[RFC, PATCH] i.MX: Add provisions to boot from IRAM

[Andrey Smirnov <andrew.smirnov@gmail.com>]

This commit add a very basic code to allow Barebox to be booted from
IRAM. Given that the amount of IRAM on most i.MX variants is
insufficient to contain a copy of Barebox with any reasonable degree
of functionality this code uses IRAM only as a temporary location and
eventually bootstraps from DRAM. But the presense of the intermediate
IRAM-only stage allows to add provisions to test the area of DRAM that
Barebox would be using to facilitate various testing scenarious.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
 arch/arm/boards/freescale-mx51-babbage/Makefile    |  3 ++
 .../flash-header-imx51-babbage-xload.imxcfg        | 59 ++++++++++++++++++++++
 arch/arm/boards/freescale-mx51-babbage/lowlevel.c  | 25 +++++++++
 arch/arm/configs/imx_v7-xload_defconfig            | 46 +++++++++++++++++
 arch/arm/mach-imx/Kconfig                          | 15 ++++++
 arch/arm/mach-imx/Makefile                         |  1 +
 arch/arm/mach-imx/xload.c                          | 54 ++++++++++++++++++++
 images/Makefile.imx                                | 20 +++++++-
 8 files changed, 222 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm/boards/freescale-mx51-babbage/flash-header-imx51-babbage-xload.imxcfg
 create mode 100644 arch/arm/configs/imx_v7-xload_defconfig
 create mode 100644 arch/arm/mach-imx/xload.c

diff --git a/arch/arm/boards/freescale-mx51-babbage/Makefile b/arch/arm/boards/freescale-mx51-babbage/Makefile
index 6252c88..31b8fcd 100644
--- a/arch/arm/boards/freescale-mx51-babbage/Makefile
+++ b/arch/arm/boards/freescale-mx51-babbage/Makefile
@@ -1,3 +1,6 @@
 obj-y += board.o flash-header-imx51-babbage.dcd.o
 extra-y += flash-header-imx51-babbage.dcd.S flash-header-imx51-babbage.dcd
 lwl-y += lowlevel.o
+
+obj-$(CONFIG_ARCH_IMX_XLOAD) += flash-header-imx51-babbage-xload.dcd.o
+extra-$(CONFIG_ARCH_IMX_XLOAD) += flash-header-imx51-babbage-xload.dcd.S flash-header-imx51-babbage-xload.dcd
diff --git a/arch/arm/boards/freescale-mx51-babbage/flash-header-imx51-babbage-xload.imxcfg b/arch/arm/boards/freescale-mx51-babbage/flash-header-imx51-babbage-xload.imxcfg
new file mode 100644
index 0000000..a04ac75
--- /dev/null
+++ b/arch/arm/boards/freescale-mx51-babbage/flash-header-imx51-babbage-xload.imxcfg
@@ -0,0 +1,59 @@
+loadaddr CONFIG_ARCH_IMX_UNUSED_IRAM_BASE
+soc imx51
+dcdofs 0x400
+wm 32 0x73fa88a0 0x00000200
+wm 32 0x73fa850c 0x000020c5
+wm 32 0x73fa8510 0x000020c5
+wm 32 0x73fa883c 0x00000002
+wm 32 0x73fa8848 0x00000002
+wm 32 0x73fa84b8 0x000000e7
+wm 32 0x73fa84bc 0x00000045
+wm 32 0x73fa84c0 0x00000045
+wm 32 0x73fa84c4 0x00000045
+wm 32 0x73fa84c8 0x00000045
+wm 32 0x73fa8820 0x00000000
+wm 32 0x73fa84a4 0x00000003
+wm 32 0x73fa84a8 0x00000003
+wm 32 0x73fa84ac 0x000000e3
+wm 32 0x73fa84b0 0x000000e3
+wm 32 0x73fa84b4 0x000000e3
+wm 32 0x73fa84cc 0x000000e3
+wm 32 0x73fa84d0 0x000000e2
+wm 32 0x73fa882c 0x00000004
+wm 32 0x73fa88a4 0x00000004
+wm 32 0x73fa88ac 0x00000004
+wm 32 0x73fa88b8 0x00000004
+wm 32 0x83fd9000 0x82a20000
+wm 32 0x83fd9008 0x82a20000
+wm 32 0x83fd9010 0x000ad0d0
+wm 32 0x83fd9004 0x3f3584ab
+wm 32 0x83fd900c 0x3f3584ab
+wm 32 0x83fd9014 0x04008008
+wm 32 0x83fd9014 0x0000801a
+wm 32 0x83fd9014 0x0000801b
+wm 32 0x83fd9014 0x00448019
+wm 32 0x83fd9014 0x07328018
+wm 32 0x83fd9014 0x04008008
+wm 32 0x83fd9014 0x00008010
+wm 32 0x83fd9014 0x00008010
+wm 32 0x83fd9014 0x06328018
+wm 32 0x83fd9014 0x03808019
+wm 32 0x83fd9014 0x00408019
+wm 32 0x83fd9014 0x00008000
+wm 32 0x83fd9014 0x0400800c
+wm 32 0x83fd9014 0x0000801e
+wm 32 0x83fd9014 0x0000801f
+wm 32 0x83fd9014 0x0000801d
+wm 32 0x83fd9014 0x0732801c
+wm 32 0x83fd9014 0x0400800c
+wm 32 0x83fd9014 0x00008014
+wm 32 0x83fd9014 0x00008014
+wm 32 0x83fd9014 0x0632801c
+wm 32 0x83fd9014 0x0380801d
+wm 32 0x83fd9014 0x0040801d
+wm 32 0x83fd9014 0x00008004
+wm 32 0x83fd9000 0xb2a20000
+wm 32 0x83fd9008 0xb2a20000
+wm 32 0x83fd9010 0x000ad6d0
+wm 32 0x83fd9034 0x90000000
+wm 32 0x83fd9014 0x00000000
diff --git a/arch/arm/boards/freescale-mx51-babbage/lowlevel.c b/arch/arm/boards/freescale-mx51-babbage/lowlevel.c
index 3bb8614..e308553 100644
--- a/arch/arm/boards/freescale-mx51-babbage/lowlevel.c
+++ b/arch/arm/boards/freescale-mx51-babbage/lowlevel.c
@@ -3,6 +3,7 @@
 #include <common.h>
 #include <mach/esdctl.h>
 #include <mach/generic.h>
+#include <asm/cache.h>
 #include <asm/barebox-arm-head.h>
 #include <asm/barebox-arm.h>

@@ -53,3 +54,27 @@ ENTRY_FUNCTION(start_imx51_babbage, r0, r1, r2)

 	imx51_barebox_entry(fdt);
 }
+
+static noinline void babbage_entry(void)
+{
+	arm_early_mmu_cache_invalidate();
+
+	relocate_to_current_adr();
+	setup_c();
+
+	puts_ll("lowlevel init done\n");
+
+	imx51_barebox_entry(NULL);
+}
+
+ENTRY_FUNCTION(start_imx51_babbage_xload, r0, r1, r2)
+{
+	imx5_cpu_lowlevel_init();
+
+	if (IS_ENABLED(CONFIG_DEBUG_LL))
+		setup_uart();
+
+	arm_setup_stack(0x20000000 - 16);
+
+	babbage_entry();
+}
diff --git a/arch/arm/configs/imx_v7-xload_defconfig b/arch/arm/configs/imx_v7-xload_defconfig
new file mode 100644
index 0000000..41293fb
--- /dev/null
+++ b/arch/arm/configs/imx_v7-xload_defconfig
@@ -0,0 +1,46 @@
+CONFIG_ARCH_IMX=y
+CONFIG_ARCH_IMX_IMXIMAGE=y
+CONFIG_ARCH_IMX_XLOAD=y
+
+CONFIG_ARCH_IMX51=y
+CONFIG_IMX_MULTI_BOARDS=y
+CONFIG_MACH_FREESCALE_MX51_PDK=y
+
+CONFIG_THUMB2_BAREBOX=y
+# CONFIG_CMD_ARM_CPUINFO is not set
+CONFIG_ARM_OPTIMZED_STRING_FUNCTIONS=y
+CONFIG_MMU=y
+CONFIG_TEXT_BASE=0x0
+CONFIG_MALLOC_SIZE=0x0
+CONFIG_MALLOC_DUMMY=y
+CONFIG_RELOCATABLE=y
+CONFIG_BAUDRATE=115200
+CONFIG_SHELL_NONE=y
+
+CONFIG_DEBUG_LL=y
+CONFIG_DEBUG_IMX51_UART=y
+CONFIG_DEBUG_IMX_UART_PORT=1
+
+CONFIG_HAS_DEBUG_LL=y
+# CONFIG_ERRNO_MESSAGES is not set
+# CONFIG_TIMESTAMP is not set
+# CONFIG_DEFAULT_ENVIRONMENT is not set
+CONFIG_DRIVER_SERIAL_IMX=y
+
+CONFIG_MCI=y
+CONFIG_MCI_STARTUP=y
+# CONFIG_MCI_WRITE is not set
+
+CONFIG_MCI_IMX_ESDHC=y
+
+CONFIG_EEPROM_AT25=y
+
+CONFIG_WATCHDOG_IMX_RESET_SOURCE=y
+CONFIG_WATCHDOG=y
+CONFIG_WATCHDOG_IMX=y
+
+# CONFIG_FS_RAMFS is not set
+# CONFIG_FS_DEVFS is not set
+CONFIG_FS_FAT=y
+CONFIG_BOOTSTRAP=y
+CONFIG_BOOTSTRAP_DISK=y
diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index c713477..3ccd060 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -68,6 +68,21 @@ config ARCH_IMX_IMXIMAGE
 	help
 	  if enabled the imx-image tool is compiled

+config ARCH_IMX_XLOAD
+	bool
+	depends on ARCH_IMX51
+	prompt "Build preloader image"
+
+config ARCH_IMX_UNUSED_IRAM_BASE
+       hex
+       depends on ARCH_IMX_XLOAD
+       default 0x1ffe2000 if ARCH_IMX51
+
+config ARCH_IMX_UNUSED_IRAM_SIZE
+       hex
+       depends on ARCH_IMX_XLOAD
+       default 0x16000 if ARCH_IMX51
+
 choice
 	depends on ARCH_IMX_INTERNAL_BOOT
 	prompt "Internal boot source"
diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile
index ae953b1..0320d1c 100644
--- a/arch/arm/mach-imx/Makefile
+++ b/arch/arm/mach-imx/Makefile
@@ -12,6 +12,7 @@ pbl-$(CONFIG_ARCH_IMX53) += imx53.o imx5.o esdctl-v4.o
 obj-$(CONFIG_ARCH_IMX6) += imx6.o usb-imx6.o clk-imx6.o
 lwl-$(CONFIG_ARCH_IMX6) += imx6-mmdc.o
 obj-$(CONFIG_ARCH_IMX6SX) += clk-imx6sx.o
+obj-$(CONFIG_ARCH_IMX_XLOAD) += xload.o
 obj-$(CONFIG_IMX_IIM)	+= iim.o
 obj-$(CONFIG_IMX_OCOTP)	+= ocotp.o
 obj-$(CONFIG_NAND_IMX) += nand.o
diff --git a/arch/arm/mach-imx/xload.c b/arch/arm/mach-imx/xload.c
new file mode 100644
index 0000000..07d6520
--- /dev/null
+++ b/arch/arm/mach-imx/xload.c
@@ -0,0 +1,54 @@
+#include <bootsource.h>
+#include <bootstrap.h>
+#include <common.h>
+#include <malloc.h>
+#include <init.h>
+#include <envfs.h>
+#include <linux/sizes.h>
+#include <fs.h>
+#include <io.h>
+
+#include <linux/clkdev.h>
+#include <linux/stat.h>
+#include <linux/clk.h>
+
+#include <mach/devices-imx51.h>
+
+static __noreturn int imx_xload(void)
+{
+	enum bootsource bootsource = bootsource_get();
+	void *buf;
+
+	switch (bootsource) {
+	case BOOTSOURCE_MMC:
+		buf = bootstrap_read_disk("disk0.0", "fat");
+		break;
+	default:
+		pr_err("unknown bootsource %d\n", bootsource);
+		hang();
+	}
+
+	if (!buf) {
+		pr_err("failed to load barebox.bin\n");
+		hang();
+	}
+
+	pr_info("starting bootloader...\n");
+
+	bootstrap_boot(buf, 0);
+
+	hang();
+}
+
+static int imx_devices_init(void)
+{
+#ifdef CONFIG_MCI_IMX_ESDHC
+	imx51_add_mmc0(NULL);
+	imx51_add_mmc1(NULL);
+#endif
+
+	barebox_main = imx_xload;
+
+	return 0;
+}
+coredevice_initcall(imx_devices_init);
diff --git a/images/Makefile.imx b/images/Makefile.imx
index 415b294..6b44958 100644
--- a/images/Makefile.imx
+++ b/images/Makefile.imx
@@ -4,8 +4,15 @@

 # %.imximg - convert into i.MX image
 # ----------------------------------------------------------------
+
+ifdef CONFIG_ARCH_IMX_XLOAD
+$(obj)/%.imximg: $(obj)/% FORCE
+	$(call cmd,check_file_size,$<,$(CONFIG_ARCH_IMX_UNUSED_IRAM_SIZE))
+	$(call if_changed,imx_image)
+else
 $(obj)/%.imximg: $(obj)/% FORCE
 	$(call if_changed,imx_image)
+endif

 # ----------------------- i.MX25 based boards ---------------------------
 pblx-$(CONFIG_MACH_TX25) += start_imx25_karo_tx25
@@ -29,7 +36,18 @@ image-$(CONFIG_MACH_PCM038) += barebox-phytec-phycore-imx27.img
 pblx-$(CONFIG_MACH_FREESCALE_MX51_PDK) += start_imx51_babbage
 CFG_start_imx51_babbage.pblx.imximg = $(board)/freescale-mx51-babbage/flash-header-imx51-babbage.imxcfg
 FILE_barebox-freescale-imx51-babbage.img = start_imx51_babbage.pblx.imximg
-image-$(CONFIG_MACH_FREESCALE_MX51_PDK) += barebox-freescale-imx51-babbage.img
+imx-barebox-$(CONFIG_MACH_FREESCALE_MX51_PDK) += barebox-freescale-imx51-babbage.img
+
+pblx-$(CONFIG_MACH_FREESCALE_MX51_PDK) += start_imx51_babbage_xload
+CFG_start_imx51_babbage_xload.pblx.imximg = $(board)/freescale-mx51-babbage/flash-header-imx51-babbage-xload.imxcfg
+FILE_barebox-freescale-imx51-babbage-xload.img = start_imx51_babbage_xload.pblx.imximg
+imx-xload-$(CONFIG_MACH_FREESCALE_MX51_PDK) += barebox-freescale-imx51-babbage-xload.img
+
+ifdef CONFIG_ARCH_IMX_XLOAD
+image-y += $(imx-xload-y)
+else
+image-y += $(imx-barebox-y)
+endif

 pblx-$(CONFIG_MACH_EFIKA_MX_SMARTBOOK) += start_imx51_genesi_efikasb
 CFG_start_imx51_genesi_efikasb.pblx.imximg = $(board)/efika-mx-smartbook/flash-header-imx51-genesi-efikasb.imxcfg
--
2.1.4

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