[S390] dasd: add High Performance FICON support

To support High Performance FICON, the DASD device driver has to
translate I/O requests into the new transport mode control words (TCW)
instead of the traditional (command mode) CCW requests.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index 34339902efb9..da231a787cee 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -67,6 +67,8 @@ int dasd_probeonly =  0;	/* is true, when probeonly mode is active */
 int dasd_autodetect = 0;        /* is true, when autodetection is active */
 int dasd_nopav = 0;             /* is true, when PAV is disabled */
 EXPORT_SYMBOL_GPL(dasd_nopav);
+int dasd_nofcx;                 /* disable High Performance Ficon */
+EXPORT_SYMBOL_GPL(dasd_nofcx);
 
 /*
  * char *dasd[] is intended to hold the ranges supplied by the dasd= statement
@@ -272,6 +274,11 @@ dasd_parse_keyword( char *parsestring ) {
                 }
                 return residual_str;
         }
+        if (strncmp("nofcx", parsestring, length) == 0) {
+                dasd_nofcx = 1;
+                MESSAGE(KERN_INFO, "%s", "disable High Performance Ficon");
+                return residual_str;
+        }
         if (strncmp("fixedbuffers", parsestring, length) == 0) {
                 if (dasd_page_cache)
                         return residual_str;