serial_lld.c
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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011,2012 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
---
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes ChibiOS/RT, without being obliged to provide
the source code for any proprietary components. See the file exception.txt
for full details of how and when the exception can be applied.
*/
/**
* @file LPC11xx/serial_lld.c
* @brief LPC11xx low level serial driver code.
*
* @addtogroup SERIAL
* @{
*/
#include "ch.h"
#include "hal.h"
#if HAL_USE_SERIAL || defined(__DOXYGEN__)
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
#if LPC11xx_SERIAL_USE_UART0 || defined(__DOXYGEN__)
/** @brief UART0 serial driver identifier.*/
SerialDriver SD1;
#endif
/*===========================================================================*/
/* Driver local variables. */
/*===========================================================================*/
/** @brief Driver default configuration.*/
static const SerialConfig default_config = {
SERIAL_DEFAULT_BITRATE,
LCR_WL8 | LCR_STOP1 | LCR_NOPARITY,
FCR_TRIGGER0
};
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
/**
* @brief UART initialization.
*
* @param[in] sdp communication channel associated to the UART
* @param[in] config the architecture-dependent serial driver configuration
*/
static void uart_init(SerialDriver *sdp, const SerialConfig *config) {
LPC_UART_TypeDef *u = sdp->uart;
uint32_t div = LPC11xx_SERIAL_UART0_PCLK / (config->sc_speed << 4);
u->LCR = config->sc_lcr | LCR_DLAB;
u->DLL = div;
u->DLM = div >> 8;
u->LCR = config->sc_lcr;
u->FCR = FCR_ENABLE | FCR_RXRESET | FCR_TXRESET | config->sc_fcr;
u->ACR = 0;
u->FDR = 0x10;
u->TER = TER_ENABLE;
u->IER = IER_RBR | IER_STATUS;
}
/**
* @brief UART de-initialization.
*
* @param[in] u pointer to an UART I/O block
*/
static void uart_deinit(LPC_UART_TypeDef *u) {
u->LCR = LCR_DLAB;
u->DLL = 1;
u->DLM = 0;
u->LCR = 0;
u->FDR = 0x10;
u->IER = 0;
u->FCR = FCR_RXRESET | FCR_TXRESET;
u->ACR = 0;
u->TER = TER_ENABLE;
}
/**
* @brief Error handling routine.
*
* @param[in] sdp communication channel associated to the UART
* @param[in] err UART LSR register value
*/
static void set_error(SerialDriver *sdp, IOREG32 err) {
ioflags_t sts = 0;
if (err & LSR_OVERRUN)
sts |= SD_OVERRUN_ERROR;
if (err & LSR_PARITY)
sts |= SD_PARITY_ERROR;
if (err & LSR_FRAMING)
sts |= SD_FRAMING_ERROR;
if (err & LSR_BREAK)
sts |= SD_BREAK_DETECTED;
chSysLockFromIsr();
chIOAddFlagsI(sdp, sts);
chSysUnlockFromIsr();
}
/**
* @brief Common IRQ handler.
* @note Tries hard to clear all the pending interrupt sources, we don't
* want to go through the whole ISR and have another interrupt soon
* after.
*
* @param[in] u pointer to an UART I/O block
* @param[in] sdp communication channel associated to the UART
*/
static void serve_interrupt(SerialDriver *sdp) {
LPC_UART_TypeDef *u = sdp->uart;
while (TRUE) {
switch (u->IIR & IIR_SRC_MASK) {
case IIR_SRC_NONE:
return;
case IIR_SRC_ERROR:
set_error(sdp, u->LSR);
break;
case IIR_SRC_TIMEOUT:
case IIR_SRC_RX:
chSysLockFromIsr();
if (chIQIsEmptyI(&sdp->iqueue))
chIOAddFlagsI(sdp, IO_INPUT_AVAILABLE);
chSysUnlockFromIsr();
while (u->LSR & LSR_RBR_FULL) {
chSysLockFromIsr();
if (chIQPutI(&sdp->iqueue, u->RBR) < Q_OK)
chIOAddFlagsI(sdp, SD_OVERRUN_ERROR);
chSysUnlockFromIsr();
}
break;
case IIR_SRC_TX:
{
int i = LPC11xx_SERIAL_FIFO_PRELOAD;
do {
msg_t b;
chSysLockFromIsr();
b = chOQGetI(&sdp->oqueue);
chSysUnlockFromIsr();
if (b < Q_OK) {
u->IER &= ~IER_THRE;
chSysLockFromIsr();
chIOAddFlagsI(sdp, IO_OUTPUT_EMPTY);
chSysUnlockFromIsr();
break;
}
u->THR = b;
} while (--i);
}
break;
default:
(void) u->THR;
(void) u->RBR;
}
}
}
/**
* @brief Attempts a TX FIFO preload.
*/
static void preload(SerialDriver *sdp) {
LPC_UART_TypeDef *u = sdp->uart;
if (u->LSR & LSR_THRE) {
int i = LPC11xx_SERIAL_FIFO_PRELOAD;
do {
msg_t b = chOQGetI(&sdp->oqueue);
if (b < Q_OK) {
chIOAddFlagsI(sdp, IO_OUTPUT_EMPTY);
return;
}
u->THR = b;
} while (--i);
}
u->IER |= IER_THRE;
}
/**
* @brief Driver SD1 output notification.
*/
#if LPC11xx_SERIAL_USE_UART0 || defined(__DOXYGEN__)
static void notify1(GenericQueue *qp) {
(void)qp;
preload(&SD1);
}
#endif
/*===========================================================================*/
/* Driver interrupt handlers. */
/*===========================================================================*/
/**
* @brief UART0 IRQ handler.
*
* @isr
*/
#if LPC11xx_SERIAL_USE_UART0 || defined(__DOXYGEN__)
CH_IRQ_HANDLER(Vector94) {
CH_IRQ_PROLOGUE();
serve_interrupt(&SD1);
CH_IRQ_EPILOGUE();
}
#endif
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/**
* @brief Low level serial driver initialization.
*
* @notapi
*/
void sd_lld_init(void) {
#if LPC11xx_SERIAL_USE_UART0
sdObjectInit(&SD1, NULL, notify1);
SD1.uart = LPC_UART;
LPC_IOCON->PIO1_6 = 0xC1; /* RDX without resistors. */
LPC_IOCON->PIO1_7 = 0xC1; /* TDX without resistors. */
#endif
}
/**
* @brief Low level serial driver configuration and (re)start.
*
* @param[in] sdp pointer to a @p SerialDriver object
* @param[in] config the architecture-dependent serial driver configuration.
* If this parameter is set to @p NULL then a default
* configuration is used.
*
* @notapi
*/
void sd_lld_start(SerialDriver *sdp, const SerialConfig *config) {
if (config == NULL)
config = &default_config;
if (sdp->state == SD_STOP) {
#if LPC11xx_SERIAL_USE_UART0
if (&SD1 == sdp) {
LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 12);
LPC_SYSCON->UARTCLKDIV = LPC11xx_SERIAL_UART0CLKDIV;
nvicEnableVector(UART_IRQn,
CORTEX_PRIORITY_MASK(LPC11xx_SERIAL_UART0_IRQ_PRIORITY));
}
#endif
}
uart_init(sdp, config);
}
/**
* @brief Low level serial driver stop.
* @details De-initializes the UART, stops the associated clock, resets the
* interrupt vector.
*
* @param[in] sdp pointer to a @p SerialDriver object
*
* @notapi
*/
void sd_lld_stop(SerialDriver *sdp) {
if (sdp->state == SD_READY) {
uart_deinit(sdp->uart);
#if LPC11xx_SERIAL_USE_UART0
if (&SD1 == sdp) {
LPC_SYSCON->UARTCLKDIV = 0;
LPC_SYSCON->SYSAHBCLKCTRL &= ~(1 << 12);
nvicDisableVector(UART_IRQn);
return;
}
#endif
}
}
#endif /* HAL_USE_SERIAL */
/** @} */