From: Jonas Karlman <jonas@kwiboo.se>
Date: Thu, 30 Jan 2025 22:07:12 +0000 (+0000)
Subject: rockchip: sdram: Limit usable ram_top to max 4G
X-Git-Tag: v2025.04-rc3~6^2~7
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=356236126da7877ab115c65f8cb21215443beb2f;p=pandora-u-boot.git

rockchip: sdram: Limit usable ram_top to max 4G

U-Boot only works correctly when it uses RAM below the 4G address
boundary on Rockchip SoCs. Limit usable gd->ram_top to max 4G.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
---

diff --git a/arch/arm/mach-rockchip/sdram.c b/arch/arm/mach-rockchip/sdram.c
index 96a791bda2c..4b8b6b9da7c 100644
--- a/arch/arm/mach-rockchip/sdram.c
+++ b/arch/arm/mach-rockchip/sdram.c
@@ -487,7 +487,8 @@ int dram_init(void)
 
 phys_addr_t board_get_usable_ram_top(phys_size_t total_size)
 {
-	unsigned long top = CFG_SYS_SDRAM_BASE + SDRAM_MAX_SIZE;
+	/* Make sure U-Boot only uses the space below the 4G address boundary */
+	u64 top = min_t(u64, CFG_SYS_SDRAM_BASE + SDRAM_MAX_SIZE, SZ_4G);
 
 	return (gd->ram_top > top) ? top : gd->ram_top;
 }