cma: Add support for memory limits
Currently, when dynamically placing regions CMA will allow the memory
to be placed anywhere, including highmem. Due to system restrictions,
regions may need to be placed in a smaller range. Add support to
devicetree to allow these regions to have an upper bound on where they
will be placed.
Change-Id: Ib4ae194cbb6389e1091e7e04cfd331e9ab67ad05
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
[skhiani@codeaurora.org: Resolve merge conflicts]
Signed-off-by: Susheel Khiani <skhiani@codeaurora.org>
diff --git a/Documentation/devicetree/bindings/memory.txt b/Documentation/devicetree/bindings/memory.txt
index e98ee05..32f6a24 100644
--- a/Documentation/devicetree/bindings/memory.txt
+++ b/Documentation/devicetree/bindings/memory.txt
@@ -36,6 +36,7 @@
reg = <(baseaddr) (size)>;
(linux,contiguous-region);
(linux,default-contiguous-region);
+ (linux,memory-limit);
label = (unique_name);
};
@@ -48,6 +49,11 @@
linux,default-contiguous-region: property indicating that the region
is the default region for all contiguous memory
allocations, Linux specific (optional)
+linux,memory-limit: property specifying an upper bound on the physical address
+ of the region if the region is placed dynamically. If no limit
+ is specificed, the region may be placed anywhere in the physical
+ address space. 0 may be used to specify lowmem (i.e. the region
+ will be placed in the direct mapped lowmem region)
label: an internal name used for automatically associating the
cma region with a given device. The label is optional;
if the label is not given the client is responsible for
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 606383a..adac211 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -212,6 +212,7 @@
unsigned long len;
__be32 *prop;
char *name;
+ phys_addr_t limit = MEMBLOCK_ALLOC_ANYWHERE;
if (!of_get_flat_dt_prop(node, "linux,contiguous-region", NULL))
return 0;
@@ -225,9 +226,13 @@
name = of_get_flat_dt_prop(node, "label", NULL);
- pr_info("Found %s, memory base %lx, size %ld MiB\n", uname,
- (unsigned long)base, (unsigned long)size / SZ_1M);
- dma_contiguous_reserve_area(size, &base, MEMBLOCK_ALLOC_ANYWHERE, name);
+ prop = of_get_flat_dt_prop(node, "linux,memory-limit", NULL);
+ if (prop)
+ limit = be32_to_cpu(prop[0]);
+
+ pr_info("Found %s, memory base %lx, size %ld MiB, limit %pa\n", uname,
+ (unsigned long)base, (unsigned long)size / SZ_1M, &limit);
+ dma_contiguous_reserve_area(size, &base, limit, name);
return 0;
}