diff options
Diffstat (limited to 'drivers/serial/vt8500_serial.c')
| -rw-r--r-- | drivers/serial/vt8500_serial.c | 648 |
1 files changed, 648 insertions, 0 deletions
diff --git a/drivers/serial/vt8500_serial.c b/drivers/serial/vt8500_serial.c new file mode 100644 index 00000000000..322bf56c0d8 --- /dev/null +++ b/drivers/serial/vt8500_serial.c @@ -0,0 +1,648 @@ +/* + * drivers/serial/vt8500_serial.c + * + * Copyright (C) 2010 Alexey Charkov <alchark@gmail.com> + * + * Based on msm_serial.c, which is: + * Copyright (C) 2007 Google, Inc. + * Author: Robert Love <rlove@google.com> + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * 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. + */ + +#if defined(CONFIG_SERIAL_VT8500_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) +# define SUPPORT_SYSRQ +#endif + +#include <linux/hrtimer.h> +#include <linux/delay.h> +#include <linux/module.h> +#include <linux/io.h> +#include <linux/ioport.h> +#include <linux/irq.h> +#include <linux/init.h> +#include <linux/console.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/serial_core.h> +#include <linux/serial.h> +#include <linux/slab.h> +#include <linux/clk.h> +#include <linux/platform_device.h> + +/* + * UART Register offsets + */ + +#define VT8500_URTDR 0x0000 /* Transmit data */ +#define VT8500_URRDR 0x0004 /* Receive data */ +#define VT8500_URDIV 0x0008 /* Clock/Baud rate divisor */ +#define VT8500_URLCR 0x000C /* Line control */ +#define VT8500_URICR 0x0010 /* IrDA control */ +#define VT8500_URIER 0x0014 /* Interrupt enable */ +#define VT8500_URISR 0x0018 /* Interrupt status */ +#define VT8500_URUSR 0x001c /* UART status */ +#define VT8500_URFCR 0x0020 /* FIFO control */ +#define VT8500_URFIDX 0x0024 /* FIFO index */ +#define VT8500_URBKR 0x0028 /* Break signal count */ +#define VT8500_URTOD 0x002c /* Time out divisor */ +#define VT8500_TXFIFO 0x1000 /* Transmit FIFO (16x8) */ +#define VT8500_RXFIFO 0x1020 /* Receive FIFO (16x10) */ + +/* + * Interrupt enable and status bits + */ + +#define TXDE (1 << 0) /* Tx Data empty */ +#define RXDF (1 << 1) /* Rx Data full */ +#define TXFAE (1 << 2) /* Tx FIFO almost empty */ +#define TXFE (1 << 3) /* Tx FIFO empty */ +#define RXFAF (1 << 4) /* Rx FIFO almost full */ +#define RXFF (1 << 5) /* Rx FIFO full */ +#define TXUDR (1 << 6) /* Tx underrun */ +#define RXOVER (1 << 7) /* Rx overrun */ +#define PER (1 << 8) /* Parity error */ +#define FER (1 << 9) /* Frame error */ +#define TCTS (1 << 10) /* Toggle of CTS */ +#define RXTOUT (1 << 11) /* Rx timeout */ +#define BKDONE (1 << 12) /* Break signal done */ +#define ERR (1 << 13) /* AHB error response */ + +#define RX_FIFO_INTS (RXFAF | RXFF | RXOVER | PER | FER | RXTOUT) +#define TX_FIFO_INTS (TXFAE | TXFE | TXUDR) + +struct vt8500_port { + struct uart_port uart; + char name[16]; + struct clk *clk; + unsigned int ier; +}; + +static inline void vt8500_write(struct uart_port *port, unsigned int val, + unsigned int off) +{ + writel(val, port->membase + off); +} + +static inline unsigned int vt8500_read(struct uart_port *port, unsigned int off) +{ + return readl(port->membase + off); +} + +static void vt8500_stop_tx(struct uart_port *port) +{ + struct vt8500_port *vt8500_port = container_of(port, + struct vt8500_port, + uart); + + vt8500_port->ier &= ~TX_FIFO_INTS; + vt8500_write(port, vt8500_port->ier, VT8500_URIER); +} + +static void vt8500_stop_rx(struct uart_port *port) +{ + struct vt8500_port *vt8500_port = container_of(port, + struct vt8500_port, + uart); + + vt8500_port->ier &= ~RX_FIFO_INTS; + vt8500_write(port, vt8500_port->ier, VT8500_URIER); +} + +static void vt8500_enable_ms(struct uart_port *port) +{ + struct vt8500_port *vt8500_port = container_of(port, + struct vt8500_port, + uart); + + vt8500_port->ier |= TCTS; + vt8500_write(port, vt8500_port->ier, VT8500_URIER); +} + +static void handle_rx(struct uart_port *port) +{ + struct tty_struct *tty = tty_port_tty_get(&port->state->port); + if (!tty) { + /* Discard data: no tty available */ + int count = (vt8500_read(port, VT8500_URFIDX) & 0x1f00) >> 8; + u16 ch; + while (count--) + ch = readw(port->membase + VT8500_RXFIFO); + return; + } + + /* + * Handle overrun + */ + if ((vt8500_read(port, VT8500_URISR) & RXOVER)) { + port->icount.overrun++; + tty_insert_flip_char(tty, 0, TTY_OVERRUN); + } + + /* and now the main RX loop */ + while (vt8500_read(port, VT8500_URFIDX) & 0x1f00) { + unsigned int c; + char flag = TTY_NORMAL; + + c = readw(port->membase + VT8500_RXFIFO) & 0x3ff; + + /* Mask conditions we're ignorning. */ + c &= ~port->read_status_mask; + + if (c & FER) { + port->icount.frame++; + flag = TTY_FRAME; + } else if (c & PER) { + port->icount.parity++; + flag = TTY_PARITY; + } + port->icount.rx++; + + if (!uart_handle_sysrq_char(port, c)) + tty_insert_flip_char(tty, c, flag); + } + + tty_flip_buffer_push(tty); + tty_kref_put(tty); +} + +static void handle_tx(struct uart_port *port) +{ + struct circ_buf *xmit = &port->state->xmit; + + if (port->x_char) { + writeb(port->x_char, port->membase + VT8500_TXFIFO); + port->icount.tx++; + port->x_char = 0; + } + if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { + vt8500_stop_tx(port); + return; + } + + while ((vt8500_read(port, VT8500_URFIDX) & 0x1f) < 16) { + if (uart_circ_empty(xmit)) + break; + + writeb(xmit->buf[xmit->tail], port->membase + VT8500_TXFIFO); + + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); + port->icount.tx++; + } + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(port); + + if (uart_circ_empty(xmit)) + vt8500_stop_tx(port); +} + +static void vt8500_start_tx(struct uart_port *port) +{ + struct vt8500_port *vt8500_port = container_of(port, + struct vt8500_port, + uart); + + vt8500_port->ier &= ~TX_FIFO_INTS; + vt8500_write(port, vt8500_port->ier, VT8500_URIER); + handle_tx(port); + vt8500_port->ier |= TX_FIFO_INTS; + vt8500_write(port, vt8500_port->ier, VT8500_URIER); +} + +static void handle_delta_cts(struct uart_port *port) +{ + port->icount.cts++; + wake_up_interruptible(&port->state->port.delta_msr_wait); +} + +static irqreturn_t vt8500_irq(int irq, void *dev_id) +{ + struct uart_port *port = dev_id; + unsigned long isr; + + spin_lock(&port->lock); + isr = vt8500_read(port, VT8500_URISR); + + /* Acknowledge active status bits */ + vt8500_write(port, isr, VT8500_URISR); + + if (isr & RX_FIFO_INTS) + handle_rx(port); + if (isr & TX_FIFO_INTS) + handle_tx(port); + if (isr & TCTS) + handle_delta_cts(port); + + spin_unlock(&port->lock); + + return IRQ_HANDLED; +} + +static unsigned int vt8500_tx_empty(struct uart_port *port) +{ + return (vt8500_read(port, VT8500_URFIDX) & 0x1f) < 16 ? + TIOCSER_TEMT : 0; +} + +static unsigned int vt8500_get_mctrl(struct uart_port *port) +{ + unsigned int usr; + + usr = vt8500_read(port, VT8500_URUSR); + if (usr & (1 << 4)) + return TIOCM_CTS; + else + return 0; +} + +static void vt8500_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ +} + +static void vt8500_break_ctl(struct uart_port *port, int break_ctl) +{ + if (break_ctl) + vt8500_write(port, vt8500_read(port, VT8500_URLCR) | (1 << 9), + VT8500_URLCR); +} + +static int vt8500_set_baud_rate(struct uart_port *port, unsigned int baud) +{ + unsigned long div; + unsigned int loops = 1000; + + div = vt8500_read(port, VT8500_URDIV) & ~(0x3ff); + + if (unlikely((baud < 900) || (baud > 921600))) + div |= 7; + else + div |= (921600 / baud) - 1; + + while ((vt8500_read(port, VT8500_URUSR) & (1 << 5)) && --loops) + cpu_relax(); + vt8500_write(port, div, VT8500_URDIV); + + return baud; +} + +static int vt8500_startup(struct uart_port *port) +{ + struct vt8500_port *vt8500_port = + container_of(port, struct vt8500_port, uart); + int ret; + + snprintf(vt8500_port->name, sizeof(vt8500_port->name), + "vt8500_serial%d", port->line); + + ret = request_irq(port->irq, vt8500_irq, IRQF_TRIGGER_HIGH, + vt8500_port->name, port); + if (unlikely(ret)) + return ret; + + vt8500_write(port, 0x03, VT8500_URLCR); /* enable TX & RX */ + + return 0; +} + +static void vt8500_shutdown(struct uart_port *port) +{ + struct vt8500_port *vt8500_port = + container_of(port, struct vt8500_port, uart); + + vt8500_port->ier = 0; + + /* disable interrupts and FIFOs */ + vt8500_write(&vt8500_port->uart, 0, VT8500_URIER); + vt8500_write(&vt8500_port->uart, 0x880, VT8500_URFCR); + free_irq(port->irq, port); +} + +static void vt8500_set_termios(struct uart_port *port, + struct ktermios *termios, + struct ktermios *old) +{ + struct vt8500_port *vt8500_port = + container_of(port, struct vt8500_port, uart); + unsigned long flags; + unsigned int baud, lcr; + unsigned int loops = 1000; + + spin_lock_irqsave(&port->lock, flags); + + /* calculate and set baud rate */ + baud = uart_get_baud_rate(port, termios, old, 900, 921600); + baud = vt8500_set_baud_rate(port, baud); + if (tty_termios_baud_rate(termios)) + tty_termios_encode_baud_rate(termios, baud, baud); + + /* calculate parity */ + lcr = vt8500_read(&vt8500_port->uart, VT8500_URLCR); + lcr &= ~((1 << 5) | (1 << 4)); + if (termios->c_cflag & PARENB) { + lcr |= (1 << 4); + termios->c_cflag &= ~CMSPAR; + if (termios->c_cflag & PARODD) + lcr |= (1 << 5); + } + + /* calculate bits per char */ + lcr &= ~(1 << 2); + switch (termios->c_cflag & CSIZE) { + case CS7: + break; + case CS8: + default: + lcr |= (1 << 2); + termios->c_cflag &= ~CSIZE; + termios->c_cflag |= CS8; + break; + } + + /* calculate stop bits */ + lcr &= ~(1 << 3); + if (termios->c_cflag & CSTOPB) + lcr |= (1 << 3); + + /* set parity, bits per char, and stop bit */ + vt8500_write(&vt8500_port->uart, lcr, VT8500_URLCR); + + /* Configure status bits to ignore based on termio flags. */ + port->read_status_mask = 0; + if (termios->c_iflag & IGNPAR) + port->read_status_mask = FER | PER; + + uart_update_timeout(port, termios->c_cflag, baud); + + /* Reset FIFOs */ + vt8500_write(&vt8500_port->uart, 0x88c, VT8500_URFCR); + while ((vt8500_read(&vt8500_port->uart, VT8500_URFCR) & 0xc) + && --loops) + cpu_relax(); + + /* Every possible FIFO-related interrupt */ + vt8500_port->ier = RX_FIFO_INTS | TX_FIFO_INTS; + + /* + * CTS flow control + */ + if (UART_ENABLE_MS(&vt8500_port->uart, termios->c_cflag)) + vt8500_port->ier |= TCTS; + + vt8500_write(&vt8500_port->uart, 0x881, VT8500_URFCR); + vt8500_write(&vt8500_port->uart, vt8500_port->ier, VT8500_URIER); + + spin_unlock_irqrestore(&port->lock, flags); +} + +static const char *vt8500_type(struct uart_port *port) +{ + struct vt8500_port *vt8500_port = + container_of(port, struct vt8500_port, uart); + return vt8500_port->name; +} + +static void vt8500_release_port(struct uart_port *port) +{ +} + +static int vt8500_request_port(struct uart_port *port) +{ + return 0; +} + +static void vt8500_config_port(struct uart_port *port, int flags) +{ + port->type = PORT_VT8500; +} + +static int vt8500_verify_port(struct uart_port *port, + struct serial_struct *ser) +{ + if (unlikely(ser->type != PORT_UNKNOWN && ser->type != PORT_VT8500)) + return -EINVAL; + if (unlikely(port->irq != ser->irq)) + return -EINVAL; + return 0; +} + +static struct vt8500_port *vt8500_uart_ports[4]; +static struct uart_driver vt8500_uart_driver; + +#ifdef CONFIG_SERIAL_VT8500_CONSOLE + +static inline void wait_for_xmitr(struct uart_port *port) +{ + unsigned int status, tmout = 10000; + + /* Wait up to 10ms for the character(s) to be sent. */ + do { + status = vt8500_read(port, VT8500_URFIDX); + + if (--tmout == 0) + break; + udelay(1); + } while (status & 0x10); +} + +static void vt8500_console_putchar(struct uart_port *port, int c) +{ + wait_for_xmitr(port); + writeb(c, port->membase + VT8500_TXFIFO); +} + +static void vt8500_console_write(struct console *co, const char *s, + unsigned int count) +{ + struct vt8500_port *vt8500_port = vt8500_uart_ports[co->index]; + unsigned long ier; + + BUG_ON(co->index < 0 || co->index >= vt8500_uart_driver.nr); + + ier = vt8500_read(&vt8500_port->uart, VT8500_URIER); + vt8500_write(&vt8500_port->uart, VT8500_URIER, 0); + + uart_console_write(&vt8500_port->uart, s, count, + vt8500_console_putchar); + + /* + * Finally, wait for transmitter to become empty + * and switch back to FIFO + */ + wait_for_xmitr(&vt8500_port->uart); + vt8500_write(&vt8500_port->uart, VT8500_URIER, ier); +} + +static int __init vt8500_console_setup(struct console *co, char *options) +{ + struct vt8500_port *vt8500_port; + int baud = 9600; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + + if (unlikely(co->index >= vt8500_uart_driver.nr || co->index < 0)) + return -ENXIO; + + vt8500_port = vt8500_uart_ports[co->index]; + + if (!vt8500_port) + return -ENODEV; + + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); + + return uart_set_options(&vt8500_port->uart, + co, baud, parity, bits, flow); +} + +static struct console vt8500_console = { + .name = "ttyWMT", + .write = vt8500_console_write, + .device = uart_console_device, + .setup = vt8500_console_setup, + .flags = CON_PRINTBUFFER, + .index = -1, + .data = &vt8500_uart_driver, +}; + +#define VT8500_CONSOLE (&vt8500_console) + +#else +#define VT8500_CONSOLE NULL +#endif + +static struct uart_ops vt8500_uart_pops = { + .tx_empty = vt8500_tx_empty, + .set_mctrl = vt8500_set_mctrl, + .get_mctrl = vt8500_get_mctrl, + .stop_tx = vt8500_stop_tx, + .start_tx = vt8500_start_tx, + .stop_rx = vt8500_stop_rx, + .enable_ms = vt8500_enable_ms, + .break_ctl = vt8500_break_ctl, + .startup = vt8500_startup, + .shutdown = vt8500_shutdown, + .set_termios = vt8500_set_termios, + .type = vt8500_type, + .release_port = vt8500_release_port, + .request_port = vt8500_request_port, + .config_port = vt8500_config_port, + .verify_port = vt8500_verify_port, +}; + +static struct uart_driver vt8500_uart_driver = { + .owner = THIS_MODULE, + .driver_name = "vt8500_serial", + .dev_name = "ttyWMT", + .nr = 6, + .cons = VT8500_CONSOLE, +}; + +static int __init vt8500_serial_probe(struct platform_device *pdev) +{ + struct vt8500_port *vt8500_port; + struct resource *mmres, *irqres; + int ret; + + mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0); + irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0); + if (!mmres || !irqres) + return -ENODEV; + + vt8500_port = kzalloc(sizeof(struct vt8500_port), GFP_KERNEL); + if (!vt8500_port) + return -ENOMEM; + + vt8500_port->uart.type = PORT_VT8500; + vt8500_port->uart.iotype = UPIO_MEM; + vt8500_port->uart.mapbase = mmres->start; + vt8500_port->uart.irq = irqres->start; + vt8500_port->uart.fifosize = 16; + vt8500_port->uart.ops = &vt8500_uart_pops; + vt8500_port->uart.line = pdev->id; + vt8500_port->uart.dev = &pdev->dev; + vt8500_port->uart.flags = UPF_IOREMAP | UPF_BOOT_AUTOCONF; + vt8500_port->uart.uartclk = 24000000; + + snprintf(vt8500_port->name, sizeof(vt8500_port->name), + "VT8500 UART%d", pdev->id); + + vt8500_port->uart.membase = ioremap(mmres->start, + mmres->end - mmres->start + 1); + if (!vt8500_port->uart.membase) { + ret = -ENOMEM; + goto err; + } + + vt8500_uart_ports[pdev->id] = vt8500_port; + + uart_add_one_port(&vt8500_uart_driver, &vt8500_port->uart); + + platform_set_drvdata(pdev, vt8500_port); + + return 0; + +err: + kfree(vt8500_port); + return ret; +} + +static int __devexit vt8500_serial_remove(struct platform_device *pdev) +{ + struct vt8500_port *vt8500_port = platform_get_drvdata(pdev); + + platform_set_drvdata(pdev, NULL); + uart_remove_one_port(&vt8500_uart_driver, &vt8500_port->uart); + kfree(vt8500_port); + + return 0; +} + +static struct platform_driver vt8500_platform_driver = { + .probe = vt8500_serial_probe, + .remove = vt8500_serial_remove, + .driver = { + .name = "vt8500_serial", + .owner = THIS_MODULE, + }, +}; + +static int __init vt8500_serial_init(void) +{ + int ret; + + ret = uart_register_driver(&vt8500_uart_driver); + if (unlikely(ret)) + return ret; + + ret = platform_driver_register(&vt8500_platform_driver); + + if (unlikely(ret)) + uart_unregister_driver(&vt8500_uart_driver); + + return ret; +} + +static void __exit vt8500_serial_exit(void) +{ +#ifdef CONFIG_SERIAL_VT8500_CONSOLE + unregister_console(&vt8500_console); +#endif + platform_driver_unregister(&vt8500_platform_driver); + uart_unregister_driver(&vt8500_uart_driver); +} + +module_init(vt8500_serial_init); +module_exit(vt8500_serial_exit); + +MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>"); +MODULE_DESCRIPTION("Driver for vt8500 serial device"); +MODULE_LICENSE("GPL"); |