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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, Robin Reckmann <robin.reckmann@gmail.com>,
        Luca Weiss <luca.weiss@fairphone.com>,
        Caleb Connolly <caleb@connolly.tech>,
        Konrad Dybcio <konrad.dybcio@somainline.org>,
        Wolfram Sang <wsa@kernel.org>
Subject: [PATCH 5.19 156/365] i2c: qcom-geni: Fix GPI DMA buffer sync-back
Date:   Tue, 23 Aug 2022 10:00:57 +0200
Message-Id: <20220823080124.756891054@linuxfoundation.org>
In-Reply-To: <20220823080118.128342613@linuxfoundation.org>
References: <20220823080118.128342613@linuxfoundation.org>
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From: Robin Reckmann <robin.reckmann@googlemail.com>

commit 8689b80b22dbf1f5e993233370fe57f08731b14d upstream.

Fix i2c transfers using GPI DMA mode for all message types that do not set
the I2C_M_DMA_SAFE flag (e.g. SMBus "read byte").

In this case a bounce buffer is returned by i2c_get_dma_safe_msg_buf(),
and it has to synced back to the message after the transfer is done.

Add missing assignment of dma buffer in geni_i2c_gpi().

Set xferred in i2c_put_dma_safe_msg_buf() to true in case of no error to
ensure the sync-back of this dma buffer to the message.

Fixes: d8703554f4de ("i2c: qcom-geni: Add support for GPI DMA")
Signed-off-by: Robin Reckmann <robin.reckmann@gmail.com>
Tested-by: Luca Weiss <luca.weiss@fairphone.com>
Tested-by: Caleb Connolly <caleb@connolly.tech>
Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/i2c/busses/i2c-qcom-geni.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/i2c/busses/i2c-qcom-geni.c
+++ b/drivers/i2c/busses/i2c-qcom-geni.c
@@ -484,12 +484,12 @@ static void geni_i2c_gpi_unmap(struct ge
 {
 	if (tx_buf) {
 		dma_unmap_single(gi2c->se.dev->parent, tx_addr, msg->len, DMA_TO_DEVICE);
-		i2c_put_dma_safe_msg_buf(tx_buf, msg, false);
+		i2c_put_dma_safe_msg_buf(tx_buf, msg, !gi2c->err);
 	}
 
 	if (rx_buf) {
 		dma_unmap_single(gi2c->se.dev->parent, rx_addr, msg->len, DMA_FROM_DEVICE);
-		i2c_put_dma_safe_msg_buf(rx_buf, msg, false);
+		i2c_put_dma_safe_msg_buf(rx_buf, msg, !gi2c->err);
 	}
 }
 
@@ -553,6 +553,7 @@ static int geni_i2c_gpi(struct geni_i2c_
 	desc->callback_param = gi2c;
 
 	dmaengine_submit(desc);
+	*buf = dma_buf;
 	*dma_addr_p = addr;
 
 	return 0;