This was a multi-part message with HTML, which I think causes the
mailing list to automatically drop it. Please post this as plain text
with a changelog and signed-off-by and copy the DesignWare maintainers
(Jingoo and Joao, cc'd).
On Tue, Aug 1, 2017 at 12:28 AM, vidya sagar <sagar.tv@xxxxxxxxx> wrote:
> Hi,
> As you might be knowing it already, in the current pcie-designware.c , there
> is no support for MSI-X
> Although there is no native support from Synopsys IP as well to have 2048
> interrupts, we can at least have basic support to get MSI-X also allocated
> (along with MSI) as many as possible in the system at that point. Of course,
> all these interrupts will have the same address to which downstream devices
> need to initiate mem-write transactions. Though it doesn't leverage one of
> the advantages of having MSI-X over MSI, it at least avoids drivers falling
> back to legacy interrupts when the card doesn't support MSI. Some of the
> Intel NVMe cards are examples here. Legacy interrupt being a shared
> interrupt, it unnecessarily triggers all other shared ISRs to be called
> whenever there is a legacy interrupt.
>
> I have the following patch which enables MSI-X support also. Would like to
> have your comments on this.
>
>
> diff --git a/drivers/pci/host/pcie-designware.c
> b/drivers/pci/host/pcie-designware.c
> index af8f6e9..9086253 100644
> --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -406,9 +406,6 @@ static int dw_msi_setup_irq(struct msi_controller *chip,
> struct pci_dev *pdev,
> int irq, pos;
> struct pcie_port *pp = pdev->bus->sysdata;
>
> - if (desc->msi_attrib.is_msix)
> - return -EINVAL;
> -
> irq = assign_irq(1, desc, &pos);
> if (irq < 0)
> return irq;
> @@ -426,9 +423,16 @@ static int dw_msi_setup_irqs(struct msi_controller
> *chip, struct pci_dev *pdev,
> struct msi_desc *desc;
> struct pcie_port *pp = pdev->bus->sysdata;
>
> - /* MSI-X interrupts are not supported */
> - if (type == PCI_CAP_ID_MSIX)
> - return -EINVAL;
> + if (type == PCI_CAP_ID_MSIX) {
> + for_each_pci_msi_entry(desc, pdev) {
> + irq = arch_setup_msi_irq(pdev, desc);
> + if (irq < 0)
> + return irq;
> + if (irq > 0)
> + return -ENOSPC;
> + }
> + return 0;
> + }
>
> WARN_ON(!list_is_singular(&pdev->dev.msi_list));
> desc = list_entry(pdev->dev.msi_list.next, struct msi_desc, list);
>
