[PATCH v3 2/5] PCI: dwc: Teach dwc core to parse additional MSI interrupts

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

DWC driver parses a single "msi" interrupt which gets fired when the EP
sends an MSI interrupt, however for some devices (Qualcomm) MSI vectors
are handled in groups by 32 vectors in each group. Add support for
parsing "split" MSI interrupts.

In addition to the "msi" interrupt, the code will lookup the "msi2",
"msi3", etc. IRQs and use them for the MSI group interrupts. For
backwards compatibility with existing DTS files, the code will not error
out if these interrupts are missing. Instead it will limit itself
to the number of MSI group IRQs declared in the DT file.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 .../pci/controller/dwc/pcie-designware-host.c | 23 +++++++++++++++++++
 drivers/pci/controller/dwc/pcie-designware.h  |  1 +
 2 files changed, 24 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 5d90009a0f73..ce7071095006 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -382,6 +382,29 @@ int dw_pcie_host_init(struct pcie_port *pp)
 				pp->msi_irq[0] = irq;
 			}
 
+			if (pp->has_split_msi_irq) {
+				char irq_name[] = "msiXXX";
+				int irq;
+
+				for (ctrl = 1; ctrl < num_ctrls; ctrl++) {
+					if (pp->msi_irq[ctrl])
+						continue;
+
+					snprintf(irq_name, sizeof(irq_name), "msi%d", ctrl + 1);
+					irq = platform_get_irq_byname_optional(pdev, irq_name);
+					if (irq == -ENXIO) {
+						num_ctrls = ctrl;
+						pp->num_vectors = num_ctrls * MAX_MSI_IRQS_PER_CTRL;
+						dev_warn(dev, "Limiting amount of MSI irqs to %d\n", pp->num_vectors);
+						break;
+					}
+					if (irq < 0)
+						return irq;
+
+					pp->msi_irq[ctrl] = irq;
+				}
+			}
+
 			pp->msi_irq_chip = &dw_pci_msi_bottom_irq_chip;
 
 			ret = dw_pcie_allocate_domains(pp);
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