From: David Lechner <dlechner@baylibre.com>
Date: Mon, 15 Jun 2026 19:23:37 +0000 (-0500)
Subject: arm: mediatek: mt8195: fix gd->bd->bi_dram[0].size
X-Git-Tag: v2026.07~13^2~1
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=ec457f7cfde59a2122297a7a217c88f02acc63a5;p=thirdparty%2Fu-boot.git

arm: mediatek: mt8195: fix gd->bd->bi_dram[0].size

Use board_get_usable_ram_top() instead of get_effective_memsize() to
set gd->ram_top to something <= 4GiB.

Both board_get_usable_ram_top() and get_effective_memsize() are used to
set gd->ram_top in setup_dest_addr(). However, get_effective_memsize()
also sets gd->bd->bi_dram[0].size in dram_init_banksize(), which is
undesirable.

Prior to commit d83bd9729d75 ("arm: mediatek: mt8195:
drop dram_init_banksize()"), gd->bd->bi_dram[0].size was overridden in
a board-specific dram_init_banksize() implementation. When that was
removed get_effective_memsize() set gd->bd->bi_dram[0].size to the wrong
value because of get_effective_memsize() being overridden in commit
af4cba9a05aa ("arm: mediatek: mt8195: fix gd->ram_top limit")

We can just use board_get_usable_ram_top() now to set gd->ram_top to the
correct value instead. This is possible now, thanks to
LMB_LIMIT_DMA_BELOW_RAM_TOP being set by default for 64-bit Mediatek
ARM SoCs.

Fixes: d83bd9729d75 ("arm: mediatek: mt8195: drop dram_init_banksize()")
Link: https://patch.msgid.link/20260615-mtk-fix-ram-size-v2-7-f72cfc52ce58@baylibre.com
Signed-off-by: David Lechner <dlechner@baylibre.com>
---

diff --git a/arch/arm/mach-mediatek/mt8195/init.c b/arch/arm/mach-mediatek/mt8195/init.c
index e31d4eec0fb..83cac9d01d6 100644
--- a/arch/arm/mach-mediatek/mt8195/init.c
+++ b/arch/arm/mach-mediatek/mt8195/init.c
@@ -20,13 +20,13 @@ int dram_init(void)
 	return fdtdec_setup_mem_size_base();
 }
 
-phys_size_t get_effective_memsize(void)
+phys_addr_t board_get_usable_ram_top(phys_size_t total_size)
 {
 	/*
 	 * Limit gd->ram_top not exceeding SZ_4G. Because some peripherals like
 	 * MMC requires DMA buffer allocated below SZ_4G.
 	 */
-	return min(SZ_4G - gd->ram_base, gd->ram_size);
+	return min(gd->ram_top, SZ_4G);
 }
 
 int mtk_soc_early_init(void)