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 s390_readinfo_sccb;
  15
  16 void __init sclp_readinfo_early(void)
  17 {
  18         sclp_cmdw_t command;
  19         struct sccb_header *sccb;
  20         int ret;
  21
  22         __ctl_set_bit(0, 9); /* enable service signal subclass mask */
  23
  24         sccb = &s390_readinfo_sccb.header;
  25         command = SCLP_CMDW_READ_SCP_INFO_FORCED;
  26         while (1) {
  27                 u16 response;
  28
  29                 memset(&s390_readinfo_sccb, 0, sizeof(s390_readinfo_sccb));
  30                 sccb->length = sizeof(s390_readinfo_sccb);
  31                 sccb->control_mask[2] = 0x80;
  32
  33                 ret = sclp_service_call(command, &s390_readinfo_sccb);
  34
  35                 if (ret == -EIO)
  36                         goto out;
  37                 if (ret == -EBUSY)
  38                         continue;
  39
  40                 __load_psw_mask(PSW_BASE_BITS | PSW_MASK_EXT |
  41                                 PSW_MASK_WAIT | PSW_DEFAULT_KEY);
  42                 local_irq_disable();
  43                 barrier();
  44
  45                 response = sccb->response_code;
  46
  47                 if (response == 0x10)
  48                         break;
  49
  50                 if (response != 0x1f0 || command == SCLP_CMDW_READ_SCP_INFO)
  51                         break;
  52
  53                 command = SCLP_CMDW_READ_SCP_INFO;
  54         }
  55 out:
  56         __ctl_clear_bit(0, 9); /* disable service signal subclass mask */
  57 }