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From:   Christian Marangi <ansuelsmth@gmail.com>
To:     Felix Fietkau <nbd@nbd.name>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        Ryder Lee <ryder.lee@mediatek.com>,
        Shayne Chen <shayne.chen@mediatek.com>,
        Sean Wang <sean.wang@mediatek.com>,
        Kalle Valo <kvalo@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        Christian Marangi <ansuelsmth@gmail.com>,
        Simon Horman <horms@kernel.org>,
        Alexander Couzens <lynxis@fe80.eu>,
        Nicolas Cavallari <nicolas.cavallari@green-communications.fr>,
        Daniel Golle <daniel@makrotopia.org>,
        linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org
Cc:     stable@vger.kernel.org
Subject: [net-next RFC PATCH 1/6] wifi: mt76: fix broken precal loading from MTD for mt7915
Date:   Tue, 17 Oct 2023 21:05:05 +0200
Message-Id: <20231017190510.27163-1-ansuelsmth@gmail.com>
MIME-Version: 1.0
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Precedence: bulk

Commit 495184ac91bb ("mt76: mt7915: add support for applying
pre-calibration data") was fundamentally broken and never worked.

The idea (before NVMEM support) was to expand the MTD function and pass
an additional offset. For normal EEPROM load the offset would always be
0. For the purpose of precal loading, an offset was passed that was
internally the size of EEPROM, since precal data is right after the
EEPROM.

Problem is that the offset value passed is never handled and is actually
overwrite by

	offset = be32_to_cpup(list);
	ret = mtd_read(mtd, offset, len, &retlen, eep);

resulting in the passed offset value always ingnored. (and even passing
garbage data as precal as the start of the EEPROM is getting read)

Fix this by adding to the current offset value, the offset from DT to
correctly read the piece of data at the requested location.

Cc: stable@vger.kernel.org
Fixes: 495184ac91bb ("mt76: mt7915: add support for applying pre-calibration data")
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/wireless/mediatek/mt76/eeprom.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/eeprom.c b/drivers/net/wireless/mediatek/mt76/eeprom.c
index 36564930aef1..2558788f7ffb 100644
--- a/drivers/net/wireless/mediatek/mt76/eeprom.c
+++ b/drivers/net/wireless/mediatek/mt76/eeprom.c
@@ -67,7 +67,7 @@ static int mt76_get_of_epprom_from_mtd(struct mt76_dev *dev, void *eep, int offs
 		goto out_put_node;
 	}
 
-	offset = be32_to_cpup(list);
+	offset += be32_to_cpup(list);
 	ret = mtd_read(mtd, offset, len, &retlen, eep);
 	put_mtd_device(mtd);
 	if (mtd_is_bitflip(ret))
-- 
2.40.1