Hi Bjorn: Thanks for your kindly review. > -----Original Message----- > From: Bjorn Helgaas [mailto:helgaas@xxxxxxxxxx] > Sent: 2018年12月13日 22:41 > To: Richard Zhu <hongxing.zhu@xxxxxxx> > Cc: 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 > > On Thu, Dec 13, 2018 at 08:02:11AM +0000, Richard Zhu wrote: > > 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. > > This subject line and changelog need some rework. I can't understand > what's going on at all. Lorenzo or I can help craft something, but I don't > understand enough to propose anything yet. > > "MSI_EN" doesn't appear in the driver; I assume it's some device-specific > signal. [Richard Zhu] MSI_EN is the MSI Enable bit(BIT(0)) of the Message Control Register for MSI. I would change it to MSI Enable bit later. > > "iMX" does not look like the typical spelling. You could use "imx6" > to refer to the driver, but in this case you're talking about the hardware itself, > not the driver. So you should use "i.MX6" or whatever the appropriate brand > is. [Richard Zhu] Okay, i.MX6 would be used. > > If "PCIEPORTBUS driver is selected" means "CONFIG_PCIEPORTBUS=y", say > that. The connection of portdrv (which is generic PCIe support) to MSI_EN > (which is apparently device-specific) is unclear. It would be helpful if you > could connect those dots a little more. [Richard Zhu] That's right, thanks. > > "MSI works fine on iMX PCIe before." Before what? Is this a regression, > where MSI worked before some commit and this patch fixes it? [Richard Zhu] MSI works fine on iMX6 PCIe before commit "f3fdfc4ac3". It's a limitation of the iMX6 PCIe, otherwise a regression. MSI should not have dependency on the selection of the PCIEPORTBUS > > Please rewrap the changelog so it uses the entire 80-column width. > Wrap to 75 so it still fits when "git log" adds the 4 char indent. > [Richard Zhu] Okay. > > 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 > > I wish this didn't look quite so much like a PCI core name, because this is > really an i.MX-specific offset. It looks like the PCIE_RC_* names are all > similar i.MX-specific things. Shouldn't this match those? > [Richard Zhu] How about to replace it by PCIE_RC_IMX6_MSI_CAP? Best Regards Richard Zhu > > #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; > > } > > -- > > 2.7.4 > > > > > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > > https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flist > > > s.infradead.org%2Fmailman%2Flistinfo%2Flinux-arm-kernel&data=02%7 > C > > > 01%7Chongxing.zhu%40nxp.com%7C58a92c7a1c3e4a1fa43908d661090b4f% > 7C686ea > > > 1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C636803088809543819& > sdata=qy6 > > q1tawIz%2FU757D5PN5vE3OqNOf70fMHLFBVZPI9AI%3D&reserved=0
