s390/pci: define kernel parameters for PCI multifunction

Using PCI multifunctions in S390 is a new feature we may want
to ignore to continue provide the same topology as in the past
to userland even if the configuration supports exposing the
topology of a multi-Function device.

A new boolean parameters allows to overwrite the kernel
pci configuration:

- pci=norid when on, disallow the use a new firmware field,
  RID, which provides the PCI <bus>:<device>.<function> part
  of the PCI address.

To be used in the following patches and satisfy the checkpatch.pl
the variable is exposed in pci.h

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 94ca121933de..3386a46f6bde 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -48,6 +48,8 @@ static unsigned int zpci_num_domains_allocated;
 	min(((unsigned long) ZPCI_NR_DEVICES * PCI_STD_NUM_BARS / 2),	\
 	    ZPCI_IOMAP_MAX_ENTRIES)
 
+unsigned int s390_pci_no_rid;
+
 static DEFINE_SPINLOCK(zpci_iomap_lock);
 static unsigned long *zpci_iomap_bitmap;
 struct zpci_iomap_entry *zpci_iomap_start;
@@ -844,6 +846,10 @@ char * __init pcibios_setup(char *str)
 		s390_pci_force_floating = 1;
 		return NULL;
 	}
+	if (!strcmp(str, "norid")) {
+		s390_pci_no_rid = 1;
+		return NULL;
+	}
 	return str;
 }