[U-Boot] [RFC] odroid: Add support for the ODROID-X board variant

[Siarhei Siamashka]

ODROID-X uses a slightly older revision of the same base board
as the ODROID-X2. But the CPU module in ODROID-X uses an older
1.4GHz revision of Exynos4412 SoC and less RAM (1GiB instead
of 2GiB).

The current U-Boot code deadlocks on ODROID-X when probing the RAM
size via get_ram_size() function. Reducing CONFIG_NR_DRAM_BANKS
from 8 to 4 can fix this problem. But this constant is used in
a lot of places in U-Boot, while SDRAM_BANK_SIZE can be easily
replaced with the code which relies on runtime detection of the
board type. So we change 4 or 8 banks of 256MiB with just one
fake bank of 2GiB or 1GiB. The runtime detection check tries to
read the PRO_ID register in the hope that it might be different
between Exynos4412 and Exynos4412 Prime and enough to detect
the difference between X and X2 board variants.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka at gmail.com>
---

I'm assuming that the X and X2 hardware is nearly identical
and can be supported with a common code in U-Boot, based on
the changelog of PCB revisions:
    http://com.odroid.com/sigong/blog/blog_list.php?bid=132

This is an RFC patch because I don't have an X2 board and can't
test if checking the PRO_ID register is good enough. If it does
not work, then maybe some other method could be tried (probe
the DRAM controller registers?).

Also does the number of DRAM banks have any special meaning on
this platform in U-Boot and Linux (after the proprietary blob
has already initialized the DRAM controller)?

If this approach is wrong, then what would be the best way to
add support for the ODROID-X board?

Thanks.

 board/samsung/common/board.c  | 21 +++++++++++++++++----
 board/samsung/odroid/odroid.c | 14 ++++++++++----
 include/configs/odroid.h      | 10 ++++++----
 3 files changed, 33 insertions(+), 12 deletions(-)

diff --git a/board/samsung/common/board.c b/board/samsung/common/board.c
index d32c75d..ac3ed4c 100644
--- a/board/samsung/common/board.c
+++ b/board/samsung/common/board.c
@@ -94,14 +94,26 @@ int board_init(void)
 	return exynos_init();
 }
 
+static u32 get_sdram_bank_size(void)
+{
+	u32 sdram_bank_size = SDRAM_BANK_SIZE;
+#ifdef CONFIG_BOARD_TYPES
+	if (strcmp(CONFIG_SYS_BOARD, "odroid") == 0 &&
+	    strcmp(get_board_type(), "x") == 0)
+		sdram_bank_size = SDRAM_BANK_SIZE_ODROIDX;
+#endif
+	return sdram_bank_size;
+}
+
 int dram_init(void)
 {
 	unsigned int i;
 	u32 addr;
+	u32 sdram_bank_size = get_sdram_bank_size();
 
 	for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
-		addr = CONFIG_SYS_SDRAM_BASE + (i * SDRAM_BANK_SIZE);
-		gd->ram_size += get_ram_size((long *)addr, SDRAM_BANK_SIZE);
+		addr = CONFIG_SYS_SDRAM_BASE + (i * sdram_bank_size);
+		gd->ram_size += get_ram_size((long *)addr, sdram_bank_size);
 	}
 	return 0;
 }
@@ -110,10 +122,11 @@ void dram_init_banksize(void)
 {
 	unsigned int i;
 	u32 addr, size;
+	u32 sdram_bank_size = get_sdram_bank_size();
 
 	for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
-		addr = CONFIG_SYS_SDRAM_BASE + (i * SDRAM_BANK_SIZE);
-		size = get_ram_size((long *)addr, SDRAM_BANK_SIZE);
+		addr = CONFIG_SYS_SDRAM_BASE + (i * sdram_bank_size);
+		size = get_ram_size((long *)addr, sdram_bank_size);
 
 		gd->bd->bi_dram[i].start = addr;
 		gd->bd->bi_dram[i].size = size;
diff --git a/board/samsung/odroid/odroid.c b/board/samsung/odroid/odroid.c
index 32155f1..e98e3be 100644
--- a/board/samsung/odroid/odroid.c
+++ b/board/samsung/odroid/odroid.c
@@ -30,6 +30,7 @@ DECLARE_GLOBAL_DATA_PTR;
 enum {
 	ODROID_TYPE_U3,
 	ODROID_TYPE_X2,
+	ODROID_TYPE_X,
 	ODROID_TYPES,
 };
 
@@ -56,15 +57,20 @@ void set_board_type(void)
 	sdelay(200000);
 
 	/* Check GPC1 pin2 - LED supplied by XCL205 - X2 only */
-	if (readl(XCL205_STATE_GPIO_DAT) & (1 << XCL205_STATE_GPIO_PIN))
-		gd->board_type = ODROID_TYPE_X2;
-	else
+	if (readl(XCL205_STATE_GPIO_DAT) & (1 << XCL205_STATE_GPIO_PIN)) {
+		/* Check the SoC product information ID */
+		if (readl(EXYNOS4_PRO_ID) == 0xE4412211)
+			gd->board_type = ODROID_TYPE_X;
+		else
+			gd->board_type = ODROID_TYPE_X2;
+	} else {
 		gd->board_type = ODROID_TYPE_U3;
+	}
 }
 
 const char *get_board_type(void)
 {
-	const char *board_type[] = {"u3", "x2"};
+	const char *board_type[] = {"u3", "x2", "x"};
 
 	return board_type[gd->board_type];
 }
diff --git a/include/configs/odroid.h b/include/configs/odroid.h
index 4c85e85..ae1b2b4 100644
--- a/include/configs/odroid.h
+++ b/include/configs/odroid.h
@@ -22,9 +22,10 @@
 
 #define CONFIG_MACH_TYPE	4289
 
-#define CONFIG_NR_DRAM_BANKS	8
+#define CONFIG_NR_DRAM_BANKS	1
 #define CONFIG_SYS_SDRAM_BASE	0x40000000
-#define SDRAM_BANK_SIZE		(256 << 20)	/* 256 MB */
+#define SDRAM_BANK_SIZE		((8 * 256) << 20)	/* 8 * 256 MB */
+#define SDRAM_BANK_SIZE_ODROIDX	((4 * 256) << 20)	/* 4 * 256 MB */
 #define PHYS_SDRAM_1		CONFIG_SYS_SDRAM_BASE
 /* Reserve the last 1 MiB for the secure firmware */
 #define CONFIG_SYS_MEM_TOP_HIDE		(1UL << 20UL)
@@ -75,6 +76,7 @@
 	"uInitrd fat 0 1;" \
 	"exynos4412-odroidu3.dtb fat 0 1;" \
 	"exynos4412-odroidx2.dtb fat 0 1;" \
+	"exynos4412-odroidx.dtb fat 0 1;" \
 	""PARTS_BOOT" part 0 1;" \
 	""PARTS_ROOT" part 0 2\0" \
 
@@ -209,8 +211,8 @@
 #define CONFIG_USB_ETHER_SMSC95XX
 
 /*
- * Supported Odroid boards: X3, U3
- * TODO: Add Odroid X support
+ * Supported Odroid boards: X, X2, U3
+ * TODO: Add Odroid U2 support
  */
 #define CONFIG_MISC_COMMON
 #define CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
-- 
2.4.9