/*
 * SCLP ASCII access driver
 *
 * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or (at
 * your option) any later version. See the COPYING file in the top-level
 * directory.
 */

#include "s390-ccw.h"
#include "sclp.h"

static char _sccb[PAGE_SIZE] __attribute__((__aligned__(4096)));

/* Perform service call. Return 0 on success, non-zero otherwise. */
static int sclp_service_call(unsigned int command, void *sccb)
{
        int cc;

        asm volatile(
                "       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
                "       ipm     %0\n"
                "       srl     %0,28"
                : "=&d" (cc) : "d" (command), "a" (__pa(sccb))
                : "cc", "memory");
        if (cc == 3)
                return -EIO;
        if (cc == 2)
                return -EBUSY;
        return 0;
}

static void sclp_set_write_mask(void)
{
    WriteEventMask *sccb = (void*)_sccb;

    sccb->h.length = sizeof(WriteEventMask);
    sccb->mask_length = sizeof(unsigned int);
    sccb->receive_mask = SCLP_EVENT_MASK_MSG_ASCII;
    sccb->cp_receive_mask = SCLP_EVENT_MASK_MSG_ASCII;
    sccb->send_mask = SCLP_EVENT_MASK_MSG_ASCII;
    sccb->cp_send_mask = SCLP_EVENT_MASK_MSG_ASCII;

    sclp_service_call(SCLP_CMD_WRITE_EVENT_MASK, sccb);
}

void sclp_setup(void)
{
    sclp_set_write_mask();
}

static int _strlen(const char *str)
{
    int i;
    for (i = 0; *str; i++)
        str++;
    return i;
}

static void _memcpy(char *dest, const char *src, int len)
{
    int i;
    for (i = 0; i < len; i++)
        dest[i] = src[i];
}

void sclp_print(const char *str)
{
    int len = _strlen(str);
    WriteEventData *sccb = (void*)_sccb;

    sccb->h.length = sizeof(WriteEventData) + len;
    sccb->h.function_code = SCLP_FC_NORMAL_WRITE;
    sccb->ebh.length = sizeof(EventBufferHeader) + len;
    sccb->ebh.type = SCLP_EVENT_ASCII_CONSOLE_DATA;
    sccb->ebh.flags = 0;
    _memcpy(sccb->data, str, len);

    sclp_service_call(SCLP_CMD_WRITE_EVENT_DATA, sccb);
}