Add a new flag for AP receive endpoints that indicates whether
a "hard limit" is used as a criterion for closing aggregation.
Add comments explaining the difference between "hard" and "soft"
aggregation limits.
Pass a flag to ipa_aggr_size_kb() so it computes the proper
aggregation size value whether using hard or soft limits. Move
that function earlier in "ipa_endpoint.c" so it can be used
without a forward-reference.
Update ipa_endpoint_data_valid_one() so it validates endpoints whose
data indicate a hard aggregation limit is used, and so it reports
set aggregation flags for endpoints without aggregation enabled.
Signed-off-by: Alex Elder <elder@xxxxxxxxxx>
---
drivers/net/ipa/ipa_endpoint.c | 89 +++++++++++++++++++++-------------
drivers/net/ipa/ipa_endpoint.h | 15 +++++-
2 files changed, 69 insertions(+), 35 deletions(-)
diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index 3ad97fbf6884e..6079670bd8605 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -81,6 +81,24 @@ static u32 aggr_byte_limit_max(enum ipa_version version)
return field_max(aggr_byte_limit_fmask(false));
}
+/* Compute the aggregation size value to use for a given buffer size */
+static u32 ipa_aggr_size_kb(u32 rx_buffer_size, bool aggr_hard_limit)
+{
+ /* A hard aggregation limit will not be crossed; aggregation closes
+ * if saving incoming data would cross the hard byte limit boundary.
+ *
+ * With a soft limit, aggregation closes *after* the size boundary
+ * has been crossed. In that case the limit must leave enough space
+ * after that limit to receive a full MTU of data plus overhead.
+ */
+ if (!aggr_hard_limit)
+ rx_buffer_size -= IPA_MTU + IPA_RX_BUFFER_OVERHEAD;
+
+ /* The byte limit is encoded as a number of kilobytes */
+
+ return rx_buffer_size / SZ_1K;
+}
+
static bool ipa_endpoint_data_valid_one(struct ipa *ipa, u32 count,
const struct ipa_gsi_endpoint_data *all_data,
const struct ipa_gsi_endpoint_data *data)
@@ -93,7 +111,9 @@ static bool ipa_endpoint_data_valid_one(struct ipa *ipa, u32 count,
return true;
if (!data->toward_ipa) {
+ const struct ipa_endpoint_rx *rx_config;
u32 buffer_size;
+ u32 aggr_size;
u32 limit;
if (data->endpoint.filter_support) {
@@ -107,8 +127,10 @@ static bool ipa_endpoint_data_valid_one(struct ipa *ipa, u32 count,
if (data->ee_id != GSI_EE_AP)
return true;
- buffer_size = data->endpoint.config.rx.buffer_size;
+ rx_config = &data->endpoint.config.rx;
+
/* The buffer size must hold an MTU plus overhead */
+ buffer_size = rx_config->buffer_size;
limit = IPA_MTU + IPA_RX_BUFFER_OVERHEAD;
if (buffer_size < limit) {
dev_err(dev, "RX buffer size too small for RX endpoint %u (%u < %u)\n",
@@ -116,27 +138,39 @@ static bool ipa_endpoint_data_valid_one(struct ipa *ipa, u32 count,
return false;
}
- /* For an endpoint supporting receive aggregation, the
- * aggregation byte limit defines the point at which an
- * aggregation window will close. It is programmed into the
- * IPA hardware as a number of KB. We don't use "hard byte
- * limit" aggregation, so we need to supply enough space in
- * a receive buffer to hold a complete MTU plus normal skb
- * overhead *after* that aggregation byte limit has been
- * crossed.
- *
- * This check just ensures the receive buffer size doesn't
- * exceed what's representable in the aggregation limit field.
+ if (!data->endpoint.config.aggregation) {
+ bool result = true;
+
+ /* No aggregation; check for bogus aggregation data */
+ if (rx_config->aggr_hard_limit) {
+ dev_err(dev, "hard limit with no aggregation for RX endpoint %u\n",
+ data->endpoint_id);
+ result = false;
+ }
+
+ if (rx_config->aggr_close_eof) {
+ dev_err(dev, "close EOF with no aggregation for RX endpoint %u\n",
+ data->endpoint_id);
+ result = false;
+ }
+
+ return result; /* Nothing more to check */
+ }
+
+ /* For an endpoint supporting receive aggregation, the byte
+ * limit defines the point at which aggregation closes. This
+ * check ensures the receive buffer size doesn't result in a
+ * limit that exceeds what's representable in the aggregation
+ * byte limit field.
*/
- if (data->endpoint.config.aggregation) {
- limit += SZ_1K * aggr_byte_limit_max(ipa->version);
- if (buffer_size - NET_SKB_PAD > limit) {
- dev_err(dev, "RX buffer size too large for aggregated RX endpoint %u (%u > %u)\n",
- data->endpoint_id,
- buffer_size - NET_SKB_PAD, limit);
+ aggr_size = ipa_aggr_size_kb(buffer_size - NET_SKB_PAD,
+ rx_config->aggr_hard_limit);
+ limit = aggr_byte_limit_max(ipa->version);
+ if (aggr_size > limit) {
+ dev_err(dev, "aggregated size too large for RX endpoint %u (%u KB > %u KB)\n",
+ data->endpoint_id, aggr_size, limit);
- return false;
- }
+ return false;
}
return true; /* Nothing more to check for RX */
@@ -670,18 +704,6 @@ static void ipa_endpoint_init_mode(struct ipa_endpoint *endpoint)
iowrite32(val, endpoint->ipa->reg_virt + offset);
}
-/* Compute the aggregation size value to use for a given buffer size */
-static u32 ipa_aggr_size_kb(u32 rx_buffer_size)
-{
- /* We don't use "hard byte limit" aggregation, so we define the
- * aggregation limit such that our buffer has enough space *after*
- * that limit to receive a full MTU of data, plus overhead.
- */
- rx_buffer_size -= IPA_MTU + IPA_RX_BUFFER_OVERHEAD;
-
- return rx_buffer_size / SZ_1K;
-}
-
/* Encoded values for AGGR endpoint register fields */
static u32 aggr_byte_limit_encoded(enum ipa_version version, u32 limit)
{
@@ -753,7 +775,8 @@ static void ipa_endpoint_init_aggr(struct ipa_endpoint *endpoint)
val |= u32_encode_bits(IPA_GENERIC, AGGR_TYPE_FMASK);
buffer_size = rx_config->buffer_size;
- limit = ipa_aggr_size_kb(buffer_size - NET_SKB_PAD);
+ limit = ipa_aggr_size_kb(buffer_size - NET_SKB_PAD,
+ rx_config->aggr_hard_limit);
val |= aggr_byte_limit_encoded(version, limit);
limit = IPA_AGGR_TIME_LIMIT;
diff --git a/drivers/net/ipa/ipa_endpoint.h b/drivers/net/ipa/ipa_endpoint.h
index 3ab62fb892ec6..1e72a9695d3d9 100644
--- a/drivers/net/ipa/ipa_endpoint.h
+++ b/drivers/net/ipa/ipa_endpoint.h
@@ -59,21 +59,32 @@ 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_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
*
+ * The actual size of the receive buffer is rounded up if necessary
+ * to be a power-of-2 number of pages.
+ *
* With each packet it transfers, the IPA hardware can perform certain
* transformations of its packet data. One of these is adding pad bytes
* to the end of the packet data so the result ends on a power-of-2 boundary.
*
* It is also able to aggregate multiple packets into a single receive buffer.
* Aggregation is "open" while a buffer is being filled, and "closes" when
- * certain criteria are met. One of those criteria is the sender indicating
- * a "frame" consisting of several transfers has ended.
+ * certain criteria are met.
+ *
+ * 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,
+ * aggregation closes when a packet written to the buffer *crosses* that
+ * aggregation limit. With a "hard" aggregation limit, aggregation will
+ * close *before* writing a packet that would cross that boundary.
*/
struct ipa_endpoint_rx {
u32 buffer_size;
u32 pad_align;
+ bool aggr_hard_limit;
bool aggr_close_eof;
bool holb_drop;
};
--
2.32.0
