[S390] sclp: introduce some new interfaces.

Introduce some new interfaces so that random subsystems don't have to
mess around with sclp internal structures.

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

2 files changed, 86 insertions, 29 deletions

diff --git a/drivers/s390/char/sclp.h b/drivers/s390/char/sclp.h
index dbb99d1b6f57..cb5888f79007 100644
--- a/drivers/s390/char/sclp.h
+++ b/drivers/s390/char/sclp.h
@@ -72,6 +72,13 @@ typedef unsigned int sclp_cmdw_t;
 
 typedef u32 sccb_mask_t;        /* ATTENTION: assumes 32bit mask !!! */
 
+struct sccb_header {
+        u16     length;
+        u8      function_code;
+        u8      control_mask[3];
+        u16     response_code;
+} __attribute__((packed));
+
 struct gds_subvector {
         u8      length;
         u8      key;
diff --git a/drivers/s390/char/sclp_info.c b/drivers/s390/char/sclp_info.c
index 7bcbe643b087..7d21dbb12fcd 100644
--- a/drivers/s390/char/sclp_info.c
+++ b/drivers/s390/char/sclp_info.c
@@ -11,47 +11,97 @@
 #include <asm/sclp.h>
 #include "sclp.h"
 
-struct sclp_readinfo_sccb s390_readinfo_sccb;
+struct sclp_readinfo_sccb {
+        struct  sccb_header header;     /* 0-7 */
+        u16     rnmax;                  /* 8-9 */
+        u8      rnsize;                 /* 10 */
+        u8      _reserved0[24 - 11];    /* 11-23 */
+        u8      loadparm[8];            /* 24-31 */
+        u8      _reserved1[48 - 32];    /* 32-47 */
+        u64     facilities;             /* 48-55 */
+        u8      _reserved2[91 - 56];    /* 56-90 */
+        u8      flags;                  /* 91 */
+        u8      _reserved3[100 - 92];   /* 92-99 */
+        u32     rnsize2;                /* 100-103 */
+        u64     rnmax2;                 /* 104-111 */
+        u8      _reserved4[4096 - 112]; /* 112-4095 */
+} __attribute__((packed, aligned(4096)));
+
+static struct sclp_readinfo_sccb __initdata early_readinfo_sccb;
+static int __initdata early_readinfo_sccb_valid;
 
 void __init sclp_readinfo_early(void)
 {
-        sclp_cmdw_t command;
-        struct sccb_header *sccb;
         int ret;
+        int i;
+        struct sclp_readinfo_sccb *sccb;
+        sclp_cmdw_t commands[] = {SCLP_CMDW_READ_SCP_INFO_FORCED,
+                                  SCLP_CMDW_READ_SCP_INFO};
 
-        __ctl_set_bit(0, 9); /* enable service signal subclass mask */
-
-        sccb = &s390_readinfo_sccb.header;
-        command = SCLP_CMDW_READ_SCP_INFO_FORCED;
-        while (1) {
-                u16 response;
-
-                memset(&s390_readinfo_sccb, 0, sizeof(s390_readinfo_sccb));
-                sccb->length = sizeof(s390_readinfo_sccb);
-                sccb->control_mask[2] = 0x80;
-
-                ret = sclp_service_call(command, &s390_readinfo_sccb);
-
-                if (ret == -EIO)
-                        goto out;
-                if (ret == -EBUSY)
-                        continue;
+        /* Enable service signal subclass mask. */
+        __ctl_set_bit(0, 9);
+        sccb = &early_readinfo_sccb;
+        for (i = 0; i < ARRAY_SIZE(commands); i++) {
+                do {
+                        memset(sccb, 0, sizeof(*sccb));
+                        sccb->header.length = sizeof(*sccb);
+                        sccb->header.control_mask[2] = 0x80;
+                        ret = sclp_service_call(commands[i], sccb);
+                } while (ret == -EBUSY);
 
+                if (ret)
+                        break;
                 __load_psw_mask(PSW_BASE_BITS | PSW_MASK_EXT |
                                 PSW_MASK_WAIT | PSW_DEFAULT_KEY);
                 local_irq_disable();
+                /*
+                 * Contents of the sccb might have changed
+                 * therefore a barrier is needed.
+                 */
                 barrier();
+                if (sccb->header.response_code == 0x10) {
+                        early_readinfo_sccb_valid = 1;
+                        break;
+                }
+                if (sccb->header.response_code != 0x1f0)
+                        break;
+        }
+        /* Disable service signal subclass mask again. */
+        __ctl_clear_bit(0, 9);
+}
 
-                response = sccb->response_code;
+unsigned long long __init sclp_memory_detect(void)
+{
+        unsigned long long memsize;
+        struct sclp_readinfo_sccb *sccb;
 
-                if (response == 0x10)
-                        break;
+        if (!early_readinfo_sccb_valid)
+                return 0;
+        sccb = &early_readinfo_sccb;
+        if (sccb->rnsize)
+                memsize = sccb->rnsize << 20;
+        else
+                memsize = sccb->rnsize2 << 20;
+        if (sccb->rnmax)
+                memsize *= sccb->rnmax;
+        else
+                memsize *= sccb->rnmax2;
+        return memsize;
+}
 
-                if (response != 0x1f0 || command == SCLP_CMDW_READ_SCP_INFO)
-                        break;
+/*
+ * This function will be called after sclp_memory_detect(), which gets called
+ * early from early.c code. Therefore the sccb should have valid contents.
+ */
+void __init sclp_get_ipl_info(struct sclp_ipl_info *info)
+{
+        struct sclp_readinfo_sccb *sccb;
 
-                command = SCLP_CMDW_READ_SCP_INFO;
-        }
-out:
-        __ctl_clear_bit(0, 9); /* disable service signal subclass mask */
+        if (!early_readinfo_sccb_valid)
+                return;
+        sccb = &early_readinfo_sccb;
+        info->is_valid = 1;
+        if (sccb->flags & 0x2)
+                info->has_dump = 1;
+        memcpy(&info->loadparm, &sccb->loadparm, LOADPARM_LEN);
 }