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Date: Mon, 30 Nov 2020 17:37:11 -0600 From: Alex Elder <elder@...aro.org> To: davem@...emloft.net, kuba@...nel.org Cc: evgreen@...omium.org, subashab@...eaurora.org, cpratapa@...eaurora.org, bjorn.andersson@...aro.org, netdev@...r.kernel.org, linux-kernel@...r.kernel.org Subject: [PATCH net-next 3/4] net: ipa: use Qtime for IPA v4.5 aggregation time limit Change aggr_time_limit_encoded() to properly calculate the aggregation time limit to use for IPA v4.5. Older IPA versions program the AGGR_GRANULARITY field of the of the COUNTER_CFG register to set the granularity of the aggregation timer, which we configure to be 500 microseconds. Instead, IPA v4.5 selects between two possible granularity values derived from the 19.2 MHz Qtime clock. These granularities are 100 microseconds or 1 millisecond per tick. We use the smaller granularity if possible, unless the desired period is too large to be specified that way. Signed-off-by: Alex Elder <elder@...aro.org> --- drivers/net/ipa/ipa_endpoint.c | 32 ++++++++++++++++++++++++++++---- 1 file changed, 28 insertions(+), 4 deletions(-) diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c index f260c80f50649..b4c884ccb77d2 100644 --- a/drivers/net/ipa/ipa_endpoint.c +++ b/drivers/net/ipa/ipa_endpoint.c @@ -638,14 +638,38 @@ static u32 aggr_byte_limit_encoded(enum ipa_version version, u32 limit) return u32_encode_bits(limit, aggr_byte_limit_fmask(false)); } +/* Encode the aggregation timer limit (microseconds) based on IPA version */ static u32 aggr_time_limit_encoded(enum ipa_version version, u32 limit) { - /* Convert limit (microseconds) to aggregation timer ticks */ - limit = DIV_ROUND_CLOSEST(limit, IPA_AGGR_GRANULARITY); - if (version < IPA_VERSION_4_5) + u32 gran_sel; + u32 fmask; + u32 val; + + if (version < IPA_VERSION_4_5) { + /* We set aggregation granularity in ipa_hardware_config() */ + limit = DIV_ROUND_CLOSEST(limit, IPA_AGGR_GRANULARITY); + return u32_encode_bits(limit, aggr_time_limit_fmask(true)); + } - return u32_encode_bits(limit, aggr_time_limit_fmask(false)); + /* 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. + */ + 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) */ + gran_sel = AGGR_GRAN_SEL_FMASK; + val = DIV_ROUND_CLOSEST(limit, 1000); + } else { + /* We can use pulse generator 0 (100 usec granularity) */ + gran_sel = 0; + } + + return gran_sel | u32_encode_bits(val, fmask); } static u32 aggr_sw_eof_active_encoded(enum ipa_version version, bool enabled) -- 2.20.1
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