| Message ID | d38a9c1a87c4e40ad6d17fcbe0fd41b33d7d2912.1448270813.git.stanimir.varbanov@linaro.org |
|---|---|
| State | New |
| Headers | show |
diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c index 02a7452bdf23..e15a2ae1583f 100644 --- a/drivers/pci/host/pcie-designware.c +++ b/drivers/pci/host/pcie-designware.c @@ -164,6 +164,11 @@ 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); + /* + * ensure that the ATU enable has been happaned before accessing + * pci configuration/io spaces through dw_pcie_cfg_[read|write]. + */ + smp_wmb(); } static struct irq_chip dw_msi_irq_chip = {
Add 'write memory' barrier after enable region in PCIE_ATU_CR2 register. The barrier is needed to ensure that the region enable request has been reached it's destination at time when we read/write to PCI configuration space. Without this barrier PCI device enumeration during kernel boot is not reliable, and reading configuration space for particular PCI device on the bus returns zero aka no device. Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org> --- drivers/pci/host/pcie-designware.c | 5 +++++ 1 file changed, 5 insertions(+) -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/