linux-kernel - RE: [v5] PCI: imx: make msi work without CONFIG

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Date:   Fri, 21 Dec 2018 00:42:26 +0000
From:   Richard Zhu <hongxing.zhu@....com>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>
CC:     "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
        "l.stach@...gutronix.de" <l.stach@...gutronix.de>,
        "andrew.smirnov@...il.com" <andrew.smirnov@...il.com>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [v5] PCI: imx: make msi work without CONFIG_PCIEPORTBUS=y

Hi Lorenzo:

> -----Original Message-----
> From: Lorenzo Pieralisi [mailto:lorenzo.pieralisi@....com]
> Sent: 2018年12月20日 22:50
> To: Richard Zhu <hongxing.zhu@....com>
> Cc: bhelgaas@...gle.com; l.stach@...gutronix.de;
> andrew.smirnov@...il.com; linux-pci@...r.kernel.org;
> linux-arm-kernel@...ts.infradead.org; linux-kernel@...r.kernel.org
> Subject: Re: [v5] PCI: imx: make msi work without CONFIG_PCIEPORTBUS=y
> 
> On Wed, Dec 19, 2018 at 04:45:04AM +0000, Richard Zhu wrote:
> > Assertion of the MSI Enable bit of RC's MSI CAP is mandatory required
> > to trigger MSI on i.MX6 PCIe.
> > This bit would be asserted when CONFIG_PCIEPORTBUS=y.
> > Thus, the MSI works fine on i.MX6 PCIe before the commit "f3fdfc4".
> >
> > Assert it unconditionally when MSI is enabled.
> > Otherwise, the MSI wouldn't be triggered although the EP is present
> > and the MSIs are assigned.
> >
> > Signed-off-by: Richard Zhu <hongxing.zhu@....com>
> > Reviewed-by: Lucas Stach <l.stach@...gutronix.de>
> > ---
> > Changes v1 -> v2:
> > * Assert the MSI_EN unconditionally when MSI is supported.
> > Changes v2 -> v3:
> > * Remove the IS_ENABLED(CONFIG_PCI_MSI) since the driver depends on
> > PCI_MSI_IRQ_DOMAIN
> > * Extended with a check for pci_msi_enabled() to see if the user
> > explicitly want legacy IRQs Changes v3 -> v4:
> > * Refer to Bjorn's comments, refine the subject and commit log and
> > change the PCI_MSI_CAP to PCIE_RC_IMX6_MSI_CAP.
> > Changes v4 -> v5:
> > * Correct one spell mistake from PCIE_RC_MSI_IMX6_CAP to
> > PCIE_RC_IMX6_MSI_CAP.
> > ---
> >  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 e563ca9..73542dd 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -82,6 +82,7 @@ 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
> > @@ -999,6 +1000,7 @@ 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)
> > @@ -1149,6 +1151,14 @@ 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;
> >  }
> 
> Hi Richard,
> 
> the patch is OK with me (even though I have to take for granted how the IMX
> MSI logic works), the commit log isn't. So please update it with Bjorn's version:
> 
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.
> kernel.org%2Flinux-pci%2F20181219141241.GB12763%40google.com%2F&a
> mp;data=02%7C01%7Chongxing.zhu%40nxp.com%7C8d4c31272e9f41298ea
> 908d6668a6f47%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63
> 6809142093459437&amp;sdata=fKpSC2L8TpC217ef4uXLX%2FylvnrCwp38Ug
> n8bMWvjO8%3D&amp;reserved=0
> 
> *inclusive* of the Fixes: tag.
> 
> With the commit log updated as per the link above:
> 
> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
[Richard Zhu] Thanks. I would send out next version with Bjorn's commits later.