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FAILED: patch "[PATCH] i2c: stm32f7: unmap DMA mapped buffer" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Jul 21, 2025

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Stable branch Arm STM32 I2C subsystem host drivers ST STM32 I2C/smbus driver
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The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 6aae87fe7f180cd93a74466cdb6cf2aa9bb28798
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025072107-provolone-sagging-274b@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6aae87fe7f180cd93a74466cdb6cf2aa9bb28798 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Le=20Goffic?= <[email protected]>
Date: Fri, 4 Jul 2025 10:39:15 +0200
Subject: [PATCH] i2c: stm32f7: unmap DMA mapped buffer
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Before each I2C transfer using DMA, the I2C buffer is DMA'pped to make sure the memory buffer is DMA'able. This is handle in the function stm32_i2c_prep_dma_xfer().
If the transfer fails for any reason the I2C buffer must be unmap. Use the dma_callback to factorize the code and fix this issue.

Note that the stm32f7_i2c_dma_callback() is now called in case of DMA transfer success and error and that the complete() on the dma_complete completion structure is done inconditionnally in case of transfer success or error as well as the dmaengine_terminate_async(). This is allowed as a complete() in case transfer error has no effect as well as a dmaengine_terminate_async() on a transfer success.

Also fix the unneeded cast and remove not more needed variables.

Fixes 7ecc8cfde553 ("i2c: i2c-stm32f7: Add DMA support")
Signed-off-by Clément Le Goffic <[email protected]>
Cc <[email protected]> # v4.18+
Acked-by Alain Volmat <[email protected]>
Signed-off-by Andi Shyti <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
drivers/i2c/busses/i2c-stm32f7.c +7 -13
index 817d081460c2..73a7b8894c0d 100644
@@ -739,10 +739,11 @@ static void stm32f7_i2c_disable_dma_req(struct stm32f7_i2c_dev *i2c_dev)
 
 static void stm32f7_i2c_dma_callback(void *arg)
 {
-	struct stm32f7_i2c_dev *i2c_dev = (struct stm32f7_i2c_dev *)arg;
+	struct stm32f7_i2c_dev *i2c_dev = arg;
 	struct stm32_i2c_dma *dma = i2c_dev->dma;
 
 	stm32f7_i2c_disable_dma_req(i2c_dev);
+	dmaengine_terminate_async(dma->chan_using);
 	dma_unmap_single(i2c_dev->dev, dma->dma_buf, dma->dma_len,
 			 dma->dma_data_dir);
 	complete(&dma->dma_complete);

@@ -1510,7 +1511,6 @@ static irqreturn_t stm32f7_i2c_handle_isr_errs(struct stm32f7_i2c_dev *i2c_dev,
 	u16 addr = f7_msg->addr;
 	void __iomem *base = i2c_dev->base;
 	struct device *dev = i2c_dev->dev;
-	struct stm32_i2c_dma *dma = i2c_dev->dma;
 
 	/* Bus error */
 	if (status & STM32F7_I2C_ISR_BERR) {

@@ -1551,10 +1551,8 @@ static irqreturn_t stm32f7_i2c_handle_isr_errs(struct stm32f7_i2c_dev *i2c_dev,
 	}
 
 	/* Disable dma */
-	if (i2c_dev->use_dma) {
-		stm32f7_i2c_disable_dma_req(i2c_dev);
-		dmaengine_terminate_async(dma->chan_using);
-	}
+	if (i2c_dev->use_dma)
+		stm32f7_i2c_dma_callback(i2c_dev);
 
 	i2c_dev->master_mode = false;
 	complete(&i2c_dev->complete);

@@ -1600,7 +1598,6 @@ static irqreturn_t stm32f7_i2c_isr_event_thread(int irq, void *data)
 {
 	struct stm32f7_i2c_dev *i2c_dev = data;
 	struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
-	struct stm32_i2c_dma *dma = i2c_dev->dma;
 	void __iomem *base = i2c_dev->base;
 	u32 status, mask;
 	int ret;

@@ -1619,10 +1616,8 @@ static irqreturn_t stm32f7_i2c_isr_event_thread(int irq, void *data)
 		dev_dbg(i2c_dev->dev, "<%s>: Receive NACK (addr %x)\n",
 			__func__, f7_msg->addr);
 		writel_relaxed(STM32F7_I2C_ICR_NACKCF, base + STM32F7_I2C_ICR);
-		if (i2c_dev->use_dma) {
-			stm32f7_i2c_disable_dma_req(i2c_dev);
-			dmaengine_terminate_async(dma->chan_using);
-		}
+		if (i2c_dev->use_dma)
+			stm32f7_i2c_dma_callback(i2c_dev);
 		f7_msg->result = -ENXIO;
 	}
 

@@ -1640,8 +1635,7 @@ static irqreturn_t stm32f7_i2c_isr_event_thread(int irq, void *data)
 			ret = wait_for_completion_timeout(&i2c_dev->dma->dma_complete, HZ);
 			if (!ret) {
 				dev_dbg(i2c_dev->dev, "<%s>: Timed out\n", __func__);
-				stm32f7_i2c_disable_dma_req(i2c_dev);
-				dmaengine_terminate_async(dma->chan_using);
+				stm32f7_i2c_dma_callback(i2c_dev);
 				f7_msg->result = -ETIMEDOUT;
 			}
 		}