On 2018-05-02 13:41, Ladislav Michl wrote:
> dma_map_single does not work for vmalloc-ed buffers,
> so disable DMA in this case.

Reviewed-by: Peter Ujfalusi <peter.ujfal...@ti.com>

> Signed-off-by: Ladislav Michl <la...@linux-mips.org>
> Reported-by: "H. Nikolaus Schaller" <h...@goldelico.com>
> Tested-by: "H. Nikolaus Schaller" <h...@goldelico.com>
> ---
>  Changes:
>   -v2: Added Tested-by tag, based on v4.17-rc1 (no change in patch itself)
>   -v3: Reworded commit log
> 
>  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);
> 

- Péter

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