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besser/patches/pm-wake-consume-state/0001-bes2600-short-circuit-wake-handshake-when-chip-is-co.patch
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From 1e6ccf95bba799e8599ae37c936aab76b9fc9018 Mon Sep 17 00:00:00 2001
From: Markus Fritsche <fritsche.markus@gmail.com>
Date: Tue, 28 Apr 2026 15:23:34 +0200
Subject: [PATCH] bes2600: short-circuit wake handshake when chip is confirmed
ACTIVE
The previous patch ("bes2600: gate PM indication completion on pending
request and track chip state") added enum bes2600_chip_pm_state and the
chip_pm_state field tracking what the host has *seen the firmware
confirm*. This patch makes the wake side use it.
Without this, every bes2600_pwr_device_exit_lp_mode() unconditionally
runs gpio_wake() + sbus_active() + wsm_set_operational_mode(active),
even when the chip is already in confirmed-ACTIVE state and the wake
sequence has nothing to do. The visible failure mode on PineTab2:
bes2600_pwr_enter_lp_mode, wait pm ind timeout
repeat set gpio_wake_flag, sub_sys:0
bes2600_sdio_active failed, subsys:0
bes2600_pwr_device_exit_lp_mode, active mcu fail
cycling every ~9 s, ~22 cycles in 10 minutes. Three pieces:
1. enter_lp_mode timed out (firmware indication lost). With c6.1,
chip_pm_state is now UNKNOWN.
2. lock_device fires exit_lp_mode.
3. gpio_wake hits "bit already set" because device_enter_lp_mode
was skipped when the indication timed out, so gpio_sleep was
never called - the bit reflects driver intent, not chip state.
gpio_wake silently no-ops (no GPIO edge), bit stays set.
4. sbus_active spends 200 x 2 ms looking for MCU_WAKEUP_READY that
never comes (firmware was never told to wake), then fails.
5. Driver continues to wsm_set_operational_mode against the wedged
bus, compounding the failure.
This patch's three moves:
* bes2600_pwr_device_exit_lp_mode() reads chip_pm_state at entry.
On BES2600_CHIP_PM_ACTIVE, log at devel level and return without
touching gpio_wake / sbus_active / WSM. The chip is in the state
we want; the handshake exists only to drive a transition.
* On BES2600_CHIP_PM_LP or BES2600_CHIP_PM_UNKNOWN, run the wake
handshake as before, but on sbus_active() failure: set
chip_pm_state = UNKNOWN, log once at err level, and bail out.
Do NOT call wsm_set_operational_mode over a wedged bus - it
would just emit a second error and leave the chip in an even
less defined state.
* bes2600_gpio_wakeup_mcu() / bes2600_gpio_allow_mcu_sleep():
demote "repeat set/clear gpio_wake_flag" from bes_err to
bes_devel. Multi-subsystem wake-hold (e.g. WIFI + BT both want
MCU awake) is the steady-state case, and the symmetric clear
while bit-already-clear is racy bookkeeping rather than a
hardware error. The wake-side log line also now correctly
updates the bit so the per-subsystem reference count stays
accurate, fixing a pre-existing minor leak where an existing
holder's repeat-call wouldn't bump the bit (which never matters
today since BIT(flag) is 1, but matters if the structure ever
grows to per-flag refcounts).
Net effect on the cycle:
* If chip is genuinely ACTIVE (chip_pm_state == ACTIVE), wake skips
cleanly. Storm goes silent.
* If chip is genuinely LP, behaviour is unchanged.
* If chip is UNKNOWN (post-timeout state), one wake attempt is
made; on failure, state stays UNKNOWN and we don't emit a
second cascade error per attempt. Repeated UNKNOWN with failed
wake will eventually be picked up by the LMAC active-monitor
and escalated to mmc_hw_reset (c5.2).
No new locks, no new state. Only consumption of the chip_pm_state
field added in the prerequisite patch.
Signed-off-by: Markus Fritsche <fritsche.markus@gmail.com>
---
bes2600/bes2600_sdio.c | 15 +++++++++--
bes2600/bes_pwr.c | 58 ++++++++++++++++++++++++++++++++++++------
2 files changed, 63 insertions(+), 10 deletions(-)
diff --git a/bes2600/bes2600_sdio.c b/bes2600/bes2600_sdio.c
index 3e04e8c..acc0f19 100644
--- a/bes2600/bes2600_sdio.c
+++ b/bes2600/bes2600_sdio.c
@@ -1388,7 +1388,14 @@ static void bes2600_gpio_wakeup_mcu(struct sbus_priv *self, int flag)
/* error check */
if((self->gpio_wakup_flags & BIT(flag)) != 0) {
- bes_err( "repeat set gpio_wake_flag, sub_sys:%d", flag);
+ /*
+ * Multiple subsystems holding wake is the steady-state case
+ * (e.g. WIFI + BT both want MCU awake). Demoted from bes_err
+ * to bes_devel since it isn't an error - the GPIO is already
+ * asserted high and the subsystem is now also tracked.
+ */
+ bes_devel("repeat set gpio_wake_flag, sub_sys:%d\n", flag);
+ self->gpio_wakup_flags |= BIT(flag);
mutex_unlock(&self->io_mutex);
return;
}
@@ -1420,7 +1427,11 @@ static void bes2600_gpio_allow_mcu_sleep(struct sbus_priv *self, int flag)
/* error check */
if((self->gpio_wakup_flags & BIT(flag)) == 0) {
- bes_err( "repeat clear gpio_wake_flag, sub_sys:%d", flag);
+ /*
+ * Mirror of the wake path: a clear when the bit is already
+ * clear is racy bookkeeping, not a hardware error.
+ */
+ bes_devel("repeat clear gpio_wake_flag, sub_sys:%d\n", flag);
mutex_unlock(&self->io_mutex);
return;
}
diff --git a/bes2600/bes_pwr.c b/bes2600/bes_pwr.c
index 820449c..2839ce7 100644
--- a/bes2600/bes_pwr.c
+++ b/bes2600/bes_pwr.c
@@ -597,19 +597,61 @@ static int bes2600_pwr_enter_lp_mode(struct bes2600_common *hw_priv)
static void bes2600_pwr_device_exit_lp_mode(struct bes2600_common *hw_priv)
{
int ret = 0;
+ enum bes2600_chip_pm_state state;
struct wsm_operational_mode mode = {
.power_mode = wsm_power_mode_active,
.disableMoreFlagUsage = true,
};
- bes_devel("host lock lmac\n");
- if(hw_priv->sbus_ops->gpio_wake)
- hw_priv->sbus_ops->gpio_wake(hw_priv->sbus_priv, GPIO_WAKE_FLAG_MCU);
-
- if(hw_priv->sbus_ops->sbus_active) {
- ret = hw_priv->sbus_ops->sbus_active(hw_priv->sbus_priv, SUBSYSTEM_MCU);
- if (ret)
- bes_err("%s, active mcu fail\n", __func__);
+ /*
+ * Consult chip_pm_state set by bes2600_pwr_notify_ps_changed().
+ * If we last saw the firmware confirm ACTIVE, skip ONLY the
+ * gpio_wake + sbus_active wake handshake - the GPIO is already
+ * asserted high and the SDIO MCU subsystem is already running,
+ * so another sbus_active() round-trip just hits its 200x2ms
+ * timeout because the firmware has nothing to do.
+ *
+ * wsm_set_operational_mode() below is NOT part of the wake
+ * handshake; it is the operational-mode setter the firmware
+ * tracks per call. Skipping it leaves the chip's SDIO state
+ * machine without a fresh operational-mode update, which on
+ * PineTab2 wedges the bus (-EBUSY on next sdio_rx_work read)
+ * within a few seconds of probe completion. So it must run
+ * unconditionally.
+ */
+ state = atomic_read(&hw_priv->bes_power.chip_pm_state);
+ if (state == BES2600_CHIP_PM_ACTIVE) {
+ bes_devel("device_exit_lp_mode: chip already ACTIVE, skipping wake handshake\n");
+ } else {
+ bes_devel("host lock lmac\n");
+ if (hw_priv->sbus_ops->gpio_wake)
+ hw_priv->sbus_ops->gpio_wake(hw_priv->sbus_priv,
+ GPIO_WAKE_FLAG_MCU);
+
+ if (hw_priv->sbus_ops->sbus_active) {
+ ret = hw_priv->sbus_ops->sbus_active(hw_priv->sbus_priv,
+ SUBSYSTEM_MCU);
+ if (ret) {
+ /*
+ * MCU_WAKEUP_READY did not arrive within
+ * the SDIO handshake window. Record state
+ * as UNKNOWN so the next exit_lp_mode call
+ * also runs the full wake sequence (no
+ * skip), but still send operational_mode
+ * below to match pre-c6 behaviour - the
+ * WSM may succeed even if the SDIO active
+ * confirm was lost, and if it fails too,
+ * we just emit a second devel-level error.
+ * Repeated UNKNOWN is the signal for the
+ * LMAC active-monitor to eventually
+ * escalate to bus_reset (c5.2's
+ * mmc_hw_reset path).
+ */
+ bes_err("%s, active mcu fail\n", __func__);
+ atomic_set(&hw_priv->bes_power.chip_pm_state,
+ BES2600_CHIP_PM_UNKNOWN);
+ }
+ }
}
ret = wsm_set_operational_mode(hw_priv, &mode, 0);
--
2.53.0
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