--- /dev/null
+/*
+ * timbuart.c timberdale FPGA UART driver
+ * Copyright (c) 2009 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/* Supports:
+ * Timberdale FPGA UART
+ */
+
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+#include <linux/serial_core.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/ioport.h>
+
+#include "timbuart.h"
+
+struct timbuart_port {
+ struct uart_port port;
+ struct tasklet_struct tasklet;
+ int usedma;
+ u8 last_ier;
+ struct platform_device *dev;
+};
+
+static int baudrates[] = {9600, 19200, 38400, 57600, 115200, 230400, 460800,
+ 921600, 1843200, 3250000};
+
+static void timbuart_mctrl_check(struct uart_port *port, u8 isr, u8 *ier);
+
+static irqreturn_t timbuart_handleinterrupt(int irq, void *devid);
+
+static void timbuart_stop_rx(struct uart_port *port)
+{
+ /* spin lock held by upper layer, disable all RX interrupts */
+ u8 ier = ioread8(port->membase + TIMBUART_IER) & ~RXFLAGS;
+ iowrite8(ier, port->membase + TIMBUART_IER);
+}
+
+static void timbuart_stop_tx(struct uart_port *port)
+{
+ /* spinlock held by upper layer, disable TX interrupt */
+ u8 ier = ioread8(port->membase + TIMBUART_IER) & ~TXBAE;
+ iowrite8(ier, port->membase + TIMBUART_IER);
+}
+
+static void timbuart_start_tx(struct uart_port *port)
+{
+ struct timbuart_port *uart =
+ container_of(port, struct timbuart_port, port);
+
+ /* do not transfer anything here -> fire off the tasklet */
+ tasklet_schedule(&uart->tasklet);
+}
+
+static void timbuart_flush_buffer(struct uart_port *port)
+{
+ u8 ctl = ioread8(port->membase + TIMBUART_CTRL) | TIMBUART_CTRL_FLSHTX;
+
+ iowrite8(ctl, port->membase + TIMBUART_CTRL);
+ iowrite8(TXBF, port->membase + TIMBUART_ISR);
+}
+
+static void timbuart_rx_chars(struct uart_port *port)
+{
+ struct tty_struct *tty = port->info->port.tty;
+
+ while (ioread8(port->membase + TIMBUART_ISR) & RXDP) {
+ u8 ch = ioread8(port->membase + TIMBUART_RXFIFO);
+ port->icount.rx++;
+ tty_insert_flip_char(tty, ch, TTY_NORMAL);
+ }
+
+ spin_unlock(&port->lock);
+ tty_flip_buffer_push(port->info->port.tty);
+ spin_lock(&port->lock);
+
+ dev_dbg(port->dev, "%s - total read %d bytes\n",
+ __func__, port->icount.rx);
+}
+
+static void timbuart_tx_chars(struct uart_port *port)
+{
+ struct circ_buf *xmit = &port->info->xmit;
+
+ while (!(ioread8(port->membase + TIMBUART_ISR) & TXBF) &&
+ !uart_circ_empty(xmit)) {
+ iowrite8(xmit->buf[xmit->tail],
+ port->membase + TIMBUART_TXFIFO);
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ port->icount.tx++;
+ }
+
+ dev_dbg(port->dev,
+ "%s - total written %d bytes, CTL: %x, RTS: %x, baud: %x\n",
+ __func__,
+ port->icount.tx,
+ ioread8(port->membase + TIMBUART_CTRL),
+ port->mctrl & TIOCM_RTS,
+ ioread8(port->membase + TIMBUART_BAUDRATE));
+}
+
+static void timbuart_handle_tx_port(struct uart_port *port, u8 isr, u8 *ier)
+{
+ struct timbuart_port *uart =
+ container_of(port, struct timbuart_port, port);
+ struct circ_buf *xmit = &port->info->xmit;
+
+ if (uart_circ_empty(xmit) || uart_tx_stopped(port))
+ return;
+
+ if (port->x_char)
+ return;
+
+ if (isr & TXFLAGS) {
+ timbuart_tx_chars(port);
+ /* clear all TX interrupts */
+ iowrite8(TXFLAGS, port->membase + TIMBUART_ISR);
+
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(port);
+ } else
+ /* Re-enable any tx interrupt */
+ *ier |= uart->last_ier & TXFLAGS;
+
+ /* enable interrupts if there are chars in the transmit buffer,
+ * Or if we delivered some bytes and want the almost empty interrupt
+ * we wake up the upper layer later when we got the interrupt
+ * to give it some time to go out...
+ */
+ if (!uart_circ_empty(xmit))
+ *ier |= TXBAE;
+
+ dev_dbg(port->dev, "%s - leaving\n", __func__);
+}
+
+void timbuart_handle_rx_port(struct uart_port *port, u8 isr, u8 *ier)
+{
+ if (isr & RXFLAGS) {
+ /* Some RX status is set */
+ if (isr & RXBF) {
+ u8 ctl = ioread8(port->membase + TIMBUART_CTRL) |
+ TIMBUART_CTRL_FLSHRX;
+ iowrite8(ctl, port->membase + TIMBUART_CTRL);
+ port->icount.overrun++;
+ } else if (isr & (RXDP))
+ timbuart_rx_chars(port);
+
+ /* ack all RX interrupts */
+ iowrite8(RXFLAGS, port->membase + TIMBUART_ISR);
+ }
+
+ /* always have the RX interrupts enabled */
+ *ier |= RXBAF | RXBF | RXTT;
+
+ dev_dbg(port->dev, "%s - leaving\n", __func__);
+}
+
+void timbuart_tasklet(unsigned long arg)
+{
+ struct timbuart_port *uart = (struct timbuart_port *)arg;
+ u8 isr, ier = 0;
+
+ spin_lock(&uart->port.lock);
+
+ isr = ioread8(uart->port.membase + TIMBUART_ISR);
+ dev_dbg(uart->port.dev, "%s ISR: %x\n", __func__, isr);
+
+ if (!uart->usedma)
+ timbuart_handle_tx_port(&uart->port, isr, &ier);
+
+ timbuart_mctrl_check(&uart->port, isr, &ier);
+
+ if (!uart->usedma)
+ timbuart_handle_rx_port(&uart->port, isr, &ier);
+
+ iowrite8(ier, uart->port.membase + TIMBUART_IER);
+
+ spin_unlock(&uart->port.lock);
+ dev_dbg(uart->port.dev, "%s leaving\n", __func__);
+}
+
+static unsigned int timbuart_tx_empty(struct uart_port *port)
+{
+ u8 isr = ioread8(port->membase + TIMBUART_ISR);
+
+ return (isr & TXBAE) ? TIOCSER_TEMT : 0;
+}
+
+static unsigned int timbuart_get_mctrl(struct uart_port *port)
+{
+ u8 cts = ioread8(port->membase + TIMBUART_CTRL);
+ dev_dbg(port->dev, "%s - cts %x\n", __func__, cts);
+
+ if (cts & TIMBUART_CTRL_CTS)
+ return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
+ else
+ return TIOCM_DSR | TIOCM_CAR;
+}
+
+static void timbuart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+ dev_dbg(port->dev, "%s - %x\n", __func__, mctrl);
+
+ if (mctrl & TIOCM_RTS)
+ iowrite8(TIMBUART_CTRL_RTS, port->membase + TIMBUART_CTRL);
+ else
+ iowrite8(TIMBUART_CTRL_RTS, port->membase + TIMBUART_CTRL);
+}
+
+static void timbuart_mctrl_check(struct uart_port *port, u8 isr, u8 *ier)
+{
+ unsigned int cts;
+
+ if (isr & CTS_DELTA) {
+ /* ack */
+ iowrite8(CTS_DELTA, port->membase + TIMBUART_ISR);
+ cts = timbuart_get_mctrl(port);
+ uart_handle_cts_change(port, cts & TIOCM_CTS);
+ wake_up_interruptible(&port->info->delta_msr_wait);
+ }
+
+ *ier |= CTS_DELTA;
+}
+
+static void timbuart_enable_ms(struct uart_port *port)
+{
+ /* N/A */
+}
+
+static void timbuart_break_ctl(struct uart_port *port, int ctl)
+{
+ /* N/A */
+}
+
+static int timbuart_startup(struct uart_port *port)
+{
+ struct timbuart_port *uart =
+ container_of(port, struct timbuart_port, port);
+
+ dev_dbg(port->dev, "%s\n", __func__);
+
+ iowrite8(TIMBUART_CTRL_FLSHRX, port->membase + TIMBUART_CTRL);
+ iowrite8(0xff, port->membase + TIMBUART_ISR);
+ /* Enable all but TX interrupts */
+ iowrite8(RXBAF | RXBF | RXTT | CTS_DELTA,
+ port->membase + TIMBUART_IER);
+
+ return request_irq(port->irq, timbuart_handleinterrupt, IRQF_SHARED,
+ "timb-uart", uart);
+}
+
+static void timbuart_shutdown(struct uart_port *port)
+{
+ struct timbuart_port *uart =
+ container_of(port, struct timbuart_port, port);
+ dev_dbg(port->dev, "%s\n", __func__);
+ free_irq(port->irq, uart);
+ iowrite8(0, port->membase + TIMBUART_IER);
+}
+
+static int get_bindex(int baud)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(baudrates); i++)
+ if (baud == baudrates[i])
+ return i;
+
+ return -1;
+}
+
+static void timbuart_set_termios(struct uart_port *port,
+ struct ktermios *termios,
+ struct ktermios *old)
+{
+ unsigned int baud;
+ short bindex;
+ unsigned long flags;
+
+ baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
+ bindex = get_bindex(baud);
+ dev_dbg(port->dev, "%s - bindex %d\n", __func__, bindex);
+
+ if (bindex < 0) {
+ printk(KERN_ALERT "timbuart: Unsupported baud rate\n");
+ } else {
+ spin_lock_irqsave(&port->lock, flags);
+ iowrite8((u8)bindex, port->membase + TIMBUART_BAUDRATE);
+ uart_update_timeout(port, termios->c_cflag, baud);
+ spin_unlock_irqrestore(&port->lock, flags);
+ }
+}
+
+static const char *timbuart_type(struct uart_port *port)
+{
+ return port->type == PORT_UNKNOWN ? "timbuart" : NULL;
+}
+
+/* We do not request/release mappings of the registers here,
+ * currently it's done in the proble function.
+ */
+static void timbuart_release_port(struct uart_port *port)
+{
+ struct platform_device *pdev = to_platform_device(port->dev);
+ int size =
+ resource_size(platform_get_resource(pdev, IORESOURCE_MEM, 0));
+
+ if (port->flags & UPF_IOREMAP) {
+ iounmap(port->membase);
+ port->membase = NULL;
+ }
+
+ release_mem_region(port->mapbase, size);
+}
+
+static int timbuart_request_port(struct uart_port *port)
+{
+ struct platform_device *pdev = to_platform_device(port->dev);
+ int size =
+ resource_size(platform_get_resource(pdev, IORESOURCE_MEM, 0));
+
+ if (!request_mem_region(port->mapbase, size, "timb-uart"))
+ return -EBUSY;
+
+ if (port->flags & UPF_IOREMAP) {
+ port->membase = ioremap(port->mapbase, size);
+ if (port->membase == NULL) {
+ release_mem_region(port->mapbase, size);
+ return -ENOMEM;
+ }
+ }
+
+ return 0;
+}
+
+static irqreturn_t timbuart_handleinterrupt(int irq, void *devid)
+{
+ struct timbuart_port *uart = (struct timbuart_port *)devid;
+
+ if (ioread8(uart->port.membase + TIMBUART_IPR)) {
+ uart->last_ier = ioread8(uart->port.membase + TIMBUART_IER);
+
+ /* disable interrupts, the tasklet enables them again */
+ iowrite8(0, uart->port.membase + TIMBUART_IER);
+
+ /* fire off bottom half */
+ tasklet_schedule(&uart->tasklet);
+
+ return IRQ_HANDLED;
+ } else
+ return IRQ_NONE;
+}
+
+/*
+ * Configure/autoconfigure the port.
+ */
+static void timbuart_config_port(struct uart_port *port, int flags)
+{
+ if (flags & UART_CONFIG_TYPE) {
+ port->type = PORT_TIMBUART;
+ timbuart_request_port(port);
+ }
+}
+
+static int timbuart_verify_port(struct uart_port *port,
+ struct serial_struct *ser)
+{
+ /* we don't want the core code to modify any port params */
+ return -EINVAL;
+}
+
+static struct uart_ops timbuart_ops = {
+ .tx_empty = timbuart_tx_empty,
+ .set_mctrl = timbuart_set_mctrl,
+ .get_mctrl = timbuart_get_mctrl,
+ .stop_tx = timbuart_stop_tx,
+ .start_tx = timbuart_start_tx,
+ .flush_buffer = timbuart_flush_buffer,
+ .stop_rx = timbuart_stop_rx,
+ .enable_ms = timbuart_enable_ms,
+ .break_ctl = timbuart_break_ctl,
+ .startup = timbuart_startup,
+ .shutdown = timbuart_shutdown,
+ .set_termios = timbuart_set_termios,
+ .type = timbuart_type,
+ .release_port = timbuart_release_port,
+ .request_port = timbuart_request_port,
+ .config_port = timbuart_config_port,
+ .verify_port = timbuart_verify_port
+};
+
+static struct uart_driver timbuart_driver = {
+ .owner = THIS_MODULE,
+ .driver_name = "timberdale_uart",
+ .dev_name = "ttyTU",
+ .major = TIMBUART_MAJOR,
+ .minor = TIMBUART_MINOR,
+ .nr = 1
+};
+
+static int timbuart_probe(struct platform_device *dev)
+{
+ int err;
+ struct timbuart_port *uart;
+ struct resource *iomem;
+
+ dev_dbg(&dev->dev, "%s\n", __func__);
+
+ uart = kzalloc(sizeof(*uart), GFP_KERNEL);
+ if (!uart) {
+ err = -EINVAL;
+ goto err_mem;
+ }
+
+ uart->usedma = 0;
+
+ uart->port.uartclk = 3250000 * 16;
+ uart->port.fifosize = TIMBUART_FIFO_SIZE;
+ uart->port.regshift = 2;
+ uart->port.iotype = UPIO_MEM;
+ uart->port.ops = &timbuart_ops;
+ uart->port.irq = 0;
+ uart->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP;
+ uart->port.line = 0;
+ uart->port.dev = &dev->dev;
+
+ iomem = platform_get_resource(dev, IORESOURCE_MEM, 0);
+ if (!iomem) {
+ err = -ENOMEM;
+ goto err_register;
+ }
+ uart->port.mapbase = iomem->start;
+ uart->port.membase = NULL;
+
+ uart->port.irq = platform_get_irq(dev, 0);
+ if (uart->port.irq < 0) {
+ err = -EINVAL;
+ goto err_register;
+ }
+
+ tasklet_init(&uart->tasklet, timbuart_tasklet, (unsigned long)uart);
+
+ err = uart_register_driver(&timbuart_driver);
+ if (err)
+ goto err_register;
+
+ err = uart_add_one_port(&timbuart_driver, &uart->port);
+ if (err)
+ goto err_add_port;
+
+ platform_set_drvdata(dev, uart);
+
+ return 0;
+
+err_add_port:
+ uart_unregister_driver(&timbuart_driver);
+err_register:
+ kfree(uart);
+err_mem:
+ printk(KERN_ERR "timberdale: Failed to register Timberdale UART: %d\n",
+ err);
+
+ return err;
+}
+
+static int timbuart_remove(struct platform_device *dev)
+{
+ struct timbuart_port *uart = platform_get_drvdata(dev);
+
+ tasklet_kill(&uart->tasklet);
+ uart_remove_one_port(&timbuart_driver, &uart->port);
+ uart_unregister_driver(&timbuart_driver);
+ kfree(uart);
+
+ return 0;
+}
+
+static struct platform_driver timbuart_platform_driver = {
+ .driver = {
+ .name = "timb-uart",
+ .owner = THIS_MODULE,
+ },
+ .probe = timbuart_probe,
+ .remove = timbuart_remove,
+};
+
+/*--------------------------------------------------------------------------*/
+
+static int __init timbuart_init(void)
+{
+ return platform_driver_register(&timbuart_platform_driver);
+}
+
+static void __exit timbuart_exit(void)
+{
+ platform_driver_unregister(&timbuart_platform_driver);
+}
+
+module_init(timbuart_init);
+module_exit(timbuart_exit);
+
+MODULE_DESCRIPTION("Timberdale UART driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:timb-uart");
+
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff