[PATCH net-next 0/3] net: ipa: simple refactorizations

[PATCH net-next 0/3] net: ipa: simple refactorizations

[Alex Elder]

This series makes three small changes to some endpoint configuration
code.  The first uses a constant to represent the frequency of an
internal clock used for timers in the IPA.  The second modifies a
limit used so it matches Qualcomm's internal code.  And the third
reworks a few lines of code, eliminating a multi-line function call.

					-Alex

Alex Elder (3):
  net: ipa: rework ipa_aggr_granularity_val()
  net: ipa: reduce aggregation time limit
  net: ipa: reuse a local variable in ipa_endpoint_init_aggr()

 drivers/net/ipa/ipa_endpoint.c | 17 ++++++++++-------
 drivers/net/ipa/ipa_main.c     |  5 +++++
 drivers/net/ipa/ipa_reg.h      | 17 ++++++++---------
 3 files changed, 23 insertions(+), 16 deletions(-)

-- 
2.25.1

[PATCH net-next 1/3] net: ipa: rework ipa_aggr_granularity_val()

[Alex Elder]

The timer used for aggregation makes use of an internal 32 KHz clock.
The granularity of the timer is programmed by a field whose value is
computed by ipa_aggr_granularity_val().  Redefine the way that value
is computed by using a new TIMER_FREQUENCY constant representing the
underlying clock frequency.

Add two BUILD_BUG_ON() calls to ensure the value used is valid.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/ipa_main.c |  5 +++++
 drivers/net/ipa/ipa_reg.h  | 17 ++++++++---------
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ipa/ipa_main.c b/drivers/net/ipa/ipa_main.c
index 76d5108b8403..27a869df3a4b 100644
--- a/drivers/net/ipa/ipa_main.c
+++ b/drivers/net/ipa/ipa_main.c
@@ -674,6 +674,11 @@ static void ipa_validate_build(void)
 
 	/* This is used as a divisor */
 	BUILD_BUG_ON(!IPA_AGGR_GRANULARITY);
+
+	/* Aggregation granularity value can't be 0, and must fit */
+	BUILD_BUG_ON(!ipa_aggr_granularity_val(IPA_AGGR_GRANULARITY));
+	BUILD_BUG_ON(ipa_aggr_granularity_val(IPA_AGGR_GRANULARITY) >
+			field_max(AGGR_GRANULARITY));
 #endif /* IPA_VALIDATE */
 }
 
diff --git a/drivers/net/ipa/ipa_reg.h b/drivers/net/ipa/ipa_reg.h
index 0a688d8c1d7c..7ae8015798ae 100644
--- a/drivers/net/ipa/ipa_reg.h
+++ b/drivers/net/ipa/ipa_reg.h
@@ -190,24 +190,23 @@ static inline u32 ipa_reg_bcr_val(enum ipa_version version)
 	return 0x00000000;
 }
 
-
 #define IPA_REG_LOCAL_PKT_PROC_CNTXT_BASE_OFFSET	0x000001e8
 
 #define IPA_REG_AGGR_FORCE_CLOSE_OFFSET			0x000001ec
 /* ipa->available defines the valid bits in the AGGR_FORCE_CLOSE register */
 
+/* The internal inactivity timer clock is used for the aggregation timer */
+#define TIMER_FREQUENCY	32000	/* 32 KHz inactivity timer clock */
+
 #define IPA_REG_COUNTER_CFG_OFFSET			0x000001f0
 #define AGGR_GRANULARITY			GENMASK(8, 4)
-/* Compute the value to use in the AGGR_GRANULARITY field representing
- * the given number of microseconds (up to 1 millisecond).
- *	x = (32 * usec) / 1000 - 1
+/* Compute the value to use in the AGGR_GRANULARITY field representing the
+ * given number of microseconds.  The value is one less than the number of
+ * timer ticks in the requested period.  Zero not a valid granularity value.
  */
-static inline u32 ipa_aggr_granularity_val(u32 microseconds)
+static inline u32 ipa_aggr_granularity_val(u32 usec)
 {
-	/* assert(microseconds >= 16); (?) */
-	/* assert(microseconds <= 1015); */
-
-	return DIV_ROUND_CLOSEST(32 * microseconds, 1000) - 1;
+	return DIV_ROUND_CLOSEST(usec * TIMER_FREQUENCY, USEC_PER_SEC) - 1;
 }
 
 #define IPA_REG_TX_CFG_OFFSET				0x000001fc
-- 
2.25.1

[PATCH net-next 2/3] net: ipa: reduce aggregation time limit

[Alex Elder]

Halve the time limit used when aggregation is enabled on an RX
endpoint, to half a millisecond.

Use DIV_ROUND_CLOSEST() to compute the value that represents the
time period, to get better accuracy in the event the time limit is
not an even multiple of the granularity.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/ipa_endpoint.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index 9f50d0d11704..93449366d7d8 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -36,7 +36,7 @@
 #define IPA_ENDPOINT_QMAP_METADATA_MASK		0x000000ff /* host byte order */
 
 #define IPA_ENDPOINT_RESET_AGGR_RETRY_MAX	3
-#define IPA_AGGR_TIME_LIMIT_DEFAULT		1000	/* microseconds */
+#define IPA_AGGR_TIME_LIMIT_DEFAULT		500	/* microseconds */
 
 /** enum ipa_status_opcode - status element opcode hardware values */
 enum ipa_status_opcode {
@@ -583,9 +583,11 @@ static void ipa_endpoint_init_aggr(struct ipa_endpoint *endpoint)
 			val |= u32_encode_bits(IPA_GENERIC, AGGR_TYPE_FMASK);
 			val |= u32_encode_bits(aggr_size,
 					       AGGR_BYTE_LIMIT_FMASK);
+
 			limit = IPA_AGGR_TIME_LIMIT_DEFAULT;
-			val |= u32_encode_bits(limit / IPA_AGGR_GRANULARITY,
-					       AGGR_TIME_LIMIT_FMASK);
+			limit = DIV_ROUND_CLOSEST(limit, IPA_AGGR_GRANULARITY);
+			val |= u32_encode_bits(limit, AGGR_TIME_LIMIT_FMASK);
+
 			val |= u32_encode_bits(0, AGGR_PKT_LIMIT_FMASK);
 			if (endpoint->data->rx.aggr_close_eof)
 				val |= AGGR_SW_EOF_ACTIVE_FMASK;
-- 
2.25.1

[PATCH net-next 3/3] net: ipa: reuse a local variable in ipa_endpoint_init_aggr()

[Alex Elder]

Reuse the "limit" local variable in ipa_endpoint_init_aggr() when
setting the aggregation size limit.  Simple cleanup.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/ipa_endpoint.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index 93449366d7d8..2f56981b051e 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -576,19 +576,20 @@ static void ipa_endpoint_init_aggr(struct ipa_endpoint *endpoint)
 
 	if (endpoint->data->aggregation) {
 		if (!endpoint->toward_ipa) {
-			u32 aggr_size = ipa_aggr_size_kb(IPA_RX_BUFFER_SIZE);
 			u32 limit;
 
 			val |= u32_encode_bits(IPA_ENABLE_AGGR, AGGR_EN_FMASK);
 			val |= u32_encode_bits(IPA_GENERIC, AGGR_TYPE_FMASK);
-			val |= u32_encode_bits(aggr_size,
-					       AGGR_BYTE_LIMIT_FMASK);
+
+			limit = ipa_aggr_size_kb(IPA_RX_BUFFER_SIZE);
+			val |= u32_encode_bits(limit, AGGR_BYTE_LIMIT_FMASK);
 
 			limit = IPA_AGGR_TIME_LIMIT_DEFAULT;
 			limit = DIV_ROUND_CLOSEST(limit, IPA_AGGR_GRANULARITY);
 			val |= u32_encode_bits(limit, AGGR_TIME_LIMIT_FMASK);
 
-			val |= u32_encode_bits(0, AGGR_PKT_LIMIT_FMASK);
+			/* AGGR_PKT_LIMIT is 0 (unlimited) */
+
 			if (endpoint->data->rx.aggr_close_eof)
 				val |= AGGR_SW_EOF_ACTIVE_FMASK;
 			/* AGGR_HARD_BYTE_LIMIT_ENABLE is 0 */
-- 
2.25.1

Re: [PATCH net-next 0/3] net: ipa: simple refactorizations

[David Miller]

From: Alex Elder <elder@linaro.org>
Date: Mon, 29 Jun 2020 16:55:20 -0500

> This series makes three small changes to some endpoint configuration
> code.  The first uses a constant to represent the frequency of an
> internal clock used for timers in the IPA.  The second modifies a
> limit used so it matches Qualcomm's internal code.  And the third
> reworks a few lines of code, eliminating a multi-line function call.

Series applied to net-next.