From: Robert Jarzmik <robert.jarzmik@free.fr>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Mack <daniel@zonque.org>,
Haojian Zhuang <haojian.zhuang@gmail.com>,
Vinod Koul <vinod.koul@intel.com>,
Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
Liam Girdwood <lgirdwood@gmail.com>,
Mark Brown <broonie@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
alsa-devel@alsa-project.org
Subject: Re: [PATCH 14/15] ARM: pxa: change SSP devices allocation
Date: Tue, 03 Apr 2018 17:32:58 +0200 [thread overview]
Message-ID: <87lge4485x.fsf@belgarion.home> (raw)
In-Reply-To: <CAK8P3a2hYWO2eweg3zpR7iJoqtH4uxJLAxJAno7L96G7nA2HxQ@mail.gmail.com> (Arnd Bergmann's message of "Tue, 3 Apr 2018 09:06:46 +0200")
Arnd Bergmann <arnd@arndb.de> writes:
chop chop ... removed several mail recipients to leave only the ASoC / PXA
subset ...
> On Mon, Apr 2, 2018 at 4:26 PM, Robert Jarzmik <robert.jarzmik@free.fr> wrote:
>
>>
>> +static struct pxa_ssp_info pxa_ssp_infos[] = {
>> + { .dma_chan_rx_name = "ssp1_rx", .dma_chan_tx_name = "ssp1_tx", },
>> + { .dma_chan_rx_name = "ssp1_rx", .dma_chan_tx_name = "ssp1_tx", },
>> + { .dma_chan_rx_name = "ssp2_rx", .dma_chan_tx_name = "ssp2_tx", },
>> + { .dma_chan_rx_name = "ssp2_rx", .dma_chan_tx_name = "ssp2_tx", },
>> + { .dma_chan_rx_name = "ssp3_rx", .dma_chan_tx_name = "ssp3_tx", },
>> + { .dma_chan_rx_name = "ssp3_rx", .dma_chan_tx_name = "ssp3_tx", },
>> + { .dma_chan_rx_name = "ssp4_rx", .dma_chan_tx_name = "ssp4_tx", },
>> + { .dma_chan_rx_name = "ssp4_rx", .dma_chan_tx_name = "ssp4_tx", },
>> +};
>
> This part looks odd to me, you're adding an extra level of indirection to
> do two stages of lookups in some form of platform data.
That's unfortunately right.
> Why can't you just always use "rx" and "tx" as the names here?
Well I couldn't. I'll explain you why, and maybe you'll find a better solution.
That all is related to how ASoC and SSP interact.
If I remember correctly, here is how it works :
- the DMA channel is requested in sound/arm/pxa2xx-pcm-lib.c:128
return snd_dmaengine_pcm_open(
substream, dma_request_slave_channel(rtd->platform->dev,
The trick is that the device here is _not_ the SSP one, it's if memory serves
me well the pxa-pcm-audio one.
As a consequence, the device cannot be used to differenciate which SSP
exactly is providing the sound samples stream. This information is
nevertheless required to choose the correct requestor line, which is a 1-to-1
match to the SSP port.
The indirection in the channel name is used to choose the correct requestor
line for a given SSP port providing the samples.
It also must be underlined that this dma request serves both AC97 and SSP as
sample providers.
> (also, I don't see why each line is duplicated, but I'm sure there's
> an easy answer for that).
Ahh that is an unfortunate rebase most probably :)
Cheers.
--
Robert
WARNING: multiple messages have this Message-ID (diff)
From: robert.jarzmik@free.fr (Robert Jarzmik)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 14/15] ARM: pxa: change SSP devices allocation
Date: Tue, 03 Apr 2018 17:32:58 +0200 [thread overview]
Message-ID: <87lge4485x.fsf@belgarion.home> (raw)
In-Reply-To: <CAK8P3a2hYWO2eweg3zpR7iJoqtH4uxJLAxJAno7L96G7nA2HxQ@mail.gmail.com> (Arnd Bergmann's message of "Tue, 3 Apr 2018 09:06:46 +0200")
Arnd Bergmann <arnd@arndb.de> writes:
chop chop ... removed several mail recipients to leave only the ASoC / PXA
subset ...
> On Mon, Apr 2, 2018 at 4:26 PM, Robert Jarzmik <robert.jarzmik@free.fr> wrote:
>
>>
>> +static struct pxa_ssp_info pxa_ssp_infos[] = {
>> + { .dma_chan_rx_name = "ssp1_rx", .dma_chan_tx_name = "ssp1_tx", },
>> + { .dma_chan_rx_name = "ssp1_rx", .dma_chan_tx_name = "ssp1_tx", },
>> + { .dma_chan_rx_name = "ssp2_rx", .dma_chan_tx_name = "ssp2_tx", },
>> + { .dma_chan_rx_name = "ssp2_rx", .dma_chan_tx_name = "ssp2_tx", },
>> + { .dma_chan_rx_name = "ssp3_rx", .dma_chan_tx_name = "ssp3_tx", },
>> + { .dma_chan_rx_name = "ssp3_rx", .dma_chan_tx_name = "ssp3_tx", },
>> + { .dma_chan_rx_name = "ssp4_rx", .dma_chan_tx_name = "ssp4_tx", },
>> + { .dma_chan_rx_name = "ssp4_rx", .dma_chan_tx_name = "ssp4_tx", },
>> +};
>
> This part looks odd to me, you're adding an extra level of indirection to
> do two stages of lookups in some form of platform data.
That's unfortunately right.
> Why can't you just always use "rx" and "tx" as the names here?
Well I couldn't. I'll explain you why, and maybe you'll find a better solution.
That all is related to how ASoC and SSP interact.
If I remember correctly, here is how it works :
- the DMA channel is requested in sound/arm/pxa2xx-pcm-lib.c:128
return snd_dmaengine_pcm_open(
substream, dma_request_slave_channel(rtd->platform->dev,
The trick is that the device here is _not_ the SSP one, it's if memory serves
me well the pxa-pcm-audio one.
As a consequence, the device cannot be used to differenciate which SSP
exactly is providing the sound samples stream. This information is
nevertheless required to choose the correct requestor line, which is a 1-to-1
match to the SSP port.
The indirection in the channel name is used to choose the correct requestor
line for a given SSP port providing the samples.
It also must be underlined that this dma request serves both AC97 and SSP as
sample providers.
> (also, I don't see why each line is duplicated, but I'm sure there's
> an easy answer for that).
Ahh that is an unfortunate rebase most probably :)
Cheers.
--
Robert
next prev parent reply other threads:[~2018-04-03 15:33 UTC|newest]
Thread overview: 218+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-02 14:26 [PATCH 00/15] ARM: pxa: switch to DMA slave maps Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` [01/15] dmaengine: pxa: use a dma slave map Robert Jarzmik
2018-04-02 14:26 ` [PATCH 01/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-21 19:23 ` Robert Jarzmik
2018-04-02 14:26 ` [04/15] media: pxa_camera: remove the dmaengine compat need Robert Jarzmik
2018-04-02 14:26 ` [PATCH 04/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-21 19:27 ` Robert Jarzmik
2018-04-21 19:27 ` Robert Jarzmik
2018-04-22 11:06 ` Hans Verkuil
2018-04-22 11:06 ` Hans Verkuil
2018-04-02 14:26 ` [05/15] mtd: nand: pxa3xx: " Robert Jarzmik
2018-04-02 14:26 ` [PATCH 05/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-03 7:33 ` Miquel Raynal
2018-04-03 15:19 ` Robert Jarzmik
2018-04-02 14:26 ` [09/15] net: irda: pxaficp_ir: " Robert Jarzmik
2018-04-02 14:26 ` [PATCH 09/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-21 19:30 ` Robert Jarzmik
2018-04-21 19:30 ` Robert Jarzmik
2018-04-02 14:26 ` [10/15] ata: pata_pxa: " Robert Jarzmik
2018-04-02 14:26 ` [PATCH 10/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-21 19:32 ` Robert Jarzmik
2018-04-21 19:32 ` Robert Jarzmik
2018-04-24 11:04 ` Bartlomiej Zolnierkiewicz
2018-04-24 11:04 ` Bartlomiej Zolnierkiewicz
2018-04-02 14:26 ` [14/15] ARM: pxa: change SSP devices allocation Robert Jarzmik
2018-04-02 14:26 ` [PATCH 14/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-03 7:06 ` [14/15] " Arnd Bergmann
2018-04-03 7:06 ` [PATCH 14/15] " Arnd Bergmann
2018-04-03 7:06 ` Arnd Bergmann
2018-04-03 7:06 ` Arnd Bergmann
2018-04-03 7:06 ` Arnd Bergmann
2018-04-03 7:06 ` Arnd Bergmann
2018-04-03 15:32 ` Robert Jarzmik [this message]
2018-04-03 15:32 ` Robert Jarzmik
2018-04-03 15:53 ` Arnd Bergmann
2018-04-03 15:53 ` Arnd Bergmann
2018-04-05 6:51 ` Robert Jarzmik
2018-04-05 6:51 ` Robert Jarzmik
2018-04-05 7:29 ` Arnd Bergmann
2018-04-05 7:29 ` Arnd Bergmann
2018-04-08 12:16 ` Robert Jarzmik
2018-04-08 12:16 ` Robert Jarzmik
2018-04-08 12:16 ` Robert Jarzmik
2018-04-03 7:15 ` [PATCH 00/15] ARM: pxa: switch to DMA slave maps Arnd Bergmann
2018-04-03 7:15 ` Arnd Bergmann
2018-04-03 7:15 ` Arnd Bergmann
2018-04-03 7:15 ` Arnd Bergmann
2018-04-03 7:15 ` Arnd Bergmann
2018-04-03 15:08 ` Ulf Hansson
2018-04-03 15:08 ` Ulf Hansson
2018-04-03 15:08 ` Ulf Hansson
2018-04-03 15:08 ` Ulf Hansson
2018-04-04 19:49 ` Robert Jarzmik
2018-04-04 19:49 ` Robert Jarzmik
2018-04-04 19:49 ` Robert Jarzmik
2018-04-04 19:49 ` Robert Jarzmik
2018-04-04 19:56 ` Boris Brezillon
2018-04-04 19:56 ` Boris Brezillon
2018-04-04 19:56 ` Boris Brezillon
2018-04-04 19:56 ` Boris Brezillon
2018-04-04 19:56 ` Boris Brezillon
2018-04-05 6:29 ` Ulf Hansson
2018-04-05 6:29 ` Ulf Hansson
2018-04-05 6:29 ` Ulf Hansson
2018-04-05 6:29 ` Ulf Hansson
2018-04-05 6:50 ` Arnd Bergmann
2018-04-05 6:50 ` Arnd Bergmann
2018-04-05 6:50 ` Arnd Bergmann
2018-04-05 6:50 ` Arnd Bergmann
2018-04-02 14:26 [02/15] ARM: pxa: add dma slave map Robert Jarzmik
2018-04-02 14:26 ` [PATCH 02/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 [03/15] mmc: pxamci: remove the dmaengine compat need Robert Jarzmik
2018-04-02 14:26 ` [PATCH 03/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 [06/15] net: smc911x: " Robert Jarzmik
2018-04-02 14:26 ` [PATCH 06/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 [07/15] net: smc91x: " Robert Jarzmik
2018-04-02 14:26 ` [PATCH 07/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 [08/15] ASoC: pxa: " Robert Jarzmik
2018-04-02 14:26 ` [PATCH 08/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 [11/15] dmaengine: pxa: document pxad_param Robert Jarzmik
2018-04-02 14:26 ` [PATCH 11/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 [12/15] dmaengine: pxa: make the filter function internal Robert Jarzmik
2018-04-02 14:26 ` [PATCH 12/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 [13/15] ARM: pxa: remove the DMA IO resources Robert Jarzmik
2018-04-02 14:26 ` [PATCH 13/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 [15/15] ARM: pxa: change SSP DMA channels allocation Robert Jarzmik
2018-04-02 14:26 ` [PATCH 15/15] " Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 14:26 ` Robert Jarzmik
2018-04-02 16:25 [12/15] dmaengine: pxa: make the filter function internal kbuild test robot
2018-04-02 16:25 ` [PATCH 12/15] " kbuild test robot
2018-04-02 16:25 ` kbuild test robot
2018-04-02 16:25 ` kbuild test robot
2018-04-02 16:25 ` kbuild test robot
2018-04-02 16:35 [12/15] " kbuild test robot
2018-04-02 16:35 ` [PATCH 12/15] " kbuild test robot
2018-04-02 16:35 ` kbuild test robot
2018-04-02 16:35 ` kbuild test robot
2018-04-02 16:35 ` kbuild test robot
2018-04-02 16:35 ` kbuild test robot
2018-04-02 18:46 [15/15] ARM: pxa: change SSP DMA channels allocation kbuild test robot
2018-04-02 18:46 ` [PATCH 15/15] " kbuild test robot
2018-04-02 18:46 ` kbuild test robot
2018-04-02 18:46 ` kbuild test robot
2018-04-02 18:46 ` kbuild test robot
2018-04-03 6:51 [02/15] ARM: pxa: add dma slave map Arnd Bergmann
2018-04-03 6:51 ` [PATCH 02/15] " Arnd Bergmann
2018-04-03 6:51 ` Arnd Bergmann
2018-04-03 6:51 ` Arnd Bergmann
2018-04-03 6:51 ` Arnd Bergmann
2018-04-03 6:51 ` Arnd Bergmann
2018-04-03 7:13 [12/15] dmaengine: pxa: make the filter function internal Arnd Bergmann
2018-04-03 7:13 ` [PATCH 12/15] " Arnd Bergmann
2018-04-03 7:13 ` Arnd Bergmann
2018-04-03 7:13 ` Arnd Bergmann
2018-04-03 7:13 ` Arnd Bergmann
2018-04-03 7:13 ` Arnd Bergmann
2018-04-03 15:18 [02/15] ARM: pxa: add dma slave map Robert Jarzmik
2018-04-03 15:18 ` [PATCH 02/15] " Robert Jarzmik
2018-04-03 15:18 ` Robert Jarzmik
2018-04-03 15:18 ` Robert Jarzmik
2018-04-03 15:18 ` Robert Jarzmik
2018-04-03 15:39 [02/15] " Arnd Bergmann
2018-04-03 15:39 ` [PATCH 02/15] " Arnd Bergmann
2018-04-03 15:39 ` Arnd Bergmann
2018-04-03 15:39 ` Arnd Bergmann
2018-04-03 15:39 ` Arnd Bergmann
2018-04-03 15:39 ` Arnd Bergmann
2018-04-03 20:19 [02/15] " Robert Jarzmik
2018-04-03 20:19 ` [PATCH 02/15] " Robert Jarzmik
2018-04-03 20:19 ` Robert Jarzmik
2018-04-04 10:18 [02/15] " Arnd Bergmann
2018-04-04 10:18 ` [PATCH 02/15] " Arnd Bergmann
2018-04-04 10:18 ` Arnd Bergmann
2018-04-04 19:21 [02/15] " Robert Jarzmik
2018-04-04 19:21 ` [PATCH 02/15] " Robert Jarzmik
2018-04-04 19:21 ` Robert Jarzmik
2018-04-12 15:26 [08/15] ASoC: pxa: remove the dmaengine compat need Mark Brown
2018-04-12 15:26 ` [PATCH 08/15] " Mark Brown
2018-04-12 15:26 ` Mark Brown
2018-04-12 15:26 ` Mark Brown
2018-04-12 15:26 ` Mark Brown
2018-04-12 15:26 ` Mark Brown
2018-04-12 16:55 [08/15] " Robert Jarzmik
2018-04-12 16:55 ` [PATCH 08/15] " Robert Jarzmik
2018-04-12 16:55 ` Robert Jarzmik
2018-04-12 16:55 ` Robert Jarzmik
2018-04-12 16:55 ` Robert Jarzmik
2018-04-12 16:55 ` Robert Jarzmik
2018-04-22 6:13 [01/15] dmaengine: pxa: use a dma slave map Vinod Koul
2018-04-22 6:13 ` [PATCH 01/15] " Vinod Koul
2018-04-22 6:13 ` Vinod Koul
2018-04-22 11:06 [04/15] media: pxa_camera: remove the dmaengine compat need Hans Verkuil
2018-04-22 11:06 ` [PATCH 04/15] " Hans Verkuil
2018-04-22 11:06 ` Hans Verkuil
2018-04-22 11:06 ` Hans Verkuil
2018-04-23 8:37 [09/15] net: irda: pxaficp_ir: " Greg Kroah-Hartman
2018-04-23 8:37 ` [PATCH 09/15] " Greg Kroah-Hartman
2018-04-23 8:37 ` Greg Kroah-Hartman
2018-04-23 8:37 ` Greg Kroah-Hartman
2018-04-23 8:37 ` Greg Kroah-Hartman
2018-05-04 19:29 [04/15] media: pxa_camera: " Mauro Carvalho Chehab
2018-05-04 19:29 ` [PATCH 04/15] " Mauro Carvalho Chehab
2018-05-04 19:29 ` Mauro Carvalho Chehab
2018-05-04 19:29 ` Mauro Carvalho Chehab
2018-05-04 19:29 ` Mauro Carvalho Chehab
2018-05-18 21:31 [05/15] mtd: nand: pxa3xx: " Daniel Mack
2018-05-18 21:31 ` [PATCH 05/15] " Daniel Mack
2018-05-18 21:31 ` Daniel Mack
2018-05-18 21:31 ` Daniel Mack
2018-05-23 21:54 [05/15] " Daniel Mack
2018-05-23 21:54 ` [PATCH 05/15] " Daniel Mack
2018-05-23 21:54 ` Daniel Mack
2018-05-23 21:54 ` Daniel Mack
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