Re: [PATCH 0/2] mmc: mmci: add quirk property to add stm32 transfer mode

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hi Russell & Ulf

On 2/21/19 11:30 AM, Russell King - ARM Linux admin wrote:
On Thu, Feb 21, 2019 at 10:27:39AM +0000, Russell King - ARM Linux admin wrote:
On Thu, Feb 21, 2019 at 11:10:49AM +0100, Ludovic Barre wrote:
From: Ludovic Barre <ludovic.barre@xxxxxx>

This patch series introduces a bitmap of hardware quirks that require
some special action. This should reduce the number of boolean
into variant structure.
And adds quirk bit to define sdmmc specific transfer modes.

Please find some other way to deal with these differences.  As far as
I'm concerned, introducing a quirk bitmask such as what was done in
sdhci is a complete disaster and leads to long-term maintanability
problems.

We already have a way to deal with variants in mmci.

... to finish what I was saying ...

and I think that:

         if (variant->blksz_datactrl16)
                 datactrl = variant->datactrl_dpsm_enable | (data->blksz << 16);
         else if (variant->blksz_datactrl4)
                 datactrl = variant->datactrl_dpsm_enable | (data->blksz << 4);
         else
                 datactrl = variant->datactrl_dpsm_enable | blksz_bits << 4;

ought to become a variant function call which returns the appropriate
datactrl value.  This would shrink the amount of variant testing in this
path, and also means that going forward we aren't facing an endlessly
increasing number of tests here.

For blksz_datactrl case:
We could create an inline function for datactrl16 and blksz_datactrl4
which returns the appropriate datactrl value (specific for ux500v2 and qcom). This function could be register in mmci_host_ops structure.

in mmci_start_data function we could call a common function which call a
hook if defined.

int mmci_dblksz(struct mmci_host *host)
{
	if (host->ops && host->ops->dblksz)
		return host->ops->dblk(host);

	/* default data block size definition */
	blksz_bits = ffs(data->blksz) - 1;
	return blksz_bits << 4;
}

what do you think about it?
After, I'm afraid to multiply callback function in mmci_host_ops.

For stm32 transfer mode:
ditto, a callback function or I keep a boolean?

BR
Ludo




Ludovic Barre (2):
   mmc: mmci: introduce a quirks property into variant struct
   mmc: mmci: add quirk property to add stm32 transfer mode

  drivers/mmc/host/mmci.c | 11 +++++++++++
  drivers/mmc/host/mmci.h |  9 +++++++++
  2 files changed, 20 insertions(+)

--
2.7.4


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