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From:   Ricardo Ribalda <ribalda@chromium.org>
Date:   Sun, 25 Dec 2022 09:37:12 +0100
Subject: [PATCH] spi: mediatek: Enable irq before the spi registration
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Message-Id: <20221225-mtk-spi-fixes-v1-0-bb6c14c232f8@chromium.org>
To:     Matthias Brugger <matthias.bgg@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
Cc:     linux-mediatek@lists.infradead.org,
        Ricardo Ribalda <ribalda@chromium.org>,
        linux-arm-kernel@lists.infradead.org,
        Daniel Golle <daniel@makrotopia.org>,
        linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org
Precedence: bulk

If the irq is enabled after the spi si registered, there can be a race
with the initialization of the devices on the spi bus.

Eg:
mtk-spi 1100a000.spi: spi-mem transfer timeout
spi-nor: probe of spi0.0 failed with error -110
Unable to handle kernel NULL pointer dereference at virtual address
0000000000000010
...
Call trace:
 mtk_spi_can_dma+0x0/0x2c

Fixes: c6f7874687f7 ("spi: mediatek: Enable irq when pdata is ready")
Reported-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
spi: mediatek: Fix init order (again)

Hi Mark

Here is a fixup of the previous patch. Daniel, can you confirm that it
works on your hardware? 

Thanks and sorry for annoyance. 

To: Mark Brown <broonie@kernel.org>
To: Matthias Brugger <matthias.bgg@gmail.com>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: linux-spi@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mediatek@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: Daniel Golle <daniel@makrotopia.org>
---
 drivers/spi/spi-mt65xx.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index 6de8360e5c2a..9eab6c20dbc5 100644
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -1253,6 +1253,11 @@ static int mtk_spi_probe(struct platform_device *pdev)
 		dev_notice(dev, "SPI dma_set_mask(%d) failed, ret:%d\n",
 			   addr_bits, ret);
 
+	ret = devm_request_irq(dev, irq, mtk_spi_interrupt,
+			       IRQF_TRIGGER_NONE, dev_name(dev), master);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to register irq\n");
+
 	pm_runtime_enable(dev);
 
 	ret = devm_spi_register_master(dev, master);
@@ -1261,13 +1266,6 @@ static int mtk_spi_probe(struct platform_device *pdev)
 		return dev_err_probe(dev, ret, "failed to register master\n");
 	}
 
-	ret = devm_request_irq(dev, irq, mtk_spi_interrupt,
-			       IRQF_TRIGGER_NONE, dev_name(dev), master);
-	if (ret) {
-		pm_runtime_disable(dev);
-		return dev_err_probe(dev, ret, "failed to register irq\n");
-	}
-
 	return 0;
 }
 

---
base-commit: 45b3cd900bf8d1a3cd7cf48361df8c09ae5b4009
change-id: 20221225-mtk-spi-fixes-99c863a6fdf1

Best regards,
-- 
Ricardo Ribalda <ribalda@chromium.org>