| Message ID | 20220610091459.17612-23-Sergey.Semin@baikalelectronics.ru (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | dmaengine: dw-edma: Add RP/EP local DMA controllers support | expand |
On Fri, Jun 10, 2022 at 12:14:57PM +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> Thanks, Mani > > --- > > Changelog v2: > - Fix the comment a bit to being clearer. (@Manivannan) > > Changelog v3: > - Conditionally set dchan->dev->device.dma_coherent field since it can > be missing on some platforms. (@Manivannan) > - Remove Manivannan' rb and tb tags since the patch content has been > changed. > --- > drivers/dma/dw-edma/dw-edma-core.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c > index 6a8282eaebaf..4f56149dc8d8 100644 > --- a/drivers/dma/dw-edma/dw-edma-core.c > +++ b/drivers/dma/dw-edma/dw-edma-core.c > @@ -716,6 +716,26 @@ 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; > + > +#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ > + defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \ > + defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) > + dchan->dev->device.dma_coherent = chan->dw->chip->dev->dma_coherent; > +#endif > + > + 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 >
diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c index 6a8282eaebaf..4f56149dc8d8 100644 --- a/drivers/dma/dw-edma/dw-edma-core.c +++ b/drivers/dma/dw-edma/dw-edma-core.c @@ -716,6 +716,26 @@ 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; + +#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ + defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \ + defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) + dchan->dev->device.dma_coherent = chan->dw->chip->dev->dma_coherent; +#endif + + 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;
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> --- Changelog v2: - Fix the comment a bit to being clearer. (@Manivannan) Changelog v3: - Conditionally set dchan->dev->device.dma_coherent field since it can be missing on some platforms. (@Manivannan) - Remove Manivannan' rb and tb tags since the patch content has been changed. --- drivers/dma/dw-edma/dw-edma-core.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)