xref: /openbmc/linux/drivers/misc/ibmasm/uart.c (revision 293d5b43)
1 
2 /*
3  * IBM ASM Service Processor Device Driver
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18  *
19  * Copyright (C) IBM Corporation, 2004
20  *
21  * Author: Max Asböck <amax@us.ibm.com>
22  *
23  */
24 
25 #include <linux/termios.h>
26 #include <linux/tty.h>
27 #include <linux/serial_core.h>
28 #include <linux/serial_reg.h>
29 #include <linux/serial_8250.h>
30 #include "ibmasm.h"
31 #include "lowlevel.h"
32 
33 
34 void ibmasm_register_uart(struct service_processor *sp)
35 {
36 	struct uart_8250_port uart;
37 	void __iomem *iomem_base;
38 
39 	iomem_base = sp->base_address + SCOUT_COM_B_BASE;
40 
41 	/* read the uart scratch register to determine if the UART
42 	 * is dedicated to the service processor or if the OS can use it
43 	 */
44 	if (0 == readl(iomem_base + UART_SCR)) {
45 		dev_info(sp->dev, "IBM SP UART not registered, owned by service processor\n");
46 		sp->serial_line = -1;
47 		return;
48 	}
49 
50 	memset(&uart, 0, sizeof(uart));
51 	uart.port.irq		= sp->irq;
52 	uart.port.uartclk	= 3686400;
53 	uart.port.flags		= UPF_SHARE_IRQ;
54 	uart.port.iotype	= UPIO_MEM;
55 	uart.port.membase	= iomem_base;
56 
57 	sp->serial_line = serial8250_register_8250_port(&uart);
58 	if (sp->serial_line < 0) {
59 		dev_err(sp->dev, "Failed to register serial port\n");
60 		return;
61 	}
62 	enable_uart_interrupts(sp->base_address);
63 }
64 
65 void ibmasm_unregister_uart(struct service_processor *sp)
66 {
67 	if (sp->serial_line < 0)
68 		return;
69 
70 	disable_uart_interrupts(sp->base_address);
71 	serial8250_unregister_port(sp->serial_line);
72 }
73