| Message ID | 20220503225104.12108-24-Sergey.Semin@baikalelectronics.ru |
|---|---|
| State | New |
| Headers | show |
| Series | dmaengine: dw-edma: Add RP/EP local DMA controllers support | expand |
On Wed, May 04, 2022 at 01:51:01AM +0300, Serge Semin wrote: > DW eDMA doesn't perform any translation of the traffic generated on the > CPU/Application side. It just generates read/write AXI-bus requests with > the specified addresses. But in case if the dma-ranges DT-property is > specified for a platform device node, Linux will use it to map the CPU > memory regions into the DMAable bus ranges. This isn't what we want for > the eDMA embedded into the locally accessed DW PCIe Root Port and > End-point. In order to work that around let's set the chan_dma_dev flag > for each DW eDMA channel thus forcing the client drivers to getting a > custom dma-ranges-less parental device for the mappings. > > Note it will only work for the client drivers using the > dmaengine_get_dma_device() method to get the parental DMA device. > > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> > > --- > > Changelog v2: > - Fix the comment a bit to being clearer. (@Manivannan) > --- > drivers/dma/dw-edma/dw-edma-core.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c > index 6a8282eaebaf..908607785401 100644 > --- a/drivers/dma/dw-edma/dw-edma-core.c > +++ b/drivers/dma/dw-edma/dw-edma-core.c > @@ -716,6 +716,21 @@ static int dw_edma_alloc_chan_resources(struct dma_chan *dchan) > if (chan->status != EDMA_ST_IDLE) > return -EBUSY; > > + /* Bypass the dma-ranges based memory regions mapping for the eDMA > + * controlled from the CPU/Application side since in that case > + * the local memory address is left untranslated. > + */ > + if (chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) { > + dchan->dev->chan_dma_dev = true; > + > + dchan->dev->device.dma_coherent = chan->dw->chip->dev->dma_coherent; I happen to test this series on Qcom ARM32 machine and it errors out during the compilation due to "dma_coherent" not available on !SWIOTLB ARM32 configs. Thanks, Mani > + dma_coerce_mask_and_coherent(&dchan->dev->device, > + dma_get_mask(chan->dw->chip->dev)); > + dchan->dev->device.dma_parms = chan->dw->chip->dev->dma_parms; > + } else { > + dchan->dev->chan_dma_dev = false; > + } > + > pm_runtime_get(chan->dw->chip->dev); > > return 0; > -- > 2.35.1 >
On Tue, May 24, 2022 at 06:49:59PM +0530, Manivannan Sadhasivam wrote: > On Wed, May 04, 2022 at 01:51:01AM +0300, Serge Semin wrote: > > DW eDMA doesn't perform any translation of the traffic generated on the > > CPU/Application side. It just generates read/write AXI-bus requests with > > the specified addresses. But in case if the dma-ranges DT-property is > > specified for a platform device node, Linux will use it to map the CPU > > memory regions into the DMAable bus ranges. This isn't what we want for > > the eDMA embedded into the locally accessed DW PCIe Root Port and > > End-point. In order to work that around let's set the chan_dma_dev flag > > for each DW eDMA channel thus forcing the client drivers to getting a > > custom dma-ranges-less parental device for the mappings. > > > > Note it will only work for the client drivers using the > > dmaengine_get_dma_device() method to get the parental DMA device. > > > > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> > > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> > > > > --- > > > > Changelog v2: > > - Fix the comment a bit to being clearer. (@Manivannan) > > --- > > drivers/dma/dw-edma/dw-edma-core.c | 15 +++++++++++++++ > > 1 file changed, 15 insertions(+) > > > > diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c > > index 6a8282eaebaf..908607785401 100644 > > --- a/drivers/dma/dw-edma/dw-edma-core.c > > +++ b/drivers/dma/dw-edma/dw-edma-core.c > > @@ -716,6 +716,21 @@ static int dw_edma_alloc_chan_resources(struct dma_chan *dchan) > > if (chan->status != EDMA_ST_IDLE) > > return -EBUSY; > > > > + /* Bypass the dma-ranges based memory regions mapping for the eDMA > > + * controlled from the CPU/Application side since in that case > > + * the local memory address is left untranslated. > > + */ > > + if (chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) { > > + dchan->dev->chan_dma_dev = true; > > + > > + dchan->dev->device.dma_coherent = chan->dw->chip->dev->dma_coherent; > > I happen to test this series on Qcom ARM32 machine and it errors out during the > compilation due to "dma_coherent" not available on !SWIOTLB ARM32 configs. Nice catch! Thanks. I'll fix it in the next patchset version. -Sergey > > Thanks, > Mani > > > + dma_coerce_mask_and_coherent(&dchan->dev->device, > > + dma_get_mask(chan->dw->chip->dev)); > > + dchan->dev->device.dma_parms = chan->dw->chip->dev->dma_parms; > > + } else { > > + dchan->dev->chan_dma_dev = false; > > + } > > + > > pm_runtime_get(chan->dw->chip->dev); > > > > return 0; > > -- > > 2.35.1 > > > > -- > மணிவண்ணன் சதாசிவம்
diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c index 6a8282eaebaf..908607785401 100644 --- a/drivers/dma/dw-edma/dw-edma-core.c +++ b/drivers/dma/dw-edma/dw-edma-core.c @@ -716,6 +716,21 @@ static int dw_edma_alloc_chan_resources(struct dma_chan *dchan) if (chan->status != EDMA_ST_IDLE) return -EBUSY; + /* Bypass the dma-ranges based memory regions mapping for the eDMA + * controlled from the CPU/Application side since in that case + * the local memory address is left untranslated. + */ + if (chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) { + dchan->dev->chan_dma_dev = true; + + dchan->dev->device.dma_coherent = chan->dw->chip->dev->dma_coherent; + dma_coerce_mask_and_coherent(&dchan->dev->device, + dma_get_mask(chan->dw->chip->dev)); + dchan->dev->device.dma_parms = chan->dw->chip->dev->dma_parms; + } else { + dchan->dev->chan_dma_dev = false; + } + pm_runtime_get(chan->dw->chip->dev); return 0;