cxlflash: Simplify PCI registration

The calls to pci_request_regions(), pci_resource_start(),
pci_set_dma_mask(), pci_set_master() and pci_save_state() are all
unnecessary for the IBM CXL flash adapter since data buffers
are not required to be mapped to the device's memory.

The use of services such as pci_set_dma_mask() are problematic on
hypervisor managed systems as the IBM CXL flash adapter is operating
under a virtual PCI Host Bridge (virtual PHB) which does not support
these services.

cxlflash 0001:00:00.0: init_pci: Failed to set PCI DMA mask rc=-5

The resolution is to simplify init_pci(), to a point where it does the
bare minimum (pci_enable_device). Similarly, remove the call the
pci_release_regions() from cxlflash_remove().
Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Reviewed-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/cxlflash/main.c

@@ -767,7 +767,6 @@ static void cxlflash_remove(struct pci_dev *pdev)
 		cancel_work_sync(&cfg->work_q);
 		term_afu(cfg);
 	case INIT_STATE_PCI:
-		pci_release_regions(cfg->dev);
 		pci_disable_device(pdev);
 	case INIT_STATE_NONE:
 		free_mem(cfg);
@@ -840,15 +839,6 @@ static int init_pci(struct cxlflash_cfg *cfg)
 	struct pci_dev *pdev = cfg->dev;
 	int rc = 0;
 
-	cfg->cxlflash_regs_pci = pci_resource_start(pdev, 0);
-	rc = pci_request_regions(pdev, CXLFLASH_NAME);
-	if (rc < 0) {
-		dev_err(&pdev->dev,
-			"%s: Couldn't register memory range of registers\n",
-			__func__);
-		goto out;
-	}
-
 	rc = pci_enable_device(pdev);
 	if (rc || pci_channel_offline(pdev)) {
 		if (pci_channel_offline(pdev)) {
@@ -860,55 +850,13 @@ static int init_pci(struct cxlflash_cfg *cfg)
 			dev_err(&pdev->dev, "%s: Cannot enable adapter\n",
 				__func__);
 			cxlflash_wait_for_pci_err_recovery(cfg);
-			goto out_release_regions;
-		}
-	}
-
-	rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(64));
-	if (rc < 0) {
-		dev_dbg(&pdev->dev, "%s: Failed to set 64 bit PCI DMA mask\n",
-			__func__);
-		rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
-	}
-
-	if (rc < 0) {
-		dev_err(&pdev->dev, "%s: Failed to set PCI DMA mask\n",
-			__func__);
-		goto out_disable;
-	}
-
-	pci_set_master(pdev);
-
-	if (pci_channel_offline(pdev)) {
-		cxlflash_wait_for_pci_err_recovery(cfg);
-		if (pci_channel_offline(pdev)) {
-			rc = -EIO;
-			goto out_msi_disable;
+			goto out;
 		}
 	}
 
-	rc = pci_save_state(pdev);
-
-	if (rc != PCIBIOS_SUCCESSFUL) {
-		dev_err(&pdev->dev, "%s: Failed to save PCI config space\n",
-			__func__);
-		rc = -EIO;
-		goto cleanup_nolog;
-	}
-
 out:
 	pr_debug("%s: returning rc=%d\n", __func__, rc);
 	return rc;
-
-cleanup_nolog:
-out_msi_disable:
-	cxlflash_wait_for_pci_err_recovery(cfg);
-out_disable:
-	pci_disable_device(pdev);
-out_release_regions:
-	pci_release_regions(pdev);
-	goto out;
-
 }
 
 /**