hsa/radeon: Workaround for a bug in amd_iommu

This patch creates a workaround for a bug in amd_iommu driver, where the driver
doesn't save all necessary information when going to suspend.
The workaround removes a device from the IOMMU device list on suspend and register a resumed device in the IOMMU device list.

Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>

drivers/gpu/hsa/radeon/Makefile

@@ -5,6 +5,6 @@
 radeon_kfd-y	:= kfd_module.o kfd_device.o kfd_chardev.o \
 		kfd_pasid.o kfd_topology.o kfd_process.o \
 		kfd_doorbell.o kfd_sched_cik_static.o kfd_registers.o \
-		kfd_vidmem.o kfd_interrupt.o kfd_pm.o
+		kfd_vidmem.o kfd_interrupt.o
 
 obj-$(CONFIG_HSA_RADEON)	+= radeon_kfd.o

drivers/gpu/hsa/radeon/kfd_device.c

@@ -188,3 +188,32 @@ void kgd2kfd_device_exit(struct kfd_dev *kfd)
 
 	kfree(kfd);
 }
+
+void kgd2kfd_suspend(struct kfd_dev *kfd)
+{
+	BUG_ON(kfd == NULL);
+
+	if (kfd->init_complete) {
+		kfd->device_info->scheduler_class->stop(kfd->scheduler);
+		amd_iommu_free_device(kfd->pdev);
+	}
+}
+
+int kgd2kfd_resume(struct kfd_dev *kfd)
+{
+	pasid_t pasid_limit;
+	int err;
+	BUG_ON(kfd == NULL);
+
+	pasid_limit = radeon_kfd_get_pasid_limit();
+
+	if (kfd->init_complete) {
+		err = amd_iommu_init_device(kfd->pdev, pasid_limit);
+		if (err < 0)
+			return -ENXIO;
+		amd_iommu_set_invalidate_ctx_cb(kfd->pdev, iommu_pasid_shutdown_callback);
+		kfd->device_info->scheduler_class->start(kfd->scheduler);
+	}
+
+	return 0;
+}

drivers/gpu/hsa/radeon/kfd_pasid.c

@@ -70,6 +70,11 @@ bool radeon_kfd_set_pasid_limit(pasid_t new_limit)
 	}
 }
 
+inline pasid_t radeon_kfd_get_pasid_limit(void)
+{
+	return pasid_limit;
+}
+
 pasid_t radeon_kfd_pasid_alloc(void)
 {
 	pasid_t found;

drivers/gpu/hsa/radeon/kfd_priv.h

@@ -205,6 +205,7 @@ struct kfd_queue *radeon_kfd_get_queue(struct kfd_process *p, unsigned int queue
 int radeon_kfd_pasid_init(void);
 void radeon_kfd_pasid_exit(void);
 bool radeon_kfd_set_pasid_limit(pasid_t new_limit);
+pasid_t radeon_kfd_get_pasid_limit(void);
 pasid_t radeon_kfd_pasid_alloc(void);
 void radeon_kfd_pasid_free(pasid_t pasid);