scoutos / prex-0.9.0 / bsp / drv / dev / serial / pl011.c @ 03e9c04a
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/*-
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* Copyright (c) 2008-2009, Kohsuke Ohtani
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* pl011.c - ARM PrimeCell PL011 UART
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*/
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#include <driver.h> |
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#include <tty.h> |
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#include <serial.h> |
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/* #define DEBUG_PL011 1 */
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#ifdef DEBUG_PL011
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#define DPRINTF(a) printf a
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#else
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#define DPRINTF(a)
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#endif
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#define UART_BASE CONFIG_PL011_BASE
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#define UART_IRQ CONFIG_PL011_IRQ
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#define UART_CLK 14745600 |
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#define BAUD_RATE 115200 |
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/* UART Registers */
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#define UART_DR (UART_BASE + 0x00) |
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#define UART_RSR (UART_BASE + 0x04) |
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#define UART_ECR (UART_BASE + 0x04) |
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#define UART_FR (UART_BASE + 0x18) |
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#define UART_IBRD (UART_BASE + 0x24) |
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#define UART_FBRD (UART_BASE + 0x28) |
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#define UART_LCRH (UART_BASE + 0x2c) |
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#define UART_CR (UART_BASE + 0x30) |
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#define UART_IMSC (UART_BASE + 0x38) |
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#define UART_MIS (UART_BASE + 0x40) |
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#define UART_ICR (UART_BASE + 0x44) |
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/* Flag register */
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#define FR_RXFE 0x10 /* Receive FIFO empty */ |
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#define FR_TXFF 0x20 /* Transmit FIFO full */ |
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/* Masked interrupt status register */
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#define MIS_RX 0x10 /* Receive interrupt */ |
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#define MIS_TX 0x20 /* Transmit interrupt */ |
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/* Interrupt clear register */
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#define ICR_RX 0x10 /* Clear receive interrupt */ |
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#define ICR_TX 0x20 /* Clear transmit interrupt */ |
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/* Line control register (High) */
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#define LCRH_WLEN8 0x60 /* 8 bits */ |
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#define LCRH_FEN 0x10 /* Enable FIFO */ |
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/* Control register */
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#define CR_UARTEN 0x0001 /* UART enable */ |
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#define CR_TXE 0x0100 /* Transmit enable */ |
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#define CR_RXE 0x0200 /* Receive enable */ |
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/* Interrupt mask set/clear register */
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#define IMSC_RX 0x10 /* Receive interrupt mask */ |
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#define IMSC_TX 0x20 /* Transmit interrupt mask */ |
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/* Forward functions */
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static int pl011_init(struct driver *); |
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static void pl011_xmt_char(struct serial_port *, char); |
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static char pl011_rcv_char(struct serial_port *); |
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static void pl011_set_poll(struct serial_port *, int); |
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static void pl011_start(struct serial_port *); |
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static void pl011_stop(struct serial_port *); |
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struct driver pl011_driver = {
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/* name */ "pl011", |
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/* devops */ NULL, |
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/* devsz */ 0, |
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/* flags */ 0, |
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/* probe */ NULL, |
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/* init */ pl011_init,
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/* detach */ NULL, |
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}; |
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static struct serial_ops pl011_ops = { |
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/* xmt_char */ pl011_xmt_char,
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/* rcv_char */ pl011_rcv_char,
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/* set_poll */ pl011_set_poll,
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/* start */ pl011_start,
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/* stop */ pl011_stop,
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}; |
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static struct serial_port pl011_port; |
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static void |
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pl011_xmt_char(struct serial_port *sp, char c) |
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{ |
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while (bus_read_32(UART_FR) & FR_TXFF)
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; |
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bus_write_32(UART_DR, (uint32_t)c); |
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} |
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static char |
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pl011_rcv_char(struct serial_port *sp)
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{ |
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char c;
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while (bus_read_32(UART_FR) & FR_RXFE)
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; |
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c = bus_read_32(UART_DR) & 0xff;
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return c;
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} |
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static void |
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pl011_set_poll(struct serial_port *sp, int on) |
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{ |
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if (on) {
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/*
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* Disable interrupt for polling mode.
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*/
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bus_write_32(UART_IMSC, 0);
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} else
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bus_write_32(UART_IMSC, (IMSC_RX | IMSC_TX)); |
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} |
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static int |
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pl011_isr(void *arg)
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{ |
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struct serial_port *sp = arg;
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int c;
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uint32_t mis; |
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mis = bus_read_32(UART_MIS); |
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if (mis & MIS_RX) {
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/*
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* Receive interrupt
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*/
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while (bus_read_32(UART_FR) & FR_RXFE)
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; |
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do {
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c = bus_read_32(UART_DR); |
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serial_rcv_char(sp, c); |
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} while ((bus_read_32(UART_FR) & FR_RXFE) == 0); |
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/* Clear interrupt status */
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bus_write_32(UART_ICR, ICR_RX); |
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} |
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if (mis & MIS_TX) {
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/*
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* Transmit interrupt
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*/
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serial_xmt_done(sp); |
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/* Clear interrupt status */
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bus_write_32(UART_ICR, ICR_TX); |
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} |
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return 0; |
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} |
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static void |
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pl011_start(struct serial_port *sp)
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{ |
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uint32_t divider, remainder, fraction; |
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bus_write_32(UART_CR, 0); /* Disable everything */ |
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bus_write_32(UART_ICR, 0x07ff); /* Clear all interrupt status */ |
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/*
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* Set baud rate:
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* IBRD = UART_CLK / (16 * BAUD_RATE)
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* FBRD = ROUND((64 * MOD(UART_CLK,(16 * BAUD_RATE))) / (16 * BAUD_RATE))
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*/
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divider = UART_CLK / (16 * BAUD_RATE);
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remainder = UART_CLK % (16 * BAUD_RATE);
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fraction = (8 * remainder / BAUD_RATE) >> 1; |
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fraction += (8 * remainder / BAUD_RATE) & 1; |
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bus_write_32(UART_IBRD, divider); |
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bus_write_32(UART_FBRD, fraction); |
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/* Set N, 8, 1, FIFO enable */
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bus_write_32(UART_LCRH, (LCRH_WLEN8 | LCRH_FEN)); |
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/* Enable UART */
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bus_write_32(UART_CR, (CR_RXE | CR_TXE | CR_UARTEN)); |
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/* Install interrupt handler */
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sp->irq = irq_attach(UART_IRQ, IPL_COMM, 0, pl011_isr, IST_NONE, sp);
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/* Enable TX/RX interrupt */
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bus_write_32(UART_IMSC, (IMSC_RX | IMSC_TX)); |
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} |
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static void |
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pl011_stop(struct serial_port *sp)
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{ |
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bus_write_32(UART_IMSC, 0); /* Disable all interrupts */ |
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bus_write_32(UART_CR, 0); /* Disable everything */ |
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} |
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static int |
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pl011_init(struct driver *self)
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{ |
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serial_attach(&pl011_ops, &pl011_port); |
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return 0; |
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} |