[PATCH net v2 2/6] net: stmmac: selftests: Validate EEE based on the actual LPI timer value
From: Maxime Chevallier <maxime.chevallier@bootlin.com>
Date: 2026-09-10 15:14:38
Also in:
linux-arm-kernel, lkml
Subsystem:
networking drivers, stmmac ethernet driver, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Maxime Chevallier, Linus Torvalds
The EEE selftest is a 2-step test :
- It validates that we enter in LPI mode with the
irq_tx_path_in_lpi_mode_n counter
- It then validates that we exit LPI when sending a frame, with the
irq_tx_path_exit_lpi_mode_n counter.
The current state of the test lacks 2 main things :
- We don't know exactly when was the previous frame sent (it's from the
previous selftest)
- The timeout is hardcoded, while the LPI is entered after a
user-configurable delay. On top of that, the timeout loop uses a
pre-decrement iterator (--retries) that actually only iterate nine
times, so 900ms while the default LPI value is 1 second.
Let's therefore make it more deterministic :
- Send a frame at the beginning of the test
- Wait for more than the lpi timer value, we timeout after about twice
the value,
- Then send another frame, and verify that we do go out of LPI, also
with a timeout.
Note that the test's goal isn't to validate the LPI timer value itself,
only that we enter/leave LPI mode.
Fixes: 091810dbded9 ("net: stmmac: Introduce selftests support")
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
.../stmicro/stmmac/stmmac_selftests.c | 39 +++++++++++++++----
1 file changed, 32 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
index 6503678b646e..a8280834185c 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c@@ -462,7 +462,7 @@ static int stmmac_test_mmc(struct stmmac_priv *priv) static int stmmac_test_eee(struct stmmac_priv *priv) { struct stmmac_extra_stats *initial, *final; - int retries = 10; + unsigned long timeout, max_duration; int ret; if (!priv->dma_cap.eee || !priv->eee_active)
@@ -478,14 +478,21 @@ static int stmmac_test_eee(struct stmmac_priv *priv) goto out_free_initial; } + /* Snapshot stats, we want to count the in_lpi events. We may enter + * LPI just after the packet was sent. + */ memcpy(initial, &priv->xstats, sizeof(*initial)); + /* Send a frame, then wait to enter LPI */ ret = stmmac_test_mac_loopback(priv); if (ret) goto out_free_final; + max_duration = usecs_to_jiffies(2 * priv->tx_lpi_timer); + /* We have no traffic in the line so, sooner or later it will go LPI */ - while (--retries) { + timeout = jiffies + max_duration; + while (!time_after(jiffies, timeout)) { memcpy(final, &priv->xstats, sizeof(*final)); if (final->irq_tx_path_in_lpi_mode_n >
@@ -494,20 +501,38 @@ static int stmmac_test_eee(struct stmmac_priv *priv) msleep(100); } - if (!retries) { + memcpy(final, &priv->xstats, sizeof(*final)); + if (final->irq_tx_path_in_lpi_mode_n <= + initial->irq_tx_path_in_lpi_mode_n) { ret = -ETIMEDOUT; goto out_free_final; } - if (final->irq_tx_path_in_lpi_mode_n <= - initial->irq_tx_path_in_lpi_mode_n) { - ret = -EINVAL; + /* Re-snapshot, as we want to measure exit_lpi events. We should be + * in LPI right now. + */ + memcpy(initial, &priv->xstats, sizeof(*initial)); + + /* TX something so we go out of LPI */ + ret = stmmac_test_mac_loopback(priv); + if (ret) goto out_free_final; + + /* Wait for the exit LPI interrupt */ + timeout = jiffies + max_duration; + while (!time_after(jiffies, timeout)) { + memcpy(final, &priv->xstats, sizeof(*final)); + + if (final->irq_tx_path_exit_lpi_mode_n > + initial->irq_tx_path_exit_lpi_mode_n) + break; + msleep(100); } + memcpy(final, &priv->xstats, sizeof(*final)); if (final->irq_tx_path_exit_lpi_mode_n <= initial->irq_tx_path_exit_lpi_mode_n) { - ret = -EINVAL; + ret = -ETIMEDOUT; goto out_free_final; }
--
2.55.0