1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * hvconsole.c 4 * Copyright (C) 2004 Hollis Blanchard, IBM Corporation 5 * Copyright (C) 2004 IBM Corporation 6 * 7 * Additional Author(s): 8 * Ryan S. Arnold <rsa@us.ibm.com> 9 * 10 * LPAR console support. 11 */ 12 13 #include <linux/kernel.h> 14 #include <linux/export.h> 15 #include <linux/errno.h> 16 #include <asm/hvcall.h> 17 #include <asm/hvconsole.h> 18 #include <asm/plpar_wrappers.h> 19 20 /** 21 * hvc_get_chars - retrieve characters from firmware for denoted vterm adapter 22 * @vtermno: The vtermno or unit_address of the adapter from which to fetch the 23 * data. 24 * @buf: The character buffer into which to put the character data fetched from 25 * firmware. 26 * @count: not used? 27 */ 28 ssize_t hvc_get_chars(uint32_t vtermno, u8 *buf, size_t count) 29 { 30 long ret; 31 unsigned long retbuf[PLPAR_HCALL_BUFSIZE]; 32 unsigned long *lbuf = (unsigned long *)buf; 33 34 ret = plpar_hcall(H_GET_TERM_CHAR, retbuf, vtermno); 35 lbuf[0] = be64_to_cpu(retbuf[1]); 36 lbuf[1] = be64_to_cpu(retbuf[2]); 37 38 if (ret == H_SUCCESS) 39 return retbuf[0]; 40 41 return 0; 42 } 43 44 EXPORT_SYMBOL(hvc_get_chars); 45 46 47 /** 48 * hvc_put_chars: send characters to firmware for denoted vterm adapter 49 * @vtermno: The vtermno or unit_address of the adapter from which the data 50 * originated. 51 * @buf: The character buffer that contains the character data to send to 52 * firmware. Must be at least 16 bytes, even if count is less than 16. 53 * @count: Send this number of characters. 54 */ 55 ssize_t hvc_put_chars(uint32_t vtermno, const u8 *buf, size_t count) 56 { 57 unsigned long *lbuf = (unsigned long *) buf; 58 long ret; 59 60 61 /* hcall will ret H_PARAMETER if 'count' exceeds firmware max.*/ 62 if (count > MAX_VIO_PUT_CHARS) 63 count = MAX_VIO_PUT_CHARS; 64 65 ret = plpar_hcall_norets(H_PUT_TERM_CHAR, vtermno, count, 66 cpu_to_be64(lbuf[0]), 67 cpu_to_be64(lbuf[1])); 68 if (ret == H_SUCCESS) 69 return count; 70 if (ret == H_BUSY) 71 return -EAGAIN; 72 return -EIO; 73 } 74 75 EXPORT_SYMBOL(hvc_put_chars); 76