On Fri, Aug 25, 2023 at 06:32:09PM +0900, Yoshihiro Shimoda wrote: > Renesas R-Car Gen4 PCIe controllers have an unexpected register value in > the eDMA CTRL register. So, add a new capability flag "EDMA_UNROLL" > which would force the unrolled eDMA mapping for the problematic device. > > Suggested-by: Serge Semin <fancer.lancer@xxxxxxxxx> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> > Reviewed-by: Serge Semin <fancer.lancer@xxxxxxxxx> > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > --- > drivers/pci/controller/dwc/pcie-designware.c | 8 +++++++- > drivers/pci/controller/dwc/pcie-designware.h | 5 +++-- > 2 files changed, 10 insertions(+), 3 deletions(-) > > diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c > index c4998194fe74..4812ce040f1e 100644 > --- a/drivers/pci/controller/dwc/pcie-designware.c > +++ b/drivers/pci/controller/dwc/pcie-designware.c > @@ -883,8 +883,14 @@ static int dw_pcie_edma_find_chip(struct dw_pcie *pci) > * Indirect eDMA CSRs access has been completely removed since v5.40a > * thus no space is now reserved for the eDMA channels viewport and > * former DMA CTRL register is no longer fixed to FFs. > + * > + * Note that Renesas R-Car S4-8's PCIe controllers for unknown reason > + * have zeros in the eDMA CTRL register even though the HW-manual > + * explicitly states there must FFs if the unrolled mapping is enabled. > + * For such cases the low-level drivers are supposed to manually > + * activate the unrolled mapping to bypass the auto-detection procedure. > */ > - if (dw_pcie_ver_is_ge(pci, 540A)) > + if (dw_pcie_ver_is_ge(pci, 540A) || dw_pcie_cap_is(pci, EDMA_UNROLL)) > val = 0xFFFFFFFF; > else > val = dw_pcie_readl_dbi(pci, PCIE_DMA_VIEWPORT_BASE + PCIE_DMA_CTRL); > diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h > index b731e38a71fc..c7759a508ca9 100644 > --- a/drivers/pci/controller/dwc/pcie-designware.h > +++ b/drivers/pci/controller/dwc/pcie-designware.h > @@ -51,8 +51,9 @@ > > /* DWC PCIe controller capabilities */ > #define DW_PCIE_CAP_REQ_RES 0 > -#define DW_PCIE_CAP_IATU_UNROLL 1 > -#define DW_PCIE_CAP_CDM_CHECK 2 > +#define DW_PCIE_CAP_EDMA_UNROLL 1 > +#define DW_PCIE_CAP_IATU_UNROLL 2 > +#define DW_PCIE_CAP_CDM_CHECK 3 Why did you make the new DW_PCIE_CAP_EDMA_UNROLL "1" and shift all the existing ones down? If they don't need to be ordered like this, leaving the existing ones alone and making DW_PCIE_CAP_EDMA_UNROLL "3" would be a simpler one-line diff. > #define dw_pcie_cap_is(_pci, _cap) \ > test_bit(DW_PCIE_CAP_ ## _cap, &(_pci)->caps) > -- > 2.25.1 >
