--- /dev/null
+/*
+ * uartlite.c: Serial driver for Xilinx uartlite serial controller
+ *
+ * Peter Korsgaard <jacmet@sunsite.dk>
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/console.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+#include <linux/tty.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <asm/io.h>
+
+#define ULITE_MAJOR 204
+#define ULITE_MINOR 187
+#define ULITE_NR_UARTS 4
+
+/* For register details see datasheet:
+ http://www.xilinx.com/bvdocs/ipcenter/data_sheet/opb_uartlite.pdf
+*/
+#define ULITE_RX 0x00
+#define ULITE_TX 0x04
+#define ULITE_STATUS 0x08
+#define ULITE_CONTROL 0x0c
+
+#define ULITE_REGION 16
+
+#define ULITE_STATUS_RXVALID 0x01
+#define ULITE_STATUS_RXFULL 0x02
+#define ULITE_STATUS_TXEMPTY 0x04
+#define ULITE_STATUS_TXFULL 0x08
+#define ULITE_STATUS_IE 0x10
+#define ULITE_STATUS_OVERRUN 0x20
+#define ULITE_STATUS_FRAME 0x40
+#define ULITE_STATUS_PARITY 0x80
+
+#define ULITE_CONTROL_RST_TX 0x01
+#define ULITE_CONTROL_RST_RX 0x02
+#define ULITE_CONTROL_IE 0x10
+
+
+static struct uart_port ports[ULITE_NR_UARTS];
+
+static int ulite_receive(struct uart_port *port, int stat)
+{
+ struct tty_struct *tty = port->info->tty;
+ unsigned char ch = 0;
+ char flag = TTY_NORMAL;
+
+ if ((stat & (ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
+ | ULITE_STATUS_FRAME)) == 0)
+ return 0;
+
+ /* stats */
+ if (stat & ULITE_STATUS_RXVALID) {
+ port->icount.rx++;
+ ch = readb(port->membase + ULITE_RX);
+
+ if (stat & ULITE_STATUS_PARITY)
+ port->icount.parity++;
+ }
+
+ if (stat & ULITE_STATUS_OVERRUN)
+ port->icount.overrun++;
+
+ if (stat & ULITE_STATUS_FRAME)
+ port->icount.frame++;
+
+
+ /* drop byte with parity error if IGNPAR specificed */
+ if (stat & port->ignore_status_mask & ULITE_STATUS_PARITY)
+ stat &= ~ULITE_STATUS_RXVALID;
+
+ stat &= port->read_status_mask;
+
+ if (stat & ULITE_STATUS_PARITY)
+ flag = TTY_PARITY;
+
+
+ stat &= ~port->ignore_status_mask;
+
+ if (stat & ULITE_STATUS_RXVALID)
+ tty_insert_flip_char(tty, ch, flag);
+
+ if (stat & ULITE_STATUS_FRAME)
+ tty_insert_flip_char(tty, 0, TTY_FRAME);
+
+ if (stat & ULITE_STATUS_OVERRUN)
+ tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+
+ return 1;
+}
+
+static int ulite_transmit(struct uart_port *port, int stat)
+{
+ struct circ_buf *xmit = &port->info->xmit;
+
+ if (stat & ULITE_STATUS_TXFULL)
+ return 0;
+
+ if (port->x_char) {
+ writeb(port->x_char, port->membase + ULITE_TX);
+ port->x_char = 0;
+ port->icount.tx++;
+ return 1;
+ }
+
+ if (uart_circ_empty(xmit) || uart_tx_stopped(port))
+ return 0;
+
+ writeb(xmit->buf[xmit->tail], port->membase + ULITE_TX);
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
+ port->icount.tx++;
+
+ /* wake up */
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(port);
+
+ return 1;
+}
+
+static irqreturn_t ulite_isr(int irq, void *dev_id)
+{
+ struct uart_port *port = (struct uart_port *)dev_id;
+ int busy;
+
+ do {
+ int stat = readb(port->membase + ULITE_STATUS);
+ busy = ulite_receive(port, stat);
+ busy |= ulite_transmit(port, stat);
+ } while (busy);
+
+ tty_flip_buffer_push(port->info->tty);
+
+ return IRQ_HANDLED;
+}
+
+static unsigned int ulite_tx_empty(struct uart_port *port)
+{
+ unsigned long flags;
+ unsigned int ret;
+
+ spin_lock_irqsave(&port->lock, flags);
+ ret = readb(port->membase + ULITE_STATUS);
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0;
+}
+
+static unsigned int ulite_get_mctrl(struct uart_port *port)
+{
+ return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
+}
+
+static void ulite_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+ /* N/A */
+}
+
+static void ulite_stop_tx(struct uart_port *port)
+{
+ /* N/A */
+}
+
+static void ulite_start_tx(struct uart_port *port)
+{
+ ulite_transmit(port, readb(port->membase + ULITE_STATUS));
+}
+
+static void ulite_stop_rx(struct uart_port *port)
+{
+ /* don't forward any more data (like !CREAD) */
+ port->ignore_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
+ | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
+}
+
+static void ulite_enable_ms(struct uart_port *port)
+{
+ /* N/A */
+}
+
+static void ulite_break_ctl(struct uart_port *port, int ctl)
+{
+ /* N/A */
+}
+
+static int ulite_startup(struct uart_port *port)
+{
+ int ret;
+
+ ret = request_irq(port->irq, ulite_isr,
+ IRQF_DISABLED | IRQF_SAMPLE_RANDOM, "uartlite", port);
+ if (ret)
+ return ret;
+
+ writeb(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX,
+ port->membase + ULITE_CONTROL);
+ writeb(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
+
+ return 0;
+}
+
+static void ulite_shutdown(struct uart_port *port)
+{
+ writeb(0, port->membase + ULITE_CONTROL);
+ readb(port->membase + ULITE_CONTROL); /* dummy */
+ free_irq(port->irq, port);
+}
+
+static void ulite_set_termios(struct uart_port *port, struct ktermios *termios,
+ struct ktermios *old)
+{
+ unsigned long flags;
+ unsigned int baud;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
+ | ULITE_STATUS_TXFULL;
+
+ if (termios->c_iflag & INPCK)
+ port->read_status_mask |=
+ ULITE_STATUS_PARITY | ULITE_STATUS_FRAME;
+
+ port->ignore_status_mask = 0;
+ if (termios->c_iflag & IGNPAR)
+ port->ignore_status_mask |= ULITE_STATUS_PARITY
+ | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
+
+ /* ignore all characters if CREAD is not set */
+ if ((termios->c_cflag & CREAD) == 0)
+ port->ignore_status_mask |=
+ ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
+ | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
+
+ /* update timeout */
+ baud = uart_get_baud_rate(port, termios, old, 0, 460800);
+ uart_update_timeout(port, termios->c_cflag, baud);
+
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *ulite_type(struct uart_port *port)
+{
+ return port->type == PORT_UARTLITE ? "uartlite" : NULL;
+}
+
+static void ulite_release_port(struct uart_port *port)
+{
+ release_mem_region(port->mapbase, ULITE_REGION);
+ iounmap(port->membase);
+ port->membase = 0;
+}
+
+static int ulite_request_port(struct uart_port *port)
+{
+ if (!request_mem_region(port->mapbase, ULITE_REGION, "uartlite")) {
+ dev_err(port->dev, "Memory region busy\n");
+ return -EBUSY;
+ }
+
+ port->membase = ioremap(port->mapbase, ULITE_REGION);
+ if (!port->membase) {
+ dev_err(port->dev, "Unable to map registers\n");
+ release_mem_region(port->mapbase, ULITE_REGION);
+ return -EBUSY;
+ }
+
+ return 0;
+}
+
+static void ulite_config_port(struct uart_port *port, int flags)
+{
+ if (!ulite_request_port(port))
+ port->type = PORT_UARTLITE;
+}
+
+static int ulite_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 ulite_ops = {
+ .tx_empty = ulite_tx_empty,
+ .set_mctrl = ulite_set_mctrl,
+ .get_mctrl = ulite_get_mctrl,
+ .stop_tx = ulite_stop_tx,
+ .start_tx = ulite_start_tx,
+ .stop_rx = ulite_stop_rx,
+ .enable_ms = ulite_enable_ms,
+ .break_ctl = ulite_break_ctl,
+ .startup = ulite_startup,
+ .shutdown = ulite_shutdown,
+ .set_termios = ulite_set_termios,
+ .type = ulite_type,
+ .release_port = ulite_release_port,
+ .request_port = ulite_request_port,
+ .config_port = ulite_config_port,
+ .verify_port = ulite_verify_port
+};
+
+#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
+static void ulite_console_wait_tx(struct uart_port *port)
+{
+ int i;
+
+ /* wait up to 10ms for the character(s) to be sent */
+ for (i = 0; i < 10000; i++) {
+ if (readb(port->membase + ULITE_STATUS) & ULITE_STATUS_TXEMPTY)
+ break;
+ udelay(1);
+ }
+}
+
+static void ulite_console_putchar(struct uart_port *port, int ch)
+{
+ ulite_console_wait_tx(port);
+ writeb(ch, port->membase + ULITE_TX);
+}
+
+static void ulite_console_write(struct console *co, const char *s,
+ unsigned int count)
+{
+ struct uart_port *port = &ports[co->index];
+ unsigned long flags;
+ unsigned int ier;
+ int locked = 1;
+
+ if (oops_in_progress) {
+ locked = spin_trylock_irqsave(&port->lock, flags);
+ } else
+ spin_lock_irqsave(&port->lock, flags);
+
+ /* save and disable interrupt */
+ ier = readb(port->membase + ULITE_STATUS) & ULITE_STATUS_IE;
+ writeb(0, port->membase + ULITE_CONTROL);
+
+ uart_console_write(port, s, count, ulite_console_putchar);
+
+ ulite_console_wait_tx(port);
+
+ /* restore interrupt state */
+ if (ier)
+ writeb(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
+
+ if (locked)
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static int __init ulite_console_setup(struct console *co, char *options)
+{
+ struct uart_port *port;
+ int baud = 9600;
+ int bits = 8;
+ int parity = 'n';
+ int flow = 'n';
+
+ if (co->index < 0 || co->index >= ULITE_NR_UARTS)
+ return -EINVAL;
+
+ port = &ports[co->index];
+
+ /* not initialized yet? */
+ if (!port->membase)
+ return -ENODEV;
+
+ if (options)
+ uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+ return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver ulite_uart_driver;
+
+static struct console ulite_console = {
+ .name = "ttyUL",
+ .write = ulite_console_write,
+ .device = uart_console_device,
+ .setup = ulite_console_setup,
+ .flags = CON_PRINTBUFFER,
+ .index = -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */
+ .data = &ulite_uart_driver,
+};
+
+static int __init ulite_console_init(void)
+{
+ register_console(&ulite_console);
+ return 0;
+}
+
+console_initcall(ulite_console_init);
+
+#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
+
+static struct uart_driver ulite_uart_driver = {
+ .owner = THIS_MODULE,
+ .driver_name = "uartlite",
+ .dev_name = "ttyUL",
+ .major = ULITE_MAJOR,
+ .minor = ULITE_MINOR,
+ .nr = ULITE_NR_UARTS,
+#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
+ .cons = &ulite_console,
+#endif
+};
+
+static int __devinit ulite_probe(struct platform_device *pdev)
+{
+ struct resource *res, *res2;
+ struct uart_port *port;
+
+ if (pdev->id < 0 || pdev->id >= ULITE_NR_UARTS)
+ return -EINVAL;
+
+ if (ports[pdev->id].membase)
+ return -EBUSY;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+
+ res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+ if (!res2)
+ return -ENODEV;
+
+ port = &ports[pdev->id];
+
+ port->fifosize = 16;
+ port->regshift = 2;
+ port->iotype = UPIO_MEM;
+ port->iobase = 1; /* mark port in use */
+ port->mapbase = res->start;
+ port->membase = 0;
+ port->ops = &ulite_ops;
+ port->irq = res2->start;
+ port->flags = UPF_BOOT_AUTOCONF;
+ port->dev = &pdev->dev;
+ port->type = PORT_UNKNOWN;
+ port->line = pdev->id;
+
+ uart_add_one_port(&ulite_uart_driver, port);
+ platform_set_drvdata(pdev, port);
+
+ return 0;
+}
+
+static int ulite_remove(struct platform_device *pdev)
+{
+ struct uart_port *port = platform_get_drvdata(pdev);
+
+ platform_set_drvdata(pdev, NULL);
+
+ if (port)
+ uart_remove_one_port(&ulite_uart_driver, port);
+
+ /* mark port as free */
+ port->membase = 0;
+
+ return 0;
+}
+
+static struct platform_driver ulite_platform_driver = {
+ .probe = ulite_probe,
+ .remove = ulite_remove,
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "uartlite",
+ },
+};
+
+int __init ulite_init(void)
+{
+ int ret;
+
+ ret = uart_register_driver(&ulite_uart_driver);
+ if (ret)
+ return ret;
+
+ ret = platform_driver_register(&ulite_platform_driver);
+ if (ret)
+ uart_unregister_driver(&ulite_uart_driver);
+
+ return ret;
+}
+
+void __exit ulite_exit(void)
+{
+ platform_driver_unregister(&ulite_platform_driver);
+ uart_unregister_driver(&ulite_uart_driver);
+}
+
+module_init(ulite_init);
+module_exit(ulite_exit);
+
+MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
+MODULE_DESCRIPTION("Xilinx uartlite serial driver");
+MODULE_LICENSE("GPL");
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