Hi Richard, Richard Zhu writes: >> -----Original Message----- >> From: Baruch Siach [mailto:baruch@xxxxxxxxxx] >> Sent: 2018年12月13日 16:13 >> To: Richard Zhu <hongxing.zhu@xxxxxxx> >> Cc: bhelgaas@xxxxxxxxxx; lorenzo.pieralisi@xxxxxxx; >> l.stach@xxxxxxxxxxxxxx; andrew.smirnov@xxxxxxxxx; >> linux-pci@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; >> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx >> Subject: Re: [v2] PCI: imx: make msi work without pcieportbus >> >> Richard Zhu writes: >> > 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. >> > >> > 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)) { >> >> CONFIG_PCI_IMX6 depends on CONFIG_PCI_MSI_IRQ_DOMAIN that in turn >> depends on CONFIG_PCI_MSI. So this condition should always be true. If so, >> you can drop this one as well. > [Richard Zhu] Thanks. > Can we have the double check here? > Thus, it's aligned to the MSI enable codes in the other place of the driver. > For example: > ... > if (IS_ENABLED(CONFIG_PCI_MSI)) > dw_pcie_msi_init(pp); > ... > Secondly, the driver has a better portability with the double check here. > How do you think about it? Kernel driver are not meant to be "portable" as far as I understand. But I'll let the PCI maintainers comment on that. For reference, mainline kernel makes CONFIG_PCI_MSI a hard dependency of pci-imx6 since commit 3ee803641e76 ("PCI/MSI: irqchip: Fix PCI_MSI dependencies") in v4.8. In my opinion, if the driver actually compiles and is usable without CONFIG_PCI_MSI then Kconfig dependencies should reflect that. >> > + 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; >> > } baruch -- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch@xxxxxxxxxx - tel: +972.52.368.4656, http://www.tkos.co.il -
