Re: [PATCH] Add support for the nwp serial device

Benjamin Herrenschmidt
2008-11-22T22:04:51Z

On Thu, 2008-11-20 at 15:01 +0100, Arnd Bergmann wrote:
> From: Benjamin Krill <ben@codiert.org>
>
> This patch adds support for the nwp serial device which is connected to
> a DCR bus. It uses the of_serial device driver to determine necessary
> properties from the device tree. The supported device is added as serial
> port number 84.

I don't suppose it would have been useful to at least somewhere mention
what "NWP" serial is and where it can be found ? :-)

Cheers,
Ben.

> Signed-off-by: Benjamin Krill <ben@codiert.org>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>
> Since the serial drivers are still orphaned, should we merge this through
> the powerpc tree?
>
> ---
> drivers/serial/Kconfig | 11 +-
> drivers/serial/Makefile | 1 +
> drivers/serial/nwpserial.c | 443 +++++++++++++++++++++++++++++++++++++++++++
> drivers/serial/of_serial.c | 18 ++
> include/linux/nwpserial.h | 18 ++
> include/linux/serial_core.h | 3 +
> 6 files changed, 493 insertions(+), 1 deletions(-)
> create mode 100644 drivers/serial/nwpserial.c
> create mode 100644 include/linux/nwpserial.h
>
> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> index 579d63a..45dcc8d 100644
> --- a/drivers/serial/Kconfig
> +++ b/drivers/serial/Kconfig
> @@ -1297,13 +1297,22 @@ config SERIAL_NETX_CONSOLE
> config SERIAL_OF_PLATFORM
> tristate "Serial port on Open Firmware platform bus"
> depends on PPC_OF
> - depends on SERIAL_8250
> + depends on SERIAL_8250 || SERIAL_OF_PLATFORM_NWPSERIAL
> help
> If you have a PowerPC based system that has serial ports
> on a platform specific bus, you should enable this option.
> Currently, only 8250 compatible ports are supported, but
> others can easily be added.
>
> +config SERIAL_OF_PLATFORM_NWPSERIAL
> + tristate "NWP serial port driver"
> + depends on PPC_OF && PPC_DCR
> + select SERIAL_OF_PLATFORM
> + select SERIAL_CORE_CONSOLE
> + select SERIAL_CORE
> + help
> + This driver supports the nwp serial port.
> +
> config SERIAL_QE
> tristate "Freescale QUICC Engine serial port support"
> depends on QUICC_ENGINE
> diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
> index 0c17c8d..05da19d 100644
> --- a/drivers/serial/Makefile
> +++ b/drivers/serial/Makefile
> @@ -70,6 +70,7 @@ obj-$(CONFIG_SERIAL_ATMEL) += atmel_serial.o
> obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o
> obj-$(CONFIG_SERIAL_NETX) += netx-serial.o
> obj-$(CONFIG_SERIAL_OF_PLATFORM) += of_serial.o
> +obj-$(CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL) += nwpserial.o
> obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o
> obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o
> obj-$(CONFIG_SERIAL_QE) += ucc_uart.o
> diff --git a/drivers/serial/nwpserial.c b/drivers/serial/nwpserial.c
> new file mode 100644
> index 0000000..5f2ecab
> --- /dev/null
> +++ b/drivers/serial/nwpserial.c
> @@ -0,0 +1,443 @@
> +/*
> + * Serial Port driver for a NWP uart device
> + *
> + * Copyright (C) 2008 IBM Corp., Benjamin Krill <ben@codiert.org>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version
> + * 2 of the License, or (at your option) any later version.
> + *
> + */
> +#include <linux/console.h>
> +#include <linux/serial.h>
> +#include <linux/serial_reg.h>
> +#include <linux/serial_core.h>
> +#include <linux/tty.h>
> +#include <linux/irqreturn.h>
> +#include <linux/mutex.h>
> +#include <linux/of_platform.h>
> +#include <linux/of_device.h>
> +#include <linux/nwpserial.h>
> +#include <asm/prom.h>
> +#include <asm/dcr.h>
> +
> +#define NWPSERIAL_NR 2
> +
> +#define NWPSERIAL_STATUS_RXVALID 0x1
> +#define NWPSERIAL_STATUS_TXFULL 0x2
> +
> +struct nwpserial_port {
> + struct uart_port port;
> + dcr_host_t dcr_host;
> + unsigned int ier;
> + unsigned int mcr;
> +};
> +
> +static DEFINE_MUTEX(nwpserial_mutex);
> +static struct nwpserial_port nwpserial_ports[NWPSERIAL_NR];
> +
> +static void nwpserial_console_putchar(struct uart_port *port, int c)
> +{
> + struct nwpserial_port *up = container_of(port, struct nwpserial_port, port);
> + /* check if tx buffer is full */
> + while ((dcr_read(up->dcr_host, UART_LSR) & UART_LSR_THRE) == 0)
> + cpu_relax();
> + dcr_write(up->dcr_host, UART_TX, c);
> + up->port.icount.tx++;
> +}
> +
> +static void
> +nwpserial_console_write(struct console *co, const char *s, unsigned int count)
> +{
> + struct nwpserial_port *up = &nwpserial_ports[co->index];
> + unsigned long flags;
> + int locked = 1;
> +
> + if (oops_in_progress)
> + locked = spin_trylock_irqsave(&up->port.lock, flags);
> + else
> + spin_lock_irqsave(&up->port.lock, flags);
> +
> + /* save and disable interrupt */
> + up->ier = dcr_read(up->dcr_host, UART_IER);
> + dcr_write(up->dcr_host, UART_IER, up->ier & ~UART_IER_RDI);
> +
> + uart_console_write(&up->port, s, count, nwpserial_console_putchar);
> +
> + /* wait for transmitter to become emtpy */
> + while ((dcr_read(up->dcr_host, UART_LSR) & UART_LSR_THRE) == 0)
> + cpu_relax();
> +
> + /* restore interrupt state */
> + dcr_write(up->dcr_host, UART_IER, up->ier);
> +
> + if (locked)
> + spin_unlock_irqrestore(&up->port.lock, flags);
> +}
> +
> +static struct uart_driver nwpserial_reg;
> +static struct console nwpserial_console = {
> + .name = "ttySQ",
> + .write = nwpserial_console_write,
> + .device = uart_console_device,
> + .flags = CON_PRINTBUFFER,
> + .index = -1,
> + .data = &nwpserial_reg,
> +};
> +
> +/*******************************************************************************/
> +
> +static int nwpserial_request_port(struct uart_port *port)
> +{
> + return 0;
> +}
> +
> +static void nwpserial_release_port(struct uart_port *port)
> +{
> + /* N/A */
> +}
> +
> +static void nwpserial_config_port(struct uart_port *port, int flags)
> +{
> + port->type = PORT_NWPSERIAL;
> +}
> +
> +static irqreturn_t nwpserial_interrupt(int irq, void *dev_id)
> +{
> + struct nwpserial_port *up = dev_id;//container_of(dev_id, struct nwpserial_port, port);
> + struct tty_struct *tty = up->port.info->port.tty;
> + irqreturn_t ret;
> + unsigned int iir;
> + unsigned char ch;
> +
> + spin_lock(&up->port.lock);
> +
> + /* check if the uart was the interrupt source. */
> + iir = dcr_read(up->dcr_host, UART_IIR);
> + if (!iir) {
> + ret = IRQ_NONE;
> + goto out;
> + }
> +
> + do {
> + up->port.icount.rx++;
> + ch = dcr_read(up->dcr_host, UART_RX);
> + if (up->port.ignore_status_mask != NWPSERIAL_STATUS_RXVALID)
> + tty_insert_flip_char(tty, ch, TTY_NORMAL);
> + } while (dcr_read(up->dcr_host, UART_RX) & UART_LSR_DR);
> +
> + tty_flip_buffer_push(tty);
> + ret = IRQ_HANDLED;
> +
> +out:
> + spin_unlock(&up->port.lock);
> + return ret;
> +}
> +
> +static int nwpserial_startup(struct uart_port *port)
> +{
> + struct nwpserial_port *up = container_of(port, struct nwpserial_port, port);
> + int err;
> +
> + /* disable flow control by default */
> + up->mcr = dcr_read(up->dcr_host, UART_MCR) & ~UART_MCR_AFE;
> + dcr_write(up->dcr_host, UART_MCR, up->mcr);
> +
> + /* register interrupt handler */
> + err = request_irq(up->port.irq, nwpserial_interrupt,
> + IRQF_SHARED, "nwpserial", up);
> + if (err) {
> + free_irq(up->port.irq, port);
> + return err;
> + }
> +
> + /* enable interrupts */
> + up->ier = UART_IER_RDI;
> + dcr_write(up->dcr_host, UART_IER, up->ier);
> +
> + /* enable receiving */
> + up->port.ignore_status_mask &= ~NWPSERIAL_STATUS_RXVALID;
> +
> + return 0;
> +}
> +
> +static void nwpserial_shutdown(struct uart_port *port)
> +{
> + struct nwpserial_port *up = container_of(port, struct nwpserial_port, port);
> +
> + /* disable receiving */
> + up->port.ignore_status_mask |= NWPSERIAL_STATUS_RXVALID;
> +
> + /* disable interrupts from this port */
> + up->ier = 0;
> + dcr_write(up->dcr_host, UART_IER, up->ier);
> +
> + /* free irq */
> + free_irq(up->port.irq, port);
> +}
> +
> +static int nwpserial_verify_port(struct uart_port *port, struct serial_struct *ser)
> +{
> + return -EINVAL;
> +}
> +
> +static const char *nwpserial_type(struct uart_port *port)
> +{
> + return port->type == PORT_NWPSERIAL ? "nwpserial" : NULL;
> +}
> +
> +static void nwpserial_set_termios(struct uart_port *port, struct ktermios *termios,
> + struct ktermios *old)
> +{
> + struct nwpserial_port *up = container_of(port, struct nwpserial_port, port);
> +
> + up->port.read_status_mask = NWPSERIAL_STATUS_RXVALID | NWPSERIAL_STATUS_TXFULL;
> +
> + up->port.ignore_status_mask = 0;
> + /* ignore all characters if CREAD is not set */
> + if ((termios->c_cflag & CREAD) == 0)
> + up->port.ignore_status_mask |= NWPSERIAL_STATUS_RXVALID;
> +}
> +
> +static void nwpserial_break_ctl(struct uart_port *port, int ctl)
> +{
> + /* N/A */
> +}
> +
> +static void nwpserial_enable_ms(struct uart_port *port)
> +{
> + /* N/A */
> +}
> +
> +static void nwpserial_stop_rx(struct uart_port *port)
> +{
> + struct nwpserial_port *up = container_of(port, struct nwpserial_port, port);
> + /* don't forward any more data (like !CREAD) */
> + up->port.ignore_status_mask = NWPSERIAL_STATUS_RXVALID;
> +}
> +
> +static void nwpserial_putchar(struct nwpserial_port *up, unsigned char c)
> +{
> + /* check if tx buffer is full */
> + while ((dcr_read(up->dcr_host, UART_LSR) & UART_LSR_THRE) == 0)
> + cpu_relax();
> + dcr_write(up->dcr_host, UART_TX, c);
> + up->port.icount.tx++;
> +}
> +
> +static void nwpserial_start_tx(struct uart_port *port)
> +{
> + struct nwpserial_port *up = container_of(port, struct nwpserial_port, port);
> + struct circ_buf *xmit = &up->port.info->xmit;
> +
> + if (port->x_char) {
> + nwpserial_putchar(up, up->port.x_char);
> + port->x_char = 0;
> + }
> +
> + while (!(uart_circ_empty(xmit) || uart_tx_stopped(&up->port))) {
> + nwpserial_putchar(up, xmit->buf[xmit->tail]);
> + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
> + }
> +}
> +
> +static unsigned int nwpserial_get_mctrl(struct uart_port *port)
> +{
> + return 0;
> +}
> +
> +static void nwpserial_set_mctrl(struct uart_port *port, unsigned int mctrl)
> +{
> + /* N/A */
> +}
> +
> +static void nwpserial_stop_tx(struct uart_port *port)
> +{
> + /* N/A */
> +}
> +
> +static unsigned int nwpserial_tx_empty(struct uart_port *port)
> +{
> + struct nwpserial_port *up = container_of(port, struct nwpserial_port, port);
> + unsigned long flags;
> + int ret;
> +
> + spin_lock_irqsave(&up->port.lock, flags);
> + ret = dcr_read(up->dcr_host, UART_LSR);
> + spin_unlock_irqrestore(&up->port.lock, flags);
> +
> + return ret & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
> +}
> +
> +static struct uart_ops nwpserial_pops = {
> + .tx_empty = nwpserial_tx_empty,
> + .set_mctrl = nwpserial_set_mctrl,
> + .get_mctrl = nwpserial_get_mctrl,
> + .stop_tx = nwpserial_stop_tx,
> + .start_tx = nwpserial_start_tx,
> + .stop_rx = nwpserial_stop_rx,
> + .enable_ms = nwpserial_enable_ms,
> + .break_ctl = nwpserial_break_ctl,
> + .startup = nwpserial_startup,
> + .shutdown = nwpserial_shutdown,
> + .set_termios = nwpserial_set_termios,
> + .type = nwpserial_type,
> + .release_port = nwpserial_release_port,
> + .request_port = nwpserial_request_port,
> + .config_port = nwpserial_config_port,
> + .verify_port = nwpserial_verify_port,
> +};
> +
> +static struct uart_driver nwpserial_reg = {
> + .owner = THIS_MODULE,
> + .driver_name = "nwpserial",
> + .dev_name = "ttySQ",
> + .major = TTY_MAJOR,
> + .minor = 68,
> + .nr = NWPSERIAL_NR,
> + .cons = &nwpserial_console,
> +};
> +
> +int
> +nwpserial_register_port(struct uart_port *port)
> +{
> + struct nwpserial_port *up = NULL;
> + int ret = -1;
> + int i;
> + static int first = 1;
> + int dcr_len;
> + int dcr_base;
> + struct device_node *dn;
> +
> + mutex_lock(&nwpserial_mutex);
> +
> + dn = to_of_device(port->dev)->node;
> + if (dn == NULL)
> + goto out;
> +
> + /* get dcr base. */
> + dcr_base = dcr_resource_start(dn, 0);
> +
> + /* find matching entry */
> + for (i = 0; i < NWPSERIAL_NR; i++)
> + if (nwpserial_ports[i].port.iobase == dcr_base) {
> + up = &nwpserial_ports[i];
> + break;
> + }
> +
> + /* we didn't find a mtching entry, search for a free port */
> + if (up == NULL)
> + for (i = 0; i < NWPSERIAL_NR; i++)
> + if (nwpserial_ports[i].port.type == PORT_UNKNOWN &&
> + nwpserial_ports[i].port.iobase == 0) {
> + up = &nwpserial_ports[i];
> + break;
> + }
> +
> + if (up == NULL) {
> + ret = -EBUSY;
> + goto out;
> + }
> +
> + if (first)
> + uart_register_driver(&nwpserial_reg);
> + first = 0;
> +
> + up->port.membase = port->membase;
> + up->port.irq = port->irq;
> + up->port.uartclk = port->uartclk;
> + up->port.fifosize = port->fifosize;
> + up->port.regshift = port->regshift;
> + up->port.iotype = port->iotype;
> + up->port.flags = port->flags;
> + up->port.mapbase = port->mapbase;
> + up->port.private_data = port->private_data;
> +
> + if (port->dev)
> + up->port.dev = port->dev;
> +
> + if (up->port.iobase != dcr_base) {
> + up->port.ops = &nwpserial_pops;
> + up->port.fifosize = 16;
> +
> + spin_lock_init(&up->port.lock);
> +
> + up->port.iobase = dcr_base;
> + dcr_len = dcr_resource_len(dn, 0);
> +
> + up->dcr_host = dcr_map(dn, dcr_base, dcr_len);
> + if (!DCR_MAP_OK(up->dcr_host)) {
> + printk("Cannot map DCR resources for NWPSERIAL");
> + goto out;
> + }
> + }
> +
> + ret = uart_add_one_port(&nwpserial_reg, &up->port);
> + if (ret == 0)
> + ret = up->port.line;
> +
> +out:
> + mutex_unlock(&nwpserial_mutex);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL(nwpserial_register_port);
> +
> +void nwpserial_unregister_port(int line)
> +{
> + struct nwpserial_port *up = &nwpserial_ports[line];
> + mutex_lock(&nwpserial_mutex);
> + uart_remove_one_port(&nwpserial_reg, &up->port);
> +
> + up->port.type = PORT_UNKNOWN;
> +
> + mutex_unlock(&nwpserial_mutex);
> +}
> +EXPORT_SYMBOL(nwpserial_unregister_port);
> +
> +static int __init nwpserial_console_init(void)
> +{
> + struct nwpserial_port *up = NULL;
> + struct device_node *dn;
> + const char *name;
> + int dcr_base;
> + int dcr_len;
> + int i;
> +
> + /* search for a free port */
> + for (i = 0; i < NWPSERIAL_NR; i++)
> + if (nwpserial_ports[i].port.type == PORT_UNKNOWN) {
> + up = &nwpserial_ports[i];
> + break;
> + }
> +
> + if (up == NULL)
> + return -1;
> +
> + name = of_get_property(of_chosen, "linux,stdout-path", NULL);
> + if (name == NULL)
> + return -1;
> +
> + dn = of_find_node_by_path(name);
> + if (!dn)
> + return -1;
> +
> + spin_lock_init(&up->port.lock);
> + up->port.ops = &nwpserial_pops;
> + up->port.type = PORT_NWPSERIAL;
> + up->port.fifosize = 16;
> +
> + dcr_base = dcr_resource_start(dn, 0);
> + dcr_len = dcr_resource_len(dn, 0);
> + up->port.iobase = dcr_base;
> +
> + up->dcr_host = dcr_map(dn, dcr_base, dcr_len);
> + if (!DCR_MAP_OK(up->dcr_host)) {
> + printk("Cannot map DCR resources for SERIAL");
> + return -1;
> + }
> + register_console(&nwpserial_console);
> + return 0;
> +}
> +console_initcall(nwpserial_console_init);
> diff --git a/drivers/serial/of_serial.c b/drivers/serial/of_serial.c
> index 8fa0ff5..bb56231 100644
> --- a/drivers/serial/of_serial.c
> +++ b/drivers/serial/of_serial.c
> @@ -14,6 +14,7 @@
> #include <linux/serial_core.h>
> #include <linux/serial_8250.h>
> #include <linux/of_platform.h>
> +#include <linux/nwpserial.h>
>
> #include <asm/prom.h>
>
> @@ -99,9 +100,16 @@ static int __devinit of_platform_serial_probe(struct of_device *ofdev,
> goto out;
>
> switch (port_type) {
> +#ifdef CONFIG_SERIAL_8250
> case PORT_8250 ... PORT_MAX_8250:
> ret = serial8250_register_port(&port);
> break;
> +#endif
> +#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
> + case PORT_NWPSERIAL:
> + ret = nwpserial_register_port(&port);
> + break;
> +#endif
> default:
> /* need to add code for these */
> case PORT_UNKNOWN:
> @@ -129,9 +137,16 @@ static int of_platform_serial_remove(struct of_device *ofdev)
> {
> struct of_serial_info *info = ofdev->dev.driver_data;
> switch (info->type) {
> +#ifdef CONFIG_SERIAL_8250
> case PORT_8250 ... PORT_MAX_8250:
> serial8250_unregister_port(info->line);
> break;
> +#endif
> +#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
> + case PORT_NWPSERIAL:
> + nwpserial_unregister_port(info->line);
> + break;
> +#endif
> default:
> /* need to add code for these */
> break;
> @@ -148,6 +163,9 @@ static struct of_device_id __devinitdata of_platform_serial_table[] = {
> { .type = "serial", .compatible = "ns16450", .data = (void *)PORT_16450, },
> { .type = "serial", .compatible = "ns16550", .data = (void *)PORT_16550, },
> { .type = "serial", .compatible = "ns16750", .data = (void *)PORT_16750, },
> +#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
> + { .type = "serial", .compatible = "ibm,qpace-nwpserial", .data = (void *)PORT_NWPSERIAL, },
> +#endif
> { .type = "serial", .data = (void *)PORT_UNKNOWN, },
> { /* end of list */ },
> };
> diff --git a/include/linux/nwpserial.h b/include/linux/nwpserial.h
> new file mode 100644
> index 0000000..9acb215
> --- /dev/null
> +++ b/include/linux/nwpserial.h
> @@ -0,0 +1,18 @@
> +/*
> + * Serial Port driver for a NWP uart device
> + *
> + * Copyright (C) 2008 IBM Corp., Benjamin Krill <ben@codiert.org>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version
> + * 2 of the License, or (at your option) any later version.
> + *
> + */
> +#ifndef _NWPSERIAL_H
> +#define _NWPSERIAL_H
> +
> +int nwpserial_register_port(struct uart_port *port);
> +void nwpserial_unregister_port(int line);
> +
> +#endif /* _NWPSERIAL_H */
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> index 4e4f127..4621faf 100644
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -158,6 +158,9 @@
> /* SH-SCI */
> #define PORT_SCIFA 83
>
> +/* NWPSERIAL */
> +#define PORT_NWPSERIAL 84
> +
> #ifdef __KERNEL__
>
> #include <linux/compiler.h>