[PATCH v9 06/10] PCI: dwc: Handle MSIs routed to multiple GIC interrupts

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

On some of Qualcomm platforms each group of 32 MSI vectors is routed to the
separate GIC interrupt. Implement support for such configurations by
parsing "msi0" ... "msiN" interrupts and attaching them to the chained
handler.

Note, that if DT doesn't list an array of MSI interrupts and uses single
"msi" IRQ, the driver will limit the amount of supported MSI vectors
accordingly (to 32).

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 .../pci/controller/dwc/pcie-designware-host.c | 34 +++++++++++++++++--
 drivers/pci/controller/dwc/pcie-designware.h  |  1 +
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 983fff735d7e..007600524b49 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -291,7 +291,8 @@ static void dw_pcie_msi_init(struct pcie_port *pp)
 static int dw_pcie_msi_host_init(struct pcie_port *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
-	struct platform_device *pdev = to_platform_device(pci->dev);
+	struct device *dev = pci->dev;
+	struct platform_device *pdev = to_platform_device(dev);
 	int ret;
 	u32 ctrl, num_ctrls;
 
@@ -299,13 +300,42 @@ static int dw_pcie_msi_host_init(struct pcie_port *pp)
 	for (ctrl = 0; ctrl < num_ctrls; ctrl++)
 		pp->irq_mask[ctrl] = ~0;
 
+	if (pp->has_split_msi_irq) {
+		char irq_name[] = "msiXX";
+		int irq;
+
+		for (ctrl = 0; ctrl < num_ctrls; ctrl++) {
+			if (pp->msi_irq[ctrl])
+				continue;
+
+			snprintf(irq_name, sizeof(irq_name), "msi%d", ctrl);
+			irq = platform_get_irq_byname(pdev, irq_name);
+			if (irq == -ENXIO && ctrl == 0) {
+				num_ctrls = 1;
+				pp->num_vectors = min_t(u32,
+							MAX_MSI_IRQS_PER_CTRL,
+							pp->num_vectors);
+				dev_warn(dev, "No split MSI IRQs, fallback to single MSI IRQ\n");
+				break;
+			} else if (irq < 0) {
+				return dev_err_probe(dev, irq,
+						     "Failed to parse MSI IRQ '%s'\n",
+						     irq_name);
+			}
+
+			pp->msi_irq[ctrl] = irq;
+		}
+
+		dev_info(dev, "Using %d MSI vectors\n", pp->num_vectors);
+	}
+
 	if (!pp->msi_irq[0]) {
 		int irq = platform_get_irq_byname_optional(pdev, "msi");
 
 		if (irq < 0) {
 			irq = platform_get_irq(pdev, 0);
 			if (irq < 0)
-				return irq;
+				return dev_err_probe(dev, irq, "Failed to parse MSI irq\n");
 		}
 		pp->msi_irq[0] = irq;
 	}
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 9c1a38b0a6b3..3aa840a5b19c 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -179,6 +179,7 @@ struct dw_pcie_host_ops {
 
 struct pcie_port {
 	bool			has_msi_ctrl:1;
+	bool			has_split_msi_irq:1;
 	u64			cfg0_base;
 	void __iomem		*va_cfg0_base;
 	u32			cfg0_size;
-- 
2.35.1