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01e4d27355
Some board like Hisilicon D02 uses Synopsys DesignWare ABP UART, declare an OF early console for it, so early console device can be enabled with comand line "earlycon"(without option) via the "stdout-path" property in device-tree. Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Tested-by: Jon Mason <jon.mason@broadcom.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
175 lines
4.9 KiB
C
175 lines
4.9 KiB
C
/*
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* Early serial console for 8250/16550 devices
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*
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* (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
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* Bjorn Helgaas <bjorn.helgaas@hp.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Based on the 8250.c serial driver, Copyright (C) 2001 Russell King,
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* and on early_printk.c by Andi Kleen.
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*
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* This is for use before the serial driver has initialized, in
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* particular, before the UARTs have been discovered and named.
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* Instead of specifying the console device as, e.g., "ttyS0",
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* we locate the device directly by its MMIO or I/O port address.
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*
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* The user can specify the device directly, e.g.,
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* earlycon=uart8250,io,0x3f8,9600n8
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* earlycon=uart8250,mmio,0xff5e0000,115200n8
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* earlycon=uart8250,mmio32,0xff5e0000,115200n8
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* or
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* console=uart8250,io,0x3f8,9600n8
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* console=uart8250,mmio,0xff5e0000,115200n8
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* console=uart8250,mmio32,0xff5e0000,115200n8
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*/
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#include <linux/tty.h>
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#include <linux/init.h>
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#include <linux/console.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/serial_reg.h>
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#include <linux/serial.h>
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#include <linux/serial_8250.h>
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#include <asm/io.h>
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#include <asm/serial.h>
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static unsigned int __init serial8250_early_in(struct uart_port *port, int offset)
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{
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offset <<= port->regshift;
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switch (port->iotype) {
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case UPIO_MEM:
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return readb(port->membase + offset);
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case UPIO_MEM16:
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return readw(port->membase + offset);
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case UPIO_MEM32:
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return readl(port->membase + offset);
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case UPIO_MEM32BE:
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return ioread32be(port->membase + offset);
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case UPIO_PORT:
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return inb(port->iobase + offset);
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default:
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return 0;
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}
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}
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static void __init serial8250_early_out(struct uart_port *port, int offset, int value)
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{
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offset <<= port->regshift;
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switch (port->iotype) {
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case UPIO_MEM:
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writeb(value, port->membase + offset);
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break;
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case UPIO_MEM16:
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writew(value, port->membase + offset);
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break;
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case UPIO_MEM32:
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writel(value, port->membase + offset);
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break;
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case UPIO_MEM32BE:
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iowrite32be(value, port->membase + offset);
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break;
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case UPIO_PORT:
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outb(value, port->iobase + offset);
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break;
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}
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}
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#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
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static void __init serial_putc(struct uart_port *port, int c)
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{
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unsigned int status;
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serial8250_early_out(port, UART_TX, c);
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for (;;) {
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status = serial8250_early_in(port, UART_LSR);
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if ((status & BOTH_EMPTY) == BOTH_EMPTY)
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break;
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cpu_relax();
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}
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}
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static void __init early_serial8250_write(struct console *console,
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const char *s, unsigned int count)
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{
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struct earlycon_device *device = console->data;
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struct uart_port *port = &device->port;
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uart_console_write(port, s, count, serial_putc);
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}
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static void __init init_port(struct earlycon_device *device)
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{
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struct uart_port *port = &device->port;
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unsigned int divisor;
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unsigned char c;
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unsigned int ier;
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serial8250_early_out(port, UART_LCR, 0x3); /* 8n1 */
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ier = serial8250_early_in(port, UART_IER);
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serial8250_early_out(port, UART_IER, ier & UART_IER_UUE); /* no interrupt */
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serial8250_early_out(port, UART_FCR, 0); /* no fifo */
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serial8250_early_out(port, UART_MCR, 0x3); /* DTR + RTS */
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divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * device->baud);
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c = serial8250_early_in(port, UART_LCR);
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serial8250_early_out(port, UART_LCR, c | UART_LCR_DLAB);
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serial8250_early_out(port, UART_DLL, divisor & 0xff);
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serial8250_early_out(port, UART_DLM, (divisor >> 8) & 0xff);
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serial8250_early_out(port, UART_LCR, c & ~UART_LCR_DLAB);
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}
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int __init early_serial8250_setup(struct earlycon_device *device,
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const char *options)
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{
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if (!(device->port.membase || device->port.iobase))
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return -ENODEV;
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if (!device->baud) {
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struct uart_port *port = &device->port;
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unsigned int ier;
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/* assume the device was initialized, only mask interrupts */
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ier = serial8250_early_in(port, UART_IER);
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serial8250_early_out(port, UART_IER, ier & UART_IER_UUE);
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} else
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init_port(device);
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device->con->write = early_serial8250_write;
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return 0;
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}
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EARLYCON_DECLARE(uart8250, early_serial8250_setup);
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EARLYCON_DECLARE(uart, early_serial8250_setup);
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OF_EARLYCON_DECLARE(ns16550, "ns16550", early_serial8250_setup);
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OF_EARLYCON_DECLARE(ns16550a, "ns16550a", early_serial8250_setup);
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OF_EARLYCON_DECLARE(uart, "nvidia,tegra20-uart", early_serial8250_setup);
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OF_EARLYCON_DECLARE(uart, "snps,dw-apb-uart", early_serial8250_setup);
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#ifdef CONFIG_SERIAL_8250_OMAP
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static int __init early_omap8250_setup(struct earlycon_device *device,
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const char *options)
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{
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struct uart_port *port = &device->port;
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if (!(device->port.membase || device->port.iobase))
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return -ENODEV;
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port->regshift = 2;
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device->con->write = early_serial8250_write;
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return 0;
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}
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OF_EARLYCON_DECLARE(omap8250, "ti,omap2-uart", early_omap8250_setup);
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OF_EARLYCON_DECLARE(omap8250, "ti,omap3-uart", early_omap8250_setup);
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OF_EARLYCON_DECLARE(omap8250, "ti,omap4-uart", early_omap8250_setup);
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#endif
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