Add a function to create CMA region from previously reserved memory
and add support for handling 'shared-dma-pool' reserved-memory device
tree nodes.
Based on previous code provided by Josh Cartwright <joshc@xxxxxxxxxxxxxx>
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
drivers/base/dma-contiguous.c | 67 +++++++++++++++++++++++++++++++++++++++++++
include/linux/cma.h | 3 ++
mm/cma.c | 62 ++++++++++++++++++++++++++++++++-------
3 files changed, 121 insertions(+), 11 deletions(-)
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 6606abdf880c..b77ea8bac176 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -211,3 +211,70 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
{
return cma_release(dev_get_cma_area(dev), pages, count);
}
+
+/*
+ * Support for reserved memory regions defined in device tree
+ */
+#ifdef CONFIG_OF_RESERVED_MEM
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_reserved_mem.h>
+
+#undef pr_fmt
+#define pr_fmt(fmt) fmt
+
+static void rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev)
+{
+ struct cma *cma = rmem->priv;
+ dev_set_cma_area(dev, cma);
+}
+
+static void rmem_cma_device_release(struct reserved_mem *rmem,
+ struct device *dev)
+{
+ dev_set_cma_area(dev, NULL);
+}
+
+static const struct reserved_mem_ops rmem_cma_ops = {
+ .device_init = rmem_cma_device_init,
+ .device_release = rmem_cma_device_release,
+};
+
+static int __init rmem_cma_setup(struct reserved_mem *rmem)
+{
+ phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+ phys_addr_t mask = align - 1;
+ unsigned long node = rmem->fdt_node;
+ struct cma *cma;
+ int err;
+
+ if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
+ of_get_flat_dt_prop(node, "no-map", NULL))
+ return -EINVAL;
+
+ if ((rmem->base & mask) || (rmem->size & mask)) {
+ pr_err("Reserved memory: incorrect alignment of CMA region\n");
+ return -EINVAL;
+ }
+
+ err = cma_init_reserved_mem(rmem->base, rmem->size, 0, &cma);
+ if (err) {
+ pr_err("Reserved memory: unable to setup CMA region\n");
+ return err;
+ }
+ /* Architecture specific contiguous memory fixup. */
+ dma_contiguous_early_fixup(rmem->base, rmem->size);
+
+ if (of_get_flat_dt_prop(node, "linux,cma-default", NULL))
+ dma_contiguous_set_default(cma);
+
+ rmem->ops = &rmem_cma_ops;
+ rmem->priv = cma;
+
+ pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
+ &rmem->base, (unsigned long)rmem->size / SZ_1M);
+
+ return 0;
+}
+RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);
+#endif
diff --git a/include/linux/cma.h b/include/linux/cma.h
index 32cab7a425f9..9a18a2b1934c 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -16,6 +16,9 @@ extern int __init cma_declare_contiguous(phys_addr_t size,
phys_addr_t base, phys_addr_t limit,
phys_addr_t alignment, unsigned int order_per_bit,
bool fixed, struct cma **res_cma);
+extern int cma_init_reserved_mem(phys_addr_t size,
+ phys_addr_t base, int order_per_bit,
+ struct cma **res_cma);
extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
extern bool cma_release(struct cma *cma, struct page *pages, int count);
#endif
diff --git a/mm/cma.c b/mm/cma.c
index 4b251b037e1b..b3d8b925ad34 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -140,6 +140,54 @@ static int __init cma_init_reserved_areas(void)
core_initcall(cma_init_reserved_areas);
/**
+ * cma_init_reserved_mem() - create custom contiguous area from reserved memory
+ * @base: Base address of the reserved area
+ * @size: Size of the reserved area (in bytes),
+ * @order_per_bit: Order of pages represented by one bit on bitmap.
+ * @res_cma: Pointer to store the created cma region.
+ *
+ * This function creates custom contiguous area from already reserved memory.
+ */
+int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
+ int order_per_bit, struct cma **res_cma)
+{
+ struct cma *cma;
+ phys_addr_t alignment;
+
+ /* Sanity checks */
+ if (cma_area_count == ARRAY_SIZE(cma_areas)) {
+ pr_err("Not enough slots for CMA reserved regions!\n");
+ return -ENOSPC;
+ }
+
+ if (!size || !memblock_is_region_reserved(base, size))
+ return -EINVAL;
+
+ /* ensure minimal alignment requied by mm core */
+ alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+
+ /* alignment should be aligned with order_per_bit */
+ if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit))
+ return -EINVAL;
+
+ if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size)
+ return -EINVAL;
+
+ /*
+ * Each reserved area must be initialised later, when more kernel
+ * subsystems (like slab allocator) are available.
+ */
+ cma = &cma_areas[cma_area_count];
+ cma->base_pfn = PFN_DOWN(base);
+ cma->count = size >> PAGE_SHIFT;
+ cma->order_per_bit = order_per_bit;
+ *res_cma = cma;
+ cma_area_count++;
+
+ return 0;
+}
+
+/**
* cma_declare_contiguous() - reserve custom contiguous area
* @base: Base address of the reserved area optional, use 0 for any
* @size: Size of the reserved area (in bytes),
@@ -162,7 +210,6 @@ int __init cma_declare_contiguous(phys_addr_t base,
phys_addr_t alignment, unsigned int order_per_bit,
bool fixed, struct cma **res_cma)
{
- struct cma *cma;
int ret = 0;
pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
@@ -214,16 +261,9 @@ int __init cma_declare_contiguous(phys_addr_t base,
}
}
- /*
- * Each reserved area must be initialised later, when more kernel
- * subsystems (like slab allocator) are available.
- */
- cma = &cma_areas[cma_area_count];
- cma->base_pfn = PFN_DOWN(base);
- cma->count = size >> PAGE_SHIFT;
- cma->order_per_bit = order_per_bit;
- *res_cma = cma;
- cma_area_count++;
+ ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma);
+ if (ret)
+ goto err;
pr_info("Reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
(unsigned long)base);
--
1.9.2
--
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