| Message ID | 20240523100315.7226-1-hongchi.peng@siengine.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 1134289b6b93d73721340b66c310fd985385e8fa |
| Headers | show |
| Series | usb: dwc2: gadget: Don't write invalid mapped sg entries into dma_desc with iommu enabled | expand |
On 5/23/24 14:03, Peng Hongchi wrote: > When using dma_map_sg() to map the scatterlist with iommu enabled, > the entries in the scatterlist can be mergerd into less but longer > entries in the function __finalise_sg(). So that the number of > valid mapped entries is actually smaller than ureq->num_reqs,and > there are still some invalid entries in the scatterlist with > dma_addr=0xffffffff and len=0. Writing these invalid sg entries > into the dma_desc can cause a data transmission error. > > The function dma_map_sg() returns the number of valid map entries > and the return value is assigned to usb_request::num_mapped_sgs in > function usb_gadget_map_request_by_dev(). So that just write valid > mapped entries into dma_desc according to the usb_request::num_mapped_sgs, > and set the IOC bit if it's the last valid mapped entry. > > This patch poses no risk to no-iommu situation, cause > ureq->num_mapped_sgs equals ureq->num_sgs while using dma_direct_map_sg() > to map the scatterlist whith iommu disabled. > > Signed-off-by: Peng Hongchi <hongchi.peng@siengine.com> Acked-by: Minas Harutyunyan <hminas@synopsys.com> > --- > drivers/usb/dwc2/gadget.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c > index 74ac79abd8f3..e7bf9cc635be 100644 > --- a/drivers/usb/dwc2/gadget.c > +++ b/drivers/usb/dwc2/gadget.c > @@ -885,10 +885,10 @@ static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep, > } > > /* DMA sg buffer */ > - for_each_sg(ureq->sg, sg, ureq->num_sgs, i) { > + for_each_sg(ureq->sg, sg, ureq->num_mapped_sgs, i) { > dwc2_gadget_fill_nonisoc_xfer_ddma_one(hs_ep, &desc, > sg_dma_address(sg) + sg->offset, sg_dma_len(sg), > - sg_is_last(sg)); > + (i == (ureq->num_mapped_sgs - 1))); > desc_count += hs_ep->desc_count; > } >
diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c index 74ac79abd8f3..e7bf9cc635be 100644 --- a/drivers/usb/dwc2/gadget.c +++ b/drivers/usb/dwc2/gadget.c @@ -885,10 +885,10 @@ static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep, } /* DMA sg buffer */ - for_each_sg(ureq->sg, sg, ureq->num_sgs, i) { + for_each_sg(ureq->sg, sg, ureq->num_mapped_sgs, i) { dwc2_gadget_fill_nonisoc_xfer_ddma_one(hs_ep, &desc, sg_dma_address(sg) + sg->offset, sg_dma_len(sg), - sg_is_last(sg)); + (i == (ureq->num_mapped_sgs - 1))); desc_count += hs_ep->desc_count; }
When using dma_map_sg() to map the scatterlist with iommu enabled, the entries in the scatterlist can be mergerd into less but longer entries in the function __finalise_sg(). So that the number of valid mapped entries is actually smaller than ureq->num_reqs,and there are still some invalid entries in the scatterlist with dma_addr=0xffffffff and len=0. Writing these invalid sg entries into the dma_desc can cause a data transmission error. The function dma_map_sg() returns the number of valid map entries and the return value is assigned to usb_request::num_mapped_sgs in function usb_gadget_map_request_by_dev(). So that just write valid mapped entries into dma_desc according to the usb_request::num_mapped_sgs, and set the IOC bit if it's the last valid mapped entry. This patch poses no risk to no-iommu situation, cause ureq->num_mapped_sgs equals ureq->num_sgs while using dma_direct_map_sg() to map the scatterlist whith iommu disabled. Signed-off-by: Peng Hongchi <hongchi.peng@siengine.com> --- drivers/usb/dwc2/gadget.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)