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nuttx/arch/arm/src/lpc43xx/lpc43_uart.c

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/**************************************************************************
* arch/arm/src/lpc43xx/lpc43_uart.c
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*
**************************************************************************/
/**************************************************************************
* Included Files
**************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <arch/irq.h>
#include <arch/board/board.h>
#include "up_internal.h"
#include "up_arch.h"
#include "chip.h"
#include "lpc43_config.h"
#include "lpc43_pinconfig.h"
#include "lpc43_rgu.h"
#include "lpc43_cgu.h"
#include "lpc43_uart.h"
/**************************************************************************
* Pre-processor Definitions
**************************************************************************/
/* Select UART parameters for the selected console */
#if defined(CONFIG_USART0_SERIAL_CONSOLE)
# define CONSOLE_BASE LPC43_USART0_BASE
# define CONSOLE_BASEFREQ BOARD_USART0_BASEFREQ
# define CONSOLE_BAUD CONFIG_USART0_BAUD
# define CONSOLE_BITS CONFIG_USART0_BITS
# define CONSOLE_PARITY CONFIG_USART0_PARITY
# define CONSOLE_2STOP CONFIG_USART0_2STOP
#elif defined(CONFIG_UART1_SERIAL_CONSOLE)
# define CONSOLE_BASE LPC43_UART1_BASE
# define CONSOLE_BASEFREQ BOARD_UART1_BASEFREQ
# define CONSOLE_BAUD CONFIG_UART1_BAUD
# define CONSOLE_BITS CONFIG_UART1_BITS
# define CONSOLE_PARITY CONFIG_UART1_PARITY
# define CONSOLE_2STOP CONFIG_UART1_2STOP
#elif defined(CONFIG_USART2_SERIAL_CONSOLE)
# define CONSOLE_BASE LPC43_USART2_BASE
# define CONSOLE_BASEFREQ BOARD_USART2_BASEFREQ
# define CONSOLE_BAUD CONFIG_USART2_BAUD
# define CONSOLE_BITS CONFIG_USART2_BITS
# define CONSOLE_PARITY CONFIG_USART2_PARITY
# define CONSOLE_2STOP CONFIG_USART2_2STOP
#elif defined(CONFIG_USART3_SERIAL_CONSOLE)
# define CONSOLE_BASE LPC43_USART3_BASE
# define CONSOLE_BASEFREQ BOARD_USART3_BASEFREQ
# define CONSOLE_BAUD CONFIG_USART3_BAUD
# define CONSOLE_BITS CONFIG_USART3_BITS
# define CONSOLE_PARITY CONFIG_USART3_PARITY
# define CONSOLE_2STOP CONFIG_USART3_2STOP
#elif defined(HAVE_CONSOLE)
# error "No CONFIG_UARTn_SERIAL_CONSOLE Setting"
#endif
/* Get word length setting for the console */
#if CONSOLE_BITS == 5
# define CONSOLE_LCR_WLS UART_LCR_WLS_5BIT
#elif CONSOLE_BITS == 6
# define CONSOLE_LCR_WLS UART_LCR_WLS_6BIT
#elif CONSOLE_BITS == 7
# define CONSOLE_LCR_WLS UART_LCR_WLS_7BIT
#elif CONSOLE_BITS == 8
# define CONSOLE_LCR_WLS UART_LCR_WLS_8BIT
#elif defined(HAVE_CONSOLE)
# error "Invalid CONFIG_UARTn_BITS setting for console "
#endif
/* Get parity setting for the console */
#if CONSOLE_PARITY == 0
# define CONSOLE_LCR_PAR 0
#elif CONSOLE_PARITY == 1
# define CONSOLE_LCR_PAR (UART_LCR_PE|UART_LCR_PS_ODD)
#elif CONSOLE_PARITY == 2
# define CONSOLE_LCR_PAR (UART_LCR_PE|UART_LCR_PS_EVEN)
#elif CONSOLE_PARITY == 3
# define CONSOLE_LCR_PAR (UART_LCR_PE|UART_LCR_PS_STICK1)
#elif CONSOLE_PARITY == 4
# define CONSOLE_LCR_PAR (UART_LCR_PE|UART_LCR_PS_STICK0)
#elif defined(HAVE_CONSOLE)
# error "Invalid CONFIG_UARTn_PARITY setting for CONSOLE"
#endif
/* Get stop-bit setting for the console and USART0/2/3, UART1 */
#if CONSOLE_2STOP != 0
# define CONSOLE_LCR_STOP UART_LCR_STOP
#else
# define CONSOLE_LCR_STOP 0
#endif
/* LCR and FCR values for the console */
#define CONSOLE_LCR_VALUE (CONSOLE_LCR_WLS | CONSOLE_LCR_PAR | \
CONSOLE_LCR_STOP)
#define CONSOLE_FCR_VALUE (UART_FCR_RXTRIGGER_8 | UART_FCR_TXRST |\
UART_FCR_RXRST | UART_FCR_FIFOEN)
/**************************************************************************
* Private Types
**************************************************************************/
/**************************************************************************
* Private Function Prototypes
**************************************************************************/
/**************************************************************************
* Global Variables
**************************************************************************/
/**************************************************************************
* Private Variables
**************************************************************************/
/**************************************************************************
* Private Functions
**************************************************************************/
/**************************************************************************
* Public Functions
**************************************************************************/
/**************************************************************************
* Name: up_lowputc
*
* Description:
* Output one byte on the serial console
*
**************************************************************************/
void up_lowputc(char ch)
{
#if defined HAVE_UART && defined HAVE_CONSOLE
/* Wait for the transmitter to be available */
while ((getreg32(CONSOLE_BASE+LPC43_UART_LSR_OFFSET) & UART_LSR_THRE) == 0);
/* Send the character */
putreg32((uint32_t)ch, CONSOLE_BASE+LPC43_UART_THR_OFFSET);
#endif
}
/**************************************************************************
* Name: lpc43_lowsetup
*
* Description:
* This performs basic initialization of the UART used for the serial
* console. Its purpose is to get the console output availabe as soon
* as possible.
*
* The USART0/2/3 and UART1 peripherals are configured using the following registers:
* 1. Baud rate: In the LCR register, set bit DLAB = 1. This enables access
* to registers DLL and DLM for setting the baud rate. Also, if needed,
* set the fractional baud rate in the fractional divider
* 2. UART FIFO: Use bit FIFO enable (bit 0) in FCR register to
* enable FIFO.
* 3. Pins: Select UART pins through the PINSEL registers and pin modes
* through the PINMODE registers. UART receive pins should not have
* pull-down resistors enabled.
* 4. Interrupts: To enable UART interrupts set bit DLAB = 0 in the LCRF
* register. This enables access to IER. Interrupts are enabled
* in the NVIC using the appropriate Interrupt Set Enable register.
* 5. DMA: UART transmit and receive functions can operate with the
* GPDMA controller.
*
**************************************************************************/
void lpc43_lowsetup(void)
{
#ifdef HAVE_UART
/* Enable clocking and for all console UART and disable power for
* other UARTs
*/
#if defined(CONFIG_USART0_SERIAL_CONSOLE)
lpc43_usart0_setup();
#elif defined(CONFIG_UART1_SERIAL_CONSOLE)
lpc43_uart1_setup();
#elif defined(CONFIG_USART2_SERIAL_CONSOLE)
lpc43_usart2_setup();
#elif defined(CONFIG_USART3_SERIAL_CONSOLE)
lpc43_usart3_setup();
#endif
/* Configure the console (only) */
#if defined(HAVE_CONSOLE) && !defined(CONFIG_SUPPRESS_UART_CONFIG)
/* Clear fifos */
putreg32(UART_FCR_RXRST|UART_FCR_TXRST, CONSOLE_BASE+LPC43_UART_FCR_OFFSET);
/* Set trigger */
putreg32(UART_FCR_FIFOEN|UART_FCR_RXTRIGGER_8, CONSOLE_BASE+LPC43_UART_FCR_OFFSET);
/* Set up the LCR */
putreg32(CONSOLE_LCR_VALUE, CONSOLE_BASE+LPC43_UART_LCR_OFFSET);
/* Set the BAUD divisor */
lpc43_setbaud(CONSOLE_BASE, CONSOLE_BASEFREQ, CONSOLE_BAUD);
/* Configure the FIFOs */
putreg32(UART_FCR_RXTRIGGER_8|UART_FCR_TXRST|UART_FCR_RXRST|UART_FCR_FIFOEN,
CONSOLE_BASE+LPC43_UART_FCR_OFFSET);
#endif
#endif /* HAVE_UART */
}
/****************************************************************************
* Name: lpc43_u[s]art0/1/2/3_reset
*
* Description:
* Reset a UART. These functions are used by the serial driver when a
* UART is closed.
*
****************************************************************************/
#ifdef CONFIG_LPC43_USART0
void lpc43_usart0_reset(void)
{
putreg32(RGU_CTRL1_USART0_RST, LPC43_RGU_CTRL1);
}
#endif
#ifdef CONFIG_LPC43_UART1
void lpc43_uart1_reset(void)
{
putreg32(RGU_CTRL1_UART1_RST, LPC43_RGU_CTRL1);
}
#endif
#ifdef CONFIG_LPC43_USART2
void lpc43_usart2_reset(void)
{
putreg32(RGU_CTRL1_USART2_RST, LPC43_RGU_CTRL1);
}
#endif
#ifdef CONFIG_LPC43_USART3
void lpc43_usart3_reset(void)
{
putreg32(RGU_CTRL1_USART3_RST, LPC43_RGU_CTRL1);
}
#endif
/****************************************************************************
* Name: lpc43_usart0_setup, lpc43_uart1_setup, lpc43_usart2_setup, and
* lpc43_usart3_setup
*
* Description:
* Configure the U[S]ART. This involves:
*
* 1. Connecting the input clock to the U[S]ART as specified in the
* board.h file,
* 2. Configuring the U[S]ART pins
*
* USART0/2/3 and UART1 clocking and power control:
*
* ----------------------------------- -------------- --------------
* BASE CLOCK BRANCH CLOCK
* ----------------------------------- -------------- --------------
* USART0 clock to register interface BASE_M4_CLK CLK_M4_USART0
* USART0 peripheral clock (PCLK) BASE_UART0_CLK CLK_APB0_UART0
* UART1 clock to register interface BASE_M4_CLK CLK_M4_UART1
* UART1 peripheral clock (PCLK) BASE_UART1_CLK CLK_APB0_UART1
* USART2 clock to register interface BASE_M4_CLK CLK_M4_USART2
* USART2 peripheral clock (PCLK) BASE_UART2_CLK CLK_APB2_UART2
* USART3 clock to register interface BASE_M4_CLK CLK_M4_USART3
* USART3 peripheral clock (PCLK) BASE_UART3_CLK CLK_APB2_UART3
* ----------------------------------- -------------- --------------
*
****************************************************************************/
#ifdef CONFIG_LPC43_USART0
void lpc43_usart0_setup(void)
{
uint32_t regval;
irqstate_t flags;
/* Connect USART0 into the clock source specified in board.h */
flags = irqsave();
regval = getreg32(LPC43_BASE_USART0_CLK);
regval &= ~BASE_USART0_CLK_CLKSEL_MASK;
regval |= (BOARD_USART0_CLKSRC | BASE_USART0_CLK_AUTOBLOCK);
putreg32(regval, LPC43_BASE_USART0_CLK);
/* Configure I/O pins. NOTE that multiple pin configuration options must
* be disambiguated by defining the pin configuration in the board.h
* header file.
*/
lpc43_pin_config(PINCONF_U0_TXD);
lpc43_pin_config(PINCONF_U0_RXD);
/* If USART RS-485 mode is selected, then configure the DIR pin as well.
* NOTE, again, that multiple pin configuration options must be
* disambiguated by defining the pin configuration in the board.h header
* file.
*/
#ifdef CONFIG_USART0_RS485MODE
lpc43_pin_config(PINCONF_U0_DIR);
#endif
irqrestore(flags);
};
#endif
#ifdef CONFIG_LPC43_UART1
void lpc43_uart1_setup(void)
{
uint32_t regval;
irqstate_t flags;
/* Connect UART1 into the clock source specified in board.h */
flags = irqsave();
regval = getreg32(LPC43_BASE_UART1_CLK);
regval &= ~BASE_UART1_CLK_CLKSEL_MASK;
regval |= (BOARD_UART1_CLKSRC | BASE_UART1_CLK_AUTOBLOCK);
putreg32(regval, LPC43_BASE_UART1_CLK);
/* Configure I/O pins. NOTE that multiple pin configuration options must
* be disambiguated by defining the pin configuration in the board.h
* header file.
*/
lpc43_pin_config(PINCONF_U1_TXD);
lpc43_pin_config(PINCONF_U1_RXD);
#ifdef CONFIG_UART1_FLOWCONTROL
lpc43_pin_config(PINCONF_U1_CTS);
lpc43_pin_config(PINCONF_U1_DCD);
lpc43_pin_config(PINCONF_U1_DSR);
lpc43_pin_config(PINCONF_U1_DTR);
lpc43_pin_config(PINCONF_U1_RTS);
#ifdef CONFIG_UART1_RINGINDICATOR
lpc43_pin_config(PINCONF_U1_RI);
#endif
#endif
irqrestore(flags);
};
#endif
#ifdef CONFIG_LPC43_USART2
void lpc43_usart2_setup(void)
{
uint32_t regval;
irqstate_t flags;
/* Connect USART2 the clock source specified in board.h */
flags = irqsave();
regval = getreg32(LPC43_BASE_USART2_CLK);
regval &= ~BASE_USART2_CLK_CLKSEL_MASK;
regval |= (BOARD_USART2_CLKSRC | BASE_USART2_CLK_AUTOBLOCK);
putreg32(regval, LPC43_BASE_USART2_CLK);
/* Configure I/O pins. NOTE that multiple pin configuration options must
* be disambiguated by defining the pin configuration in the board.h
* header file.
*/
lpc43_pin_config(PINCONF_U2_TXD);
lpc43_pin_config(PINCONF_U2_RXD);
/* If USART RS-485 mode is selected, then configure the DIR pin as well.
* NOTE, again, that multiple pin configuration options must be
* disambiguated by defining the pin configuration in the board.h header
* file.
*/
#ifdef CONFIG_USART2_RS485MODE
lpc43_pin_config(PINCONF_U2_DIR);
#endif
irqrestore(flags);
};
#endif
#ifdef CONFIG_LPC43_USART3
void lpc43_usart3_setup(void)
{
uint32_t regval;
irqstate_t flags;
/* Connect USART3 into the clock source specified in board.h */
flags = irqsave();
regval = getreg32(LPC43_BASE_USART3_CLK);
regval &= ~BASE_USART3_CLK_CLKSEL_MASK;
regval |= (BOARD_USART3_CLKSRC | BASE_USART3_CLK_AUTOBLOCK);
putreg32(regval, LPC43_BASE_USART3_CLK);
/* Configure I/O pins. NOTE that multiple pin configuration options must
* be disambiguated by defining the pin configuration in the board.h
* header file.
*/
lpc43_pin_config(PINCONF_U3_TXD);
lpc43_pin_config(PINCONF_U3_RXD);
/* If USART RS-485 mode is selected, then configure the DIR pin as well.
* NOTE, again, that multiple pin configuration options must be
* disambiguated by defining the pin configuration in the board.h header
* file.
*/
#ifdef CONFIG_USART3_RS485MODE
lpc43_pin_config(PINCONF_U3_DIR);
#endif
irqrestore(flags);
};
#endif
/****************************************************************************
* Name: lpc43_setbaud
*
* Description:
* Configure the U[S]ART divisors to accomplish the desired BAUD given the
* U[S]ART base frequency.
*
* This computationally intensive algorithm is based on the same logic
* used in the NXP sample code.
*
****************************************************************************/
void lpc43_setbaud(uintptr_t uartbase, uint32_t basefreq, uint32_t baud)
{
uint32_t lcr; /* Line control register value */
uint32_t dl; /* Best DLM/DLL full value */
uint32_t mul; /* Best FDR MULVALL value */
uint32_t divadd; /* Best FDR DIVADDVAL value */
uint32_t best; /* Error value associated with best {dl, mul, divadd} */
uint32_t cdl; /* Candidate DLM/DLL full value */
uint32_t cmul; /* Candidate FDR MULVALL value */
uint32_t cdivadd; /* Candidate FDR DIVADDVAL value */
uint32_t errval; /* Error value associated with the candidate */
/* The U[S]ART buad is given by:
*
* Fbaud = Fbase * mul / (mul + divadd) / (16 * dl)
* dl = Fbase * mul / (mul + divadd) / Fbaud / 16
* = Fbase * mul / ((mul + divadd) * Fbaud * 16)
* = ((Fbase * mul) >> 4) / ((mul + divadd) * Fbaud)
*
* Where the value of MULVAL and DIVADDVAL comply with:
*
* 0 < mul < 16
* 0 <= divadd < mul
*/
best = UINT32_MAX;
divadd = 0;
mul = 0;
dl = 0;
/* Try each mulitplier value in the valid range */
for (cmul = 1 ; cmul < 16; cmul++)
{
/* Try each divider value in the valid range */
for (cdivadd = 0 ; cdivadd < cmul ; cdivadd++)
{
/* Candidate:
* dl = ((Fbase * mul) >> 4) / ((mul + cdivadd) * Fbaud)
* (dl << 32) = (Fbase << 28) * cmul / ((mul + cdivadd) * Fbaud)
*/
uint64_t dl64 = ((uint64_t)basefreq << 28) * cmul /
((cmul + cdivadd) * baud);
/* The lower 32-bits of this value is the error */
errval = (uint32_t)(dl64 & 0x00000000ffffffffull);
/* The upper 32-bits is the candidate DL value */
cdl = (uint32_t)(dl64 >> 32);
/* Round up */
if (errval > (1 << 31))
{
errval = -errval;
cdl++;
}
/* Check if the resulting candidate DL value is within range */
if (cdl < 1 || cdl > 65536)
{
/* No... try a different divadd value */
continue;
}
/* Is this the best combination that we have seen so far? */
if (errval < best)
{
/* Yes.. then the candidate is out best guess so far */
best = errval;
dl = cdl;
divadd = cdivadd;
mul = cmul;
/* If the new best guess is exact (within our precision), then
* we are finished.
*/
if (best == 0)
{
break;
}
}
}
}
DEBUGASSERT(dl > 0);
/* Enter DLAB=1 */
lcr = getreg32(uartbase + LPC43_UART_LCR_OFFSET);
putreg32(lcr | UART_LCR_DLAB, uartbase + LPC43_UART_LCR_OFFSET);
/* Save then divider values */
putreg32(dl >> 8, uartbase + LPC43_UART_DLM_OFFSET);
putreg32(dl & 0xff, uartbase + LPC43_UART_DLL_OFFSET);
/* Clear DLAB */
putreg32(lcr & ~UART_LCR_DLAB, uartbase + LPC43_UART_LCR_OFFSET);
/* Then save the fractional divider values */
putreg32((mul << UART_FDR_MULVAL_SHIFT) | (divadd << UART_FDR_DIVADDVAL_SHIFT),
uartbase + LPC43_UART_FDR_OFFSET);
}
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