[PATCH] Add support for the nwp serial device

Arnd Bergmann
2008-11-20T14:01:23Z

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.

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>
--
1.5.6.5

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