iommu/amd: Clean up bus_set_iommu()

Stop calling bus_set_iommu() since it's now unnecessary, and
garbage-collect the last remnants of amd_iommu_init_api().
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/6bcc367e8802ae5a2b2840cbe4e9661ee024e80e.1660572783.git.robin.murphy@arm.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

drivers/iommu/amd/amd_iommu.h

@@ -18,7 +18,6 @@ extern void amd_iommu_restart_event_logging(struct amd_iommu *iommu);
 extern int amd_iommu_init_devices(void);
 extern void amd_iommu_uninit_devices(void);
 extern void amd_iommu_init_notifier(void);
-extern int amd_iommu_init_api(void);
 extern void amd_iommu_set_rlookup_table(struct amd_iommu *iommu, u16 devid);
 
 #ifdef CONFIG_AMD_IOMMU_DEBUGFS

drivers/iommu/amd/init.c

@@ -2168,20 +2168,13 @@ static int __init amd_iommu_init_pci(void)
 	/*
 	 * Order is important here to make sure any unity map requirements are
 	 * fulfilled. The unity mappings are created and written to the device
-	 * table during the amd_iommu_init_api() call.
+	 * table during the iommu_init_pci() call.
 	 *
 	 * After that we call init_device_table_dma() to make sure any
 	 * uninitialized DTE will block DMA, and in the end we flush the caches
 	 * of all IOMMUs to make sure the changes to the device table are
 	 * active.
 	 */
-	ret = amd_iommu_init_api();
-	if (ret) {
-		pr_err("IOMMU: Failed to initialize IOMMU-API interface (error=%d)!\n",
-		       ret);
-		goto out;
-	}
-
 	for_each_pci_segment(pci_seg)
 		init_device_table_dma(pci_seg);
 

drivers/iommu/amd/iommu.c

@@ -11,8 +11,6 @@
 #include <linux/ratelimit.h>
 #include <linux/pci.h>
 #include <linux/acpi.h>
-#include <linux/amba/bus.h>
-#include <linux/platform_device.h>
 #include <linux/pci-ats.h>
 #include <linux/bitmap.h>
 #include <linux/slab.h>
@@ -1941,25 +1939,6 @@ void amd_iommu_domain_update(struct protection_domain *domain)
 	amd_iommu_domain_flush_complete(domain);
 }
 
-int __init amd_iommu_init_api(void)
-{
-	int err;
-
-	err = bus_set_iommu(&pci_bus_type, &amd_iommu_ops);
-	if (err)
-		return err;
-#ifdef CONFIG_ARM_AMBA
-	err = bus_set_iommu(&amba_bustype, &amd_iommu_ops);
-	if (err)
-		return err;
-#endif
-	err = bus_set_iommu(&platform_bus_type, &amd_iommu_ops);
-	if (err)
-		return err;
-
-	return 0;
-}
-
 /*****************************************************************************
  *
  * The following functions belong to the exported interface of AMD IOMMU