net: microchip: vcap: Add vcap_get_rule

Add function vcap_get_rule which returns a rule based on the internal
rule id.
The entire functionality of reading and decoding the rule from the VCAP
was inside vcap_api_debugfs file. So move the entire implementation in
vcap_api as this is used also by vcap_get_rule.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 772 insertions, 0 deletions

diff --git a/drivers/net/ethernet/microchip/vcap/vcap_api.c b/drivers/net/ethernet/microchip/vcap/vcap_api.c
index f2435d7ab515..27128313f15f 100644
--- a/drivers/net/ethernet/microchip/vcap/vcap_api.c
+++ b/drivers/net/ethernet/microchip/vcap/vcap_api.c
@@ -169,6 +169,227 @@ static void vcap_encode_typegroups(u32 *stream, int sw_width,
 	}
 }
 
+static bool vcap_bitarray_zero(int width, u8 *value)
+{
+	int bytes = DIV_ROUND_UP(width, BITS_PER_BYTE);
+	u8 total = 0, bmask = 0xff;
+	int rwidth = width;
+	int idx;
+
+	for (idx = 0; idx < bytes; ++idx, rwidth -= BITS_PER_BYTE) {
+		if (rwidth && rwidth < BITS_PER_BYTE)
+			bmask = (1 << rwidth) - 1;
+		total += value[idx] & bmask;
+	}
+	return total == 0;
+}
+
+static bool vcap_get_bit(u32 *stream, struct vcap_stream_iter *itr)
+{
+	u32 mask = BIT(itr->reg_bitpos);
+	u32 *p = &stream[itr->reg_idx];
+
+	return !!(*p & mask);
+}
+
+static void vcap_decode_field(u32 *stream, struct vcap_stream_iter *itr,
+			      int width, u8 *value)
+{
+	int idx;
+
+	/* Loop over the field value bits and get the field bits and
+	 * set them in the output value byte array
+	 */
+	for (idx = 0; idx < width; idx++) {
+		u8 bidx = idx & 0x7;
+
+		/* Decode one field value bit */
+		if (vcap_get_bit(stream, itr))
+			*value |= 1 << bidx;
+		vcap_iter_next(itr);
+		if (bidx == 7)
+			value++;
+	}
+}
+
+/* Verify that the type id in the stream matches the type id of the keyset */
+static bool vcap_verify_keystream_keyset(struct vcap_control *vctrl,
+					 enum vcap_type vt,
+					 u32 *keystream,
+					 u32 *mskstream,
+					 enum vcap_keyfield_set keyset)
+{
+	const struct vcap_info *vcap = &vctrl->vcaps[vt];
+	const struct vcap_field *typefld;
+	const struct vcap_typegroup *tgt;
+	const struct vcap_field *fields;
+	struct vcap_stream_iter iter;
+	const struct vcap_set *info;
+	u32 value = 0;
+	u32 mask = 0;
+
+	if (vcap_keyfield_count(vctrl, vt, keyset) == 0)
+		return false;
+
+	info = vcap_keyfieldset(vctrl, vt, keyset);
+	/* Check that the keyset is valid */
+	if (!info)
+		return false;
+
+	/* a type_id of value -1 means that there is no type field */
+	if (info->type_id == (u8)-1)
+		return true;
+
+	/* Get a valid typegroup for the specific keyset */
+	tgt = vcap_keyfield_typegroup(vctrl, vt, keyset);
+	if (!tgt)
+		return false;
+
+	fields = vcap_keyfields(vctrl, vt, keyset);
+	if (!fields)
+		return false;
+
+	typefld = &fields[VCAP_KF_TYPE];
+	vcap_iter_init(&iter, vcap->sw_width, tgt, typefld->offset);
+	vcap_decode_field(mskstream, &iter, typefld->width, (u8 *)&mask);
+	/* no type info if there are no mask bits */
+	if (vcap_bitarray_zero(typefld->width, (u8 *)&mask))
+		return false;
+
+	/* Get the value of the type field in the stream and compare to the
+	 * one define in the vcap keyset
+	 */
+	vcap_iter_init(&iter, vcap->sw_width, tgt, typefld->offset);
+	vcap_decode_field(keystream, &iter, typefld->width, (u8 *)&value);
+
+	return (value & mask) == (info->type_id & mask);
+}
+
+/* Verify that the typegroup bits have the correct values */
+static int vcap_verify_typegroups(u32 *stream, int sw_width,
+				  const struct vcap_typegroup *tgt, bool mask,
+				  int sw_max)
+{
+	struct vcap_stream_iter iter;
+	int sw_cnt, idx;
+
+	vcap_iter_set(&iter, sw_width, tgt, 0);
+	sw_cnt = 0;
+	while (iter.tg->width) {
+		u32 value = 0;
+		u32 tg_value = iter.tg->value;
+
+		if (mask)
+			tg_value = (1 << iter.tg->width) - 1;
+		/* Set position to current typegroup bit */
+		iter.offset = iter.tg->offset;
+		vcap_iter_update(&iter);
+		for (idx = 0; idx < iter.tg->width; idx++) {
+			/* Decode one typegroup bit */
+			if (vcap_get_bit(stream, &iter))
+				value |= 1 << idx;
+			iter.offset++;
+			vcap_iter_update(&iter);
+		}
+		if (value != tg_value)
+			return -EINVAL;
+		iter.tg++; /* next typegroup */
+		sw_cnt++;
+		/* Stop checking more typegroups */
+		if (sw_max && sw_cnt >= sw_max)
+			break;
+	}
+	return 0;
+}
+
+/* Find the subword width of the key typegroup that matches the stream data */
+static int vcap_find_keystream_typegroup_sw(struct vcap_control *vctrl,
+					    enum vcap_type vt, u32 *stream,
+					    bool mask, int sw_max)
+{
+	const struct vcap_typegroup **tgt;
+	int sw_idx, res;
+
+	tgt = vctrl->vcaps[vt].keyfield_set_typegroups;
+	/* Try the longest subword match first */
+	for (sw_idx = vctrl->vcaps[vt].sw_count; sw_idx >= 0; sw_idx--) {
+		if (!tgt[sw_idx])
+			continue;
+
+		res = vcap_verify_typegroups(stream, vctrl->vcaps[vt].sw_width,
+					     tgt[sw_idx], mask, sw_max);
+		if (res == 0)
+			return sw_idx;
+	}
+	return -EINVAL;
+}
+
+/* Verify that the typegroup information, subword count, keyset and type id
+ * are in sync and correct, return the list of matchin keysets
+ */
+int
+vcap_find_keystream_keysets(struct vcap_control *vctrl,
+			    enum vcap_type vt,
+			    u32 *keystream,
+			    u32 *mskstream,
+			    bool mask, int sw_max,
+			    struct vcap_keyset_list *kslist)
+{
+	const struct vcap_set *keyfield_set;
+	int sw_count, idx;
+
+	sw_count = vcap_find_keystream_typegroup_sw(vctrl, vt, keystream, mask,
+						    sw_max);
+	if (sw_count < 0)
+		return sw_count;
+
+	keyfield_set = vctrl->vcaps[vt].keyfield_set;
+	for (idx = 0; idx < vctrl->vcaps[vt].keyfield_set_size; ++idx) {
+		if (keyfield_set[idx].sw_per_item != sw_count)
+			continue;
+
+		if (vcap_verify_keystream_keyset(vctrl, vt, keystream,
+						 mskstream, idx))
+			vcap_keyset_list_add(kslist, idx);
+	}
+	if (kslist->cnt > 0)
+		return 0;
+	return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(vcap_find_keystream_keysets);
+
+/* Read key data from a VCAP address and discover if there are any rule keysets
+ * here
+ */
+int vcap_addr_keysets(struct vcap_control *vctrl,
+		      struct net_device *ndev,
+		      struct vcap_admin *admin,
+		      int addr,
+		      struct vcap_keyset_list *kslist)
+{
+	enum vcap_type vt = admin->vtype;
+	int keyset_sw_regs, idx;
+	u32 key = 0, mask = 0;
+
+	/* Read the cache at the specified address */
+	keyset_sw_regs = DIV_ROUND_UP(vctrl->vcaps[vt].sw_width, 32);
+	vctrl->ops->update(ndev, admin, VCAP_CMD_READ, VCAP_SEL_ALL, addr);
+	vctrl->ops->cache_read(ndev, admin, VCAP_SEL_ENTRY, 0,
+			       keyset_sw_regs);
+	/* Skip uninitialized key/mask entries */
+	for (idx = 0; idx < keyset_sw_regs; ++idx) {
+		key |= ~admin->cache.keystream[idx];
+		mask |= admin->cache.maskstream[idx];
+	}
+	if (key == 0 && mask == 0)
+		return -EINVAL;
+	/* Decode and locate the keysets */
+	return vcap_find_keystream_keysets(vctrl, vt, admin->cache.keystream,
+					   admin->cache.maskstream, false, 0,
+					   kslist);
+}
+EXPORT_SYMBOL_GPL(vcap_addr_keysets);
+
 /* Return the list of keyfields for the keyset */
 const struct vcap_field *vcap_keyfields(struct vcap_control *vctrl,
 					enum vcap_type vt,
@@ -618,6 +839,517 @@ struct vcap_rule_internal *vcap_dup_rule(struct vcap_rule_internal *ri)
 	return duprule;
 }
 
+static void vcap_apply_width(u8 *dst, int width, int bytes)
+{
+	u8 bmask;
+	int idx;
+
+	for (idx = 0; idx < bytes; idx++) {
+		if (width > 0)
+			if (width < 8)
+				bmask = (1 << width) - 1;
+			else
+				bmask = ~0;
+		else
+			bmask = 0;
+		dst[idx] &= bmask;
+		width -= 8;
+	}
+}
+
+static void vcap_copy_from_w32be(u8 *dst, u8 *src, int size, int width)
+{
+	int idx, ridx, wstart, nidx;
+	int tail_bytes = (((size + 4) >> 2) << 2) - size;
+
+	for (idx = 0, ridx = size - 1; idx < size; ++idx, --ridx) {
+		wstart = (idx >> 2) << 2;
+		nidx = wstart + 3 - (idx & 0x3);
+		if (nidx >= size)
+			nidx -= tail_bytes;
+		dst[nidx] = src[ridx];
+	}
+
+	vcap_apply_width(dst, width, size);
+}
+
+static void vcap_copy_action_bit_field(struct vcap_u1_action *field, u8 *value)
+{
+	field->value = (*value) & 0x1;
+}
+
+static void vcap_copy_limited_actionfield(u8 *dstvalue, u8 *srcvalue,
+					  int width, int bytes)
+{
+	memcpy(dstvalue, srcvalue, bytes);
+	vcap_apply_width(dstvalue, width, bytes);
+}
+
+static void vcap_copy_to_client_actionfield(struct vcap_rule_internal *ri,
+					    struct vcap_client_actionfield *field,
+					    u8 *value, u16 width)
+{
+	int field_size = actionfield_size_table[field->ctrl.type];
+
+	if (ri->admin->w32be) {
+		switch (field->ctrl.type) {
+		case VCAP_FIELD_BIT:
+			vcap_copy_action_bit_field(&field->data.u1, value);
+			break;
+		case VCAP_FIELD_U32:
+			vcap_copy_limited_actionfield((u8 *)&field->data.u32.value,
+						      value,
+						      width, field_size);
+			break;
+		case VCAP_FIELD_U48:
+			vcap_copy_from_w32be(field->data.u48.value, value,
+					     field_size, width);
+			break;
+		case VCAP_FIELD_U56:
+			vcap_copy_from_w32be(field->data.u56.value, value,
+					     field_size, width);
+			break;
+		case VCAP_FIELD_U64:
+			vcap_copy_from_w32be(field->data.u64.value, value,
+					     field_size, width);
+			break;
+		case VCAP_FIELD_U72:
+			vcap_copy_from_w32be(field->data.u72.value, value,
+					     field_size, width);
+			break;
+		case VCAP_FIELD_U112:
+			vcap_copy_from_w32be(field->data.u112.value, value,
+					     field_size, width);
+			break;
+		case VCAP_FIELD_U128:
+			vcap_copy_from_w32be(field->data.u128.value, value,
+					     field_size, width);
+			break;
+		};
+	} else {
+		switch (field->ctrl.type) {
+		case VCAP_FIELD_BIT:
+			vcap_copy_action_bit_field(&field->data.u1, value);
+			break;
+		case VCAP_FIELD_U32:
+			vcap_copy_limited_actionfield((u8 *)&field->data.u32.value,
+						      value,
+						      width, field_size);
+			break;
+		case VCAP_FIELD_U48:
+			vcap_copy_limited_actionfield(field->data.u48.value,
+						      value,
+						      width, field_size);
+			break;
+		case VCAP_FIELD_U56:
+			vcap_copy_limited_actionfield(field->data.u56.value,
+						      value,
+						      width, field_size);
+			break;
+		case VCAP_FIELD_U64:
+			vcap_copy_limited_actionfield(field->data.u64.value,
+						      value,
+						      width, field_size);
+			break;
+		case VCAP_FIELD_U72:
+			vcap_copy_limited_actionfield(field->data.u72.value,
+						      value,
+						      width, field_size);
+			break;
+		case VCAP_FIELD_U112:
+			vcap_copy_limited_actionfield(field->data.u112.value,
+						      value,
+						      width, field_size);
+			break;
+		case VCAP_FIELD_U128:
+			vcap_copy_limited_actionfield(field->data.u128.value,
+						      value,
+						      width, field_size);
+			break;
+		};
+	}
+}
+
+static void vcap_copy_key_bit_field(struct vcap_u1_key *field,
+				    u8 *value, u8 *mask)
+{
+	field->value = (*value) & 0x1;
+	field->mask = (*mask) & 0x1;
+}
+
+static void vcap_copy_limited_keyfield(u8 *dstvalue, u8 *dstmask,
+				       u8 *srcvalue, u8 *srcmask,
+				       int width, int bytes)
+{
+	memcpy(dstvalue, srcvalue, bytes);
+	vcap_apply_width(dstvalue, width, bytes);
+	memcpy(dstmask, srcmask, bytes);
+	vcap_apply_width(dstmask, width, bytes);
+}
+
+static void vcap_copy_to_client_keyfield(struct vcap_rule_internal *ri,
+					 struct vcap_client_keyfield *field,
+					 u8 *value, u8 *mask, u16 width)
+{
+	int field_size = keyfield_size_table[field->ctrl.type] / 2;
+
+	if (ri->admin->w32be) {
+		switch (field->ctrl.type) {
+		case VCAP_FIELD_BIT:
+			vcap_copy_key_bit_field(&field->data.u1, value, mask);
+			break;
+		case VCAP_FIELD_U32:
+			vcap_copy_limited_keyfield((u8 *)&field->data.u32.value,
+						   (u8 *)&field->data.u32.mask,
+						   value, mask,
+						   width, field_size);
+			break;
+		case VCAP_FIELD_U48:
+			vcap_copy_from_w32be(field->data.u48.value, value,
+					     field_size, width);
+			vcap_copy_from_w32be(field->data.u48.mask,  mask,
+					     field_size, width);
+			break;
+		case VCAP_FIELD_U56:
+			vcap_copy_from_w32be(field->data.u56.value, value,
+					     field_size, width);
+			vcap_copy_from_w32be(field->data.u56.mask,  mask,
+					     field_size, width);
+			break;
+		case VCAP_FIELD_U64:
+			vcap_copy_from_w32be(field->data.u64.value, value,
+					     field_size, width);
+			vcap_copy_from_w32be(field->data.u64.mask,  mask,
+					     field_size, width);
+			break;
+		case VCAP_FIELD_U72:
+			vcap_copy_from_w32be(field->data.u72.value, value,
+					     field_size, width);
+			vcap_copy_from_w32be(field->data.u72.mask,  mask,
+					     field_size, width);
+			break;
+		case VCAP_FIELD_U112:
+			vcap_copy_from_w32be(field->data.u112.value, value,
+					     field_size, width);
+			vcap_copy_from_w32be(field->data.u112.mask,  mask,
+					     field_size, width);
+			break;
+		case VCAP_FIELD_U128:
+			vcap_copy_from_w32be(field->data.u128.value, value,
+					     field_size, width);
+			vcap_copy_from_w32be(field->data.u128.mask,  mask,
+					     field_size, width);
+			break;
+		};
+	} else {
+		switch (field->ctrl.type) {
+		case VCAP_FIELD_BIT:
+			vcap_copy_key_bit_field(&field->data.u1, value, mask);
+			break;
+		case VCAP_FIELD_U32:
+			vcap_copy_limited_keyfield((u8 *)&field->data.u32.value,
+						   (u8 *)&field->data.u32.mask,
+						   value, mask,
+						   width, field_size);
+			break;
+		case VCAP_FIELD_U48:
+			vcap_copy_limited_keyfield(field->data.u48.value,
+						   field->data.u48.mask,
+						   value, mask,
+						   width, field_size);
+			break;
+		case VCAP_FIELD_U56:
+			vcap_copy_limited_keyfield(field->data.u56.value,
+						   field->data.u56.mask,
+						   value, mask,
+						   width, field_size);
+			break;
+		case VCAP_FIELD_U64:
+			vcap_copy_limited_keyfield(field->data.u64.value,
+						   field->data.u64.mask,
+						   value, mask,
+						   width, field_size);
+			break;
+		case VCAP_FIELD_U72:
+			vcap_copy_limited_keyfield(field->data.u72.value,
+						   field->data.u72.mask,
+						   value, mask,
+						   width, field_size);
+			break;
+		case VCAP_FIELD_U112:
+			vcap_copy_limited_keyfield(field->data.u112.value,
+						   field->data.u112.mask,
+						   value, mask,
+						   width, field_size);
+			break;
+		case VCAP_FIELD_U128:
+			vcap_copy_limited_keyfield(field->data.u128.value,
+						   field->data.u128.mask,
+						   value, mask,
+						   width, field_size);
+			break;
+		};
+	}
+}
+
+static void vcap_rule_alloc_keyfield(struct vcap_rule_internal *ri,
+				     const struct vcap_field *keyfield,
+				     enum vcap_key_field key,
+				     u8 *value, u8 *mask)
+{
+	struct vcap_client_keyfield *field;
+
+	field = kzalloc(sizeof(*field), GFP_KERNEL);
+	if (!field)
+		return;
+	INIT_LIST_HEAD(&field->ctrl.list);
+	field->ctrl.key = key;
+	field->ctrl.type = keyfield->type;
+	vcap_copy_to_client_keyfield(ri, field, value, mask, keyfield->width);
+	list_add_tail(&field->ctrl.list, &ri->data.keyfields);
+}
+
+/* Read key data from a VCAP address and discover if there is a rule keyset
+ * here
+ */
+static bool
+vcap_verify_actionstream_actionset(struct vcap_control *vctrl,
+				   enum vcap_type vt,
+				   u32 *actionstream,
+				   enum vcap_actionfield_set actionset)
+{
+	const struct vcap_typegroup *tgt;
+	const struct vcap_field *fields;
+	const struct vcap_set *info;
+
+	if (vcap_actionfield_count(vctrl, vt, actionset) == 0)
+		return false;
+
+	info = vcap_actionfieldset(vctrl, vt, actionset);
+	/* Check that the actionset is valid */
+	if (!info)
+		return false;
+
+	/* a type_id of value -1 means that there is no type field */
+	if (info->type_id == (u8)-1)
+		return true;
+
+	/* Get a valid typegroup for the specific actionset */
+	tgt = vcap_actionfield_typegroup(vctrl, vt, actionset);
+	if (!tgt)
+		return false;
+
+	fields = vcap_actionfields(vctrl, vt, actionset);
+	if (!fields)
+		return false;
+
+	/* Later this will be expanded with a check of the type id */
+	return true;
+}
+
+/* Find the subword width of the action typegroup that matches the stream data
+ */
+static int vcap_find_actionstream_typegroup_sw(struct vcap_control *vctrl,
+					       enum vcap_type vt, u32 *stream,
+					       int sw_max)
+{
+	const struct vcap_typegroup **tgt;
+	int sw_idx, res;
+
+	tgt = vctrl->vcaps[vt].actionfield_set_typegroups;
+	/* Try the longest subword match first */
+	for (sw_idx = vctrl->vcaps[vt].sw_count; sw_idx >= 0; sw_idx--) {
+		if (!tgt[sw_idx])
+			continue;
+		res = vcap_verify_typegroups(stream, vctrl->vcaps[vt].act_width,
+					     tgt[sw_idx], false, sw_max);
+		if (res == 0)
+			return sw_idx;
+	}
+	return -EINVAL;
+}
+
+/* Verify that the typegroup information, subword count, actionset and type id
+ * are in sync and correct, return the actionset
+ */
+static enum vcap_actionfield_set
+vcap_find_actionstream_actionset(struct vcap_control *vctrl,
+				 enum vcap_type vt,
+				 u32 *stream,
+				 int sw_max)
+{
+	const struct vcap_set *actionfield_set;
+	int sw_count, idx;
+	bool res;
+
+	sw_count = vcap_find_actionstream_typegroup_sw(vctrl, vt, stream,
+						       sw_max);
+	if (sw_count < 0)
+		return sw_count;
+
+	actionfield_set = vctrl->vcaps[vt].actionfield_set;
+	for (idx = 0; idx < vctrl->vcaps[vt].actionfield_set_size; ++idx) {
+		if (actionfield_set[idx].sw_per_item != sw_count)
+			continue;
+
+		res = vcap_verify_actionstream_actionset(vctrl, vt,
+							 stream, idx);
+		if (res)
+			return idx;
+	}
+	return -EINVAL;
+}
+
+/* Store action value in an element in a list for the client */
+static void vcap_rule_alloc_actionfield(struct vcap_rule_internal *ri,
+					const struct vcap_field *actionfield,
+					enum vcap_action_field action,
+					u8 *value)
+{
+	struct vcap_client_actionfield *field;
+
+	field = kzalloc(sizeof(*field), GFP_KERNEL);
+	if (!field)
+		return;
+	INIT_LIST_HEAD(&field->ctrl.list);
+	field->ctrl.action = action;
+	field->ctrl.type = actionfield->type;
+	vcap_copy_to_client_actionfield(ri, field, value, actionfield->width);
+	list_add_tail(&field->ctrl.list, &ri->data.actionfields);
+}
+
+static int vcap_decode_actionset(struct vcap_rule_internal *ri)
+{
+	struct vcap_control *vctrl = ri->vctrl;
+	struct vcap_admin *admin = ri->admin;
+	const struct vcap_field *actionfield;
+	enum vcap_actionfield_set actionset;
+	enum vcap_type vt = admin->vtype;
+	const struct vcap_typegroup *tgt;
+	struct vcap_stream_iter iter;
+	int idx, res, actfield_count;
+	u32 *actstream;
+	u8 value[16];
+
+	actstream = admin->cache.actionstream;
+	res = vcap_find_actionstream_actionset(vctrl, vt, actstream, 0);
+	if (res < 0) {
+		pr_err("%s:%d: could not find valid actionset: %d\n",
+		       __func__, __LINE__, res);
+		return -EINVAL;
+	}
+	actionset = res;
+	actfield_count = vcap_actionfield_count(vctrl, vt, actionset);
+	actionfield = vcap_actionfields(vctrl, vt, actionset);
+	tgt = vcap_actionfield_typegroup(vctrl, vt, actionset);
+	/* Start decoding the stream */
+	for (idx = 0; idx < actfield_count; ++idx) {
+		if (actionfield[idx].width <= 0)
+			continue;
+		/* Get the action */
+		memset(value, 0, DIV_ROUND_UP(actionfield[idx].width, 8));
+		vcap_iter_init(&iter, vctrl->vcaps[vt].act_width, tgt,
+			       actionfield[idx].offset);
+		vcap_decode_field(actstream, &iter, actionfield[idx].width,
+				  value);
+		/* Skip if no bits are set */
+		if (vcap_bitarray_zero(actionfield[idx].width, value))
+			continue;
+		vcap_rule_alloc_actionfield(ri, &actionfield[idx], idx, value);
+		/* Later the action id will also be checked */
+	}
+	return vcap_set_rule_set_actionset((struct vcap_rule *)ri, actionset);
+}
+
+static int vcap_decode_keyset(struct vcap_rule_internal *ri)
+{
+	struct vcap_control *vctrl = ri->vctrl;
+	struct vcap_stream_iter kiter, miter;
+	struct vcap_admin *admin = ri->admin;
+	enum vcap_keyfield_set keysets[10];
+	const struct vcap_field *keyfield;
+	enum vcap_type vt = admin->vtype;
+	const struct vcap_typegroup *tgt;
+	struct vcap_keyset_list matches;
+	enum vcap_keyfield_set keyset;
+	int idx, res, keyfield_count;
+	u32 *maskstream;
+	u32 *keystream;
+	u8 value[16];
+	u8 mask[16];
+
+	keystream = admin->cache.keystream;
+	maskstream = admin->cache.maskstream;
+	matches.keysets = keysets;
+	matches.cnt = 0;
+	matches.max = ARRAY_SIZE(keysets);
+	res = vcap_find_keystream_keysets(vctrl, vt, keystream, maskstream,
+					  false, 0, &matches);
+	if (res < 0) {
+		pr_err("%s:%d: could not find valid keysets: %d\n",
+		       __func__, __LINE__, res);
+		return -EINVAL;
+	}
+	keyset = matches.keysets[0];
+	keyfield_count = vcap_keyfield_count(vctrl, vt, keyset);
+	keyfield = vcap_keyfields(vctrl, vt, keyset);
+	tgt = vcap_keyfield_typegroup(vctrl, vt, keyset);
+	/* Start decoding the streams */
+	for (idx = 0; idx < keyfield_count; ++idx) {
+		if (keyfield[idx].width <= 0)
+			continue;
+		/* First get the mask */
+		memset(mask, 0, DIV_ROUND_UP(keyfield[idx].width, 8));
+		vcap_iter_init(&miter, vctrl->vcaps[vt].sw_width, tgt,
+			       keyfield[idx].offset);
+		vcap_decode_field(maskstream, &miter, keyfield[idx].width,
+				  mask);
+		/* Skip if no mask bits are set */
+		if (vcap_bitarray_zero(keyfield[idx].width, mask))
+			continue;
+		/* Get the key */
+		memset(value, 0, DIV_ROUND_UP(keyfield[idx].width, 8));
+		vcap_iter_init(&kiter, vctrl->vcaps[vt].sw_width, tgt,
+			       keyfield[idx].offset);
+		vcap_decode_field(keystream, &kiter, keyfield[idx].width,
+				  value);
+		vcap_rule_alloc_keyfield(ri, &keyfield[idx], idx, value, mask);
+	}
+	return vcap_set_rule_set_keyset((struct vcap_rule *)ri, keyset);
+}
+
+/* Read VCAP content into the VCAP cache */
+static int vcap_read_rule(struct vcap_rule_internal *ri)
+{
+	struct vcap_admin *admin = ri->admin;
+	int sw_idx, ent_idx = 0, act_idx = 0;
+	u32 addr = ri->addr;
+
+	if (!ri->size || !ri->keyset_sw_regs || !ri->actionset_sw_regs) {
+		pr_err("%s:%d: rule is empty\n", __func__, __LINE__);
+		return -EINVAL;
+	}
+	vcap_erase_cache(ri);
+	/* Use the values in the streams to read the VCAP cache */
+	for (sw_idx = 0; sw_idx < ri->size; sw_idx++, addr++) {
+		ri->vctrl->ops->update(ri->ndev, admin, VCAP_CMD_READ,
+				       VCAP_SEL_ALL, addr);
+		ri->vctrl->ops->cache_read(ri->ndev, admin,
+					   VCAP_SEL_ENTRY, ent_idx,
+					   ri->keyset_sw_regs);
+		ri->vctrl->ops->cache_read(ri->ndev, admin,
+					   VCAP_SEL_ACTION, act_idx,
+					   ri->actionset_sw_regs);
+		if (sw_idx == 0)
+			ri->vctrl->ops->cache_read(ri->ndev, admin,
+						   VCAP_SEL_COUNTER,
+						   ri->counter_id, 0);
+		ent_idx += ri->keyset_sw_regs;
+		act_idx += ri->actionset_sw_regs;
+	}
+	return 0;
+}
+
 /* Write VCAP cache content to the VCAP HW instance */
 static int vcap_write_rule(struct vcap_rule_internal *ri)
 {
@@ -1183,6 +1915,46 @@ void vcap_free_rule(struct vcap_rule *rule)
 }
 EXPORT_SYMBOL_GPL(vcap_free_rule);
 
+struct vcap_rule *vcap_get_rule(struct vcap_control *vctrl, u32 id)
+{
+	struct vcap_rule_internal *elem;
+	struct vcap_rule_internal *ri;
+	int err;
+
+	ri = NULL;
+
+	err = vcap_api_check(vctrl);
+	if (err)
+		return ERR_PTR(err);
+	elem = vcap_lookup_rule(vctrl, id);
+	if (!elem)
+		return NULL;
+	mutex_lock(&elem->admin->lock);
+	ri = vcap_dup_rule(elem);
+	if (IS_ERR(ri))
+		goto unlock;
+	err = vcap_read_rule(ri);
+	if (err) {
+		ri = ERR_PTR(err);
+		goto unlock;
+	}
+	err = vcap_decode_keyset(ri);
+	if (err) {
+		ri = ERR_PTR(err);
+		goto unlock;
+	}
+	err = vcap_decode_actionset(ri);
+	if (err) {
+		ri = ERR_PTR(err);
+		goto unlock;
+	}
+
+unlock:
+	mutex_unlock(&elem->admin->lock);
+	return (struct vcap_rule *)ri;
+}
+EXPORT_SYMBOL_GPL(vcap_get_rule);
+
 /* Return the alignment offset for a new rule address */
 static int vcap_valid_rule_move(struct vcap_rule_internal *el, int offset)
 {