contiki/cpu/cc26xx/dev/cc26xx-uart.c

385 lines
12 KiB
C

/*
* Copyright (c) 2014, Texas Instruments Incorporated - http://www.ti.com/
* All rights reserved.
*
* 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 of the copyright holder 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 HOLDER 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.
*/
#include "contiki-conf.h"
#include "cc26xx-uart.h"
#include "hw_types.h"
#include "hw_memmap.h"
#include "sys_ctrl.h"
#include "prcm.h"
#include "ioc.h"
#include "uart.h"
#include "lpm.h"
#include "ti-lib.h"
#include "sys/energest.h"
#include <stdint.h>
#include <stdbool.h>
/*---------------------------------------------------------------------------*/
/* Which events to trigger a UART interrupt */
#define CC26XX_UART_RX_INTERRUPT_TRIGGERS (UART_INT_RX | UART_INT_RT)
/* All interrupt masks */
#define CC26XX_UART_INTERRUPT_ALL (UART_INT_OE | UART_INT_BE | UART_INT_PE | \
UART_INT_FE | UART_INT_RT | UART_INT_TX | \
UART_INT_RX | UART_INT_CTS)
/*---------------------------------------------------------------------------*/
#define cc26xx_uart_isr UART0IntHandler
/*---------------------------------------------------------------------------*/
static int (*input_handler)(unsigned char c);
/*---------------------------------------------------------------------------*/
static bool
usable(void)
{
if(BOARD_IOID_UART_RX == IOID_UNUSED ||
BOARD_IOID_UART_TX == IOID_UNUSED ||
CC26XX_UART_CONF_ENABLE == 0) {
return false;
}
return true;
}
/*---------------------------------------------------------------------------*/
static void
power_and_clock(void)
{
/* Power on the SERIAL PD */
ti_lib_prcm_power_domain_on(PRCM_DOMAIN_SERIAL);
while(ti_lib_prcm_power_domain_status(PRCM_DOMAIN_SERIAL)
!= PRCM_DOMAIN_POWER_ON);
/* Enable UART clock in active mode */
ti_lib_prcm_peripheral_run_enable(PRCM_PERIPH_UART0);
ti_lib_prcm_load_set();
while(!ti_lib_prcm_load_get());
}
/*---------------------------------------------------------------------------*/
/*
* Returns 0 if either the SERIAL PD is off, or the PD is on but the run mode
* clock is gated. If this function would return 0, accessing UART registers
* will return a precise bus fault. If this function returns 1, it is safe to
* access UART registers.
*
* This function only checks the 'run mode' clock gate, since it can only ever
* be called with the MCU in run mode.
*/
static bool
accessible(void)
{
/* First, check the PD */
if(ti_lib_prcm_power_domain_status(PRCM_DOMAIN_SERIAL)
!= PRCM_DOMAIN_POWER_ON) {
return false;
}
/* Then check the 'run mode' clock gate */
if(!(HWREG(PRCM_BASE + PRCM_O_UARTCLKGR) & PRCM_UARTCLKGR_CLK_EN)) {
return false;
}
return true;
}
/*---------------------------------------------------------------------------*/
static void
disable_interrupts(void)
{
/* Acknowledge UART interrupts */
ti_lib_int_disable(INT_UART0);
/* Disable all UART module interrupts */
ti_lib_uart_int_disable(UART0_BASE, CC26XX_UART_INTERRUPT_ALL);
/* Clear all UART interrupts */
ti_lib_uart_int_clear(UART0_BASE, CC26XX_UART_INTERRUPT_ALL);
}
/*---------------------------------------------------------------------------*/
static void
enable_interrupts(void)
{
/* Clear all UART interrupts */
ti_lib_uart_int_clear(UART0_BASE, CC26XX_UART_INTERRUPT_ALL);
/* Enable RX-related interrupts only if we have an input handler */
if(input_handler) {
/* Configure which interrupts to generate: FIFO level or after RX timeout */
ti_lib_uart_int_enable(UART0_BASE, CC26XX_UART_RX_INTERRUPT_TRIGGERS);
/* Acknowledge UART interrupts */
ti_lib_int_enable(INT_UART0);
}
}
/*---------------------------------------------------------------------------*/
static void
configure(void)
{
uint32_t ctl_val = UART_CTL_UARTEN | UART_CTL_TXE;
/*
* Make sure the TX pin is output / high before assigning it to UART control
* to avoid falling edge glitches
*/
ti_lib_ioc_pin_type_gpio_output(BOARD_IOID_UART_TX);
ti_lib_gpio_pin_write(BOARD_UART_TX, 1);
/*
* Map UART signals to the correct GPIO pins and configure them as
* hardware controlled.
*/
ti_lib_ioc_pin_type_uart(UART0_BASE, BOARD_IOID_UART_RX, BOARD_IOID_UART_TX,
BOARD_IOID_UART_CTS, BOARD_IOID_UART_RTS);
/* Configure the UART for 115,200, 8-N-1 operation. */
ti_lib_uart_config_set_exp_clk(UART0_BASE, ti_lib_sys_ctrl_clock_get(),
CC26XX_UART_CONF_BAUD_RATE,
(UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE |
UART_CONFIG_PAR_NONE));
/*
* Generate an RX interrupt at FIFO 1/2 full.
* We don't really care about the TX interrupt
*/
ti_lib_uart_fifo_level_set(UART0_BASE, UART_FIFO_TX7_8, UART_FIFO_RX4_8);
/* Enable FIFOs */
HWREG(UART0_BASE + UART_O_LCRH) |= UART_LCRH_FEN;
if(input_handler) {
ctl_val += UART_CTL_RXE;
}
/* Enable TX, RX (conditionally), and the UART. */
HWREG(UART0_BASE + UART_O_CTL) = ctl_val;
}
/*---------------------------------------------------------------------------*/
static void
lpm_drop_handler(uint8_t mode)
{
/*
* First, wait for any outstanding TX to complete. If we have an input
* handler, the SERIAL PD will be kept on and the UART module clock will
* be enabled under sleep as well as deep sleep. In theory, this means that
* we shouldn't lose any outgoing bytes, but we actually do on occasion.
* This byte loss may (or may not) be related to the freezing of IO latches
* between MCU and AON when we drop to deep sleep. This here is essentially a
* workaround
*/
if(accessible() == true) {
while(ti_lib_uart_busy(UART0_BASE));
}
/*
* If we have a registered input_handler then we need to retain RX
* capability. Thus, if this is not a shutdown notification and we have an
* input handler, we do nothing
*/
if((mode != LPM_MODE_SHUTDOWN) && (input_handler != NULL)) {
return;
}
/*
* If we reach here, we either don't care about staying awake or we have
* received a shutdown notification
*
* Only touch UART registers if the module is powered and clocked
*/
if(accessible() == true) {
/* Disable the module */
ti_lib_uart_disable(UART0_BASE);
/* Disable all UART interrupts and clear all flags */
disable_interrupts();
}
/*
* Always stop the clock in run mode. Also stop in Sleep and Deep Sleep if
* this is a request for full shutdown
*/
ti_lib_prcm_peripheral_run_disable(PRCM_PERIPH_UART0);
if(mode == LPM_MODE_SHUTDOWN) {
ti_lib_prcm_peripheral_sleep_disable(PRCM_PERIPH_UART0);
ti_lib_prcm_peripheral_deep_sleep_disable(PRCM_PERIPH_UART0);
}
ti_lib_prcm_load_set();
while(!ti_lib_prcm_load_get());
/* Set pins to low leakage configuration in preparation for deep sleep */
lpm_pin_set_default_state(BOARD_IOID_UART_TX);
lpm_pin_set_default_state(BOARD_IOID_UART_RX);
lpm_pin_set_default_state(BOARD_IOID_UART_CTS);
lpm_pin_set_default_state(BOARD_IOID_UART_RTS);
}
/*---------------------------------------------------------------------------*/
/* Declare a data structure to register with LPM. */
LPM_MODULE(uart_module, NULL, lpm_drop_handler, NULL, LPM_DOMAIN_NONE);
/*---------------------------------------------------------------------------*/
static void
enable(void)
{
power_and_clock();
/* Make sure the peripheral is disabled */
ti_lib_uart_disable(UART0_BASE);
/* Disable all UART interrupts and clear all flags */
disable_interrupts();
/* Setup pins, Baud rate and FIFO levels */
configure();
/* Enable UART interrupts */
enable_interrupts();
}
/*---------------------------------------------------------------------------*/
void
cc26xx_uart_init()
{
bool interrupts_disabled;
/* Return early if disabled by user conf or if ports are misconfigured */
if(usable() == false) {
return;
}
/* Disable Interrupts */
interrupts_disabled = ti_lib_int_master_disable();
/* Register ourselves with the LPM module */
lpm_register_module(&uart_module);
/* Only TX and EN to start with. RX will be enabled only if needed */
input_handler = NULL;
/*
* init() won't actually fire up the UART. We turn it on only when (and if)
* it gets requested, either to enable input or to send out a character
*
* Thus, we simply re-enable processor interrupts here
*/
if(!interrupts_disabled) {
ti_lib_int_master_enable();
}
}
/*---------------------------------------------------------------------------*/
void
cc26xx_uart_write_byte(uint8_t c)
{
/* Return early if disabled by user conf or if ports are misconfigured */
if(usable() == false) {
return;
}
if(accessible() == false) {
enable();
}
ti_lib_uart_char_put(UART0_BASE, c);
}
/*---------------------------------------------------------------------------*/
void
cc26xx_uart_set_input(int (*input)(unsigned char c))
{
input_handler = input;
/* Return early if disabled by user conf or if ports are misconfigured */
if(usable() == false) {
return;
}
if(input == NULL) {
/* Let the SERIAL PD power down */
uart_module.domain_lock = LPM_DOMAIN_NONE;
/* Disable module clocks under sleep and deep sleep */
ti_lib_prcm_peripheral_sleep_disable(PRCM_PERIPH_UART0);
ti_lib_prcm_peripheral_deep_sleep_disable(PRCM_PERIPH_UART0);
} else {
/* Request the SERIAL PD to stay on during deep sleep */
uart_module.domain_lock = LPM_DOMAIN_SERIAL;
/* Enable module clocks under sleep and deep sleep */
ti_lib_prcm_peripheral_sleep_enable(PRCM_PERIPH_UART0);
ti_lib_prcm_peripheral_deep_sleep_enable(PRCM_PERIPH_UART0);
}
ti_lib_prcm_load_set();
while(!ti_lib_prcm_load_get());
enable();
return;
}
/*---------------------------------------------------------------------------*/
uint8_t
cc26xx_uart_busy(void)
{
/* Return early if disabled by user conf or if ports are misconfigured */
if(usable() == false) {
return UART_IDLE;
}
/* If the UART is not accessible, it is not busy */
if(accessible() == false) {
return UART_IDLE;
}
return ti_lib_uart_busy(UART0_BASE);
}
/*---------------------------------------------------------------------------*/
void
cc26xx_uart_isr(void)
{
char the_char;
uint32_t flags;
ENERGEST_ON(ENERGEST_TYPE_IRQ);
power_and_clock();
/* Read out the masked interrupt status */
flags = ti_lib_uart_int_status(UART0_BASE, true);
/* Clear all UART interrupt flags */
ti_lib_uart_int_clear(UART0_BASE, CC26XX_UART_INTERRUPT_ALL);
if((flags & CC26XX_UART_RX_INTERRUPT_TRIGGERS) != 0) {
/*
* If this was a FIFO RX or an RX timeout, read all bytes available in the
* RX FIFO.
*/
while(ti_lib_uart_chars_avail(UART0_BASE)) {
the_char = ti_lib_uart_char_get_non_blocking(UART0_BASE);
if(input_handler != NULL) {
input_handler((unsigned char)the_char);
}
}
}
ENERGEST_OFF(ENERGEST_TYPE_IRQ);
}