From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Alex Elder <elder@linaro.org>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 073/154] net: ipa: disable HOLB drop when updating timer
Date:   Wed, 24 Nov 2021 12:57:49 +0100
Message-Id: <20211124115704.694646085@linuxfoundation.org>
In-Reply-To: <20211124115702.361983534@linuxfoundation.org>
References: <20211124115702.361983534@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Alex Elder <elder@linaro.org>

[ Upstream commit 816316cacad2b5abd5b41423cf04e4845239abd4 ]

The head-of-line blocking timer should only be modified when
head-of-line drop is disabled.

One of the steps in recovering from a modem crash is to enable
dropping of packets with timeout of 0 (immediate).  We don't know
how the modem configured its endpoints, so before we program the
timer, we need to ensure HOL_BLOCK is disabled.

Fixes: 84f9bd12d46db ("soc: qcom: ipa: IPA endpoints")
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ipa/ipa_endpoint.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -703,6 +703,7 @@ static void ipa_endpoint_init_hol_block_
 	u32 offset;
 	u32 val;
 
+	/* This should only be changed when HOL_BLOCK_EN is disabled */
 	offset = IPA_REG_ENDP_INIT_HOL_BLOCK_TIMER_N_OFFSET(endpoint_id);
 	val = ipa_reg_init_hol_block_timer_val(ipa, microseconds);
 	iowrite32(val, ipa->reg_virt + offset);
@@ -730,6 +731,7 @@ void ipa_endpoint_modem_hol_block_clear_
 		if (endpoint->toward_ipa || endpoint->ee_id != GSI_EE_MODEM)
 			continue;
 
+		ipa_endpoint_init_hol_block_enable(endpoint, false);
 		ipa_endpoint_init_hol_block_timer(endpoint, 0);
 		ipa_endpoint_init_hol_block_enable(endpoint, true);
 	}