From 17209dfb35a228e597a387bfc83b68093b247f78 Mon Sep 17 00:00:00 2001 From: Stanimir Varbanov Date: Fri, 18 Dec 2015 14:38:55 +0200 Subject: [PATCH] PCI: designware: Ensure ATU is enabled before IO/conf space accesses Read back the ATU CR2 register to ensure ATU programming is effective before any subsequent I/O or config space accesses. Without this, PCI device enumeration is unreliable. [bhelgaas: changelog, comment] Signed-off-by: Stanimir Varbanov Signed-off-by: Bjorn Helgaas Acked-by: Pratyush Anand --- drivers/pci/host/pcie-designware.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c index 540f077c37ea..7353371b3f15 100644 --- a/drivers/pci/host/pcie-designware.c +++ b/drivers/pci/host/pcie-designware.c @@ -154,6 +154,8 @@ static int dw_pcie_wr_own_conf(struct pcie_port *pp, int where, int size, static void dw_pcie_prog_outbound_atu(struct pcie_port *pp, int index, int type, u64 cpu_addr, u64 pci_addr, u32 size) { + u32 val; + dw_pcie_writel_rc(pp, PCIE_ATU_REGION_OUTBOUND | index, PCIE_ATU_VIEWPORT); dw_pcie_writel_rc(pp, lower_32_bits(cpu_addr), PCIE_ATU_LOWER_BASE); @@ -164,6 +166,12 @@ static void dw_pcie_prog_outbound_atu(struct pcie_port *pp, int index, dw_pcie_writel_rc(pp, upper_32_bits(pci_addr), PCIE_ATU_UPPER_TARGET); dw_pcie_writel_rc(pp, type, PCIE_ATU_CR1); dw_pcie_writel_rc(pp, PCIE_ATU_ENABLE, PCIE_ATU_CR2); + + /* + * Make sure ATU enable takes effect before any subsequent config + * and I/O accesses. + */ + dw_pcie_readl_rc(pp, PCIE_ATU_CR2, &val); } static struct irq_chip dw_msi_irq_chip = { -- 2.20.1