PCI: qcom-ep: Add eDMA support

Qualcomm PCIe Endpoint controllers have the in-built Embedded DMA (eDMA)
peripheral for offloading the data transfer between the PCIe bus and
memory.

Let's add support for it by enabling the eDMA IRQ in the driver. The
eDMA DMA Engine driver will handle the rest of the functionality.

Since the eDMA on Qualcomm platforms only uses a single IRQ for all
channels, use 1 for edma.nr_irqs.

[kwilczynski: commit log]
Link: https://lore.kernel.org/linux-pci/20230717065459.14138-4-manivannan.sadhasivam@linaro.orgSigned-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>

drivers/pci/controller/dwc/pcie-qcom-ep.c

@@ -74,6 +74,7 @@
 #define PARF_INT_ALL_PLS_ERR			BIT(15)
 #define PARF_INT_ALL_PME_LEGACY			BIT(16)
 #define PARF_INT_ALL_PLS_PME			BIT(17)
+#define PARF_INT_ALL_EDMA			BIT(22)
 
 /* PARF_BDF_TO_SID_CFG register fields */
 #define PARF_BDF_TO_SID_BYPASS			BIT(0)
@@ -395,7 +396,7 @@ static int qcom_pcie_perst_deassert(struct dw_pcie *pci)
 	writel_relaxed(0, pcie_ep->parf + PARF_INT_ALL_MASK);
 	val = PARF_INT_ALL_LINK_DOWN | PARF_INT_ALL_BME |
 	      PARF_INT_ALL_PM_TURNOFF | PARF_INT_ALL_DSTATE_CHANGE |
-	      PARF_INT_ALL_LINK_UP;
+	      PARF_INT_ALL_LINK_UP | PARF_INT_ALL_EDMA;
 	writel_relaxed(val, pcie_ep->parf + PARF_INT_ALL_MASK);
 
 	ret = dw_pcie_ep_init_complete(&pcie_ep->pci.ep);
@@ -744,6 +745,7 @@ static int qcom_pcie_ep_probe(struct platform_device *pdev)
 	pcie_ep->pci.dev = dev;
 	pcie_ep->pci.ops = &pci_ops;
 	pcie_ep->pci.ep.ops = &pci_ep_ops;
+	pcie_ep->pci.edma.nr_irqs = 1;
 	platform_set_drvdata(pdev, pcie_ep);
 
 	ret = qcom_pcie_ep_get_resources(pdev, pcie_ep);