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1// SPDX-License-Identifier: GPL-2.0+2/*3 * IBM RTAS driver interface to hvc_console.c4 *5 * (C) Copyright IBM Corporation 2001-20056 * (C) Copyright Red Hat, Inc. 20057 *8 * Author(s): Maximino Augilar <IBM STI Design Center>9 * : Ryan S. Arnold <rsa@us.ibm.com>10 * : Utz Bacher <utz.bacher@de.ibm.com>11 * : David Woodhouse <dwmw2@infradead.org>12 *13 * inspired by drivers/char/hvc_console.c14 * written by Anton Blanchard and Paul Mackerras15 */16 17#include <linux/console.h>18#include <linux/delay.h>19#include <linux/err.h>20#include <linux/init.h>21#include <linux/moduleparam.h>22#include <linux/types.h>23 24#include <asm/irq.h>25#include <asm/rtas.h>26#include "hvc_console.h"27 28#define hvc_rtas_cookie 0x67781e1529static struct hvc_struct *hvc_rtas_dev;30 31static int rtascons_put_char_token = RTAS_UNKNOWN_SERVICE;32static int rtascons_get_char_token = RTAS_UNKNOWN_SERVICE;33 34static ssize_t hvc_rtas_write_console(uint32_t vtermno, const u8 *buf,35 size_t count)36{37 size_t i;38 39 for (i = 0; i < count; i++) {40 if (rtas_call(rtascons_put_char_token, 1, 1, NULL, buf[i]))41 break;42 }43 44 return i;45}46 47static ssize_t hvc_rtas_read_console(uint32_t vtermno, u8 *buf, size_t count)48{49 size_t i;50 int c;51 52 for (i = 0; i < count; i++) {53 if (rtas_call(rtascons_get_char_token, 0, 2, &c))54 break;55 56 buf[i] = c;57 }58 59 return i;60}61 62static const struct hv_ops hvc_rtas_get_put_ops = {63 .get_chars = hvc_rtas_read_console,64 .put_chars = hvc_rtas_write_console,65};66 67static int __init hvc_rtas_init(void)68{69 struct hvc_struct *hp;70 71 if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)72 rtascons_put_char_token = rtas_token("put-term-char");73 if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)74 return -EIO;75 76 if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)77 rtascons_get_char_token = rtas_token("get-term-char");78 if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)79 return -EIO;80 81 BUG_ON(hvc_rtas_dev);82 83 /* Allocate an hvc_struct for the console device we instantiated84 * earlier. Save off hp so that we can return it on exit */85 hp = hvc_alloc(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops, 16);86 if (IS_ERR(hp))87 return PTR_ERR(hp);88 89 hvc_rtas_dev = hp;90 91 return 0;92}93device_initcall(hvc_rtas_init);94 95/* This will happen prior to module init. There is no tty at this time? */96static int __init hvc_rtas_console_init(void)97{98 rtascons_put_char_token = rtas_token("put-term-char");99 if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)100 return -EIO;101 102 rtascons_get_char_token = rtas_token("get-term-char");103 if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)104 return -EIO;105 106 hvc_instantiate(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops);107 add_preferred_console("hvc", 0, NULL);108 109 return 0;110}111console_initcall(hvc_rtas_console_init);112