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/**
* @file
*
* @ingroup RTEMSBSPsARMLPC32XX
*
* @brief High speed UART driver (14-clock).
*/
/*
* Copyright (c) 2010-2014 embedded brains GmbH. All rights reserved.
*
* embedded brains GmbH
* Dornierstr. 4
* 82178 Puchheim
* Germany
* <rtems@embedded-brains.de>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#include <bsp.h>
#include <bsp/lpc32xx.h>
#include <bsp/irq.h>
#include <bsp/hsu.h>
#define HSU_FIFO_SIZE 64
#define HSU_LEVEL_RX_MASK 0xffU
#define HSU_LEVEL_TX_MASK 0xff00U
#define HSU_LEVEL_TX_SHIFT 8
#define HSU_RX_DATA_MASK 0xffU
#define HSU_RX_EMPTY (1U << 8)
#define HSU_RX_ERROR (1U << 9)
#define HSU_RX_BREAK (1U << 10)
#define HSU_IIR_TX (1U << 0)
#define HSU_IIR_RX_TRIG (1U << 1)
#define HSU_IIR_RX_TIMEOUT (1U << 2)
#define HSU_CTRL_INTR_DISABLED 0x1280fU
#define HSU_CTRL_RX_INTR_ENABLED 0x1284fU
#define HSU_CTRL_RX_AND_TX_INTR_ENABLED 0x1286fU
/* We are interested in RX timeout, RX trigger and TX trigger interrupts */
#define HSU_IIR_MASK 0x7U
bool lpc32xx_hsu_probe(rtems_termios_device_context *base)
{
lpc32xx_hsu_context *ctx = (lpc32xx_hsu_context *) base;
volatile lpc32xx_hsu *hsu = ctx->hsu;
hsu->ctrl = HSU_CTRL_INTR_DISABLED;
/* Drain FIFOs */
while (hsu->level != 0) {
hsu->fifo;
}
return true;
}
static void lpc32xx_hsu_interrupt_handler(void *arg)
{
rtems_termios_tty *tty = arg;
lpc32xx_hsu_context *ctx = rtems_termios_get_device_context(tty);
volatile lpc32xx_hsu *hsu = ctx->hsu;
/* Iterate until no more interrupts are pending */
do {
int rv = 0;
int i = 0;
char buf [HSU_FIFO_SIZE];
/* Enqueue received characters */
while (i < HSU_FIFO_SIZE) {
uint32_t in = hsu->fifo;
if ((in & HSU_RX_EMPTY) == 0) {
if ((in & HSU_RX_BREAK) == 0) {
buf [i] = in & HSU_RX_DATA_MASK;
++i;
}
} else {
break;
}
}
rtems_termios_enqueue_raw_characters(tty, buf, i);
/* Dequeue transmitted characters */
rv = rtems_termios_dequeue_characters(tty, (int) ctx->chars_in_transmission);
if (rv == 0) {
/* Nothing to transmit */
}
} while ((hsu->iir & HSU_IIR_MASK) != 0);
}
static bool lpc32xx_hsu_first_open(
struct rtems_termios_tty *tty,
rtems_termios_device_context *base,
struct termios *term,
rtems_libio_open_close_args_t *args
)
{
lpc32xx_hsu_context *ctx = (lpc32xx_hsu_context *) base;
volatile lpc32xx_hsu *hsu = ctx->hsu;
rtems_status_code sc;
bool ok;
sc = rtems_interrupt_handler_install(
ctx->irq,
"HSU",
RTEMS_INTERRUPT_UNIQUE,
lpc32xx_hsu_interrupt_handler,
tty
);
ok = sc == RTEMS_SUCCESSFUL;
if (ok) {
rtems_termios_set_initial_baud(tty, ctx->initial_baud);
hsu->ctrl = HSU_CTRL_RX_INTR_ENABLED;
}
return ok;
}
static void lpc32xx_hsu_last_close(
struct rtems_termios_tty *tty,
rtems_termios_device_context *base,
rtems_libio_open_close_args_t *args
)
{
lpc32xx_hsu_context *ctx = (lpc32xx_hsu_context *) base;
volatile lpc32xx_hsu *hsu = ctx->hsu;
hsu->ctrl = HSU_CTRL_INTR_DISABLED;
rtems_interrupt_handler_remove(
ctx->irq,
lpc32xx_hsu_interrupt_handler,
tty
);
}
static void lpc32xx_hsu_write(
rtems_termios_device_context *base,
const char *buf,
size_t len
)
{
lpc32xx_hsu_context *ctx = (lpc32xx_hsu_context *) base;
volatile lpc32xx_hsu *hsu = ctx->hsu;
size_t tx_level = (hsu->level & HSU_LEVEL_TX_MASK) >> HSU_LEVEL_TX_SHIFT;
size_t tx_free = HSU_FIFO_SIZE - tx_level;
size_t i = 0;
size_t out = len > tx_free ? tx_free : len;
for (i = 0; i < out; ++i) {
hsu->fifo = buf [i];
}
ctx->chars_in_transmission = out;
if (len > 0) {
hsu->ctrl = HSU_CTRL_RX_AND_TX_INTR_ENABLED;
} else {
hsu->ctrl = HSU_CTRL_RX_INTR_ENABLED;
hsu->iir = HSU_IIR_TX;
}
}
static bool lpc32xx_hsu_set_attributes(
rtems_termios_device_context *base,
const struct termios *term
)
{
lpc32xx_hsu_context *ctx = (lpc32xx_hsu_context *) base;
volatile lpc32xx_hsu *hsu = ctx->hsu;
int baud_flags = term->c_ospeed;
if (baud_flags != 0) {
int32_t baud = rtems_termios_baud_to_number(baud_flags);
if (baud > 0) {
uint32_t baud_divisor = 14 * (uint32_t) baud;
uint32_t rate = LPC32XX_PERIPH_CLK / baud_divisor;
uint32_t remainder = LPC32XX_PERIPH_CLK - rate * baud_divisor;
if (2 * remainder >= baud_divisor) {
++rate;
}
hsu->rate = rate - 1;
}
}
return true;
}
const rtems_termios_device_handler lpc32xx_hsu_fns = {
.first_open = lpc32xx_hsu_first_open,
.last_close = lpc32xx_hsu_last_close,
.write = lpc32xx_hsu_write,
.set_attributes = lpc32xx_hsu_set_attributes,
.mode = TERMIOS_IRQ_DRIVEN
};
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