[PATCH v2] wifi: ath10k: poll service ready message before failing

[Baochen Qiang <quic_bqiang@quicinc.com>]

Currently host relies on CE interrupts to get notified that
the service ready message is ready. This results in timeout
issue if the interrupt is not fired, due to some unknown
reasons. See below logs:

[76321.937866] ath10k_pci 0000:02:00.0: wmi service ready event not received
...
[76322.016738] ath10k_pci 0000:02:00.0: Could not init core: -110

And finally it causes WLAN interface bring up failure.

Change to give it one more chance here by polling CE rings,
before failing directly.

Tested-on: QCA6174 hw3.2 PCI WLAN.RM.4.4.1-00157-QCARMSWPZ-1

Fixes: 5e3dd157d7e7 ("ath10k: mac80211 driver for Qualcomm Atheros 802.11ac CQA98xx devices")
Reported-by: James Prestwood <prestwoj@gmail.com>
Link: https://lore.kernel.org/linux-wireless/304ce305-fbe6-420e-ac2a-d61ae5e6ca1a@gmail.com/
Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
---
v2:
 - print the end result of polling.

 drivers/net/wireless/ath/ath10k/wmi.c | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/wmi.c b/drivers/net/wireless/ath/ath10k/wmi.c
index 2e9661f4bea8..80d255aaff1b 100644
--- a/drivers/net/wireless/ath/ath10k/wmi.c
+++ b/drivers/net/wireless/ath/ath10k/wmi.c
@@ -1763,12 +1763,32 @@ void ath10k_wmi_put_wmi_channel(struct ath10k *ar, struct wmi_channel *ch,
 
 int ath10k_wmi_wait_for_service_ready(struct ath10k *ar)
 {
-	unsigned long time_left;
+	unsigned long time_left, i;
 
 	time_left = wait_for_completion_timeout(&ar->wmi.service_ready,
 						WMI_SERVICE_READY_TIMEOUT_HZ);
-	if (!time_left)
-		return -ETIMEDOUT;
+	if (!time_left) {
+		/* Sometimes the PCI HIF doesn't receive interrupt
+		 * for the service ready message even if the buffer
+		 * was completed. PCIe sniffer shows that it's
+		 * because the corresponding CE ring doesn't fires
+		 * it. Workaround here by polling CE rings once.
+		 */
+		ath10k_warn(ar, "failed to receive service ready completion, polling..\n");
+
+		for (i = 0; i < CE_COUNT; i++)
+			ath10k_hif_send_complete_check(ar, i, 1);
+
+		time_left = wait_for_completion_timeout(&ar->wmi.service_ready,
+							WMI_SERVICE_READY_TIMEOUT_HZ);
+		if (!time_left) {
+			ath10k_warn(ar, "polling timed out\n");
+			return -ETIMEDOUT;
+		}
+
+		ath10k_warn(ar, "service ready completion received, continuing normally\n");
+	}
+
 	return 0;
 }
 

base-commit: c39a5cfa0448f3afbee78373f16d87815a674f11
-- 
2.25.1