Re: [PATCH] PCI: imx: make msi work without pcieportbus

From: Baruch Siach
Date: Thu Dec 13 2018 - 01:36:58 EST


Hi Richard,

Thanks for debugging this issue. One question below.

Richard Zhu writes:
> MSI_EN of iMX PCIe RC would be asserted when
> PCIEPORTBUS driver is selected.
> Thus, the MSI works fine on iMX PCIe before.
> Make a double check on this bit, and assert it
> when it is not set and MSI is supported.
> Otherwise, the MSI wouldn't be triggered although
> the EP is present and the MSIs are assigned.
>
> Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> ---
> 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 26087b3..6c3e56b 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 +1072,14 @@ 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);
> + if ((val & PCI_MSI_FLAGS_ENABLE) == 0) {
> + val |= PCI_MSI_FLAGS_ENABLE;

Why not assert the PCI_MSI_FLAGS_ENABLE flag unconditionally here?

> + dw_pcie_writew_dbi(pci, PCI_MSI_CAP +
> + PCI_MSI_FLAGS, val);
> + }
> + }
>
> return 0;
> }

baruch

--
http://baruch.siach.name/blog/ ~. .~ Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
- baruch@xxxxxxxxxx - tel: +972.52.368.4656, http://www.tkos.co.il -