[LinuxPPS] [pre-PATCH] PPS line discipline support
Rodolfo Giometti
giometti at enneenne.com
Sun Jun 1 16:01:19 CEST 2008
Hello,
here I attach a pre-patch which should implement what asked by
kernel's gurus: a PPS line discipline.
I have no hardware to test it (donations are welcomed ;) so you should
test it by yourself. Sorry.
The patch applies to the *latest* GIT repository. After patching the
kernel you should enable the new PPS line discipline into your kernel
configuration and then install it.
Please, note that the line discipline *replaces* the UART PPS support!
To enable the line discipline (and then got a new PPS source) you can
use my (little) tool ttyctrl at
http://ftp.enneenne.com/pub/misc/linuxpps/tools/ publish in both
binary and source. Just use the command:
$ ttyctrl -X -s 17 <serial_device>
put at <serial_device> the file /dev/ttyS0, /dev/ttyS1 or whatever
suites your needs.
If everything goes well you should see a new pps source into the
/sys/class/pps/ directory and you NTPD should wrok as before.
You should test both standard IRQ support and CONFIG_PPS_IRQ_EVENTS
and report differences.
Please, report your results *on this list* so that all people reading
may look and contribute!
After positive feedbacks I'll repropose LinuxPPS to the kernel
guru's. :)
Ciao,
Rodolfo
--
GNU/Linux Solutions e-mail: giometti at enneenne.com
Linux Device Driver giometti at linux.it
Embedded Systems phone: +39 349 2432127
UNIX programming skype: rodolfo.giometti
-------------- next part --------------
diff --git a/Documentation/tty.txt b/Documentation/tty.txt
index 8e65c44..8589f72 100644
--- a/Documentation/tty.txt
+++ b/Documentation/tty.txt
@@ -100,6 +100,8 @@ write_wakeup() - May be called at any point between open and close.
is permitted to call the driver write method from
this function. In such a situation defer it.
+dcd_change() - Report to the tty line the current DCD pin status changes.
+
Driver Access
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..5ad888c
--- /dev/null
+++ b/drivers/pps/clients/pps-ldisc.c
@@ -0,0 +1,147 @@
+/*
+ * pps-ldisc.c -- PPS line discipline
+ *
+ *
+ * Copyright (C) 2008 Rodolfo Giometti <giometti at 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/tty.h>
+#include <linux/pps.h>
+
+#define PPS_TTY_MAGIC 0x0001
+
+#ifdef CONFIG_PPS_IRQ_EVENTS
+
+static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int irq,
+ unsigned int status)
+{
+ int id = (int) tty->disc_data;
+
+ pps_event(id, &pps_irq_ts[irq],
+ status ? PPS_CAPTUREASSERT : PPS_CAPTURECLEAR, tty);
+
+ pr_debug("[IRQev] PPS %s at %lu on source #%d\n",
+ status ? "assert" : "clear", jiffies, id);
+}
+
+#else
+
+static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int irq,
+ unsigned int status)
+{
+ int id = (int) tty->disc_data;
+ 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;
+
+ /* Now do the PPS event report */
+ pps_event(id, &ts,
+ status ? PPS_CAPTUREASSERT : PPS_CAPTURECLEAR, tty);
+
+ 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;
+ 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;
+
+ pr_info("PPS source #%d removed\n", id);
+ pps_unregister_source(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,
+ .owner = THIS_MODULE,
+};
+
+/*
+ * 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");
+
+ 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");
+ }
+
+ pr_info("PPS line discipline removed\n");
+}
+
+module_init(pps_tty_init);
+module_exit(pps_tty_cleanup);
+
+MODULE_AUTHOR("Rodolfo Giometti <giometti at linux.it>");
+MODULE_DESCRIPTION("PPS TTY device driver");
+MODULE_ALIAS_LDISC(N_PPS);
+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..0813af4 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 +481,12 @@ 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);
-#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);
+ if (ld->dcd_change) {
+ ld->dcd_change(info->tty, port->irq, status);
+ tty_ldisc_deref(ld);
}
-#endif
port->icount.dcd++;
diff --git a/include/linux/tty.h b/include/linux/tty.h
index defd2ab..fc1c685 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -23,7 +23,7 @@
*/
#define NR_UNIX98_PTY_DEFAULT 4096 /* Default maximum for Unix98 ptys */
#define NR_UNIX98_PTY_MAX (1 << MINORBITS) /* Absolute limit */
-#define NR_LDISCS 17
+#define NR_LDISCS 18
/* line disciplines */
#define N_TTY 0
@@ -44,6 +44,7 @@
#define N_SYNC_PPP 14 /* synchronous PPP */
#define N_HCI 15 /* Bluetooth HCI UART */
#define N_GIGASET_M101 16 /* Siemens Gigaset M101 serial DECT adapter */
+#define N_PPS 17 /* Pulse per Second */
/*
* This character is the same as _POSIX_VDISABLE: it cannot be used as
diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h
index 6226504..6378d39 100644
--- a/include/linux/tty_ldisc.h
+++ b/include/linux/tty_ldisc.h
@@ -99,6 +99,10 @@
* cease I/O to the tty driver. Can sleep. The driver should
* seek to perform this action quickly but should wait until
* any pending driver I/O is completed.
+ *
+ * void (*dcd_change)(struct tty_struct *, unsigned int, unsigned int)
+ *
+ * Tells the discipline that the DCD pin has changed its status.
*/
#include <linux/fs.h>
@@ -136,6 +140,7 @@ struct tty_ldisc {
void (*receive_buf)(struct tty_struct *, const unsigned char *cp,
char *fp, int count);
void (*write_wakeup)(struct tty_struct *);
+ void (*dcd_change)(struct tty_struct *, unsigned int, unsigned int);
struct module *owner;
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