Hi Péter, On Mon, Apr 16, 2018 at 02:34:54PM +0300, Peter Ujfalusi wrote: > On 2018-04-16 09:52, Ladislav Michl wrote: > > dma_map_single doesn't get the proper DMA address for vmalloced area, > > Which is not a big surprise as vmalloc will allocate contiguous virtual > memory (which might corresponds to non-contiguous physical memory). Even > if you somehow get the physical address of the start of the vmalloced > buffer, you don't really know how long that chunk is and where the > buffer continues in physical memory. > > Creating sg_list of the vmalloced buffer should be possible also by > walking the virt memory and get the pages with vmalloc_to_page(). > I don't think there is a generic vmalloc_to_sg(), one can be implemented.
Please see previous bugreport here: https://marc.info/?l=linux-omap&m=152337752611812&w=2 Unfortunately issue was noticed after v4.16 come out and v4.17-rc1 was about to released. Thus safe change was introduced. Best regards, ladis > > so disable DMA in this case. > > > > 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) > > > > 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
