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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Bryan ODonoghue <bryan.odonoghue@linaro.org>,
        Kalle Valo <kvalo@codeaurora.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 101/846] wcn36xx: Put DXE block into reset before freeing memory
Date:   Mon, 24 Jan 2022 19:33:38 +0100
Message-Id: <20220124184104.478674494@linuxfoundation.org>
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From: Bryan O'Donoghue <bryan.odonoghue@linaro.org>

[ Upstream commit ed04ea76e69e7194f7489cebe23a32a68f39218d ]

When deiniting the DXE hardware we should reset the block to ensure there
is no spurious DMA write transaction from the downstream WCNSS to upstream
MSM at a skbuff address we will have released.

Fixes: 8e84c2582169 ("wcn36xx: mac80211 driver for Qualcomm WCN3660/WCN3680 hardware")
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211105122152.1580542-4-bryan.odonoghue@linaro.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/ath/wcn36xx/dxe.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/wireless/ath/wcn36xx/dxe.c b/drivers/net/wireless/ath/wcn36xx/dxe.c
index 017c7d78072ba..e1a35c2eadb6c 100644
--- a/drivers/net/wireless/ath/wcn36xx/dxe.c
+++ b/drivers/net/wireless/ath/wcn36xx/dxe.c
@@ -997,6 +997,8 @@ out_err_txh_ch:
 
 void wcn36xx_dxe_deinit(struct wcn36xx *wcn)
 {
+	int reg_data = 0;
+
 	/* Disable channel interrupts */
 	wcn36xx_dxe_disable_ch_int(wcn, WCN36XX_INT_MASK_CHAN_RX_H);
 	wcn36xx_dxe_disable_ch_int(wcn, WCN36XX_INT_MASK_CHAN_RX_L);
@@ -1012,6 +1014,10 @@ void wcn36xx_dxe_deinit(struct wcn36xx *wcn)
 		wcn->tx_ack_skb = NULL;
 	}
 
+	/* Put the DXE block into reset before freeing memory */
+	reg_data = WCN36XX_DXE_REG_RESET;
+	wcn36xx_dxe_write_register(wcn, WCN36XX_DXE_REG_CSR_RESET, reg_data);
+
 	wcn36xx_dxe_ch_free_skbs(wcn, &wcn->dxe_rx_l_ch);
 	wcn36xx_dxe_ch_free_skbs(wcn, &wcn->dxe_rx_h_ch);
 
-- 
2.34.1