All of lore.kernel.org
 help / color / mirror / Atom feed
From: Chris Ball <cjb@laptop.org>
To: Philip Rakity <prakity@marvell.com>
Cc: "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
	Albert Herranz <albert_herranz@yahoo.es>
Subject: Re: [BUG] CMD52 sent as first command not CMD0
Date: Sun, 6 Feb 2011 00:38:45 +0000	[thread overview]
Message-ID: <20110206003845.GA15019@void.printf.net> (raw)
In-Reply-To: <C85F98EE-B8C5-4037-A0FF-203265A7575C@marvell.com>

Hi Philip,

On Fri, Feb 04, 2011 at 02:53:59PM -0800, Philip Rakity wrote:
> using mmc-next -- NO changes -- last checkin was from linux Jan 26
[..]
> [    2.034998] mmc0: starting CMD52 arg 00000c00 flags 00000195
> [    2.052704] Waiting 15sec before mounting root device...
> [    2.068948] sdhci [sdhci_irq()]: *** mmc0 got interrupt: 0x00018000
> [    2.087707] mmc0: req done (CMD52): -110: 00000000 00000000 00000000 00000000
> [    2.109069] mmc0: starting CMD52 arg 80000c08 flags 00000195
> [    2.126291] sdhci [sdhci_irq()]: *** mmc0 got interrupt: 0x00018000
> [    2.145002] mmc0: req done (CMD52): -110: 00000000 00000000 00000000 00000000
> [    2.166321] mmc0: clock 400000Hz busmode 1 powermode 2 cs 1 Vdd 21 width 0 timing 0
> [    2.190178] mmc0: starting CMD0 arg 00000000 flags 000000c0
> [    2.206971] sdhci [sdhci_irq()]: *** mmc0 got interrupt: 0x00000001
> [    2.225689] mmc0: req done (CMD0): 0: 00000000 00000000 00000000 00000000

This looks to be intentional, and dates back to:

commit 516a82422209e078345d0ca54b16793d7bfd4782
Author: Albert Herranz <albert_herranz@yahoo.es>
Date:   Wed Mar 10 15:20:37 2010 -0800

    sdio: recognize io card without powercycle
    
    SDIO Simplified Specification V2.00 states that it is strongly recommended
    that the host executes either a power reset or issues a CMD52 (I/O Reset)
    to re-initialize an I/O only card or the I/O portion of a combo card.
    Additionally, the CMD52 must be issued first because it cannot be issued
    after a CMD0.
    
    With this patch the Nintendo Wii SDIO-based WLAN card is detected after a
    system reset, without requiring a complete system powercycle.

Are you seeing any negative effects from running the CMD52 before CMD0?

Thanks,

-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child

  parent reply	other threads:[~2011-02-06  0:38 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-04 22:53 [BUG] CMD52 sent as first command not CMD0 Philip Rakity
2011-02-04 23:19 ` Philip Rakity
2011-02-06  0:38 ` Chris Ball [this message]
2011-02-06  0:52   ` Philip Rakity
2011-02-06  1:11     ` Philip Rakity
2011-02-06  1:15     ` Chris Ball
2011-02-06  1:35       ` Philip Rakity
2011-02-06  1:50         ` Chris Ball
2011-02-06 16:02           ` David Vrabel
2011-02-06 11:13         ` Albert Herranz
2011-02-06 20:50           ` Philip Rakity
2011-02-07  0:55             ` Nicolas Pitre
2011-02-06 16:09     ` Tardy, Pierre

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20110206003845.GA15019@void.printf.net \
    --to=cjb@laptop.org \
    --cc=albert_herranz@yahoo.es \
    --cc=linux-mmc@vger.kernel.org \
    --cc=prakity@marvell.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.