Hi Lucas: > -----Original Message----- > From: Lucas Stach [mailto:l.stach@xxxxxxxxxxxxxx] > Sent: 2018年12月13日 17:19 > To: Richard Zhu <hongxing.zhu@xxxxxxx>; bhelgaas@xxxxxxxxxx; > lorenzo.pieralisi@xxxxxxx; andrew.smirnov@xxxxxxxxx > Cc: linux-pci@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx > Subject: Re: [v2] PCI: imx: make msi work without pcieportbus > > Hi Richard, > > Am Donnerstag, den 13.12.2018, 08:02 +0000 schrieb Richard Zhu: > > MSI_EN of iMX PCIe RC would be asserted when PCIEPORTBUS driver is > > selected. > > Thus, the MSI works fine on iMX PCIe before. > > Assert it unconditionally when MSI is supported. > > Otherwise, the MSI wouldn't be triggered although the EP is present > > and the MSIs are assigned. > > Thanks for digging into this issue. This seems like the right way forward. > However, did you test this with devices using legacy IRQs? > I.e. booting with "nomsi" on the kernel command line to see if legacy IRQs still > work if this bit is set, or if we need to avoid setting this when the user > explicitly requests to disable MSIs? > > Regards, > Lucas > [Richard Zhu] Thanks for your review. The Legacy INTx is broken. The MSI_EN bit shouldn't be asserted when the user explicitly requests to disable MSIs. BTW, regarding to Baruch's comments, it seems that all the (IS_ENABLED(CONFIG_PCI_MSI) check in the dwc host drivers are not required anymore, since the depends on PCI_MSI_IRQ_DOMAIN, right? > > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx> > > --- > > drivers/pci/controller/dwc/pci-imx6.c | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c > > b/drivers/pci/controller/dwc/pci-imx6.c > > index 26087b3..d3e4296 100644 > > --- a/drivers/pci/controller/dwc/pci-imx6.c > > +++ b/drivers/pci/controller/dwc/pci-imx6.c > > @@ -74,6 +74,7 @@ struct imx6_pcie { > > > #define PHY_PLL_LOCK_WAIT_USLEEP_MAX 200 > > > > /* PCIe Root Complex registers (memory-mapped) */ > > > +#define PCI_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 > > @@ -926,6 +927,7 @@ 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) > > @@ -1070,6 +1072,11 @@ static int imx6_pcie_probe(struct > > platform_device *pdev) > > > ret = imx6_add_pcie_port(imx6_pcie, pdev); > > > if (ret < 0) > > > return ret; > > > + if (IS_ENABLED(CONFIG_PCI_MSI)) { > > > + val = dw_pcie_readw_dbi(pci, PCI_MSI_CAP + > PCI_MSI_FLAGS); > > > + val |= PCI_MSI_FLAGS_ENABLE; > > > + dw_pcie_writew_dbi(pci, PCI_MSI_CAP + PCI_MSI_FLAGS, val); > > > + } > > > > > return 0; > > }
