source: mainline/uspace/srv/drivers/serial/serial.c@ f4ef3c2

/*
 * Copyright (c) 2010 Lenka Trochtova
 * 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.
 */

/**
 * @defgroup serial Serial port driver.
 * @brief HelenOS serial port driver.
 * @{
 */

/** @file
 */

#include <assert.h>
#include <stdio.h>
#include <errno.h>
#include <bool.h>
#include <fibril_synch.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <macros.h>
#include <malloc.h>
#include <dirent.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <ddi.h>
#include <libarch/ddi.h>

#include <driver.h>
#include <char.h>
#include <resource.h>

#include <devman.h>
#include <ipc/devman.h>
#include <device/hw_res.h>
#include <ipc/serial_ctl.h>

#include "cyclic_buffer.h"

#define NAME "serial"

#define REG_COUNT 7
#define MAX_BAUD_RATE 115200

typedef struct serial_dev_data {
        bool client_connected;
        int irq;
        uint32_t io_addr;
        ioport8_t *port;
        cyclic_buffer_t input_buffer;
        fibril_mutex_t mutex;           
} serial_dev_data_t;

static serial_dev_data_t * create_serial_dev_data()
{
        serial_dev_data_t *data = (serial_dev_data_t *)malloc(sizeof(serial_dev_data_t));
        if (NULL != data) {
                memset(data, 0, sizeof(serial_dev_data_t));
                fibril_mutex_initialize(&data->mutex);
        }
        return data;    
}

static void delete_serial_dev_data(serial_dev_data_t *data) 
{
        if (NULL != data) {
                free(data);
        }
}

static bool serial_received(ioport8_t *port) 
{
   return (pio_read_8(port + 5) & 1) != 0;
}

static uint8_t serial_read_8(ioport8_t *port) 
{
        return pio_read_8(port);
}

static bool is_transmit_empty(ioport8_t *port) 
{
   return (pio_read_8(port + 5) & 0x20) != 0;
}

static void serial_write_8(ioport8_t *port, uint8_t c) 
{
        while (!is_transmit_empty(port)) 
                ;
        
        pio_write_8(port, c);
}

static int serial_read(device_t *dev, char *buf, size_t count) 
{
        printf(NAME ": serial_read %s\n", dev->name);
        
        int ret = 0;
        
        serial_dev_data_t *data = (serial_dev_data_t *)dev->driver_data;
        fibril_mutex_lock(&data->mutex);
        
        while (!buf_is_empty(&data->input_buffer) && ret < count) {
                buf[ret] = (char)buf_pop_front(&data->input_buffer);
                ret++;
        }
        
        fibril_mutex_unlock(&data->mutex);
        
        return ret;
}

static inline void serial_putchar(serial_dev_data_t *data, uint8_t c)
{       
        fibril_mutex_lock(&data->mutex);
        serial_write_8(data->port, c);  
        fibril_mutex_unlock(&data->mutex);
}

static int serial_write(device_t *dev, char *buf, size_t count) 
{
        serial_dev_data_t *data = (serial_dev_data_t *)dev->driver_data;
        
        size_t idx;
        for (idx = 0; idx < count; idx++) {
                serial_putchar(data, (uint8_t)buf[idx]);
        }
        
        return 0;
}

static device_class_t serial_dev_class;

static char_iface_t serial_char_iface = {
        .read = &serial_read,
        .write = &serial_write
};

static int serial_add_device(device_t *dev);

/** The serial port device driver's standard operations.
 */
static driver_ops_t serial_ops = {
        .add_device = &serial_add_device
};

/** The serial port device driver structure. 
 */
static driver_t serial_driver = {
        .name = NAME,
        .driver_ops = &serial_ops
};

static void serial_dev_cleanup(device_t *dev)
{
        if (NULL != dev->driver_data) {
                delete_serial_dev_data((serial_dev_data_t*)dev->driver_data);   
                dev->driver_data = NULL;
        }
        
        if (dev->parent_phone > 0) {
                ipc_hangup(dev->parent_phone);
                dev->parent_phone = 0;
        }       
}

static bool serial_pio_enable(device_t *dev)
{
        printf(NAME ": serial_pio_enable %s\n", dev->name);
        
        serial_dev_data_t *data = (serial_dev_data_t *)dev->driver_data;
        
        // Gain control over port's registers.
        if (pio_enable((void *)data->io_addr, REG_COUNT, (void **)(&data->port))) {  
                printf(NAME ": error - cannot gain the port %lx for device %s.\n", data->io_addr, dev->name);
                return false;
        }
        
        return true;
}

static bool serial_dev_probe(device_t *dev)
{
        printf(NAME ": serial_dev_probe %s\n", dev->name);
        
        serial_dev_data_t *data = (serial_dev_data_t *)dev->driver_data;
        ioport8_t *port_addr = data->port;      
        bool res = true;
        uint8_t olddata;
        
        olddata = pio_read_8(port_addr + 4);
        
        pio_write_8(port_addr + 4, 0x10);
        if (pio_read_8(port_addr + 6) & 0xf0) {
                res = false;
        }
        
        pio_write_8(port_addr + 4, 0x1f);
        if ((pio_read_8(port_addr + 6) & 0xf0) != 0xf0) {
                res = false;
        }
        
        pio_write_8(port_addr + 4, olddata);
        
        if (!res) {
                printf(NAME ": device %s is not present.\n", dev->name);
        }
        
        return res;     
}

static int serial_dev_initialize(device_t *dev)
{
        printf(NAME ": serial_dev_initialize %s\n", dev->name);
        
        int ret = EOK;
        hw_resource_list_t hw_resources;
        memset(&hw_resources, 0, sizeof(hw_resource_list_t));
        
        // allocate driver data for the device
        serial_dev_data_t *data = create_serial_dev_data();     
        if (NULL == data) {
                return ENOMEM;
        }
        dev->driver_data = data;
        
        // connect to the parent's driver
        dev->parent_phone = devman_parent_device_connect(dev->handle,  IPC_FLAG_BLOCKING);
        if (dev->parent_phone <= 0) {
                printf(NAME ": failed to connect to the parent driver of the device %s.\n", dev->name);
                ret = EPARTY;
                goto failed;
        }
        
        // get hw resources
        
        if (!get_hw_resources(dev->parent_phone, &hw_resources)) {
                printf(NAME ": failed to get hw resources for the device %s.\n", dev->name);
                ret = EPARTY;
                goto failed;
        }       
        
        size_t i;
        hw_resource_t *res;
        bool irq = false;
        bool ioport = false;
        
        for (i = 0; i < hw_resources.count; i++) {
                res = &hw_resources.resources[i];
                switch (res->type) {
                case INTERRUPT:
                        data->irq = res->res.interrupt.irq;
                        irq = true;
                        printf(NAME ": the %s device was asigned irq = 0x%x.\n", dev->name, data->irq);
                        break;
                case IO_RANGE:
                        data->io_addr = res->res.io_range.address;
                        if (res->res.io_range.size < REG_COUNT) {
                                printf(NAME ": i/o range assigned to the device %s is too small.\n", dev->name);
                                ret = EPARTY;
                                goto failed;
                        }
                        ioport = true;
                        printf(NAME ": the %s device was asigned i/o address = 0x%x.\n", dev->name, data->io_addr);
                        break;  
                default:
                        break;
                }
        }
        
        if (!irq || !ioport) {
                printf(NAME ": missing hw resource(s) for the device %s.\n", dev->name);
                ret = EPARTY;
                goto failed;
        }               
        
        clean_hw_resource_list(&hw_resources);
        return ret;
        
failed:
        serial_dev_cleanup(dev);        
        clean_hw_resource_list(&hw_resources);  
        return ret;     
}

static inline void serial_port_interrupts_enable(ioport8_t *port)
{       
        pio_write_8(port + 1 , 0x01);   // Interrupt when data received
        pio_write_8(port + 4, 0x0B);    
}

static inline void serial_port_interrupts_disable(ioport8_t *port)
{
        pio_write_8(port + 1, 0x00);    // Disable all interrupts
}

static int serial_interrupt_enable(device_t *dev)
{
        serial_dev_data_t *data = (serial_dev_data_t *)dev->driver_data;
        
        int res;
        // enable interrupt globally    
        if (EOK != (res = interrupt_enable(data->irq))) {
                return res;
        }
        
        // enable interrupt on the serial port
        serial_port_interrupts_enable(data->port);
        
        return EOK;
}

static int serial_port_set_baud_rate(ioport8_t *port, unsigned int baud_rate)
{
        uint16_t divisor;
        uint8_t div_low, div_high;
        
        if (50 > baud_rate || 0 != MAX_BAUD_RATE % baud_rate) {
                return EINVAL; 
        }
        
        divisor = MAX_BAUD_RATE / baud_rate;
        div_low = (uint8_t)divisor;
        div_high = (uint8_t)(divisor >> 8);     
        
        pio_write_8(port + 3, 0x80);    // Enable DLAB (set baud rate divisor)
        
        pio_write_8(port + 0, div_low);    // Set divisor low byte
        pio_write_8(port + 1, div_high);    // Set divisor high byte
        
        pio_write_8(port + 3, pio_read_8(port + 3) & (~0x80));    // Clear DLAB 
        
        return EOK;             
}

static int serial_set_baud_rate(device_t *dev, unsigned int baud_rate) 
{
        serial_dev_data_t *data = (serial_dev_data_t *)dev->driver_data;
        ioport8_t *port = data->port;
        int ret;
        
        fibril_mutex_lock(&data->mutex);        
        serial_port_interrupts_disable(port);    // Disable all interrupts
        ret = serial_port_set_baud_rate(port, baud_rate);
        serial_port_interrupts_enable(port);
        fibril_mutex_unlock(&data->mutex);      
        
        return ret;     
}

static void serial_initialize_port(device_t *dev)
{
        serial_dev_data_t *data = (serial_dev_data_t *)dev->driver_data;
        ioport8_t *port = data->port;
        
        serial_port_interrupts_disable(port);     // Disable all interrupts
        serial_port_set_baud_rate(port, 1200);
        pio_write_8(port + 3, 0x07);    // 8 bits, no parity, two stop bits
        pio_write_8(port + 2, 0xC7);    // Enable FIFO, clear them, with 14-byte threshold
        pio_write_8(port + 4, 0x0B);    // RTS/DSR set (Request to Send and Data Terminal Ready lines enabled), 
                                                                        // Aux Output2 set - needed for interrupts      
}

static void serial_read_from_device(device_t *dev)
{
        serial_dev_data_t *data = (serial_dev_data_t *)dev->driver_data;
        ioport8_t *port = data->port;
        bool cont = true;
        
        while (cont) {  
                fibril_mutex_lock(&data->mutex);
                
                if (cont = serial_received(port)) {
                        uint8_t val = serial_read_8(port);
                        printf(NAME ": character %c read from %s.\n", val, dev->name);
                        
                        
                        if (data->client_connected) {
                                if (!buf_push_back(&(data->input_buffer), val)) {
                                        printf(NAME ": buffer overflow on %s.\n", dev->name);
                                } else {
                                        printf(NAME ": the character %c saved to the buffer of %s.\n", val, dev->name);
                                }
                        } else {
                                printf(NAME ": no client is connected to %s, discarding the character which was read.\n", dev->name);
                        }                       
                }
                
                fibril_mutex_unlock(&data->mutex);      
                
                fibril_yield();         
        }       
}

static inline void serial_interrupt_handler(device_t *dev, ipc_callid_t iid, ipc_call_t *icall)
{
        serial_read_from_device(dev);
}

static inline int serial_register_interrupt_handler(device_t *dev)
{
        serial_dev_data_t *data = (serial_dev_data_t *)dev->driver_data;
        
        return register_interrupt_handler(dev, data->irq, serial_interrupt_handler, NULL);      
}

static inline int serial_unregister_interrupt_handler(device_t *dev)
{
        serial_dev_data_t *data = (serial_dev_data_t *)dev->driver_data;
        
        return unregister_interrupt_handler(dev, data->irq);    
}

static int serial_add_device(device_t *dev) 
{
        printf(NAME ": serial_add_device %s (handle = %d)\n", dev->name, dev->handle);
        
        int res = serial_dev_initialize(dev);
        if (EOK != res) {
                return res;
        }
        
        if (!serial_pio_enable(dev)) {
                serial_dev_cleanup(dev);
                return EADDRNOTAVAIL;
        }       
        
        // find out whether the device is present
        if (!serial_dev_probe(dev)) {
                serial_dev_cleanup(dev);
                return ENOENT;
        }       
        
        // serial port initialization (baud rate etc.)
        serial_initialize_port(dev);
        
        // register interrupt handler
        if (EOK != serial_register_interrupt_handler(dev)) {
                printf(NAME ": failed to register interrupt handler.\n");
                serial_dev_cleanup(dev);
                return res;
        }
        
        // enable interrupt
        if (EOK != (res = serial_interrupt_enable(dev))) {
                printf(NAME ": failed to enable the interrupt. Error code = %d.\n", res);
                serial_dev_cleanup(dev);
                serial_unregister_interrupt_handler(dev);
                return res;
        }       
        
        dev->class = &serial_dev_class;
        
        printf(NAME ": the %s device has been successfully initialized.\n", dev->name);
        
        return EOK;
}

/** Open the device.
 * 
 * This is a callback function called when a client tries to connect to the device.
 * 
 * @param dev the device.
 */
static int serial_open(device_t *dev)
{
        serial_dev_data_t *data = (serial_dev_data_t *)dev->driver_data;
        int res;
        
        fibril_mutex_lock(&data->mutex);        
        
        if (data->client_connected) {
                res = ELIMIT;
        } else {
                res = EOK;
                data->client_connected = true;
        }
        
        fibril_mutex_unlock(&data->mutex);

        return res;
}

/** Close the device.
 * 
 *  This is a callback function called when a client tries to disconnect from the device.
 * 
 * @param dev the device. 
 */
static void serial_close(device_t *dev)
{
        serial_dev_data_t *data = (serial_dev_data_t *)dev->driver_data;
        
        fibril_mutex_lock(&data->mutex);
        
        assert(data->client_connected); 
        
        data->client_connected = false;
        buf_clear(&data->input_buffer);
        
        fibril_mutex_unlock(&data->mutex);       
}

/** Default handler for client requests which are not handled by the standard interfaces.
 * 
 * Configure the parameters of the serial communication.
 */
static void serial_default_handler(device_t *dev, ipc_callid_t callid, ipc_call_t *call)
{
        ipcarg_t method = IPC_GET_METHOD(*call);
        int ret;
        
        switch(method) {
                case SERIAL_SET_BAUD_RATE:
                        ret = serial_set_baud_rate(dev, IPC_GET_ARG1(*call));
                        ipc_answer_0(callid, ret);
                        break;
                case SERIAL_SET_PARITY:
                        // TODO
                        break;
                case SERIAL_SET_STOP_BITS:
                        // TODO
                        break;
                default:
                        ipc_answer_0(callid, ENOTSUP);          
        }
}

/** Initialize the serial port driver.
 * 
 * Initialize class structures with callback methods for handling 
 * client requests to the serial port devices.
 */
static void serial_init() 
{
        // TODO
        serial_dev_class.id = 0;
        serial_dev_class.open = &serial_open;
        serial_dev_class.close = &serial_close; 
        
        serial_dev_class.interfaces[CHAR_DEV_IFACE] = &serial_char_iface;
        serial_dev_class.default_handler = &serial_default_handler;
}

int main(int argc, char *argv[])
{
        printf(NAME ": HelenOS serial port driver\n");  
        serial_init();
        return driver_main(&serial_driver);
}

/**
 * @}
 */