public inbox for linux-i2c@vger.kernel.org
 help / color / mirror / Atom feed
From: Akhil R <akhilrajeev@nvidia.com>
To: <andi.shyti@kernel.org>, <robh@kernel.org>, <krzk+dt@kernel.org>,
	<conor+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 v3 3/3] i2c: tegra: Remove dma_sync_*() calls
Date: Mon, 26 May 2025 10:55:53 +0530	[thread overview]
Message-ID: <20250526052553.42766-3-akhilrajeev@nvidia.com> (raw)
In-Reply-To: <20250526052553.42766-1-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>
---
 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


  parent reply	other threads:[~2025-05-26  5:26 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-26  5:25 [PATCH v3 1/3] dt-bindings: i2c: nvidia,tegra20-i2c: Specify the required properties Akhil R
2025-05-26  5:25 ` [PATCH v3 2/3] i2c: tegra: make reset an optional property Akhil R
2025-05-26  5:25 ` Akhil R [this message]
2025-05-26  5:40 ` [PATCH v3 1/3] dt-bindings: i2c: nvidia,tegra20-i2c: Specify the required properties Krzysztof Kozlowski
2025-05-26  5:48   ` Krzysztof Kozlowski
2025-05-26  9:03     ` Akhil R
     [not found]   ` <PH7PR12MB8178836F70C0A9F90121676EC062A@PH7PR12MB8178.namprd12.prod.outlook.com>
2025-06-02 11:18     ` Krzysztof Kozlowski

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20250526052553.42766-3-akhilrajeev@nvidia.com \
    --to=akhilrajeev@nvidia.com \
    --cc=andi.shyti@kernel.org \
    --cc=conor+dt@kernel.org \
    --cc=devicetree@vger.kernel.org \
    --cc=digetx@gmail.com \
    --cc=jonathanh@nvidia.com \
    --cc=krzk+dt@kernel.org \
    --cc=ldewangan@nvidia.com \
    --cc=linux-i2c@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-tegra@vger.kernel.org \
    --cc=p.zabel@pengutronix.de \
    --cc=robh@kernel.org \
    --cc=robin.murphy@arm.com \
    --cc=thierry.reding@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox