pc-bios/s390-ccw/sclp-ascii.c

   1 /*
   2  * SCLP ASCII access driver
   3  *
   4  * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or (at
   7  * your option) any later version. See the COPYING file in the top-level
   8  * directory.
   9  */
  10
  11 #include "s390-ccw.h"
  12 #include "sclp.h"
  13
  14 static char _sccb[PAGE_SIZE] __attribute__((__aligned__(4096)));
  15
  16 /* Perform service call. Return 0 on success, non-zero otherwise. */
  17 static int sclp_service_call(unsigned int command, void *sccb)
  18 {
  19         int cc;
  20
  21         asm volatile(
  22                 "       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
  23                 "       ipm     %0\n"
  24                 "       srl     %0,28"
  25                 : "=&d" (cc) : "d" (command), "a" (__pa(sccb))
  26                 : "cc", "memory");
  27         if (cc == 3)
  28                 return -EIO;
  29         if (cc == 2)
  30                 return -EBUSY;
  31         return 0;
  32 }
  33
  34 static void sclp_set_write_mask(void)
  35 {
  36     WriteEventMask *sccb = (void*)_sccb;
  37
  38     sccb->h.length = sizeof(WriteEventMask);
  39     sccb->mask_length = sizeof(unsigned int);
  40     sccb->receive_mask = SCLP_EVENT_MASK_MSG_ASCII;
  41     sccb->cp_receive_mask = SCLP_EVENT_MASK_MSG_ASCII;
  42     sccb->send_mask = SCLP_EVENT_MASK_MSG_ASCII;
  43     sccb->cp_send_mask = SCLP_EVENT_MASK_MSG_ASCII;
  44
  45     sclp_service_call(SCLP_CMD_WRITE_EVENT_MASK, sccb);
  46 }
  47
  48 void sclp_setup(void)
  49 {
  50     sclp_set_write_mask();
  51 }
  52
  53 static int _strlen(const char *str)
  54 {
  55     int i;
  56     for (i = 0; *str; i++)
  57         str++;
  58     return i;
  59 }
  60
  61 static void _memcpy(char *dest, const char *src, int len)
  62 {
  63     int i;
  64     for (i = 0; i < len; i++)
  65         dest[i] = src[i];
  66 }
  67
  68 void sclp_print(const char *str)
  69 {
  70     int len = _strlen(str);
  71     WriteEventData *sccb = (void*)_sccb;
  72
  73     sccb->h.length = sizeof(WriteEventData) + len;
  74     sccb->h.function_code = SCLP_FC_NORMAL_WRITE;
  75     sccb->ebh.length = sizeof(EventBufferHeader) + len;
  76     sccb->ebh.type = SCLP_EVENT_ASCII_CONSOLE_DATA;
  77     sccb->ebh.flags = 0;
  78     _memcpy(sccb->data, str, len);
  79
  80     sclp_service_call(SCLP_CMD_WRITE_EVENT_DATA, sccb);
  81 }