The CMA heap's name in devtmpfs can vary depending on how the heap is
defined. Its name defaults to "reserved", but if a CMA area is defined
in the devicetree, the heap takes on the devicetree node's name, such as
"default-pool" or "linux,cma". To simplify naming, unconditionally name
it "default_cma_region", but keep a legacy node in place backed by the
same underlying allocator for backwards compatibility.
Reviewed-by: Maxime Ripard <mrip...@kernel.org>
Signed-off-by: Jared Kangas <jkan...@redhat.com>
---
Documentation/userspace-api/dma-buf-heaps.rst | 7 +++++--
drivers/dma-buf/heaps/Kconfig | 10 ++++++++++
drivers/dma-buf/heaps/cma_heap.c | 20 ++++++++++++++++++-
3 files changed, 34 insertions(+), 3 deletions(-)
diff --git a/Documentation/userspace-api/dma-buf-heaps.rst
b/Documentation/userspace-api/dma-buf-heaps.rst
index 23bd0bd7b0654..1dfe5e7acd5a3 100644
--- a/Documentation/userspace-api/dma-buf-heaps.rst
+++ b/Documentation/userspace-api/dma-buf-heaps.rst
@@ -21,5 +21,8 @@ following heaps:
usually created either through the kernel commandline through the
``cma`` parameter, a memory region Device-Tree node with the
``linux,cma-default`` property set, or through the ``CMA_SIZE_MBYTES`` or
- ``CMA_SIZE_PERCENTAGE`` Kconfig options. Depending on the platform, it
- might be called ``reserved``, ``linux,cma``, or ``default-pool``.
+ ``CMA_SIZE_PERCENTAGE`` Kconfig options. The heap's name in devtmpfs is
+ ``default_cma_region``. For backwards compatibility, when the
+ ``DMABUF_HEAPS_CMA_LEGACY`` Kconfig option is set, a duplicate node is
+ created following legacy naming conventions; the legacy name might be
+ ``reserved``, ``linux,cma``, or ``default-pool``.
diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
index a5eef06c42264..bb369b38b001a 100644
--- a/drivers/dma-buf/heaps/Kconfig
+++ b/drivers/dma-buf/heaps/Kconfig
@@ -12,3 +12,13 @@ config DMABUF_HEAPS_CMA
Choose this option to enable dma-buf CMA heap. This heap is backed
by the Contiguous Memory Allocator (CMA). If your system has these
regions, you should say Y here.
+
+config DMABUF_HEAPS_CMA_LEGACY
+ bool "Legacy DMA-BUF CMA Heap"
+ default y
+ depends on DMABUF_HEAPS_CMA
+ help
+ Add a duplicate CMA-backed dma-buf heap with legacy naming derived
+ from the CMA area's devicetree node, or "reserved" if the area is not
+ defined in the devicetree. This uses the same underlying allocator as
+ CONFIG_DMABUF_HEAPS_CMA.
diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c
index e998d8ccd1dc6..0df0071119754 100644
--- a/drivers/dma-buf/heaps/cma_heap.c
+++ b/drivers/dma-buf/heaps/cma_heap.c
@@ -9,6 +9,9 @@
* Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
* Andrew F. Davis <a...@ti.com>
*/
+
+#define pr_fmt(fmt) "cma_heap: " fmt
+
#include <linux/cma.h>
#include <linux/dma-buf.h>
#include <linux/dma-heap.h>
@@ -22,6 +25,7 @@
#include <linux/slab.h>
#include <linux/vmalloc.h>
+#define DEFAULT_CMA_NAME "default_cma_region"
struct cma_heap {
struct dma_heap *heap;
@@ -394,15 +398,29 @@ static int __init __add_cma_heap(struct cma *cma, const
char *name)
static int __init add_default_cma_heap(void)
{
struct cma *default_cma = dev_get_cma_area(NULL);
+ const char *legacy_cma_name;
int ret;
if (!default_cma)
return 0;
- ret = __add_cma_heap(default_cma, cma_get_name(default_cma));
+ ret = __add_cma_heap(default_cma, DEFAULT_CMA_NAME);
if (ret)
return ret;
+ if (IS_ENABLED(CONFIG_DMABUF_HEAPS_CMA_LEGACY)) {
+ legacy_cma_name = cma_get_name(default_cma);
+ if (!strcmp(legacy_cma_name, DEFAULT_CMA_NAME)) {
+ pr_warn("legacy name and default name are the same,
skipping legacy heap\n");
+ return 0;
+ }
+
+ ret = __add_cma_heap(default_cma, legacy_cma_name);
+ if (ret)
+ pr_warn("failed to add legacy heap: %pe\n",
+ ERR_PTR(ret));
+ }
+
return 0;
}
module_init(add_default_cma_heap);
--
2.49.0
