drm/amdgpu: Convert to Linux IRQ interfaces

Drop the DRM IRQ midlayer in favor of Linux IRQ interfaces. DRM's
IRQ helpers are mostly useful for UMS drivers. Modern KMS drivers
don't benefit from using it.

DRM IRQ callbacks are now being called directly or inlined.

The interrupt number returned by pci_msi_vector() is now stored
in struct amdgpu_irq. Calls to pci_msi_vector() can fail and return
a negative errno code. Abort initlaizaton in thi case. The DRM IRQ
midlayer does not handle this correctly.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210803090704.32152-2-tzimmermann@suse.de

drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

@@ -1777,7 +1777,6 @@ static const struct drm_driver amdgpu_kms_driver = {
 	.open = amdgpu_driver_open_kms,
 	.postclose = amdgpu_driver_postclose_kms,
 	.lastclose = amdgpu_driver_lastclose_kms,
-	.irq_handler = amdgpu_irq_handler,
 	.ioctls = amdgpu_ioctls_kms,
 	.num_ioctls = ARRAY_SIZE(amdgpu_ioctls_kms),
 	.dumb_create = amdgpu_mode_dumb_create,

drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c

@@ -46,7 +46,6 @@
 #include <linux/pci.h>
 
 #include <drm/drm_crtc_helper.h>
-#include <drm/drm_irq.h>
 #include <drm/drm_vblank.h>
 #include <drm/amdgpu_drm.h>
 #include <drm/drm_drv.h>
@@ -184,7 +183,7 @@ void amdgpu_irq_disable_all(struct amdgpu_device *adev)
  * Returns:
  * result of handling the IRQ, as defined by &irqreturn_t
  */
-irqreturn_t amdgpu_irq_handler(int irq, void *arg)
+static irqreturn_t amdgpu_irq_handler(int irq, void *arg)
 {
 	struct drm_device *dev = (struct drm_device *) arg;
 	struct amdgpu_device *adev = drm_to_adev(dev);
@@ -307,6 +306,7 @@ static void amdgpu_restore_msix(struct amdgpu_device *adev)
 int amdgpu_irq_init(struct amdgpu_device *adev)
 {
 	int r = 0;
+	unsigned int irq;
 
 	spin_lock_init(&adev->irq.lock);
 
@@ -349,15 +349,22 @@ int amdgpu_irq_init(struct amdgpu_device *adev)
 	INIT_WORK(&adev->irq.ih2_work, amdgpu_irq_handle_ih2);
 	INIT_WORK(&adev->irq.ih_soft_work, amdgpu_irq_handle_ih_soft);
 
-	adev->irq.installed = true;
-	/* Use vector 0 for MSI-X */
-	r = drm_irq_install(adev_to_drm(adev), pci_irq_vector(adev->pdev, 0));
+	/* Use vector 0 for MSI-X. */
+	r = pci_irq_vector(adev->pdev, 0);
+	if (r < 0)
+		return r;
+	irq = r;
+
+	/* PCI devices require shared interrupts. */
+	r = request_irq(irq, amdgpu_irq_handler, IRQF_SHARED, adev_to_drm(adev)->driver->name,
+			adev_to_drm(adev));
 	if (r) {
-		adev->irq.installed = false;
 		if (!amdgpu_device_has_dc_support(adev))
 			flush_work(&adev->hotplug_work);
 		return r;
 	}
+	adev->irq.installed = true;
+	adev->irq.irq = irq;
 	adev_to_drm(adev)->max_vblank_count = 0x00ffffff;
 
 	DRM_DEBUG("amdgpu: irq initialized.\n");
@@ -368,7 +375,7 @@ int amdgpu_irq_init(struct amdgpu_device *adev)
 void amdgpu_irq_fini_hw(struct amdgpu_device *adev)
 {
 	if (adev->irq.installed) {
-		drm_irq_uninstall(&adev->ddev);
+		free_irq(adev->irq.irq, adev_to_drm(adev));
 		adev->irq.installed = false;
 		if (adev->irq.msi_enabled)
 			pci_free_irq_vectors(adev->pdev);

drivers/gpu/drm/amd/amdgpu/amdgpu_irq.h

@@ -80,6 +80,7 @@ struct amdgpu_irq_src_funcs {
 
 struct amdgpu_irq {
 	bool				installed;
+	unsigned int			irq;
 	spinlock_t			lock;
 	/* interrupt sources */
 	struct amdgpu_irq_client	client[AMDGPU_IRQ_CLIENTID_MAX];
@@ -100,7 +101,6 @@ struct amdgpu_irq {
 };
 
 void amdgpu_irq_disable_all(struct amdgpu_device *adev);
-irqreturn_t amdgpu_irq_handler(int irq, void *arg);
 
 int amdgpu_irq_init(struct amdgpu_device *adev);
 void amdgpu_irq_fini_sw(struct amdgpu_device *adev);