/* * 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/tty.h> #include <linux/tty_flip.h> #include <linux/kernel.h> #include <linux/platform_device.h> #include <linux/ioport.h> #include <linux/slab.h> #include <linux/module.h> #include "timbuart.h" struct timbuart_port { struct uart_port port; struct tasklet_struct tasklet; int usedma; u32 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, u32 isr, u32 *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 */ u32 ier = ioread32(port->membase + TIMBUART_IER) & ~RXFLAGS; iowrite32(ier, port->membase + TIMBUART_IER); } static void timbuart_stop_tx(struct uart_port *port) { /* spinlock held by upper layer, disable TX interrupt */ u32 ier = ioread32(port->membase + TIMBUART_IER) & ~TXBAE; iowrite32(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 unsigned int timbuart_tx_empty(struct uart_port *port) { u32 isr = ioread32(port->membase + TIMBUART_ISR); return (isr & TXBE) ? TIOCSER_TEMT : 0; } static void timbuart_flush_buffer(struct uart_port *port) { if (!timbuart_tx_empty(port)) { u8 ctl = ioread8(port->membase + TIMBUART_CTRL) | TIMBUART_CTRL_FLSHTX; iowrite8(ctl, port->membase + TIMBUART_CTRL); iowrite32(TXBF, port->membase + TIMBUART_ISR); } } static void timbuart_rx_chars(struct uart_port *port) { struct tty_port *tport = &port->state->port; while (ioread32(port->membase + TIMBUART_ISR) & RXDP) { u8 ch = ioread8(port->membase + TIMBUART_RXFIFO); port->icount.rx++; tty_insert_flip_char(tport, ch, TTY_NORMAL); } spin_unlock(&port->lock); tty_flip_buffer_push(tport); 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->state->xmit; while (!(ioread32(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, u32 isr, u32 *ier) { struct timbuart_port *uart = container_of(port, struct timbuart_port, port); struct circ_buf *xmit = &port->state->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 */ iowrite32(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__); } static void timbuart_handle_rx_port(struct uart_port *port, u32 isr, u32 *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 */ iowrite32(RXFLAGS, port->membase + TIMBUART_ISR); } /* always have the RX interrupts enabled */ *ier |= RXBAF | RXBF | RXTT; dev_dbg(port->dev, "%s - leaving\n", __func__); } static void timbuart_tasklet(unsigned long arg) { struct timbuart_port *uart = (struct timbuart_port *)arg; u32 isr, ier = 0; spin_lock(&uart->port.lock); isr = ioread32(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); iowrite32(ier, uart->port.membase + TIMBUART_IER); spin_unlock(&uart->port.lock); dev_dbg(uart->port.dev, "%s leaving\n", __func__); } 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(0, port->membase + TIMBUART_CTRL); } static void timbuart_mctrl_check(struct uart_port *port, u32 isr, u32 *ier) { unsigned int cts; if (isr & CTS_DELTA) { /* ack */ iowrite32(CTS_DELTA, port->membase + TIMBUART_ISR); cts = timbuart_get_mctrl(port); uart_handle_cts_change(port, cts & TIOCM_CTS); wake_up_interruptible(&port->state->port.delta_msr_wait); } *ier |= CTS_DELTA; } 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); iowrite32(0x1ff, port->membase + TIMBUART_ISR); /* Enable all but TX interrupts */ iowrite32(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); iowrite32(0, port->membase + TIMBUART_IER); timbuart_flush_buffer(port); } 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) bindex = 0; baud = baudrates[bindex]; /* The serial layer calls into this once with old = NULL when setting up initially */ if (old) tty_termios_copy_hw(termios, old); tty_termios_encode_baud_rate(termios, baud, baud); 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 = ioread32(uart->port.membase + TIMBUART_IER); /* disable interrupts, the tasklet enables them again */ iowrite32(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, .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, irq; 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; irq = platform_get_irq(dev, 0); if (irq < 0) { err = -EINVAL; goto err_register; } uart->port.irq = irq; 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", }, .probe = timbuart_probe, .remove = timbuart_remove, }; module_platform_driver(timbuart_platform_driver); MODULE_DESCRIPTION("Timberdale UART driver"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:timb-uart");