503 lines
12 KiB
C
503 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* timbuart.c timberdale FPGA UART driver
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* Copyright (c) 2009 Intel Corporation
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*/
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/* Supports:
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* Timberdale FPGA UART
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*/
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#include <linux/pci.h>
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#include <linux/interrupt.h>
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#include <linux/serial_core.h>
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#include <linux/tty.h>
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#include <linux/tty_flip.h>
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#include <linux/ioport.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include "timbuart.h"
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struct timbuart_port {
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struct uart_port port;
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struct tasklet_struct tasklet;
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int usedma;
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u32 last_ier;
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struct platform_device *dev;
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};
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static int baudrates[] = {9600, 19200, 38400, 57600, 115200, 230400, 460800,
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921600, 1843200, 3250000};
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static void timbuart_mctrl_check(struct uart_port *port, u32 isr, u32 *ier);
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static irqreturn_t timbuart_handleinterrupt(int irq, void *devid);
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static void timbuart_stop_rx(struct uart_port *port)
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{
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/* spin lock held by upper layer, disable all RX interrupts */
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u32 ier = ioread32(port->membase + TIMBUART_IER) & ~RXFLAGS;
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iowrite32(ier, port->membase + TIMBUART_IER);
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}
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static void timbuart_stop_tx(struct uart_port *port)
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{
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/* spinlock held by upper layer, disable TX interrupt */
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u32 ier = ioread32(port->membase + TIMBUART_IER) & ~TXBAE;
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iowrite32(ier, port->membase + TIMBUART_IER);
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}
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static void timbuart_start_tx(struct uart_port *port)
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{
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struct timbuart_port *uart =
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container_of(port, struct timbuart_port, port);
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/* do not transfer anything here -> fire off the tasklet */
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tasklet_schedule(&uart->tasklet);
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}
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static unsigned int timbuart_tx_empty(struct uart_port *port)
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{
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u32 isr = ioread32(port->membase + TIMBUART_ISR);
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return (isr & TXBE) ? TIOCSER_TEMT : 0;
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}
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static void timbuart_flush_buffer(struct uart_port *port)
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{
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if (!timbuart_tx_empty(port)) {
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u8 ctl = ioread8(port->membase + TIMBUART_CTRL) |
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TIMBUART_CTRL_FLSHTX;
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iowrite8(ctl, port->membase + TIMBUART_CTRL);
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iowrite32(TXBF, port->membase + TIMBUART_ISR);
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}
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}
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static void timbuart_rx_chars(struct uart_port *port)
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{
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struct tty_port *tport = &port->state->port;
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while (ioread32(port->membase + TIMBUART_ISR) & RXDP) {
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u8 ch = ioread8(port->membase + TIMBUART_RXFIFO);
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port->icount.rx++;
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tty_insert_flip_char(tport, ch, TTY_NORMAL);
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}
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tty_flip_buffer_push(tport);
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dev_dbg(port->dev, "%s - total read %d bytes\n",
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__func__, port->icount.rx);
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}
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static void timbuart_tx_chars(struct uart_port *port)
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{
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struct circ_buf *xmit = &port->state->xmit;
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while (!(ioread32(port->membase + TIMBUART_ISR) & TXBF) &&
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!uart_circ_empty(xmit)) {
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iowrite8(xmit->buf[xmit->tail],
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port->membase + TIMBUART_TXFIFO);
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xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
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port->icount.tx++;
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}
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dev_dbg(port->dev,
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"%s - total written %d bytes, CTL: %x, RTS: %x, baud: %x\n",
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__func__,
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port->icount.tx,
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ioread8(port->membase + TIMBUART_CTRL),
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port->mctrl & TIOCM_RTS,
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ioread8(port->membase + TIMBUART_BAUDRATE));
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}
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static void timbuart_handle_tx_port(struct uart_port *port, u32 isr, u32 *ier)
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{
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struct timbuart_port *uart =
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container_of(port, struct timbuart_port, port);
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struct circ_buf *xmit = &port->state->xmit;
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if (uart_circ_empty(xmit) || uart_tx_stopped(port))
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return;
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if (port->x_char)
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return;
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if (isr & TXFLAGS) {
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timbuart_tx_chars(port);
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/* clear all TX interrupts */
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iowrite32(TXFLAGS, port->membase + TIMBUART_ISR);
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if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
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uart_write_wakeup(port);
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} else
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/* Re-enable any tx interrupt */
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*ier |= uart->last_ier & TXFLAGS;
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/* enable interrupts if there are chars in the transmit buffer,
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* Or if we delivered some bytes and want the almost empty interrupt
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* we wake up the upper layer later when we got the interrupt
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* to give it some time to go out...
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*/
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if (!uart_circ_empty(xmit))
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*ier |= TXBAE;
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dev_dbg(port->dev, "%s - leaving\n", __func__);
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}
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static void timbuart_handle_rx_port(struct uart_port *port, u32 isr, u32 *ier)
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{
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if (isr & RXFLAGS) {
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/* Some RX status is set */
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if (isr & RXBF) {
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u8 ctl = ioread8(port->membase + TIMBUART_CTRL) |
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TIMBUART_CTRL_FLSHRX;
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iowrite8(ctl, port->membase + TIMBUART_CTRL);
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port->icount.overrun++;
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} else if (isr & (RXDP))
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timbuart_rx_chars(port);
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/* ack all RX interrupts */
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iowrite32(RXFLAGS, port->membase + TIMBUART_ISR);
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}
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/* always have the RX interrupts enabled */
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*ier |= RXBAF | RXBF | RXTT;
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dev_dbg(port->dev, "%s - leaving\n", __func__);
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}
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static void timbuart_tasklet(struct tasklet_struct *t)
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{
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struct timbuart_port *uart = from_tasklet(uart, t, tasklet);
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u32 isr, ier = 0;
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spin_lock(&uart->port.lock);
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isr = ioread32(uart->port.membase + TIMBUART_ISR);
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dev_dbg(uart->port.dev, "%s ISR: %x\n", __func__, isr);
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if (!uart->usedma)
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timbuart_handle_tx_port(&uart->port, isr, &ier);
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timbuart_mctrl_check(&uart->port, isr, &ier);
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if (!uart->usedma)
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timbuart_handle_rx_port(&uart->port, isr, &ier);
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iowrite32(ier, uart->port.membase + TIMBUART_IER);
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spin_unlock(&uart->port.lock);
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dev_dbg(uart->port.dev, "%s leaving\n", __func__);
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}
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static unsigned int timbuart_get_mctrl(struct uart_port *port)
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{
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u8 cts = ioread8(port->membase + TIMBUART_CTRL);
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dev_dbg(port->dev, "%s - cts %x\n", __func__, cts);
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if (cts & TIMBUART_CTRL_CTS)
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return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
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else
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return TIOCM_DSR | TIOCM_CAR;
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}
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static void timbuart_set_mctrl(struct uart_port *port, unsigned int mctrl)
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{
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dev_dbg(port->dev, "%s - %x\n", __func__, mctrl);
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if (mctrl & TIOCM_RTS)
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iowrite8(TIMBUART_CTRL_RTS, port->membase + TIMBUART_CTRL);
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else
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iowrite8(0, port->membase + TIMBUART_CTRL);
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}
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static void timbuart_mctrl_check(struct uart_port *port, u32 isr, u32 *ier)
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{
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unsigned int cts;
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if (isr & CTS_DELTA) {
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/* ack */
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iowrite32(CTS_DELTA, port->membase + TIMBUART_ISR);
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cts = timbuart_get_mctrl(port);
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uart_handle_cts_change(port, cts & TIOCM_CTS);
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wake_up_interruptible(&port->state->port.delta_msr_wait);
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}
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*ier |= CTS_DELTA;
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}
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static void timbuart_break_ctl(struct uart_port *port, int ctl)
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{
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/* N/A */
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}
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static int timbuart_startup(struct uart_port *port)
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{
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struct timbuart_port *uart =
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container_of(port, struct timbuart_port, port);
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dev_dbg(port->dev, "%s\n", __func__);
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iowrite8(TIMBUART_CTRL_FLSHRX, port->membase + TIMBUART_CTRL);
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iowrite32(0x1ff, port->membase + TIMBUART_ISR);
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/* Enable all but TX interrupts */
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iowrite32(RXBAF | RXBF | RXTT | CTS_DELTA,
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port->membase + TIMBUART_IER);
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return request_irq(port->irq, timbuart_handleinterrupt, IRQF_SHARED,
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"timb-uart", uart);
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}
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static void timbuart_shutdown(struct uart_port *port)
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{
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struct timbuart_port *uart =
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container_of(port, struct timbuart_port, port);
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dev_dbg(port->dev, "%s\n", __func__);
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free_irq(port->irq, uart);
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iowrite32(0, port->membase + TIMBUART_IER);
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timbuart_flush_buffer(port);
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}
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static int get_bindex(int baud)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(baudrates); i++)
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if (baud <= baudrates[i])
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return i;
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return -1;
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}
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static void timbuart_set_termios(struct uart_port *port,
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struct ktermios *termios,
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const struct ktermios *old)
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{
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unsigned int baud;
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short bindex;
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unsigned long flags;
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baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
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bindex = get_bindex(baud);
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dev_dbg(port->dev, "%s - bindex %d\n", __func__, bindex);
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if (bindex < 0)
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bindex = 0;
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baud = baudrates[bindex];
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/* The serial layer calls into this once with old = NULL when setting
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up initially */
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if (old)
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tty_termios_copy_hw(termios, old);
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tty_termios_encode_baud_rate(termios, baud, baud);
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spin_lock_irqsave(&port->lock, flags);
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iowrite8((u8)bindex, port->membase + TIMBUART_BAUDRATE);
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uart_update_timeout(port, termios->c_cflag, baud);
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spin_unlock_irqrestore(&port->lock, flags);
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}
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static const char *timbuart_type(struct uart_port *port)
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{
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return port->type == PORT_UNKNOWN ? "timbuart" : NULL;
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}
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/* We do not request/release mappings of the registers here,
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* currently it's done in the proble function.
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*/
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static void timbuart_release_port(struct uart_port *port)
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{
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struct platform_device *pdev = to_platform_device(port->dev);
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int size =
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resource_size(platform_get_resource(pdev, IORESOURCE_MEM, 0));
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if (port->flags & UPF_IOREMAP) {
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iounmap(port->membase);
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port->membase = NULL;
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}
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release_mem_region(port->mapbase, size);
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}
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static int timbuart_request_port(struct uart_port *port)
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{
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struct platform_device *pdev = to_platform_device(port->dev);
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int size =
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resource_size(platform_get_resource(pdev, IORESOURCE_MEM, 0));
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if (!request_mem_region(port->mapbase, size, "timb-uart"))
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return -EBUSY;
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if (port->flags & UPF_IOREMAP) {
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port->membase = ioremap(port->mapbase, size);
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if (port->membase == NULL) {
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release_mem_region(port->mapbase, size);
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return -ENOMEM;
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}
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}
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return 0;
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}
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static irqreturn_t timbuart_handleinterrupt(int irq, void *devid)
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{
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struct timbuart_port *uart = (struct timbuart_port *)devid;
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if (ioread8(uart->port.membase + TIMBUART_IPR)) {
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uart->last_ier = ioread32(uart->port.membase + TIMBUART_IER);
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/* disable interrupts, the tasklet enables them again */
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iowrite32(0, uart->port.membase + TIMBUART_IER);
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/* fire off bottom half */
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tasklet_schedule(&uart->tasklet);
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return IRQ_HANDLED;
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} else
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return IRQ_NONE;
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}
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/*
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* Configure/autoconfigure the port.
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*/
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static void timbuart_config_port(struct uart_port *port, int flags)
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{
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if (flags & UART_CONFIG_TYPE) {
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port->type = PORT_TIMBUART;
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timbuart_request_port(port);
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}
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}
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static int timbuart_verify_port(struct uart_port *port,
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struct serial_struct *ser)
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{
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/* we don't want the core code to modify any port params */
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return -EINVAL;
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}
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static const struct uart_ops timbuart_ops = {
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.tx_empty = timbuart_tx_empty,
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.set_mctrl = timbuart_set_mctrl,
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.get_mctrl = timbuart_get_mctrl,
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.stop_tx = timbuart_stop_tx,
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.start_tx = timbuart_start_tx,
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.flush_buffer = timbuart_flush_buffer,
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.stop_rx = timbuart_stop_rx,
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.break_ctl = timbuart_break_ctl,
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.startup = timbuart_startup,
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.shutdown = timbuart_shutdown,
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.set_termios = timbuart_set_termios,
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.type = timbuart_type,
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.release_port = timbuart_release_port,
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.request_port = timbuart_request_port,
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.config_port = timbuart_config_port,
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.verify_port = timbuart_verify_port
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};
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static struct uart_driver timbuart_driver = {
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.owner = THIS_MODULE,
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.driver_name = "timberdale_uart",
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.dev_name = "ttyTU",
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.major = TIMBUART_MAJOR,
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.minor = TIMBUART_MINOR,
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.nr = 1
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};
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static int timbuart_probe(struct platform_device *dev)
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{
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int err, irq;
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struct timbuart_port *uart;
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struct resource *iomem;
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dev_dbg(&dev->dev, "%s\n", __func__);
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uart = kzalloc(sizeof(*uart), GFP_KERNEL);
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if (!uart) {
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err = -EINVAL;
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goto err_mem;
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}
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uart->usedma = 0;
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uart->port.uartclk = 3250000 * 16;
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uart->port.fifosize = TIMBUART_FIFO_SIZE;
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uart->port.regshift = 2;
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uart->port.iotype = UPIO_MEM;
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uart->port.ops = &timbuart_ops;
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uart->port.irq = 0;
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uart->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP;
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uart->port.line = 0;
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uart->port.dev = &dev->dev;
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iomem = platform_get_resource(dev, IORESOURCE_MEM, 0);
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if (!iomem) {
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err = -ENOMEM;
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goto err_register;
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}
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uart->port.mapbase = iomem->start;
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uart->port.membase = NULL;
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irq = platform_get_irq(dev, 0);
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if (irq < 0) {
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err = -EINVAL;
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goto err_register;
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}
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uart->port.irq = irq;
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tasklet_setup(&uart->tasklet, timbuart_tasklet);
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err = uart_register_driver(&timbuart_driver);
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if (err)
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goto err_register;
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err = uart_add_one_port(&timbuart_driver, &uart->port);
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if (err)
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goto err_add_port;
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platform_set_drvdata(dev, uart);
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return 0;
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err_add_port:
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uart_unregister_driver(&timbuart_driver);
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err_register:
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kfree(uart);
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err_mem:
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printk(KERN_ERR "timberdale: Failed to register Timberdale UART: %d\n",
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err);
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return err;
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}
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static int timbuart_remove(struct platform_device *dev)
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{
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struct timbuart_port *uart = platform_get_drvdata(dev);
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tasklet_kill(&uart->tasklet);
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uart_remove_one_port(&timbuart_driver, &uart->port);
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uart_unregister_driver(&timbuart_driver);
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kfree(uart);
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return 0;
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}
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static struct platform_driver timbuart_platform_driver = {
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.driver = {
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.name = "timb-uart",
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},
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.probe = timbuart_probe,
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.remove = timbuart_remove,
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};
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module_platform_driver(timbuart_platform_driver);
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MODULE_DESCRIPTION("Timberdale UART driver");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:timb-uart");
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