dma-buf: heaps: Add CMA heap to dmabuf heaps

This adds a CMA heap, which allows userspace to allocate
a dma-buf of contiguous memory out of a CMA region.

This code is an evolution of the Android ION implementation, so
thanks to its original author and maintainters:
  Benjamin Gaignard, Laura Abbott, and others!

NOTE: This patch only adds the default CMA heap. We will enable
selectively adding other CMA memory regions to the dmabuf heaps
interface with a later patch (which requires a dt binding)

Cc: Laura Abbott <labbott@redhat.com>
Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Liam Mark <lmark@codeaurora.org>
Cc: Pratik Patel <pratikp@codeaurora.org>
Cc: Brian Starkey <Brian.Starkey@arm.com>
Cc: Vincent Donnefort <Vincent.Donnefort@arm.com>
Cc: Sudipto Paul <Sudipto.Paul@arm.com>
Cc: Andrew F. Davis <afd@ti.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chenbo Feng <fengc@google.com>
Cc: Alistair Strachan <astrachan@google.com>
Cc: Hridya Valsaraju <hridya@google.com>
Cc: Sandeep Patil <sspatil@google.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Reviewed-by: Brian Starkey <brian.starkey@arm.com>
Acked-by: Sandeep Patil <sspatil@android.com>
Acked-by: Laura Abbott <labbott@redhat.com>
Tested-by: Ayan Kumar Halder <ayan.halder@arm.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191203172641.66642-5-john.stultz@linaro.org

diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
index 205052744169ed468a5eeee94ee76039432ebb3c..a5eef06c422644e8aadaf5aff2bd9a33c49c1ba3 100644 (file)
--- a/drivers/dma-buf/heaps/Kconfig
+++ b/drivers/dma-buf/heaps/Kconfig
@@ -4,3 +4,11 @@ config DMABUF_HEAPS_SYSTEM
        help
          Choose this option to enable the system dmabuf heap. The system heap
          is backed by pages from the buddy allocator. If in doubt, say Y.
+
+config DMABUF_HEAPS_CMA
+       bool "DMA-BUF CMA Heap"
+       depends on DMABUF_HEAPS && DMA_CMA
+       help
+         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.

diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile
index d1808eca258109c7529ac4b9ec225aad5b70bfff..6e54cdec3da02bbc4b5d7e10ebb881855ab2ac0e 100644 (file)
--- a/drivers/dma-buf/heaps/Makefile
+++ b/drivers/dma-buf/heaps/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-y                                  += heap-helpers.o
 obj-$(CONFIG_DMABUF_HEAPS_SYSTEM)      += system_heap.o
+obj-$(CONFIG_DMABUF_HEAPS_CMA)         += cma_heap.o

diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c
new file mode 100644 (file)
index 0000000..626cf7f
--- /dev/null
+++ b/drivers/dma-buf/heaps/cma_heap.c
@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DMABUF CMA heap exporter
+ *
+ * Copyright (C) 2012, 2019 Linaro Ltd.
+ * Author: <benjamin.gaignard@linaro.org> for ST-Ericsson.
+ */
+
+#include <linux/cma.h>
+#include <linux/device.h>
+#include <linux/dma-buf.h>
+#include <linux/dma-heap.h>
+#include <linux/dma-contiguous.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/highmem.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/scatterlist.h>
+#include <linux/sched/signal.h>
+
+#include "heap-helpers.h"
+
+struct cma_heap {
+       struct dma_heap *heap;
+       struct cma *cma;
+};
+
+static void cma_heap_free(struct heap_helper_buffer *buffer)
+{
+       struct cma_heap *cma_heap = dma_heap_get_drvdata(buffer->heap);
+       unsigned long nr_pages = buffer->pagecount;
+       struct page *cma_pages = buffer->priv_virt;
+
+       /* free page list */
+       kfree(buffer->pages);
+       /* release memory */
+       cma_release(cma_heap->cma, cma_pages, nr_pages);
+       kfree(buffer);
+}
+
+/* dmabuf heap CMA operations functions */
+static int cma_heap_allocate(struct dma_heap *heap,
+                            unsigned long len,
+                            unsigned long fd_flags,
+                            unsigned long heap_flags)
+{
+       struct cma_heap *cma_heap = dma_heap_get_drvdata(heap);
+       struct heap_helper_buffer *helper_buffer;
+       struct page *cma_pages;
+       size_t size = PAGE_ALIGN(len);
+       unsigned long nr_pages = size >> PAGE_SHIFT;
+       unsigned long align = get_order(size);
+       struct dma_buf *dmabuf;
+       int ret = -ENOMEM;
+       pgoff_t pg;
+
+       if (align > CONFIG_CMA_ALIGNMENT)
+               align = CONFIG_CMA_ALIGNMENT;
+
+       helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL);
+       if (!helper_buffer)
+               return -ENOMEM;
+
+       init_heap_helper_buffer(helper_buffer, cma_heap_free);
+       helper_buffer->heap = heap;
+       helper_buffer->size = len;
+
+       cma_pages = cma_alloc(cma_heap->cma, nr_pages, align, false);
+       if (!cma_pages)
+               goto free_buf;
+
+       if (PageHighMem(cma_pages)) {
+               unsigned long nr_clear_pages = nr_pages;
+               struct page *page = cma_pages;
+
+               while (nr_clear_pages > 0) {
+                       void *vaddr = kmap_atomic(page);
+
+                       memset(vaddr, 0, PAGE_SIZE);
+                       kunmap_atomic(vaddr);
+                       /*
+                        * Avoid wasting time zeroing memory if the process
+                        * has been killed by by SIGKILL
+                        */
+                       if (fatal_signal_pending(current))
+                               goto free_cma;
+
+                       page++;
+                       nr_clear_pages--;
+               }
+       } else {
+               memset(page_address(cma_pages), 0, size);
+       }
+
+       helper_buffer->pagecount = nr_pages;
+       helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
+                                            sizeof(*helper_buffer->pages),
+                                            GFP_KERNEL);
+       if (!helper_buffer->pages) {
+               ret = -ENOMEM;
+               goto free_cma;
+       }
+
+       for (pg = 0; pg < helper_buffer->pagecount; pg++)
+               helper_buffer->pages[pg] = &cma_pages[pg];
+
+       /* create the dmabuf */
+       dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
+       if (IS_ERR(dmabuf)) {
+               ret = PTR_ERR(dmabuf);
+               goto free_pages;
+       }
+
+       helper_buffer->dmabuf = dmabuf;
+       helper_buffer->priv_virt = cma_pages;
+
+       ret = dma_buf_fd(dmabuf, fd_flags);
+       if (ret < 0) {
+               dma_buf_put(dmabuf);
+               /* just return, as put will call release and that will free */
+               return ret;
+       }
+
+       return ret;
+
+free_pages:
+       kfree(helper_buffer->pages);
+free_cma:
+       cma_release(cma_heap->cma, cma_pages, nr_pages);
+free_buf:
+       kfree(helper_buffer);
+       return ret;
+}
+
+static const struct dma_heap_ops cma_heap_ops = {
+       .allocate = cma_heap_allocate,
+};
+
+static int __add_cma_heap(struct cma *cma, void *data)
+{
+       struct cma_heap *cma_heap;
+       struct dma_heap_export_info exp_info;
+
+       cma_heap = kzalloc(sizeof(*cma_heap), GFP_KERNEL);
+       if (!cma_heap)
+               return -ENOMEM;
+       cma_heap->cma = cma;
+
+       exp_info.name = cma_get_name(cma);
+       exp_info.ops = &cma_heap_ops;
+       exp_info.priv = cma_heap;
+
+       cma_heap->heap = dma_heap_add(&exp_info);
+       if (IS_ERR(cma_heap->heap)) {
+               int ret = PTR_ERR(cma_heap->heap);
+
+               kfree(cma_heap);
+               return ret;
+       }
+
+       return 0;
+}
+
+static int add_default_cma_heap(void)
+{
+       struct cma *default_cma = dev_get_cma_area(NULL);
+       int ret = 0;
+
+       if (default_cma)
+               ret = __add_cma_heap(default_cma, NULL);
+
+       return ret;
+}
+module_init(add_default_cma_heap);
+MODULE_DESCRIPTION("DMA-BUF CMA Heap");
+MODULE_LICENSE("GPL v2");