linux-kernel - Re: [v3] PCI: imx: make msi work without pcieportbus

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Date:   Thu, 13 Dec 2018 11:46:52 +0100
From:   Lucas Stach <l.stach@...gutronix.de>
To:     Richard Zhu <hongxing.zhu@....com>,
        "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
        "lorenzo.pieralisi@....com" <lorenzo.pieralisi@....com>,
        "andrew.smirnov@...il.com" <andrew.smirnov@...il.com>
Cc:     "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: [v3] PCI: imx: make msi work without pcieportbus

Am Donnerstag, den 13.12.2018, 10:43 +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 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
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 26087b3..1c59a93 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)
> @@ -1071,6 +1073,12 @@ static int imx6_pcie_probe(struct platform_device *pdev)
> >  	if (ret < 0)
> >  		return ret;
>  
> > +	if (pci_msi_enabled()) {
> > +		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;
>  }
>