> Subject: [PATCH v3 2/6] PCI: xilinx: Unify INTx & MSI interrupt FIFO decode
>
> When decoding either an INTx or MSI interrupt, the driver has no way to
> know which it will pull out of the interrupt FIFO. If both were pending then
> this would lead to either the interrupt being handled incorrectly (MSI
> interrupt treated as INTx) or not at all (INTx interrupt dropped by MSI path).
> Unify the reading of the interrupt FIFO & act according to the type of
> interrupt actually read.
>
> Signed-off-by: Paul Burton <paul.bur...@imgtec.com>
> Fixes: 8961def56845 ("PCI: xilinx: Add Xilinx AXI PCIe Host Bridge IP driver")
>
> ---
>
> Changes in v3:
> - Split out from Boston patchset.
>
> Changes in v2:
> - Add Fixes tag.
>
> drivers/pci/host/pcie-xilinx.c | 47
> +++++++++++++-----------------------------
> 1 file changed, 14 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/pci/host/pcie-xilinx.c b/drivers/pci/host/pcie-xilinx.c
> index
> 1490bd1..afdfb09 100644
> --- a/drivers/pci/host/pcie-xilinx.c
> +++ b/drivers/pci/host/pcie-xilinx.c
> @@ -397,7 +397,7 @@ static const struct irq_domain_ops intx_domain_ops
> = { static irqreturn_t xilinx_pcie_intr_handler(int irq, void *data) {
> struct xilinx_pcie_port *port = (struct xilinx_pcie_port *)data;
> - u32 val, mask, status, msi_data;
> + u32 val, mask, status;
>
> /* Read interrupt decode and mask registers */
> val = pcie_read(port, XILINX_PCIE_REG_IDR); @@ -437,8 +437,8 @@
> static irqreturn_t xilinx_pcie_intr_handler(int irq, void *data)
> xilinx_pcie_clear_err_interrupts(port);
> }
>
> - if (status & XILINX_PCIE_INTR_INTX) {
> - /* INTx interrupt received */
> + if (status & (XILINX_PCIE_INTR_INTX | XILINX_PCIE_INTR_MSI)) {
> + /* Interrupt received */
> val = pcie_read(port, XILINX_PCIE_REG_RPIFR1);
>
> /* Check whether interrupt valid */
> @@ -447,41 +447,22 @@ static irqreturn_t xilinx_pcie_intr_handler(int irq,
> void *data)
> return IRQ_HANDLED;
> }
>
> - if (!(val & XILINX_PCIE_RPIFR1_MSI_INTR)) {
> - /* Clear interrupt FIFO register 1 */
> - pcie_write(port, XILINX_PCIE_RPIFR1_ALL_MASK,
> - XILINX_PCIE_REG_RPIFR1);
> -
> - /* Handle INTx Interrupt */
> + if (val & XILINX_PCIE_RPIFR1_MSI_INTR) {
> + irq = pcie_read(port, XILINX_PCIE_REG_RPIFR2) &
> + XILINX_PCIE_RPIFR2_MSG_DATA;
> + } else {
> val = ((val & XILINX_PCIE_RPIFR1_INTR_MASK) >>
> XILINX_PCIE_RPIFR1_INTR_SHIFT) + 1;
> - generic_handle_irq(irq_find_mapping(port-
> >irq_domain,
> - val));
> + irq = irq_find_mapping(port->irq_domain, val);
> }
> - }
>
> - if (status & XILINX_PCIE_INTR_MSI) {
> - /* MSI Interrupt */
> - val = pcie_read(port, XILINX_PCIE_REG_RPIFR1);
> + /* Clear interrupt FIFO register 1 */
> + pcie_write(port, XILINX_PCIE_RPIFR1_ALL_MASK,
> + XILINX_PCIE_REG_RPIFR1);
>
> - if (!(val & XILINX_PCIE_RPIFR1_INTR_VALID)) {
> - dev_warn(port->dev, "RP Intr FIFO1 read error\n");
> - return IRQ_HANDLED;
> - }
> -
> - if (val & XILINX_PCIE_RPIFR1_MSI_INTR) {
> - msi_data = pcie_read(port,
> XILINX_PCIE_REG_RPIFR2) &
> - XILINX_PCIE_RPIFR2_MSG_DATA;
> -
> - /* Clear interrupt FIFO register 1 */
> - pcie_write(port, XILINX_PCIE_RPIFR1_ALL_MASK,
> - XILINX_PCIE_REG_RPIFR1);
> -
> - if (IS_ENABLED(CONFIG_PCI_MSI)) {
> - /* Handle MSI Interrupt */
> - generic_handle_irq(msi_data);
> - }
> - }
> + if (IS_ENABLED(CONFIG_PCI_MSI) ||
> + !(val & XILINX_PCIE_RPIFR1_MSI_INTR))
> + generic_handle_irq(irq);
> }
>
> if (status & XILINX_PCIE_INTR_SLV_UNSUPP)
> --
Hi Paul,
Even with above condition you are still missing either MSI or legacy interrupt
handling, when both MSI and legacy interrupts occurred.
Bharat
