From b5fecc5ff8bdf349d57776f14c493c8d42012a99 Mon Sep 17 00:00:00 2001
From: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Date: Tue, 16 Mar 2021 09:01:28 +0100
Subject: [PATCH] drivers/pcie: Add a function for dynamic PCIe IRQ connection

The is meant to fix a chicken & egg issue with MSI interrupt remapping.
Currently, drivers first connect the irq (by-passing any possible MSI
remapping), so the IRQ ends-up being remapped at the IOAPIC level which
is not what we want.

So adding a dedicated function to properly handle this case. This is
valid only for runtime dynamic IRQ connection obviously.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
---
 drivers/pcie/host/pcie.c    | 29 +++++++++++++++++++++++++++++
 include/drivers/pcie/pcie.h | 18 ++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/drivers/pcie/host/pcie.c b/drivers/pcie/host/pcie.c
index 8626e127bc0..f6fb38142ef 100644
--- a/drivers/pcie/host/pcie.c
+++ b/drivers/pcie/host/pcie.c
@@ -252,6 +252,35 @@ unsigned int pcie_get_irq(pcie_bdf_t bdf)
 	return PCIE_CONF_INTR_IRQ(data);
 }
 
+bool pcie_connect_dynamic_irq(pcie_bdf_t bdf,
+			      unsigned int irq,
+			      unsigned int priority,
+			      void (*routine)(const void *parameter),
+			      const void *parameter,
+			      uint32_t flags)
+{
+#if defined(CONFIG_PCIE_MSI) && defined(CONFIG_PCIE_MSI_MULTI_VECTOR)
+	if (pcie_is_msi(bdf)) {
+		msi_vector_t vector;
+
+		if ((pcie_msi_vectors_allocate(bdf, priority,
+					       &vector, 1) == 0) ||
+		    !pcie_msi_vector_connect(bdf, &vector,
+					     routine, parameter, flags)) {
+			return false;
+		}
+	} else
+#endif /* CONFIG_PCIE_MSI && CONFIG_PCIE_MSI_MULTI_VECTOR */
+	{
+		if (irq_connect_dynamic(irq, priority, routine,
+					parameter, flags) < 0) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
 void pcie_irq_enable(pcie_bdf_t bdf, unsigned int irq)
 {
 #if CONFIG_PCIE_MSI
diff --git a/include/drivers/pcie/pcie.h b/include/drivers/pcie/pcie.h
index 785e31ab0b8..76c1afc94ff 100644
--- a/include/drivers/pcie/pcie.h
+++ b/include/drivers/pcie/pcie.h
@@ -181,6 +181,24 @@ extern uint32_t pcie_get_cap(pcie_bdf_t bdf, uint32_t cap_id);
  */
 extern uint32_t pcie_get_ext_cap(pcie_bdf_t bdf, uint32_t cap_id);
 
+/**
+ * @brief Dynamically connect a PCIe endpoint IRQ to an ISR handler
+ *
+ * @param bdf the PCI endpoint to examine
+ * @param irq the IRQ to connect (see pcie_alloc_irq())
+ * @param priority priority of the IRQ
+ * @param routine the ISR handler to connect to the IRQ
+ * @param parameter the parameter to provide to the handler
+ * @param flags IRQ connection flags
+ * @return true if connected, false otherwise
+ */
+extern bool pcie_connect_dynamic_irq(pcie_bdf_t bdf,
+				     unsigned int irq,
+				     unsigned int priority,
+				     void (*routine)(const void *parameter),
+				     const void *parameter,
+				     uint32_t flags);
+
 /*
  * Configuration word 13 contains the head of the capabilities list.
  */