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spi: spi-mem: add statistics support to ->exec_op() calls

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Current behavior is that spi-mem operations do not increment statistics,
neither per-controller nor per-device, if ->exec_op() is used. For
operations that do NOT use ->exec_op(), stats are increased as the
usual spi_sync() is called.

The newly implemented spi_mem_add_op_stats() function is strongly
inspired by spi_statistics_add_transfer_stats(); locking logic and
l2len computation comes from there.

Statistics that are being filled: bytes{,_rx,_tx}, messages, transfers,
errors, timedout, transfer_bytes_histo_*.

Note about messages & transfers counters: in the fallback to spi_sync()
case, there are from 1 to 4 transfers per message. We only register one
big transfer in the ->exec_op() case as that is closer to reality.

This patch is NOT touching:
 - spi_async, spi_sync, spi_sync_immediate: those counters describe
   precise function calls, incrementing them would be lying. I believe
   comparing the messages counter to spi_async+spi_sync is a good way
   to detect ->exec_op() calls, but I might be missing edge cases
   knowledge.
 - transfers_split_maxsize: splitting cannot happen if ->exec_op() is
   provided.

Reviewed-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://msgid.link/r/20240216-spi-mem-stats-v2-1-9256dfe4887d@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Théo Lebrun 2024-02-16 17:42:19 +01:00 committed by Mark Brown
parent 0f3841a5e1
commit e63aef9c91
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GPG Key ID: 24D68B725D5487D0
1 changed files with 48 additions and 1 deletions
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49
drivers/spi/spi-mem.c
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@ -297,6 +297,49 @@ static void spi_mem_access_end(struct spi_mem *mem)
pm_runtime_put(ctlr->dev.parent);
}
static void spi_mem_add_op_stats(struct spi_statistics __percpu *pcpu_stats,
const struct spi_mem_op *op, int exec_op_ret)
{
struct spi_statistics *stats;
u64 len, l2len;
get_cpu();
stats = this_cpu_ptr(pcpu_stats);
u64_stats_update_begin(&stats->syncp);
/*
* We do not have the concept of messages or transfers. Let's consider
* that one operation is equivalent to one message and one transfer.
*/
u64_stats_inc(&stats->messages);
u64_stats_inc(&stats->transfers);
/* Use the sum of all lengths as bytes count and histogram value. */
len = op->cmd.nbytes + op->addr.nbytes;
len += op->dummy.nbytes + op->data.nbytes;
u64_stats_add(&stats->bytes, len);
l2len = min(fls(len), SPI_STATISTICS_HISTO_SIZE) - 1;
u64_stats_inc(&stats->transfer_bytes_histo[l2len]);
/* Only account for data bytes as transferred bytes. */
if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_OUT)
u64_stats_add(&stats->bytes_tx, op->data.nbytes);
if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_IN)
u64_stats_add(&stats->bytes_rx, op->data.nbytes);
/*
* A timeout is not an error, following the same behavior as
* spi_transfer_one_message().
*/
if (exec_op_ret == -ETIMEDOUT)
u64_stats_inc(&stats->timedout);
else if (exec_op_ret)
u64_stats_inc(&stats->errors);
u64_stats_update_end(&stats->syncp);
put_cpu();
}
/**
* spi_mem_exec_op() - Execute a memory operation
* @mem: the SPI memory
@ -339,8 +382,12 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
* read path) and expect the core to use the regular SPI
* interface in other cases.
*/
if (!ret || ret != -ENOTSUPP || ret != -EOPNOTSUPP)
if (!ret || ret != -ENOTSUPP || ret != -EOPNOTSUPP) {
spi_mem_add_op_stats(ctlr->pcpu_statistics, op, ret);
spi_mem_add_op_stats(mem->spi->pcpu_statistics, op, ret);
return ret;
}
}
tmpbufsize = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;