drivers: dma-contiguous: add initialization from device tree
Add device tree support for contiguous memory regions defined in device
tree. Initialization is done in 2 steps. First, the contiguous memory is
reserved, what happens very early, when only flattened device tree is
available. Then on device initialization the corresponding cma regions are
assigned to device structures.
Change-Id: Ic242499b64875ee57a346d7cbc8a34ebd64e68d2
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 1937db8..cd341e8 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>
@@ -181,6 +184,35 @@
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))
+ return 0;
+
+ prop = of_get_flat_dt_prop(node, "reg", &len);
+ if (!prop || (len != 2 * sizeof(unsigned long)))
+ return 0;
+
+ base = be32_to_cpu(prop[0]);
+ size = be32_to_cpu(prop[1]);
+
+ 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, 0);
+
+ return 0;
+}
+#endif
+
/**
* dma_contiguous_reserve() - reserve area for contiguous memory handling
* @limit: End address of the reserved memory (optional, 0 for any).
@@ -219,6 +251,9 @@
if (dma_contiguous_reserve_area(sel_size, &base, limit) == 0)
dma_contiguous_def_base = base;
}
+#ifdef CONFIG_OF
+ of_scan_flat_dt(cma_fdt_scan, NULL);
+#endif
};
/**
@@ -323,6 +358,40 @@
return 0;
}
+#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));
+}
+
+static int cma_device_init_notifier_call(struct notifier_block *nb,
+ unsigned long event, void *data)
+{
+ struct device *dev = data;
+ if (event == BUS_NOTIFY_ADD_DEVICE && dev->of_node)
+ cma_assign_device_from_dt(dev);
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block cma_dev_init_nb = {
+ .notifier_call = cma_device_init_notifier_call,
+};
+#endif
+
static int __init cma_init_reserved_areas(void)
{
struct cma *cma;
@@ -344,6 +413,9 @@
dev_set_cma_area(cma_maps[i].dev, cma);
}
+#ifdef CONFIG_OF
+ bus_register_notifier(&platform_bus_type, &cma_dev_init_nb);
+#endif
return 0;
}
core_initcall(cma_init_reserved_areas);