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Subject[PATCH] PPS: UART PPS support replaced by new N_PPS line discipline.
Starting from now the PPS signal routed to the DCD pin of a serial
ports is managed by a dedicated line discipline.

Signed-off-by: Rodolfo Giometti <giometti@linux.it>
---
drivers/pps/clients/Kconfig | 9 +--
drivers/pps/clients/Makefile | 1 +
drivers/pps/clients/pps-ldisc.c | 172 +++++++++++++++++++++++++++++++++++++++
drivers/serial/serial_core.c | 78 ------------------
include/linux/serial_core.h | 39 ++-------
5 files changed, 184 insertions(+), 115 deletions(-)
create mode 100644 drivers/pps/clients/pps-ldisc.c
diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig
index 09ba5c3..b4054cd 100644
--- a/drivers/pps/clients/Kconfig
+++ b/drivers/pps/clients/Kconfig
@@ -15,12 +15,9 @@ config PPS_CLIENT_KTIMER
This driver can also be built as a module. If so, the module
will be called ktimer.ko.

-comment "UART serial support (forced off)"
- depends on ! (SERIAL_CORE != n && !(PPS = m && SERIAL_CORE = y))
-
-config PPS_CLIENT_UART
- bool "UART serial support"
- depends on SERIAL_CORE != n && !(PPS = m && SERIAL_CORE = y)
+config PPS_CLIENT_LDISC
+ tristate "PPS line discipline"
+ depends on PPS
help
If you say yes here you get support for a PPS source connected
with the CD (Carrier Detect) pin of your serial port.
diff --git a/drivers/pps/clients/Makefile b/drivers/pps/clients/Makefile
index f3c1e39..9f5b988 100644
--- a/drivers/pps/clients/Makefile
+++ b/drivers/pps/clients/Makefile
@@ -3,6 +3,7 @@
#

obj-$(CONFIG_PPS_CLIENT_KTIMER) += ktimer.o
+obj-$(CONFIG_PPS_CLIENT_LDISC) += pps-ldisc.o

ifeq ($(CONFIG_PPS_DEBUG),y)
EXTRA_CFLAGS += -DDEBUG
diff --git a/drivers/pps/clients/pps-ldisc.c b/drivers/pps/clients/pps-ldisc.c
new file mode 100644
index 0000000..1a4c5cc
--- /dev/null
+++ b/drivers/pps/clients/pps-ldisc.c
@@ -0,0 +1,172 @@
+/*
+ * pps-ldisc.c -- PPS line discipline
+ *
+ *
+ * Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/serial_core.h>
+#include <linux/tty.h>
+#include <linux/pps.h>
+
+#define PPS_TTY_MAGIC 0x0001
+
+#ifdef CONFIG_PPS_IRQ_EVENTS
+
+static void pps_tty_dcd_change(struct uart_port *port, unsigned int status,
+ struct timespec *ts)
+{
+ int id = (int) port->info->tty->disc_data;
+
+ pps_event(id, &pps_irq_ts[port->irq],
+ status ? PPS_CAPTUREASSERT : PPS_CAPTURECLEAR, port);
+
+ pr_debug("[IRQev] PPS %s at %lu on source #%d\n",
+ status ? "assert" : "clear", jiffies, id);
+}
+
+#else
+
+static void pps_tty_dcd_change(struct uart_port *port, unsigned int status,
+ struct timespec *ts)
+{
+ int id = (int) port->info->tty->disc_data;
+ struct timespec __ts;
+ struct pps_ktime pps_ts;
+
+ /* First of all we get the time stamp... */
+ getnstimeofday(&__ts);
+
+ /* Does caller give us a timestamp? */
+ if (ts) { /* Yes. Let's use it! */
+ pps_ts.sec = ts->tv_sec;
+ pps_ts.nsec = ts->tv_nsec;
+ } else { /* No. Do it ourself! */
+ pps_ts.sec = __ts.tv_sec;
+ pps_ts.nsec = __ts.tv_nsec;
+ }
+
+ /* Now do the PPS event report */
+ pps_event(id, &pps_ts, status ? PPS_CAPTUREASSERT : PPS_CAPTURECLEAR,
+ port);
+
+ pr_debug("[STDev] PPS %s at %lu on source #%d\n",
+ status ? "assert" : "clear", jiffies, id);
+}
+
+#endif /* CONFIG_PPS_IRQ_EVENTS */
+
+static int pps_tty_open(struct tty_struct *tty)
+{
+ struct pps_source_info info;
+ struct tty_driver *drv = tty->driver;
+ int index = tty->index + drv->name_base;
+ int ret;
+
+ info.owner = THIS_MODULE;
+ info.dev = NULL;
+ snprintf(info.name, PPS_MAX_NAME_LEN, "%s%d", drv->driver_name, index);
+ snprintf(info.path, PPS_MAX_NAME_LEN, "/dev/%s%d", drv->name, index);
+ info.mode = PPS_CAPTUREBOTH | \
+ PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
+ PPS_CANWAIT | PPS_TSFMT_TSPEC;
+
+ ret = pps_register_source(&info, PPS_CAPTUREBOTH | \
+ PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
+ if (ret < 0) {
+ pr_err("cannot register PPS source \"%s\"\n", info.path);
+ return ret;
+ }
+ tty->disc_data = (void *) ret;
+
+ /* Should open N_TTY ldisc too */
+ ret = n_tty_open(tty);
+ if (ret < 0)
+ pps_unregister_source((int) tty->disc_data);
+
+ pr_info("PPS source #%d \"%s\" added\n", ret, info.path);
+
+ return 0;
+}
+
+static void pps_tty_close(struct tty_struct *tty)
+{
+ int id = (int) tty->disc_data;
+
+ pps_unregister_source(id);
+ n_tty_close(tty);
+
+ pr_info("PPS source #%d removed\n", id);
+}
+
+struct tty_ldisc pps_ldisc = {
+ .magic = PPS_TTY_MAGIC,
+ .name = "pps_tty",
+ .dcd_change = pps_tty_dcd_change,
+ .open = pps_tty_open,
+ .close = pps_tty_close,
+
+ /* Now we should use N_TTY ldisc methods in order to have
+ * normal tty behaviour
+ */
+ .flush_buffer = n_tty_flush_buffer,
+ .chars_in_buffer = n_tty_chars_in_buffer,
+ .read = n_tty_read,
+ .write = n_tty_write,
+ .ioctl = n_tty_ioctl,
+ .set_termios = n_tty_set_termios,
+ .poll = n_tty_poll,
+ .receive_buf = n_tty_receive_buf,
+ .write_wakeup = n_tty_write_wakeup
+};
+
+/*
+ * Module stuff
+ */
+
+static int __init pps_tty_init(void)
+{
+ int err;
+
+ err = tty_register_ldisc(N_PPS, &pps_ldisc);
+ if (err)
+ pr_err("can't register PPS line discipline\n");
+ else
+ pr_info("PPS line discipline registered\n");
+
+ return err;
+}
+
+static void __exit pps_tty_cleanup(void)
+{
+ int err;
+
+ err = tty_unregister_ldisc(N_PPS);
+ if (err)
+ pr_err("can't unregister PPS line discipline\n");
+ else
+ pr_info("PPS line discipline removed\n");
+}
+
+module_init(pps_tty_init);
+module_exit(pps_tty_cleanup);
+
+MODULE_ALIAS_LDISC(N_PPS);
+MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
+MODULE_DESCRIPTION("PPS TTY device driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 4368a13..7e73c45 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -33,7 +33,6 @@
#include <linux/serial.h> /* for serial_state and serial_icounter_struct */
#include <linux/delay.h>
#include <linux/mutex.h>
-#include <linux/pps.h>

#include <asm/irq.h>
#include <asm/uaccess.h>
@@ -634,63 +633,6 @@ static int uart_get_info(struct uart_state *state,
return 0;
}

-#ifdef CONFIG_PPS_CLIENT_UART
-
-static int
-uart_register_pps_port(struct uart_state *state, struct uart_port *port)
-{
- struct tty_driver *drv = port->info->tty->driver;
- int ret;
-
- state->pps_info.owner = THIS_MODULE;
- state->pps_info.dev = port->dev;
- snprintf(state->pps_info.name, PPS_MAX_NAME_LEN, "%s%d",
- drv->driver_name, port->line);
- snprintf(state->pps_info.path, PPS_MAX_NAME_LEN, "/dev/%s%d",
- drv->name, port->line);
-
- state->pps_info.mode = PPS_CAPTUREBOTH | \
- PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
- PPS_CANWAIT | PPS_TSFMT_TSPEC;
-
- ret = pps_register_source(&state->pps_info, PPS_CAPTUREBOTH | \
- PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
- if (ret < 0) {
- dev_err(port->dev, "cannot register PPS source \"%s\"\n",
- state->pps_info.path);
- return ret;
- }
- port->pps_source = ret;
- dev_dbg(port->dev, "PPS source #%d \"%s\" added\n",
- port->pps_source, state->pps_info.path);
-
- return 0;
-}
-
-static void
-uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
-{
- pps_unregister_source(port->pps_source);
- dev_dbg(port->dev, "PPS source #%d \"%s\" removed\n",
- port->pps_source, state->pps_info.path);
-}
-
-#else
-
-static inline int
-uart_register_pps_port(struct uart_state *state, struct uart_port *port)
-{
- return 0;
-}
-
-static inline void
-uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
-{
- /* Nop */
-}
-
-#endif /* CONFIG_PPS_CLIENT_UART */
-
static int uart_set_info(struct uart_state *state,
struct serial_struct __user *newinfo)
{
@@ -865,14 +807,6 @@ static int uart_set_info(struct uart_state *state,
(port->flags & UPF_LOW_LATENCY) ? 1 : 0;

check_and_exit:
- /* PPS support enabled/disabled? */
- if ((old_flags & UPF_HARDPPS_CD) != (new_flags & UPF_HARDPPS_CD)) {
- if (new_flags & UPF_HARDPPS_CD)
- uart_register_pps_port(state, port);
- else
- uart_unregister_pps_port(state, port);
- }
-
retval = 0;
if (port->type == PORT_UNKNOWN)
goto exit;
@@ -2206,12 +2140,6 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
port->ops->config_port(port, flags);
}

- /*
- * Add the PPS support for the current port.
- */
- if (port->flags & UPF_HARDPPS_CD)
- uart_register_pps_port(state, port);
-
if (port->type != PORT_UNKNOWN) {
unsigned long flags;

@@ -2468,12 +2396,6 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *port)
mutex_unlock(&state->mutex);

/*
- * Remove PPS support from the current port.
- */
- if (port->flags & UPF_HARDPPS_CD)
- uart_unregister_pps_port(state, port);
-
- /*
* Remove the devices from the tty layer
*/
tty_unregister_device(drv->tty_driver, port->line);
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index a80d1ea..80f85fc 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -240,9 +240,6 @@ struct uart_port {
unsigned char regshift; /* reg offset shift */
unsigned char iotype; /* io access style */
unsigned char unused1;
-#ifdef CONFIG_PPS_CLIENT_UART
- int pps_source; /* PPS source ID */
-#endif

#define UPIO_PORT (0)
#define UPIO_HUB6 (1)
@@ -321,10 +318,6 @@ struct uart_state {
struct uart_info *info;
struct uart_port *port;

-#ifdef CONFIG_PPS_CLIENT_UART
- struct pps_source_info pps_info;
-#endif
-
struct mutex mutex;
};

@@ -488,31 +481,11 @@ static inline void
uart_handle_dcd_change(struct uart_port *port, unsigned int status)
{
struct uart_info *info = port->info;
+ struct tty_ldisc *ld = tty_ldisc_ref(info->tty);
+ struct timespec ts;

-#ifdef CONFIG_PPS_CLIENT_UART
- struct timespec __ts;
- struct pps_ktime ts;
-
- /* First of all we get the time stamp... */
- getnstimeofday(&__ts);
-
- /* ... and translate it to PPS time data struct */
- ts.sec = __ts.tv_sec;
- ts.nsec = __ts.tv_nsec;
-
- if (port->flags & UPF_HARDPPS_CD) {
- pps_event(port->pps_source,
-#ifdef CONFIG_PPS_IRQ_EVENTS
- &pps_irq_ts[port->irq],
-#else
- &ts,
-#endif
- status ? PPS_CAPTUREASSERT : PPS_CAPTURECLEAR,
- port);
- dev_dbg(port->dev, "PPS %s at %lu on source #%d\n",
- status ? "assert" : "clear", jiffies, port->pps_source);
- }
-#endif
+ if (ld->dcd_change)
+ getnstimeofday(&ts);

port->icount.dcd++;

@@ -522,6 +495,10 @@ uart_handle_dcd_change(struct uart_port *port, unsigned int status)
else if (info->tty)
tty_hangup(info->tty);
}
+
+ if (ld->dcd_change)
+ ld->dcd_change(port, status, &ts);
+ tty_ldisc_deref(ld);
}

/**
--
1.5.4.3


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