drivers/s390/char/sclp_info.c

   1 /*
   2  *  drivers/s390/char/sclp_info.c
   3  *
   4  *    Copyright IBM Corp. 2007
   5  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   6  */
   7
   8 #include <linux/init.h>
   9 #include <linux/errno.h>
  10 #include <linux/string.h>
  11 #include <asm/sclp.h>
  12 #include "sclp.h"
  13
  14 struct sclp_readinfo_sccb {
  15         struct  sccb_header header;     /* 0-7 */
  16         u16     rnmax;                  /* 8-9 */
  17         u8      rnsize;                 /* 10 */
  18         u8      _reserved0[24 - 11];    /* 11-23 */
  19         u8      loadparm[8];            /* 24-31 */
  20         u8      _reserved1[48 - 32];    /* 32-47 */
  21         u64     facilities;             /* 48-55 */
  22         u8      _reserved2[91 - 56];    /* 56-90 */
  23         u8      flags;                  /* 91 */
  24         u8      _reserved3[100 - 92];   /* 92-99 */
  25         u32     rnsize2;                /* 100-103 */
  26         u64     rnmax2;                 /* 104-111 */
  27         u8      _reserved4[4096 - 112]; /* 112-4095 */
  28 } __attribute__((packed, aligned(4096)));
  29
  30 static struct sclp_readinfo_sccb __initdata early_readinfo_sccb;
  31 static int __initdata early_readinfo_sccb_valid;
  32
  33 u64 sclp_facilities;
  34
  35 void __init sclp_readinfo_early(void)
  36 {
  37         int ret;
  38         int i;
  39         struct sclp_readinfo_sccb *sccb;
  40         sclp_cmdw_t commands[] = {SCLP_CMDW_READ_SCP_INFO_FORCED,
  41                                   SCLP_CMDW_READ_SCP_INFO};
  42
  43         /* Enable service signal subclass mask. */
  44         __ctl_set_bit(0, 9);
  45         sccb = &early_readinfo_sccb;
  46         for (i = 0; i < ARRAY_SIZE(commands); i++) {
  47                 do {
  48                         memset(sccb, 0, sizeof(*sccb));
  49                         sccb->header.length = sizeof(*sccb);
  50                         sccb->header.control_mask[2] = 0x80;
  51                         ret = sclp_service_call(commands[i], sccb);
  52                 } while (ret == -EBUSY);
  53
  54                 if (ret)
  55                         break;
  56                 __load_psw_mask(PSW_BASE_BITS | PSW_MASK_EXT |
  57                                 PSW_MASK_WAIT | PSW_DEFAULT_KEY);
  58                 local_irq_disable();
  59                 /*
  60                  * Contents of the sccb might have changed
  61                  * therefore a barrier is needed.
  62                  */
  63                 barrier();
  64                 if (sccb->header.response_code == 0x10) {
  65                         early_readinfo_sccb_valid = 1;
  66                         break;
  67                 }
  68                 if (sccb->header.response_code != 0x1f0)
  69                         break;
  70         }
  71         /* Disable service signal subclass mask again. */
  72         __ctl_clear_bit(0, 9);
  73 }
  74
  75 void __init sclp_facilities_detect(void)
  76 {
  77         if (!early_readinfo_sccb_valid)
  78                 return;
  79         sclp_facilities = early_readinfo_sccb.facilities;
  80 }
  81
  82 unsigned long long __init sclp_memory_detect(void)
  83 {
  84         unsigned long long memsize;
  85         struct sclp_readinfo_sccb *sccb;
  86
  87         if (!early_readinfo_sccb_valid)
  88                 return 0;
  89         sccb = &early_readinfo_sccb;
  90         if (sccb->rnsize)
  91                 memsize = sccb->rnsize << 20;
  92         else
  93                 memsize = sccb->rnsize2 << 20;
  94         if (sccb->rnmax)
  95                 memsize *= sccb->rnmax;
  96         else
  97                 memsize *= sccb->rnmax2;
  98         return memsize;
  99 }
 100
 101 /*
 102  * This function will be called after sclp_memory_detect(), which gets called
 103  * early from early.c code. Therefore the sccb should have valid contents.
 104  */
 105 void __init sclp_get_ipl_info(struct sclp_ipl_info *info)
 106 {
 107         struct sclp_readinfo_sccb *sccb;
 108
 109         if (!early_readinfo_sccb_valid)
 110                 return;
 111         sccb = &early_readinfo_sccb;
 112         info->is_valid = 1;
 113         if (sccb->flags & 0x2)
 114                 info->has_dump = 1;
 115         memcpy(&info->loadparm, &sccb->loadparm, LOADPARM_LEN);
 116 }