[PATCH RFC net-next v1 1/9] ptp: introduce programmable pins.

From: Richard Cochran
Date: Sat Mar 08 2014 - 14:44:08 EST

This patch adds a pair of new ioctls to the PTP Hardware Clock device
interface. Using the ioctls, user space programs can query each pin to
find out its current function and also reprogram a different function
if desired.

Signed-off-by: Richard Cochran <richardcochran@xxxxxxxxx>
---
drivers/ptp/ptp_chardev.c | 133 +++++++++++++++++++++++++++++++++++++-
drivers/ptp/ptp_clock.c | 23 +++++++
drivers/ptp/ptp_private.h | 4 ++
include/linux/ptp_clock_kernel.h | 33 ++++++++++
include/uapi/linux/ptp_clock.h | 39 ++++++++++-
5 files changed, 230 insertions(+), 2 deletions(-)

diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index 34a0c60..dc13d1e 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -25,6 +25,104 @@

#include "ptp_private.h"

+static int ptp_disable_pinfunc(struct ptp_clock_info *ops,
+ enum ptp_pin_function func, unsigned int chan)
+{
+ struct ptp_clock_request rq;
+ int err = 0;
+
+ memset(&rq, 0, sizeof(rq));
+
+ switch (func) {
+ case PTP_PF_NONE:
+ break;
+ case PTP_PF_EXTTS:
+ rq.type = PTP_CLK_REQ_EXTTS;
+ rq.extts.index = chan;
+ err = ops->enable(ops, &rq, 0);
+ break;
+ case PTP_PF_PEROUT:
+ rq.type = PTP_CLK_REQ_PEROUT;
+ rq.perout.index = chan;
+ err = ops->enable(ops, &rq, 0);
+ break;
+ case PTP_PF_PHYSYNC:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return err;
+}
+
+int ptp_setpin(struct ptp_clock *ptp, unsigned int pin,
+ enum ptp_pin_function func, unsigned int chan)
+{
+ struct ptp_clock_info *info = ptp->info;
+ struct ptp_pin_desc *pin1 = NULL, *pin2 = &info->pin_config[pin];
+ unsigned int i;
+
+ /* Check to see if any other pin previously had this function. */
+ if (mutex_lock_interruptible(&ptp->pincfg_mux))
+ return -ERESTARTSYS;
+ for (i = 0; i < info->n_pins; i++) {
+ if (info->pin_config[i].func == func &&
+ info->pin_config[i].chan == chan) {
+ pin1 = &info->pin_config[i];
+ break;
+ }
+ }
+ mutex_unlock(&ptp->pincfg_mux);
+ if (pin1 && i == pin)
+ return 0;
+
+ /* Check the desired function and channel. */
+ switch (func) {
+ case PTP_PF_NONE:
+ break;
+ case PTP_PF_EXTTS:
+ if (chan >= info->n_ext_ts)
+ return -EINVAL;
+ break;
+ case PTP_PF_PEROUT:
+ if (chan >= info->n_per_out)
+ return -EINVAL;
+ break;
+ case PTP_PF_PHYSYNC:
+ pr_err("sorry, cannot reassign the calibration pin\n");
+ return -EINVAL;
+ default:
+ return -EINVAL;
+ }
+
+ if (pin1 && pin1->func == PTP_PF_PHYSYNC) {
+ pr_err("sorry, cannot reprogram the calibration pin\n");
+ return -EINVAL;
+ }
+
+ if (info->setpin(info, pin, func, chan)) {
+ pr_err("driver cannot use function %u on pin %u\n", func, chan);
+ return -EOPNOTSUPP;
+ }
+
+ /* Disable whatever function was previously assigned. */
+ ptp_disable_pinfunc(info, pin2->func, pin2->chan);
+ if (pin1)
+ ptp_disable_pinfunc(info, func, chan);
+
+ if (mutex_lock_interruptible(&ptp->pincfg_mux))
+ return -ERESTARTSYS;
+ pin2->func = func;
+ pin2->chan = chan;
+ if (pin1) {
+ pin1->func = PTP_PF_NONE;
+ pin1->chan = 0;
+ }
+ mutex_unlock(&ptp->pincfg_mux);
+
+ return 0;
+}
+
int ptp_open(struct posix_clock *pc, fmode_t fmode)
{
return 0;
@@ -35,12 +133,13 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
struct ptp_clock_caps caps;
struct ptp_clock_request req;
struct ptp_sys_offset *sysoff = NULL;
+ struct ptp_pin_desc pd;
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
struct ptp_clock_info *ops = ptp->info;
struct ptp_clock_time *pct;
struct timespec ts;
int enable, err = 0;
- unsigned int i;
+ unsigned int i, pin_index;

switch (cmd) {

@@ -51,6 +150,7 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
caps.n_ext_ts = ptp->info->n_ext_ts;
caps.n_per_out = ptp->info->n_per_out;
caps.pps = ptp->info->pps;
+ caps.n_pins = ptp->info->n_pins;
if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))
err = -EFAULT;
break;
@@ -126,6 +226,37 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
err = -EFAULT;
break;

+ case PTP_PIN_GETFUNC:
+ if (copy_from_user(&pd, (void __user *)arg, sizeof(pd))) {
+ err = -EFAULT;
+ break;
+ }
+ pin_index = pd.index;
+ if (pin_index >= ops->n_pins) {
+ err = -EINVAL;
+ break;
+ }
+ if (mutex_lock_interruptible(&ptp->pincfg_mux))
+ return -ERESTARTSYS;
+ pd = ops->pin_config[pin_index];
+ mutex_unlock(&ptp->pincfg_mux);
+ if (!err && copy_to_user((void __user *)arg, &pd, sizeof(pd)))
+ err = -EFAULT;
+ break;
+
+ case PTP_PIN_SETFUNC:
+ if (copy_from_user(&pd, (void __user *)arg, sizeof(pd))) {
+ err = -EFAULT;
+ break;
+ }
+ pin_index = pd.index;
+ if (pin_index >= ops->n_pins) {
+ err = -EINVAL;
+ break;
+ }
+ err = ptp_setpin(ptp, pin_index, pd.func, pd.chan);
+ break;
+
default:
err = -ENOTTY;
break;
diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index a8319b2..3105d1d 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -169,6 +169,7 @@ static void delete_ptp_clock(struct posix_clock *pc)
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);

mutex_destroy(&ptp->tsevq_mux);
+ mutex_destroy(&ptp->pincfg_mux);
ida_simple_remove(&ptp_clocks_map, ptp->index);
kfree(ptp);
}
@@ -203,6 +204,7 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
ptp->index = index;
spin_lock_init(&ptp->tsevq.lock);
mutex_init(&ptp->tsevq_mux);
+ mutex_init(&ptp->pincfg_mux);
init_waitqueue_head(&ptp->tsev_wq);

/* Create a new device in our class. */
@@ -249,6 +251,7 @@ no_sysfs:
device_destroy(ptp_class, ptp->devid);
no_device:
mutex_destroy(&ptp->tsevq_mux);
+ mutex_destroy(&ptp->pincfg_mux);
no_slot:
kfree(ptp);
no_memory:
@@ -305,6 +308,26 @@ int ptp_clock_index(struct ptp_clock *ptp)
}
EXPORT_SYMBOL(ptp_clock_index);

+int ptp_find_pin(struct ptp_clock *ptp,
+ enum ptp_pin_function func, unsigned int chan)
+{
+ struct ptp_pin_desc *pin = NULL;
+ int i;
+
+ mutex_lock(&ptp->pincfg_mux);
+ for (i = 0; i < ptp->info->n_pins; i++) {
+ if (ptp->info->pin_config[i].func == func &&
+ ptp->info->pin_config[i].chan == chan) {
+ pin = &ptp->info->pin_config[i];
+ break;
+ }
+ }
+ mutex_unlock(&ptp->pincfg_mux);
+
+ return pin ? pin - ptp->info->pin_config : -1;
+}
+EXPORT_SYMBOL(ptp_find_pin);
+
/* module operations */

static void __exit ptp_exit(void)
diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h
index df03f2e..253e942 100644
--- a/drivers/ptp/ptp_private.h
+++ b/drivers/ptp/ptp_private.h
@@ -48,6 +48,7 @@ struct ptp_clock {
long dialed_frequency; /* remembers the frequency adjustment */
struct timestamp_event_queue tsevq; /* simple fifo for time stamps */
struct mutex tsevq_mux; /* one process at a time reading the fifo */
+ struct mutex pincfg_mux; /* protect concurrent info->pin_config access */
wait_queue_head_t tsev_wq;
int defunct; /* tells readers to go away when clock is being removed */
};
@@ -69,6 +70,9 @@ static inline int queue_cnt(struct timestamp_event_queue *q)
* see ptp_chardev.c
*/

+int ptp_setpin(struct ptp_clock *ptp, unsigned int pin,
+ enum ptp_pin_function func, unsigned int chan);
+
long ptp_ioctl(struct posix_clock *pc,
unsigned int cmd, unsigned long arg);

diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index 38a9935..04b0d42 100644
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -49,7 +49,11 @@ struct ptp_clock_request {
* @n_alarm: The number of programmable alarms.
* @n_ext_ts: The number of external time stamp channels.
* @n_per_out: The number of programmable periodic signals.
+ * @n_pins: The number of programmable pins.
* @pps: Indicates whether the clock supports a PPS callback.
+ * @pin_config: Array of length 'n_pins'. If the number of
+ * programmable pins is nonzero, then drivers must
+ * allocate and initialize this array.
*
* clock operations
*
@@ -70,6 +74,18 @@ struct ptp_clock_request {
* parameter request: Desired resource to enable or disable.
* parameter on: Caller passes one to enable or zero to disable.
*
+ * @setpin: Confirm that a pin can perform a given function. The PTP
+ * Hardware Clock subsystem maintains the 'pin_config'
+ * array on behalf of the drivers, but the PHC subsystem
+ * assumes that every pin can perform every function. This
+ * hook gives drivers a way of telling the core about
+ * limitations on specific pins. This function must return
+ * zero if the function can be assigned to this pin, and
+ * nonzero otherwise.
+ * parameter pin: index of the pin in question.
+ * parameter func: the desired function to use.
+ * parameter chan: the function channel index to use.
+ *
* Drivers should embed their ptp_clock_info within a private
* structure, obtaining a reference to it using container_of().
*
@@ -83,13 +99,17 @@ struct ptp_clock_info {
int n_alarm;
int n_ext_ts;
int n_per_out;
+ int n_pins;
int pps;
+ struct ptp_pin_desc *pin_config;
int (*adjfreq)(struct ptp_clock_info *ptp, s32 delta);
int (*adjtime)(struct ptp_clock_info *ptp, s64 delta);
int (*gettime)(struct ptp_clock_info *ptp, struct timespec *ts);
int (*settime)(struct ptp_clock_info *ptp, const struct timespec *ts);
int (*enable)(struct ptp_clock_info *ptp,
struct ptp_clock_request *request, int on);
+ int (*setpin)(struct ptp_clock_info *ptp, unsigned int pin,
+ enum ptp_pin_function func, unsigned int chan);
};

struct ptp_clock;
@@ -156,4 +176,17 @@ extern void ptp_clock_event(struct ptp_clock *ptp,

extern int ptp_clock_index(struct ptp_clock *ptp);

+/**
+ * ptp_find_pin() - obtain the pin index of a given auxiliary function
+ *
+ * @ptp: The clock obtained from ptp_clock_register().
+ * @func: One of the ptp_pin_function enumerated values.
+ * @chan: The particular functional channel to find.
+ * Return: Pin index in the range of zero to ptp_clock_caps.n_pins - 1,
+ * or -1 if the auxiliary function cannot be found.
+ */
+
+int ptp_find_pin(struct ptp_clock *ptp,
+ enum ptp_pin_function func, unsigned int chan);
+
#endif
diff --git a/include/uapi/linux/ptp_clock.h b/include/uapi/linux/ptp_clock.h
index b65c834..f0b7bfe 100644
--- a/include/uapi/linux/ptp_clock.h
+++ b/include/uapi/linux/ptp_clock.h
@@ -50,7 +50,8 @@ struct ptp_clock_caps {
int n_ext_ts; /* Number of external time stamp channels. */
int n_per_out; /* Number of programmable periodic signals. */
int pps; /* Whether the clock supports a PPS callback. */
- int rsv[15]; /* Reserved for future use. */
+ int n_pins; /* Number of input/output pins. */
+ int rsv[14]; /* Reserved for future use. */
};

struct ptp_extts_request {
@@ -80,6 +81,40 @@ struct ptp_sys_offset {
struct ptp_clock_time ts[2 * PTP_MAX_SAMPLES + 1];
};

+enum ptp_pin_function {
+ PTP_PF_NONE,
+ PTP_PF_EXTTS,
+ PTP_PF_PEROUT,
+ PTP_PF_PHYSYNC,
+};
+
+struct ptp_pin_desc {
+ /*
+ * Hardware specific human readable pin name. This field is
+ * set by the kernel during the PTP_PIN_GETFUNC ioctl and is
+ * ignored for the PTP_PIN_SETFUNC ioctl.
+ */
+ char name[64];
+ /*
+ * Pin index in the range of zero to ptp_clock_caps.n_pins - 1.
+ */
+ unsigned int index;
+ /*
+ * Which of the PTP_PF_xxx functions to use on this pin.
+ */
+ unsigned int func;
+ /*
+ * The specific channel to use for this function.
+ * This corresponds to the 'index' field of the
+ * PTP_EXTTS_REQUEST and PTP_PEROUT_REQUEST ioctls.
+ */
+ unsigned int chan;
+ /*
+ * Reserved for future use.
+ */
+ unsigned int rsv[5];
+};
+
#define PTP_CLK_MAGIC '='

#define PTP_CLOCK_GETCAPS _IOR(PTP_CLK_MAGIC, 1, struct ptp_clock_caps)
@@ -87,6 +122,8 @@ struct ptp_sys_offset {
#define PTP_PEROUT_REQUEST _IOW(PTP_CLK_MAGIC, 3, struct ptp_perout_request)
#define PTP_ENABLE_PPS _IOW(PTP_CLK_MAGIC, 4, int)
#define PTP_SYS_OFFSET _IOW(PTP_CLK_MAGIC, 5, struct ptp_sys_offset)
+#define PTP_PIN_GETFUNC _IOWR(PTP_CLK_MAGIC, 6, struct ptp_pin_desc)
+#define PTP_PIN_SETFUNC _IOW(PTP_CLK_MAGIC, 7, struct ptp_pin_desc)

struct ptp_extts_event {
struct ptp_clock_time t; /* Time event occured. */
--
1.7.10.4

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