kernel/arch/ia32xen/src/drivers/xconsole.c

   1 /*
   2  * Copyright (c) 2006 Martin Decky
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup ia32xen
  30  * @{
  31  */
  32 /**
  33  * @file
  34  * @brief ia32xen console driver.
  35  */
  36
  37 #include <arch/drivers/xconsole.h>
  38 #include <putchar.h>
  39 #include <console/chardev.h>
  40 #include <console/console.h>
  41 #include <arch/hypercall.h>
  42
  43 #define MASK_INDEX(index, ring) ((index) & (sizeof(ring) - 1))
  44
  45 static void xen_putchar(chardev_t *d, const char ch);
  46
  47 chardev_t xen_console;
  48 static chardev_operations_t xen_ops = {
  49         .write = xen_putchar
  50 };
  51
  52 void xen_console_init(void)
  53 {
  54         chardev_initialize("xen_out", &xen_console, &xen_ops);
  55         stdout = &xen_console;
  56 }
  57
  58 void xen_putchar(chardev_t *d, const char ch)
  59 {
  60         if (start_info.console.domU.evtchn != 0) {
  61                 uint32_t cons = console_page.out_cons;
  62                 uint32_t prod = console_page.out_prod;
  63
  64                 memory_barrier();
  65
  66                 if ((prod - cons) > sizeof(console_page.out))
  67                         return;
  68
  69                 if (ch == '\n')
  70                         console_page.out[MASK_INDEX(prod++, console_page.out)] = '\r';
  71                 console_page.out[MASK_INDEX(prod++, console_page.out)] = ch;
  72
  73                 write_barrier();
  74
  75                 console_page.out_prod = prod;
  76
  77                 xen_notify_remote(start_info.console.domU.evtchn);
  78         } else
  79                 xen_console_io(CONSOLE_IO_WRITE, 1, &ch);
  80 }
  81
  82 /** @}
  83  */