[PATCH v18 11/20] PCI: dwc: Add EDMA_UNROLL capability flag
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From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Date: 2023-07-21 07:45:10
Also in:
linux-pci, linux-renesas-soc
Subsystem:
pci driver for synopsys designware, pci native host bridge and endpoint drivers, pci subsystem, the rest · Maintainers:
Jingoo Han, Manivannan Sadhasivam, Lorenzo Pieralisi, Krzysztof Wilczyński, Bjorn Helgaas, Linus Torvalds
Revision v18 of 11 in this series; 1 review trailer.
Revisions (11)
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. Suggested-by: Serge Semin <redacted> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Reviewed-by: Serge Semin <redacted> --- 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 94bc20f5f600..6821446d7c66 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 #define dw_pcie_cap_is(_pci, _cap) \ test_bit(DW_PCIE_CAP_ ## _cap, &(_pci)->caps)
--
2.25.1