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

@@ -1368,7 +1368,14 @@ 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;
 	}
@@ -1400,7 +1407,11 @@ 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;
 	}