On 22 March 2014 13:04, Seungwon Jeon <[email protected]> wrote:
> On Fri, March 21, 2014, Ulf Hansson wrote:
>> On 14 March 2014 13:16, Seungwon Jeon <[email protected]> wrote:
>> > Current implementation for bus speed mode selection is too
>> > complicated. This patch is to simplify the codes and remove
>> > some duplicate parts.
>>
>> Really appreciate you taking on this task!
>>
>> >
>> > The following changes are including:
>> > * Adds functions for each mode selection(HS, HS-DDR, HS200 and etc)
>> > * Rearranged the mode selection sequence with supported device type
>> > * Adds maximum speed for HS200 mode(hs200_max_dtr)
>> > * Adds field definition for HS_TIMING of EXT_CSD
>> >
>> > Signed-off-by: Seungwon Jeon <[email protected]>
>> > Tested-by: Jaehoon Chung <[email protected]>
>> > Acked-by: Jaehoon Chung <[email protected]>
>> > ---
>> > drivers/mmc/core/debugfs.c | 2 +-
>> > drivers/mmc/core/mmc.c | 431
>> > ++++++++++++++++++++++++--------------------
>> > include/linux/mmc/card.h | 1 +
>> > include/linux/mmc/mmc.h | 4 +
>> > 4 files changed, 238 insertions(+), 200 deletions(-)
>> >
>> > diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
>> > index 509229b..1f730db 100644
>> > --- a/drivers/mmc/core/debugfs.c
>> > +++ b/drivers/mmc/core/debugfs.c
>> > @@ -139,7 +139,7 @@ static int mmc_ios_show(struct seq_file *s, void *data)
>> > str = "mmc DDR52";
>> > break;
>> > case MMC_TIMING_MMC_HS200:
>> > - str = "mmc high-speed SDR200";
>> > + str = "mmc HS200";
>> > break;
>> > default:
>> > str = "invalid";
>> > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>> > index 480c100..6dd68e6 100644
>> > --- a/drivers/mmc/core/mmc.c
>> > +++ b/drivers/mmc/core/mmc.c
>> > @@ -242,7 +242,7 @@ static void mmc_select_card_type(struct mmc_card *card)
>> > struct mmc_host *host = card->host;
>> > u8 card_type = card->ext_csd.raw_card_type &
>> > EXT_CSD_CARD_TYPE_MASK;
>> > u32 caps = host->caps, caps2 = host->caps2;
>> > - unsigned int hs_max_dtr = 0;
>> > + unsigned int hs_max_dtr = 0, hs200_max_dtr = 0;
>> > unsigned int avail_type = 0;
>> >
>> > if (caps & MMC_CAP_MMC_HIGHSPEED &&
>> > @@ -271,17 +271,18 @@ static void mmc_select_card_type(struct mmc_card
>> > *card)
>> >
>> > if (caps2 & MMC_CAP2_HS200_1_8V_SDR &&
>> > card_type & EXT_CSD_CARD_TYPE_HS200_1_8V) {
>> > - hs_max_dtr = MMC_HS200_MAX_DTR;
>> > + hs200_max_dtr = MMC_HS200_MAX_DTR;
>> > avail_type |= EXT_CSD_CARD_TYPE_HS200_1_8V;
>> > }
>> >
>> > if (caps2 & MMC_CAP2_HS200_1_2V_SDR &&
>> > card_type & EXT_CSD_CARD_TYPE_HS200_1_2V) {
>> > - hs_max_dtr = MMC_HS200_MAX_DTR;
>> > + hs200_max_dtr = MMC_HS200_MAX_DTR;
>> > avail_type |= EXT_CSD_CARD_TYPE_HS200_1_2V;
>> > }
>> >
>> > card->ext_csd.hs_max_dtr = hs_max_dtr;
>> > + card->ext_csd.hs200_max_dtr = hs200_max_dtr;
>> > card->mmc_avail_type = avail_type;
>> > }
>> >
>> > @@ -833,37 +834,46 @@ static int mmc_select_powerclass(struct mmc_card
>> > *card)
>> > }
>> >
>> > /*
>> > - * Selects the desired buswidth and switch to the HS200 mode
>> > - * if bus width set without error
>> > + * Set the bus speed for the selected speed mode.
>> > */
>> > -static int mmc_select_hs200(struct mmc_card *card)
>> > +static void mmc_set_bus_speed(struct mmc_card *card)
>> > +{
>> > + unsigned int max_dtr = (unsigned int)-1;
>>
>> I guess this is to silence compile warnings? Why not just:
>> unsigned int max_dtr = 0;
> Basically, I made an effort to keep the previous codes if it's not a problem.
> If you found something wrong, please let me know.
Got it, let's keep it as is then!
>
>>
>> > +
>> > + if (mmc_card_hs200(card) && max_dtr > card->ext_csd.hs200_max_dtr)
>> > + max_dtr = card->ext_csd.hs200_max_dtr;
>> > + else if (mmc_card_hs(card) && max_dtr > card->ext_csd.hs_max_dtr)
>> > + max_dtr = card->ext_csd.hs_max_dtr;
>> > + else if (max_dtr > card->csd.max_dtr)
>> > + max_dtr = card->csd.max_dtr;
>> > +
>> > + mmc_set_clock(card->host, max_dtr);
>> > +}
>> > +
>> > +/*
>> > + * Select the bus width amoung 4-bit and 8-bit(SDR).
>> > + * If the bus width is changed successfully, return the slected width
>> > value.
>> > + * Zero is returned instead of error value if the wide width is not
>> > supported.
>> > + */
>> > +static int mmc_select_bus_width(struct mmc_card *card)
>> > {
>> > - int idx, err = -EINVAL;
>> > - struct mmc_host *host;
>> > static unsigned ext_csd_bits[] = {
>> > - EXT_CSD_BUS_WIDTH_4,
>> > EXT_CSD_BUS_WIDTH_8,
>> > + EXT_CSD_BUS_WIDTH_4,
>> > };
>> > static unsigned bus_widths[] = {
>> > - MMC_BUS_WIDTH_4,
>> > MMC_BUS_WIDTH_8,
>> > + MMC_BUS_WIDTH_4,
>> > };
>>
>> Do we really need to keep these arrays? The only contain only two values.
>>
>> Can't we just try with 8-bit, if supported, and if it fails try with
>> 4-bit. Would that further simplify the code?
> Yes, current implementation does that.
> First, it tries with 8-bit if supported, and if failed, it will be tried
> with 4-bit.
> And I think using array can make simple retry coding if considering failure
> case.
> I intended to keep original way.
I understand you want to make as small changes as possible, that's
good. So let's keep this as is then.
If we want to change this, we can do that in a follow up patch instead.
>
>>
>> Overall looks good to me, besides the minor comments above.
>>
>> Since this kind of touches quite old code, I would appreciate if it
>> could go though some more testing in linux next, thus it's material
>> for early queueing to 3.16.
>>
>> But before we go on, I would like to know if you managed to test all
>> the different variants of buswidth/speedmode and the bus width test?
>> If there is any specific test would like to get help to run, just tell
>> me.
>>
>> Nice work!
> It would be nice if it's picked for 3.15.
> As I mentioned above, I basically kept the original flow and way.
I leave the decision to Chris. Still I think some more testing in
linux-next would be nice.
Acked-by: Ulf Hansson <[email protected]>
>
> This change applies only to eMMC type and participates only in card
> initialization's process.
> I tested on the following various mode and detection is performed
> successfully.
>
> - HS400 w/ 8-bit
> - HS400 w/ 4-bit : HS200 mode is selected(Because HS400 is possible
> with 8-bit)
> - HS200 w/ 4-bit or 8-bit
> - DDR52 w/ 4-bit or 8-bit
> - High speed w/ 1-bit, 4-bit or 8-bit
> - Backwards w/ 1-bit, 4-bit or 8-bit
>
> I really appreciate your deep reviews.
>
> Thanks,
> Seungwon Jeon
>
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