@@ -205,6 +205,7 @@ int dram_init(void)
return ret;
for (i = 0; i < ARRAY_SIZE(dram_map); i++) {
+ unsigned long max_size;
if (!dram_map[i].size)
break;
@@ -218,6 +219,22 @@ int dram_init(void)
dram_map[i].base)
break;
+ /*
+ * Do not use memory that exceeds 32bit address range. U-Boot
+ * relocates itself to the end of the effectively available RAM.
+ * This could be a problem for DMA engines that do not support
+ * 64bit address (SDMA of SDHCI, UniPhier AV-ether, etc.)
+ */
+ if (dram_map[i].base >= 1ULL << 32)
+ break;
+
+ max_size = (1ULL << 32) - dram_map[i].base;
+
+ if (dram_map[i].size > max_size) {
+ gd->ram_size += max_size;
+ break;
+ }
+
gd->ram_size += dram_map[i].size;
}
LD20 / PXs3 boards are equipped with a large amount of memory beyond the 32 bit address range. U-Boot relocates itself to the end of the available RAM. This is a problem for DMA engines that only support 32 bit physical address, like the SDMA of SDHCI controllers. In fact, U-Boot does not need to run at the very end of RAM. It is rather troublesome for drivers with DMA engines because U-Boot does not have API like dma_set_mask(), so DMA silently fails, making the driver debugging difficult. Hide the memory region that exceeds the 32 bit address range. It can be done by simply carving out gd->ram_size. It would also possible to override get_effective_memsize() or to define CONFIG_MAX_MEM_MAPPED, but dram_init() is a good enough place to do this job. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> --- arch/arm/mach-uniphier/dram_init.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)