[PATCH 5/7] PPS: serial clients support.

From: Rodolfo Giometti
Date: Thu Apr 10 2008 - 11:17:42 EST

Adds support for the PPS sources connected with the CD (Carrier
Detect) pin of a serial port.

Signed-off-by: Rodolfo Giometti <giometti@xxxxxxxx>
---
drivers/pps/clients/Kconfig | 10 +++
drivers/serial/8250.c | 2 +
drivers/serial/serial_core.c | 131 ++++++++++++++++++++++++++++++++----------
include/linux/serial_core.h | 30 ++++++++--
4 files changed, 136 insertions(+), 37 deletions(-)

diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig
index 60b83be..517c338 100644
--- a/drivers/pps/clients/Kconfig
+++ b/drivers/pps/clients/Kconfig
@@ -15,4 +15,14 @@ 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)
+ help
+ If you say yes here you get support for a PPS source connected
+ with the CD (Carrier Detect) pin of your serial port.
+
endif
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 77f7a7f..880cbeb 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -2119,6 +2119,8 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
up->ier |= UART_IER_MSI;
if (up->capabilities & UART_CAP_UUE)
up->ier |= UART_IER_UUE | UART_IER_RTOIE;
+ if (up->port.flags & UPF_HARDPPS_CD)
+ up->ier |= UART_IER_MSI; /* enable interrupts */

serial_out(up, UART_IER, up->ier);

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 0f5a179..5a97e63 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -33,6 +33,7 @@
#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>
@@ -58,8 +59,7 @@ static struct lock_class_key port_lock_key;
#define uart_console(port) (0)
#endif

-static void uart_change_speed(struct uart_state *state,
- struct ktermios *old_termios);
+static void uart_change_speed(struct uart_state *state, struct ktermios *old_termios);
static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
static void uart_change_pm(struct uart_state *state, int pm_state);

@@ -130,8 +130,8 @@ uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
spin_unlock_irqrestore(&port->lock, flags);
}

-#define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
-#define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
+#define uart_set_mctrl(port,set) uart_update_mctrl(port,set,0)
+#define uart_clear_mctrl(port,clear) uart_update_mctrl(port,0,clear)

/*
* Startup the port. This will be called once per open. All calls
@@ -291,7 +291,7 @@ uart_update_timeout(struct uart_port *port, unsigned int cflag,
break;
default:
bits = 10;
- break; /* CS8 */
+ break; // CS8
}

if (cflag & CSTOPB)
@@ -372,8 +372,7 @@ uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
*/
termios->c_cflag &= ~CBAUD;
if (old) {
- baud = tty_termios_baud_rate(old);
- tty_termios_encode_baud_rate(termios, baud, baud);
+ termios->c_cflag |= old->c_cflag & CBAUD;
old = NULL;
continue;
}
@@ -382,7 +381,7 @@ uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
* As a last resort, if the quotient is zero,
* default to 9600 bps
*/
- tty_termios_encode_baud_rate(termios, 9600, 9600);
+ termios->c_cflag |= B9600;
}

return 0;
@@ -635,6 +634,63 @@ 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)
{
@@ -789,8 +845,7 @@ static int uart_set_info(struct uart_state *state,
* We failed anyway.
*/
retval = -EBUSY;
- /* Added to return the correct error -Ram Gupta */
- goto exit;
+ goto exit; // Added to return the correct error -Ram Gupta
}
}

@@ -810,11 +865,19 @@ 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;
if (state->info->flags & UIF_INITIALIZED) {
- if (((old_flags ^ port->flags) & UPF_SPD_MASK) ||
+ if (((old_flags ^ port->flags) & (UPF_SPD_MASK|UPF_HARDPPS_CD)) ||
old_custom_divisor != port->custom_divisor) {
/*
* If they're setting up a custom divisor or speed,
@@ -1139,8 +1202,7 @@ uart_ioctl(struct tty_struct *tty, struct file *filp, unsigned int cmd,
return ret;
}

-static void uart_set_termios(struct tty_struct *tty,
- struct ktermios *old_termios)
+static void uart_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
{
struct uart_state *state = tty->driver_data;
unsigned long flags;
@@ -1464,8 +1526,9 @@ uart_block_til_ready(struct file *filp, struct uart_state *state)
*/
if ((filp->f_flags & O_NONBLOCK) ||
(info->tty->termios->c_cflag & CLOCAL) ||
- (info->tty->flags & (1 << TTY_IO_ERROR)))
+ (info->tty->flags & (1 << TTY_IO_ERROR))) {
break;
+ }

/*
* Set DTR to allow modem to know we're waiting. Do
@@ -1553,8 +1616,8 @@ static struct uart_state *uart_get(struct uart_driver *drv, int line)
}

/*
- * calls to uart_open are serialised by the BKL in
- * fs/char_dev.c:chrdev_open()
+ * In 2.4.5, calls to uart_open are serialised by the BKL in
+ * linux/fs/devices.c:chrdev_open()
* Note that if this fails, then uart_close() _will_ be called.
*
* In time, we want to scrap the "opening nonpresent ports"
@@ -1684,7 +1747,8 @@ static int uart_line_info(char *buf, struct uart_driver *drv, int i)
return ret + 1;
}

- if (capable(CAP_SYS_ADMIN)) {
+ if(capable(CAP_SYS_ADMIN))
+ {
mutex_lock(&state->mutex);
pm_state = state->pm_state;
if (pm_state)
@@ -1711,11 +1775,11 @@ static int uart_line_info(char *buf, struct uart_driver *drv, int i)
ret += sprintf(buf + ret, " oe:%d",
port->icount.overrun);

-#define INFOBIT(bit, str) \
+#define INFOBIT(bit,str) \
if (port->mctrl & (bit)) \
strncat(stat_buf, (str), sizeof(stat_buf) - \
strlen(stat_buf) - 2)
-#define STATBIT(bit, str) \
+#define STATBIT(bit,str) \
if (status & (bit)) \
strncat(stat_buf, (str), sizeof(stat_buf) - \
strlen(stat_buf) - 2)
@@ -1979,7 +2043,6 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)

if (state->info && state->info->flags & UIF_INITIALIZED) {
const struct uart_ops *ops = port->ops;
- int tries;

state->info->flags = (state->info->flags & ~UIF_INITIALIZED)
| UIF_SUSPENDED;
@@ -1993,14 +2056,9 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
/*
* Wait for the transmitter to empty.
*/
- for (tries = 3; !ops->tx_empty(port) && tries; tries--)
+ while (!ops->tx_empty(port)) {
msleep(10);
- if (!tries)
- printk(KERN_ERR "%s%s%s%d: Unable to drain "
- "transmitter\n",
- port->dev ? port->dev->bus_id : "",
- port->dev ? ": " : "",
- drv->dev_name, port->line);
+ }

ops->shutdown(port);
}
@@ -2037,6 +2095,8 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
}
port->suspended = 0;

+ uart_change_pm(state, 0);
+
/*
* Re-enable the console device after suspending.
*/
@@ -2055,7 +2115,6 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
if (state->info && state->info->tty && termios.c_cflag == 0)
termios = *state->info->tty->termios;

- uart_change_pm(state, 0);
port->ops->set_termios(port, &termios, NULL);
console_start(port->cons);
}
@@ -2064,7 +2123,6 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
const struct uart_ops *ops = port->ops;
int ret;

- uart_change_pm(state, 0);
ops->set_mctrl(port, 0);
ret = ops->startup(port);
if (ret == 0) {
@@ -2148,6 +2206,12 @@ 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;

@@ -2158,11 +2222,10 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,

/*
* Ensure that the modem control lines are de-activated.
- * keep the DTR setting that is set in uart_set_options()
* We probably don't need a spinlock around this, but
*/
spin_lock_irqsave(&port->lock, flags);
- port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
+ port->ops->set_mctrl(port, 0);
spin_unlock_irqrestore(&port->lock, flags);

/*
@@ -2405,6 +2468,12 @@ 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 289942f..0f8fbd4 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -166,6 +166,7 @@
#include <linux/tty.h>
#include <linux/mutex.h>
#include <linux/sysrq.h>
+#include <linux/pps.h>

struct uart_port;
struct uart_info;
@@ -245,6 +246,9 @@ 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)
@@ -289,7 +293,8 @@ struct uart_port {
#define UPF_IOREMAP ((__force upf_t) (1 << 31))

#define UPF_CHANGE_MASK ((__force upf_t) (0x17fff))
-#define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
+#define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY\
+ |UPF_HARDPPS_CD))

unsigned int mctrl; /* current modem ctrl settings */
unsigned int timeout; /* character-based timeout */
@@ -322,6 +327,10 @@ 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;
};

@@ -486,13 +495,22 @@ uart_handle_dcd_change(struct uart_port *port, unsigned int status)
{
struct uart_info *info = port->info;

- port->icount.dcd++;
-
-#ifdef CONFIG_HARD_PPS
- if ((port->flags & UPF_HARDPPS_CD) && status)
- hardpps();
+#ifdef CONFIG_PPS_CLIENT_UART
+ if (port->flags & UPF_HARDPPS_CD) {
+ if (status) {
+ pps_event(port->pps_source, PPS_CAPTUREASSERT, port);
+ dev_dbg(port->dev, "PPS assert at %lu on source #%d\n",
+ jiffies, port->pps_source);
+ } else {
+ pps_event(port->pps_source, PPS_CAPTURECLEAR, port);
+ dev_dbg(port->dev, "PPS clear at %lu on source #%d\n",
+ jiffies, port->pps_source);
+ }
+ }
#endif

+ port->icount.dcd++;
+
if (info->flags & UIF_CHECK_CD) {
if (status)
wake_up_interruptible(&info->open_wait);
--
1.5.4.3

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