Re: mmc: tmio: why enable/disable SDIO irq on every transaction with IOMOD?

[Wolfram Sang <wsa-dev@sang-engineering.com>]

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Hi,

thanks for the report and thanks to Ulf for forwarding. Adding
renesas-soc list, too.

> > So my question is that "What is the reason behind to disable IRQ with
> > SDIO_MODE?  Is there any situation which masking with SDIO_INFO1_MASK
> > is not enough?

This code predates the time since I took over maintainership of the
driver, so I had to dig in git history.

The code was introduced with 845ecd20239c28 ("mmc: tmio_mmc: implement
SDIO IRQ support") which was in 2010. I don't have that old datasheets
to check if the SCLKDIVEN restriction was already present in the SDHI
cores which were available back then.

My assumption is that it was not, or it was overlooked. So, it might be
just for completeness that not only the individual IRQs have been
disabled but also the big master switch (IOMOD) was turned off.

My further assumption is that it is very likely good enough to disable
the individual IRQs. If we can't guarantee the conditions to set IOMOD,
it seems okay to me to just leave it.

Do you have a patch which works for you?

Regards,

   Wolfram


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