From b5f2a8c02697c3685ccbbb66495465742ffa0dc1 Mon Sep 17 00:00:00 2001 From: Al Cooper Date: Wed, 6 Aug 2014 16:30:04 -0400 Subject: [PATCH] of: Allow mem_reserve of memory with a base address of zero __reserved_mem_reserve_reg() won't reserve memory if the base address is zero. This change removes the check for a base address of zero and allows it to be reserved. Allowing the first 4K of memory to be reserved will help solve a problem on some ARM systems where the the first 16K of memory is unused and becomes allocable memory. This will prevent this memory from being used for DMA by drivers like the USB OHCI driver which consider a physical address of zero to be illegal. Cc: stable@vger.kernel.org # 3.15+ Signed-off-by: Al Cooper Signed-off-by: Grant Likely --- drivers/of/fdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index f46a24f..79cb831 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -453,7 +453,7 @@ static int __init __reserved_mem_reserve_reg(unsigned long node, base = dt_mem_next_cell(dt_root_addr_cells, &prop); size = dt_mem_next_cell(dt_root_size_cells, &prop); - if (base && size && + if (size && early_init_dt_reserve_memory_arch(base, size, nomap) == 0) pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %ld MiB\n", uname, &base, (unsigned long)size / SZ_1M); -- 2.7.4