> -----Original Message----- > From: Adrian Hunter [mailto:adrian.hunter@xxxxxxxxx] > Sent: Tuesday, July 27, 2010 1:22 PM > To: Ghorai, Sukumar > Cc: linux-mmc@xxxxxxxxxxxxxxx; Andrew Morton > Subject: Re: [PATCH] mmc: add device class attribute for ext_csd > > Ghorai, Sukumar wrote: > > > >> -----Original Message----- > >> From: Adrian Hunter [mailto:adrian.hunter@xxxxxxxxx] > >> Sent: Monday, July 26, 2010 6:13 PM > >> To: Ghorai, Sukumar > >> Cc: linux-mmc@xxxxxxxxxxxxxxx; Andrew Morton > >> Subject: Re: [PATCH] mmc: add device class attribute for ext_csd > >> > >> Ghorai, Sukumar wrote: > >>> All, > >>> EXT_CSD is 512byte information (read using CMD8) for the MMC (eMMC) > >> device. > >>> And for the latest and upcoming specification, ext_csd are much > relevant > >> then past. > >>> So please let me know your idea to add and get the same ext_csd as MMC > >> device attribute. This is the same way currently available for csd, cid, > >> src, etc. > >>> (# cat /sys/class/mmc_host/mmc1/mmc1\:0001/ext_csd) > >> Some of the values in Extended CSD can change so storing > >> it could cause incorrect values to be reported. > > [Ghorai] I was thinking to get the original value as reference, such > that we know that host is capable for maximum negotiation, like 8-bit, DDR > mode, voltage, etc. > > 1. Is there any other way to get the original value supported by card? > > 2. If yes, is it worth full to do? > > If it is for debugging, would a debug prints do instead e.g. > > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c > index 89f7a25..cba87b0 100644 > --- a/drivers/mmc/core/mmc.c > +++ b/drivers/mmc/core/mmc.c > @@ -249,6 +249,9 @@ static int mmc_read_ext_csd(struct mmc_card *card) > 1 << ext_csd[EXT_CSD_S_A_TIMEOUT]; > } > > + pr_debug("%s: initial ext_csd bus width code %02x", > + mmc_hostname(host), ext_csd[EXT_CSD_BUS_WIDTH]); > + [Ghorai] yes, we need this kind messages in some format. So let me add some more important debug print message(s) from ext_csd and submit as a patch. > out: > kfree(ext_csd); > > > > > > >> Note that Extended CSD is available via debugfs > >> e.g. for device mmc0:0001 with debugfs mounted on /sys/kernel/debug > >> > >> cat /sys/kernel/debug/mmc0/mmc0\:0001/ext_csd > > [Ghorai] Thanks. I got it. > > > > <<snip>> > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
