Merge branch 'ptp-adjphase-cleanups'

Rahul Rameshbabu says:

====================
ptp .adjphase cleanups

The goal of this patch series is to improve documentation of .adjphase, add
a new callback .getmaxphase to enable advertising the max phase offset a
device PHC can support, and support invoking .adjphase from the testptp
kselftest.

Changes:
  v2->v1:
    * Removes arbitrary rule that the PHC servo must restore the frequency
      to the value used in the last .adjfine call if any other PHC
      operation is used after a .adjphase operation.
    * Removes a macro introduced in v1 for adding PTP sysfs device
      attribute nodes using a callback for populating the data.

Link: https://lore.kernel.org/netdev/20230120160609.19160723@kernel.org/
Link: https://lore.kernel.org/netdev/20230510205306.136766-1-rrameshbabu@nvidia.com/
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/driver-api/ptp.rst

@@ -73,6 +73,22 @@ Writing clock drivers
    class driver, since the lock may also be needed by the clock
    driver's interrupt service routine.
 
+PTP hardware clock requirements for '.adjphase'
+-----------------------------------------------
+
+   The 'struct ptp_clock_info' interface has a '.adjphase' function.
+   This function has a set of requirements from the PHC in order to be
+   implemented.
+
+     * The PHC implements a servo algorithm internally that is used to
+       correct the offset passed in the '.adjphase' call.
+     * When other PTP adjustment functions are called, the PHC servo
+       algorithm is disabled.
+
+   **NOTE:** '.adjphase' is not a simple time adjustment functionality
+   that 'jumps' the PHC clock time based on the provided offset. It
+   should correct the offset provided using an internal algorithm.
+
 Supported hardware
 ==================
 
@@ -106,3 +122,16 @@ Supported hardware
           - LPF settings (bandwidth, phase limiting, automatic holdover, physical layer assist (per ITU-T G.8273.2))
           - Programmable output PTP clocks, any frequency up to 1GHz (to other PHY/MAC time stampers, refclk to ASSPs/SoCs/FPGAs)
           - Lock to GNSS input, automatic switching between GNSS and user-space PHC control (optional)
+
+   * NVIDIA Mellanox
+
+     - GPIO
+          - Certain variants of ConnectX-6 Dx and later products support one
+            GPIO which can time stamp external triggers and one GPIO to produce
+            periodic signals.
+          - Certain variants of ConnectX-5 and older products support one GPIO,
+            configured to either time stamp external triggers or produce
+            periodic signals.
+     - PHC instances
+          - All ConnectX devices have a free-running counter
+          - ConnectX-6 Dx and later devices have a UTC format counter

drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c

@@ -93,17 +93,23 @@ static bool mlx5_modify_mtutc_allowed(struct mlx5_core_dev *mdev)
 	return MLX5_CAP_MCAM_FEATURE(mdev, ptpcyc2realtime_modify);
 }
 
-static bool mlx5_is_mtutc_time_adj_cap(struct mlx5_core_dev *mdev, s64 delta)
+static s32 mlx5_ptp_getmaxphase(struct ptp_clock_info *ptp)
 {
-	s64 min = MLX5_MTUTC_OPERATION_ADJUST_TIME_MIN;
-	s64 max = MLX5_MTUTC_OPERATION_ADJUST_TIME_MAX;
+	struct mlx5_clock *clock = container_of(ptp, struct mlx5_clock, ptp_info);
+	struct mlx5_core_dev *mdev;
 
-	if (MLX5_CAP_MCAM_FEATURE(mdev, mtutc_time_adjustment_extended_range)) {
-		min = MLX5_MTUTC_OPERATION_ADJUST_TIME_EXTENDED_MIN;
-		max = MLX5_MTUTC_OPERATION_ADJUST_TIME_EXTENDED_MAX;
-	}
+	mdev = container_of(clock, struct mlx5_core_dev, clock);
+
+	return MLX5_CAP_MCAM_FEATURE(mdev, mtutc_time_adjustment_extended_range) ?
+		       MLX5_MTUTC_OPERATION_ADJUST_TIME_EXTENDED_MAX :
+			     MLX5_MTUTC_OPERATION_ADJUST_TIME_MAX;
+}
+
+static bool mlx5_is_mtutc_time_adj_cap(struct mlx5_core_dev *mdev, s64 delta)
+{
+	s64 max = mlx5_ptp_getmaxphase(&mdev->clock.ptp_info);
 
-	if (delta < min || delta > max)
+	if (delta < -max || delta > max)
 		return false;
 
 	return true;
@@ -351,14 +357,6 @@ static int mlx5_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 
 static int mlx5_ptp_adjphase(struct ptp_clock_info *ptp, s32 delta)
 {
-	struct mlx5_clock *clock = container_of(ptp, struct mlx5_clock, ptp_info);
-	struct mlx5_core_dev *mdev;
-
-	mdev = container_of(clock, struct mlx5_core_dev, clock);
-
-	if (!mlx5_is_mtutc_time_adj_cap(mdev, delta))
-		return -ERANGE;
-
 	return mlx5_ptp_adjtime(ptp, delta);
 }
 
@@ -734,6 +732,7 @@ static const struct ptp_clock_info mlx5_ptp_clock_info = {
 	.pps		= 0,
 	.adjfine	= mlx5_ptp_adjfine,
 	.adjphase	= mlx5_ptp_adjphase,
+	.getmaxphase    = mlx5_ptp_getmaxphase,
 	.adjtime	= mlx5_ptp_adjtime,
 	.gettimex64	= mlx5_ptp_gettimex,
 	.settime64	= mlx5_ptp_settime,

drivers/ptp/ptp_chardev.c

@@ -136,7 +136,10 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
 		caps.pps = ptp->info->pps;
 		caps.n_pins = ptp->info->n_pins;
 		caps.cross_timestamping = ptp->info->getcrosststamp != NULL;
-		caps.adjust_phase = ptp->info->adjphase != NULL;
+		caps.adjust_phase = ptp->info->adjphase != NULL &&
+				    ptp->info->getmaxphase != NULL;
+		if (caps.adjust_phase)
+			caps.max_phase_adj = ptp->info->getmaxphase(ptp->info);
 		if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))
 			err = -EFAULT;
 		break;

drivers/ptp/ptp_clock.c

@@ -135,11 +135,15 @@ static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
 		ptp->dialed_frequency = tx->freq;
 	} else if (tx->modes & ADJ_OFFSET) {
 		if (ops->adjphase) {
+			s32 max_phase_adj = ops->getmaxphase(ops);
 			s32 offset = tx->offset;
 
 			if (!(tx->modes & ADJ_NANO))
 				offset *= NSEC_PER_USEC;
 
+			if (offset > max_phase_adj || offset < -max_phase_adj)
+				return -ERANGE;
+
 			err = ops->adjphase(ops, offset);
 		}
 	} else if (tx->modes == 0) {

drivers/ptp/ptp_clockmatrix.c

@@ -1692,14 +1692,23 @@ static int initialize_dco_operating_mode(struct idtcm_channel *channel)
 /* PTP Hardware Clock interface */
 
 /*
- * Maximum absolute value for write phase offset in picoseconds
- *
- * @channel:  channel
- * @delta_ns: delta in nanoseconds
+ * Maximum absolute value for write phase offset in nanoseconds
  *
  * Destination signed register is 32-bit register in resolution of 50ps
  *
- * 0x7fffffff * 50 =  2147483647 * 50 = 107374182350
+ * 0x7fffffff * 50 =  2147483647 * 50 = 107374182350 ps
+ * Represent 107374182350 ps as 107374182 ns
+ */
+static s32 idtcm_getmaxphase(struct ptp_clock_info *ptp __always_unused)
+{
+	return MAX_ABS_WRITE_PHASE_NANOSECONDS;
+}
+
+/*
+ * Internal function for implementing support for write phase offset
+ *
+ * @channel:  channel
+ * @delta_ns: delta in nanoseconds
  */
 static int _idtcm_adjphase(struct idtcm_channel *channel, s32 delta_ns)
 {
@@ -1708,27 +1717,14 @@ static int _idtcm_adjphase(struct idtcm_channel *channel, s32 delta_ns)
 	u8 i;
 	u8 buf[4] = {0};
 	s32 phase_50ps;
-	s64 offset_ps;
 
 	if (channel->mode != PTP_PLL_MODE_WRITE_PHASE) {
 		err = channel->configure_write_phase(channel);
 		if (err)
 			return err;
 	}
 
-	offset_ps = (s64)delta_ns * 1000;
-
-	/*
-	 * Check for 32-bit signed max * 50:
-	 *
-	 * 0x7fffffff * 50 =  2147483647 * 50 = 107374182350
-	 */
-	if (offset_ps > MAX_ABS_WRITE_PHASE_PICOSECONDS)
-		offset_ps = MAX_ABS_WRITE_PHASE_PICOSECONDS;
-	else if (offset_ps < -MAX_ABS_WRITE_PHASE_PICOSECONDS)
-		offset_ps = -MAX_ABS_WRITE_PHASE_PICOSECONDS;
-
-	phase_50ps = div_s64(offset_ps, 50);
+	phase_50ps = div_s64((s64)delta_ns * 1000, 50);
 
 	for (i = 0; i < 4; i++) {
 		buf[i] = phase_50ps & 0xff;
@@ -2048,6 +2044,7 @@ static const struct ptp_clock_info idtcm_caps = {
 	.n_ext_ts	= MAX_TOD,
 	.n_pins		= MAX_REF_CLK,
 	.adjphase	= &idtcm_adjphase,
+	.getmaxphase	= &idtcm_getmaxphase,
 	.adjfine	= &idtcm_adjfine,
 	.adjtime	= &idtcm_adjtime,
 	.gettime64	= &idtcm_gettime,
@@ -2064,6 +2061,7 @@ static const struct ptp_clock_info idtcm_caps_deprecated = {
 	.n_ext_ts	= MAX_TOD,
 	.n_pins		= MAX_REF_CLK,
 	.adjphase	= &idtcm_adjphase,
+	.getmaxphase    = &idtcm_getmaxphase,
 	.adjfine	= &idtcm_adjfine,
 	.adjtime	= &idtcm_adjtime_deprecated,
 	.gettime64	= &idtcm_gettime,

drivers/ptp/ptp_clockmatrix.h

@@ -18,7 +18,7 @@
 #define MAX_PLL		(8)
 #define MAX_REF_CLK	(16)
 
-#define MAX_ABS_WRITE_PHASE_PICOSECONDS (107374182350LL)
+#define MAX_ABS_WRITE_PHASE_NANOSECONDS (107374182L)
 
 #define TOD_MASK_ADDR		(0xFFA5)
 #define DEFAULT_TOD_MASK	(0x04)

drivers/ptp/ptp_idt82p33.c

@@ -978,24 +978,23 @@ static int idt82p33_enable(struct ptp_clock_info *ptp,
 	return err;
 }
 
+static s32 idt82p33_getmaxphase(__always_unused struct ptp_clock_info *ptp)
+{
+	return WRITE_PHASE_OFFSET_LIMIT;
+}
+
 static int idt82p33_adjwritephase(struct ptp_clock_info *ptp, s32 offset_ns)
 {
 	struct idt82p33_channel *channel =
 		container_of(ptp, struct idt82p33_channel, caps);
 	struct idt82p33 *idt82p33 = channel->idt82p33;
-	s64 offset_regval, offset_fs;
+	s64 offset_regval;
 	u8 val[4] = {0};
 	int err;
 
-	offset_fs = (s64)(-offset_ns) * 1000000;
-
-	if (offset_fs > WRITE_PHASE_OFFSET_LIMIT)
-		offset_fs = WRITE_PHASE_OFFSET_LIMIT;
-	else if (offset_fs < -WRITE_PHASE_OFFSET_LIMIT)
-		offset_fs = -WRITE_PHASE_OFFSET_LIMIT;
-
 	/* Convert from phaseoffset_fs to register value */
-	offset_regval = div_s64(offset_fs * 1000, IDT_T0DPLL_PHASE_RESOL);
+	offset_regval = div_s64((s64)(-offset_ns) * 1000000000ll,
+				IDT_T0DPLL_PHASE_RESOL);
 
 	val[0] = offset_regval & 0xFF;
 	val[1] = (offset_regval >> 8) & 0xFF;
@@ -1175,6 +1174,7 @@ static void idt82p33_caps_init(u32 index, struct ptp_clock_info *caps,
 	caps->n_ext_ts = MAX_PHC_PLL,
 	caps->n_pins = max_pins,
 	caps->adjphase = idt82p33_adjwritephase,
+	caps->getmaxphase = idt82p33_getmaxphase,
 	caps->adjfine = idt82p33_adjfine;
 	caps->adjtime = idt82p33_adjtime;
 	caps->gettime64 = idt82p33_gettime;

drivers/ptp/ptp_idt82p33.h

@@ -43,9 +43,9 @@
 #define DEFAULT_OUTPUT_MASK_PLL1	DEFAULT_OUTPUT_MASK_PLL0
 
 /**
- * @brief Maximum absolute value for write phase offset in femtoseconds
+ * @brief Maximum absolute value for write phase offset in nanoseconds
  */
-#define WRITE_PHASE_OFFSET_LIMIT (20000052084ll)
+#define WRITE_PHASE_OFFSET_LIMIT (20000l)
 
 /** @brief Phase offset resolution
  *

drivers/ptp/ptp_ocp.c

@@ -1124,6 +1124,12 @@ ptp_ocp_null_adjfine(struct ptp_clock_info *ptp_info, long scaled_ppm)
 	return -EOPNOTSUPP;
 }
 
+static s32
+ptp_ocp_null_getmaxphase(struct ptp_clock_info *ptp_info)
+{
+	return 0;
+}
+
 static int
 ptp_ocp_null_adjphase(struct ptp_clock_info *ptp_info, s32 phase_ns)
 {
@@ -1239,6 +1245,7 @@ static const struct ptp_clock_info ptp_ocp_clock_info = {
 	.adjtime	= ptp_ocp_adjtime,
 	.adjfine	= ptp_ocp_null_adjfine,
 	.adjphase	= ptp_ocp_null_adjphase,
+	.getmaxphase	= ptp_ocp_null_getmaxphase,
 	.enable		= ptp_ocp_enable,
 	.verify		= ptp_ocp_verify,
 	.pps		= true,

drivers/ptp/ptp_sysfs.c

@@ -18,6 +18,17 @@ static ssize_t clock_name_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(clock_name);
 
+static ssize_t max_phase_adjustment_show(struct device *dev,
+					 struct device_attribute *attr,
+					 char *page)
+{
+	struct ptp_clock *ptp = dev_get_drvdata(dev);
+
+	return snprintf(page, PAGE_SIZE - 1, "%d\n",
+			ptp->info->getmaxphase(ptp->info));
+}
+static DEVICE_ATTR_RO(max_phase_adjustment);
+
 #define PTP_SHOW_INT(name, var)						\
 static ssize_t var##_show(struct device *dev,				\
 			   struct device_attribute *attr, char *page)	\
@@ -309,6 +320,7 @@ static struct attribute *ptp_attrs[] = {
 	&dev_attr_clock_name.attr,
 
 	&dev_attr_max_adjustment.attr,
+	&dev_attr_max_phase_adjustment.attr,
 	&dev_attr_n_alarms.attr,
 	&dev_attr_n_external_timestamps.attr,
 	&dev_attr_n_periodic_outputs.attr,

include/linux/ptp_clock_kernel.h

@@ -77,8 +77,14 @@ struct ptp_system_timestamp {
  *            nominal frequency in parts per million, but with a
  *            16 bit binary fractional field.
  *
- * @adjphase:  Adjusts the phase offset of the hardware clock.
- *             parameter delta: Desired change in nanoseconds.
+ * @adjphase:  Indicates that the PHC should use an internal servo
+ *             algorithm to correct the provided phase offset.
+ *             parameter delta: PHC servo phase adjustment target
+ *                              in nanoseconds.
+ *
+ * @getmaxphase:  Advertises maximum offset that can be provided
+ *                to the hardware clock's phase control functionality
+ *                through adjphase.
  *
  * @adjtime:  Shifts the time of the hardware clock.
  *            parameter delta: Desired change in nanoseconds.
@@ -169,6 +175,7 @@ struct ptp_clock_info {
 	struct ptp_pin_desc *pin_config;
 	int (*adjfine)(struct ptp_clock_info *ptp, long scaled_ppm);
 	int (*adjphase)(struct ptp_clock_info *ptp, s32 phase);
+	s32 (*getmaxphase)(struct ptp_clock_info *ptp);
 	int (*adjtime)(struct ptp_clock_info *ptp, s64 delta);
 	int (*gettime64)(struct ptp_clock_info *ptp, struct timespec64 *ts);
 	int (*gettimex64)(struct ptp_clock_info *ptp, struct timespec64 *ts,

include/uapi/linux/ptp_clock.h

@@ -95,7 +95,8 @@ struct ptp_clock_caps {
 	int cross_timestamping;
 	/* Whether the clock supports adjust phase */
 	int adjust_phase;
-	int rsv[12];   /* Reserved for future use. */
+	int max_phase_adj; /* Maximum phase adjustment in nanoseconds. */
+	int rsv[11];       /* Reserved for future use. */
 };
 
 struct ptp_extts_request {