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 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 inline int hvc_rtas_write_console(uint32_t vtermno, const char *buf, 35 int count) 36 { 37 int 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 int hvc_rtas_read_console(uint32_t vtermno, char *buf, int count) 48 { 49 int i, c; 50 51 for (i = 0; i < count; i++) { 52 if (rtas_call(rtascons_get_char_token, 0, 2, &c)) 53 break; 54 55 buf[i] = c; 56 } 57 58 return i; 59 } 60 61 static const struct hv_ops hvc_rtas_get_put_ops = { 62 .get_chars = hvc_rtas_read_console, 63 .put_chars = hvc_rtas_write_console, 64 }; 65 66 static int __init hvc_rtas_init(void) 67 { 68 struct hvc_struct *hp; 69 70 if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE) 71 rtascons_put_char_token = rtas_token("put-term-char"); 72 if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE) 73 return -EIO; 74 75 if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE) 76 rtascons_get_char_token = rtas_token("get-term-char"); 77 if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE) 78 return -EIO; 79 80 BUG_ON(hvc_rtas_dev); 81 82 /* Allocate an hvc_struct for the console device we instantiated 83 * earlier. Save off hp so that we can return it on exit */ 84 hp = hvc_alloc(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops, 16); 85 if (IS_ERR(hp)) 86 return PTR_ERR(hp); 87 88 hvc_rtas_dev = hp; 89 90 return 0; 91 } 92 device_initcall(hvc_rtas_init); 93 94 /* This will happen prior to module init. There is no tty at this time? */ 95 static int __init hvc_rtas_console_init(void) 96 { 97 rtascons_put_char_token = rtas_token("put-term-char"); 98 if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE) 99 return -EIO; 100 101 rtascons_get_char_token = rtas_token("get-term-char"); 102 if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE) 103 return -EIO; 104 105 hvc_instantiate(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops); 106 add_preferred_console("hvc", 0, NULL); 107 108 return 0; 109 } 110 console_initcall(hvc_rtas_console_init); 111