ARM: imx: imx8m: Fix board_get_usable_ram_top()

The 4 GiB boundary is at 0xffffffff+1 , not at 0x80000000, fix this.

The PHYS_SDRAM of i.MX8M is at 0x40000000 , so to restrict ram_top
below 4 GiB, the ram_top has to be set to 0xffffffff as it is not
an offset from the start of PHYS_SDRAM, but rather a physical address
marking the topmost allowed DRAM address.

Fixes: e27bddff4b9 ("imx8m: Restrict usable memory to space below 4G boundary")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <festevam@denx.de>
Cc: Frieder Schrempf <frieder.schrempf@kontron.de>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Reviewed-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.de>

diff --git a/arch/arm/mach-imx/imx8m/soc.c b/arch/arm/mach-imx/imx8m/soc.c
index 8171631..e7fe7c2 100644 (file)
--- a/arch/arm/mach-imx/imx8m/soc.c
+++ b/arch/arm/mach-imx/imx8m/soc.c
@@ -331,7 +331,7 @@ phys_size_t get_effective_memsize(void)
 
 ulong board_get_usable_ram_top(ulong total_size)
 {
-       ulong top_addr = PHYS_SDRAM + gd->ram_size;
+       ulong top_addr;
 
        /*
         * Some IPs have their accessible address space restricted by
@@ -339,8 +339,7 @@ ulong board_get_usable_ram_top(ulong total_size)
         * space below the 4G address boundary (which is 3GiB big),
         * even when the effective available memory is bigger.
         */
-       if (top_addr > 0x80000000)
-               top_addr = 0x80000000;
+       top_addr = clamp_val((u64)PHYS_SDRAM + gd->ram_size, 0, 0xffffffff);
 
        /*
         * rom_pointer[0] stores the TEE memory start address.