Renesas R-Car Gen4 PCIe controllers have an unexpected register value on the dbi+0x97b register. So, add a new capability flag "EDMA_UNROLL" which would force the unrolled eDMA mapping for the problematic device, as suggested by Serge Semin. Suggested-by: Serge Semin <fancer.lancer@xxxxxxxxx> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> --- 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 8b2978c6eb23..e405bfae0191 100644 --- a/drivers/pci/controller/dwc/pcie-designware.c +++ b/drivers/pci/controller/dwc/pcie-designware.c @@ -881,8 +881,14 @@ 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 + * may 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 06e044e2163a..2639206b4c18 100644 --- a/drivers/pci/controller/dwc/pcie-designware.h +++ b/drivers/pci/controller/dwc/pcie-designware.h @@ -54,8 +54,9 @@ /* 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 #define dw_pcie_cap_is(_pci, _cap) \ test_bit(DW_PCIE_CAP_ ## _cap, &(_pci)->caps) -- 2.25.1
