The "DesignWare Cores PCI Express Controller Register Descriptions, Version 4.60a", section "1.21.70 IATU_LWR_TARGET_ADDR_OFF_INBOUND_i", fields LWR_TARGET_RW and LWR_TARGET_HW both state that: "Field size depends on log2(BAR_MASK+1) in BAR match mode."
I.e. only the upper bits are writable, and the number of writable bits is dependent on the configured BAR_MASK.
If we do not write the BAR_MASK before writing the iATU registers, we are relying the reset value of the BAR_MASK being larger than the requested BAR size (which is supplied in the struct pci_epf_bar which is passed to pci_epc_set_bar()). The reset value of the BAR_MASK is SoC dependent.
Thus, if the struct pci_epf_bar requests a BAR size that is larger than the reset value of the BAR_MASK, the iATU will try to write to read-only bits, which will cause the iATU to end up redirecting to a physical address that is different from the address that was intended.
Thus, we should always write the iATU registers after writing the BAR_MASK.
Cc: stable@vger.kernel.org Fixes: f8aed6ec624f ("PCI: dwc: designware: Add EP mode support") Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Signed-off-by: Niklas Cassel cassel@kernel.org --- .../pci/controller/dwc/pcie-designware-ep.c | 28 ++++++++++--------- 1 file changed, 15 insertions(+), 13 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c index f3ac7d46a855..bad588ef69a4 100644 --- a/drivers/pci/controller/dwc/pcie-designware-ep.c +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c @@ -222,19 +222,10 @@ static int dw_pcie_ep_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no, if ((flags & PCI_BASE_ADDRESS_MEM_TYPE_64) && (bar & 1)) return -EINVAL;
- reg = PCI_BASE_ADDRESS_0 + (4 * bar); - - if (!(flags & PCI_BASE_ADDRESS_SPACE)) - type = PCIE_ATU_TYPE_MEM; - else - type = PCIE_ATU_TYPE_IO; - - ret = dw_pcie_ep_inbound_atu(ep, func_no, type, epf_bar->phys_addr, bar); - if (ret) - return ret; - if (ep->epf_bar[bar]) - return 0; + goto config_atu; + + reg = PCI_BASE_ADDRESS_0 + (4 * bar);
dw_pcie_dbi_ro_wr_en(pci);
@@ -246,9 +237,20 @@ static int dw_pcie_ep_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no, dw_pcie_ep_writel_dbi(ep, func_no, reg + 4, 0); }
- ep->epf_bar[bar] = epf_bar; dw_pcie_dbi_ro_wr_dis(pci);
+config_atu: + if (!(flags & PCI_BASE_ADDRESS_SPACE)) + type = PCIE_ATU_TYPE_MEM; + else + type = PCIE_ATU_TYPE_IO; + + ret = dw_pcie_ep_inbound_atu(ep, func_no, type, epf_bar->phys_addr, bar); + if (ret) + return ret; + + ep->epf_bar[bar] = epf_bar; + return 0; }