1 // SPDX-License-Identifier: GPL-2.0-or-later
2 
3 /*
4  * IBM ASM Service Processor Device Driver
5  *
6  * Copyright (C) IBM Corporation, 2004
7  *
8  * Author: Max Asböck <amax@us.ibm.com>
9  */
10 
11 #include <linux/termios.h>
12 #include <linux/tty.h>
13 #include <linux/serial_core.h>
14 #include <linux/serial_reg.h>
15 #include <linux/serial_8250.h>
16 #include "ibmasm.h"
17 #include "lowlevel.h"
18 
19 
ibmasm_register_uart(struct service_processor * sp)20 void ibmasm_register_uart(struct service_processor *sp)
21 {
22 	struct uart_8250_port uart;
23 	void __iomem *iomem_base;
24 
25 	iomem_base = sp->base_address + SCOUT_COM_B_BASE;
26 
27 	/* read the uart scratch register to determine if the UART
28 	 * is dedicated to the service processor or if the OS can use it
29 	 */
30 	if (0 == readl(iomem_base + UART_SCR)) {
31 		dev_info(sp->dev, "IBM SP UART not registered, owned by service processor\n");
32 		sp->serial_line = -1;
33 		return;
34 	}
35 
36 	memset(&uart, 0, sizeof(uart));
37 	uart.port.irq		= sp->irq;
38 	uart.port.uartclk	= 3686400;
39 	uart.port.flags		= UPF_SHARE_IRQ;
40 	uart.port.iotype	= UPIO_MEM;
41 	uart.port.membase	= iomem_base;
42 
43 	sp->serial_line = serial8250_register_8250_port(&uart);
44 	if (sp->serial_line < 0) {
45 		dev_err(sp->dev, "Failed to register serial port\n");
46 		return;
47 	}
48 	enable_uart_interrupts(sp->base_address);
49 }
50 
ibmasm_unregister_uart(struct service_processor * sp)51 void ibmasm_unregister_uart(struct service_processor *sp)
52 {
53 	if (sp->serial_line < 0)
54 		return;
55 
56 	disable_uart_interrupts(sp->base_address);
57 	serial8250_unregister_port(sp->serial_line);
58 }
59