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From:   Alex Elder <elder@linaro.org>
To:     davem@davemloft.net, kuba@kernel.org
Cc:     robh+dt@kernel.org, angelogioacchino.delregno@somainline.org,
        jamipkettunen@gmail.com, bjorn.andersson@linaro.org,
        agross@kernel.org, elder@kernel.org, linux-arm-msm@vger.kernel.org,
        netdev@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH net-next 4/6] net: ipa: FLAVOR_0 register doesn't exist until IPA v3.5
Date:   Mon, 21 Jun 2021 12:56:25 -0500
Message-Id: <20210621175627.238474-5-elder@linaro.org>
In-Reply-To: <20210621175627.238474-1-elder@linaro.org>
References: <20210621175627.238474-1-elder@linaro.org>
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The FLAVOR_0 version first appears in IPA v3.5, so avoid attempting
to read it for versions prior to that.

This register contains a concise definition of the number and
direction of endpoints supported by the hardware, and without it
we can't verify endpoint configuration in ipa_endpoint_config().
In this case, just indicate that any endpoint number is available
for use.

Originally proposed by AngeloGioacchino Del Regno.

Link: https://lore.kernel.org/netdev/20210211175015.200772-3-angelogioacchino.delregno@somainline.org
Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/ipa_endpoint.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index 3520852936ed1..ab02669bae4e6 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -1731,6 +1731,21 @@ int ipa_endpoint_config(struct ipa *ipa)
 	u32 max;
 	u32 val;
 
+	/* Prior to IPAv3.5, the FLAVOR_0 register was not supported.
+	 * Furthermore, the endpoints were not grouped such that TX
+	 * endpoint numbers started with 0 and RX endpoints had numbers
+	 * higher than all TX endpoints, so we can't do the simple
+	 * direction check used for newer hardware below.
+	 *
+	 * For hardware that doesn't support the FLAVOR_0 register,
+	 * just set the available mask to support any endpoint, and
+	 * assume the configuration is valid.
+	 */
+	if (ipa->version < IPA_VERSION_3_5) {
+		ipa->available = ~0;
+		return 0;
+	}
+
 	/* Find out about the endpoints supplied by the hardware, and ensure
 	 * the highest one doesn't exceed the number we support.
 	 */
-- 
2.27.0