Revert "cxl: Add cxl_slot_is_supported API"

Remove abandonned capi support for the Mellanox CX4.

This reverts commit 4e56f858bd.

Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

drivers/misc/cxl/pci.c

@@ -1808,43 +1808,6 @@ int cxl_slot_is_switched(struct pci_dev *dev)
 	return (depth > CXL_MAX_PCIEX_PARENT);
 }
 
-bool cxl_slot_is_supported(struct pci_dev *dev, int flags)
-{
-	if (!cpu_has_feature(CPU_FTR_HVMODE))
-		return false;
-
-	if ((flags & CXL_SLOT_FLAG_DMA) && (!pvr_version_is(PVR_POWER8NVL))) {
-		/*
-		 * CAPP DMA mode is technically supported on regular P8, but
-		 * will EEH if the card attempts to access memory < 4GB, which
-		 * we cannot realistically avoid. We might be able to work
-		 * around the issue, but until then return unsupported:
-		 */
-		return false;
-	}
-
-	if (cxl_slot_is_switched(dev))
-		return false;
-
-	/*
-	 * XXX: This gets a little tricky on regular P8 (not POWER8NVL) since
-	 * the CAPP can be connected to PHB 0, 1 or 2 on a first come first
-	 * served basis, which is racy to check from here. If we need to
-	 * support this in future we might need to consider having this
-	 * function effectively reserve it ahead of time.
-	 *
-	 * Currently, the only user of this API is the Mellanox CX4, which is
-	 * only supported on P8NVL due to the above mentioned limitation of
-	 * CAPP DMA mode and therefore does not need to worry about this. If the
-	 * issue with CAPP DMA mode is later worked around on P8 we might need
-	 * to revisit this.
-	 */
-
-	return true;
-}
-EXPORT_SYMBOL_GPL(cxl_slot_is_supported);
-
-
 static int cxl_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {
 	struct cxl *adapter;

include/misc/cxl.h

@@ -24,21 +24,6 @@
  * generic PCI API. This API is agnostic to the actual AFU.
  */
 
-#define CXL_SLOT_FLAG_DMA 0x1
-
-/*
- * Checks if the given card is in a cxl capable slot. Pass CXL_SLOT_FLAG_DMA if
- * the card requires CAPP DMA mode to also check if the system supports it.
- * This is intended to be used by bi-modal devices to determine if they can use
- * cxl mode or if they should continue running in PCI mode.
- *
- * Note that this only checks if the slot is cxl capable - it does not
- * currently check if the CAPP is currently available for chips where it can be
- * assigned to different PHBs on a first come first serve basis (i.e. P8)
- */
-bool cxl_slot_is_supported(struct pci_dev *dev, int flags);
-
-
 /* Get the AFU associated with a pci_dev */
 struct cxl_afu *cxl_pci_to_afu(struct pci_dev *dev);