Re: [PATCH 1/1] drivers: of: of_reserved_mem: fixup the alignment with CMA setup

From: Marek Szyprowski
Date: Tue Nov 10 2015 - 08:43:15 EST


On 2015-11-10 13:30, Jason Liu wrote:
There is an alignment mismatch issue between the of_reserved_mem and
the CMA setup requirement. The of_reserved_mem will try to get the
alignment value from the DTS and pass it to __memblock_alloc_base to
do the memory block base allocation, but the alignment value specified
in the DTS may not satisfy the CAM setup requirement since CMA setup
required the alignment as the following in the code:

align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);

The sanity check in the function of rmem_cma_setup will fail if the
alignment does not setup correctly and thus CMA will fail to setup.

This patch is to fixup the alignment to meet the CMA setup required.

Signed-off-by: Jason Liu <r64343@xxxxxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Grant Likely <grant.likely@xxxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>

Acked-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>

drivers/of/of_reserved_mem.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 62f467b..9394311 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -124,6 +124,10 @@ static int __init __reserved_mem_alloc_size(unsigned long node,
align = dt_mem_next_cell(dt_root_addr_cells, &prop);
+ /* Need adjust the alignment to satisfy the CMA requirement */
+ if (IS_ENABLED(CONFIG_CMA) && of_flat_dt_is_compatible(node, "shared-dma-pool"))
+ align = max(align, (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
prop = of_get_flat_dt_prop(node, "alloc-ranges", &len);
if (prop) {

Best regards
Marek Szyprowski, PhD
Samsung R&D Institute Poland

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