[U-Boot] [PATCH V3 4/4] arm: mx5: Avoid hardcoding memory sizes on M53EVK

[Marek Vasut]

The DRAM size can be easily detected at runtime on i.MX53. Implement
such detection on M53EVK and adjust the rest of the macros accordingly
to use the detected values.

An important thing to note here is that we had to override the function
for trimming the effective DRAM address, get_effective_memsize(). That
is because the function uses CONFIG_MAX_MEM_MAPPED as the upper bound of
the available DRAM and we don't have gd->bd->bi_dram[0].size set up at
the time the function is called, thus we cannot put this into the macro
CONFIG_MAX_MEM_MAPPED . Instead, we use custom override where we use the
size of the first DRAM block which we just detected.

Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Fabio Estevam <fabio.estevam at freescale.com>
Cc: Stefano Babic <sbabic at denx.de>
Cc: Wolfgang Denk <wd at denx.de>
---
 board/denx/m53evk/m53evk.c | 31 ++++++++++++++++++++++++-------
 include/configs/m53evk.h   |  8 +++-----
 2 files changed, 27 insertions(+), 12 deletions(-)

V2: Use linux/sizes.h instead of asm/sizes.h
V3: - Drop use of sizes.h completely
    - Add beefy comment as to why we override get_effective_memsize()
    - Drop CONFIG_VERY_BIG_RAM and CONFIG_MAX_MEM_MAPPED as we no longer
      need it if we override get_effective_memsize()

diff --git a/board/denx/m53evk/m53evk.c b/board/denx/m53evk/m53evk.c
index 0f71a16..74f9501 100644
--- a/board/denx/m53evk/m53evk.c
+++ b/board/denx/m53evk/m53evk.c
@@ -31,24 +31,41 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-int dram_init(void)
+static uint32_t mx53_dram_size[2];
+
+phys_size_t get_effective_memsize(void)
 {
-	u32 size1, size2;
+	/*
+	 * WARNING: We must override get_effective_memsize() function here
+	 * to report only the size of the first DRAM bank. This is to make
+	 * U-Boot relocator place U-Boot into valid memory, that is, at the
+	 * end of the first DRAM bank. If we did not override this function
+	 * like so, U-Boot would be placed at the address of the first DRAM
+	 * bank + total DRAM size - sizeof(uboot), which in the setup where
+	 * each DRAM bank contains 512MiB of DRAM would result in placing
+	 * U-Boot into invalid memory area close to the end of the first
+	 * DRAM bank.
+	 */
+	return mx53_dram_size[0];
+}
 
-	size1 = get_ram_size((void *)PHYS_SDRAM_1, PHYS_SDRAM_1_SIZE);
-	size2 = get_ram_size((void *)PHYS_SDRAM_2, PHYS_SDRAM_2_SIZE);
+int dram_init(void)
+{
+	mx53_dram_size[0] = get_ram_size((void *)PHYS_SDRAM_1, 1 << 30);
+	mx53_dram_size[1] = get_ram_size((void *)PHYS_SDRAM_2, 1 << 30);
 
-	gd->ram_size = size1 + size2;
+	gd->ram_size = mx53_dram_size[0] + mx53_dram_size[1];
 
 	return 0;
 }
+
 void dram_init_banksize(void)
 {
 	gd->bd->bi_dram[0].start = PHYS_SDRAM_1;
-	gd->bd->bi_dram[0].size = PHYS_SDRAM_1_SIZE;
+	gd->bd->bi_dram[0].size = mx53_dram_size[0];
 
 	gd->bd->bi_dram[1].start = PHYS_SDRAM_2;
-	gd->bd->bi_dram[1].size = PHYS_SDRAM_2_SIZE;
+	gd->bd->bi_dram[1].size = mx53_dram_size[1];
 }
 
 static void setup_iomux_uart(void)
diff --git a/include/configs/m53evk.h b/include/configs/m53evk.h
index 6f8872e..f401470 100644
--- a/include/configs/m53evk.h
+++ b/include/configs/m53evk.h
@@ -46,15 +46,13 @@
  */
 #define CONFIG_NR_DRAM_BANKS		2
 #define PHYS_SDRAM_1			CSD0_BASE_ADDR
-#define PHYS_SDRAM_1_SIZE		(512 * 1024 * 1024)
+#define PHYS_SDRAM_1_SIZE		(gd->bd->bi_dram[0].size)
 #define PHYS_SDRAM_2			CSD1_BASE_ADDR
-#define PHYS_SDRAM_2_SIZE		(512 * 1024 * 1024)
-#define PHYS_SDRAM_SIZE			(PHYS_SDRAM_1_SIZE + PHYS_SDRAM_2_SIZE)
+#define PHYS_SDRAM_2_SIZE		(gd->bd->bi_dram[1].size)
+#define PHYS_SDRAM_SIZE			(gd->ram_size)
 #define CONFIG_SYS_MALLOC_LEN		(10 * 1024 * 1024)
 #define CONFIG_SYS_MEMTEST_START	0x70000000
 #define CONFIG_SYS_MEMTEST_END		0x8ff00000
-#define CONFIG_VERY_BIG_RAM
-#define CONFIG_MAX_MEM_MAPPED		PHYS_SDRAM_1_SIZE
 
 #define CONFIG_SYS_SDRAM_BASE		(PHYS_SDRAM_1)
 #define CONFIG_SYS_INIT_RAM_ADDR	(IRAM_BASE_ADDR)
-- 
1.9.0