diff mbox series

[RFC,5/5] board: Add new Samsung "stemmy" board based on ST-Ericsson U8500

Message ID 20200104174519.19238-6-stephan@gerhold.net
State Accepted
Commit 43d28855d8ed7929856e376524eb41a74731aed1
Headers show
Series arm: Restore minimal support for ST-Ericsson U8500 SoC | expand

Commit Message

Stephan Gerhold Jan. 4, 2020, 5:45 p.m. UTC 
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 at 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

Comments

Linus Walleij Jan. 6, 2020, 1:50 a.m. UTC | #1 
On Sat, Jan 4, 2020 at 6:48 PM Stephan Gerhold <stephan at gerhold.net> wrote:

> 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 at gerhold.net>

Reviewed-by: Linus Walleij <linus.walleij at linaro.org>

Yours,
Linus Walleij
Tom Rini Jan. 23, 2020, 9:58 p.m. UTC | #2 
On Sat, Jan 04, 2020 at 06:45:19PM +0100, Stephan Gerhold wrote:

> 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 at gerhold.net>
> Reviewed-by: Linus Walleij <linus.walleij at linaro.org>

Applied to u-boot/master, thanks!
diff mbox series

Patch

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 at 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 at 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-7.1.2_r37/mkbootimg/mkbootimg
+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 at 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 at 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