[PATCH] wifi: ath11k: Defer on rproc_get failure

[Luca Weiss <luca.weiss@fairphone.com>]

If we already have gotten the rproc_handle (meaning the "qcom,rproc"
property is defined in the devicetree), it's a valid state that the
remoteproc module hasn't probed yet so we should defer probing instead
of just failing to probe.

This resolves a race condition when the ath11k driver probes and fails
before the wpss remoteproc driver has probed, like the following:

  [    6.232360] ath11k 17a10040.wifi: failed to get rproc
  [    6.232366] ath11k 17a10040.wifi: failed to get rproc: -22
  [    6.232478] ath11k: probe of 17a10040.wifi failed with error -22
       ...
  [    6.252415] remoteproc remoteproc2: 8a00000.remoteproc is available
  [    6.252776] remoteproc remoteproc2: powering up 8a00000.remoteproc
  [    6.252781] remoteproc remoteproc2: Booting fw image qcom/qcm6490/fairphone5/wpss.mdt, size 7188

So, defer the probe if we hit that so we can retry later once the wpss
remoteproc is available.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
 drivers/net/wireless/ath/ath11k/ahb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath11k/ahb.c b/drivers/net/wireless/ath/ath11k/ahb.c
index 235336ef2a7a..f8f5e653cd03 100644
--- a/drivers/net/wireless/ath/ath11k/ahb.c
+++ b/drivers/net/wireless/ath/ath11k/ahb.c
@@ -803,8 +803,8 @@ static int ath11k_core_get_rproc(struct ath11k_base *ab)
 
 	prproc = rproc_get_by_phandle(rproc_phandle);
 	if (!prproc) {
-		ath11k_err(ab, "failed to get rproc\n");
-		return -EINVAL;
+		ath11k_dbg(ab, ATH11K_DBG_AHB, "failed to get rproc, deferring\n");
+		return -EPROBE_DEFER;
 	}
 	ab_ahb->tgt_rproc = prproc;
 

---
base-commit: 2ef7141596eed0b4b45ef18b3626f428a6b0a822
change-id: 20231027-ath11k-rproc-defer-d166779fa113

Best regards,
-- 
Luca Weiss <luca.weiss@fairphone.com>