| /* |
| * Copyright (c) 2016, The OpenThread Authors. |
| * 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. |
| */ |
| |
| /** |
| * @file |
| * This file implements the OpenThread platform abstraction for UART communication. |
| * |
| */ |
| |
| #include <stddef.h> |
| |
| #include <openthread/types.h> |
| #include <openthread/platform/uart.h> |
| |
| #include "platform-cc2538.h" |
| #include "utils/code_utils.h" |
| |
| enum |
| { |
| kPlatformClock = 32000000, |
| kBaudRate = 115200, |
| kReceiveBufferSize = 128, |
| }; |
| |
| extern void UART0IntHandler(void); |
| |
| static void processReceive(void); |
| static void processTransmit(void); |
| |
| static const uint8_t *sTransmitBuffer = NULL; |
| static uint16_t sTransmitLength = 0; |
| |
| typedef struct RecvBuffer |
| { |
| // The data buffer |
| uint8_t mBuffer[kReceiveBufferSize]; |
| // The offset of the first item written to the list. |
| uint16_t mHead; |
| // The offset of the next item to be written to the list. |
| uint16_t mTail; |
| } RecvBuffer; |
| |
| static RecvBuffer sReceive; |
| |
| otError otPlatUartEnable(void) |
| { |
| uint32_t div; |
| |
| sReceive.mHead = 0; |
| sReceive.mTail = 0; |
| |
| // clock |
| HWREG(SYS_CTRL_RCGCUART) = SYS_CTRL_RCGCUART_UART0; |
| HWREG(SYS_CTRL_SCGCUART) = SYS_CTRL_SCGCUART_UART0; |
| HWREG(SYS_CTRL_DCGCUART) = SYS_CTRL_DCGCUART_UART0; |
| |
| HWREG(UART0_BASE + UART_O_CC) = 0; |
| |
| // tx pin |
| HWREG(IOC_PA1_SEL) = IOC_MUX_OUT_SEL_UART0_TXD; |
| HWREG(IOC_PA1_OVER) = IOC_OVERRIDE_OE; |
| HWREG(GPIO_A_BASE + GPIO_O_AFSEL) |= GPIO_PIN_1; |
| |
| // rx pin |
| HWREG(IOC_PA0_SEL) = IOC_UARTRXD_UART0; |
| HWREG(IOC_PA0_OVER) = IOC_OVERRIDE_DIS; |
| HWREG(GPIO_A_BASE + GPIO_O_AFSEL) |= GPIO_PIN_0; |
| |
| HWREG(UART0_BASE + UART_O_CTL) = 0; |
| |
| // baud rate |
| div = (((kPlatformClock * 8) / kBaudRate) + 1) / 2; |
| HWREG(UART0_BASE + UART_O_IBRD) = div / 64; |
| HWREG(UART0_BASE + UART_O_FBRD) = div % 64; |
| HWREG(UART0_BASE + UART_O_LCRH) = UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE | UART_CONFIG_PAR_NONE; |
| |
| // configure interrupts |
| HWREG(UART0_BASE + UART_O_IM) |= UART_IM_RXIM | UART_IM_RTIM; |
| |
| // enable |
| HWREG(UART0_BASE + UART_O_CTL) = UART_CTL_UARTEN | UART_CTL_TXE | UART_CTL_RXE; |
| |
| // enable interrupts |
| HWREG(NVIC_EN0) = 1 << ((INT_UART0 - 16) & 31); |
| |
| return OT_ERROR_NONE; |
| } |
| |
| otError otPlatUartDisable(void) |
| { |
| return OT_ERROR_NONE; |
| } |
| |
| otError otPlatUartSend(const uint8_t *aBuf, uint16_t aBufLength) |
| { |
| otError error = OT_ERROR_NONE; |
| |
| otEXPECT_ACTION(sTransmitBuffer == NULL, error = OT_ERROR_BUSY); |
| |
| sTransmitBuffer = aBuf; |
| sTransmitLength = aBufLength; |
| |
| exit: |
| return error; |
| } |
| |
| void processReceive(void) |
| { |
| // Copy tail to prevent multiple reads |
| uint16_t tail = sReceive.mTail; |
| |
| // If the data wraps around, process the first part |
| if (sReceive.mHead > tail) |
| { |
| otPlatUartReceived(sReceive.mBuffer + sReceive.mHead, kReceiveBufferSize - sReceive.mHead); |
| |
| // Reset the buffer mHead back to zero. |
| sReceive.mHead = 0; |
| } |
| |
| // For any data remaining, process it |
| if (sReceive.mHead != tail) |
| { |
| otPlatUartReceived(sReceive.mBuffer + sReceive.mHead, tail - sReceive.mHead); |
| |
| // Set mHead to the local tail we have cached |
| sReceive.mHead = tail; |
| } |
| } |
| |
| void processTransmit(void) |
| { |
| otEXPECT(sTransmitBuffer != NULL); |
| |
| for (; sTransmitLength > 0; sTransmitLength--) |
| { |
| while (HWREG(UART0_BASE + UART_O_FR) & UART_FR_TXFF); |
| |
| HWREG(UART0_BASE + UART_O_DR) = *sTransmitBuffer++; |
| } |
| |
| sTransmitBuffer = NULL; |
| otPlatUartSendDone(); |
| |
| exit: |
| return; |
| } |
| |
| void cc2538UartProcess(void) |
| { |
| processReceive(); |
| processTransmit(); |
| } |
| |
| void UART0IntHandler(void) |
| { |
| uint32_t mis; |
| uint8_t byte; |
| |
| mis = HWREG(UART0_BASE + UART_O_MIS); |
| HWREG(UART0_BASE + UART_O_ICR) = mis; |
| |
| if (mis & (UART_IM_RXIM | UART_IM_RTIM)) |
| { |
| while (!(HWREG(UART0_BASE + UART_O_FR) & UART_FR_RXFE)) |
| { |
| byte = HWREG(UART0_BASE + UART_O_DR); |
| |
| // We can only write if incrementing mTail doesn't equal mHead |
| if (sReceive.mHead != (sReceive.mTail + 1) % kReceiveBufferSize) |
| { |
| sReceive.mBuffer[sReceive.mTail] = byte; |
| sReceive.mTail = (sReceive.mTail + 1) % kReceiveBufferSize; |
| } |
| } |
| } |
| } |