Hi Robin On Thu, Dec 15, 2022 at 02:53:03AM +0300, Serge Semin wrote: > DW PCIe Root Ports and End-points can be equipped with the DW eDMA engine. > In that case it is critical to have the platform device pre-initialized > with a valid DMA-mask so the drivers using the eDMA-engine would be able > to allocate the DMA-able buffers. The MSI-capable data requires to be > allocated from the lowest 4GB region. Since that procedure implies the > DMA-mask change we need to restore the mask set by the low-level drivers > after the MSI-data allocation is done. I dropped the patch [PATCH v6 22/24] dmaengine: dw-edma: Bypass dma-ranges mapping for the local setup Link: https://lore.kernel.org/linux-pci/20221107210438.1515-23-Sergey.Semin@xxxxxxxxxxxxxxxxxxxx/ from the series. It has turned to be useless since your commit f1ad5338a4d5 ("of: Fix "dma-ranges" handling for bus controllers"). Instead I added the patches [PATCH v7 23/25] PCI: dwc: Restore DMA-mask after MSI-data allocation and [PATCH v7 24/25] PCI: bt1: Set 64-bit DMA-mask to this patchset in order to properly handle the DMA-mask. Could you please give your opinion on these patches? -Serge(y) > > Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> > > --- > > Changelog v7: > - This is a new patch added on v7 stage of the series. (@Robin) > --- > drivers/pci/controller/dwc/pcie-designware-host.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c > index 5762bd306261..1a3dae1f6aa2 100644 > --- a/drivers/pci/controller/dwc/pcie-designware-host.c > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c > @@ -326,7 +326,7 @@ static int dw_pcie_msi_host_init(struct dw_pcie_rp *pp) > struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > struct device *dev = pci->dev; > struct platform_device *pdev = to_platform_device(dev); > - u64 *msi_vaddr; > + u64 *msi_vaddr, dma_mask; > int ret; > u32 ctrl, num_ctrls; > > @@ -366,6 +366,13 @@ static int dw_pcie_msi_host_init(struct dw_pcie_rp *pp) > dw_chained_msi_isr, pp); > } > > + /* > + * Save and then restore the DMA-mask pre-set by the low-level drivers > + * after allocating the MSI-capable region. The mask might be useful for > + * the controllers with the embedded eDMA engine. > + */ > + dma_mask = dma_get_mask(dev); > + > ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32)); > if (ret) > dev_warn(dev, "Failed to set DMA mask to 32-bit. Devices with only 32-bit MSI support may not work properly\n"); > @@ -378,6 +385,10 @@ static int dw_pcie_msi_host_init(struct dw_pcie_rp *pp) > return -ENOMEM; > } > > + ret = dma_set_mask_and_coherent(dev, dma_mask); > + if (ret) > + dev_warn(dev, "Failed to re-store DMA-mask\n"); > + > return 0; > } > > -- > 2.38.1 > >
