* [PATCH] Documentation: document dma device use for mcb
@ 2020-12-18 15:35 Johannes Thumshirn
2021-01-11 10:19 ` Johannes Thumshirn
0 siblings, 1 reply; 4+ messages in thread
From: Johannes Thumshirn @ 2020-12-18 15:35 UTC (permalink / raw)
To: Jonathan Corbet; +Cc: linux-doc, linux-kernel, Johannes Thumshirn, Hannes Duerr
Hannes reported a problem with setting up dma transfers on a mcb device.
The problem boiled down to the use of a wrong 'device' for the dma
functions.
Document how to setup dma transfers for a IP core on a mcb carrier.
Reported-by: Hannes Duerr <Hannes.Duerr@duagon.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
Documentation/driver-api/men-chameleon-bus.rst | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/Documentation/driver-api/men-chameleon-bus.rst b/Documentation/driver-api/men-chameleon-bus.rst
index 1b1f048aa748..6f0b9ee47595 100644
--- a/Documentation/driver-api/men-chameleon-bus.rst
+++ b/Documentation/driver-api/men-chameleon-bus.rst
@@ -18,6 +18,7 @@ MEN Chameleon Bus
4.1 The driver structure
4.2 Probing and attaching
4.3 Initializing the driver
+ 4.4 Using DMA
Introduction
@@ -173,3 +174,14 @@ module at the MCB core::
The module_mcb_driver() macro can be used to reduce the above code::
module_mcb_driver(foo_driver);
+
+Using DMA
+---------
+
+To make use of the kernel's DMA-API's function, you will need to use the
+carrier device's 'struct device'. Fortunately 'struct mcb_device' embeds a
+pointer (->dma_dev) to the carrier's device for DMA purposes::
+
+ ret = dma_set_mask_and_coherent(&mdev->dma_dev, DMA_BIT_MASK(dma_bits));
+ if (rc)
+ /* Handle errors */
--
2.26.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] Documentation: document dma device use for mcb
2020-12-18 15:35 [PATCH] Documentation: document dma device use for mcb Johannes Thumshirn
@ 2021-01-11 10:19 ` Johannes Thumshirn
2021-01-11 20:26 ` Jonathan Corbet
0 siblings, 1 reply; 4+ messages in thread
From: Johannes Thumshirn @ 2021-01-11 10:19 UTC (permalink / raw)
To: Jonathan Corbet; +Cc: linux-doc, linux-kernel, Hannes Duerr
On 18/12/2020 16:35, Johannes Thumshirn wrote:
> Hannes reported a problem with setting up dma transfers on a mcb device.
> The problem boiled down to the use of a wrong 'device' for the dma
> functions.
>
> Document how to setup dma transfers for a IP core on a mcb carrier.
Ping?
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Documentation: document dma device use for mcb
2021-01-11 10:19 ` Johannes Thumshirn
@ 2021-01-11 20:26 ` Jonathan Corbet
2021-01-12 10:25 ` Johannes Thumshirn
0 siblings, 1 reply; 4+ messages in thread
From: Jonathan Corbet @ 2021-01-11 20:26 UTC (permalink / raw)
To: Johannes Thumshirn; +Cc: linux-doc, linux-kernel, Hannes Duerr
On Mon, 11 Jan 2021 10:19:55 +0000
Johannes Thumshirn <Johannes.Thumshirn@wdc.com> wrote:
> On 18/12/2020 16:35, Johannes Thumshirn wrote:
> > Hannes reported a problem with setting up dma transfers on a mcb device.
> > The problem boiled down to the use of a wrong 'device' for the dma
> > functions.
> >
> > Document how to setup dma transfers for a IP core on a mcb carrier.
>
> Ping?
Sorry, I've been distracted by holidays, merge window, network issues, and
generally watching the news in horror. The patch is applied now, thanks.
jon
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Documentation: document dma device use for mcb
2021-01-11 20:26 ` Jonathan Corbet
@ 2021-01-12 10:25 ` Johannes Thumshirn
0 siblings, 0 replies; 4+ messages in thread
From: Johannes Thumshirn @ 2021-01-12 10:25 UTC (permalink / raw)
To: Jonathan Corbet; +Cc: linux-doc, linux-kernel, Hannes Duerr
On 11/01/2021 21:27, Jonathan Corbet wrote:
> Sorry, I've been distracted by holidays, merge window, network issues, and
> generally watching the news in horror. The patch is applied now, thanks.
Thanks Jon
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-01-12 10:27 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-12-18 15:35 [PATCH] Documentation: document dma device use for mcb Johannes Thumshirn
2021-01-11 10:19 ` Johannes Thumshirn
2021-01-11 20:26 ` Jonathan Corbet
2021-01-12 10:25 ` Johannes Thumshirn
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