mtd: onenand: omap2: Disable DMA for HIGHMEM buffers

dma_map_single does not work for vmalloc-ed buffers,
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>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>

1 files 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);