1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * IBM RTAS driver interface to hvc_console.c 4 * 5 * (C) Copyright IBM Corporation 2001-2005 6 * (C) Copyright Red Hat, Inc. 2005 7 * 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.c 14 * written by Anton Blanchard and Paul Mackerras 15 */ 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 0x67781e15 29 static struct hvc_struct *hvc_rtas_dev; 30 31 static int rtascons_put_char_token = RTAS_UNKNOWN_SERVICE; 32 static int rtascons_get_char_token = RTAS_UNKNOWN_SERVICE; 33 34 static 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 47 static 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 62 static 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 67 static 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 instantiated 84 * 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 } 93 device_initcall(hvc_rtas_init); 94 95 /* This will happen prior to module init. There is no tty at this time? */ 96 static 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 } 111 console_initcall(hvc_rtas_console_init); 112