RE: [PATCH] powerpc/esdhc: enable the card insert/remove interrupt

Hi, Anton,
For the current polling mode, driver will send CMD13 to poll the card status periodically , which will cause too many interrupts.
Once I sent patches to detect the card when using polling mode last year: read the state register, instead of send CMD13. But, these patches were not accepted. Now I attach them for you.

Because these patches are not accepted, I think about the interrupt mode to detect card.
Of course, you are right, the p4080ds and mpc837xmds are still using polling mode, which just fix some boards.
The best way is for all.

Then, I will back to my previous patches, for FSL eSDHC, don't send CMD13, and just read state register to check it.
For all FSL silicones, the state bit is updated when card inserting or removing.

Now I have two ways to resolve this issue, I prefer to the polling mode (unfortunately, they are not accepted).
I will be greatly appreciated if you review these attachment patches again and give your comment.
If you think the attachment patches are OK, I will resend them to mail list.
If you don't, I will continue to work on the interrupt mode for FSL eSDHC.

Thanks. 

-----Original Message-----
From: linux-mmc-owner@vger.kernel.org [mailto:linux-mmc-
owner@vger.kernel.org] On Behalf Of Anton Vorontsov
Sent: Thursday, October 25, 2012 6:31 PM
To: Huang Changming-R66093
Cc: linux-mmc@vger.kernel.org; Chris Ball; Kumar Gala; linuxppc-
dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc/esdhc: enable the card insert/remove
interrupt

On Thu, Oct 25, 2012 at 10:05:44AM +0000, Huang Changming-R66093 wrote:

quoted

Hi, Anton.
Could you have any comment about it?
If not, I will resend this patch with v2.

Technically, the patch looks fine.

But again, as far as I recall, the card detection logic was broken on the
SOC level (it's actually very hard to break it on the board level -- it
would either work or not, but in the eSDHC case it was just unreliable,
again, if I recall everything correctly -- I might be wrong).

Of course you know the hardware much better, so your words weight more,
so you don't need my ack on the patch. :)

Although there's a second issue: for P4080DS and mpc837x boards you still
have the same problem with polling method, right? It is causing
performance drops/freezes every like 100 ms, and that's why you want to
avoid the polling.

So, you've "fixed" some boards, but left others to suffer. Ideally, the
best fix would be to also make the card polling cheap.

Anyways, using (d) clause of the "Reviewer's statement of oversight", I
can easily give this:

	Reviewed-by: Anton Vorontsov [off-list ref]

:)

Thanks!

[...]

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IIRC, the card detection is broken SOC-revision-wise, not board-

wise.

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So the change seems wrong.

Also, take a look at this:

	http://lkml.org/lkml/2010/7/14/127

I started the work but never finished, unfortunately it caused
some regressions for non-FSL hardware...

quoted

 drivers/mmc/host/sdhci-of-esdhc.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-of-esdhc.c

b/drivers/mmc/host/sdhci-of-esdhc.c
index ffc1226..5dc362f 100644

--- a/drivers/mmc/host/sdhci-of-esdhc.c
+++ b/drivers/mmc/host/sdhci-of-esdhc.c

@@ -196,6 +196,11 @@ static void

esdhc_of_detect_limitation(struct

platform_device *pdev,

quoted

 	if (vvn == VENDOR_V_22)
 		pdata->quirks2 |= SDHCI_QUIRK2_HOST_NO_CMD23;

+	/* P4080DS and MPC837XMDS board don't support interrupt mode

*/

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+	if (of_machine_is_compatible("fsl,mpc837xmds") ||
+	    of_machine_is_compatible("fsl,P4080DS"))
+		pdata->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
+
 	iounmap(ioaddr);
 end:
 	return;

@@ -223,7 +228,7 @@ static struct sdhci_pltfm_data

sdhci_esdhc_pdata =

{

quoted

 	 * card detection could be handled via GPIO
 	 * eSDHC cannot support End Attribute in NOP ADMA descriptor
 	 */
-	.quirks = ESDHC_DEFAULT_QUIRKS |

SDHCI_QUIRK_BROKEN_CARD_DETECTION

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+	.quirks = ESDHC_DEFAULT_QUIRKS
 		| SDHCI_QUIRK_NO_CARD_NO_RESET
 		| SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC,
 	.ops = &sdhci_esdhc_ops,
--
1.7.9.5

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