arm: mvebu: Add option to use UART xmodem protocol via kwboot

This patch enables the use of the kwboot tool, to boot mainline U-Boot
on the Marvell Armada XP/38x SoC's. This is done by returning to the
SoC's BootROM after SPL has initialized the SDRAM. We need to make sure
to not reconfigure the internal register space and MBARs. Otherwise
the BootROM will not be able to continue after SPL jumps back to it.

To use this feature, please don't forget to change the BOOT_FROM line
in your board specfic kwbimage.cfg file this way:

    BOOT_FROM uart

Tested on these Marvell eval boards:
DB-MV784MP-GP - Armada XP
DB-88F6820-GP - Armada 38x

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Dirk Eibach <eibach@gdsys.de>
Cc: Kevin Smith <kevin.smith@elecsyscorp.com>
Cc: Luka Perkov <luka.perkov@sartura.hr>

diff --git a/Makefile b/Makefile
index fd06024104288ca3f2db95fa377966205ccc34ee..3b2eebf4b72cc343dda7bb50e45e8000f4693a28 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -901,7 +901,7 @@ MKIMAGEFLAGS_u-boot.kwb = -n $(srctree)/$(CONFIG_SYS_KWD_CONFIG:"%"=%) \
        -T kwbimage -a $(CONFIG_SYS_TEXT_BASE) -e $(CONFIG_SYS_TEXT_BASE)
 
 MKIMAGEFLAGS_u-boot-spl.kwb = -n $(srctree)/$(CONFIG_SYS_KWD_CONFIG:"%"=%) \
-       -T kwbimage -a $(CONFIG_SPL_TEXT_BASE) -e $(CONFIG_SPL_TEXT_BASE)
+       -T kwbimage -a $(CONFIG_SYS_TEXT_BASE) -e $(CONFIG_SYS_TEXT_BASE)
 
 MKIMAGEFLAGS_u-boot.pbl = -n $(srctree)/$(CONFIG_SYS_FSL_PBL_RCW:"%"=%) \
                -R $(srctree)/$(CONFIG_SYS_FSL_PBL_PBI:"%"=%) -T pblimage
@@ -909,8 +909,18 @@ MKIMAGEFLAGS_u-boot.pbl = -n $(srctree)/$(CONFIG_SYS_FSL_PBL_RCW:"%"=%) \
 u-boot.img u-boot.kwb u-boot.pbl: u-boot.bin FORCE
        $(call if_changed,mkimage)
 
+# If the kwboot xmodem protocol is used, to boot U-Boot on the MVEBU
+# SoC's, the SPL U-Boot returns to the BootROM after it completes
+# the SDRAM setup. The BootROM expects no U-Boot header in the main
+# U-Boot image. So we need to combine SPL and u-boot.bin instead of
+# u-boot.img in this case.
+ifdef CONFIG_MVEBU_BOOTROM_UARTBOOT
+u-boot-spl.kwb: u-boot.bin spl/u-boot-spl.bin FORCE
+       $(call if_changed,mkimage)
+else
 u-boot-spl.kwb: u-boot.img spl/u-boot-spl.bin FORCE
        $(call if_changed,mkimage)
+endif
 
 MKIMAGEFLAGS_u-boot-dtb.img = $(MKIMAGEFLAGS_u-boot.img)
 

diff --git a/arch/arm/mach-mvebu/Kconfig b/arch/arm/mach-mvebu/Kconfig
index 1aa964091ab365c76f18f19492f978ed9256c274..79ff0e82786db029a267458e125bbf9c11d26ec9 100644 (file)
--- a/arch/arm/mach-mvebu/Kconfig
+++ b/arch/arm/mach-mvebu/Kconfig
@@ -18,4 +18,14 @@ endchoice
 config SYS_SOC
        default "mvebu"
 
+config MVEBU_BOOTROM_UARTBOOT
+       bool "Use kwboot to boot via BootROM xmodem protocol"
+       help
+         This option provides support for booting via the Marvell
+         xmodem protocol, used by the kwboot tool.
+
+         Please don't forget to configure the boot device in
+         the board specific kwbimage.cfg file this way:
+             BOOT_FROM uart
+
 endif

diff --git a/arch/arm/mach-mvebu/include/mach/cpu.h b/arch/arm/mach-mvebu/include/mach/cpu.h
index 6fa41736e2aa140c354bd61bc9d3fc6a03e33bd7..5e8bf0c4ce0311704201ca942ee67b9d8514df41 100644 (file)
--- a/arch/arm/mach-mvebu/include/mach/cpu.h
+++ b/arch/arm/mach-mvebu/include/mach/cpu.h
@@ -119,6 +119,8 @@ int mvebu_mbus_probe(struct mbus_win windows[], int count);
 int mvebu_soc_family(void);
 u32 mvebu_get_nand_clock(void);
 
+void return_to_bootrom(void);
+
 int mv_sdh_init(unsigned long regbase, u32 max_clk, u32 min_clk, u32 quirks);
 
 /*

diff --git a/arch/arm/mach-mvebu/include/mach/soc.h b/arch/arm/mach-mvebu/include/mach/soc.h
index 02c21bcdeddde02389003048975b97e268804f52..22abde080e13fc1e8db0dd9c5fa3f04edf5835a0 100644 (file)
--- a/arch/arm/mach-mvebu/include/mach/soc.h
+++ b/arch/arm/mach-mvebu/include/mach/soc.h
@@ -31,7 +31,7 @@
 /* SOC specific definations */
 #define INTREG_BASE            0xd0000000
 #define INTREG_BASE_ADDR_REG   (INTREG_BASE + 0x20080)
-#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SYS_MVEBU_DDR_A38X)
+#if defined(CONFIG_SPL_BUILD)
 /*
  * On A38x switching the regs base address without running from
  * SDRAM doesn't seem to work. So let the SPL still use the

diff --git a/arch/arm/mach-mvebu/lowlevel_spl.S b/arch/arm/mach-mvebu/lowlevel_spl.S
index 69da7fe7afd6ced7a689032ed3ce5ccd32f1cbf5..2e2181ecea5ebc2ad656772ff6056b9f43b42a6b 100644 (file)
--- a/arch/arm/mach-mvebu/lowlevel_spl.S
+++ b/arch/arm/mach-mvebu/lowlevel_spl.S
@@ -5,10 +5,26 @@
 #include <config.h>
 #include <linux/linkage.h>
 
+#ifdef CONFIG_MVEBU_BOOTROM_UARTBOOT
 ENTRY(save_boot_params)
+       stmfd   sp!, {r0 - r12, lr}     /* @ save registers on stack */
+       ldr     r12, =CONFIG_SPL_BOOTROM_SAVE
+       str     sp, [r12]
        b       save_boot_params_ret
 ENDPROC(save_boot_params)
 
+ENTRY(return_to_bootrom)
+       ldr     r12, =CONFIG_SPL_BOOTROM_SAVE
+       ldr     sp, [r12]
+       mov     r0, #0x0                /* @ return value: 0x0 NO_ERR */
+       ldmfd   sp!, {r0 - r12, pc}     /* @ restore regs and return */
+ENDPROC(return_to_bootrom)
+#else
+ENTRY(save_boot_params)
+       b       save_boot_params_ret
+ENDPROC(save_boot_params)
+#endif
+
 /*
  * cache_inv - invalidate Cache line
  * r0 - dest

diff --git a/arch/arm/mach-mvebu/spl.c b/arch/arm/mach-mvebu/spl.c
index af61ded42efe070ffe6d3102748a69c2735f57d7..26ff1a24ac103458307014ddea30ac41b9b87e3c 100644 (file)
--- a/arch/arm/mach-mvebu/spl.c
+++ b/arch/arm/mach-mvebu/spl.c
@@ -34,8 +34,18 @@ void board_init_f(ulong dummy)
        /* Set global data pointer */
        gd = &gdata;
 
+#ifndef CONFIG_MVEBU_BOOTROM_UARTBOOT
+       /*
+        * Only call arch_cpu_init() when not returning to the
+        * Marvell BootROM, which is done when booting via
+        * the xmodem protocol (kwboot tool). Otherwise the
+        * internal register will get remapped and the BootROM
+        * can't continue to run correctly.
+        */
+
        /* Linux expects the internal registers to be at 0xf1000000 */
        arch_cpu_init();
+#endif
 
        /*
         * Pin muxing needs to be done before UART output, since
@@ -54,5 +64,20 @@ void board_init_f(ulong dummy)
        /* Setup DDR */
        ddr3_init();
 
+#ifdef CONFIG_MVEBU_BOOTROM_UARTBOOT
+       /*
+        * Return to the BootROM to continue the Marvell xmodem
+        * UART boot protocol. As initiated by the kwboot tool.
+        *
+        * This can only be done by the BootROM and not by the
+        * U-Boot SPL infrastructure, since the beginning of the
+        * image is already read and interpreted by the BootROM.
+        * SPL has no chance to receive this information. So we
+        * need to return to the BootROM to enable this xmodem
+        * UART download.
+        */
+       return_to_bootrom();
+#endif
+
        board_init_r(NULL, 0);
 }