source: mainline/uspace/srv/hw/char/s3c24xx_uart/s3c24xx_uart.c@ a9b5b5f

/*
 * Copyright (c) 2010 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup driver_serial
 * @{
 */
/**
 * @file
 * @brief Samsung S3C24xx on-chip UART driver.
 *
 * This UART is present on the Samsung S3C24xx CPU (on the gta02 platform).
 */

#include <ddi.h>
#include <libarch/ddi.h>
#include <devmap.h>
#include <ipc/ipc.h>
#include <ipc/char.h>
#include <async.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sysinfo.h>
#include <errno.h>

#include "s3c24xx_uart.h"

#define NAME "s3c24ser"
#define NAMESPACE "char"

/* Bits in UTRSTAT register */
#define S3C24XX_UTRSTAT_TX_EMPTY        0x4
#define S3C24XX_UTRSTAT_RDATA           0x1

static irq_cmd_t uart_irq_cmds[] = {
        {
                .cmd = CMD_ACCEPT
        }
};

static irq_code_t uart_irq_code = {
        sizeof(uart_irq_cmds) / sizeof(irq_cmd_t),
        uart_irq_cmds
};

/** S3C24xx UART instance structure */
static s3c24xx_uart_t *uart;

static void s3c24xx_uart_connection(ipc_callid_t iid, ipc_call_t *icall);
static void s3c24xx_uart_irq_handler(ipc_callid_t iid, ipc_call_t *call);
static int s3c24xx_uart_init(s3c24xx_uart_t *uart);
static void s3c24xx_uart_sendb(s3c24xx_uart_t *uart, uint8_t byte);

int main(int argc, char *argv[])
{
        int rc;

        printf(NAME ": S3C24xx on-chip UART driver\n");

        rc = devmap_driver_register(NAME, s3c24xx_uart_connection);
        if (rc < 0) {
                printf(NAME ": Unable to register driver.\n");
                return -1;
        }

        uart = malloc(sizeof(s3c24xx_uart_t));
        if (uart == NULL)
                return -1;

        if (s3c24xx_uart_init(uart) != EOK)
                return -1;

        rc = devmap_device_register(NAMESPACE "/" NAME, &uart->dev_handle);
        if (rc != EOK) {
                devmap_hangup_phone(DEVMAP_DRIVER);
                printf(NAME ": Unable to register device %s.\n");
                return -1;
        }

        printf(NAME ": Registered device %s.\n", NAMESPACE "/" NAME);

        printf(NAME ": Accepting connections\n");
        task_retval(0);
        async_manager();

        /* Not reached */
        return 0;
}

/** Character device connection handler. */
static void s3c24xx_uart_connection(ipc_callid_t iid, ipc_call_t *icall)
{
        ipc_callid_t callid;
        ipc_call_t call;
        ipcarg_t method;
        int retval;

        /* Answer the IPC_M_CONNECT_ME_TO call. */
        ipc_answer_0(iid, EOK);

        while (1) {
                callid = async_get_call(&call);
                method = IPC_GET_METHOD(call);
                switch (method) {
                case IPC_M_PHONE_HUNGUP:
                        /* The other side has hung up. */
                        ipc_answer_0(callid, EOK);
                        return;
                case IPC_M_CONNECT_TO_ME:
                        printf(NAME ": creating callback connection\n");
                        uart->client_phone = IPC_GET_ARG5(call);
                        retval = 0;
                        break;
                case CHAR_WRITE_BYTE:
                        printf(NAME ": write %d to device\n",
                            IPC_GET_ARG1(call));
                        s3c24xx_uart_sendb(uart, (uint8_t) IPC_GET_ARG1(call));
                        retval = 0;
                        break;
                default:
                        retval = EINVAL;
                        break;
                }
                ipc_answer_0(callid, retval);
        }
}

static void s3c24xx_uart_irq_handler(ipc_callid_t iid, ipc_call_t *call)
{
        (void) iid; (void) call;

        if ((pio_read_32(&uart->io->utrstat) & S3C24XX_UTRSTAT_RDATA) != 0) {
                uint32_t data = pio_read_32(&uart->io->urxh) & 0xff;

                if (uart->client_phone != -1) {
                        async_msg_1(uart->client_phone, CHAR_NOTIF_BYTE,
                            data);
                }
        }
}

/** Initialize S3C24xx on-chip UART. */
static int s3c24xx_uart_init(s3c24xx_uart_t *uart)
{
        void *vaddr;
        sysarg_t inr;

        if (sysinfo_get_value("s3c24xx_uart.address.physical",
            &uart->paddr) != EOK)
                return -1;

        if (pio_enable((void *) uart->paddr, sizeof(s3c24xx_uart_io_t),
            &vaddr) != 0)
                return -1;

        if (sysinfo_get_value("s3c24xx_uart.inr", &inr) != EOK)
                return -1;

        uart->io = vaddr;
        uart->client_phone = -1;

        printf(NAME ": device at physical address 0x%x, inr %d.\n",
            uart->paddr, inr);

        async_set_interrupt_received(s3c24xx_uart_irq_handler);

        ipc_register_irq(inr, device_assign_devno(), 0, &uart_irq_code);

        /* Disable FIFO */
        pio_write_32(&uart->io->ufcon,
            pio_read_32(&uart->io->ufcon) & ~0x01);

        /* Set RX interrupt to pulse mode */
        pio_write_32(&uart->io->ucon,
            pio_read_32(&uart->io->ucon) & ~(1 << 8));

        return EOK;
}

/** Send a byte to the UART. */
static void s3c24xx_uart_sendb(s3c24xx_uart_t *uart, uint8_t byte)
{
        /* Wait for transmitter to be empty. */
        while ((pio_read_32(&uart->io->utrstat) & S3C24XX_UTRSTAT_TX_EMPTY) == 0)
                ;

        pio_write_32(&uart->io->utxh, byte);
}

/** @}
 */