From 8a0b899f169d6b6102918327d026922140194fff Mon Sep 17 00:00:00 2001
From: Baochen Qiang <bqiang@codeaurora.org>
Date: Tue, 28 Sep 2021 14:00:44 +0300
Subject: [PATCH] ath11k: Fix inaccessible debug registers
Git-commit: 8a0b899f169d6b6102918327d026922140194fff
Patch-mainline: v5.16-rc1
References: bsc#1206451

Current code clears debug registers after SOC global reset performed
in ath11k_pci_sw_reset. However at that time those registers are
not accessible due to reset, thus they are actually not cleared at all.
For WCN6855, it may cause target fail to initialize. This issue can be
fixed by moving clear action ahead.

In addition, on some specific platforms, need to add delay to wait
those registers to become accessible.

Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-01720.1-QCAHSPSWPL_V1_V2_SILICONZ_LITE-1

Signed-off-by: Baochen Qiang <bqiang@codeaurora.org>
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210913180246.193388-3-jouni@codeaurora.org
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/wireless/ath/ath11k/pci.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath11k/pci.c b/drivers/net/wireless/ath/ath11k/pci.c
index 5abb38cc3b55..7b3bce0ba76e 100644
--- a/drivers/net/wireless/ath/ath11k/pci.c
+++ b/drivers/net/wireless/ath/ath11k/pci.c
@@ -430,6 +430,8 @@ static void ath11k_pci_force_wake(struct ath11k_base *ab)
 
 static void ath11k_pci_sw_reset(struct ath11k_base *ab, bool power_on)
 {
+	mdelay(100);
+
 	if (power_on) {
 		ath11k_pci_enable_ltssm(ab);
 		ath11k_pci_clear_all_intrs(ab);
@@ -439,9 +441,9 @@ static void ath11k_pci_sw_reset(struct ath11k_base *ab, bool power_on)
 	}
 
 	ath11k_mhi_clear_vector(ab);
+	ath11k_pci_clear_dbg_registers(ab);
 	ath11k_pci_soc_global_reset(ab);
 	ath11k_mhi_set_mhictrl_reset(ab);
-	ath11k_pci_clear_dbg_registers(ab);
 }
 
 int ath11k_pci_get_msi_irq(struct device *dev, unsigned int vector)
-- 
2.35.3