[PATCH v6 4/7] PCI: dwc: Export several functions useful for MSI implentations

[Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>]

Supporting multiple MSI interrupts on Qualcomm hardware would benefit
from having these functions being exported rather than static. Note that
both designware and qcom driver can not be built as modules, so no need
to use EXPORT_SYMBOL here.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
---
 .../pci/controller/dwc/pcie-designware-host.c | 62 ++++++++++++-------
 drivers/pci/controller/dwc/pcie-designware.h  | 11 ++++
 2 files changed, 49 insertions(+), 24 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 92dcaeabe2bf..c3b8ab278a00 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -255,7 +255,39 @@ int dw_pcie_allocate_domains(struct pcie_port *pp)
 	return 0;
 }
 
-static void dw_pcie_free_msi(struct pcie_port *pp)
+int dw_pcie_allocate_msi(struct pcie_port *pp)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	int ret;
+
+	ret = dw_pcie_allocate_domains(pp);
+	if (ret)
+		return ret;
+
+	if (pp->msi_irq > 0)
+		irq_set_chained_handler_and_data(pp->msi_irq,
+				dw_chained_msi_isr,
+				pp);
+
+	ret = dma_set_mask(pci->dev, DMA_BIT_MASK(32));
+	if (ret)
+		dev_warn(pci->dev, "Failed to set DMA mask to 32-bit. Devices with only 32-bit MSI support may not work properly\n");
+
+	pp->msi_data = dma_map_single_attrs(pci->dev, &pp->msi_msg,
+			sizeof(pp->msi_msg),
+			DMA_FROM_DEVICE,
+			DMA_ATTR_SKIP_CPU_SYNC);
+	ret = dma_mapping_error(pci->dev, pp->msi_data);
+	if (ret) {
+		dev_err(pci->dev, "Failed to map MSI data\n");
+		pp->msi_data = 0;
+		return ret;
+	}
+
+	return 0;
+}
+
+void dw_pcie_free_msi(struct pcie_port *pp)
 {
 	if (pp->msi_irq > 0)
 		irq_set_chained_handler_and_data(pp->msi_irq, NULL, NULL);
@@ -357,6 +389,9 @@ int dw_pcie_host_init(struct pcie_port *pp)
 			return -EINVAL;
 		}
 
+		/* this can be overridden by msi_host_init() if necessary */
+		pp->msi_irq_chip = &dw_pci_msi_bottom_irq_chip;
+
 		if (pp->ops->msi_host_init) {
 			ret = pp->ops->msi_host_init(pp);
 			if (ret < 0)
@@ -377,30 +412,9 @@ int dw_pcie_host_init(struct pcie_port *pp)
 				}
 			}
 
-			pp->msi_irq_chip = &dw_pci_msi_bottom_irq_chip;
-
-			ret = dw_pcie_allocate_domains(pp);
-			if (ret)
+			ret = dw_pcie_allocate_msi(pp);
+			if (ret < 0)
 				return ret;
-
-			if (pp->msi_irq > 0)
-				irq_set_chained_handler_and_data(pp->msi_irq,
-							    dw_chained_msi_isr,
-							    pp);
-
-			ret = dma_set_mask(pci->dev, DMA_BIT_MASK(32));
-			if (ret)
-				dev_warn(pci->dev, "Failed to set DMA mask to 32-bit. Devices with only 32-bit MSI support may not work properly\n");
-
-			pp->msi_data = dma_map_single_attrs(pci->dev, &pp->msi_msg,
-						      sizeof(pp->msi_msg),
-						      DMA_FROM_DEVICE,
-						      DMA_ATTR_SKIP_CPU_SYNC);
-			if (dma_mapping_error(pci->dev, pp->msi_data)) {
-				dev_err(pci->dev, "Failed to map MSI data\n");
-				pp->msi_data = 0;
-				goto err_free_msi;
-			}
 		}
 	}
 
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index e1c48b71e0d2..f72447f15dc5 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -374,6 +374,8 @@ void dw_pcie_host_deinit(struct pcie_port *pp);
 int dw_pcie_allocate_domains(struct pcie_port *pp);
 void __iomem *dw_pcie_own_conf_map_bus(struct pci_bus *bus, unsigned int devfn,
 				       int where);
+int dw_pcie_allocate_msi(struct pcie_port *pp);
+void dw_pcie_free_msi(struct pcie_port *pp);
 #else
 static inline irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
 {
@@ -403,6 +405,15 @@ static inline void __iomem *dw_pcie_own_conf_map_bus(struct pci_bus *bus,
 {
 	return NULL;
 }
+
+static int dw_pcie_allocate_msi(struct pcie_port *pp)
+{
+	return -EINVAL;
+}
+
+static void dw_pcie_free_msi(struct pcie_port *pp)
+{
+}
 #endif
 
 #ifdef CONFIG_PCIE_DW_EP
-- 
2.35.1