From: Satendra Singh Thakur <satendra.t@samsung.com>
To: mchehab@kernel.org, max.kellermann@gmail.com,
        sakari.ailus@linux.intel.com, mingo@kernel.org, hans.verkuil@cisco.com,
        yamada.masahiro@socionext.com, shuah@kernel.org
Cc: satendra.t@samsung.com, linux-media@vger.kernel.org,
        linux-kernel@vger.kernel.org, taeyoung0432.lee@samsung.com,
        jackee.lee@samsung.com, p.awasthi@samsung.com, hemanshu.s@samsung.com,
        madhur.verma@samsung.com
Subject: [PATCH v3] [DVB][FRONTEND] Added a new ioctl for optimizing
 frontend property set operation
Date: Mon, 18 Sep 2017 04:15:16 -0400
Message-Id: <1505722516-30026-1-git-send-email-satendra.t@samsung.com>
In-Reply-To: <20170915082808.0ca12351@vento.lan>
Content-Type: text/plain; charset="utf-8"
CMS-TYPE: 105P
DLP-Filter: Pass
References: <20170915082808.0ca12351@vento.lan>
        <CGME20170918081552epcas5p4bee3acb340e76b74b4cd89dd23138f4d@epcas5p4.samsung.com>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 15193
Lines: 498

Hello  Mr Chehab,
Thanks for the review.
I have modified the code and documentation as per your comments.
Please let me know if this patch is ready for merging.

Signed-off-by: Satendra Singh Thakur <satendra.t@samsung.com>
---
 Documentation/media/uapi/dvb/fe-get-property.rst |  24 ++-
 drivers/media/dvb-core/dvb_frontend.c            | 191 ++++++++++++++---------
 include/uapi/linux/dvb/frontend.h                |  24 +++
 3 files changed, 158 insertions(+), 81 deletions(-)

diff --git a/Documentation/media/uapi/dvb/fe-get-property.rst b/Documentation/media/uapi/dvb/fe-get-property.rst
index 015d4db..b63a588 100644
--- a/Documentation/media/uapi/dvb/fe-get-property.rst
+++ b/Documentation/media/uapi/dvb/fe-get-property.rst
@@ -2,14 +2,14 @@
 
 .. _FE_GET_PROPERTY:
 
-**************************************
-ioctl FE_SET_PROPERTY, FE_GET_PROPERTY
-**************************************
+**************************************************************
+ioctl FE_SET_PROPERTY, FE_GET_PROPERTY, FE_SET_PROPERTY_SHORT
+**************************************************************
 
 Name
 ====
 
-FE_SET_PROPERTY - FE_GET_PROPERTY - FE_SET_PROPERTY sets one or more frontend properties. - FE_GET_PROPERTY returns one or more frontend properties.
+FE_SET_PROPERTY and FE_SET_PROPERTY_SHORT set one or more frontend properties. FE_GET_PROPERTY returns one or more frontend properties.
 
 
 Synopsis
@@ -21,6 +21,8 @@ Synopsis
 .. c:function:: int ioctl( int fd, FE_SET_PROPERTY, struct dtv_properties *argp )
     :name: FE_SET_PROPERTY
 
+.. c:function:: int ioctl( int fd, FE_SET_PROPERTY_SHORT, struct dtv_properties_short *argp )
+    :name: FE_SET_PROPERTY_SHORT
 
 Arguments
 =========
@@ -29,15 +31,16 @@ Arguments
     File descriptor returned by :ref:`open() <frontend_f_open>`.
 
 ``argp``
-    pointer to struct :c:type:`dtv_properties`
+    Pointer to struct :c:type:`dtv_properties` or
+	struct :c:type:`dtv_properties_short`.
 
 
 Description
 ===========
 
-All DVB frontend devices support the ``FE_SET_PROPERTY`` and
-``FE_GET_PROPERTY`` ioctls. The supported properties and statistics
-depends on the delivery system and on the device:
+All DVB frontend devices support the ``FE_SET_PROPERTY``, ``FE_GET_PROPERTY``
+and ``FE_SET_PROPERTY_SHORT`` ioctls. The supported  properties and
+statistics depends on the delivery system and on the device:
 
 -  ``FE_SET_PROPERTY:``
 
@@ -60,6 +63,11 @@ depends on the delivery system and on the device:
 
    -  This call only requires read-only access to the device.
 
+-  ``FE_SET_PROPERTY_SHORT:``
+
+   -  This ioctl is similar to FE_SET_PROPERTY ioctl mentioned above
+      except that the arguments of the former utilize a struct :c:type:`dtv_property_short`
+      which is smaller in size.
 
 Return Value
 ============
diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
index e3fff8f..3e49127 100644
--- a/drivers/media/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb-core/dvb_frontend.c
@@ -1081,28 +1081,25 @@ static struct dtv_cmds_h dtv_cmds[DTV_MAX_COMMAND + 1] = {
 	_DTV_CMD(DTV_STAT_TOTAL_BLOCK_COUNT, 0, 0),
 };
 
-static void dtv_property_dump(struct dvb_frontend *fe,
-			      bool is_set,
+static void dtv_get_property_dump(struct dvb_frontend *fe,
 			      struct dtv_property *tvp)
 {
 	int i;
 
 	if (tvp->cmd <= 0 || tvp->cmd > DTV_MAX_COMMAND) {
-		dev_warn(fe->dvb->device, "%s: %s tvp.cmd = 0x%08x undefined\n",
-				__func__,
-				is_set ? "SET" : "GET",
-				tvp->cmd);
+		dev_warn(fe->dvb->device, "%s: GET tvp.cmd = 0x%08x undefined\n"
+				 , __func__,
+				 tvp->cmd);
 		return;
 	}
 
-	dev_dbg(fe->dvb->device, "%s: %s tvp.cmd    = 0x%08x (%s)\n", __func__,
-		is_set ? "SET" : "GET",
-		tvp->cmd,
-		dtv_cmds[tvp->cmd].name);
+	dev_dbg(fe->dvb->device, "%s: GET tvp.cmd    = 0x%08x (%s)\n", __func__,
+		   	tvp->cmd,
+		   	dtv_cmds[tvp->cmd].name);
 
 	if (dtv_cmds[tvp->cmd].buffer) {
 		dev_dbg(fe->dvb->device, "%s: tvp.u.buffer.len = 0x%02x\n",
-			__func__, tvp->u.buffer.len);
+				__func__, tvp->u.buffer.len);
 
 		for(i = 0; i < tvp->u.buffer.len; i++)
 			dev_dbg(fe->dvb->device,
@@ -1515,7 +1512,7 @@ static int dtv_property_process_get(struct dvb_frontend *fe,
 			return r;
 	}
 
-	dtv_property_dump(fe, false, tvp);
+	dtv_get_property_dump(fe, tvp);
 
 	return 0;
 }
@@ -1738,23 +1735,35 @@ static int dvbv3_set_delivery_system(struct dvb_frontend *fe)
 	return emulate_delivery_system(fe, delsys);
 }
 
+/**
+ * dtv_property_process_set -  Sets a single DTV property
+ * @fe:		Pointer to &struct dvb_frontend
+ * @file:	Pointer to &struct file
+ * @cmd:	Digital TV command
+ * @data:	An unsigned 32-bits number
+ *
+ * This routine assigns the property
+ * value to the corresponding member of
+ * &struct dtv_frontend_properties
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
 static int dtv_property_process_set(struct dvb_frontend *fe,
-				    struct dtv_property *tvp,
-				    struct file *file)
+					struct file *file,
+					u32 cmd, u32 data)
 {
 	int r = 0;
 	struct dtv_frontend_properties *c = &fe->dtv_property_cache;
-
-	/* Allow the frontend to validate incoming properties */
-	if (fe->ops.set_property) {
-		r = fe->ops.set_property(fe, tvp);
-		if (r < 0)
-			return r;
-	}
-
-	dtv_property_dump(fe, true, tvp);
-
-	switch(tvp->cmd) {
+	/** Dump DTV command name and value*/
+	if (!cmd || cmd > DTV_MAX_COMMAND)
+		dev_warn(fe->dvb->device, "%s: SET cmd 0x%08x undefined\n",
+				 __func__, cmd);
+	else
+		dev_dbg(fe->dvb->device,
+				"%s: SET cmd 0x%08x (%s) to 0x%08x\n",
+				__func__, cmd, dtv_cmds[cmd].name, data);
+	switch (cmd) {
 	case DTV_CLEAR:
 		/*
 		 * Reset a cache of data specific to the frontend here. This does
@@ -1767,140 +1776,140 @@ static int dtv_property_process_set(struct dvb_frontend *fe,
 		 * tunerequest so we can pass validation in the FE_SET_FRONTEND
 		 * ioctl.
 		 */
-		c->state = tvp->cmd;
+		c->state = cmd;
 		dev_dbg(fe->dvb->device, "%s: Finalised property cache\n",
 				__func__);
 
 		r = dtv_set_frontend(fe);
 		break;
 	case DTV_FREQUENCY:
-		c->frequency = tvp->u.data;
+		c->frequency = data;
 		break;
 	case DTV_MODULATION:
-		c->modulation = tvp->u.data;
+		c->modulation = data;
 		break;
 	case DTV_BANDWIDTH_HZ:
-		c->bandwidth_hz = tvp->u.data;
+		c->bandwidth_hz = data;
 		break;
 	case DTV_INVERSION:
-		c->inversion = tvp->u.data;
+		c->inversion = data;
 		break;
 	case DTV_SYMBOL_RATE:
-		c->symbol_rate = tvp->u.data;
+		c->symbol_rate = data;
 		break;
 	case DTV_INNER_FEC:
-		c->fec_inner = tvp->u.data;
+		c->fec_inner = data;
 		break;
 	case DTV_PILOT:
-		c->pilot = tvp->u.data;
+		c->pilot = data;
 		break;
 	case DTV_ROLLOFF:
-		c->rolloff = tvp->u.data;
+		c->rolloff = data;
 		break;
 	case DTV_DELIVERY_SYSTEM:
-		r = dvbv5_set_delivery_system(fe, tvp->u.data);
+		r = dvbv5_set_delivery_system(fe, data);
 		break;
 	case DTV_VOLTAGE:
-		c->voltage = tvp->u.data;
+		c->voltage = data;
 		r = dvb_frontend_ioctl_legacy(file, FE_SET_VOLTAGE,
 			(void *)c->voltage);
 		break;
 	case DTV_TONE:
-		c->sectone = tvp->u.data;
+		c->sectone = data;
 		r = dvb_frontend_ioctl_legacy(file, FE_SET_TONE,
 			(void *)c->sectone);
 		break;
 	case DTV_CODE_RATE_HP:
-		c->code_rate_HP = tvp->u.data;
+		c->code_rate_HP = data;
 		break;
 	case DTV_CODE_RATE_LP:
-		c->code_rate_LP = tvp->u.data;
+		c->code_rate_LP = data;
 		break;
 	case DTV_GUARD_INTERVAL:
-		c->guard_interval = tvp->u.data;
+		c->guard_interval = data;
 		break;
 	case DTV_TRANSMISSION_MODE:
-		c->transmission_mode = tvp->u.data;
+		c->transmission_mode = data;
 		break;
 	case DTV_HIERARCHY:
-		c->hierarchy = tvp->u.data;
+		c->hierarchy = data;
 		break;
 	case DTV_INTERLEAVING:
-		c->interleaving = tvp->u.data;
+		c->interleaving = data;
 		break;
 
 	/* ISDB-T Support here */
 	case DTV_ISDBT_PARTIAL_RECEPTION:
-		c->isdbt_partial_reception = tvp->u.data;
+		c->isdbt_partial_reception = data;
 		break;
 	case DTV_ISDBT_SOUND_BROADCASTING:
-		c->isdbt_sb_mode = tvp->u.data;
+		c->isdbt_sb_mode = data;
 		break;
 	case DTV_ISDBT_SB_SUBCHANNEL_ID:
-		c->isdbt_sb_subchannel = tvp->u.data;
+		c->isdbt_sb_subchannel = data;
 		break;
 	case DTV_ISDBT_SB_SEGMENT_IDX:
-		c->isdbt_sb_segment_idx = tvp->u.data;
+		c->isdbt_sb_segment_idx = data;
 		break;
 	case DTV_ISDBT_SB_SEGMENT_COUNT:
-		c->isdbt_sb_segment_count = tvp->u.data;
+		c->isdbt_sb_segment_count = data;
 		break;
 	case DTV_ISDBT_LAYER_ENABLED:
-		c->isdbt_layer_enabled = tvp->u.data;
+		c->isdbt_layer_enabled = data;
 		break;
 	case DTV_ISDBT_LAYERA_FEC:
-		c->layer[0].fec = tvp->u.data;
+		c->layer[0].fec = data;
 		break;
 	case DTV_ISDBT_LAYERA_MODULATION:
-		c->layer[0].modulation = tvp->u.data;
+		c->layer[0].modulation = data;
 		break;
 	case DTV_ISDBT_LAYERA_SEGMENT_COUNT:
-		c->layer[0].segment_count = tvp->u.data;
+		c->layer[0].segment_count = data;
 		break;
 	case DTV_ISDBT_LAYERA_TIME_INTERLEAVING:
-		c->layer[0].interleaving = tvp->u.data;
+		c->layer[0].interleaving = data;
 		break;
 	case DTV_ISDBT_LAYERB_FEC:
-		c->layer[1].fec = tvp->u.data;
+		c->layer[1].fec = data;
 		break;
 	case DTV_ISDBT_LAYERB_MODULATION:
-		c->layer[1].modulation = tvp->u.data;
+		c->layer[1].modulation = data;
 		break;
 	case DTV_ISDBT_LAYERB_SEGMENT_COUNT:
-		c->layer[1].segment_count = tvp->u.data;
+		c->layer[1].segment_count = data;
 		break;
 	case DTV_ISDBT_LAYERB_TIME_INTERLEAVING:
-		c->layer[1].interleaving = tvp->u.data;
+		c->layer[1].interleaving = data;
 		break;
 	case DTV_ISDBT_LAYERC_FEC:
-		c->layer[2].fec = tvp->u.data;
+		c->layer[2].fec = data;
 		break;
 	case DTV_ISDBT_LAYERC_MODULATION:
-		c->layer[2].modulation = tvp->u.data;
+		c->layer[2].modulation = data;
 		break;
 	case DTV_ISDBT_LAYERC_SEGMENT_COUNT:
-		c->layer[2].segment_count = tvp->u.data;
+		c->layer[2].segment_count = data;
 		break;
 	case DTV_ISDBT_LAYERC_TIME_INTERLEAVING:
-		c->layer[2].interleaving = tvp->u.data;
+		c->layer[2].interleaving = data;
 		break;
 
 	/* Multistream support */
 	case DTV_STREAM_ID:
 	case DTV_DVBT2_PLP_ID_LEGACY:
-		c->stream_id = tvp->u.data;
+		c->stream_id = data;
 		break;
 
 	/* ATSC-MH */
 	case DTV_ATSCMH_PARADE_ID:
-		fe->dtv_property_cache.atscmh_parade_id = tvp->u.data;
+		fe->dtv_property_cache.atscmh_parade_id = data;
 		break;
 	case DTV_ATSCMH_RS_FRAME_ENSEMBLE:
-		fe->dtv_property_cache.atscmh_rs_frame_ensemble = tvp->u.data;
+		fe->dtv_property_cache.atscmh_rs_frame_ensemble = data;
 		break;
 
 	case DTV_LNA:
-		c->lna = tvp->u.data;
+		c->lna = data;
 		if (fe->ops.set_lna)
 			r = fe->ops.set_lna(fe);
 		if (r < 0)
@@ -1939,7 +1948,8 @@ static int dvb_frontend_ioctl(struct file *file,
 		return -EPERM;
 	}
 
-	if ((cmd == FE_SET_PROPERTY) || (cmd == FE_GET_PROPERTY))
+	if ((cmd == FE_SET_PROPERTY) || (cmd == FE_GET_PROPERTY)
+	    || (cmd == FE_SET_PROPERTY_SHORT))
 		err = dvb_frontend_ioctl_properties(file, cmd, parg);
 	else {
 		c->state = DTV_UNDEFINED;
@@ -1966,8 +1976,10 @@ static int dvb_frontend_ioctl_properties(struct file *file,
 	dev_dbg(fe->dvb->device, "%s:\n", __func__);
 
 	if (cmd == FE_SET_PROPERTY) {
-		dev_dbg(fe->dvb->device, "%s: properties.num = %d\n", __func__, tvps->num);
-		dev_dbg(fe->dvb->device, "%s: properties.props = %p\n", __func__, tvps->props);
+		dev_dbg(fe->dvb->device, "%s: properties.num = %d\n",
+				__func__, tvps->num);
+		dev_dbg(fe->dvb->device, "%s: properties.props = %p\n",
+				__func__, tvps->props);
 
 		/* Put an arbitrary limit on the number of messages that can
 		 * be sent at once */
@@ -1979,20 +1991,25 @@ static int dvb_frontend_ioctl_properties(struct file *file,
 			return PTR_ERR(tvp);
 
 		for (i = 0; i < tvps->num; i++) {
-			err = dtv_property_process_set(fe, tvp + i, file);
+			err = dtv_property_process_set(fe, file,
+									   (tvp + i)->cmd,
+									   (tvp + i)->u.data);
 			if (err < 0)
 				goto out;
 			(tvp + i)->result = err;
 		}
 
 		if (c->state == DTV_TUNE)
-			dev_dbg(fe->dvb->device, "%s: Property cache is full, tuning\n", __func__);
+			dev_dbg(fe->dvb->device, "%s: Property cache is full, tuning\n",
+					__func__);
 
 	} else if (cmd == FE_GET_PROPERTY) {
 		struct dtv_frontend_properties getp = fe->dtv_property_cache;
 
-		dev_dbg(fe->dvb->device, "%s: properties.num = %d\n", __func__, tvps->num);
-		dev_dbg(fe->dvb->device, "%s: properties.props = %p\n", __func__, tvps->props);
+		dev_dbg(fe->dvb->device, "%s: properties.num = %d\n",
+				__func__, tvps->num);
+		dev_dbg(fe->dvb->device, "%s: properties.props = %p\n",
+				__func__, tvps->props);
 
 		/* Put an arbitrary limit on the number of messages that can
 		 * be sent at once */
@@ -2026,7 +2043,35 @@ static int dvb_frontend_ioctl_properties(struct file *file,
 			err = -EFAULT;
 			goto out;
 		}
-
+	/* New ioctl for optimizing property set*/
+	} else if (cmd == FE_SET_PROPERTY_SHORT) {
+		struct dtv_property_short *tvp_short = NULL;
+		struct dtv_properties_short *tvps_short = parg;
+
+		dev_dbg(fe->dvb->device, "%s: properties.num = %d\n",
+				__func__, tvps_short->num);
+		dev_dbg(fe->dvb->device, "%s: properties.props = %p\n",
+				__func__, tvps_short->props);
+		if ((!tvps_short->num) ||
+		    (tvps_short->num > DTV_IOCTL_MAX_MSGS))
+			return -EINVAL;
+		tvp_short = memdup_user(tvps_short->props,
+		tvps_short->num * sizeof(*tvp_short));
+		if (IS_ERR(tvp_short))
+			return PTR_ERR(tvp_short);
+		for (i = 0; i < tvps_short->num; i++) {
+			err = dtv_property_process_set(fe, file,
+									   (tvp_short + i)->cmd,
+									   (tvp_short + i)->data);
+			if (err < 0) {
+				kfree(tvp_short);
+				return err;
+			}
+		}
+		if (c->state == DTV_TUNE)
+			dev_dbg(fe->dvb->device, "%s: Property cache is full, tuning\n",
+					__func__);
+		kfree(tvp_short);
 	} else
 		err = -EOPNOTSUPP;
 
diff --git a/include/uapi/linux/dvb/frontend.h b/include/uapi/linux/dvb/frontend.h
index 00a20cd..9d96dab 100644
--- a/include/uapi/linux/dvb/frontend.h
+++ b/include/uapi/linux/dvb/frontend.h
@@ -476,6 +476,17 @@ struct dtv_property {
 	int result;
 } __attribute__ ((packed));
 
+/**
+ * struct dtv_property_short - A shorter version of &struct dtv_property
+ *
+ * @cmd:	Digital TV command.
+ * @data:	An unsigned 32-bits number.
+ */
+struct dtv_property_short {
+	__u32 cmd;
+	__u32 data;
+};
+
 /* num of properties cannot exceed DTV_IOCTL_MAX_MSGS per ioctl */
 #define DTV_IOCTL_MAX_MSGS 64
 
@@ -484,6 +495,18 @@ struct dtv_properties {
 	struct dtv_property *props;
 };
 
+/**
+ * struct dtv_properties_short - A variant of &struct dtv_properties
+ * to support &struct dtv_property_short
+ *
+ * @num:	Number of properties
+ * @props:	Pointer to &struct dtv_property_short
+ */
+struct dtv_properties_short {
+	__u32 num;
+	struct dtv_property_short *props;
+};
+
 #if defined(__DVB_CORE__) || !defined (__KERNEL__)
 
 /*
@@ -565,6 +588,7 @@ struct dvb_frontend_event {
 
 #define FE_SET_PROPERTY		   _IOW('o', 82, struct dtv_properties)
 #define FE_GET_PROPERTY		   _IOR('o', 83, struct dtv_properties)
+#define FE_SET_PROPERTY_SHORT	   _IOW('o', 84, struct dtv_properties_short)
 
 /**
  * When set, this flag will disable any zigzagging or other "normal" tuning
-- 
2.7.4