From b07319c849a174a85472144014aa3462f90343e0 Mon Sep 17 00:00:00 2001
From: hselasky <hselasky@FreeBSD.org>
Date: Wed, 14 Aug 2019 09:36:25 +0000
Subject: [PATCH] Implement pci_enable_msi() and pci_disable_msi() in the
 LinuxKPI. This patch makes the DRM graphics driver in ports usable on
 aarch64.

Submitted by:	Greg V <greg@unrelenting.technology>
Differential Revision:	https://reviews.freebsd.org/D21008
MFC after:	1 week
Sponsored by:	Mellanox Technologies
---
 .../linuxkpi/common/include/linux/device.h    |  4 +-
 .../linuxkpi/common/include/linux/interrupt.h |  6 ++-
 .../linuxkpi/common/include/linux/pci.h       | 54 ++++++++++++++++---
 3 files changed, 54 insertions(+), 10 deletions(-)

diff --git a/sys/compat/linuxkpi/common/include/linux/device.h b/sys/compat/linuxkpi/common/include/linux/device.h
index 629ca7b4588..bfbea7c4548 100644
--- a/sys/compat/linuxkpi/common/include/linux/device.h
+++ b/sys/compat/linuxkpi/common/include/linux/device.h
@@ -110,8 +110,8 @@ struct device {
 	void		*driver_data;
 	unsigned int	irq;
 #define	LINUX_IRQ_INVALID	65535
-	unsigned int	msix;
-	unsigned int	msix_max;
+	unsigned int	irq_start;
+	unsigned int	irq_end;
 	const struct attribute_group **groups;
 	struct fwnode_handle *fwnode;
 
diff --git a/sys/compat/linuxkpi/common/include/linux/interrupt.h b/sys/compat/linuxkpi/common/include/linux/interrupt.h
index dac5d5e92cc..6bb5880b6cd 100644
--- a/sys/compat/linuxkpi/common/include/linux/interrupt.h
+++ b/sys/compat/linuxkpi/common/include/linux/interrupt.h
@@ -55,9 +55,11 @@ struct irq_ent {
 static inline int
 linux_irq_rid(struct device *dev, unsigned int irq)
 {
-	if (irq == dev->irq)
+	/* check for MSI- or MSIX- interrupt */
+	if (irq >= dev->irq_start && irq < dev->irq_end)
+		return (irq - dev->irq_start + 1);
+	else
 		return (0);
-	return irq - dev->msix + 1;
 }
 
 extern void linux_irq_handler(void *);
diff --git a/sys/compat/linuxkpi/common/include/linux/pci.h b/sys/compat/linuxkpi/common/include/linux/pci.h
index a938b730e97..82f1124efbc 100644
--- a/sys/compat/linuxkpi/common/include/linux/pci.h
+++ b/sys/compat/linuxkpi/common/include/linux/pci.h
@@ -228,6 +228,7 @@ struct pci_dev {
 	unsigned int		devfn;
 	uint32_t		class;
 	uint8_t			revision;
+	bool			msi_enabled;
 };
 
 static inline struct resource_list_entry *
@@ -262,7 +263,7 @@ linux_pci_find_irq_dev(unsigned int irq)
 	spin_lock(&pci_lock);
 	list_for_each_entry(pdev, &pci_devices, links) {
 		if (irq == pdev->dev.irq ||
-		    (irq >= pdev->dev.msix && irq < pdev->dev.msix_max)) {
+		    (irq >= pdev->dev.irq_start && irq < pdev->dev.irq_end)) {
 			found = &pdev->dev;
 			break;
 		}
@@ -424,8 +425,23 @@ pci_disable_msix(struct pci_dev *pdev)
 	 * linux_pci_find_irq_dev() does no longer see them by
 	 * resetting their references to zero:
 	 */
-	pdev->dev.msix = 0;
-	pdev->dev.msix_max = 0;
+	pdev->dev.irq_start = 0;
+	pdev->dev.irq_end = 0;
+}
+
+#define	pci_disable_msi(pdev) \
+  linux_pci_disable_msi(pdev)
+
+static inline void
+linux_pci_disable_msi(struct pci_dev *pdev)
+{
+
+	pci_release_msi(pdev->dev.bsddev);
+
+	pdev->dev.irq_start = 0;
+	pdev->dev.irq_end = 0;
+	pdev->irq = pdev->dev.irq;
+	pdev->msi_enabled = false;
 }
 
 unsigned long	pci_resource_start(struct pci_dev *pdev, int bar);
@@ -562,10 +578,10 @@ pci_enable_msix(struct pci_dev *pdev, struct msix_entry *entries, int nreq)
 		return avail;
 	}
 	rle = linux_pci_get_rle(pdev, SYS_RES_IRQ, 1);
-	pdev->dev.msix = rle->start;
-	pdev->dev.msix_max = rle->start + avail;
+	pdev->dev.irq_start = rle->start;
+	pdev->dev.irq_end = rle->start + avail;
 	for (i = 0; i < nreq; i++)
-		entries[i].vector = pdev->dev.msix + i;
+		entries[i].vector = pdev->dev.irq_start + i;
 	return (0);
 }
 
@@ -595,6 +611,32 @@ pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,
 	return (nvec);
 }
 
+#define	pci_enable_msi(pdev) \
+  linux_pci_enable_msi(pdev)
+
+static inline int
+pci_enable_msi(struct pci_dev *pdev)
+{
+	struct resource_list_entry *rle;
+	int error;
+	int avail;
+
+	avail = pci_msi_count(pdev->dev.bsddev);
+	if (avail < 1)
+		return -EINVAL;
+
+	avail = 1;	/* this function only enable one MSI IRQ */
+	if ((error = -pci_alloc_msi(pdev->dev.bsddev, &avail)) != 0)
+		return error;
+
+	rle = linux_pci_get_rle(pdev, SYS_RES_IRQ, 1);
+	pdev->dev.irq_start = rle->start;
+	pdev->dev.irq_end = rle->start + avail;
+	pdev->irq = rle->start;
+	pdev->msi_enabled = true;
+	return (0);
+}
+
 static inline int
 pci_channel_offline(struct pci_dev *pdev)
 {
-- 
2.42.0