releases/6.18.7/i2c-qcom-geni-make-sure-i2c-hub-controllers-can-t-us.patch

From 65a9c428e0e22b1fbe6d8524dbc194d57d4e335b Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Wed, 29 Oct 2025 19:07:42 +0100
Subject: i2c: qcom-geni: make sure I2C hub controllers can't use SE DMA

From: Neil Armstrong <neil.armstrong@linaro.org>

[ Upstream commit c0c50e3743e467ec4752c638e10e97f89c8644e2 ]

The I2C Hub controller is a simpler GENI I2C variant that doesn't
support DMA at all, add a no_dma flag to make sure it nevers selects
the SE DMA mode with mappable 32bytes long transfers.

Fixes: cacd9643eca7 ("i2c: qcom-geni: add support for I2C Master Hub variant")
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Mukesh Kumar Savaliya <mukesh.savaliya@oss.qualcomm.com>>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i2c/busses/i2c-qcom-geni.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
index 43fdd89b8bebc..bfb352b04902c 100644
--- a/drivers/i2c/busses/i2c-qcom-geni.c
+++ b/drivers/i2c/busses/i2c-qcom-geni.c
@@ -97,6 +97,7 @@ struct geni_i2c_dev {
 	dma_addr_t dma_addr;
 	struct dma_chan *tx_c;
 	struct dma_chan *rx_c;
+	bool no_dma;
 	bool gpi_mode;
 	bool abort_done;
 };
@@ -425,7 +426,7 @@ static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
 	size_t len = msg->len;
 	struct i2c_msg *cur;
 
-	dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
+	dma_buf = gi2c->no_dma ? NULL : i2c_get_dma_safe_msg_buf(msg, 32);
 	if (dma_buf)
 		geni_se_select_mode(se, GENI_SE_DMA);
 	else
@@ -464,7 +465,7 @@ static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
 	size_t len = msg->len;
 	struct i2c_msg *cur;
 
-	dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
+	dma_buf = gi2c->no_dma ? NULL : i2c_get_dma_safe_msg_buf(msg, 32);
 	if (dma_buf)
 		geni_se_select_mode(se, GENI_SE_DMA);
 	else
@@ -880,10 +881,12 @@ static int geni_i2c_probe(struct platform_device *pdev)
 		goto err_resources;
 	}
 
-	if (desc && desc->no_dma_support)
+	if (desc && desc->no_dma_support) {
 		fifo_disable = false;
-	else
+		gi2c->no_dma = true;
+	} else {
 		fifo_disable = readl_relaxed(gi2c->se.base + GENI_IF_DISABLE_RO) & FIFO_IF_DISABLE;
+	}
 
 	if (fifo_disable) {
 		/* FIFO is disabled, so we can only use GPI DMA */
-- 
2.51.0