Hi, On Fri, Jan 13, 2012 at 02:25:11AM +0000, Huang Changming-R66093 wrote: > Hi, Chris, > Could you have any comment about this patch? > Can it go into 3.3 or 3.4? > > Thanks > Jerry Huang > > -----Original Message----- > > From: Huang Changming-R66093 > > Sent: Tuesday, December 27, 2011 4:01 PM > > To: [email protected] > > Cc: Huang Changming-R66093; Chris Ball > > Subject: [PATCH 2/4 v4] MMC/SD: Add callback function to detect card > > > > From: Jerry Huang <[email protected]> > > > > In order to check whether the card has been removed, the function > > mmc_send_status() will send command CMD13 to card and ask the card > > to send its status register to sdhc driver, which will generate > > many interrupts repeatedly and make the system performance bad.
For sd hosts, this should only happen for hosts which have SDHCI_QUIRK_BROKEN_CARD_DETECTION set. > > > > Therefore, add callback function get_cd() to check whether > > the card has been removed when the driver has this callback function. I don't quite get the meaning of cd, what does get_cd suppose to mean? > > > > If the card is present, 1 will return, if the card is absent, 0 will > > return. > > If the controller will not support this feature, -ENOSYS will return. What about get_present, return 0 for present, and return error code otherwise like the alive function does. > > > > Signed-off-by: Jerry Huang <[email protected]> > > CC: Chris Ball <[email protected]> > > --- > > changes for v2: > > - when controller don't support get_cd, return -ENOSYS > > - add the CC > > changes for v3: > > - enalbe the controller clock in platform, instead of core > > changes for v4: > > - move the detect code to core.c according to the new structure > > > > drivers/mmc/core/core.c | 10 ++++++++-- > > 1 files changed, 8 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c > > index 6db6621..d570c72 100644 > > --- a/drivers/mmc/core/core.c > > +++ b/drivers/mmc/core/core.c > > @@ -2060,7 +2060,7 @@ static int mmc_rescan_try_freq(struct mmc_host > > *host, unsigned freq) > > snip > > int _mmc_detect_card_removed(struct mmc_host *host) > > { > > - int ret; > > + int ret = -ENOSYS; > > > > if ((host->caps & MMC_CAP_NONREMOVABLE) || !host->bus_ops->alive) > > return 0; > > @@ -2068,7 +2068,13 @@ int _mmc_detect_card_removed(struct mmc_host *host) > > if (!host->card || mmc_card_removed(host->card)) > > return 1; > > > > - ret = host->bus_ops->alive(host); > > + if (host->ops->get_cd) { > > + ret = host->ops->get_cd(host); > > + if (ret >= 0) > > + ret = !ret; > > + } > > + if (ret < 0) > > + ret = host->bus_ops->alive(host); > > if (ret) { > > mmc_card_set_removed(host->card); > > pr_debug("%s: card remove detected\n", mmc_hostname(host)); > > -- > > 1.7.5.4 And the code can be changed to something like: if (host->ops->get_present) ret = host->ops->get_present(host); else ret = host->bus_ops->alive(host); if (ret) { mmc_card_set_removed(host->card); pr_debug("%s: card remove detected\n", mmc_hostname(host)); } Does this make sense? -Aaron > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to [email protected] > 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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
