", NULL);
+	/* determine if we are running in FEL mode */
+	if (!is_boot0_magic(SPL_ADDR + 4)) { /* eGON.BT0 */
+		setenv("fel_booted", "1");
+		parse_spl_header(SPL_ADDR);
+	}
+#endif
+
 	ret = sunxi_get_sid(sid);
 	if (ret == 0 && sid[0] != 0 && sid[3] != 0) {
 		if (!getenv("ethaddr")) {