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504 lines
12 KiB
504 lines
12 KiB
// 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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|
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/* Supports: |
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* Timberdale FPGA UART |
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*/ |
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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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|
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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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spin_unlock(&port->lock); |
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tty_flip_buffer_push(tport); |
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spin_lock(&port->lock); |
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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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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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