net: ipa: specify RX aggregation time limit in config data

Don't assume that a 500 microsecond time limit should be used for
all receive endpoints that support aggregation.  Instead, specify
the time limit to use in the configuration data.

Set a 500 microsecond limit for all existing RX endpoints, as before.

Checking for overflow for the time limit field is a bit complicated.
Rather than duplicate a lot of code in ipa_endpoint_data_valid_one(),
call WARN() if any value is found to be too large when encoding it.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ipa/ipa_data-v3.1.c

@@ -103,6 +103,7 @@ static const struct ipa_gsi_endpoint_data ipa_gsi_endpoint_data[] = {
 				.rx = {
 					.buffer_size	= 8192,
 					.pad_align	= ilog2(sizeof(u32)),
+					.aggr_time_limit = 500,
 				},
 			},
 		},
@@ -150,6 +151,7 @@ static const struct ipa_gsi_endpoint_data ipa_gsi_endpoint_data[] = {
 				.aggregation	= true,
 				.rx = {
 					.buffer_size	= 8192,
+					.aggr_time_limit = 500,
 					.aggr_close_eof	= true,
 				},
 			},

drivers/net/ipa/ipa_data-v3.5.1.c

@@ -94,6 +94,7 @@ static const struct ipa_gsi_endpoint_data ipa_gsi_endpoint_data[] = {
 				.rx = {
 					.buffer_size	= 8192,
 					.pad_align	= ilog2(sizeof(u32)),
+					.aggr_time_limit = 500,
 				},
 			},
 		},
@@ -142,6 +143,7 @@ static const struct ipa_gsi_endpoint_data ipa_gsi_endpoint_data[] = {
 				.aggregation	= true,
 				.rx = {
 					.buffer_size	= 8192,
+					.aggr_time_limit = 500,
 					.aggr_close_eof	= true,
 				},
 			},

drivers/net/ipa/ipa_data-v4.11.c

@@ -88,6 +88,7 @@ static const struct ipa_gsi_endpoint_data ipa_gsi_endpoint_data[] = {
 				.rx = {
 					.buffer_size	= 8192,
 					.pad_align	= ilog2(sizeof(u32)),
+					.aggr_time_limit = 500,
 				},
 			},
 		},
@@ -135,6 +136,7 @@ static const struct ipa_gsi_endpoint_data ipa_gsi_endpoint_data[] = {
 				.aggregation	= true,
 				.rx = {
 					.buffer_size	= 32768,
+					.aggr_time_limit = 500,
 					.aggr_close_eof	= true,
 				},
 			},

drivers/net/ipa/ipa_data-v4.2.c

@@ -84,6 +84,7 @@ static const struct ipa_gsi_endpoint_data ipa_gsi_endpoint_data[] = {
 				.rx = {
 					.buffer_size	= 8192,
 					.pad_align	= ilog2(sizeof(u32)),
+					.aggr_time_limit = 500,
 				},
 			},
 		},
@@ -132,6 +133,7 @@ static const struct ipa_gsi_endpoint_data ipa_gsi_endpoint_data[] = {
 				.aggregation	= true,
 				.rx = {
 					.buffer_size	= 8192,
+					.aggr_time_limit = 500,
 					.aggr_close_eof	= true,
 				},
 			},

drivers/net/ipa/ipa_data-v4.5.c

@@ -97,6 +97,7 @@ static const struct ipa_gsi_endpoint_data ipa_gsi_endpoint_data[] = {
 				.rx = {
 					.buffer_size	= 8192,
 					.pad_align	= ilog2(sizeof(u32)),
+					.aggr_time_limit = 500,
 				},
 			},
 		},
@@ -144,6 +145,7 @@ static const struct ipa_gsi_endpoint_data ipa_gsi_endpoint_data[] = {
 				.aggregation	= true,
 				.rx = {
 					.buffer_size	= 8192,
+					.aggr_time_limit = 500,
 					.aggr_close_eof	= true,
 				},
 			},

drivers/net/ipa/ipa_data-v4.9.c

@@ -89,6 +89,7 @@ static const struct ipa_gsi_endpoint_data ipa_gsi_endpoint_data[] = {
 				.rx = {
 					.buffer_size	= 8192,
 					.pad_align	= ilog2(sizeof(u32)),
+					.aggr_time_limit = 500,
 				},
 			},
 		},
@@ -136,6 +137,7 @@ static const struct ipa_gsi_endpoint_data ipa_gsi_endpoint_data[] = {
 				.aggregation	= true,
 				.rx = {
 					.buffer_size	= 8192,
+					.aggr_time_limit = 500,
 					.aggr_close_eof	= true,
 				},
 			},

drivers/net/ipa/ipa_endpoint.c

@@ -35,7 +35,6 @@
 #define IPA_ENDPOINT_QMAP_METADATA_MASK		0x000000ff /* host byte order */
 
 #define IPA_ENDPOINT_RESET_AGGR_RETRY_MAX	3
-#define IPA_AGGR_TIME_LIMIT			500	/* microseconds */
 
 /** enum ipa_status_opcode - status element opcode hardware values */
 enum ipa_status_opcode {
@@ -142,6 +141,13 @@ static bool ipa_endpoint_data_valid_one(struct ipa *ipa, u32 count,
 			bool result = true;
 
 			/* No aggregation; check for bogus aggregation data */
+			if (rx_config->aggr_time_limit) {
+				dev_err(dev,
+					"time limit with no aggregation for RX endpoint %u\n",
+					data->endpoint_id);
+				result = false;
+			}
+
 			if (rx_config->aggr_hard_limit) {
 				dev_err(dev, "hard limit with no aggregation for RX endpoint %u\n",
 					data->endpoint_id);
@@ -722,9 +728,13 @@ static u32 aggr_time_limit_encoded(enum ipa_version version, u32 limit)
 
 	if (version < IPA_VERSION_4_5) {
 		/* We set aggregation granularity in ipa_hardware_config() */
-		limit = DIV_ROUND_CLOSEST(limit, IPA_AGGR_GRANULARITY);
+		fmask = aggr_time_limit_fmask(true);
+		val = DIV_ROUND_CLOSEST(limit, IPA_AGGR_GRANULARITY);
+		WARN(val > field_max(fmask),
+		     "aggr_time_limit too large (%u > %u usec)\n",
+		     val, field_max(fmask) * IPA_AGGR_GRANULARITY);
 
-		return u32_encode_bits(limit, aggr_time_limit_fmask(true));
+		return u32_encode_bits(val, fmask);
 	}
 
 	/* IPA v4.5 expresses the time limit using Qtime.  The AP has
@@ -739,6 +749,9 @@ static u32 aggr_time_limit_encoded(enum ipa_version version, u32 limit)
 		/* Have to use pulse generator 1 (millisecond granularity) */
 		gran_sel = AGGR_GRAN_SEL_FMASK;
 		val = DIV_ROUND_CLOSEST(limit, 1000);
+		WARN(val > field_max(fmask),
+		     "aggr_time_limit too large (%u > %u usec)\n",
+		     limit, field_max(fmask) * 1000);
 	} else {
 		/* We can use pulse generator 0 (100 usec granularity) */
 		gran_sel = 0;
@@ -779,7 +792,7 @@ static void ipa_endpoint_init_aggr(struct ipa_endpoint *endpoint)
 						 rx_config->aggr_hard_limit);
 			val |= aggr_byte_limit_encoded(version, limit);
 
-			limit = IPA_AGGR_TIME_LIMIT;
+			limit = rx_config->aggr_time_limit;
 			val |= aggr_time_limit_encoded(version, limit);
 
 			/* AGGR_PKT_LIMIT is 0 (unlimited) */

drivers/net/ipa/ipa_endpoint.h

@@ -59,6 +59,7 @@ struct ipa_endpoint_tx {
  * struct ipa_endpoint_rx - Endpoint configuration for RX endpoints
  * @buffer_size:	requested receive buffer size (bytes)
  * @pad_align:		power-of-2 boundary to which packet payload is aligned
+ * @aggr_time_limit:	time before aggregation closes (microseconds)
  * @aggr_hard_limit:	whether aggregation closes before or after boundary
  * @aggr_close_eof:	whether aggregation closes on end-of-frame
  * @holb_drop:		whether to drop packets to avoid head-of-line blocking
@@ -74,6 +75,10 @@ struct ipa_endpoint_tx {
  * Aggregation is "open" while a buffer is being filled, and "closes" when
  * certain criteria are met.
  *
+ * A time limit can be specified to close aggregation.  Aggregation will be
+ * closed if this period passes after data is first written into a receive
+ * buffer.  If not specified, no time limit is imposed.
+ *
  * Insufficient space available in the receive buffer can close aggregation.
  * The aggregation byte limit defines the point (in units of 1024 bytes) in
  * the buffer where aggregation closes.  With a "soft" aggregation limit,
@@ -84,6 +89,7 @@ struct ipa_endpoint_tx {
 struct ipa_endpoint_rx {
 	u32 buffer_size;
 	u32 pad_align;
+	u32 aggr_time_limit;
 	bool aggr_hard_limit;
 	bool aggr_close_eof;
 	bool holb_drop;