misc/ibmasm/uart.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002
0003 /*
0004  * IBM ASM Service Processor Device Driver
0005  *
0006  * Copyright (C) IBM Corporation, 2004
0007  *
0008  * Author: Max Asböck <amax@us.ibm.com>
0009  */
0010
0011 #include <linux/termios.h>
0012 #include <linux/tty.h>
0013 #include <linux/serial_core.h>
0014 #include <linux/serial_reg.h>
0015 #include <linux/serial_8250.h>
0016 #include "ibmasm.h"
0017 #include "lowlevel.h"
0018
0019
0020 void ibmasm_register_uart(struct service_processor *sp)
0021 {
0022     struct uart_8250_port uart;
0023     void __iomem *iomem_base;
0024
0025     iomem_base = sp->base_address + SCOUT_COM_B_BASE;
0026
0027     /* read the uart scratch register to determine if the UART
0028      * is dedicated to the service processor or if the OS can use it
0029      */
0030     if (0 == readl(iomem_base + UART_SCR)) {
0031         dev_info(sp->dev, "IBM SP UART not registered, owned by service processor\n");
0032         sp->serial_line = -1;
0033         return;
0034     }
0035
0036     memset(&uart, 0, sizeof(uart));
0037     uart.port.irq       = sp->irq;
0038     uart.port.uartclk   = 3686400;
0039     uart.port.flags     = UPF_SHARE_IRQ;
0040     uart.port.iotype    = UPIO_MEM;
0041     uart.port.membase   = iomem_base;
0042
0043     sp->serial_line = serial8250_register_8250_port(&uart);
0044     if (sp->serial_line < 0) {
0045         dev_err(sp->dev, "Failed to register serial port\n");
0046         return;
0047     }
0048     enable_uart_interrupts(sp->base_address);
0049 }
0050
0051 void ibmasm_unregister_uart(struct service_processor *sp)
0052 {
0053     if (sp->serial_line < 0)
0054         return;
0055
0056     disable_uart_interrupts(sp->base_address);
0057     serial8250_unregister_port(sp->serial_line);
0058 }