From: Akhil R <akhilrajeev@nvidia.com>
To: <andi.shyti@kernel.org>, <robh@kernel.org>, <krzk+dt@kernel.org>,
<onor+dt@kernel.org>, <thierry.reding@gmail.com>,
<jonathanh@nvidia.com>, <ldewangan@nvidia.com>,
<digetx@gmail.com>, <p.zabel@pengutronix.de>,
<linux-i2c@vger.kernel.org>, <devicetree@vger.kernel.org>,
<linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Cc: Akhil R <akhilrajeev@nvidia.com>, Robin Murphy <robin.murphy@arm.com>
Subject: [PATCH v2 3/3] i2c: tegra: Remove dma_sync_*() calls
Date: Fri, 16 May 2025 18:13:49 +0530 [thread overview]
Message-ID: <20250516124349.58318-3-akhilrajeev@nvidia.com> (raw)
In-Reply-To: <20250516124349.58318-1-akhilrajeev@nvidia.com>
Calling dma_sync_*() on a buffer from dma_alloc_coherent() is pointless.
The driver should not be doing its own bounce-buffering if the buffer is
allocated through dma_alloc_coherent()
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
---
v1->v2: No changes
Related thread - https://lore.kernel.org/all/acdbf49c-1a73-a0b9-a10d-42d544be3117@arm.com/
drivers/i2c/busses/i2c-tegra.c | 20 +-------------------
1 file changed, 1 insertion(+), 19 deletions(-)
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 22ddbae9d847..b10a4bc9cb34 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1292,17 +1292,9 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
if (i2c_dev->dma_mode) {
if (i2c_dev->msg_read) {
- dma_sync_single_for_device(i2c_dev->dma_dev,
- i2c_dev->dma_phys,
- xfer_size, DMA_FROM_DEVICE);
-
err = tegra_i2c_dma_submit(i2c_dev, xfer_size);
if (err)
return err;
- } else {
- dma_sync_single_for_cpu(i2c_dev->dma_dev,
- i2c_dev->dma_phys,
- xfer_size, DMA_TO_DEVICE);
}
}
@@ -1312,11 +1304,6 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
if (i2c_dev->dma_mode) {
memcpy(i2c_dev->dma_buf + I2C_PACKET_HEADER_SIZE,
msg->buf, i2c_dev->msg_len);
-
- dma_sync_single_for_device(i2c_dev->dma_dev,
- i2c_dev->dma_phys,
- xfer_size, DMA_TO_DEVICE);
-
err = tegra_i2c_dma_submit(i2c_dev, xfer_size);
if (err)
return err;
@@ -1357,13 +1344,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
return -ETIMEDOUT;
}
- if (i2c_dev->msg_read && i2c_dev->msg_err == I2C_ERR_NONE) {
- dma_sync_single_for_cpu(i2c_dev->dma_dev,
- i2c_dev->dma_phys,
- xfer_size, DMA_FROM_DEVICE);
-
+ if (i2c_dev->msg_read && i2c_dev->msg_err == I2C_ERR_NONE)
memcpy(i2c_dev->msg_buf, i2c_dev->dma_buf, i2c_dev->msg_len);
- }
}
time_left = tegra_i2c_wait_completion(i2c_dev, &i2c_dev->msg_complete,
--
2.43.2
next prev parent reply other threads:[~2025-05-16 12:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-16 12:43 [PATCH v2 1/3] dt-bindings: i2c: Add required properties Akhil R
2025-05-16 12:43 ` [PATCH v2 2/3] i2c: tegra: make reset an optional property Akhil R
2025-05-16 12:43 ` Akhil R [this message]
2025-05-16 12:53 ` [PATCH v2 1/3] dt-bindings: i2c: Add required properties Krzysztof Kozlowski
2025-05-16 13:59 ` Jon Hunter
2025-05-26 5:29 ` Akhil R
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