[S390] cio: Cleanup crw interface.

Eliminate the need for the machine check handler to call into
the common I/O layer directly by introducing an interface to
register handlers for crws per rsc.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

1 files changed, 46 insertions, 56 deletions

diff --git a/drivers/s390/s390mach.c b/drivers/s390/s390mach.c
index 5bfbe7659830..fe75152a5084 100644
--- a/drivers/s390/s390mach.c
+++ b/drivers/s390/s390mach.c
@@ -2,10 +2,10 @@
  *  drivers/s390/s390mach.c
  *   S/390 machine check handler
  *
- *  S390 version
- *    Copyright (C) 2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *    Copyright IBM Corp. 2000,2008
  *    Author(s): Ingo Adlung (adlung@de.ibm.com)
  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
+ *               Cornelia Huck <cornelia.huck@de.ibm.com>
  */
 
 #include <linux/init.h>
@@ -18,10 +18,6 @@
 #include <asm/etr.h>
 #include <asm/lowcore.h>
 #include <asm/cio.h>
-#include "cio/cio.h"
-#include "cio/chsc.h"
-#include "cio/css.h"
-#include "cio/chp.h"
 #include "s390mach.h"
 
 static struct semaphore m_sem;
@@ -36,13 +32,40 @@ s390_handle_damage(char *msg)
         for(;;);
 }
 
+static crw_handler_t crw_handlers[NR_RSCS];
+
+/**
+ * s390_register_crw_handler() - register a channel report word handler
+ * @rsc: reporting source code to handle
+ * @handler: handler to be registered
+ *
+ * Returns %0 on success and a negative error value otherwise.
+ */
+int s390_register_crw_handler(int rsc, crw_handler_t handler)
+{
+        if ((rsc < 0) || (rsc >= NR_RSCS))
+                return -EINVAL;
+        if (!cmpxchg(&crw_handlers[rsc], NULL, handler))
+                return 0;
+        return -EBUSY;
+}
+
+/**
+ * s390_unregister_crw_handler() - unregister a channel report word handler
+ * @rsc: reporting source code to handle
+ */
+void s390_unregister_crw_handler(int rsc)
+{
+        if ((rsc < 0) || (rsc >= NR_RSCS))
+                return;
+        xchg(&crw_handlers[rsc], NULL);
+        synchronize_sched();
+}
+
 /*
  * Retrieve CRWs and call function to handle event.
- *
- * Note : we currently process CRWs for io and chsc subchannels only
  */
-static int
-s390_collect_crw_info(void *param)
+static int s390_collect_crw_info(void *param)
 {
         struct crw crw[2];
         int ccode;
@@ -84,57 +107,24 @@ repeat:
                        crw[chain].rsid);
                 /* Check for overflows. */
                 if (crw[chain].oflw) {
+                        int i;
+
                         pr_debug("%s: crw overflow detected!\n", __func__);
-                        css_schedule_eval_all();
+                        for (i = 0; i < NR_RSCS; i++) {
+                                if (crw_handlers[i])
+                                        crw_handlers[i](NULL, NULL, 1);
+                        }
                         chain = 0;
                         continue;
                 }
-                switch (crw[chain].rsc) {
-                case CRW_RSC_SCH:
-                        if (crw[0].chn && !chain)
-                                break;
-                        pr_debug("source is subchannel %04X\n", crw[0].rsid);
-                        css_process_crw(crw[0].rsid, chain ? crw[1].rsid : 0);
-                        break;
-                case CRW_RSC_MONITOR:
-                        pr_debug("source is monitoring facility\n");
-                        break;
-                case CRW_RSC_CPATH:
-                        pr_debug("source is channel path %02X\n", crw[0].rsid);
-                        /*
-                         * Check for solicited machine checks. These are
-                         * created by reset channel path and need not be
-                         * reported to the common I/O layer.
-                         */
-                        if (crw[chain].slct) {
-                                pr_debug("solicited machine check for "
-                                         "channel path %02X\n", crw[0].rsid);
-                                break;
-                        }
-                        switch (crw[0].erc) {
-                        case CRW_ERC_IPARM: /* Path has come. */
-                                chp_process_crw(crw[0].rsid, 1);
-                                break;
-                        case CRW_ERC_PERRI: /* Path has gone. */
-                        case CRW_ERC_PERRN:
-                                chp_process_crw(crw[0].rsid, 0);
-                                break;
-                        default:
-                                pr_debug("Don't know how to handle erc=%x\n",
-                                         crw[0].erc);
-                        }
-                        break;
-                case CRW_RSC_CONFIG:
-                        pr_debug("source is configuration-alert facility\n");
-                        break;
-                case CRW_RSC_CSS:
-                        pr_debug("source is channel subsystem\n");
-                        chsc_process_crw();
-                        break;
-                default:
-                        pr_debug("unknown source\n");
-                        break;
+                if (crw[0].chn && !chain) {
+                        chain++;
+                        continue;
                 }
+                if (crw_handlers[crw[chain].rsc])
+                        crw_handlers[crw[chain].rsc](&crw[0],
+                                                     chain ? &crw[1] : NULL,
+                                                     0);
                 /* chain is always 0 or 1 here. */
                 chain = crw[chain].chn ? chain + 1 : 0;
         }