serial.c

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/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2004-2007 Cavium Networks
 */
#include <linux/console.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/serial.h>
#include <linux/serial_8250.h>
#include <linux/serial_reg.h>
#include <linux/tty.h>
#include <linux/irq.h>

#include <asm/time.h>

#include <asm/octeon/octeon.h>

#define DEBUG_UART 1

unsigned int octeon_serial_in(struct uart_port *up, int offset)
{
    int rv = cvmx_read_csr((uint64_t)(up->membase + (offset << 3)));
    if (offset == UART_IIR && (rv & 0xf) == 7) {
        /* Busy interrupt, read the USR (39) and try again. */
        cvmx_read_csr((uint64_t)(up->membase + (39 << 3)));
        rv = cvmx_read_csr((uint64_t)(up->membase + (offset << 3)));
    }
    return rv;
}

void octeon_serial_out(struct uart_port *up, int offset, int value)
{
    /*
     * If bits 6 or 7 of the OCTEON UART's LCR are set, it quits
     * working.
     */
    if (offset == UART_LCR)
        value &= 0x9f;
    cvmx_write_csr((uint64_t)(up->membase + (offset << 3)), (u8)value);
}

static int __devinit octeon_serial_probe(struct platform_device *pdev)
{
    int irq, res;
    struct resource *res_mem;
    struct uart_8250_port up;

    /* All adaptors have an irq.  */
    irq = platform_get_irq(pdev, 0);
    if (irq < 0)
        return irq;

    memset(&up, 0, sizeof(up));

    up.port.flags = ASYNC_SKIP_TEST | UPF_SHARE_IRQ | UPF_FIXED_TYPE;
    up.port.type = PORT_OCTEON;
    up.port.iotype = UPIO_MEM;
    up.port.regshift = 3;
    up.port.dev = &pdev->dev;

    if (octeon_is_simulation())
        /* Make simulator output fast*/
        up.port.uartclk = 115200 * 16;
    else
        up.port.uartclk = octeon_get_io_clock_rate();

    up.port.serial_in = octeon_serial_in;
    up.port.serial_out = octeon_serial_out;
    up.port.irq = irq;

    res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (res_mem == NULL) {
        dev_err(&pdev->dev, "found no memory resource\n");
        return -ENXIO;
    }
    up.port.mapbase = res_mem->start;
    up.port.membase = ioremap(res_mem->start, resource_size(res_mem));

    res = serial8250_register_8250_port(&up);

    return res >= 0 ? 0 : res;
}

static struct of_device_id octeon_serial_match[] = {
    {
        .compatible = "cavium,octeon-3860-uart",
    },
    {},
};
MODULE_DEVICE_TABLE(of, octeon_serial_match);

static struct platform_driver octeon_serial_driver = {
    .probe      = octeon_serial_probe,
    .driver     = {
        .owner  = THIS_MODULE,
        .name   = "octeon_serial",
        .of_match_table = octeon_serial_match,
    },
};

static int __init octeon_serial_init(void)
{
    return platform_driver_register(&octeon_serial_driver);
}
late_initcall(octeon_serial_init);