@@ -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);
@@ -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)
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@gmail.com> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> --- drivers/pci/controller/dwc/pcie-designware.c | 8 +++++++- drivers/pci/controller/dwc/pcie-designware.h | 5 +++-- 2 files changed, 10 insertions(+), 3 deletions(-)