Hi Felipe,

On Monday 23 May 2016 12:48 PM, Felipe Balbi wrote:

Hi Kishon,

Kishon Vijay Abraham I [off-list ref] writes:

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Hi Felipe,

On Friday 20 May 2016 12:06 AM, Felipe Balbi wrote:

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Hi,

Tony Lindgren [off-list ref] writes:

quoted

* Peter Ujfalusi [off-list ref] [160519 01:10]:

quoted

On 05/18/2016 10:30 PM, Tony Lindgren wrote:

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Ideally the adma support would be a separate loadable module,
similar how the cppi41dma is a child of the OTG controller.

The Master DMA is part of the hsmmc IP block. If the same ADMA module is
present on other IPs it might be beneficial to have a helper library to handle
it (allocating the descriptor pool, wrinting, updating descriptors, etc).

OK. Yeah if it's part of the MMC controller it makes no sense to
separate it. So then the conecrns are using alternate DMA
implementations and keeping PM runtime working :)

BTW, Felipe mentioned that the best thing to do in the long run would
be to set up sdhci-omap.c operating in ADMA mode.

Felipe, care to summarize what you had in mind?

yeah, just write a new sdhci-omap.c to start moving away from
omap-hsmmc.c, just like it was done for 8250-omap.

At the beginning, it could be just the bare minimum to get it working
and slowly move over stuff like pm runtime, dmaengine, PIO. Move more
platforms over to that driver and, eventually, get rid of omap-hsmmc.c
altogether.

That way, development can be focussed on generic layers (SDHCI) to which
OMAP MMC controller is compliant (apart from the VERSION register
quirk).

About an year back, when I tried using SDHCI for OMAP I ran into
issues and was not able to get it working. IIRC SDHCI_PRESENT_STATE
(or OMAP_HSMMC_PSTATE) was not showing the correct state for card
present and is unable to raise an interrupt when a card is inserted. I
didn't debug this further.

I'd say this is a bug in hsmmc. I remember seeing some bits in some
TI-specific register (before SDHCI address space starts) which can be
used to keep parts of SDHCI powered on exactly so normal WP and CD pins
work as expected.

In any case, adding support for GPIO-based card detect to generic SDHCI
shouldn't be too difficult :-)

quoted

It also kept me wondering why gpio interrupt was always used for card
detect instead of using mmci_sdcd line of the controller.

Probably a really, really old bug which nobody ever debugged properly ;-)

ps: you don't need that ADMA2 DT property, btw. There's a bit in another
register which you can check if $this controller was configured with
ADMA2 support or not. IIRC, OMAP5's TRM describes them.

hmm yeah.. Should be the MADMA_EN in MMCHS_HL_HWINFO.

Thanks
Kishon