[PATCH] board: samsung: add support for Samsung Exynos mobile device boards

[PATCH] board: samsung: add support for Samsung Exynos mobile device boards

[Kaustabh Chakraborty]

Add support for a generic platform which intends to support multiple
boards powerid by Samsung Exynos SoCs. This patch also includes initial
support for three boards:
* Samsung Galaxy A2 Core
* Samsung Galaxy J6
* Samsung Galaxy J7 Prime

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
---
This patch has the following dependencies:
(NOTE: `x` indicates applied)

armv8-broken-cntfrq		- https://patch.msgid.link/20251017-armv8-broken-cntfrq-v2-1-1e043cbb657e@disroot.org
clk-exynos7870			- https://patch.msgid.link/20251017-clk-exynos7870-v1-0-83f90d425699@disroot.org
gpio-s5p-bank-fix		- https://patch.msgid.link/20251017-gpio-s5p-bank-fix-v1-1-41050462cea5@disroot.org
i2c-hs-exynos7			- https://patch.msgid.link/20251017-i2c-hs-exynos7-v1-1-ca080895d4b6@disroot.org
mmc-dw-exynos7870		- https://patch.msgid.link/20251017-mmc-dw-exynos7870-v1-0-a2c5139d9afe@disroot.org
phy-usb-exynos7870		- https://patch.msgid.link/20251017-phy-usb-exynos7870-v1-0-5885b00f0c87@disroot.org
pinctrl-exynos7870		- https://patch.msgid.link/20251017-pinctrl-exynos7870-v1-0-beaa92f95a0c@disroot.org
power-pmic-regulator-s2mpu05	- https://patch.msgid.link/20251017-power-pmic-regulator-s2mpu05-v1-0-91cadc0f4156@disroot.org
serial-s5p-exynos8895		- https://patch.msgid.link/20251017-serial-s5p-exynos8895-v1-1-b412dd112cfd@disroot.org
soc-pmu-exynos7			- https://patch.msgid.link/20251017-soc-pmu-exynos7-v1-1-553d18eaab0d@disroot.org
usb-dwc3-exynos7870		- https://patch.msgid.link/20251017-usb-dwc3-exynos7870-v1-0-fe46e2ed1908@disroot.org
---
 arch/arm/mach-exynos/Kconfig                       |  11 +-
 board/samsung/exynos-mobile/Kconfig                |  18 +
 board/samsung/exynos-mobile/MAINTAINERS            |   6 +
 board/samsung/exynos-mobile/Makefile               |   5 +
 .../samsung/exynos-mobile/debug-exynos7870.config  |   7 +
 board/samsung/exynos-mobile/exynos-mobile.c        | 372 +++++++++++++++++++++
 board/samsung/exynos-mobile/exynos-mobile.env      |  18 +
 configs/exynos-mobile_defconfig                    |  71 ++++
 doc/board/samsung/exynos-mobile.rst                | 112 +++++++
 doc/board/samsung/index.rst                        |   1 +
 include/configs/exynos-mobile.h                    |  14 +
 11 files changed, 634 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
index 2cd67d023867de29bf85fe6d68b3485dbb67853c..b084b7284aa08eafbc740e47fbc8385f8eb2d7db 100644
--- a/arch/arm/mach-exynos/Kconfig
+++ b/arch/arm/mach-exynos/Kconfig
@@ -2,7 +2,7 @@ if ARCH_EXYNOS
 
 config BOARD_COMMON
 	def_bool y
-	depends on !TARGET_SMDKV310 && !TARGET_ARNDALE && !TARGET_E850_96
+	depends on !TARGET_SMDKV310 && !TARGET_ARNDALE && !TARGET_EXYNOS_MOBILE && !TARGET_E850_96
 
 config SPI_BOOTING
 	bool
@@ -252,6 +252,14 @@ config TARGET_E850_96
 endchoice
 endif
 
+config TARGET_EXYNOS_MOBILE
+	bool "Samsung Exynos Generic Boards (for mobile devices)"
+	select ARM64
+	select BOARD_EARLY_INIT_F
+	select CLK_EXYNOS
+	select LINUX_KERNEL_IMAGE_HEADER
+	select OF_CONTROL
+
 config SYS_SOC
 	default "exynos"
 
@@ -277,5 +285,6 @@ source "board/samsung/smdk5420/Kconfig"
 source "board/samsung/espresso7420/Kconfig"
 source "board/samsung/axy17lte/Kconfig"
 source "board/samsung/e850-96/Kconfig"
+source "board/samsung/exynos-mobile/Kconfig"
 
 endif
diff --git a/board/samsung/exynos-mobile/Kconfig b/board/samsung/exynos-mobile/Kconfig
new file mode 100644
index 0000000000000000000000000000000000000000..ed7d16b8c6b718e1a0c2bcb24113b62135ec397c
--- /dev/null
+++ b/board/samsung/exynos-mobile/Kconfig
@@ -0,0 +1,18 @@
+if TARGET_EXYNOS_MOBILE
+
+config ENV_SOURCE_FILE
+	default "exynos-mobile"
+
+config LNX_KRNL_IMG_TEXT_OFFSET_BASE
+	default TEXT_BASE
+
+config SYS_BOARD
+	default "exynos-mobile"
+
+config SYS_CONFIG_NAME
+	default "exynos-mobile"
+
+config SYS_VENDOR
+	default "samsung"
+
+endif # TARGET_EXYNOS_MOBILE
diff --git a/board/samsung/exynos-mobile/MAINTAINERS b/board/samsung/exynos-mobile/MAINTAINERS
new file mode 100644
index 0000000000000000000000000000000000000000..11fea212fb15bb5714ad1de46aace231f0600b69
--- /dev/null
+++ b/board/samsung/exynos-mobile/MAINTAINERS
@@ -0,0 +1,6 @@
+Exynos Generic Boards (for mobile devices)
+M:	Kaustabh Chakraborty <kauschluss@disroot.org>
+S:	Maintained
+F:	board/samsung/exynos-mobile/
+F:	configs/exynos-mobile_defconfig
+F:	include/configs/exynos-mobile.h
diff --git a/board/samsung/exynos-mobile/Makefile b/board/samsung/exynos-mobile/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..e049ed217c18c7e2c173249608a8abc433299687
--- /dev/null
+++ b/board/samsung/exynos-mobile/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (C) 2025 Kaustabh Chakraborty <kauschluss@disroot.org>
+
+obj-y := exynos-mobile.o
diff --git a/board/samsung/exynos-mobile/debug-exynos7870.config b/board/samsung/exynos-mobile/debug-exynos7870.config
new file mode 100644
index 0000000000000000000000000000000000000000..1aa506a675d30b025651dd4575aee36de82b8d07
--- /dev/null
+++ b/board/samsung/exynos-mobile/debug-exynos7870.config
@@ -0,0 +1,7 @@
+CONFIG_DEBUG_UART=y
+CONFIG_DEBUG_UART_BASE=0x13820000
+CONFIG_DEBUG_UART_CLOCK=133250000
+CONFIG_DEBUG_UART_S5P=y
+CONFIG_LOG=y
+CONFIG_LOG_CONSOLE=y
+CONFIG_LOG_MAX_LEVEL=8
diff --git a/board/samsung/exynos-mobile/exynos-mobile.c b/board/samsung/exynos-mobile/exynos-mobile.c
new file mode 100644
index 0000000000000000000000000000000000000000..96316b1bfc90ae40c89585901b57318bfae9fe36
--- /dev/null
+++ b/board/samsung/exynos-mobile/exynos-mobile.c
@@ -0,0 +1,372 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Samsung Exynos Generic Board Source (for mobile devices)
+ *
+ * Copyright (c) 2025 Kaustabh Chakraborty <kauschluss@disroot.org>
+ */
+
+#include <asm/armv8/mmu.h>
+#include <blk.h>
+#include <bootflow.h>
+#include <ctype.h>
+#include <dm/ofnode.h>
+#include <env.h>
+#include <errno.h>
+#include <init.h>
+#include <limits.h>
+#include <linux/sizes.h>
+#include <lmb.h>
+#include <part.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define lmb_alloc(size, addr) \
+	lmb_alloc_mem(LMB_MEM_ALLOC_ANY, SZ_2M, addr, size, LMB_NONE)
+
+struct exynos_board_info {
+	const char *name;
+	const char *chip;
+	const u64 *dram_bank_bases;
+
+	const char *match_model;
+	const u8 match_max_rev;
+};
+
+/*
+ * The memory mapping includes all DRAM banks, along with the
+ * peripheral block, and a sentinel at the end. This is filled in
+ * dynamically.
+ */
+static struct mm_region exynos_mem_map[CONFIG_NR_DRAM_BANKS + 2] = {
+	{
+		/* Peripheral MMIO block */
+		.virt = 0x10000000UL,
+		.phys = 0x10000000UL,
+		.size = 0x10000000UL,
+		.attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRNE) |
+			 PTE_BLOCK_NON_SHARE | PTE_BLOCK_PXN | PTE_BLOCK_UXN,
+	},
+};
+
+struct mm_region *mem_map = exynos_mem_map;
+
+const u64 exynos7870_common_dram_bank_bases[CONFIG_NR_DRAM_BANKS] = {
+	0x40000000, 0x80000000, 0x100000000,
+};
+
+/*
+ * This array is used for matching the models and revisions with the
+ * devicetree used by U-Boot. This allows a single U-Boot to work on
+ * multiple devices.
+ *
+ * Entries are kept in lexicographical order of board SoCs, followed by
+ * board names.
+ */
+const struct exynos_board_info exynos_board_info_match[] = {
+	{
+		/* Samsung Galaxy A2 Core */
+		.name = "a2corelte",
+		.chip = "exynos7870",
+		.dram_bank_bases = exynos7870_common_dram_bank_bases,
+		.match_model = "A260",
+		.match_max_rev = U8_MAX,
+	}, {
+		/* Samsung Galaxy J6 */
+		.name = "j6lte",
+		.chip = "exynos7870",
+		.dram_bank_bases = exynos7870_common_dram_bank_bases,
+		.match_model = "J600",
+		.match_max_rev = U8_MAX,
+	}, {
+		/* Samsung Galaxy J7 Prime */
+		.name = "on7xelte",
+		.chip = "exynos7870",
+		.dram_bank_bases = exynos7870_common_dram_bank_bases,
+		.match_model = "G610",
+		.match_max_rev = U8_MAX,
+	},
+};
+
+static const char *exynos_prev_bl_get_bootargs(void)
+{
+	void *prev_bl_fdt_base = (void *)get_prev_bl_fdt_addr();
+	int chosen_node_offset, ret;
+	const struct fdt_property *bootargs_prop;
+
+	ret = fdt_path_offset(prev_bl_fdt_base, "/chosen");
+	chosen_node_offset = ret;
+	if (ret < 0) {
+		log_err("%s: /chosen node not found (FDT_ERR %d)\n", __func__,
+			ret);
+		return NULL;
+	}
+
+	bootargs_prop = fdt_get_property(prev_bl_fdt_base, chosen_node_offset,
+					 "bootargs", &ret);
+	if (!bootargs_prop) {
+		log_err("%s: /chosen/bootargs property not found (FDT_ERR %d)\n",
+			__func__, ret);
+		return NULL;
+	}
+
+	return bootargs_prop->data;
+}
+
+static void exynos_parse_dram_banks(const struct exynos_board_info *board_info,
+				    const void *fdt_base)
+{
+	u64 mem_addr, mem_size = 0;
+	u32 na, ns, i, j;
+	int offset;
+
+	/* #address-cells and #size-cells as defined in the fdt root. */
+	na = fdt_address_cells(fdt_base, 0);
+	ns = fdt_size_cells(fdt_base, 0);
+
+	fdt_for_each_subnode(offset, fdt_base, 0) {
+		if (strncmp(fdt_get_name(fdt_base, offset, NULL), "memory", 6))
+			continue;
+
+		for (i = 0; ; i++) {
+			mem_addr = fdtdec_get_addr_size_fixed(fdt_base, offset,
+							      "reg", i, na, ns,
+							      &mem_size, false);
+			if (mem_addr == FDT_ADDR_T_NONE)
+				break;
+
+			if (!mem_size)
+				continue;
+
+			for (j = 0; j < CONFIG_NR_DRAM_BANKS; j++) {
+				if (board_info->dram_bank_bases[j] != mem_addr)
+					continue;
+
+				mem_map[j + 1].phys = mem_addr;
+				mem_map[j + 1].virt = mem_addr;
+				mem_map[j + 1].size = mem_size;
+				mem_map[j + 1].attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) |
+						       PTE_BLOCK_INNER_SHARE;
+				break;
+			}
+		}
+	}
+}
+
+static int exynos_fastboot_setup(void)
+{
+	struct blk_desc *blk_dev;
+	struct disk_partition info = {0};
+	char buf[128];
+	phys_addr_t addr;
+	int offset, i, j;
+
+	/* Allocate and define buffer address for fastboot interface. */
+	if (lmb_alloc(CONFIG_FASTBOOT_BUF_SIZE, &addr)) {
+		log_err("%s: failed to allocate fastboot buffer\n", __func__);
+		return -ENOMEM;
+	}
+	env_set_hex("fastboot_addr_r", addr);
+
+	blk_dev = blk_get_dev("mmc", CONFIG_FASTBOOT_FLASH_MMC_DEV);
+	if (!blk_dev) {
+		log_err("%s: required mmc device not available\n", __func__);
+		return -ENODEV;
+	}
+
+	strcpy(buf, "fastboot_partition_alias_");
+	offset = strlen(buf);
+
+	for (i = 1; i < CONFIG_EFI_PARTITION_ENTRIES_NUMBERS; i++) {
+		if (part_get_info(blk_dev, i, &info))
+			continue;
+
+		/*
+		 * The partition name must be lowercase (stored in buf[]),
+		 * as is expected in all fastboot partitions ...
+		 */
+		strlcpy(buf + offset, info.name, sizeof(buf) - offset);
+		for (j = offset; buf[j]; j++)
+			buf[j] = tolower(buf[j]);
+		if (!strcmp(buf + offset, info.name))
+			continue;
+		/*
+		 * ... However, if that isn't the case, a fastboot
+		 * partition alias must be defined to establish it.
+		 */
+		env_set(buf, info.name);
+	}
+
+	return 0;
+}
+
+int board_fit_config_name_match(const char *name)
+{
+	const struct exynos_board_info *board_info;
+	const char *prev_bl_bootargs;
+	char buf[128];
+	int val, ret;
+	unsigned int i;
+
+	/*
+	 * Iterate over exynos_board_info_match[] to select the
+	 * appropriate board info struct. If not found, exit.
+	 */
+	for (i = 0; i < ARRAY_SIZE(exynos_board_info_match); i++) {
+		board_info = exynos_board_info_match + i;
+		snprintf(buf, sizeof(buf), "%s-%s", board_info->chip,
+			 board_info->name);
+
+		if (!strcmp(name, buf))
+			break;
+	}
+	if (i == ARRAY_SIZE(exynos_board_info_match))
+		return -1;
+
+	prev_bl_bootargs = exynos_prev_bl_get_bootargs();
+	if (!prev_bl_bootargs)
+		return -1;
+
+	/*
+	 * Read the cmdline property which stores the
+	 * bootloader/firmware version. An example value of the option
+	 * can be: "J600GDXU3ARH5". This can be used to verify the model
+	 * of the device.
+	 */
+	ret = cmdline_get_arg(prev_bl_bootargs, "androidboot.bootloader", &val);
+	if (ret < 0) {
+		log_err("%s: unable to find property for bootloader version (%d)\n",
+			__func__, ret);
+		return -1;
+	}
+
+	if (strncmp(prev_bl_bootargs + val, board_info->match_model,
+		    strlen(board_info->match_model)))
+		return -1;
+
+	/*
+	 * Read the cmdline property which stores the hardware revision.
+	 * This is required to allow selecting one of multiple dtbs
+	 * available of a single device, varying in hardware changes in
+	 * different revisions.
+	 */
+	ret = cmdline_get_arg(prev_bl_bootargs, "androidboot.revision", &val);
+	if (ret < 0)
+		ret = cmdline_get_arg(prev_bl_bootargs, "androidboot.hw_rev", &val);
+	if (ret < 0) {
+		log_err("%s: unable to find property for bootloader revision (%d)\n",
+			__func__, ret);
+		return -1;
+	}
+
+	if (strtoul(prev_bl_bootargs + val, NULL, 10) > board_info->match_max_rev)
+		return -1;
+
+	/*
+	 * Store the correct board info struct in gd->board_type to
+	 * allow other functions to access it.
+	 */
+	gd->board_type = (ulong)board_info;
+	log_debug("%s: device detected: %s\n", __func__, name);
+
+	return 0;
+}
+
+int timer_init(void)
+{
+	ofnode timer_node;
+
+	/*
+	 * In a lot of Exynos devices, the previous bootloader does not
+	 * set CNTFRQ_EL0 properly. However, the timer node in
+	 * devicetree has the correct frequency, use that instead.
+	 */
+	timer_node = ofnode_by_compatible(ofnode_null(), "arm,armv8-timer");
+	gd->arch.timer_rate_hz = ofnode_read_u32_default(timer_node,
+							 "clock-frequency", 0);
+
+	return 0;
+}
+
+int board_early_init_f(void)
+{
+	const struct exynos_board_info *board_info;
+
+	if (!gd->board_type)
+		return -ENODATA;
+	board_info = (const struct exynos_board_info *)gd->board_type;
+
+	exynos_parse_dram_banks(board_info, gd->fdt_blob);
+	/*
+	 * Some devices have multiple variants based on the amount of
+	 * memory and internal storage. The lowest bank base has been
+	 * observed to have the same memory range in all board variants.
+	 * For variants with more memory, the previous bootloader should
+	 * overlay the devicetree with the required extra memory ranges.
+	 */
+	exynos_parse_dram_banks(board_info, (const void *)get_prev_bl_fdt_addr());
+
+	return 0;
+}
+
+int dram_init(void)
+{
+	unsigned int i;
+
+	/* Select the largest RAM bank for U-Boot. */
+	for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
+		if (gd->ram_size < mem_map[i + 1].size) {
+			gd->ram_base = mem_map[i + 1].phys;
+			gd->ram_size = mem_map[i + 1].size;
+		}
+	}
+
+	return 0;
+}
+
+int dram_init_banksize(void)
+{
+	unsigned int i;
+
+	for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
+		gd->bd->bi_dram[i].start = mem_map[i + 1].phys;
+		gd->bd->bi_dram[i].size = mem_map[i + 1].size;
+	}
+
+	return 0;
+}
+
+int board_init(void)
+{
+	return 0;
+}
+
+int misc_init_r(void)
+{
+	const struct exynos_board_info *board_info;
+	const char *prev_bl_bootargs = exynos_prev_bl_get_bootargs();
+	char buf[128];
+	int val, ret;
+
+	if (!gd->board_type)
+		return -ENODATA;
+	board_info = (const struct exynos_board_info *)gd->board_type;
+
+	if (!prev_bl_bootargs)
+		return -ENODATA;
+
+	env_set("platform", board_info->chip);
+	env_set("board", board_info->name);
+
+	ret = cmdline_get_arg(prev_bl_bootargs, "androidboot.serialno", &val);
+	if (ret > 0) {
+		snprintf(buf, ret, "%s", prev_bl_bootargs + val);
+		env_set("serial#", buf);
+	}
+
+	/* EFI booting requires the path to correct dtb, specify it here. */
+	snprintf(buf, sizeof(buf), "exynos/%s-%s.dtb", board_info->chip,
+		 board_info->name);
+	env_set("fdtfile", buf);
+
+	return exynos_fastboot_setup();
+}
diff --git a/board/samsung/exynos-mobile/exynos-mobile.env b/board/samsung/exynos-mobile/exynos-mobile.env
new file mode 100644
index 0000000000000000000000000000000000000000..aa2e89afbacadcc86d0f1f5539f06bdb28bdc3b3
--- /dev/null
+++ b/board/samsung/exynos-mobile/exynos-mobile.env
@@ -0,0 +1,18 @@
+stdin=serial,button-kbd
+stdout=serial,vidconsole
+stderr=serial,vidconsole
+
+bootdelay=0
+bootcmd=bootefi bootmgr; pause; bootmenu
+
+fastbootcmd=echo "Fastboot Mode";
+	fastboot -l $fastboot_addr_r usb 0
+
+bootmenu_0=Continue Boot=boot
+bootmenu_1=Enter Fastboot Mode=run fastbootcmd
+bootmenu_2=UEFI Maintenance Menu=eficonfig
+bootmenu_3=Reboot=reset
+bootmenu_4=Power Off=poweroff
+
+button_cmd_0_name=Volume Down Key
+button_cmd_0=bootmenu
diff --git a/configs/exynos-mobile_defconfig b/configs/exynos-mobile_defconfig
new file mode 100644
index 0000000000000000000000000000000000000000..33fc2f2bf094017bba38579d47430ab68d5c6eaa
--- /dev/null
+++ b/configs/exynos-mobile_defconfig
@@ -0,0 +1,71 @@
+CONFIG_ARM=y
+CONFIG_SKIP_LOWLEVEL_INIT=y
+CONFIG_COUNTER_FREQUENCY=26000000
+CONFIG_POSITION_INDEPENDENT=y
+CONFIG_ARCH_EXYNOS=y
+CONFIG_SYS_MALLOC_LEN=0x2000000
+CONFIG_SYS_MALLOC_F_LEN=0x16000
+CONFIG_TARGET_EXYNOS_MOBILE=y
+CONFIG_NR_DRAM_BANKS=3
+CONFIG_DEFAULT_DEVICE_TREE="exynos/exynos7870-a2corelte"
+CONFIG_SYS_BOOTM_LEN=0x2000000
+CONFIG_SYS_LOAD_ADDR=0x80000000
+# CONFIG_PSCI_RESET is not set
+CONFIG_BUTTON_CMD=y
+CONFIG_SAVE_PREV_BL_FDT_ADDR=y
+CONFIG_SAVE_PREV_BL_INITRAMFS_START_ADDR=y
+CONFIG_SYS_PBSIZE=1024
+CONFIG_BOARD_TYPES=y
+# CONFIG_DISPLAY_CPUINFO is not set
+CONFIG_MISC_INIT_R=y
+CONFIG_HUSH_PARSER=y
+CONFIG_CMD_BOOTMENU=y
+CONFIG_CMD_POWEROFF=y
+CONFIG_CMD_FS_GENERIC=y
+CONFIG_EFI_PARTITION=y
+CONFIG_OF_UPSTREAM=y
+CONFIG_OF_LIST="exynos/exynos7870-a2corelte exynos/exynos7870-j6lte exynos/exynos7870-on7xelte"
+CONFIG_MULTI_DTB_FIT=y
+CONFIG_BUTTON=y
+CONFIG_BUTTON_REMAP_PHONE_KEYS=y
+CONFIG_CLK=y
+CONFIG_CLK_CCF=y
+CONFIG_CLK_EXYNOS7870=y
+CONFIG_USB_FUNCTION_FASTBOOT=y
+CONFIG_FASTBOOT_BUF_ADDR=0xdead0000
+CONFIG_FASTBOOT_FLASH=y
+CONFIG_FASTBOOT_FLASH_MMC_DEV=0
+CONFIG_SYS_I2C_S3C24X0=y
+CONFIG_BUTTON_KEYBOARD=y
+CONFIG_MISC=y
+CONFIG_MMC_BROKEN_CD=y
+CONFIG_MMC_IO_VOLTAGE=y
+CONFIG_MMC_UHS_SUPPORT=y
+CONFIG_MMC_HS400_SUPPORT=y
+CONFIG_MMC_DW=y
+CONFIG_PHY=y
+CONFIG_PHY_EXYNOS_USBDRD=y
+CONFIG_PINCTRL=y
+CONFIG_PINCTRL_EXYNOS78x0=y
+CONFIG_DM_PMIC=y
+CONFIG_PMIC_S2MPS11=y
+CONFIG_DM_REGULATOR=y
+CONFIG_DM_REGULATOR_FIXED=y
+CONFIG_DM_REGULATOR_S2MPS11=y
+CONFIG_SOC_SAMSUNG=y
+CONFIG_EXYNOS_PMU=y
+CONFIG_SYSRESET=y
+CONFIG_SYSRESET_CMD_POWEROFF=y
+CONFIG_SYSRESET_SYSCON=y
+CONFIG_USB=y
+CONFIG_DM_USB_GADGET=y
+CONFIG_USB_DWC3=y
+CONFIG_USB_DWC3_GENERIC=y
+CONFIG_USB_GADGET=y
+CONFIG_USB_GADGET_MANUFACTURER="Samsung"
+CONFIG_USB_GADGET_VENDOR_NUM=0x04e8
+CONFIG_USB_GADGET_PRODUCT_NUM=0x6602
+CONFIG_VIDEO=y
+CONFIG_VIDEO_SIMPLE=y
+CONFIG_FS_EXT4=y
+CONFIG_FS_FAT=y
diff --git a/doc/board/samsung/exynos-mobile.rst b/doc/board/samsung/exynos-mobile.rst
new file mode 100644
index 0000000000000000000000000000000000000000..6390c66ffc38a41f01cb51c7406397cfc5a3d223
--- /dev/null
+++ b/doc/board/samsung/exynos-mobile.rst
@@ -0,0 +1,112 @@
+.. SPDX-License-Identifier: GPL-2.0+
+.. sectionauthor:: Kaustabh Chakraborty <kauschluss@disroot.org>
+
+Samsung Exynos Generic Boards (for mobile devices)
+==================================================
+
+Overview
+--------
+This document describes how to build and run U-Boot for Samsung Exynos generic
+boards. Boards are expected to boot with a primary bootloader, such as S-BOOT or
+S-LK, which hands off control to U-Boot, disguised as an Android boot image.
+
+U-Boot is packed with multiple FDTs since it targets multiple boards. The
+appropriate FDT is selected during boot. Additionally, a DTB is also required
+for embedding in the Android boot image. The previous bootloader can apply
+useful overlays on it. Both DTBs are consulted for figuring out the memory
+layout.
+
+Installation
+------------
+Building
+^^^^^^^^
+To buiid U-Boot, run the following commands
+
+.. prompt:: bash $
+
+	make CROSS_COMPILE=aarch64-linux-gnu- O=.output exynos-mobile_defconfig
+	make CROSS_COMPILE=aarch64-linux-gnu- O=.output -j$(nproc)
+
+If succcessful, the U-Boot binary will be present in ``.output/u-boot.bin``.
+
+Preparation
+^^^^^^^^^^^
+The U-Boot binary is not flashable as-is, it needs to be encapsulated in an
+Android boot image. Since it supports multiple boards, and devices have
+different requirements (thanks to the lack of standards), this step varies
+depending on your target.
+
+Exynos 7870 Boards
+""""""""""""""""""
+Create the following devicetree (named ``stub.dts``)
+
+.. code-block:: devicetree
+
+	/dts-v1/;
+
+	/ {
+		compatible = "samsung,exynos7870";
+		#address-cells = <2>;
+		#size-cells = <1>;
+
+		model_info-chip = <7870>;
+		model_info-hw_rev = <0>;
+		model_info-hw_rev_end = <255>;
+
+		chosen {
+		};
+
+		memory@80000000 {
+			device_type = "memory";
+			reg = <0x0 0x80000000 0x0>;
+		};
+
+		memory@100000000 {
+			device_type = "memory";
+			reg = <0x1 0x00000000 0x0>;
+		};
+	};
+
+The chosen node and memory ranges are populated by S-BOOT.
+
+Compile it to a devicetree blob, then use ``dtbTool-exynos`` in order to pack it
+in the QCDT format [1]_, using the following commands:
+
+.. prompt:: bash $
+
+	dtc -I dts -O dtb -o stub.dtb stub.dts
+	dtbTool-exynos -o stub.dt.img stub.dtb
+
+Finally, use mkbootimg by osm0sis [2]_ to generate the boot image:
+
+.. prompt:: bash $
+
+	mkbootimg -o u-boot.img \
+		--kernel	.output/u-boot.bin \
+		--dt		stub.dt.img
+
+Offsets are not provided to ``mkbootimg`` as S-BOOT ignores them.
+
+Flashing
+^^^^^^^^
+If flashing for the first time, it must be done via Samsung's Download (Odin)
+mode. Heimdall can be used for flashing, like so:
+
+.. prompt:: bash $
+
+	heimdall flash --BOOT u-boot.img
+
+However, if U-Boot is already installed, you may also use its fastboot interface
+for flashing. Boot into the boot menu by holding the volume down key. Enable
+fastboot mode from there, connect the device to your host, then run:
+
+.. prompt:: bash $
+
+	fastboot flash boot u-boot.img
+
+To flash an OS image in internal storage, fastboot is a reliable option.
+
+References
+----------
+.. [1] https://wiki.postmarketos.org/wiki/QCDT
+.. [2] https://github.com/osm0sis/mkbootimg
diff --git a/doc/board/samsung/index.rst b/doc/board/samsung/index.rst
index 1b92c9518a57df102c2b64ff934b460548ce3d53..1fbe88130c049e1a33d22ae9230fb60ddccea131 100644
--- a/doc/board/samsung/index.rst
+++ b/doc/board/samsung/index.rst
@@ -8,4 +8,5 @@ Samsung
 
    axy17lte
    e850-96
+   exynos-mobile
    n1
diff --git a/include/configs/exynos-mobile.h b/include/configs/exynos-mobile.h
new file mode 100644
index 0000000000000000000000000000000000000000..862db5779ef4c9ff7f53bef78d7cee5107b7226e
--- /dev/null
+++ b/include/configs/exynos-mobile.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Samsung Exynos Generic Board Configuration (for mobile devices)
+ *
+ * Copyright (C) 2025 Kaustabh Chakraborty <kauschluss@disroot.org>
+ */
+
+#ifndef __CONFIG_EXYNOS_MOBILE_H
+#define __CONFIG_EXYNOS_MOBILE_H
+
+#define CPU_RELEASE_ADDR	secondary_boot_addr
+#define CFG_SYS_BAUDRATE_TABLE	{9600, 115200}
+
+#endif /* __CONFIG_EXYNOS_MOBILE_H */

---
base-commit: 582a04763aa80738c1c8ac60c47d1a5159a42833
change-id: 20251017-board-exynos-mobile-7c7d43832693

Best regards,
-- 
Kaustabh Chakraborty <kauschluss@disroot.org>

Re: [PATCH] board: samsung: add support for Samsung Exynos mobile device boards

[Henrik Grimler]

Hi Kaustabh,

Nice work on all of the linked patches!

On Fri, Oct 17, 2025 at 10:07:35PM +0530, Kaustabh Chakraborty wrote:
> Add support for a generic platform which intends to support multiple
> boards powerid by Samsung Exynos SoCs. This patch also includes initial
> support for three boards:
> * Samsung Galaxy A2 Core
> * Samsung Galaxy J6
> * Samsung Galaxy J7 Prime

I think it would be easier to review this if you split the patch in two
parts: first adding docs and common parts, and then the specific parts
for exynos7870 and these devices.

> Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
> ---
> This patch has the following dependencies:
> (NOTE: `x` indicates applied)
> 
> armv8-broken-cntfrq		- https://patch.msgid.link/20251017-armv8-broken-cntfrq-v2-1-1e043cbb657e@disroot.org
> clk-exynos7870			- https://patch.msgid.link/20251017-clk-exynos7870-v1-0-83f90d425699@disroot.org
> gpio-s5p-bank-fix		- https://patch.msgid.link/20251017-gpio-s5p-bank-fix-v1-1-41050462cea5@disroot.org
> i2c-hs-exynos7			- https://patch.msgid.link/20251017-i2c-hs-exynos7-v1-1-ca080895d4b6@disroot.org
> mmc-dw-exynos7870		- https://patch.msgid.link/20251017-mmc-dw-exynos7870-v1-0-a2c5139d9afe@disroot.org
> phy-usb-exynos7870		- https://patch.msgid.link/20251017-phy-usb-exynos7870-v1-0-5885b00f0c87@disroot.org
> pinctrl-exynos7870		- https://patch.msgid.link/20251017-pinctrl-exynos7870-v1-0-beaa92f95a0c@disroot.org
> power-pmic-regulator-s2mpu05	- https://patch.msgid.link/20251017-power-pmic-regulator-s2mpu05-v1-0-91cadc0f4156@disroot.org
> serial-s5p-exynos8895		- https://patch.msgid.link/20251017-serial-s5p-exynos8895-v1-1-b412dd112cfd@disroot.org
> soc-pmu-exynos7			- https://patch.msgid.link/20251017-soc-pmu-exynos7-v1-1-553d18eaab0d@disroot.org
> usb-dwc3-exynos7870		- https://patch.msgid.link/20251017-usb-dwc3-exynos7870-v1-0-fe46e2ed1908@disroot.org
> ---
>  arch/arm/mach-exynos/Kconfig                       |  11 +-
>  board/samsung/exynos-mobile/Kconfig                |  18 +
>  board/samsung/exynos-mobile/MAINTAINERS            |   6 +
>  board/samsung/exynos-mobile/Makefile               |   5 +
>  .../samsung/exynos-mobile/debug-exynos7870.config  |   7 +
>  board/samsung/exynos-mobile/exynos-mobile.c        | 372 +++++++++++++++++++++
>  board/samsung/exynos-mobile/exynos-mobile.env      |  18 +
>  configs/exynos-mobile_defconfig                    |  71 ++++
>  doc/board/samsung/exynos-mobile.rst                | 112 +++++++
>  doc/board/samsung/index.rst                        |   1 +
>  include/configs/exynos-mobile.h                    |  14 +
>  11 files changed, 634 insertions(+), 1 deletion(-)

[ skipping to docs for now ]

> diff --git a/doc/board/samsung/exynos-mobile.rst b/doc/board/samsung/exynos-mobile.rst
> new file mode 100644
> index 0000000000000000000000000000000000000000..6390c66ffc38a41f01cb51c7406397cfc5a3d223
> --- /dev/null
> +++ b/doc/board/samsung/exynos-mobile.rst
> @@ -0,0 +1,112 @@
> +.. SPDX-License-Identifier: GPL-2.0+
> +.. sectionauthor:: Kaustabh Chakraborty <kauschluss@disroot.org>
> +
> +Samsung Exynos Generic Boards (for mobile devices)
> +==================================================
> +
> +Overview
> +--------
> +This document describes how to build and run U-Boot for Samsung Exynos generic
> +boards. Boards are expected to boot with a primary bootloader, such as S-BOOT or
> +S-LK, which hands off control to U-Boot, disguised as an Android boot image.

In my opinion exynos-mobile is a bit too generic. From the docs here
it seems plan is to support devices that support android boot images
with dt in Samsung's qcdt format. The oldest Exynos mobile device do
not even support boot images though, and dt images has only been
around since something like 2015. If I am not mistaken the newest
devices also does not use dt images.

> +U-Boot is packed with multiple FDTs since it targets multiple boards. The
> +appropriate FDT is selected during boot. Additionally, a DTB is also required
> +for embedding in the Android boot image. The previous bootloader can apply
> +useful overlays on it. Both DTBs are consulted for figuring out the memory
> +layout.

> +Installation
> +------------
> +Building
> +^^^^^^^^
> +To buiid U-Boot, run the following commands

Typo, buiid -> build

> +.. prompt:: bash $
> +
> +	make CROSS_COMPILE=aarch64-linux-gnu- O=.output exynos-mobile_defconfig
> +	make CROSS_COMPILE=aarch64-linux-gnu- O=.output -j$(nproc)

I think CROSS_COMPILE=aarch64-linux-gnu- can be dropped from the example, or are only
aarch64 devices supported?

> +If succcessful, the U-Boot binary will be present in ``.output/u-boot.bin``.

Typo, succcessful -> successful.

> +
> +Preparation
> +^^^^^^^^^^^
> +The U-Boot binary is not flashable as-is, it needs to be encapsulated in an
> +Android boot image. Since it supports multiple boards, and devices have
> +different requirements (thanks to the lack of standards), this step varies

I think `(thanks to the lack of standards)` is a bit opinionated, and
does not really add anything here, could you please remove it?

> +depending on your target.
> +
> +Exynos 7870 Boards
> +""""""""""""""""""
> +Create the following devicetree (named ``stub.dts``)
> +
> +.. code-block:: devicetree
> +
> +	/dts-v1/;
> +
> +	/ {
> +		compatible = "samsung,exynos7870";
> +		#address-cells = <2>;
> +		#size-cells = <1>;
> +
> +		model_info-chip = <7870>;
> +		model_info-hw_rev = <0>;
> +		model_info-hw_rev_end = <255>;
> +
> +		chosen {
> +		};
> +
> +		memory@80000000 {
> +			device_type = "memory";
> +			reg = <0x0 0x80000000 0x0>;
> +		};
> +
> +		memory@100000000 {
> +			device_type = "memory";
> +			reg = <0x1 0x00000000 0x0>;
> +		};
> +	};
> +
> +The chosen node and memory ranges are populated by S-BOOT.
> +
> +Compile it to a devicetree blob, then use ``dtbTool-exynos`` in order to pack it
> +in the QCDT format [1]_, using the following commands:
> +
> +.. prompt:: bash $
> +
> +	dtc -I dts -O dtb -o stub.dtb stub.dts
> +	dtbTool-exynos -o stub.dt.img stub.dtb
> +
> +Finally, use mkbootimg by osm0sis [2]_ to generate the boot image:
> +
> +.. prompt:: bash $
> +
> +	mkbootimg -o u-boot.img \
> +		--kernel	.output/u-boot.bin \
> +		--dt		stub.dt.img
> +
> +Offsets are not provided to ``mkbootimg`` as S-BOOT ignores them.
> +
> +Flashing
> +^^^^^^^^
> +If flashing for the first time, it must be done via Samsung's Download (Odin)
> +mode. Heimdall can be used for flashing, like so:

Maybe it would be useful to link to Heimdall in references as well.

Best regards,
Henrik Grimler

> +.. prompt:: bash $
> +
> +	heimdall flash --BOOT u-boot.img
> +
> +However, if U-Boot is already installed, you may also use its fastboot interface
> +for flashing. Boot into the boot menu by holding the volume down key. Enable
> +fastboot mode from there, connect the device to your host, then run:
> +
> +.. prompt:: bash $
> +
> +	fastboot flash boot u-boot.img
> +
> +To flash an OS image in internal storage, fastboot is a reliable option.
> +
> +References
> +----------
> +.. [1] https://wiki.postmarketos.org/wiki/QCDT
> +.. [2] https://github.com/osm0sis/mkbootimg
> diff --git a/doc/board/samsung/index.rst b/doc/board/samsung/index.rst
> index 1b92c9518a57df102c2b64ff934b460548ce3d53..1fbe88130c049e1a33d22ae9230fb60ddccea131 100644
> --- a/doc/board/samsung/index.rst
> +++ b/doc/board/samsung/index.rst
> @@ -8,4 +8,5 @@ Samsung
>  
>     axy17lte
>     e850-96
> +   exynos-mobile
>     n1
> diff --git a/include/configs/exynos-mobile.h b/include/configs/exynos-mobile.h
> new file mode 100644
> index 0000000000000000000000000000000000000000..862db5779ef4c9ff7f53bef78d7cee5107b7226e
> --- /dev/null
> +++ b/include/configs/exynos-mobile.h
> @@ -0,0 +1,14 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Samsung Exynos Generic Board Configuration (for mobile devices)
> + *
> + * Copyright (C) 2025 Kaustabh Chakraborty <kauschluss@disroot.org>
> + */
> +
> +#ifndef __CONFIG_EXYNOS_MOBILE_H
> +#define __CONFIG_EXYNOS_MOBILE_H
> +
> +#define CPU_RELEASE_ADDR	secondary_boot_addr
> +#define CFG_SYS_BAUDRATE_TABLE	{9600, 115200}
> +
> +#endif /* __CONFIG_EXYNOS_MOBILE_H */
> 
> ---
> base-commit: 582a04763aa80738c1c8ac60c47d1a5159a42833
> change-id: 20251017-board-exynos-mobile-7c7d43832693
> 
> Best regards,
> -- 
> Kaustabh Chakraborty <kauschluss@disroot.org>
> 

Re: [PATCH] board: samsung: add support for Samsung Exynos mobile device boards

[Kaustabh Chakraborty]

On 2025-10-17 20:19, Henrik Grimler wrote:
> Hi Kaustabh,
> 
> Nice work on all of the linked patches!
> 
> On Fri, Oct 17, 2025 at 10:07:35PM +0530, Kaustabh Chakraborty wrote:
>> Add support for a generic platform which intends to support multiple
>> boards powerid by Samsung Exynos SoCs. This patch also includes 
>> initial
>> support for three boards:
>> * Samsung Galaxy A2 Core
>> * Samsung Galaxy J6
>> * Samsung Galaxy J7 Prime
> 
> I think it would be easier to review this if you split the patch in two
> parts: first adding docs and common parts, and then the specific parts
> for exynos7870 and these devices.
> 
>> Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
>> ---
>> This patch has the following dependencies:
>> (NOTE: `x` indicates applied)
>> 
>> armv8-broken-cntfrq		- 
>> https://patch.msgid.link/20251017-armv8-broken-cntfrq-v2-1-1e043cbb657e@disroot.org
>> clk-exynos7870			- 
>> https://patch.msgid.link/20251017-clk-exynos7870-v1-0-83f90d425699@disroot.org
>> gpio-s5p-bank-fix		- 
>> https://patch.msgid.link/20251017-gpio-s5p-bank-fix-v1-1-41050462cea5@disroot.org
>> i2c-hs-exynos7			- 
>> https://patch.msgid.link/20251017-i2c-hs-exynos7-v1-1-ca080895d4b6@disroot.org
>> mmc-dw-exynos7870		- 
>> https://patch.msgid.link/20251017-mmc-dw-exynos7870-v1-0-a2c5139d9afe@disroot.org
>> phy-usb-exynos7870		- 
>> https://patch.msgid.link/20251017-phy-usb-exynos7870-v1-0-5885b00f0c87@disroot.org
>> pinctrl-exynos7870		- 
>> https://patch.msgid.link/20251017-pinctrl-exynos7870-v1-0-beaa92f95a0c@disroot.org
>> power-pmic-regulator-s2mpu05	- 
>> https://patch.msgid.link/20251017-power-pmic-regulator-s2mpu05-v1-0-91cadc0f4156@disroot.org
>> serial-s5p-exynos8895		- 
>> https://patch.msgid.link/20251017-serial-s5p-exynos8895-v1-1-b412dd112cfd@disroot.org
>> soc-pmu-exynos7			- 
>> https://patch.msgid.link/20251017-soc-pmu-exynos7-v1-1-553d18eaab0d@disroot.org
>> usb-dwc3-exynos7870		- 
>> https://patch.msgid.link/20251017-usb-dwc3-exynos7870-v1-0-fe46e2ed1908@disroot.org
>> ---
>>  arch/arm/mach-exynos/Kconfig                       |  11 +-
>>  board/samsung/exynos-mobile/Kconfig                |  18 +
>>  board/samsung/exynos-mobile/MAINTAINERS            |   6 +
>>  board/samsung/exynos-mobile/Makefile               |   5 +
>>  .../samsung/exynos-mobile/debug-exynos7870.config  |   7 +
>>  board/samsung/exynos-mobile/exynos-mobile.c        | 372 
>> +++++++++++++++++++++
>>  board/samsung/exynos-mobile/exynos-mobile.env      |  18 +
>>  configs/exynos-mobile_defconfig                    |  71 ++++
>>  doc/board/samsung/exynos-mobile.rst                | 112 +++++++
>>  doc/board/samsung/index.rst                        |   1 +
>>  include/configs/exynos-mobile.h                    |  14 +
>>  11 files changed, 634 insertions(+), 1 deletion(-)
> 
> [ skipping to docs for now ]
> 
>> diff --git a/doc/board/samsung/exynos-mobile.rst 
>> b/doc/board/samsung/exynos-mobile.rst
>> new file mode 100644
>> index 
>> 0000000000000000000000000000000000000000..6390c66ffc38a41f01cb51c7406397cfc5a3d223
>> --- /dev/null
>> +++ b/doc/board/samsung/exynos-mobile.rst
>> @@ -0,0 +1,112 @@
>> +.. SPDX-License-Identifier: GPL-2.0+
>> +.. sectionauthor:: Kaustabh Chakraborty <kauschluss@disroot.org>
>> +
>> +Samsung Exynos Generic Boards (for mobile devices)
>> +==================================================
>> +
>> +Overview
>> +--------
>> +This document describes how to build and run U-Boot for Samsung 
>> Exynos generic
>> +boards. Boards are expected to boot with a primary bootloader, such 
>> as S-BOOT or
>> +S-LK, which hands off control to U-Boot, disguised as an Android boot 
>> image.
> 
> In my opinion exynos-mobile is a bit too generic. From the docs here
> it seems plan is to support devices that support android boot images
> with dt in Samsung's qcdt format. The oldest Exynos mobile device do
> not even support boot images though, and dt images has only been
> around since something like 2015. If I am not mistaken the newest
> devices also does not use dt images.

Well no, any Exynos would be supported by this variant, the only
factor is that U-Boot is used as a *secondary* boot loader. QCDT is
specific to the packaging of the u-boot binary (that too, is
located under a 7870-specific section), and if there are any other
packing methods, they can be documented here as well.

That being said, I've found 'exynos-mobile' to be most appropriate
(This is for mobile devices like phones and tablets, where we have
a proprietary primary boot loader). But if you have suggestions for
better names, let me know. :)

> 
>> +U-Boot is packed with multiple FDTs since it targets multiple boards. 
>> The
>> +appropriate FDT is selected during boot. Additionally, a DTB is also 
>> required
>> +for embedding in the Android boot image. The previous bootloader can 
>> apply
>> +useful overlays on it. Both DTBs are consulted for figuring out the 
>> memory
>> +layout.
> 
>> +Installation
>> +------------
>> +Building
>> +^^^^^^^^
>> +To buiid U-Boot, run the following commands
> 
> Typo, buiid -> build
> 
>> +.. prompt:: bash $
>> +
>> +	make CROSS_COMPILE=aarch64-linux-gnu- O=.output 
>> exynos-mobile_defconfig
>> +	make CROSS_COMPILE=aarch64-linux-gnu- O=.output -j$(nproc)
> 
> I think CROSS_COMPILE=aarch64-linux-gnu- can be dropped from the 
> example, or are only
> aarch64 devices supported?

Plans were for aarch64. But if its possible to add armv7 support, then
that would be great! Is multiple arch-es for the same board possible?

> 
>> +If succcessful, the U-Boot binary will be present in 
>> ``.output/u-boot.bin``.
> 
> Typo, succcessful -> successful.
> 
>> +
>> +Preparation
>> +^^^^^^^^^^^
>> +The U-Boot binary is not flashable as-is, it needs to be encapsulated 
>> in an
>> +Android boot image. Since it supports multiple boards, and devices 
>> have
>> +different requirements (thanks to the lack of standards), this step 
>> varies
> 
> I think `(thanks to the lack of standards)` is a bit opinionated, and
> does not really add anything here, could you please remove it?

I agree. Will remove it.

> 
>> +depending on your target.
>> +
>> +Exynos 7870 Boards
>> +""""""""""""""""""
>> +Create the following devicetree (named ``stub.dts``)
>> +
>> +.. code-block:: devicetree
>> +
>> +	/dts-v1/;
>> +
>> +	/ {
>> +		compatible = "samsung,exynos7870";
>> +		#address-cells = <2>;
>> +		#size-cells = <1>;
>> +
>> +		model_info-chip = <7870>;
>> +		model_info-hw_rev = <0>;
>> +		model_info-hw_rev_end = <255>;
>> +
>> +		chosen {
>> +		};
>> +
>> +		memory@80000000 {
>> +			device_type = "memory";
>> +			reg = <0x0 0x80000000 0x0>;
>> +		};
>> +
>> +		memory@100000000 {
>> +			device_type = "memory";
>> +			reg = <0x1 0x00000000 0x0>;
>> +		};
>> +	};
>> +
>> +The chosen node and memory ranges are populated by S-BOOT.
>> +
>> +Compile it to a devicetree blob, then use ``dtbTool-exynos`` in order 
>> to pack it
>> +in the QCDT format [1]_, using the following commands:
>> +
>> +.. prompt:: bash $
>> +
>> +	dtc -I dts -O dtb -o stub.dtb stub.dts
>> +	dtbTool-exynos -o stub.dt.img stub.dtb
>> +
>> +Finally, use mkbootimg by osm0sis [2]_ to generate the boot image:
>> +
>> +.. prompt:: bash $
>> +
>> +	mkbootimg -o u-boot.img \
>> +		--kernel	.output/u-boot.bin \
>> +		--dt		stub.dt.img
>> +
>> +Offsets are not provided to ``mkbootimg`` as S-BOOT ignores them.
>> +
>> +Flashing
>> +^^^^^^^^
>> +If flashing for the first time, it must be done via Samsung's 
>> Download (Odin)
>> +mode. Heimdall can be used for flashing, like so:
> 
> Maybe it would be useful to link to Heimdall in references as well.
> 
> Best regards,
> Henrik Grimler
> 
>> +.. prompt:: bash $
>> +
>> +	heimdall flash --BOOT u-boot.img
>> +
>> +However, if U-Boot is already installed, you may also use its 
>> fastboot interface
>> +for flashing. Boot into the boot menu by holding the volume down key. 
>> Enable
>> +fastboot mode from there, connect the device to your host, then run:
>> +
>> +.. prompt:: bash $
>> +
>> +	fastboot flash boot u-boot.img
>> +
>> +To flash an OS image in internal storage, fastboot is a reliable 
>> option.
>> +
>> +References
>> +----------
>> +.. [1] https://wiki.postmarketos.org/wiki/QCDT
>> +.. [2] https://github.com/osm0sis/mkbootimg
>> diff --git a/doc/board/samsung/index.rst b/doc/board/samsung/index.rst
>> index 
>> 1b92c9518a57df102c2b64ff934b460548ce3d53..1fbe88130c049e1a33d22ae9230fb60ddccea131 
>> 100644
>> --- a/doc/board/samsung/index.rst
>> +++ b/doc/board/samsung/index.rst
>> @@ -8,4 +8,5 @@ Samsung
>> 
>>     axy17lte
>>     e850-96
>> +   exynos-mobile
>>     n1
>> diff --git a/include/configs/exynos-mobile.h 
>> b/include/configs/exynos-mobile.h
>> new file mode 100644
>> index 
>> 0000000000000000000000000000000000000000..862db5779ef4c9ff7f53bef78d7cee5107b7226e
>> --- /dev/null
>> +++ b/include/configs/exynos-mobile.h
>> @@ -0,0 +1,14 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Samsung Exynos Generic Board Configuration (for mobile devices)
>> + *
>> + * Copyright (C) 2025 Kaustabh Chakraborty <kauschluss@disroot.org>
>> + */
>> +
>> +#ifndef __CONFIG_EXYNOS_MOBILE_H
>> +#define __CONFIG_EXYNOS_MOBILE_H
>> +
>> +#define CPU_RELEASE_ADDR	secondary_boot_addr
>> +#define CFG_SYS_BAUDRATE_TABLE	{9600, 115200}
>> +
>> +#endif /* __CONFIG_EXYNOS_MOBILE_H */
>> 
>> ---
>> base-commit: 582a04763aa80738c1c8ac60c47d1a5159a42833
>> change-id: 20251017-board-exynos-mobile-7c7d43832693
>> 
>> Best regards,
>> --
>> Kaustabh Chakraborty <kauschluss@disroot.org>
>> 

Re: [PATCH] board: samsung: add support for Samsung Exynos mobile device board

[Henrik Grimler]

Hi Kaustabh,

On Sat, Oct 18, 2025 at 06:04:35PM +0000, Kaustabh Chakraborty wrote:
> On 2025-10-17 20:19, Henrik Grimler wrote:
> > Hi Kaustabh,
> > 
> > Nice work on all of the linked patches!
> > 
> > On Fri, Oct 17, 2025 at 10:07:35PM +0530, Kaustabh Chakraborty wrote:
> > > Add support for a generic platform which intends to support multiple
> > > boards powerid by Samsung Exynos SoCs. This patch also includes
> > > initial
> > > support for three boards:
> > > * Samsung Galaxy A2 Core
> > > * Samsung Galaxy J6
> > > * Samsung Galaxy J7 Prime
> > 
> > I think it would be easier to review this if you split the patch in two
> > parts: first adding docs and common parts, and then the specific parts
> > for exynos7870 and these devices.
> > 
> > > Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
> > > ---
> > > This patch has the following dependencies:
> > > (NOTE: `x` indicates applied)
> > > 
> > > armv8-broken-cntfrq		- https://patch.msgid.link/20251017-armv8-broken-cntfrq-v2-1-1e043cbb657e@disroot.org
> > > clk-exynos7870			- https://patch.msgid.link/20251017-clk-exynos7870-v1-0-83f90d425699@disroot.org
> > > gpio-s5p-bank-fix		- https://patch.msgid.link/20251017-gpio-s5p-bank-fix-v1-1-41050462cea5@disroot.org
> > > i2c-hs-exynos7			- https://patch.msgid.link/20251017-i2c-hs-exynos7-v1-1-ca080895d4b6@disroot.org
> > > mmc-dw-exynos7870		- https://patch.msgid.link/20251017-mmc-dw-exynos7870-v1-0-a2c5139d9afe@disroot.org
> > > phy-usb-exynos7870		- https://patch.msgid.link/20251017-phy-usb-exynos7870-v1-0-5885b00f0c87@disroot.org
> > > pinctrl-exynos7870		- https://patch.msgid.link/20251017-pinctrl-exynos7870-v1-0-beaa92f95a0c@disroot.org
> > > power-pmic-regulator-s2mpu05	- https://patch.msgid.link/20251017-power-pmic-regulator-s2mpu05-v1-0-91cadc0f4156@disroot.org
> > > serial-s5p-exynos8895		- https://patch.msgid.link/20251017-serial-s5p-exynos8895-v1-1-b412dd112cfd@disroot.org
> > > soc-pmu-exynos7			- https://patch.msgid.link/20251017-soc-pmu-exynos7-v1-1-553d18eaab0d@disroot.org
> > > usb-dwc3-exynos7870		- https://patch.msgid.link/20251017-usb-dwc3-exynos7870-v1-0-fe46e2ed1908@disroot.org
> > > ---
> > >  arch/arm/mach-exynos/Kconfig                       |  11 +-
> > >  board/samsung/exynos-mobile/Kconfig                |  18 +
> > >  board/samsung/exynos-mobile/MAINTAINERS            |   6 +
> > >  board/samsung/exynos-mobile/Makefile               |   5 +
> > >  .../samsung/exynos-mobile/debug-exynos7870.config  |   7 +
> > >  board/samsung/exynos-mobile/exynos-mobile.c        | 372
> > > +++++++++++++++++++++
> > >  board/samsung/exynos-mobile/exynos-mobile.env      |  18 +
> > >  configs/exynos-mobile_defconfig                    |  71 ++++
> > >  doc/board/samsung/exynos-mobile.rst                | 112 +++++++
> > >  doc/board/samsung/index.rst                        |   1 +
> > >  include/configs/exynos-mobile.h                    |  14 +
> > >  11 files changed, 634 insertions(+), 1 deletion(-)
> > 
> > [ skipping to docs for now ]
> > 
> > > diff --git a/doc/board/samsung/exynos-mobile.rst
> > > b/doc/board/samsung/exynos-mobile.rst
> > > new file mode 100644
> > > index 0000000000000000000000000000000000000000..6390c66ffc38a41f01cb51c7406397cfc5a3d223
> > > --- /dev/null
> > > +++ b/doc/board/samsung/exynos-mobile.rst
> > > @@ -0,0 +1,112 @@
> > > +.. SPDX-License-Identifier: GPL-2.0+
> > > +.. sectionauthor:: Kaustabh Chakraborty <kauschluss@disroot.org>
> > > +
> > > +Samsung Exynos Generic Boards (for mobile devices)
> > > +==================================================
> > > +
> > > +Overview
> > > +--------
> > > +This document describes how to build and run U-Boot for Samsung
> > > Exynos generic
> > > +boards. Boards are expected to boot with a primary bootloader, such
> > > as S-BOOT or
> > > +S-LK, which hands off control to U-Boot, disguised as an Android
> > > boot image.
> > 
> > In my opinion exynos-mobile is a bit too generic. From the docs here
> > it seems plan is to support devices that support android boot images
> > with dt in Samsung's qcdt format. The oldest Exynos mobile device do
> > not even support boot images though, and dt images has only been
> > around since something like 2015. If I am not mistaken the newest
> > devices also does not use dt images.
> 
> Well no, any Exynos would be supported by this variant, the only

Ok, any Exynos, then `disguised as an Android boot image` should be
rephrased, as not all Exynos'es support boot images. Next paragraph
should be updated as well.

> factor is that U-Boot is used as a *secondary* boot loader. QCDT is
> specific to the packaging of the u-boot binary (that too, is
> located under a 7870-specific section), and if there are any other
> packing methods, they can be documented here as well.
> 
> That being said, I've found 'exynos-mobile' to be most appropriate
> (This is for mobile devices like phones and tablets, where we have
> a proprietary primary boot loader). But if you have suggestions for
> better names, let me know. :)

Sure, if any Exynos is supported, then exynos-mobile is fine. 

> > > +U-Boot is packed with multiple FDTs since it targets multiple
> > > boards. The
> > > +appropriate FDT is selected during boot. Additionally, a DTB is
> > > also required
> > > +for embedding in the Android boot image. The previous bootloader
> > > can apply
> > > +useful overlays on it. Both DTBs are consulted for figuring out the
> > > memory
> > > +layout.

Not all Exynos'es have bootloaders that support boot images, and among
the ones that do, not all support dtbs. Please move to 7870 specific
section and/or make the paragraph more generic if it should support
any Exynos.

> > 
> > > +Installation
> > > +------------
> > > +Building
> > > +^^^^^^^^
> > > +To buiid U-Boot, run the following commands
> > 
> > Typo, buiid -> build
> > 
> > > +.. prompt:: bash $
> > > +
> > > +	make CROSS_COMPILE=aarch64-linux-gnu- O=.output
> > > exynos-mobile_defconfig
> > > +	make CROSS_COMPILE=aarch64-linux-gnu- O=.output -j$(nproc)
> > 
> > I think CROSS_COMPILE=aarch64-linux-gnu- can be dropped from the
> > example, or are only
> > aarch64 devices supported?
> 
> Plans were for aarch64. But if its possible to add armv7 support, then
> that would be great! Is multiple arch-es for the same board possible?

Probably not, but not all Exynos'es are armv8, so if instructions
should be for any Exynos then I think it is best to leave $arch out of
the commands.

Best regards,
Henrik Grimler

> > > +If succcessful, the U-Boot binary will be present in
> > > ``.output/u-boot.bin``.
> > 
> > Typo, succcessful -> successful.
> > 
> > > +
> > > +Preparation
> > > +^^^^^^^^^^^
> > > +The U-Boot binary is not flashable as-is, it needs to be
> > > encapsulated in an
> > > +Android boot image. Since it supports multiple boards, and devices
> > > have
> > > +different requirements (thanks to the lack of standards), this step
> > > varies
> > 
> > I think `(thanks to the lack of standards)` is a bit opinionated, and
> > does not really add anything here, could you please remove it?
> 
> I agree. Will remove it.
> 
> > 
> > > +depending on your target.
> > > +
> > > +Exynos 7870 Boards
> > > +""""""""""""""""""
> > > +Create the following devicetree (named ``stub.dts``)
> > > +
> > > +.. code-block:: devicetree
> > > +
> > > +	/dts-v1/;
> > > +
> > > +	/ {
> > > +		compatible = "samsung,exynos7870";
> > > +		#address-cells = <2>;
> > > +		#size-cells = <1>;
> > > +
> > > +		model_info-chip = <7870>;
> > > +		model_info-hw_rev = <0>;
> > > +		model_info-hw_rev_end = <255>;
> > > +
> > > +		chosen {
> > > +		};
> > > +
> > > +		memory@80000000 {
> > > +			device_type = "memory";
> > > +			reg = <0x0 0x80000000 0x0>;
> > > +		};
> > > +
> > > +		memory@100000000 {
> > > +			device_type = "memory";
> > > +			reg = <0x1 0x00000000 0x0>;
> > > +		};
> > > +	};
> > > +
> > > +The chosen node and memory ranges are populated by S-BOOT.
> > > +
> > > +Compile it to a devicetree blob, then use ``dtbTool-exynos`` in
> > > order to pack it
> > > +in the QCDT format [1]_, using the following commands:
> > > +
> > > +.. prompt:: bash $
> > > +
> > > +	dtc -I dts -O dtb -o stub.dtb stub.dts
> > > +	dtbTool-exynos -o stub.dt.img stub.dtb
> > > +
> > > +Finally, use mkbootimg by osm0sis [2]_ to generate the boot image:
> > > +
> > > +.. prompt:: bash $
> > > +
> > > +	mkbootimg -o u-boot.img \
> > > +		--kernel	.output/u-boot.bin \
> > > +		--dt		stub.dt.img
> > > +
> > > +Offsets are not provided to ``mkbootimg`` as S-BOOT ignores them.
> > > +
> > > +Flashing
> > > +^^^^^^^^
> > > +If flashing for the first time, it must be done via Samsung's
> > > Download (Odin)
> > > +mode. Heimdall can be used for flashing, like so:
> > 
> > Maybe it would be useful to link to Heimdall in references as well.
> > 
> > Best regards,
> > Henrik Grimler
> > 
> > > +.. prompt:: bash $
> > > +
> > > +	heimdall flash --BOOT u-boot.img
> > > +
> > > +However, if U-Boot is already installed, you may also use its
> > > fastboot interface
> > > +for flashing. Boot into the boot menu by holding the volume down
> > > key. Enable
> > > +fastboot mode from there, connect the device to your host, then run:
> > > +
> > > +.. prompt:: bash $
> > > +
> > > +	fastboot flash boot u-boot.img
> > > +
> > > +To flash an OS image in internal storage, fastboot is a reliable
> > > option.
> > > +
> > > +References
> > > +----------
> > > +.. [1] https://wiki.postmarketos.org/wiki/QCDT
> > > +.. [2] https://github.com/osm0sis/mkbootimg
> > > diff --git a/doc/board/samsung/index.rst b/doc/board/samsung/index.rst
> > > index 1b92c9518a57df102c2b64ff934b460548ce3d53..1fbe88130c049e1a33d22ae9230fb60ddccea131
> > > 100644
> > > --- a/doc/board/samsung/index.rst
> > > +++ b/doc/board/samsung/index.rst
> > > @@ -8,4 +8,5 @@ Samsung
> > > 
> > >     axy17lte
> > >     e850-96
> > > +   exynos-mobile
> > >     n1
> > > diff --git a/include/configs/exynos-mobile.h
> > > b/include/configs/exynos-mobile.h
> > > new file mode 100644
> > > index 0000000000000000000000000000000000000000..862db5779ef4c9ff7f53bef78d7cee5107b7226e
> > > --- /dev/null
> > > +++ b/include/configs/exynos-mobile.h
> > > @@ -0,0 +1,14 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > +/*
> > > + * Samsung Exynos Generic Board Configuration (for mobile devices)
> > > + *
> > > + * Copyright (C) 2025 Kaustabh Chakraborty <kauschluss@disroot.org>
> > > + */
> > > +
> > > +#ifndef __CONFIG_EXYNOS_MOBILE_H
> > > +#define __CONFIG_EXYNOS_MOBILE_H
> > > +
> > > +#define CPU_RELEASE_ADDR	secondary_boot_addr
> > > +#define CFG_SYS_BAUDRATE_TABLE	{9600, 115200}
> > > +
> > > +#endif /* __CONFIG_EXYNOS_MOBILE_H */
> > > 
> > > ---
> > > base-commit: 582a04763aa80738c1c8ac60c47d1a5159a42833
> > > change-id: 20251017-board-exynos-mobile-7c7d43832693
> > > 
> > > Best regards,
> > > --
> > > Kaustabh Chakraborty <kauschluss@disroot.org>
> > > 

Re: [PATCH] board: samsung: add support for Samsung Exynos mobile device board

[Kaustabh Chakraborty]

On 2025-10-18 19:25, Henrik Grimler wrote:
> Hi Kaustabh,
> 
> On Sat, Oct 18, 2025 at 06:04:35PM +0000, Kaustabh Chakraborty wrote:
>> On 2025-10-17 20:19, Henrik Grimler wrote:
>> > Hi Kaustabh,
>> >
>> > Nice work on all of the linked patches!
>> >
>> > On Fri, Oct 17, 2025 at 10:07:35PM +0530, Kaustabh Chakraborty wrote:
>> > > Add support for a generic platform which intends to support multiple
>> > > boards powerid by Samsung Exynos SoCs. This patch also includes
>> > > initial
>> > > support for three boards:
>> > > * Samsung Galaxy A2 Core
>> > > * Samsung Galaxy J6
>> > > * Samsung Galaxy J7 Prime
>> >
>> > I think it would be easier to review this if you split the patch in two
>> > parts: first adding docs and common parts, and then the specific parts
>> > for exynos7870 and these devices.
>> >
>> > > Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
>> > > ---
>> > > This patch has the following dependencies:
>> > > (NOTE: `x` indicates applied)
>> > >
>> > > armv8-broken-cntfrq		- https://patch.msgid.link/20251017-armv8-broken-cntfrq-v2-1-1e043cbb657e@disroot.org
>> > > clk-exynos7870			- https://patch.msgid.link/20251017-clk-exynos7870-v1-0-83f90d425699@disroot.org
>> > > gpio-s5p-bank-fix		- https://patch.msgid.link/20251017-gpio-s5p-bank-fix-v1-1-41050462cea5@disroot.org
>> > > i2c-hs-exynos7			- https://patch.msgid.link/20251017-i2c-hs-exynos7-v1-1-ca080895d4b6@disroot.org
>> > > mmc-dw-exynos7870		- https://patch.msgid.link/20251017-mmc-dw-exynos7870-v1-0-a2c5139d9afe@disroot.org
>> > > phy-usb-exynos7870		- https://patch.msgid.link/20251017-phy-usb-exynos7870-v1-0-5885b00f0c87@disroot.org
>> > > pinctrl-exynos7870		- https://patch.msgid.link/20251017-pinctrl-exynos7870-v1-0-beaa92f95a0c@disroot.org
>> > > power-pmic-regulator-s2mpu05	- https://patch.msgid.link/20251017-power-pmic-regulator-s2mpu05-v1-0-91cadc0f4156@disroot.org
>> > > serial-s5p-exynos8895		- https://patch.msgid.link/20251017-serial-s5p-exynos8895-v1-1-b412dd112cfd@disroot.org
>> > > soc-pmu-exynos7			- https://patch.msgid.link/20251017-soc-pmu-exynos7-v1-1-553d18eaab0d@disroot.org
>> > > usb-dwc3-exynos7870		- https://patch.msgid.link/20251017-usb-dwc3-exynos7870-v1-0-fe46e2ed1908@disroot.org
>> > > ---
>> > >  arch/arm/mach-exynos/Kconfig                       |  11 +-
>> > >  board/samsung/exynos-mobile/Kconfig                |  18 +
>> > >  board/samsung/exynos-mobile/MAINTAINERS            |   6 +
>> > >  board/samsung/exynos-mobile/Makefile               |   5 +
>> > >  .../samsung/exynos-mobile/debug-exynos7870.config  |   7 +
>> > >  board/samsung/exynos-mobile/exynos-mobile.c        | 372
>> > > +++++++++++++++++++++
>> > >  board/samsung/exynos-mobile/exynos-mobile.env      |  18 +
>> > >  configs/exynos-mobile_defconfig                    |  71 ++++
>> > >  doc/board/samsung/exynos-mobile.rst                | 112 +++++++
>> > >  doc/board/samsung/index.rst                        |   1 +
>> > >  include/configs/exynos-mobile.h                    |  14 +
>> > >  11 files changed, 634 insertions(+), 1 deletion(-)
>> >
>> > [ skipping to docs for now ]
>> >
>> > > diff --git a/doc/board/samsung/exynos-mobile.rst
>> > > b/doc/board/samsung/exynos-mobile.rst
>> > > new file mode 100644
>> > > index 0000000000000000000000000000000000000000..6390c66ffc38a41f01cb51c7406397cfc5a3d223
>> > > --- /dev/null
>> > > +++ b/doc/board/samsung/exynos-mobile.rst
>> > > @@ -0,0 +1,112 @@
>> > > +.. SPDX-License-Identifier: GPL-2.0+
>> > > +.. sectionauthor:: Kaustabh Chakraborty <kauschluss@disroot.org>
>> > > +
>> > > +Samsung Exynos Generic Boards (for mobile devices)
>> > > +==================================================
>> > > +
>> > > +Overview
>> > > +--------
>> > > +This document describes how to build and run U-Boot for Samsung
>> > > Exynos generic
>> > > +boards. Boards are expected to boot with a primary bootloader, such
>> > > as S-BOOT or
>> > > +S-LK, which hands off control to U-Boot, disguised as an Android
>> > > boot image.
>> >
>> > In my opinion exynos-mobile is a bit too generic. From the docs here
>> > it seems plan is to support devices that support android boot images
>> > with dt in Samsung's qcdt format. The oldest Exynos mobile device do
>> > not even support boot images though, and dt images has only been
>> > around since something like 2015. If I am not mistaken the newest
>> > devices also does not use dt images.
>> 
>> Well no, any Exynos would be supported by this variant, the only
> 
> Ok, any Exynos, then `disguised as an Android boot image` should be
> rephrased, as not all Exynos'es support boot images. Next paragraph
> should be updated as well.
> 
>> factor is that U-Boot is used as a *secondary* boot loader. QCDT is
>> specific to the packaging of the u-boot binary (that too, is
>> located under a 7870-specific section), and if there are any other
>> packing methods, they can be documented here as well.
>> 
>> That being said, I've found 'exynos-mobile' to be most appropriate
>> (This is for mobile devices like phones and tablets, where we have
>> a proprietary primary boot loader). But if you have suggestions for
>> better names, let me know. :)
> 
> Sure, if any Exynos is supported, then exynos-mobile is fine.
> 
>> > > +U-Boot is packed with multiple FDTs since it targets multiple
>> > > boards. The
>> > > +appropriate FDT is selected during boot. Additionally, a DTB is
>> > > also required
>> > > +for embedding in the Android boot image. The previous bootloader
>> > > can apply
>> > > +useful overlays on it. Both DTBs are consulted for figuring out the
>> > > memory
>> > > +layout.
> 
> Not all Exynos'es have bootloaders that support boot images, and among
> the ones that do, not all support dtbs. Please move to 7870 specific
> section and/or make the paragraph more generic if it should support
> any Exynos.
> 
>> >
>> > > +Installation
>> > > +------------
>> > > +Building
>> > > +^^^^^^^^
>> > > +To buiid U-Boot, run the following commands
>> >
>> > Typo, buiid -> build
>> >
>> > > +.. prompt:: bash $
>> > > +
>> > > +	make CROSS_COMPILE=aarch64-linux-gnu- O=.output
>> > > exynos-mobile_defconfig
>> > > +	make CROSS_COMPILE=aarch64-linux-gnu- O=.output -j$(nproc)
>> >
>> > I think CROSS_COMPILE=aarch64-linux-gnu- can be dropped from the
>> > example, or are only
>> > aarch64 devices supported?
>> 
>> Plans were for aarch64. But if its possible to add armv7 support, then
>> that would be great! Is multiple arch-es for the same board possible?
> 
> Probably not, but not all Exynos'es are armv8, so if instructions
> should be for any Exynos then I think it is best to leave $arch out of
> the commands.

I get that, but the board file even uses a lot of armv8 specific stuff
(#include <asm/armv8/mmu.h>) and I don't have any armv7 devices to
implement or test. So I am kind of unsure as of what to do here.

I may as well add a paragraph for cross-compilers, but then implicitly
claiming that armv7 is supported while it remains unsupported doesn't
sit right with me.

And doing this probably requires two defconfigs - one for armv7, another
for armv8. There's quite a bit of work required for separation, and I
am not sure anymore if I should continue to brand it as "all exynos"
(though I'd love to have it that way), or upstream in this condition
and figure out later.

> 
> Best regards,
> Henrik Grimler
> 
>> > > +If succcessful, the U-Boot binary will be present in
>> > > ``.output/u-boot.bin``.
>> >
>> > Typo, succcessful -> successful.
>> >
>> > > +
>> > > +Preparation
>> > > +^^^^^^^^^^^
>> > > +The U-Boot binary is not flashable as-is, it needs to be
>> > > encapsulated in an
>> > > +Android boot image. Since it supports multiple boards, and devices
>> > > have
>> > > +different requirements (thanks to the lack of standards), this step
>> > > varies
>> >
>> > I think `(thanks to the lack of standards)` is a bit opinionated, and
>> > does not really add anything here, could you please remove it?
>> 
>> I agree. Will remove it.
>> 
>> >
>> > > +depending on your target.
>> > > +
>> > > +Exynos 7870 Boards
>> > > +""""""""""""""""""
>> > > +Create the following devicetree (named ``stub.dts``)
>> > > +
>> > > +.. code-block:: devicetree
>> > > +
>> > > +	/dts-v1/;
>> > > +
>> > > +	/ {
>> > > +		compatible = "samsung,exynos7870";
>> > > +		#address-cells = <2>;
>> > > +		#size-cells = <1>;
>> > > +
>> > > +		model_info-chip = <7870>;
>> > > +		model_info-hw_rev = <0>;
>> > > +		model_info-hw_rev_end = <255>;
>> > > +
>> > > +		chosen {
>> > > +		};
>> > > +
>> > > +		memory@80000000 {
>> > > +			device_type = "memory";
>> > > +			reg = <0x0 0x80000000 0x0>;
>> > > +		};
>> > > +
>> > > +		memory@100000000 {
>> > > +			device_type = "memory";
>> > > +			reg = <0x1 0x00000000 0x0>;
>> > > +		};
>> > > +	};
>> > > +
>> > > +The chosen node and memory ranges are populated by S-BOOT.
>> > > +
>> > > +Compile it to a devicetree blob, then use ``dtbTool-exynos`` in
>> > > order to pack it
>> > > +in the QCDT format [1]_, using the following commands:
>> > > +
>> > > +.. prompt:: bash $
>> > > +
>> > > +	dtc -I dts -O dtb -o stub.dtb stub.dts
>> > > +	dtbTool-exynos -o stub.dt.img stub.dtb
>> > > +
>> > > +Finally, use mkbootimg by osm0sis [2]_ to generate the boot image:
>> > > +
>> > > +.. prompt:: bash $
>> > > +
>> > > +	mkbootimg -o u-boot.img \
>> > > +		--kernel	.output/u-boot.bin \
>> > > +		--dt		stub.dt.img
>> > > +
>> > > +Offsets are not provided to ``mkbootimg`` as S-BOOT ignores them.
>> > > +
>> > > +Flashing
>> > > +^^^^^^^^
>> > > +If flashing for the first time, it must be done via Samsung's
>> > > Download (Odin)
>> > > +mode. Heimdall can be used for flashing, like so:
>> >
>> > Maybe it would be useful to link to Heimdall in references as well.
>> >
>> > Best regards,
>> > Henrik Grimler
>> >
>> > > +.. prompt:: bash $
>> > > +
>> > > +	heimdall flash --BOOT u-boot.img
>> > > +
>> > > +However, if U-Boot is already installed, you may also use its
>> > > fastboot interface
>> > > +for flashing. Boot into the boot menu by holding the volume down
>> > > key. Enable
>> > > +fastboot mode from there, connect the device to your host, then run:
>> > > +
>> > > +.. prompt:: bash $
>> > > +
>> > > +	fastboot flash boot u-boot.img
>> > > +
>> > > +To flash an OS image in internal storage, fastboot is a reliable
>> > > option.
>> > > +
>> > > +References
>> > > +----------
>> > > +.. [1] https://wiki.postmarketos.org/wiki/QCDT
>> > > +.. [2] https://github.com/osm0sis/mkbootimg
>> > > diff --git a/doc/board/samsung/index.rst b/doc/board/samsung/index.rst
>> > > index 1b92c9518a57df102c2b64ff934b460548ce3d53..1fbe88130c049e1a33d22ae9230fb60ddccea131
>> > > 100644
>> > > --- a/doc/board/samsung/index.rst
>> > > +++ b/doc/board/samsung/index.rst
>> > > @@ -8,4 +8,5 @@ Samsung
>> > >
>> > >     axy17lte
>> > >     e850-96
>> > > +   exynos-mobile
>> > >     n1
>> > > diff --git a/include/configs/exynos-mobile.h
>> > > b/include/configs/exynos-mobile.h
>> > > new file mode 100644
>> > > index 0000000000000000000000000000000000000000..862db5779ef4c9ff7f53bef78d7cee5107b7226e
>> > > --- /dev/null
>> > > +++ b/include/configs/exynos-mobile.h
>> > > @@ -0,0 +1,14 @@
>> > > +/* SPDX-License-Identifier: GPL-2.0 */
>> > > +/*
>> > > + * Samsung Exynos Generic Board Configuration (for mobile devices)
>> > > + *
>> > > + * Copyright (C) 2025 Kaustabh Chakraborty <kauschluss@disroot.org>
>> > > + */
>> > > +
>> > > +#ifndef __CONFIG_EXYNOS_MOBILE_H
>> > > +#define __CONFIG_EXYNOS_MOBILE_H
>> > > +
>> > > +#define CPU_RELEASE_ADDR	secondary_boot_addr
>> > > +#define CFG_SYS_BAUDRATE_TABLE	{9600, 115200}
>> > > +
>> > > +#endif /* __CONFIG_EXYNOS_MOBILE_H */
>> > >
>> > > ---
>> > > base-commit: 582a04763aa80738c1c8ac60c47d1a5159a42833
>> > > change-id: 20251017-board-exynos-mobile-7c7d43832693
>> > >
>> > > Best regards,
>> > > --
>> > > Kaustabh Chakraborty <kauschluss@disroot.org>
>> > >

Re: [PATCH] board: samsung: add support for Samsung Exynos mobile device board

[Henrik Grimler]

Hi Kaustabh,

On Tue, Oct 21, 2025 at 01:49:46PM +0000, Kaustabh Chakraborty wrote:
> On 2025-10-18 19:25, Henrik Grimler wrote:
> > Hi Kaustabh,
> > 
> > On Sat, Oct 18, 2025 at 06:04:35PM +0000, Kaustabh Chakraborty wrote:
> > > On 2025-10-17 20:19, Henrik Grimler wrote:
> > > > Hi Kaustabh,
> > > >
> > > > Nice work on all of the linked patches!
> > > >
> > > > On Fri, Oct 17, 2025 at 10:07:35PM +0530, Kaustabh Chakraborty wrote:
> > > > > Add support for a generic platform which intends to support multiple
> > > > > boards powerid by Samsung Exynos SoCs. This patch also includes
> > > > > initial
> > > > > support for three boards:
> > > > > * Samsung Galaxy A2 Core
> > > > > * Samsung Galaxy J6
> > > > > * Samsung Galaxy J7 Prime
> > > >
> > > > I think it would be easier to review this if you split the patch in two
> > > > parts: first adding docs and common parts, and then the specific parts
> > > > for exynos7870 and these devices.
> > > >
> > > > > Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
> > > > > ---
> > > > > This patch has the following dependencies:
> > > > > (NOTE: `x` indicates applied)
> > > > >
> > > > > armv8-broken-cntfrq		- https://patch.msgid.link/20251017-armv8-broken-cntfrq-v2-1-1e043cbb657e@disroot.org
> > > > > clk-exynos7870			- https://patch.msgid.link/20251017-clk-exynos7870-v1-0-83f90d425699@disroot.org
> > > > > gpio-s5p-bank-fix		- https://patch.msgid.link/20251017-gpio-s5p-bank-fix-v1-1-41050462cea5@disroot.org
> > > > > i2c-hs-exynos7			- https://patch.msgid.link/20251017-i2c-hs-exynos7-v1-1-ca080895d4b6@disroot.org
> > > > > mmc-dw-exynos7870		- https://patch.msgid.link/20251017-mmc-dw-exynos7870-v1-0-a2c5139d9afe@disroot.org
> > > > > phy-usb-exynos7870		- https://patch.msgid.link/20251017-phy-usb-exynos7870-v1-0-5885b00f0c87@disroot.org
> > > > > pinctrl-exynos7870		- https://patch.msgid.link/20251017-pinctrl-exynos7870-v1-0-beaa92f95a0c@disroot.org
> > > > > power-pmic-regulator-s2mpu05	- https://patch.msgid.link/20251017-power-pmic-regulator-s2mpu05-v1-0-91cadc0f4156@disroot.org
> > > > > serial-s5p-exynos8895		- https://patch.msgid.link/20251017-serial-s5p-exynos8895-v1-1-b412dd112cfd@disroot.org
> > > > > soc-pmu-exynos7			- https://patch.msgid.link/20251017-soc-pmu-exynos7-v1-1-553d18eaab0d@disroot.org
> > > > > usb-dwc3-exynos7870		- https://patch.msgid.link/20251017-usb-dwc3-exynos7870-v1-0-fe46e2ed1908@disroot.org
> > > > > ---
> > > > >  arch/arm/mach-exynos/Kconfig                       |  11 +-
> > > > >  board/samsung/exynos-mobile/Kconfig                |  18 +
> > > > >  board/samsung/exynos-mobile/MAINTAINERS            |   6 +
> > > > >  board/samsung/exynos-mobile/Makefile               |   5 +
> > > > >  .../samsung/exynos-mobile/debug-exynos7870.config  |   7 +
> > > > >  board/samsung/exynos-mobile/exynos-mobile.c        | 372
> > > > > +++++++++++++++++++++
> > > > >  board/samsung/exynos-mobile/exynos-mobile.env      |  18 +
> > > > >  configs/exynos-mobile_defconfig                    |  71 ++++
> > > > >  doc/board/samsung/exynos-mobile.rst                | 112 +++++++
> > > > >  doc/board/samsung/index.rst                        |   1 +
> > > > >  include/configs/exynos-mobile.h                    |  14 +
> > > > >  11 files changed, 634 insertions(+), 1 deletion(-)
> > > >
> > > > [ skipping to docs for now ]
> > > >
> > > > > diff --git a/doc/board/samsung/exynos-mobile.rst
> > > > > b/doc/board/samsung/exynos-mobile.rst
> > > > > new file mode 100644
> > > > > index 0000000000000000000000000000000000000000..6390c66ffc38a41f01cb51c7406397cfc5a3d223
> > > > > --- /dev/null
> > > > > +++ b/doc/board/samsung/exynos-mobile.rst
> > > > > @@ -0,0 +1,112 @@
> > > > > +.. SPDX-License-Identifier: GPL-2.0+
> > > > > +.. sectionauthor:: Kaustabh Chakraborty <kauschluss@disroot.org>
> > > > > +
> > > > > +Samsung Exynos Generic Boards (for mobile devices)
> > > > > +==================================================
> > > > > +
> > > > > +Overview
> > > > > +--------
> > > > > +This document describes how to build and run U-Boot for Samsung
> > > > > Exynos generic
> > > > > +boards. Boards are expected to boot with a primary bootloader, such
> > > > > as S-BOOT or
> > > > > +S-LK, which hands off control to U-Boot, disguised as an Android
> > > > > boot image.
> > > >
> > > > In my opinion exynos-mobile is a bit too generic. From the docs here
> > > > it seems plan is to support devices that support android boot images
> > > > with dt in Samsung's qcdt format. The oldest Exynos mobile device do
> > > > not even support boot images though, and dt images has only been
> > > > around since something like 2015. If I am not mistaken the newest
> > > > devices also does not use dt images.
> > > 
> > > Well no, any Exynos would be supported by this variant, the only
> > 
> > Ok, any Exynos, then `disguised as an Android boot image` should be
> > rephrased, as not all Exynos'es support boot images. Next paragraph
> > should be updated as well.
> > 
> > > factor is that U-Boot is used as a *secondary* boot loader. QCDT is
> > > specific to the packaging of the u-boot binary (that too, is
> > > located under a 7870-specific section), and if there are any other
> > > packing methods, they can be documented here as well.
> > > 
> > > That being said, I've found 'exynos-mobile' to be most appropriate
> > > (This is for mobile devices like phones and tablets, where we have
> > > a proprietary primary boot loader). But if you have suggestions for
> > > better names, let me know. :)
> > 
> > Sure, if any Exynos is supported, then exynos-mobile is fine.
> > 
> > > > > +U-Boot is packed with multiple FDTs since it targets multiple
> > > > > boards. The
> > > > > +appropriate FDT is selected during boot. Additionally, a DTB is
> > > > > also required
> > > > > +for embedding in the Android boot image. The previous bootloader
> > > > > can apply
> > > > > +useful overlays on it. Both DTBs are consulted for figuring out the
> > > > > memory
> > > > > +layout.
> > 
> > Not all Exynos'es have bootloaders that support boot images, and among
> > the ones that do, not all support dtbs. Please move to 7870 specific
> > section and/or make the paragraph more generic if it should support
> > any Exynos.
> > 
> > > >
> > > > > +Installation
> > > > > +------------
> > > > > +Building
> > > > > +^^^^^^^^
> > > > > +To buiid U-Boot, run the following commands
> > > >
> > > > Typo, buiid -> build
> > > >
> > > > > +.. prompt:: bash $
> > > > > +
> > > > > +	make CROSS_COMPILE=aarch64-linux-gnu- O=.output
> > > > > exynos-mobile_defconfig
> > > > > +	make CROSS_COMPILE=aarch64-linux-gnu- O=.output -j$(nproc)
> > > >
> > > > I think CROSS_COMPILE=aarch64-linux-gnu- can be dropped from the
> > > > example, or are only
> > > > aarch64 devices supported?
> > > 
> > > Plans were for aarch64. But if its possible to add armv7 support, then
> > > that would be great! Is multiple arch-es for the same board possible?
> > 
> > Probably not, but not all Exynos'es are armv8, so if instructions
> > should be for any Exynos then I think it is best to leave $arch out of
> > the commands.
> 
> I get that, but the board file even uses a lot of armv8 specific stuff
> (#include <asm/armv8/mmu.h>) and I don't have any armv7 devices to
> implement or test. So I am kind of unsure as of what to do here.

Yeah, it would be up to the people dealing with armv7 devices, like
myself, to implement and test it I think. Probably cleanest way would
to have two boards, maybe with some functions/parts moved to common dir.

> I may as well add a paragraph for cross-compilers, but then implicitly
> claiming that armv7 is supported while it remains unsupported doesn't
> sit right with me.
> 
> And doing this probably requires two defconfigs - one for armv7, another
> for armv8. There's quite a bit of work required for separation, and I
> am not sure anymore if I should continue to brand it as "all exynos"
> (though I'd love to have it that way), or upstream in this condition
> and figure out later.

To start with I think scope should be clarified in docs. If only armv8
exynos socs (with or without QCDT dt.img) will be supported, then
please mention it in intro section, and maybe change title from
`Samsung Exynos Generic Boards` to `Samsung Exynos Generic Arm64
Boards` or something. exynos-mobile as board name should be fine.

If armv7 support is added in future somehow then we can always revise
docs.

Best regards,
Henrik Grimler

> > 
> > Best regards,
> > Henrik Grimler
> > 
> > > > > +If succcessful, the U-Boot binary will be present in
> > > > > ``.output/u-boot.bin``.
> > > >
> > > > Typo, succcessful -> successful.
> > > >
> > > > > +
> > > > > +Preparation
> > > > > +^^^^^^^^^^^
> > > > > +The U-Boot binary is not flashable as-is, it needs to be
> > > > > encapsulated in an
> > > > > +Android boot image. Since it supports multiple boards, and devices
> > > > > have
> > > > > +different requirements (thanks to the lack of standards), this step
> > > > > varies
> > > >
> > > > I think `(thanks to the lack of standards)` is a bit opinionated, and
> > > > does not really add anything here, could you please remove it?
> > > 
> > > I agree. Will remove it.
> > > 
> > > >
> > > > > +depending on your target.
> > > > > +
> > > > > +Exynos 7870 Boards
> > > > > +""""""""""""""""""
> > > > > +Create the following devicetree (named ``stub.dts``)
> > > > > +
> > > > > +.. code-block:: devicetree
> > > > > +
> > > > > +	/dts-v1/;
> > > > > +
> > > > > +	/ {
> > > > > +		compatible = "samsung,exynos7870";
> > > > > +		#address-cells = <2>;
> > > > > +		#size-cells = <1>;
> > > > > +
> > > > > +		model_info-chip = <7870>;
> > > > > +		model_info-hw_rev = <0>;
> > > > > +		model_info-hw_rev_end = <255>;
> > > > > +
> > > > > +		chosen {
> > > > > +		};
> > > > > +
> > > > > +		memory@80000000 {
> > > > > +			device_type = "memory";
> > > > > +			reg = <0x0 0x80000000 0x0>;
> > > > > +		};
> > > > > +
> > > > > +		memory@100000000 {
> > > > > +			device_type = "memory";
> > > > > +			reg = <0x1 0x00000000 0x0>;
> > > > > +		};
> > > > > +	};
> > > > > +
> > > > > +The chosen node and memory ranges are populated by S-BOOT.
> > > > > +
> > > > > +Compile it to a devicetree blob, then use ``dtbTool-exynos`` in
> > > > > order to pack it
> > > > > +in the QCDT format [1]_, using the following commands:
> > > > > +
> > > > > +.. prompt:: bash $
> > > > > +
> > > > > +	dtc -I dts -O dtb -o stub.dtb stub.dts
> > > > > +	dtbTool-exynos -o stub.dt.img stub.dtb
> > > > > +
> > > > > +Finally, use mkbootimg by osm0sis [2]_ to generate the boot image:
> > > > > +
> > > > > +.. prompt:: bash $
> > > > > +
> > > > > +	mkbootimg -o u-boot.img \
> > > > > +		--kernel	.output/u-boot.bin \
> > > > > +		--dt		stub.dt.img
> > > > > +
> > > > > +Offsets are not provided to ``mkbootimg`` as S-BOOT ignores them.
> > > > > +
> > > > > +Flashing
> > > > > +^^^^^^^^
> > > > > +If flashing for the first time, it must be done via Samsung's
> > > > > Download (Odin)
> > > > > +mode. Heimdall can be used for flashing, like so:
> > > >
> > > > Maybe it would be useful to link to Heimdall in references as well.
> > > >
> > > > Best regards,
> > > > Henrik Grimler
> > > >
> > > > > +.. prompt:: bash $
> > > > > +
> > > > > +	heimdall flash --BOOT u-boot.img
> > > > > +
> > > > > +However, if U-Boot is already installed, you may also use its
> > > > > fastboot interface
> > > > > +for flashing. Boot into the boot menu by holding the volume down
> > > > > key. Enable
> > > > > +fastboot mode from there, connect the device to your host, then run:
> > > > > +
> > > > > +.. prompt:: bash $
> > > > > +
> > > > > +	fastboot flash boot u-boot.img
> > > > > +
> > > > > +To flash an OS image in internal storage, fastboot is a reliable
> > > > > option.
> > > > > +
> > > > > +References
> > > > > +----------
> > > > > +.. [1] https://wiki.postmarketos.org/wiki/QCDT
> > > > > +.. [2] https://github.com/osm0sis/mkbootimg
> > > > > diff --git a/doc/board/samsung/index.rst b/doc/board/samsung/index.rst
> > > > > index 1b92c9518a57df102c2b64ff934b460548ce3d53..1fbe88130c049e1a33d22ae9230fb60ddccea131
> > > > > 100644
> > > > > --- a/doc/board/samsung/index.rst
> > > > > +++ b/doc/board/samsung/index.rst
> > > > > @@ -8,4 +8,5 @@ Samsung
> > > > >
> > > > >     axy17lte
> > > > >     e850-96
> > > > > +   exynos-mobile
> > > > >     n1
> > > > > diff --git a/include/configs/exynos-mobile.h
> > > > > b/include/configs/exynos-mobile.h
> > > > > new file mode 100644
> > > > > index 0000000000000000000000000000000000000000..862db5779ef4c9ff7f53bef78d7cee5107b7226e
> > > > > --- /dev/null
> > > > > +++ b/include/configs/exynos-mobile.h
> > > > > @@ -0,0 +1,14 @@
> > > > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > > > +/*
> > > > > + * Samsung Exynos Generic Board Configuration (for mobile devices)
> > > > > + *
> > > > > + * Copyright (C) 2025 Kaustabh Chakraborty <kauschluss@disroot.org>
> > > > > + */
> > > > > +
> > > > > +#ifndef __CONFIG_EXYNOS_MOBILE_H
> > > > > +#define __CONFIG_EXYNOS_MOBILE_H
> > > > > +
> > > > > +#define CPU_RELEASE_ADDR	secondary_boot_addr
> > > > > +#define CFG_SYS_BAUDRATE_TABLE	{9600, 115200}
> > > > > +
> > > > > +#endif /* __CONFIG_EXYNOS_MOBILE_H */
> > > > >
> > > > > ---
> > > > > base-commit: 582a04763aa80738c1c8ac60c47d1a5159a42833
> > > > > change-id: 20251017-board-exynos-mobile-7c7d43832693
> > > > >
> > > > > Best regards,
> > > > > --
> > > > > Kaustabh Chakraborty <kauschluss@disroot.org>
> > > > >