drivers/tty/hvc/hvc_riscv_sbi.c

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (C) 2008 David Gibson, IBM Corporation
   4  * Copyright (C) 2012 Regents of the University of California
   5  * Copyright (C) 2017 SiFive
   6  */
   7
   8 #include <linux/console.h>
   9 #include <linux/err.h>
  10 #include <linux/init.h>
  11 #include <linux/moduleparam.h>
  12 #include <linux/types.h>
  13
  14 #include <asm/sbi.h>
  15
  16 #include "hvc_console.h"
  17
  18 static ssize_t hvc_sbi_tty_put(uint32_t vtermno, const u8 *buf, size_t count)
  19 {
  20         size_t i;
  21
  22         for (i = 0; i < count; i++)
  23                 sbi_console_putchar(buf[i]);
  24
  25         return i;
  26 }
  27
  28 static ssize_t hvc_sbi_tty_get(uint32_t vtermno, u8 *buf, size_t count)
  29 {
  30         size_t i;
  31         int c;
  32
  33         for (i = 0; i < count; i++) {
  34                 c = sbi_console_getchar();
  35                 if (c < 0)
  36                         break;
  37                 buf[i] = c;
  38         }
  39
  40         return i;
  41 }
  42
  43 static const struct hv_ops hvc_sbi_v01_ops = {
  44         .get_chars = hvc_sbi_tty_get,
  45         .put_chars = hvc_sbi_tty_put,
  46 };
  47
  48 static ssize_t hvc_sbi_dbcn_tty_put(uint32_t vtermno, const u8 *buf, size_t count)
  49 {
  50         return sbi_debug_console_write(buf, count);
  51 }
  52
  53 static ssize_t hvc_sbi_dbcn_tty_get(uint32_t vtermno, u8 *buf, size_t count)
  54 {
  55         return sbi_debug_console_read(buf, count);
  56 }
  57
  58 static const struct hv_ops hvc_sbi_dbcn_ops = {
  59         .put_chars = hvc_sbi_dbcn_tty_put,
  60         .get_chars = hvc_sbi_dbcn_tty_get,
  61 };
  62
  63 static int __init hvc_sbi_init(void)
  64 {
  65         int err;
  66
  67         if (sbi_debug_console_available) {
  68                 err = PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_dbcn_ops, 256));
  69                 if (err)
  70                         return err;
  71                 hvc_instantiate(0, 0, &hvc_sbi_dbcn_ops);
  72         } else if (IS_ENABLED(CONFIG_RISCV_SBI_V01)) {
  73                 err = PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_v01_ops, 256));
  74                 if (err)
  75                         return err;
  76                 hvc_instantiate(0, 0, &hvc_sbi_v01_ops);
  77         } else {
  78                 return -ENODEV;
  79         }
  80
  81         return 0;
  82 }
  83 device_initcall(hvc_sbi_init);