From: Frank Li <Frank.Li@nxp.com>
To: Vinod Koul <vkoul@kernel.org>
Cc: linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org,
imx@lists.linux.dev, joy.zou@nxp.com,
Frank Li <Frank.Li@nxp.com>
Subject: [PATCH RFC 07/12] dmaengine: virt-dma: split vchan_tx_prep() into init and internal helpers
Date: Wed, 28 Jan 2026 13:05:26 -0500 [thread overview]
Message-ID: <20260128-dma_ll_comlib-v1-7-1b1fa2c671f9@nxp.com> (raw)
In-Reply-To: <20260128-dma_ll_comlib-v1-0-1b1fa2c671f9@nxp.com>
Split vchan_tx_prep() into vchan_init_dma_async_tx() and __vchan_tx_prep()
to prepare for supporting the common linked-list DMA library.
struct dma_async_tx_descriptor already contains the dma_chan pointer, so
drivers do not need to duplicate it in their own descriptor structures
derived from vchan_desc.
Previously, dma_chan was NULL during descriptor preparation because
vchan_init_dma_async_tx() was called too late. Initializing the
dma_async_tx_descriptor earlier allows drivers to directly access
dma_chan during the prepare phase.
No functional change.
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
drivers/dma/virt-dma.h | 38 ++++++++++++++++++++++++++------------
1 file changed, 26 insertions(+), 12 deletions(-)
diff --git a/drivers/dma/virt-dma.h b/drivers/dma/virt-dma.h
index a15f9e318ca5ec7fd3c4e6fc6864ad3d1dc3eaa5..ad5ce489cf8e52aa02a0129bc5657fadd6070da2 100644
--- a/drivers/dma/virt-dma.h
+++ b/drivers/dma/virt-dma.h
@@ -80,17 +80,22 @@ struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *, dma_cookie_t);
extern dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *);
extern int vchan_tx_desc_free(struct dma_async_tx_descriptor *);
-/**
- * vchan_tx_prep - prepare a descriptor
- * @vc: virtual channel allocating this descriptor
- * @vd: virtual descriptor to prepare
- * @tx_flags: flags argument passed in to prepare function
- */
-static inline struct dma_async_tx_descriptor *vchan_tx_prep(struct virt_dma_chan *vc,
- struct virt_dma_desc *vd, unsigned long tx_flags)
+static inline struct dma_async_tx_descriptor *
+__vchan_tx_prep(struct virt_dma_chan *vc, struct virt_dma_desc *vd)
{
unsigned long flags;
+ spin_lock_irqsave(&vc->lock, flags);
+ list_add_tail(&vd->node, &vc->desc_allocated);
+ spin_unlock_irqrestore(&vc->lock, flags);
+
+ return &vd->tx;
+}
+
+static inline void
+vchan_init_dma_async_tx(struct virt_dma_chan *vc, struct virt_dma_desc *vd,
+ unsigned long tx_flags)
+{
dma_async_tx_descriptor_init(&vd->tx, &vc->chan);
vd->tx.flags = tx_flags;
vd->tx.tx_submit = vchan_tx_submit;
@@ -98,12 +103,21 @@ static inline struct dma_async_tx_descriptor *vchan_tx_prep(struct virt_dma_chan
vd->tx_result.result = DMA_TRANS_NOERROR;
vd->tx_result.residue = 0;
+}
- spin_lock_irqsave(&vc->lock, flags);
- list_add_tail(&vd->node, &vc->desc_allocated);
- spin_unlock_irqrestore(&vc->lock, flags);
+/**
+ * vchan_tx_prep - prepare a descriptor
+ * @vc: virtual channel allocating this descriptor
+ * @vd: virtual descriptor to prepare
+ * @tx_flags: flags argument passed in to prepare function
+ */
+static inline struct dma_async_tx_descriptor *
+vchan_tx_prep(struct virt_dma_chan *vc, struct virt_dma_desc *vd,
+ unsigned long tx_flags)
+{
+ vchan_init_dma_async_tx(vc, vd, tx_flags);
- return &vd->tx;
+ return __vchan_tx_prep(vc, vd);
}
/**
--
2.34.1
next prev parent reply other threads:[~2026-01-28 18:06 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-28 18:05 [PATCH RFC 00/12] dmaengine: introduce common linked-list DMA controller framework Frank Li
2026-01-28 18:05 ` [PATCH RFC 01/12] dmaengine: Extend virt_chan for link list based DMA engines Frank Li
2026-01-28 18:05 ` [PATCH RFC 02/12] dmaengine: Add common dma_ll_desc and dma_linklist_item for link-list controllers Frank Li
2026-01-28 18:05 ` [PATCH RFC 03/12] dmaengine: fsl-edma: Remove redundant echan from struct fsl_edma_desc Frank Li
2026-01-28 18:05 ` [PATCH RFC 04/12] dmaengine: fsl-edma: Use common dma_ll_desc in vchan Frank Li
2026-01-28 18:05 ` [PATCH RFC 05/12] dmaengine: Add DMA pool allocation in vchan_dma_ll_init() and API vchan_dma_ll_free() Frank Li
2026-01-28 18:05 ` [PATCH RFC 06/12] dmaengine: Move fsl_edma_(alloc|free)_desc() to common library Frank Li
2026-01-28 18:05 ` Frank Li [this message]
2026-01-28 18:05 ` [PATCH RFC 08/12] dmaengine: Factor out fsl-edma prep_memcpy into common vchan helper Frank Li
2026-01-28 18:05 ` [PATCH RFC 09/12] dmaengine: ll-dma: support multi-descriptor memcpy for large transfers Frank Li
2026-01-28 18:05 ` [PATCH RFC 10/12] dmaengine: move fsl-edma dma_[un]map_resource() to linked list library Frank Li
2026-01-28 18:05 ` [PATCH RFC 11/12] dmaengine: fsl-edma: use local soff/doff variables Frank Li
2026-01-28 18:05 ` [PATCH RFC 12/12] dmaengine: add vchan_dma_ll_prep_slave_{sg,cyclic} API Frank Li
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=20260128-dma_ll_comlib-v1-7-1b1fa2c671f9@nxp.com \
--to=frank.li@nxp.com \
--cc=dmaengine@vger.kernel.org \
--cc=imx@lists.linux.dev \
--cc=joy.zou@nxp.com \
--cc=linux-kernel@vger.kernel.org \
--cc=vkoul@kernel.org \
/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