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/*
* Copyright (c) 2012 Corey Tabaka
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge,
* publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <dev/driver.h>
#include <dev/class/uart.h>
#include <debug.h>
#include <assert.h>
#include <malloc.h>
#include <err.h>
#include <lib/cbuf.h>
#include <platform/uart.h>
#include <arch/x86.h>
#include <kernel/thread.h>
#include <platform/interrupts.h>
struct device_class uart_device_class = {
.name = "uart",
};
struct uart_driver_state {
struct cbuf rx_buf;
struct cbuf tx_buf;
};
static status_t uart_init(struct device *dev);
static enum handler_return uart_irq_handler(void *arg);
static int uart_write_thread(void *arg);
static ssize_t uart_read(struct device *dev, void *buf, size_t len);
static ssize_t uart_write(struct device *dev, const void *buf, size_t len);
static struct uart_ops the_ops = {
.std = {
.device_class = &uart_device_class,
.init = uart_init,
},
.read = uart_read,
.write = uart_write,
};
DRIVER_EXPORT(uart, &the_ops.std);
static status_t uart_init(struct device *dev)
{
status_t res = NO_ERROR;
if (!dev)
return ERR_INVALID_ARGS;
if (!dev->config)
return ERR_NOT_CONFIGURED;
const struct platform_uart_config *config = dev->config;
struct uart_driver_state *state = malloc(sizeof(struct uart_driver_state));
if (!state) {
res = ERR_NO_MEMORY;
goto done;
}
dev->state = state;
/* set up the driver state */
cbuf_initialize(&state->rx_buf, config->rx_buf_len);
cbuf_initialize(&state->tx_buf, config->tx_buf_len);
/* configure the uart */
int divisor = 115200 / config->baud_rate;
outp(config->io_port + 3, 0x80); // set up to load divisor latch
outp(config->io_port + 0, divisor & 0xff); // lsb
outp(config->io_port + 1, divisor >> 8); // msb
outp(config->io_port + 3, 3); // 8N1
outp(config->io_port + 2, 0x07); // enable FIFO, clear, 14-byte threshold
register_int_handler(config->irq, uart_irq_handler, dev);
unmask_interrupt(config->irq);
//outp(config->io_port + 1, 0x3); // enable rx data available and tx holding empty interrupts
outp(config->io_port + 1, 0x1); // enable rx data available interrupts
thread_resume(thread_create("[uart writer]", uart_write_thread, dev, DEFAULT_PRIORITY,
DEFAULT_STACK_SIZE));
done:
return res;
}
static enum handler_return uart_irq_handler(void *arg)
{
bool resched = false;
struct device *dev = arg;
DEBUG_ASSERT(dev);
DEBUG_ASSERT(dev->config);
DEBUG_ASSERT(dev->state);
const struct platform_uart_config *config = dev->config;
struct uart_driver_state *state = dev->state;
while (inp(config->io_port + 5) & (1<<0)) {
char c = inp(config->io_port + 0);
cbuf_write(&state->rx_buf, &c, 1, false);
resched = true;
}
return resched ? INT_RESCHEDULE : INT_NO_RESCHEDULE;
}
static int uart_write_thread(void *arg)
{
struct device *dev = arg;
DEBUG_ASSERT(dev);
DEBUG_ASSERT(dev->config);
DEBUG_ASSERT(dev->state);
const struct platform_uart_config *config = dev->config;
struct uart_driver_state *state = dev->state;
return 0;
while (true) {
char c = cbuf_read(&state->tx_buf, &c, 1, true);
while ((inp(config->io_port + 5) & (1<<6)) == 0)
;
outp(config->io_port + 0, c);
}
return 0;
}
static ssize_t uart_read(struct device *dev, void *buf, size_t len)
{
if (!dev || !buf)
return ERR_INVALID_ARGS;
DEBUG_ASSERT(dev->state);
struct uart_driver_state *state = dev->state;
return cbuf_read(&state->rx_buf, buf, len, true);
}
static ssize_t uart_write(struct device *dev, const void *buf, size_t len)
{
if (!dev || !buf)
return ERR_INVALID_ARGS;
DEBUG_ASSERT(dev->state);
struct uart_driver_state *state = dev->state;
return cbuf_write(&state->tx_buf, buf, len, true);
}
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