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Date: Wed, 2 May 2018 13:46:39 +0300
From: Peter Ujfalusi <peter.ujfalusi@...com>
To: Ladislav Michl <ladis@...ux-mips.org>,
Boris Brezillon <boris.brezillon@...tlin.com>
CC: <linux-kernel@...r.kernel.org>, <linux-mtd@...ts.infradead.org>,
Roger Quadros <rogerq@...com>,
Aaro Koskinen <aaro.koskinen@....fi>,
Tony Lindgren <tony@...mide.com>,
"H. Nikolaus Schaller" <hns@...delico.com>,
Andreas Kemnade <andreas@...nade.info>
Subject: Re: [PATCH v3] mtd: onenand: omap2: Disable DMA for HIGHMEM buffers
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.ujfalusi@...com>
> Signed-off-by: Ladislav Michl <ladis@...ux-mips.org>
> Reported-by: "H. Nikolaus Schaller" <hns@...delico.com>
> Tested-by: "H. Nikolaus Schaller" <hns@...delico.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
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
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