drivers: pcie: Introduce API to look up devices by ID

In some cases we cannot know the BDF up-front, so provide a way to
look it up based on the vendor and device ID.

Signed-off-by: Johan Hedberg <[email protected]>

Author: Johan Hedberg

drivers/pcie/host/pcie.c

@@ -229,3 +229,28 @@ void pcie_irq_enable(pcie_bdf_t bdf, unsigned int irq)
 #endif
 	irq_enable(irq);
 }
+
+pcie_bdf_t pcie_bdf_lookup(pcie_id_t id)
+{
+	int bus, dev, func;
+
+	for (bus = 0; bus <= PCIE_MAX_BUS; bus++) {
+		for (dev = 0; dev <= PCIE_MAX_DEV; dev++) {
+			for (func = 0; func <= PCIE_MAX_FUNC; func++) {
+				pcie_bdf_t bdf = PCIE_BDF(bus, dev, func);
+				uint32_t data;
+
+				data = pcie_conf_read(bdf, PCIE_CONF_ID);
+				if (data == PCIE_ID_NONE) {
+					continue;
+				}
+
+				if (data == id) {
+					return bdf;
+				}
+			}
+		}
+	}
+
+	return PCIE_BDF_NONE;
+}

include/drivers/pcie/pcie.h

@@ -45,6 +45,17 @@ struct pcie_mbar {
  * These functions are arch-, board-, or SoC-specific.
  */
 
+/**
+ * @brief Look up the BDF based on PCI(e) vendor & device ID
+ *
+ * This function is used to look up the BDF for a device given its
+ * vendor and device ID.
+ *
+ * @param id PCI(e) vendor & device ID encoded using PCIE_ID()
+ * @return The BDF for the device, or PCIE_BDF_NONE if it was not found
+ */
+extern pcie_bdf_t pcie_bdf_lookup(pcie_id_t id);
+
 /**
  * @brief Read a 32-bit word from an endpoint's configuration space.
  *

include/dt-bindings/pcie/pcie.h

@@ -35,6 +35,8 @@
 
 #define PCIE_ID_NONE PCIE_ID(0xFFFF, 0xFFFF)
 
+#define PCIE_BDF_NONE 0xFFFFFFFFU
+
 /*
  * Since our internal representation of bus/device/function is arbitrary,
  * we choose the same format employed in the x86 Configuration Address Port: