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https://github.com/Telecominfraproject/OpenCellular.git
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5832b34148
This commit adds initial support for rotor. Basic drivers including: - hardware timer - GPIO - UART - watchdog BUG=chrome-os-partner:51665 BRANCH=None TEST=make -j buildall tests Change-Id: I4e384fc69297f807268dcd43cf47f99ab059fd05 Signed-off-by: Aseda Aboagye <aaboagye@google.com> Reviewed-on: https://chromium-review.googlesource.com/373202 Commit-Ready: Aseda Aboagye <aaboagye@chromium.org> Tested-by: Aseda Aboagye <aaboagye@chromium.org> Reviewed-by: Randall Spangler <rspangler@chromium.org>
139 lines
2.7 KiB
C
139 lines
2.7 KiB
C
/* Copyright 2016 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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/* UART module for Rotor MCU */
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#include "gpio.h"
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#include "registers.h"
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#include "task.h"
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#include "uart.h"
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/* UART reference clock is 200MHz. */
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#define UART_REF_CLK 200000000
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static int init_done;
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void uart_init(void)
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{
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uint16_t divisor;
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/* Ungate the UART clock and the UART reference clock. */
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ROTOR_MCU_UART0_CLKGEN |= (1 << 1);
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ROTOR_MCU_UART0_REFCLKGEN |= (1 << 1);
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/* Set DLAB = 1 */
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ROTOR_MCU_UART_LCR(0) |= (1 << 7);
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/* Set divisor for baud rate. */
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#ifdef BOARD_REI
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divisor = 1;
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#else
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divisor = UART_REF_CLK / (16 * CONFIG_UART_BAUD_RATE);
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#endif /* !defined(BOARD_REI) */
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ROTOR_MCU_UART_DLH(0) = (divisor & 0xFF00) >> 8;
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ROTOR_MCU_UART_DLL(0) = divisor & 0xFF;
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/* Clear DLAB bit. */
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ROTOR_MCU_UART_LCR(0) &= ~(1 << 7);
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/* Set data bits per character to 8. */
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ROTOR_MCU_UART_LCR(0) |= (1 << 1) | (1 << 0);
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/* Enable FIFOs. */
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ROTOR_MCU_UART_FCR(0) |= (1 << 0);
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/* Enable the pins for UART functionality. */
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gpio_config_module(MODULE_UART, 1);
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/* Enable Received Data Available Interrupt. */
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ROTOR_MCU_UART_IER(0) |= (1 << 0);
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/* Enable the interrupt. */
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task_enable_irq(ROTOR_MCU_IRQ_UART_0);
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init_done = 1;
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}
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int uart_init_done(void)
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{
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return init_done;
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}
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void uart_tx_flush(void)
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{
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/* Wait for TX FIFO to empty. */
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while (!(ROTOR_MCU_UART_USR(0) & (1 << 2)))
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;
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}
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int uart_tx_ready(void)
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{
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/* Bit set if TX FIFO is not full. */
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return (ROTOR_MCU_UART_LSR(0) & (1 << 5));
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}
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int uart_tx_in_progress(void)
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{
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/* Bit set if TX FIFO is empty. */
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return !(ROTOR_MCU_UART_USR(0) & (1 << 2));
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}
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int uart_rx_available(void)
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{
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/* Bit set if RX FIFO is not empty. */
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return (ROTOR_MCU_UART_LSR(0) & (1 << 0));
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}
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void uart_write_char(char c)
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{
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/* Wait for space in TX FIFO. */
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while (!uart_tx_ready())
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;
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ROTOR_MCU_UART_THR(0) = c;
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}
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int uart_read_char(void)
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{
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return ROTOR_MCU_UART_RBR(0);
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}
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void uart_disable_interrupt(void)
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{
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task_disable_irq(ROTOR_MCU_IRQ_UART_0);
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}
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void uart_enable_interrupt(void)
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{
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task_enable_irq(ROTOR_MCU_IRQ_UART_0);
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}
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void uart_tx_start(void)
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{
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/* Nothing to do if the interrupt is already enabled. */
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if (ROTOR_MCU_UART_IER(0) & (1 << 1))
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return;
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ROTOR_MCU_UART_IER(0) |= (1 << 1);
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/* Force trigger a UART interrupt. */
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task_trigger_irq(ROTOR_MCU_IRQ_UART_0);
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}
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void uart_tx_stop(void)
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{
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/* Disable Transmit Holding Register Empty interrupt. */
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ROTOR_MCU_UART_IER(0) &= ~(1 << 1);
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}
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void uart_ec_interrupt(void)
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{
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/* Read input FIFO until empty, then fill output FIFO */
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uart_process_input();
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uart_process_output();
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}
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DECLARE_IRQ(ROTOR_MCU_IRQ_UART_0, uart_ec_interrupt, 1);
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