[RFC][PATCH 2/4] mm: cma: Add dma_heap flag to cma structure

John Stultz john.stultz at linaro.org
Fri May 1 07:39:47 UTC 2020

This patch adds a dma_heap flag on the cma structure,
along with accessors to set and read the flag.

This is then used to process and store the "linux,cma-heap"
property documented in the previous patch.

Cc: Rob Herring <robh+dt at kernel.org>
Cc: Sumit Semwal <sumit.semwal at linaro.org>
Cc: "Andrew F. Davis" <afd at ti.com>
Cc: Benjamin Gaignard <benjamin.gaignard at linaro.org>
Cc: Liam Mark <lmark at codeaurora.org>
Cc: Pratik Patel <pratikp at codeaurora.org>
Cc: Laura Abbott <labbott at redhat.com>
Cc: Brian Starkey <Brian.Starkey at arm.com>
Cc: Chenbo Feng <fengc at google.com>
Cc: Alistair Strachan <astrachan at google.com>
Cc: Sandeep Patil <sspatil at google.com>
Cc: Hridya Valsaraju <hridya at google.com>
Cc: Christoph Hellwig <hch at lst.de>
Cc: Marek Szyprowski <m.szyprowski at samsung.com>
Cc: Robin Murphy <robin.murphy at arm.com>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: devicetree at vger.kernel.org
Cc: dri-devel at lists.freedesktop.org
Cc: linux-mm at kvack.org
Signed-off-by: John Stultz <john.stultz at linaro.org>
 include/linux/cma.h     |  3 +++
 kernel/dma/contiguous.c |  3 +++
 mm/cma.c                | 11 +++++++++++
 mm/cma.h                |  1 +
 4 files changed, 18 insertions(+)

diff --git a/include/linux/cma.h b/include/linux/cma.h
index 6ff79fefd01f..d8b8e6ce221c 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -25,6 +25,9 @@ extern phys_addr_t cma_get_base(const struct cma *cma);
 extern unsigned long cma_get_size(const struct cma *cma);
 extern const char *cma_get_name(const struct cma *cma);
+extern void __init cma_enable_dma_heap(struct cma *cma, bool enabled);
+extern bool cma_dma_heap_enabled(struct cma *cma);
 extern int __init cma_declare_contiguous_nid(phys_addr_t base,
 			phys_addr_t size, phys_addr_t limit,
 			phys_addr_t alignment, unsigned int order_per_bit,
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index 8bc6f2d670f9..f667fd51daa2 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -303,6 +303,7 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
 	phys_addr_t mask = align - 1;
 	unsigned long node = rmem->fdt_node;
 	bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
+	bool heap_exported = of_get_flat_dt_prop(node, "linux,cma-heap", NULL);
 	struct cma *cma;
 	int err;
@@ -332,6 +333,8 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
 	if (default_cma)
+	cma_enable_dma_heap(cma, heap_exported);
 	rmem->ops = &rmem_cma_ops;
 	rmem->priv = cma;
diff --git a/mm/cma.c b/mm/cma.c
index 0463ad2ce06b..ec671bd8f66e 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -55,6 +55,16 @@ const char *cma_get_name(const struct cma *cma)
 	return cma->name ? cma->name : "(undefined)";
+void __init cma_enable_dma_heap(struct cma *cma, bool enabled)
+	cma->dma_heap = enabled;
+bool cma_dma_heap_enabled(struct cma *cma)
+	return !!cma->dma_heap;
 static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
 					     unsigned int align_order)
@@ -157,6 +167,7 @@ static int __init cma_init_reserved_areas(void)
  * cma_init_reserved_mem() - create custom contiguous area from reserved memory
  * @base: Base address of the reserved area
diff --git a/mm/cma.h b/mm/cma.h
index 33c0b517733c..6fe2242c724f 100644
--- a/mm/cma.h
+++ b/mm/cma.h
@@ -13,6 +13,7 @@ struct cma {
 	spinlock_t mem_head_lock;
 	const char *name;
+	bool dma_heap;
 extern struct cma cma_areas[MAX_CMA_AREAS];

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