aboutsummaryrefslogtreecommitdiff
path: root/drivers/serial/vt8500_serial.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/serial/vt8500_serial.c')
-rw-r--r--drivers/serial/vt8500_serial.c648
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");
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-11-28 02:29:36 +0000