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Subject[PATCH v6 08/11] drivers: dma-contiguous: add initialization from device tree
Date
Refactor internal dma_contiguous_init_reserved_mem() function, which
creates CMA area from previously reserved memory region and add support
for handling 'shared-dma-pool' reserved-memory device tree nodes.

Based on previous code provided by Josh Cartwright <joshc@codeaurora.org>

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
drivers/base/dma-contiguous.c | 129 ++++++++++++++++++++++++++++++++++-------
1 file changed, 107 insertions(+), 22 deletions(-)

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 165c2c299e57..0efdf1986990 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -182,6 +182,49 @@ static int __init cma_init_reserved_areas(void)
core_initcall(cma_init_reserved_areas);

/**
+ * dma_contiguous_init_reserved_mem() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @res_cma: Pointer to store the created cma region.
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas for specific
+ * devices.
+ */
+static int __init dma_contiguous_init_reserved_mem(phys_addr_t size,
+ phys_addr_t base, struct cma **res_cma)
+{
+ struct cma *cma = &cma_areas[cma_area_count];
+ 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;
+
+ /* Sanitise input arguments */
+ alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+ if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size)
+ return -EINVAL;
+
+ cma->base_pfn = PFN_DOWN(base);
+ cma->count = size >> PAGE_SHIFT;
+ *res_cma = cma;
+ cma_area_count++;
+
+ /* Architecture specific contiguous memory fixup. */
+ dma_contiguous_early_fixup(base, size);
+ return 0;
+}
+
+/**
* dma_contiguous_reserve_area() - reserve custom contiguous area
* @size: Size of the reserved area (in bytes),
* @base: Base address of the reserved area optional, use 0 for any
@@ -197,7 +240,6 @@ core_initcall(cma_init_reserved_areas);
int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
phys_addr_t limit, struct cma **res_cma)
{
- struct cma *cma = &cma_areas[cma_area_count];
phys_addr_t alignment;
int ret = 0;

@@ -205,12 +247,6 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
(unsigned long)size, (unsigned long)base,
(unsigned long)limit);

- /* Sanity checks */
- if (cma_area_count == ARRAY_SIZE(cma_areas)) {
- pr_err("Not enough slots for CMA reserved regions!\n");
- return -ENOSPC;
- }
-
if (!size)
return -EINVAL;

@@ -241,21 +277,12 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
}
}

- /*
- * Each reserved area must be initialised later, when more kernel
- * subsystems (like slab allocator) are available.
- */
- cma->base_pfn = PFN_DOWN(base);
- cma->count = size >> PAGE_SHIFT;
- *res_cma = cma;
- cma_area_count++;
-
- pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
- (unsigned long)base);
-
- /* Architecture specific contiguous memory fixup. */
- dma_contiguous_early_fixup(base, size);
- return 0;
+ ret = dma_contiguous_init_reserved_mem(size, base, res_cma);
+ if (ret == 0) {
+ pr_info("CMA: reserved %ld MiB at %08lx\n",
+ (unsigned long)size / SZ_1M, (unsigned long)base);
+ return 0;
+ }
err:
pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
return ret;
@@ -357,3 +384,61 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,

return true;
}
+
+/*
+ * 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 const struct reserved_mem_ops rmem_cma_ops = {
+ .device_init = rmem_cma_device_init,
+};
+
+static int __init rmem_cma_setup(struct reserved_mem *rmem,
+ unsigned long node,
+ const char *uname)
+{
+ phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+ phys_addr_t mask = align - 1;
+ struct cma *cma;
+ int err;
+
+ if (!of_get_flat_dt_prop(node, "reusable", NULL))
+ return -EINVAL;
+
+ if ((rmem->base & mask) || (rmem->size & mask)) {
+ pr_err("Reserved memory: incorrect alignment of CMA region\n");
+ return -EINVAL;
+ }
+
+ err = dma_contiguous_init_reserved_mem(rmem->size, rmem->base, &cma);
+ if (err) {
+ pr_err("Reserved memory: unable to setup CMA region\n");
+ return err;
+ }
+
+ 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
--
1.7.9.5


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