[PATCH v5 3/8] PCI: keystone: Use hwirq to get the MSI IRQ number offset

[Kishon Vijay Abraham I]

ks_pcie_msi_irq_handler() uses 'virq' to get the IRQ number offset.
This offset is used to get the correct MSI_IRQ_STATUS register
corresponding to the IRQ line that raised the interrupt.
There is no guarantee that 'virq' assigned for consecutive hardware
IRQ will be contiguous. And this might get us an incorrect IRQ number
offset.

Fix it here by using 'hwirq' to get the IRQ number offset. Since we
don't store the 'virq' numbers of all the IRQ numbers, stop checking
if irq count is greater than MAX_MSI_HOST_IRQS and remove
MAX_MSI_HOST_IRQS.

Link: https://lkml.kernel.org/r/bb081d21-7c03-0357-4294-7e92d95d838c@xxxxxxx
Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
---
 drivers/pci/controller/dwc/pci-keystone.c | 24 ++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
index 47f0dcf638f2..fce25a0dcd08 100644
--- a/drivers/pci/controller/dwc/pci-keystone.c
+++ b/drivers/pci/controller/dwc/pci-keystone.c
@@ -74,7 +74,6 @@
 #define ERR_IRQ_ALL			(ERR_AER | ERR_AXI | ERR_CORR | \
 					 ERR_NONFATAL | ERR_FATAL | ERR_SYS)
 
-#define MAX_MSI_HOST_IRQS		8
 /* PCIE controller device IDs */
 #define PCIE_RC_K2HK			0xb008
 #define PCIE_RC_K2E			0xb009
@@ -90,7 +89,7 @@ struct keystone_pcie {
 	int			legacy_host_irqs[PCI_NUM_INTX];
 	struct			device_node *legacy_intc_np;
 
-	int			msi_host_irqs[MAX_MSI_HOST_IRQS];
+	int			msi_host_irq;
 	int			num_lanes;
 	u32			num_viewport;
 	struct phy		**phy;
@@ -553,9 +552,9 @@ static int ks_pcie_establish_link(struct keystone_pcie *ks_pcie)
 
 static void ks_pcie_msi_irq_handler(struct irq_desc *desc)
 {
-	unsigned int irq = irq_desc_get_irq(desc);
+	unsigned int irq = desc->irq_data.hwirq;
 	struct keystone_pcie *ks_pcie = irq_desc_get_handler_data(desc);
-	u32 offset = irq - ks_pcie->msi_host_irqs[0];
+	u32 offset = irq - ks_pcie->msi_host_irq;
 	struct dw_pcie *pci = ks_pcie->pci;
 	struct device *dev = pci->dev;
 	struct irq_chip *chip = irq_desc_get_chip(desc);
@@ -606,6 +605,7 @@ static int ks_pcie_config_msi_irq(struct keystone_pcie *ks_pcie)
 	struct device *dev = ks_pcie->pci->dev;
 	struct device_node *np = ks_pcie->np;
 	struct device_node *intc_np;
+	struct irq_data *irq_data;
 	int irq_count, irq, ret, i;
 
 	if (!IS_ENABLED(CONFIG_PCI_MSI))
@@ -624,19 +624,21 @@ static int ks_pcie_config_msi_irq(struct keystone_pcie *ks_pcie)
 		goto err;
 	}
 
-	if (irq_count > MAX_MSI_HOST_IRQS) {
-		dev_warn(dev, "Too many MSI interrupt lines defined %u\n",
-			 irq_count);
-		irq_count = MAX_MSI_HOST_IRQS;
-	}
-
 	for (i = 0; i < irq_count; i++) {
 		irq = irq_of_parse_and_map(intc_np, i);
 		if (!irq) {
 			ret = -EINVAL;
 			goto err;
 		}
-		ks_pcie->msi_host_irqs[i] = irq;
+
+		if (!ks_pcie->msi_host_irq) {
+			irq_data = irq_get_irq_data(irq);
+			if (!irq_data) {
+				ret = -EINVAL;
+				goto err;
+			}
+			ks_pcie->msi_host_irq = irq_data->hwirq;
+		}
 
 		irq_set_chained_handler_and_data(irq, ks_pcie_msi_irq_handler,
 						 ks_pcie);
-- 
2.17.1