pc-bios/s390-ccw: provide a function to interpret LOADPARM value

The LOADPARM value is fetched from SCP Read Info, but it's applied
only at the phase of bootmap interpretation. So let's read the LOARPARM
value and store it. Also provide a parsing function to detect numbers in
the LOADPARM which can be used during bootmap interpretation.

Remove a stray whitespace.

Initial patch from Eugene (jno) Dvurechenski.
Signed-off-by: NEugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: NFarhan Ali <alifm@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

pc-bios/s390-ccw/main.c

@@ -14,6 +14,7 @@
 char stack[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
 static SubChannelId blk_schid = { .one = 1 };
 IplParameterBlock iplb __attribute__((__aligned__(PAGE_SIZE)));
+static char loadparm[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
 
 const unsigned char ebc2asc[256] =
       /* 0123456789abcdef0123456789abcdef */
@@ -40,7 +41,6 @@ void write_subsystem_identification(void)
     *zeroes = 0;
 }
 
-
 void panic(const char *string)
 {
     sclp_print(string);
@@ -48,6 +48,26 @@ void panic(const char *string)
     while (1) { }
 }
 
+unsigned int get_loadparm_index(void)
+{
+    const char *lp = loadparm;
+    int i;
+    unsigned int idx = 0;
+
+    for (i = 0; i < 8; i++) {
+        char c = lp[i];
+
+        if (c < '0' || c > '9') {
+            break;
+        }
+
+        idx *= 10;
+        idx += c - '0';
+    }
+
+    return idx;
+}
+
 static bool find_dev(Schib *schib, int dev_no)
 {
     int i, r;
@@ -84,6 +104,7 @@ static void virtio_setup(void)
     int ssid;
     bool found = false;
     uint16_t dev_no;
+    char ldp[] = "LOADPARM=[________]\n";
     VDev *vdev = virtio_get_device();
 
     /*
@@ -93,6 +114,10 @@ static void virtio_setup(void)
      */
     enable_mss_facility();
 
+    sclp_get_loadparm_ascii(loadparm);
+    memcpy(ldp + 10, loadparm, 8);
+    sclp_print(ldp);
+
     if (store_iplb(&iplb)) {
         switch (iplb.pbt) {
         case S390_IPL_TYPE_CCW:

pc-bios/s390-ccw/s390-ccw.h

@@ -62,6 +62,7 @@ void consume_sclp_int(void);
 void panic(const char *string);
 void write_subsystem_identification(void);
 extern char stack[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
+unsigned int get_loadparm_index(void);
 
 /* sclp.c */
 void sclp_print(const char *string);