Hello,
On 2/14/2013 10:34 PM, Laura Abbott wrote:
On 2/14/2013 4:45 AM, Marek Szyprowski wrote:
<snip>
+name: an name given to the defined region.
+base-address: the base address of the defined region.
+size: the size of the memory region.
+linux,contiguous-region: property indicating that the defined memory
+ region is used for contiguous memory allocations,
+ Linux specific (optional)
+linux,default-contiguous-region: property indicating that the region
+ is the default region for all contiguous memory
+ allocations, Linux specific (optional)
+
+
I don't see any code actually implementing the
default-contiguous-region binding. Currently on ARM systems we will
still setup the default region based on the Kconfig. Is this intentional?
Nope, this was my fault. I've missed the fixup which added support for
default-contiguous-region (it was just a few lines more to cma_fdt_scan()
function).
diff --git a/drivers/base/dma-contiguous.c
b/drivers/base/dma-contiguous.c
index 085389c..5761f73 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -24,6 +24,9 @@
#include <linux/memblock.h>
#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_platform.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/page-isolation.h>
@@ -177,6 +180,35 @@ no_mem:
return ERR_PTR(ret);
}
+/*****************************************************************************/
+
+#ifdef CONFIG_OF
+int __init cma_fdt_scan(unsigned long node, const char *uname,
+ int depth, void *data)
+{
+ phys_addr_t base, size;
+ unsigned long len;
+ __be32 *prop;
+
+ if (strncmp(uname, "region@", 7) != 0 || depth != 2 ||
+ !of_get_flat_dt_prop(node, "contiguous-region", NULL))
The documentation says "linux,contiguous-region"
Right, lack of another fixup. It looks that I posted an incomplete
version, I'm sorry.
I hurried that time (it was my last day in the office before going for
holidays).
+#ifdef CONFIG_OF
+static void cma_assign_device_from_dt(struct device *dev)
+{
+ struct device_node *node;
+ struct cma *cma;
+ u32 value;
+
+ node = of_parse_phandle(dev->of_node, "linux,contiguous-region",
0);
+ if (!node)
+ return;
+ if (of_property_read_u32(node, "reg", &value) && !value)
+ return;
+ cma = cma_get_area(value);
+ if (!cma)
+ return;
+
+ dev_set_cma_area(dev, cma);
+ pr_info("Assigned CMA region at %lx to %s device\n", (unsigned
long)value, dev_name(dev));
+}
+
This scheme of associating devices with CMA regions by base does not
work if you want to let CMA figure out where to place the region (base
= 0). Can we use the name to associate the device with the region? I
had been working on something similar internally and that was the only
solution I had come up with to associate arbitrary CMA nodes with devices.
Right, support for base = 0 requires different handling, but I thought
that if
we use the device tree approach, the designer already knows the complete
memory
configuration, so providing the correct base address is not that hard.
Best regards
--
Marek Szyprowski
Samsung Poland R&D Center
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