net: ipa: verify command channel TLV count

In commit 8797972a ("net: ipa: remove command info pool"), the
maximum number of IPA commands that would be sent in a single
transaction was defined.  That number can't exceed the size of the
TLV FIFO on the command channel, and we can check that at runtime.

To add this check, pass a new flag to gsi_channel_data_valid() to
indicate the channel being checked is being used for IPA commands.
Knowing that we can also verify the channel direction is correct.

Use a new local variable that refers to the command-specific portion
of the data being checked.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ipa/gsi.c

@@ -2001,9 +2001,10 @@ static void gsi_channel_evt_ring_exit(struct gsi_channel *channel)
 	gsi_evt_ring_id_free(gsi, evt_ring_id);
 }
 
-static bool gsi_channel_data_valid(struct gsi *gsi,
+static bool gsi_channel_data_valid(struct gsi *gsi, bool command,
 				   const struct ipa_gsi_endpoint_data *data)
 {
+	const struct gsi_channel_data *channel_data;
 	u32 channel_id = data->channel_id;
 	struct device *dev = gsi->dev;
 
@@ -2019,10 +2020,24 @@ static bool gsi_channel_data_valid(struct gsi *gsi,
 		return false;
 	}
 
-	if (!data->channel.tlv_count ||
-	    data->channel.tlv_count > GSI_TLV_MAX) {
+	if (command && !data->toward_ipa) {
+		dev_err(dev, "command channel %u is not TX\n", channel_id);
+		return false;
+	}
+
+	channel_data = &data->channel;
+
+	if (!channel_data->tlv_count ||
+	    channel_data->tlv_count > GSI_TLV_MAX) {
 		dev_err(dev, "channel %u bad tlv_count %u; must be 1..%u\n",
-			channel_id, data->channel.tlv_count, GSI_TLV_MAX);
+			channel_id, channel_data->tlv_count, GSI_TLV_MAX);
+		return false;
+	}
+
+	if (command && IPA_COMMAND_TRANS_TRE_MAX > channel_data->tlv_count) {
+		dev_err(dev, "command TRE max too big for channel %u (%u > %u)\n",
+			channel_id, IPA_COMMAND_TRANS_TRE_MAX,
+			channel_data->tlv_count);
 		return false;
 	}
 
@@ -2031,22 +2046,22 @@ static bool gsi_channel_data_valid(struct gsi *gsi,
 	 * gsi_channel_tre_max() is computed, tre_count has to be almost
 	 * twice the TLV FIFO size to satisfy this requirement.
 	 */
-	if (data->channel.tre_count < 2 * data->channel.tlv_count - 1) {
+	if (channel_data->tre_count < 2 * channel_data->tlv_count - 1) {
 		dev_err(dev, "channel %u TLV count %u exceeds TRE count %u\n",
-			channel_id, data->channel.tlv_count,
-			data->channel.tre_count);
+			channel_id, channel_data->tlv_count,
+			channel_data->tre_count);
 		return false;
 	}
 
-	if (!is_power_of_2(data->channel.tre_count)) {
+	if (!is_power_of_2(channel_data->tre_count)) {
 		dev_err(dev, "channel %u bad tre_count %u; not power of 2\n",
-			channel_id, data->channel.tre_count);
+			channel_id, channel_data->tre_count);
 		return false;
 	}
 
-	if (!is_power_of_2(data->channel.event_count)) {
+	if (!is_power_of_2(channel_data->event_count)) {
 		dev_err(dev, "channel %u bad event_count %u; not power of 2\n",
-			channel_id, data->channel.event_count);
+			channel_id, channel_data->event_count);
 		return false;
 	}
 
@@ -2062,7 +2077,7 @@ static int gsi_channel_init_one(struct gsi *gsi,
 	u32 tre_count;
 	int ret;
 
-	if (!gsi_channel_data_valid(gsi, data))
+	if (!gsi_channel_data_valid(gsi, command, data))
 		return -EINVAL;
 
 	/* Worst case we need an event for every outstanding TRE */