[PATCH 1/2] board: stemmy: Parse atags to get available memory

[PATCH 1/2] board: stemmy: Parse atags to get available memory

[Stephan Gerhold]

At the moment the "stemmy" board attempts to detect the RAM size with
a simple memory test (get_ram_size()). Unfortunately, this does not work
correctly for devices with 768 MiB RAM (e.g. Samsung Galaxy Ace 2
(GT-I8160), "codina"). Reading/writing memory after the 768 MiB RAM
succeeds but actually overwrites some earlier parts of the memory.

For U-Boot this does not result in any major problems, but on Linux
this will eventually lead to strange crashes because of the memory
corruption.

Since the "stemmy" U-Boot port is designed to be chainloaded from
the original Samsung bootloader, the most reliable way to get the
available amount of RAM is to look at the ATAGS passed by the Samsung
bootloader. Fortunately, the header used to generate ATAGS in U-Boot
(asm/setup.h) can also be easily used to parse them.

Also clarify and simplify stemmy.h a bit to make it more clear where
some of the magic values in there are actually coming from.

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
---

 arch/arm/mach-u8500/Kconfig |  1 +
 board/ste/stemmy/README     |  1 +
 board/ste/stemmy/stemmy.c   | 62 ++++++++++++++++++++++++++++++++++++-
 configs/stemmy_defconfig    |  2 +-
 include/configs/stemmy.h    | 23 ++++++--------
 5 files changed, 74 insertions(+), 15 deletions(-)

diff --git a/arch/arm/mach-u8500/Kconfig b/arch/arm/mach-u8500/Kconfig
index 7478deb25f..372fbeb80f 100644
--- a/arch/arm/mach-u8500/Kconfig
+++ b/arch/arm/mach-u8500/Kconfig
@@ -15,6 +15,7 @@ config TARGET_STEMMY
 	      - Samsung Galaxy S III mini (GT-I8190)	"golden"
 	      - Samsung Galaxy S Advance (GT-I9070)	"janice"
 	      - Samsung Galaxy Xcover 2 (GT-S7710)	"skomer"
+	      - Samsung Galaxy Ace 2 (GT-I8160)		"codina"
 
 	  and likely others as well (untested).
 
diff --git a/board/ste/stemmy/README b/board/ste/stemmy/README
index 81f72426f2..1b83b833c0 100644
--- a/board/ste/stemmy/README
+++ b/board/ste/stemmy/README
@@ -7,6 +7,7 @@ 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"
+	- Samsung Galaxy Ace 2 (GT-I8160)	"codina"
 
 and likely others as well (untested).
 
diff --git a/board/ste/stemmy/stemmy.c b/board/ste/stemmy/stemmy.c
index b9b2a6fddc..9e6c8e208e 100644
--- a/board/ste/stemmy/stemmy.c
+++ b/board/ste/stemmy/stemmy.c
@@ -4,17 +4,77 @@
  */
 #include <common.h>
 #include <init.h>
+#include <log.h>
 #include <asm/global_data.h>
+#include <asm/setup.h>
+#include <asm/system.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
+/* Parse atags provided by Samsung bootloader to get available memory */
+static ulong fw_mach __section(".data");
+static ulong fw_atags __section(".data");
+
+void save_boot_params(ulong r0, ulong r1, ulong r2, ulong r3)
+{
+	fw_mach = r1;
+	fw_atags = r2;
+	save_boot_params_ret();
+}
+
+static const struct tag *fw_atags_get(void)
+{
+	const struct tag *tags = (const struct tag *)fw_atags;
+
+	if (tags->hdr.tag != ATAG_CORE) {
+		log_err("Invalid atags: tag 0x%x at %p\n", tags->hdr.tag, tags);
+		return NULL;
+	}
+
+	return tags;
+}
+
 int dram_init(void)
 {
-	gd->ram_size = get_ram_size(CONFIG_SYS_SDRAM_BASE, CONFIG_SYS_SDRAM_SIZE);
+	const struct tag *t, *tags = fw_atags_get();
+
+	if (!tags)
+		return -EINVAL;
+
+	for_each_tag(t, tags) {
+		if (t->hdr.tag != ATAG_MEM)
+			continue;
+
+		debug("Memory: %#x-%#x (size %#x)\n", t->u.mem.start,
+		      t->u.mem.start + t->u.mem.size, t->u.mem.size);
+		gd->ram_size += t->u.mem.size;
+	}
+	return 0;
+}
+
+int dram_init_banksize(void)
+{
+	const struct tag *t, *tags = fw_atags_get();
+	unsigned int bank = 0;
+
+	if (!tags)
+		return -EINVAL;
+
+	for_each_tag(t, tags) {
+		if (t->hdr.tag != ATAG_MEM)
+			continue;
+
+		gd->bd->bi_dram[bank].start = t->u.mem.start;
+		gd->bd->bi_dram[bank].size = t->u.mem.size;
+		if (++bank == CONFIG_NR_DRAM_BANKS)
+			break;
+	}
 	return 0;
 }
 
 int board_init(void)
 {
+	gd->bd->bi_arch_number = fw_mach;
+	gd->bd->bi_boot_params = fw_atags;
 	return 0;
 }
diff --git a/configs/stemmy_defconfig b/configs/stemmy_defconfig
index 79c05acc6a..f31960b814 100644
--- a/configs/stemmy_defconfig
+++ b/configs/stemmy_defconfig
@@ -1,7 +1,7 @@
 CONFIG_ARM=y
 CONFIG_ARCH_U8500=y
 CONFIG_SYS_TEXT_BASE=0x100000
-CONFIG_NR_DRAM_BANKS=1
+CONFIG_NR_DRAM_BANKS=2
 CONFIG_DEFAULT_DEVICE_TREE="ste-ux500-samsung-stemmy"
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_HUSH_PARSER=y
diff --git a/include/configs/stemmy.h b/include/configs/stemmy.h
index 922eec43ee..c446b09270 100644
--- a/include/configs/stemmy.h
+++ b/include/configs/stemmy.h
@@ -7,23 +7,20 @@
 
 #include <linux/sizes.h>
 
-#define CONFIG_SKIP_LOWLEVEL_INIT	/* Loaded by another bootloader */
-#define CONFIG_SYS_MALLOC_LEN		SZ_2M
+/*
+ * The "stemmy" U-Boot port is designed to be chainloaded by the Samsung
+ * bootloader on devices based on ST-Ericsson Ux500. Therefore, we skip most
+ * low-level initialization and rely on configuration provided by the Samsung
+ * bootloader. New images are loaded at the same address for compatibility.
+ */
+#define CONFIG_SKIP_LOWLEVEL_INIT
+#define CONFIG_SYS_INIT_SP_ADDR		CONFIG_SYS_TEXT_BASE
+#define CONFIG_SYS_LOAD_ADDR		CONFIG_SYS_TEXT_BASE
 
-/* 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
+#define CONFIG_SYS_MALLOC_LEN		SZ_2M
 
 /* 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
-- 
2.32.0

[PATCH 2/2] board: stemmy: Copy atags for booting downstream/vendor kernel

[Stephan Gerhold]

The U-Boot "stemmy" board is mainly intended to simplify booting
mainline Linux on various smartphones from Samsung based on ST-Ericsson
Ux500. While the mainline kernel is working great, there are still some
features missing there. In particular, it is currently not possible to
charge the battery when using the mainline kernel.

This means that it is still necessary to boot the downstream/vendor
kernel from Samsung sometimes to charge the device. That kernel is
ancient, still uses board files + ATAGS instead of device trees and
relies on a strange very long kernel command line hardcoded in the
Samsung bootloader.

Actually, since mainline is booted with device trees there is a very
simple way to make the old downstream kernel work as well: We can
simply take most of the ATAGS passed to U-Boot from the Samsung
bootloader and copy them as-is when booting a kernel without device
tree. That way the long command line and other needed ATAGS are copied
as-is without having to bother with them.

The only exception is the ATAG_INITRD - since the initrd is loaded
by U-Boot, the atag for that should be generated in U-Boot so it points
to the correct address. All other ATAGS are copied as-is and not
generated in U-Boot.

Also use the chance and provide a serial# for U-Boot by parsing the
ATAG_SERIAL that is also passed by the Samsung bootloader.

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
---

 arch/arm/mach-u8500/Kconfig |  1 +
 board/ste/stemmy/stemmy.c   | 87 +++++++++++++++++++++++++++++++++++++
 include/configs/stemmy.h    |  3 ++
 3 files changed, 91 insertions(+)

diff --git a/arch/arm/mach-u8500/Kconfig b/arch/arm/mach-u8500/Kconfig
index 372fbeb80f..db7a29a54c 100644
--- a/arch/arm/mach-u8500/Kconfig
+++ b/arch/arm/mach-u8500/Kconfig
@@ -8,6 +8,7 @@ choice
 
 config TARGET_STEMMY
 	bool "Samsung (stemmy) board"
+	select MISC_INIT_R
 	help
 	  The Samsung "stemmy" board supports Samsung smartphones released with
 	  the ST-Ericsson NovaThor U8500 SoC, e.g.
diff --git a/board/ste/stemmy/stemmy.c b/board/ste/stemmy/stemmy.c
index 9e6c8e208e..5f1150c0c7 100644
--- a/board/ste/stemmy/stemmy.c
+++ b/board/ste/stemmy/stemmy.c
@@ -3,8 +3,10 @@
  * Copyright (C) 2019 Stephan Gerhold <stephan@gerhold.net>
  */
 #include <common.h>
+#include <env.h>
 #include <init.h>
 #include <log.h>
+#include <stdlib.h>
 #include <asm/global_data.h>
 #include <asm/setup.h>
 #include <asm/system.h>
@@ -15,6 +17,9 @@ DECLARE_GLOBAL_DATA_PTR;
 static ulong fw_mach __section(".data");
 static ulong fw_atags __section(".data");
 
+static const struct tag *fw_atags_copy;
+static uint fw_atags_size;
+
 void save_boot_params(ulong r0, ulong r1, ulong r2, ulong r3)
 {
 	fw_mach = r1;
@@ -78,3 +83,85 @@ int board_init(void)
 	gd->bd->bi_boot_params = fw_atags;
 	return 0;
 }
+
+static void parse_serial(const struct tag_serialnr *serialnr)
+{
+	char serial[17];
+
+	if (env_get("serial#"))
+		return;
+
+	sprintf(serial, "%08x%08x", serialnr->high, serialnr->low);
+	env_set("serial#", serial);
+}
+
+/*
+ * The downstream/vendor kernel (provided by Samsung) uses ATAGS for booting.
+ * It also requires an extremely long cmdline provided by the primary bootloader
+ * that is not suitable for booting mainline.
+ *
+ * Since downstream is the only user of ATAGS, we emulate the behavior of the
+ * Samsung bootloader by generating only the initrd atag in U-Boot, and copying
+ * all other ATAGS as-is from the primary bootloader.
+ */
+static inline bool skip_atag(u32 tag)
+{
+	return (tag == ATAG_NONE || tag == ATAG_CORE ||
+		tag == ATAG_INITRD || tag == ATAG_INITRD2);
+}
+
+static void copy_atags(const struct tag *tags)
+{
+	const struct tag *t;
+	struct tag *copy;
+
+	if (!tags)
+		return;
+
+	/* Calculate necessary size for tags we want to copy */
+	for_each_tag(t, tags) {
+		if (skip_atag(t->hdr.tag))
+			continue;
+
+		if (t->hdr.tag == ATAG_SERIAL)
+			parse_serial(&t->u.serialnr);
+
+		fw_atags_size += t->hdr.size * sizeof(u32);
+	}
+
+	if (!fw_atags_size)
+		return;  /* No tags to copy */
+
+	copy = malloc(fw_atags_size);
+	if (!copy)
+		return;
+	fw_atags_copy = copy;
+
+	/* Copy tags */
+	for_each_tag(t, tags) {
+		if (skip_atag(t->hdr.tag))
+			continue;
+
+		memcpy(copy, t, t->hdr.size * sizeof(u32));
+		copy = tag_next(copy);
+	}
+}
+
+int misc_init_r(void)
+{
+	copy_atags(fw_atags_get());
+	return 0;
+}
+
+void setup_board_tags(struct tag **in_params)
+{
+	if (!fw_atags_copy)
+		return;
+
+	/*
+	 * fw_atags_copy contains only full "struct tag" (plus data)
+	 * so copying it bytewise here should be fine.
+	 */
+	memcpy(*in_params, fw_atags_copy, fw_atags_size);
+	*(u8 **)in_params += fw_atags_size;
+}
diff --git a/include/configs/stemmy.h b/include/configs/stemmy.h
index c446b09270..b94ef91c2b 100644
--- a/include/configs/stemmy.h
+++ b/include/configs/stemmy.h
@@ -23,4 +23,7 @@
 #define CONFIG_SYS_L2_PL310
 #define CONFIG_SYS_PL310_BASE		0xa0412000
 
+/* Generate initrd atag for downstream kernel (others are copied in stemmy.c) */
+#define CONFIG_INITRD_TAG
+
 #endif
-- 
2.32.0

Re: [PATCH 1/2] board: stemmy: Parse atags to get available memory

[Linus Walleij]

On Wed, Jul 7, 2021 at 12:59 PM Stephan Gerhold <stephan@gerhold.net> wrote:

> At the moment the "stemmy" board attempts to detect the RAM size with
> a simple memory test (get_ram_size()). Unfortunately, this does not work
> correctly for devices with 768 MiB RAM (e.g. Samsung Galaxy Ace 2
> (GT-I8160), "codina"). Reading/writing memory after the 768 MiB RAM
> succeeds but actually overwrites some earlier parts of the memory.
>
> For U-Boot this does not result in any major problems, but on Linux
> this will eventually lead to strange crashes because of the memory
> corruption.
>
> Since the "stemmy" U-Boot port is designed to be chainloaded from
> the original Samsung bootloader, the most reliable way to get the
> available amount of RAM is to look at the ATAGS passed by the Samsung
> bootloader. Fortunately, the header used to generate ATAGS in U-Boot
> (asm/setup.h) can also be easily used to parse them.
>
> Also clarify and simplify stemmy.h a bit to make it more clear where
> some of the magic values in there are actually coming from.
>
> Signed-off-by: Stephan Gerhold <stephan@gerhold.net>

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

>               - Samsung Galaxy S III mini (GT-I8190)    "golden"
>               - Samsung Galaxy S Advance (GT-I9070)     "janice"
>               - Samsung Galaxy Xcover 2 (GT-S7710)      "skomer"
> +             - Samsung Galaxy Ace 2 (GT-I8160)         "codina"

I have also used Stemmy U-boot successfully on
Samsung Galaxy Beam (GT-I8530) "gavini"
Samsung Galaxy Amp (SGH-I407) "kyle"

Yours,
Linus Walleij

Re: [PATCH 2/2] board: stemmy: Copy atags for booting downstream/vendor kernel

[Linus Walleij]

On Wed, Jul 7, 2021 at 12:59 PM Stephan Gerhold <stephan@gerhold.net> wrote:

> The U-Boot "stemmy" board is mainly intended to simplify booting
> mainline Linux on various smartphones from Samsung based on ST-Ericsson
> Ux500. While the mainline kernel is working great, there are still some
> features missing there. In particular, it is currently not possible to
> charge the battery when using the mainline kernel.
>
> This means that it is still necessary to boot the downstream/vendor
> kernel from Samsung sometimes to charge the device. That kernel is
> ancient, still uses board files + ATAGS instead of device trees and
> relies on a strange very long kernel command line hardcoded in the
> Samsung bootloader.
>
> Actually, since mainline is booted with device trees there is a very
> simple way to make the old downstream kernel work as well: We can
> simply take most of the ATAGS passed to U-Boot from the Samsung
> bootloader and copy them as-is when booting a kernel without device
> tree. That way the long command line and other needed ATAGS are copied
> as-is without having to bother with them.
>
> The only exception is the ATAG_INITRD - since the initrd is loaded
> by U-Boot, the atag for that should be generated in U-Boot so it points
> to the correct address. All other ATAGS are copied as-is and not
> generated in U-Boot.
>
> Also use the chance and provide a serial# for U-Boot by parsing the
> ATAG_SERIAL that is also passed by the Samsung bootloader.
>
> Signed-off-by: Stephan Gerhold <stephan@gerhold.net>

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

Yours,
Linus Walleij

Re: [PATCH 1/2] board: stemmy: Parse atags to get available memory

[Tom Rini]

[-- Attachment #1: Type: text/plain, Size: 1235 bytes --]

On Wed, Jul 07, 2021 at 12:58:54PM +0200, Stephan Gerhold wrote:

> At the moment the "stemmy" board attempts to detect the RAM size with
> a simple memory test (get_ram_size()). Unfortunately, this does not work
> correctly for devices with 768 MiB RAM (e.g. Samsung Galaxy Ace 2
> (GT-I8160), "codina"). Reading/writing memory after the 768 MiB RAM
> succeeds but actually overwrites some earlier parts of the memory.
> 
> For U-Boot this does not result in any major problems, but on Linux
> this will eventually lead to strange crashes because of the memory
> corruption.
> 
> Since the "stemmy" U-Boot port is designed to be chainloaded from
> the original Samsung bootloader, the most reliable way to get the
> available amount of RAM is to look at the ATAGS passed by the Samsung
> bootloader. Fortunately, the header used to generate ATAGS in U-Boot
> (asm/setup.h) can also be easily used to parse them.
> 
> Also clarify and simplify stemmy.h a bit to make it more clear where
> some of the magic values in there are actually coming from.
> 
> Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Applied to u-boot/master, thanks!

-- 
Tom

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Re: [PATCH 2/2] board: stemmy: Copy atags for booting downstream/vendor kernel

[Tom Rini]

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On Wed, Jul 07, 2021 at 12:58:55PM +0200, Stephan Gerhold wrote:

> The U-Boot "stemmy" board is mainly intended to simplify booting
> mainline Linux on various smartphones from Samsung based on ST-Ericsson
> Ux500. While the mainline kernel is working great, there are still some
> features missing there. In particular, it is currently not possible to
> charge the battery when using the mainline kernel.
> 
> This means that it is still necessary to boot the downstream/vendor
> kernel from Samsung sometimes to charge the device. That kernel is
> ancient, still uses board files + ATAGS instead of device trees and
> relies on a strange very long kernel command line hardcoded in the
> Samsung bootloader.
> 
> Actually, since mainline is booted with device trees there is a very
> simple way to make the old downstream kernel work as well: We can
> simply take most of the ATAGS passed to U-Boot from the Samsung
> bootloader and copy them as-is when booting a kernel without device
> tree. That way the long command line and other needed ATAGS are copied
> as-is without having to bother with them.
> 
> The only exception is the ATAG_INITRD - since the initrd is loaded
> by U-Boot, the atag for that should be generated in U-Boot so it points
> to the correct address. All other ATAGS are copied as-is and not
> generated in U-Boot.
> 
> Also use the chance and provide a serial# for U-Boot by parsing the
> ATAG_SERIAL that is also passed by the Samsung bootloader.
> 
> Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Applied to u-boot/master, thanks!

-- 
Tom

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