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Message-Id: <20220922222100.2543621-3-elder@linaro.org>
Date: Thu, 22 Sep 2022 17:20:54 -0500
From: Alex Elder <elder@...aro.org>
To: davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
pabeni@...hat.com
Cc: mka@...omium.org, evgreen@...omium.org, andersson@...nel.org,
quic_cpratapa@...cinc.com, quic_avuyyuru@...cinc.com,
quic_jponduru@...cinc.com, quic_subashab@...cinc.com,
elder@...nel.org, netdev@...r.kernel.org,
linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH net-next 2/8] net: ipa: introduce ipa_qtime_val()
Create a new function ipa_qtime_val() which returns a value that
indicates what should be encoded for a register with a time field
expressed using Qtime. Use it to factor out common code in
aggr_time_limit_encoded() and hol_block_timer_qtime_val().
Rename aggr_time_limit_encoded() and hol_block_timer_qtime_val() so
their names are both verbs ending in "encode". Rename the "limit"
argument to the former to be "milliseconds" for consistency.
Signed-off-by: Alex Elder <elder@...aro.org>
---
drivers/net/ipa/ipa_endpoint.c | 80 +++++++++++++++++++---------------
1 file changed, 44 insertions(+), 36 deletions(-)
diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index fe0eb882104ee..7d91b423a1be7 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -725,17 +725,42 @@ static u32 aggr_byte_limit_encoded(enum ipa_version version, u32 limit)
return u32_encode_bits(limit, aggr_byte_limit_fmask(false));
}
+/* For IPA v4.5+, times are expressed using Qtime. The AP uses one of two
+ * pulse generators (0 and 1) to measure elapsed time. In ipa_qtime_config()
+ * they're configured to have granularity 100 usec and 1 msec, respectively.
+ *
+ * The return value is the positive or negative Qtime value to use to
+ * express the (microsecond) time provided. A positive return value
+ * means pulse generator 0 can be used; otherwise use pulse generator 1.
+ */
+static int ipa_qtime_val(u32 microseconds, u32 max)
+{
+ u32 val;
+
+ /* Use 100 microsecond granularity if possible */
+ val = DIV_ROUND_CLOSEST(microseconds, 100);
+ if (val <= max)
+ return (int)val;
+
+ /* Have to use pulse generator 1 (millisecond granularity) */
+ val = DIV_ROUND_CLOSEST(microseconds, 1000);
+ WARN_ON(val > max);
+
+ return (int)-val;
+}
+
/* Encode the aggregation timer limit (microseconds) based on IPA version */
-static u32 aggr_time_limit_encoded(enum ipa_version version, u32 limit)
+static u32 aggr_time_limit_encode(enum ipa_version version, u32 microseconds)
{
u32 gran_sel;
u32 fmask;
u32 val;
+ int ret;
if (version < IPA_VERSION_4_5) {
/* We set aggregation granularity in ipa_hardware_config() */
fmask = aggr_time_limit_fmask(true);
- val = DIV_ROUND_CLOSEST(limit, IPA_AGGR_GRANULARITY);
+ val = DIV_ROUND_CLOSEST(microseconds, IPA_AGGR_GRANULARITY);
WARN(val > field_max(fmask),
"aggr_time_limit too large (%u > %u usec)\n",
val, field_max(fmask) * IPA_AGGR_GRANULARITY);
@@ -743,23 +768,14 @@ static u32 aggr_time_limit_encoded(enum ipa_version version, u32 limit)
return u32_encode_bits(val, fmask);
}
- /* IPA v4.5 expresses the time limit using Qtime. The AP has
- * pulse generators 0 and 1 available, which were configured
- * in ipa_qtime_config() to have granularity 100 usec and
- * 1 msec, respectively. Use pulse generator 0 if possible,
- * otherwise fall back to pulse generator 1.
- */
+ /* Compute the Qtime limit value to use */
fmask = aggr_time_limit_fmask(false);
- val = DIV_ROUND_CLOSEST(limit, 100);
- if (val > field_max(fmask)) {
- /* Have to use pulse generator 1 (millisecond granularity) */
+ ret = ipa_qtime_val(microseconds, field_max(fmask));
+ if (ret < 0) {
+ val = -ret;
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) */
+ val = ret;
gran_sel = 0;
}
@@ -799,7 +815,7 @@ static void ipa_endpoint_init_aggr(struct ipa_endpoint *endpoint)
val |= aggr_byte_limit_encoded(version, limit);
limit = rx_config->aggr_time_limit;
- val |= aggr_time_limit_encoded(version, limit);
+ val |= aggr_time_limit_encode(version, limit);
/* AGGR_PKT_LIMIT is 0 (unlimited) */
@@ -825,24 +841,18 @@ static void ipa_endpoint_init_aggr(struct ipa_endpoint *endpoint)
* represents the given number of microseconds. The result
* includes both the timer value and the selected timer granularity.
*/
-static u32 hol_block_timer_qtime_val(struct ipa *ipa, u32 microseconds)
+static u32 hol_block_timer_qtime_encode(struct ipa *ipa, u32 microseconds)
{
u32 gran_sel;
u32 val;
+ int ret;
- /* IPA v4.5 expresses time limits using Qtime. The AP has
- * pulse generators 0 and 1 available, which were configured
- * in ipa_qtime_config() to have granularity 100 usec and
- * 1 msec, respectively. Use pulse generator 0 if possible,
- * otherwise fall back to pulse generator 1.
- */
- val = DIV_ROUND_CLOSEST(microseconds, 100);
- if (val > field_max(TIME_LIMIT_FMASK)) {
- /* Have to use pulse generator 1 (millisecond granularity) */
+ ret = ipa_qtime_val(microseconds, field_max(TIME_LIMIT_FMASK));
+ if (ret < 0) {
+ val = -ret;
gran_sel = GRAN_SEL_FMASK;
- val = DIV_ROUND_CLOSEST(microseconds, 1000);
} else {
- /* We can use pulse generator 0 (100 usec granularity) */
+ val = ret;
gran_sel = 0;
}
@@ -854,12 +864,10 @@ static u32 hol_block_timer_qtime_val(struct ipa *ipa, u32 microseconds)
* derived from the 19.2 MHz SoC XO clock. For older IPA versions
* each tick represents 128 cycles of the IPA core clock.
*
- * Return the encoded value that should be written to that register
- * that represents the timeout period provided. For IPA v4.2 this
- * encodes a base and scale value, while for earlier versions the
- * value is a simple tick count.
+ * Return the encoded value representing the timeout period provided
+ * that should be written to the ENDP_INIT_HOL_BLOCK_TIMER register.
*/
-static u32 hol_block_timer_val(struct ipa *ipa, u32 microseconds)
+static u32 hol_block_timer_encode(struct ipa *ipa, u32 microseconds)
{
u32 width;
u32 scale;
@@ -872,7 +880,7 @@ static u32 hol_block_timer_val(struct ipa *ipa, u32 microseconds)
return 0; /* Nothing to compute if timer period is 0 */
if (ipa->version >= IPA_VERSION_4_5)
- return hol_block_timer_qtime_val(ipa, microseconds);
+ return hol_block_timer_qtime_encode(ipa, microseconds);
/* Use 64 bit arithmetic to avoid overflow... */
rate = ipa_core_clock_rate(ipa);
@@ -920,7 +928,7 @@ static void ipa_endpoint_init_hol_block_timer(struct ipa_endpoint *endpoint,
/* This should only be changed when HOL_BLOCK_EN is disabled */
offset = IPA_REG_ENDP_INIT_HOL_BLOCK_TIMER_N_OFFSET(endpoint_id);
- val = hol_block_timer_val(ipa, microseconds);
+ val = hol_block_timer_encode(ipa, microseconds);
iowrite32(val, ipa->reg_virt + offset);
}
--
2.34.1
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