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    SubjectRe: [RFC][PATCH] Xilinx uartlite serial driver
    On Wed, 13 Sep 2006 15:39:09 +0200 Peter Korsgaard <jacmet@sunsite.dk> wrote:

    > >>>>> "Peter" == Peter Korsgaard <jacmet@sunsite.dk> writes:
    >
    > Olof> 2. There seems to be some timeout issues with tx_empty.
    >
    > Peter> Huh, that's odd - I haven't noticed that. I'll test it again and get
    > Peter> back to you.
    >
    > Ahh, found it - I didn't update the uart timeout in set_termios so it
    > used a very long timeout. Please give the updated patch a try.

    Looks good. Thanks.

    > Additional changes:
    > - Actually add the fixes I did in May on request of Russell
    > - Update for 2.6.18 (devfs and new IRQF defines)
    > - Removed the SERIAL_UARTLITE_NR_UARTS config option as we only have 4
    > minors reserved with lanana anyway.
    >
    > Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

    Acked-by: Olof Johansson <olof@lixom.net>

    >
    > diff -urpN linux-2.6.18-rc7.orig/drivers/serial/Kconfig linux-2.6.18-rc7/drivers/serial/Kconfig
    > --- linux-2.6.18-rc7.orig/drivers/serial/Kconfig 2006-09-13 15:01:24.000000000 +0200
    > +++ linux-2.6.18-rc7/drivers/serial/Kconfig 2006-09-13 15:01:51.000000000 +0200
    > @@ -511,6 +511,25 @@ config SERIAL_IMX_CONSOLE
    > your boot loader (lilo or loadlin) about how to pass options to the
    > kernel at boot time.)
    >
    > +config SERIAL_UARTLITE
    > + tristate "Xilinx uartlite serial port support"
    > + depends on PPC32
    > + select SERIAL_CORE
    > + help
    > + Say Y here if you want to use the Xilinx uartlite serial controller.
    > +
    > + To compile this driver as a module, choose M here: the
    > + module will be called uartlite.ko.
    > +
    > +config SERIAL_UARTLITE_CONSOLE
    > + bool "Support for console on Xilinx uartlite serial port"
    > + depends on SERIAL_UARTLITE=y
    > + select SERIAL_CORE_CONSOLE
    > + help
    > + Say Y here if you wish to use a Xilinx uartlite as the system
    > + console (the system console is the device which receives all kernel
    > + messages and warnings and which allows logins in single user mode).
    > +
    > config SERIAL_SUNCORE
    > bool
    > depends on SPARC
    > diff -urpN linux-2.6.18-rc7.orig/drivers/serial/Makefile linux-2.6.18-rc7/drivers/serial/Makefile
    > --- linux-2.6.18-rc7.orig/drivers/serial/Makefile 2006-09-13 15:01:24.000000000 +0200
    > +++ linux-2.6.18-rc7/drivers/serial/Makefile 2006-09-13 15:01:51.000000000 +0200
    > @@ -55,4 +55,5 @@ obj-$(CONFIG_SERIAL_VR41XX) += vr41xx_si
    > obj-$(CONFIG_SERIAL_SGI_IOC4) += ioc4_serial.o
    > obj-$(CONFIG_SERIAL_SGI_IOC3) += ioc3_serial.o
    > obj-$(CONFIG_SERIAL_AT91) += at91_serial.o
    > +obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o
    > obj-$(CONFIG_SERIAL_NETX) += netx-serial.o
    > diff -urpN linux-2.6.18-rc7.orig/drivers/serial/uartlite.c linux-2.6.18-rc7/drivers/serial/uartlite.c
    > --- linux-2.6.18-rc7.orig/drivers/serial/uartlite.c 1970-01-01 01:00:00.000000000 +0100
    > +++ linux-2.6.18-rc7/drivers/serial/uartlite.c 2006-09-13 15:01:51.000000000 +0200
    > @@ -0,0 +1,496 @@
    > +/*
    > + * 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 pt_regs *regs)
    > +{
    > + 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);
    > + free_irq(port->irq, port);
    > +}
    > +
    > +static void ulite_set_termios(struct uart_port *port, struct termios *termios,
    > + struct termios *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)
    > +{
    > + 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;
    > +
    > + if (co->index < 0 || co->index >= ULITE_NR_UARTS)
    > + return -EINVAL;
    > +
    > + port = &ports[co->index];
    > +
    > + /* not initialized yet? */
    > + if (!port->membase)
    > + return -ENODEV;
    > +
    > + return 0;
    > +}
    > +
    > +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;
    > +
    > + 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");
    > diff -urpN linux-2.6.18-rc7.orig/include/linux/serial_core.h linux-2.6.18-rc7/include/linux/serial_core.h
    > --- linux-2.6.18-rc7.orig/include/linux/serial_core.h 2006-09-13 15:01:25.000000000 +0200
    > +++ linux-2.6.18-rc7/include/linux/serial_core.h 2006-09-13 15:01:51.000000000 +0200
    > @@ -132,6 +132,8 @@
    >
    > #define PORT_S3C2412 73
    >
    > +/* Xilinx uartlite */
    > +#define PORT_UARTLITE 74
    >
    > #ifdef __KERNEL__
    >
    > diff -urpN linux-2.6.18-rc7.orig/MAINTAINERS linux-2.6.18-rc7/MAINTAINERS
    > --- linux-2.6.18-rc7.orig/MAINTAINERS 2006-09-13 15:01:20.000000000 +0200
    > +++ linux-2.6.18-rc7/MAINTAINERS 2006-09-13 15:01:51.000000000 +0200
    > @@ -3303,6 +3303,12 @@ W: http://oss.sgi.com/projects/xfs
    > T: git git://oss.sgi.com:8090/xfs/xfs-2.6
    > S: Supported
    >
    > +XILINX UARTLITE SERIAL DRIVER
    > +P: Peter Korsgaard
    > +M: jacmet@sunsite.dk
    > +L: linux-serial@vger.kernel.org
    > +S: Maintained
    > +
    > X86 3-LEVEL PAGING (PAE) SUPPORT
    > P: Ingo Molnar
    > M: mingo@redhat.com
    >
    -
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