| /* |
| * 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); |
| } |
| |