[PATCH 4/4] PCI: dwc: pci-dra7xx: Fix legacy IRQ handling

[Vignesh R]

Legacy INTD IRQ handling is broken on dra7xx due to fact that driver
uses hwirq in range of 1-4 for INTA, INTD whereas IRQ domain is of size
4 which is numbered 0-3. Therefore when INTD IRQ line is used with
pci-dra7xx driver following warning is seen:

       WARNING: CPU: 0 PID: 1 at kernel/irq/irqdomain.c:342 
irq_domain_associate+0x12c/0x1c4
       error: hwirq 0x4 is too large for dummy

Fix this by using pci_irqd_intx_xlate() helper to translate the INTx 1-4
range into the 0-3 as done in other PCIe drivers.

Also, iterate over all the INTx bits and call their respective IRQ
handlers before clearing the status register.

Suggested-by: Bjorn Helgaas <bhelg...@google.com>
Reported-by: Chris Welch <chris.we...@viavisolutions.com>
Signed-off-by: Vignesh R <vigne...@ti.com>
---
 drivers/pci/dwc/pci-dra7xx.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/dwc/pci-dra7xx.c b/drivers/pci/dwc/pci-dra7xx.c
index 53f721d1cc40..59e8de34cec6 100644
--- a/drivers/pci/dwc/pci-dra7xx.c
+++ b/drivers/pci/dwc/pci-dra7xx.c
@@ -226,6 +226,7 @@ static int dra7xx_pcie_intx_map(struct irq_domain *domain, 
unsigned int irq,
 
 static const struct irq_domain_ops intx_domain_ops = {
        .map = dra7xx_pcie_intx_map,
+       .xlate = pci_irqd_intx_xlate,
 };
 
 static int dra7xx_pcie_init_irq_domain(struct pcie_port *pp)
@@ -256,7 +257,8 @@ static irqreturn_t dra7xx_pcie_msi_irq_handler(int irq, 
void *arg)
        struct dra7xx_pcie *dra7xx = arg;
        struct dw_pcie *pci = dra7xx->pci;
        struct pcie_port *pp = &pci->pp;
-       u32 reg;
+       unsigned long reg;
+       u32 virq, bit;
 
        reg = dra7xx_pcie_readl(dra7xx, PCIECTRL_DRA7XX_CONF_IRQSTATUS_MSI);
 
@@ -268,8 +270,11 @@ static irqreturn_t dra7xx_pcie_msi_irq_handler(int irq, 
void *arg)
        case INTB:
        case INTC:
        case INTD:
-               generic_handle_irq(irq_find_mapping(dra7xx->irq_domain,
-                                                   ffs(reg)));
+               for_each_set_bit(bit, &reg, PCI_NUM_INTX) {
+                       virq = irq_find_mapping(dra7xx->irq_domain, bit);
+                       if (virq)
+                               generic_handle_irq(virq);
+               }
                break;
        }
 
-- 
2.15.0