The ST-Ericsson U8500 SoC has been used in mass-production for some Android smartphones released around 2012. In particular, Samsung has released more than 5 different smartphones based on U8500, e.g.
- Samsung Galaxy S III mini (GT-I8190) "golden" - Samsung Galaxy S Advance (GT-I9070) "janice" - Samsung Galaxy Xcover 2 (GT-S7710) "skomer"
and a few others.
Mainline Linux has great support for the Ux500 SoC, so these smartphones can also run Linux mainline quite well.
Unfortunately, the original Samsung bootloader used on these devices has limitations that prevent booting Linux mainline directly. It keeps the L2 cache enabled, which causes Linux to crash very early, shortly after decompressing the kernel.
Using U-Boot allows to circumvent these limitations. We can let the Samsung bootloader chain-load U-Boot and U-Boot locks the L2 cache before booting into Linux. U-Boot has several other advantages - it supports device-trees directly and we are no longer limited to flashing Android boot images through Samsung's proprietary download mode.
The Samsung "stemmy" board covers all Samsung devices based on U8500. Add minimal support for "stemmy". For now only UART is supported but this will be extended later.
Signed-off-by: Stephan Gerhold stephan@gerhold.net ---
arch/arm/dts/Makefile | 2 + arch/arm/dts/ste-ux500-samsung-stemmy.dts | 20 +++++++++ arch/arm/mach-u8500/Kconfig | 21 ++++++++++ board/ste/stemmy/Kconfig | 12 ++++++ board/ste/stemmy/MAINTAINERS | 6 +++ board/ste/stemmy/Makefile | 2 + board/ste/stemmy/README | 49 +++++++++++++++++++++++ board/ste/stemmy/stemmy.c | 18 +++++++++ configs/stemmy_defconfig | 18 +++++++++ include/configs/stemmy.h | 29 ++++++++++++++ 10 files changed, 177 insertions(+) create mode 100644 arch/arm/dts/ste-ux500-samsung-stemmy.dts create mode 100644 board/ste/stemmy/Kconfig create mode 100644 board/ste/stemmy/MAINTAINERS create mode 100644 board/ste/stemmy/Makefile create mode 100644 board/ste/stemmy/README create mode 100644 board/ste/stemmy/stemmy.c create mode 100644 configs/stemmy_defconfig create mode 100644 include/configs/stemmy.h
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile index 0127a91a82..83aea3aa54 100644 --- a/arch/arm/dts/Makefile +++ b/arch/arm/dts/Makefile @@ -384,6 +384,8 @@ dtb-$(CONFIG_FSL_LSCH2) += fsl-ls1043a-qds-duart.dtb \ dtb-$(CONFIG_TARGET_DRAGONBOARD410C) += dragonboard410c.dtb dtb-$(CONFIG_TARGET_DRAGONBOARD820C) += dragonboard820c.dtb
+dtb-$(CONFIG_TARGET_STEMMY) += ste-ux500-samsung-stemmy.dtb + dtb-$(CONFIG_STM32F4) += stm32f429-disco.dtb \ stm32429i-eval.dtb \ stm32f469-disco.dtb diff --git a/arch/arm/dts/ste-ux500-samsung-stemmy.dts b/arch/arm/dts/ste-ux500-samsung-stemmy.dts new file mode 100644 index 0000000000..7e7f4c823a --- /dev/null +++ b/arch/arm/dts/ste-ux500-samsung-stemmy.dts @@ -0,0 +1,20 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/dts-v1/; + +#include "ste-dbx5x0-u-boot.dtsi" +#include "ste-ab8500.dtsi" + +/ { + compatible = "samsung,stemmy", "st-ericsson,u8500"; + + chosen { + stdout-path = &serial2; + }; + + soc { + /* Debugging console UART */ + uart@80007000 { + status = "okay"; + }; + }; +}; diff --git a/arch/arm/mach-u8500/Kconfig b/arch/arm/mach-u8500/Kconfig index 3bc76295cb..7478deb25f 100644 --- a/arch/arm/mach-u8500/Kconfig +++ b/arch/arm/mach-u8500/Kconfig @@ -3,4 +3,25 @@ if ARCH_U8500 config SYS_SOC default "u8500"
+choice + prompt "U8500 board selection" + +config TARGET_STEMMY + bool "Samsung (stemmy) board" + help + The Samsung "stemmy" board supports Samsung smartphones released with + the ST-Ericsson NovaThor U8500 SoC, e.g. + + - Samsung Galaxy S III mini (GT-I8190) "golden" + - Samsung Galaxy S Advance (GT-I9070) "janice" + - Samsung Galaxy Xcover 2 (GT-S7710) "skomer" + + and likely others as well (untested). + + See board/ste/stemmy/README for details. + +endchoice + +source "board/ste/stemmy/Kconfig" + endif diff --git a/board/ste/stemmy/Kconfig b/board/ste/stemmy/Kconfig new file mode 100644 index 0000000000..b890ba51cb --- /dev/null +++ b/board/ste/stemmy/Kconfig @@ -0,0 +1,12 @@ +if TARGET_STEMMY + +config SYS_BOARD + default "stemmy" + +config SYS_VENDOR + default "ste" + +config SYS_CONFIG_NAME + default "stemmy" + +endif diff --git a/board/ste/stemmy/MAINTAINERS b/board/ste/stemmy/MAINTAINERS new file mode 100644 index 0000000000..37daabea9c --- /dev/null +++ b/board/ste/stemmy/MAINTAINERS @@ -0,0 +1,6 @@ +STEMMY BOARD +M: Stephan Gerhold stephan@gerhold.net +S: Maintained +F: board/ste/stemmy/ +F: include/configs/stemmy.h +F: configs/stemmy_defconfig diff --git a/board/ste/stemmy/Makefile b/board/ste/stemmy/Makefile new file mode 100644 index 0000000000..1245099bc9 --- /dev/null +++ b/board/ste/stemmy/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-or-later +obj-y := stemmy.o diff --git a/board/ste/stemmy/README b/board/ste/stemmy/README new file mode 100644 index 0000000000..81f72426f2 --- /dev/null +++ b/board/ste/stemmy/README @@ -0,0 +1,49 @@ +ST-Ericsson U8500 Samsung "stemmy" board +======================================== + +The "stemmy" board supports Samsung smartphones released with +the ST-Ericsson NovaThor U8500 SoC, e.g. + + - Samsung Galaxy S III mini (GT-I8190) "golden" + - Samsung Galaxy S Advance (GT-I9070) "janice" + - Samsung Galaxy Xcover 2 (GT-S7710) "skomer" + +and likely others as well (untested). + +At the moment, U-Boot is intended to be chain-loaded from +the original Samsung bootloader, not replacing it entirely. + +Installation +------------ + +1. Setup cross compiler, e.g. export CROSS_COMPILE=arm-none-eabi- +2. make stemmy_defconfig +3. make + +For newer devices (golden and skomer), the U-Boot binary has to be packed into +an Android boot image. janice boots the raw U-Boot binary from the boot partition. + +4. Obtain mkbootimg, e.g. https://android.googlesource.com/platform/system/core/+/refs/tags/android-7.... +5. mkbootimg \ + --kernel=u-boot.bin \ + --base=0x00000000 \ + --kernel_offset=0x00100000 \ + --ramdisk_offset=0x02000000 \ + --tags_offset=0x00000100 \ + --output=u-boot.img + +6. Enter Samsung download mode (press Power + Home + Volume Down) +7. Flash U-Boot image to Android boot partition using Heimdall: + https://gitlab.com/BenjaminDobell/Heimdall + + heimdall flash --Kernel u-boot.(bin|img) + +8. After reboot U-Boot prompt should appear via UART. + +UART +---- + +UART is available through the micro USB port, similar to the Carkit standard. +With a ~619kOhm resistor between ID and GND, 1.8V RX/TX is available at D+/D-. + +Make sure to connect the UART cable *before* turning on the phone. diff --git a/board/ste/stemmy/stemmy.c b/board/ste/stemmy/stemmy.c new file mode 100644 index 0000000000..8cf6f18755 --- /dev/null +++ b/board/ste/stemmy/stemmy.c @@ -0,0 +1,18 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2019 Stephan Gerhold stephan@gerhold.net + */ +#include <common.h> + +DECLARE_GLOBAL_DATA_PTR; + +int dram_init(void) +{ + gd->ram_size = get_ram_size(CONFIG_SYS_SDRAM_BASE, CONFIG_SYS_SDRAM_SIZE); + return 0; +} + +int board_init(void) +{ + return 0; +} diff --git a/configs/stemmy_defconfig b/configs/stemmy_defconfig new file mode 100644 index 0000000000..6908ef3448 --- /dev/null +++ b/configs/stemmy_defconfig @@ -0,0 +1,18 @@ +CONFIG_ARM=y +CONFIG_ARCH_U8500=y +CONFIG_SYS_TEXT_BASE=0x100000 +CONFIG_NR_DRAM_BANKS=1 +CONFIG_SYS_CONSOLE_INFO_QUIET=y +CONFIG_HUSH_PARSER=y +CONFIG_CMD_CONFIG=y +CONFIG_CMD_LICENSE=y +CONFIG_CMD_DM=y +CONFIG_CMD_GPIO=y +CONFIG_CMD_MMC=y +CONFIG_CMD_PART=y +CONFIG_CMD_GETTIME=y +CONFIG_EFI_PARTITION=y +CONFIG_DEFAULT_DEVICE_TREE="ste-ux500-samsung-stemmy" +# CONFIG_NET is not set +# CONFIG_MMC_HW_PARTITIONING is not set +# CONFIG_EFI_LOADER is not set diff --git a/include/configs/stemmy.h b/include/configs/stemmy.h new file mode 100644 index 0000000000..922eec43ee --- /dev/null +++ b/include/configs/stemmy.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2019 Stephan Gerhold stephan@gerhold.net + */ +#ifndef __CONFIGS_STEMMY_H +#define __CONFIGS_STEMMY_H + +#include <linux/sizes.h> + +#define CONFIG_SKIP_LOWLEVEL_INIT /* Loaded by another bootloader */ +#define CONFIG_SYS_MALLOC_LEN SZ_2M + +/* Physical Memory Map */ +#define PHYS_SDRAM_1 0x00000000 /* DDR-SDRAM Bank #1 */ +#define CONFIG_SYS_SDRAM_BASE PHYS_SDRAM_1 +#define CONFIG_SYS_SDRAM_SIZE SZ_1G +#define CONFIG_SYS_INIT_RAM_SIZE 0x00100000 +#define CONFIG_SYS_GBL_DATA_OFFSET (CONFIG_SYS_SDRAM_BASE + \ + CONFIG_SYS_INIT_RAM_SIZE - \ + GENERATED_GBL_DATA_SIZE) +#define CONFIG_SYS_INIT_SP_ADDR CONFIG_SYS_GBL_DATA_OFFSET + +/* FIXME: This should be loaded from device tree... */ +#define CONFIG_SYS_L2_PL310 +#define CONFIG_SYS_PL310_BASE 0xa0412000 + +#define CONFIG_SYS_LOAD_ADDR 0x00100000 + +#endif