Friendly ping.
Anymore comments are very appreciated.
BTW, I had verified on i.MX7D/i.MX6QP platforms that MSI wouldn’t be functional
after resume without this patch.
Best Regards
Richard Zhu
> -----Original Message-----
> From: Richard Zhu <hongxing.zhu@xxxxxxx>
> Sent: 2022年11月1日 16:00
> To: l.stach@xxxxxxxxxxxxxx; bhelgaas@xxxxxxxxxx;
> lorenzo.pieralisi@xxxxxxx
> Cc: Hongxing Zhu <hongxing.zhu@xxxxxxx>; linux-pci@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> kernel@xxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>
> Subject: [PATCH v1] PCI: imx6: Set MSI enable bit of RC in resume
>
> The MSI Enable bit controls delivery of MSI interrupts from components below
> the Root Port. This bit might lost during the suspend, should be re-configured
> during resume.
>
> Encapsulate the MSI enable set into a standalone function, and invoke it in
> both probe and resume.
>
> Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> ---
> drivers/pci/controller/dwc/pci-imx6.c | 24 +++++++++++++++++-------
> 1 file changed, 17 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> b/drivers/pci/controller/dwc/pci-imx6.c
> index 2616585ca5f8..dba15546075f 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -1041,6 +1041,21 @@ static void imx6_pcie_pm_turnoff(struct
> imx6_pcie *imx6_pcie)
> usleep_range(1000, 10000);
> }
>
> +static void pci_imx_set_msi_en(struct dw_pcie *pci) {
> + u8 offset;
> + u16 val;
> +
> + if (pci_msi_enabled()) {
> + offset = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
> + dw_pcie_dbi_ro_wr_en(pci);
> + val = dw_pcie_readw_dbi(pci, offset + PCI_MSI_FLAGS);
> + val |= PCI_MSI_FLAGS_ENABLE;
> + dw_pcie_writew_dbi(pci, offset + PCI_MSI_FLAGS, val);
> + dw_pcie_dbi_ro_wr_dis(pci);
> + }
> +}
> +
> static int imx6_pcie_suspend_noirq(struct device *dev) {
> struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev); @@ -1073,6
> +1088,7 @@ static int imx6_pcie_resume_noirq(struct device *dev)
> if (imx6_pcie->link_is_up)
> imx6_pcie_start_link(imx6_pcie->pci);
>
> + pci_imx_set_msi_en(imx6_pcie->pci);
> return 0;
> }
>
> @@ -1090,7 +1106,6 @@ 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)
> @@ -1282,12 +1297,7 @@ static int imx6_pcie_probe(struct platform_device
> *pdev)
> if (ret < 0)
> return ret;
>
> - if (pci_msi_enabled()) {
> - u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
> - val = dw_pcie_readw_dbi(pci, offset + PCI_MSI_FLAGS);
> - val |= PCI_MSI_FLAGS_ENABLE;
> - dw_pcie_writew_dbi(pci, offset + PCI_MSI_FLAGS, val);
> - }
> + pci_imx_set_msi_en(pci);
>
> return 0;
> }
> --
> 2.25.1
