[S390] cio: Add chsc subchannel driver.

This patch adds a driver for subchannels of type chsc.

A device /dev/chsc is created which may be used to issue ioctls to:
- obtain information about the machine's I/O configuration
- dynamically change the machine's I/O configuration via
  asynchronous chsc commands

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, 41 insertions, 7 deletions

diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index e23c3806972a..65264a38057d 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -15,6 +15,7 @@
 
 #include <asm/cio.h>
 #include <asm/chpid.h>
+#include <asm/chsc.h>
 
 #include "../s390mach.h"
 #include "css.h"
@@ -627,23 +628,33 @@ chsc_secm(struct channel_subsystem *css, int enable)
         return ret;
 }
 
-int chsc_determine_channel_path_description(struct chp_id chpid,
-                                            struct channel_path_desc *desc)
+int chsc_determine_channel_path_desc(struct chp_id chpid, int fmt, int rfmt,
+                                     int c, int m,
+                                     struct chsc_response_struct *resp)
 {
         int ccode, ret;
 
         struct {
                 struct chsc_header request;
-                u32 : 24;
+                u32 : 2;
+                u32 m : 1;
+                u32 c : 1;
+                u32 fmt : 4;
+                u32 cssid : 8;
+                u32 : 4;
+                u32 rfmt : 4;
                 u32 first_chpid : 8;
                 u32 : 24;
                 u32 last_chpid : 8;
                 u32 zeroes1;
                 struct chsc_header response;
-                u32 zeroes2;
-                struct channel_path_desc desc;
+                u8 data[PAGE_SIZE - 20];
         } __attribute__ ((packed)) *scpd_area;
 
+        if ((rfmt == 1) && !css_general_characteristics.fcs)
+                return -EINVAL;
+        if ((rfmt == 2) && !css_general_characteristics.cib)
+                return -EINVAL;
         scpd_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
         if (!scpd_area)
                 return -ENOMEM;
@@ -651,8 +662,13 @@ int chsc_determine_channel_path_description(struct chp_id chpid,
         scpd_area->request.length = 0x0010;
         scpd_area->request.code = 0x0002;
 
+        scpd_area->cssid = chpid.cssid;
         scpd_area->first_chpid = chpid.id;
         scpd_area->last_chpid = chpid.id;
+        scpd_area->m = m;
+        scpd_area->c = c;
+        scpd_area->fmt = fmt;
+        scpd_area->rfmt = rfmt;
 
         ccode = chsc(scpd_area);
         if (ccode > 0) {
@@ -663,8 +679,7 @@ int chsc_determine_channel_path_description(struct chp_id chpid,
         ret = chsc_error_from_response(scpd_area->response.code);
         if (ret == 0)
                 /* Success. */
-                memcpy(desc, &scpd_area->desc,
-                       sizeof(struct channel_path_desc));
+                memcpy(resp, &scpd_area->response, scpd_area->response.length);
         else
                 CIO_CRW_EVENT(2, "chsc: scpd failed (rc=%04x)\n",
                               scpd_area->response.code);
@@ -672,6 +687,25 @@ out:
         free_page((unsigned long)scpd_area);
         return ret;
 }
+EXPORT_SYMBOL_GPL(chsc_determine_channel_path_desc);
+
+int chsc_determine_base_channel_path_desc(struct chp_id chpid,
+                                          struct channel_path_desc *desc)
+{
+        struct chsc_response_struct *chsc_resp;
+        int ret;
+
+        chsc_resp = kzalloc(sizeof(*chsc_resp), GFP_KERNEL);
+        if (!chsc_resp)
+                return -ENOMEM;
+        ret = chsc_determine_channel_path_desc(chpid, 0, 0, 0, 0, chsc_resp);
+        if (ret)
+                goto out_free;
+        memcpy(desc, &chsc_resp->data, chsc_resp->length);
+out_free:
+        kfree(chsc_resp);
+        return ret;
+}
 
 static void
 chsc_initialize_cmg_chars(struct channel_path *chp, u8 cmcv,