iPXE
x86_uart.c
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1 /*
2  * Copyright (C) 2014 Michael Brown <mbrown@fensystems.co.uk>.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License as
6  * published by the Free Software Foundation; either version 2 of the
7  * License, or any later version.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17  * 02110-1301, USA.
18  *
19  * You can also choose to distribute this program under the terms of
20  * the Unmodified Binary Distribution Licence (as given in the file
21  * COPYING.UBDL), provided that you have satisfied its requirements.
22  */
23 
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25 
26 /** @file
27  *
28  * 16550-compatible UART
29  *
30  */
31 
32 #include <errno.h>
33 #include <ipxe/uart.h>
34 
35 /** UART port bases */
36 static uint16_t uart_base[] = {
37  [COM1] = 0x3f8,
38  [COM2] = 0x2f8,
39  [COM3] = 0x3e8,
40  [COM4] = 0x2e8,
41 };
42 
43 /**
44  * Select UART port
45  *
46  * @v uart UART
47  * @v port Port number, or 0 to disable
48  * @ret rc Return status code
49  */
50 int uart_select ( struct uart *uart, unsigned int port ) {
51  int rc;
52 
53  /* Set new UART base */
54  if ( port >= ( sizeof ( uart_base ) / sizeof ( uart_base[0] ) ) ) {
55  rc = -ENODEV;
56  goto err;
57  }
58  uart->base = ( ( void * ) ( intptr_t ) uart_base[port] );
59 
60  /* Check that UART exists */
61  if ( ( rc = uart_exists ( uart ) ) != 0 )
62  goto err;
63 
64  return 0;
65 
66  err:
67  uart->base = NULL;
68  return rc;
69 }
struct arbelprm_rc_send_wqe rc
Definition: arbel.h:14
unsigned short uint16_t
Definition: stdint.h:11
int uart_exists(struct uart *uart)
Check for existence of UART.
Definition: uart.c:88
Definition: uart.h:92
Error codes.
A 16550-compatible UART.
Definition: uart.h:80
void * base
I/O port base address.
Definition: uart.h:82
unsigned long intptr_t
Definition: stdint.h:21
Definition: uart.h:91
u8 port
Port number.
Definition: CIB_PRM.h:31
Definition: uart.h:94
#define ENODEV
No such device.
Definition: errno.h:509
Definition: uart.h:93
16550-compatible UART
FILE_LICENCE(GPL2_OR_LATER_OR_UBDL)
static uint16_t uart_base[]
UART port bases.
Definition: x86_uart.c:36
#define NULL
NULL pointer (VOID *)
Definition: Base.h:362
int uart_select(struct uart *uart, unsigned int port)
Select UART port.
Definition: x86_uart.c:50