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Subject[PATCH v2] mtd: onenand: omap2: Disable DMA for HIGHMEM buffers
dma_map_single doesn't get the proper DMA address for vmalloced area,
so disable DMA in this case.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Reported-by: "H. Nikolaus Schaller" <hns@goldelico.com>
Tested-by: "H. Nikolaus Schaller" <hns@goldelico.com>
---
Changes:
-v2: Added Tested-by tag, based on v4.17-rc1 (no change in patch itself)

drivers/mtd/nand/onenand/omap2.c | 105 +++++++++++--------------------
1 file changed, 38 insertions(+), 67 deletions(-)

diff --git a/drivers/mtd/nand/onenand/omap2.c b/drivers/mtd/nand/onenand/omap2.c
index 9c159f0dd9a6..321137158ff3 100644
--- a/drivers/mtd/nand/onenand/omap2.c
+++ b/drivers/mtd/nand/onenand/omap2.c
@@ -375,56 +375,42 @@ static int omap2_onenand_read_bufferram(struct mtd_info *mtd, int area,
{
struct omap2_onenand *c = container_of(mtd, struct omap2_onenand, mtd);
struct onenand_chip *this = mtd->priv;
- dma_addr_t dma_src, dma_dst;
- int bram_offset;
+ struct device *dev = &c->pdev->dev;
void *buf = (void *)buffer;
+ dma_addr_t dma_src, dma_dst;
+ int bram_offset, err;
size_t xtra;
- int ret;

bram_offset = omap2_onenand_bufferram_offset(mtd, area) + area + offset;
- if (bram_offset & 3 || (size_t)buf & 3 || count < 384)
- goto out_copy;
-
- /* panic_write() may be in an interrupt context */
- if (in_interrupt() || oops_in_progress)
+ /*
+ * If the buffer address is not DMA-able, len is not long enough to make
+ * DMA transfers profitable or panic_write() may be in an interrupt
+ * context fallback to PIO mode.
+ */
+ if (!virt_addr_valid(buf) || bram_offset & 3 || (size_t)buf & 3 ||
+ count < 384 || in_interrupt() || oops_in_progress )
goto out_copy;

- if (buf >= high_memory) {
- struct page *p1;
-
- if (((size_t)buf & PAGE_MASK) !=
- ((size_t)(buf + count - 1) & PAGE_MASK))
- goto out_copy;
- p1 = vmalloc_to_page(buf);
- if (!p1)
- goto out_copy;
- buf = page_address(p1) + ((size_t)buf & ~PAGE_MASK);
- }
-
xtra = count & 3;
if (xtra) {
count -= xtra;
memcpy(buf + count, this->base + bram_offset + count, xtra);
}

+ dma_dst = dma_map_single(dev, buf, count, DMA_FROM_DEVICE);
dma_src = c->phys_base + bram_offset;
- dma_dst = dma_map_single(&c->pdev->dev, buf, count, DMA_FROM_DEVICE);
- if (dma_mapping_error(&c->pdev->dev, dma_dst)) {
- dev_err(&c->pdev->dev,
- "Couldn't DMA map a %d byte buffer\n",
- count);
- goto out_copy;
- }

- ret = omap2_onenand_dma_transfer(c, dma_src, dma_dst, count);
- dma_unmap_single(&c->pdev->dev, dma_dst, count, DMA_FROM_DEVICE);
-
- if (ret) {
- dev_err(&c->pdev->dev, "timeout waiting for DMA\n");
+ if (dma_mapping_error(dev, dma_dst)) {
+ dev_err(dev, "Couldn't DMA map a %d byte buffer\n", count);
goto out_copy;
}

- return 0;
+ err = omap2_onenand_dma_transfer(c, dma_src, dma_dst, count);
+ dma_unmap_single(dev, dma_dst, count, DMA_FROM_DEVICE);
+ if (!err)
+ return 0;
+
+ dev_err(dev, "timeout waiting for DMA\n");

out_copy:
memcpy(buf, this->base + bram_offset, count);
@@ -437,49 +423,34 @@ static int omap2_onenand_write_bufferram(struct mtd_info *mtd, int area,
{
struct omap2_onenand *c = container_of(mtd, struct omap2_onenand, mtd);
struct onenand_chip *this = mtd->priv;
- dma_addr_t dma_src, dma_dst;
- int bram_offset;
+ struct device *dev = &c->pdev->dev;
void *buf = (void *)buffer;
- int ret;
+ dma_addr_t dma_src, dma_dst;
+ int bram_offset, err;

bram_offset = omap2_onenand_bufferram_offset(mtd, area) + area + offset;
- if (bram_offset & 3 || (size_t)buf & 3 || count < 384)
- goto out_copy;
-
- /* panic_write() may be in an interrupt context */
- if (in_interrupt() || oops_in_progress)
+ /*
+ * If the buffer address is not DMA-able, len is not long enough to make
+ * DMA transfers profitable or panic_write() may be in an interrupt
+ * context fallback to PIO mode.
+ */
+ if (!virt_addr_valid(buf) || bram_offset & 3 || (size_t)buf & 3 ||
+ count < 384 || in_interrupt() || oops_in_progress )
goto out_copy;

- if (buf >= high_memory) {
- struct page *p1;
-
- if (((size_t)buf & PAGE_MASK) !=
- ((size_t)(buf + count - 1) & PAGE_MASK))
- goto out_copy;
- p1 = vmalloc_to_page(buf);
- if (!p1)
- goto out_copy;
- buf = page_address(p1) + ((size_t)buf & ~PAGE_MASK);
- }
-
- dma_src = dma_map_single(&c->pdev->dev, buf, count, DMA_TO_DEVICE);
+ dma_src = dma_map_single(dev, buf, count, DMA_TO_DEVICE);
dma_dst = c->phys_base + bram_offset;
- if (dma_mapping_error(&c->pdev->dev, dma_src)) {
- dev_err(&c->pdev->dev,
- "Couldn't DMA map a %d byte buffer\n",
- count);
- return -1;
- }
-
- ret = omap2_onenand_dma_transfer(c, dma_src, dma_dst, count);
- dma_unmap_single(&c->pdev->dev, dma_src, count, DMA_TO_DEVICE);
-
- if (ret) {
- dev_err(&c->pdev->dev, "timeout waiting for DMA\n");
+ if (dma_mapping_error(dev, dma_src)) {
+ dev_err(dev, "Couldn't DMA map a %d byte buffer\n", count);
goto out_copy;
}

- return 0;
+ err = omap2_onenand_dma_transfer(c, dma_src, dma_dst, count);
+ dma_unmap_page(dev, dma_src, count, DMA_TO_DEVICE);
+ if (!err)
+ return 0;
+
+ dev_err(dev, "timeout waiting for DMA\n");

out_copy:
memcpy(this->base + bram_offset, buf, count);
--
2.17.0
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