From: Richard Zhu hongxing.zhu@nxp.com
[ Upstream commit 75cb8d20c112aba70f23d98e3f8d0a38ace16006 ]
The MSI Enable bit in the MSI Capability (PCIe r4.0, sec 7.7.1.2) controls whether a Function can request service using MSI.
i.MX6 Root Ports implement the MSI Capability and may use MSI to request service for events like PME, hotplug, AER, etc. In addition, on i.MX6, the MSI Enable bit controls delivery of MSI interrupts from components below the Root Port.
Prior to f3fdfc4ac3a2 ("PCI: Remove host driver Kconfig selection of CONFIG_PCIEPORTBUS"), enabling CONFIG_PCI_IMX6 automatically also enabled CONFIG_PCIEPORTBUS, and when portdrv claimed the Root Ports, it set the MSI Enable bit so it could use PME, hotplug, AER, etc. As a side effect, that also enabled delivery of MSI interrupts from downstream components.
The imx6q-pcie driver itself does not depend on portdrv, so set MSI Enable in imx6q-pcie so MSI from downstream components works even if nobody uses MSI for the Root Port events.
Fixes: f3fdfc4ac3a2 ("PCI: Remove host driver Kconfig selection of CONFIG_PCIEPORTBUS") Signed-off-by: Richard Zhu hongxing.zhu@nxp.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Tested-by: Sven Van Asbroeck TheSven73@googlemail.com Tested-by: Trent Piepho tpiepho@impinj.com Reviewed-by: Lucas Stach l.stach@pengutronix.de Acked-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/controller/dwc/pci-imx6.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c index 975050a69494..3826b444298c 100644 --- a/drivers/pci/controller/dwc/pci-imx6.c +++ b/drivers/pci/controller/dwc/pci-imx6.c @@ -66,6 +66,7 @@ struct imx6_pcie { #define PHY_PLL_LOCK_WAIT_USLEEP_MAX 200
/* PCIe Root Complex registers (memory-mapped) */ +#define PCIE_RC_IMX6_MSI_CAP 0x50 #define PCIE_RC_LCR 0x7c #define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1 0x1 #define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2 0x2 @@ -682,6 +683,7 @@ static int imx6_pcie_probe(struct platform_device *pdev) struct resource *dbi_base; struct device_node *node = dev->of_node; int ret; + u16 val;
imx6_pcie = devm_kzalloc(dev, sizeof(*imx6_pcie), GFP_KERNEL); if (!imx6_pcie) @@ -816,6 +818,14 @@ static int imx6_pcie_probe(struct platform_device *pdev) if (ret < 0) return ret;
+ if (pci_msi_enabled()) { + val = dw_pcie_readw_dbi(pci, PCIE_RC_IMX6_MSI_CAP + + PCI_MSI_FLAGS); + val |= PCI_MSI_FLAGS_ENABLE; + dw_pcie_writew_dbi(pci, PCIE_RC_IMX6_MSI_CAP + PCI_MSI_FLAGS, + val); + } + return 0; }