staging: mt7621-pci: fix PCIe interrupt mapping

MT7621 has three assigned interrupts for the pcie. This
interrupts should properly being mapped taking into account
which devices are finally connected in which bus according
to link status. So the irq mappings should be as follows
according to link status (three bits indicating which devices
are link up):

* For PCIe Bus 1 slot 0:
  - status = 0x2 || status = 0x6 => IRQ = pcie1_irq (24).
  - status = 0x4 => IRQ = pcie2_irq (25).
  - default => IRQ = pcie0_irq (23).
* For PCIe Bus 2 slot 0:
  - status = 0x5 || status = 0x6 => IRQ = pcie2_irq (25).
  - default => IRQ = pcie1_irq (24).
* For PCIe Bus 2 slot 1:
  - status = 0x5 || status = 0x6 => IRQ = pcie2_irq (25).
  - default => IRQ = pcie1_irq (24).
* For PCIe Bus 3 any slot:
  - default => IRQ = pcie2_irq (25).

Because of this, the function 'of_irq_parse_and_map_pci' cannot
be used and we need to change device tree information from using
the 'interrupt-map' and 'interrupt-map-mask' properties into an
'interrupts' property to be able to get irq information from the
ports using the 'platform_get_irq' and storing an 'irq-map' into
the pcie driver data node to properly map correct irq using a
new 'mt7621_map_irq' function where this map will be read and the
correct irq returned.

Fixes: 46d093124d ("staging: mt7621-pci: improve interrupt mapping")
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20200413055942.2714-1-sergio.paracuellos@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-dts/mt7621.dtsi

@@ -523,11 +523,10 @@
 			0x01000000 0 0x00000000 0x1e160000 0 0x00010000 /* io space */
 		>;
 
-		#interrupt-cells = <1>;
-		interrupt-map-mask = <0xF0000 0 0 1>;
-		interrupt-map = <0x10000 0 0 1 &gic GIC_SHARED 4 IRQ_TYPE_LEVEL_HIGH>,
-				<0x20000 0 0 1 &gic GIC_SHARED 24 IRQ_TYPE_LEVEL_HIGH>,
-				<0x30000 0 0 1 &gic GIC_SHARED 25 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-parent = <&gic>;
+		interrupts = <GIC_SHARED 4 IRQ_TYPE_LEVEL_HIGH
+				GIC_SHARED 24 IRQ_TYPE_LEVEL_HIGH
+				GIC_SHARED 25 IRQ_TYPE_LEVEL_HIGH>;
 
 		status = "disabled";
 

drivers/staging/mt7621-pci/pci-mt7621.c

@@ -97,6 +97,7 @@
  * @pcie_rst: pointer to port reset control
  * @gpio_rst: gpio reset
  * @slot: port slot
+ * @irq: GIC irq
  * @enabled: indicates if port is enabled
  */
 struct mt7621_pcie_port {
@@ -107,6 +108,7 @@ struct mt7621_pcie_port {
 	struct reset_control *pcie_rst;
 	struct gpio_desc *gpio_rst;
 	u32 slot;
+	int irq;
 	bool enabled;
 };
 
@@ -120,6 +122,7 @@ struct mt7621_pcie_port {
  * @dev: Pointer to PCIe device
  * @io_map_base: virtual memory base address for io
  * @ports: pointer to PCIe port information
+ * @irq_map: irq mapping info according pcie link status
  * @resets_inverted: depends on chip revision
  * reset lines are inverted.
  */
@@ -135,6 +138,7 @@ struct mt7621_pcie {
 	} offset;
 	unsigned long io_map_base;
 	struct list_head ports;
+	int irq_map[PCIE_P2P_MAX];
 	bool resets_inverted;
 };
 
@@ -279,6 +283,16 @@ static void setup_cm_memory_region(struct mt7621_pcie *pcie)
 	}
 }
 
+static int mt7621_map_irq(const struct pci_dev *pdev, u8 slot, u8 pin)
+{
+	struct mt7621_pcie *pcie = pdev->bus->sysdata;
+	struct device *dev = pcie->dev;
+	int irq = pcie->irq_map[slot];
+
+	dev_info(dev, "bus=%d slot=%d irq=%d\n", pdev->bus->number, slot, irq);
+	return irq;
+}
+
 static int mt7621_pci_parse_request_of_pci_ranges(struct mt7621_pcie *pcie)
 {
 	struct device *dev = pcie->dev;
@@ -330,6 +344,7 @@ static int mt7621_pcie_parse_port(struct mt7621_pcie *pcie,
 {
 	struct mt7621_pcie_port *port;
 	struct device *dev = pcie->dev;
+	struct platform_device *pdev = to_platform_device(dev);
 	struct device_node *pnode = dev->of_node;
 	struct resource regs;
 	char name[10];
@@ -371,6 +386,12 @@ static int mt7621_pcie_parse_port(struct mt7621_pcie *pcie,
 	port->slot = slot;
 	port->pcie = pcie;
 
+	port->irq = platform_get_irq(pdev, slot);
+	if (port->irq < 0) {
+		dev_err(dev, "Failed to get IRQ for PCIe%d\n", slot);
+		return -ENXIO;
+	}
+
 	INIT_LIST_HEAD(&port->list);
 	list_add_tail(&port->list, &pcie->ports);
 
@@ -585,13 +606,15 @@ static int mt7621_pcie_init_virtual_bridges(struct mt7621_pcie *pcie)
 {
 	u32 pcie_link_status = 0;
 	u32 n;
-	int i;
+	int i = 0;
 	u32 p2p_br_devnum[PCIE_P2P_MAX];
+	int irqs[PCIE_P2P_MAX];
 	struct mt7621_pcie_port *port;
 
 	list_for_each_entry(port, &pcie->ports, list) {
 		u32 slot = port->slot;
 
+		irqs[i++] = port->irq;
 		if (port->enabled)
 			pcie_link_status |= BIT(slot);
 	}
@@ -614,6 +637,15 @@ static int mt7621_pcie_init_virtual_bridges(struct mt7621_pcie *pcie)
 		 (p2p_br_devnum[1] << PCIE_P2P_BR_DEVNUM1_SHIFT) |
 		 (p2p_br_devnum[2] << PCIE_P2P_BR_DEVNUM2_SHIFT));
 
+	/* Assign IRQs */
+	n = 0;
+	for (i = 0; i < PCIE_P2P_MAX; i++)
+		if (pcie_link_status & BIT(i))
+			pcie->irq_map[n++] = irqs[i];
+
+	for (i = n; i < PCIE_P2P_MAX; i++)
+		pcie->irq_map[i] = -1;
+
 	return 0;
 }
 
@@ -638,7 +670,7 @@ static int mt7621_pcie_register_host(struct pci_host_bridge *host,
 	host->busnr = pcie->busn.start;
 	host->dev.parent = pcie->dev;
 	host->ops = &mt7621_pci_ops;
-	host->map_irq = of_irq_parse_and_map_pci;
+	host->map_irq = mt7621_map_irq;
 	host->swizzle_irq = pci_common_swizzle;
 	host->sysdata = pcie;