Hi Lucas:
> -----Original Message-----
> From: Lucas Stach [mailto:l.st...@pengutronix.de]
> Sent: 2018年12月13日 17:19
> To: Richard Zhu <hongxing....@nxp.com>; bhelg...@google.com;
> lorenzo.pieral...@arm.com; andrew.smir...@gmail.com
> Cc: linux-...@vger.kernel.org; linux-arm-ker...@lists.infradead.org;
> linux-kernel@vger.kernel.org
> 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....@nxp.com>
> > ---
> > 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;
> > }
