[U-Boot] [PATCH v2 16/19] armv7: support rk3066 early back to bootrom in vector.S

[Paweł Jarosz]

Rockchip bootrom first reads 1KB data from nand at offset 0x10080C00 and
executes it. Then waits for back to bootrom and loads another 32KB to sram
which also executes. Sdram initialisation code needs to be in one of these two
steps. Then bootloader loads another ~200KB of data at offset 0x60000000
and jumps to it.

32KB of data is a little low for tpl + spl part and ~200KB data is to low for
u-boot part(for example to boot from mmc you need to disable usb support.

My solution to size problem is to move sdram initialisation code to tpl stage,
move spl part to third stage(reading 200KB data) and add support for loading
u-boot by spl from ext2/4, fat partitions.

But moving sdram initialisation code to tpl increases size of tpl above 1KB
(first boot stage). Solution to this is to add code which will be below 1KB
offset in tpl binary and do back to bootrom at very beginning of the tpl
execution.

Adding this few lines of code here meets these conditions.

Signed-off-by: Paweł Jarosz <paweljarosz3691 at gmail.com>
Acked-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
---
Changes since v1:
- moved to vector.S

 arch/arm/include/asm/arch-rockchip/boot0.h | 14 ++++++++++++++
 arch/arm/lib/vectors.S                     | 18 +++++++++---------
 configs/mk808_defconfig                    |  1 +
 3 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/arch/arm/include/asm/arch-rockchip/boot0.h b/arch/arm/include/asm/arch-rockchip/boot0.h
index 72d264b..4179448 100644
--- a/arch/arm/include/asm/arch-rockchip/boot0.h
+++ b/arch/arm/include/asm/arch-rockchip/boot0.h
@@ -5,6 +5,19 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 
+#if defined(CONFIG_ROCKCHIP_RK3066) && defined(CONFIG_TPL_BUILD)
+	ldr	r3, =0x10080900
+	ldr	r0, [r3]
+	cmp	r0, #1
+	movne	r0, #1
+	strne	r0, [r3]
+	beq	out_of_bootrom
+	bx	lr
+out_of_bootrom:
+	mov	r0, #0
+	str	r0, [r3]
+#endif
+
 /*
  * Execution starts on the instruction following this 4-byte header
  * (containing the magic 'RK33').
@@ -26,6 +39,7 @@
 	 */
 	b reset	 /* may be overwritten --- should be 'nop' or a 'b reset' */
 #endif
+
 	b reset
 
 #if defined(CONFIG_ROCKCHIP_RK3399) && defined(CONFIG_SPL_BUILD)
diff --git a/arch/arm/lib/vectors.S b/arch/arm/lib/vectors.S
index 1019091..e3c18da 100644
--- a/arch/arm/lib/vectors.S
+++ b/arch/arm/lib/vectors.S
@@ -47,6 +47,15 @@
 
 _start:
 
+#ifdef CONFIG_ENABLE_ARM_SOC_BOOT0_HOOK
+/*
+ * Various SoCs need something special and SoC-specific up front in
+ * order to boot, allow them to set that in their boot0.h file and then
+ * use it here.
+ */
+#include <asm/arch/boot0.h>
+#endif
+
 #ifdef CONFIG_SYS_DV_NOR_BOOT_CFG
 	.word	CONFIG_SYS_DV_NOR_BOOT_CFG
 #endif
@@ -60,15 +69,6 @@ _start:
 	ldr	pc, _irq
 	ldr	pc, _fiq
 
-#ifdef CONFIG_ENABLE_ARM_SOC_BOOT0_HOOK
-/*
- * Various SoCs need something special and SoC-specific up front in
- * order to boot, allow them to set that in their boot0.h file and then
- * use it here.
- */
-#include <asm/arch/boot0.h>
-#endif
-
 /*
  *************************************************************************
  *
diff --git a/configs/mk808_defconfig b/configs/mk808_defconfig
index ab67e4f..bf4af82 100644
--- a/configs/mk808_defconfig
+++ b/configs/mk808_defconfig
@@ -13,6 +13,7 @@ CONFIG_USE_PRIVATE_LIBGCC=y
 CONFIG_CMD_DHRYSTONE=y
 CONFIG_ERRNO_STR=y
 CONFIG_SYS_NS16550=y
+CONFIG_ENABLE_ARM_SOC_BOOT0_HOOK=y
 CONFIG_BOOTDELAY=1
 CONFIG_CONSOLE_MUX=y
 CONFIG_DISPLAY_BOARDINFO=y
-- 
2.7.4