On 25 March 2014 10:23, Seungwon Jeon <tgih.jun@xxxxxxxxxxx> wrote:
> Hi Ulf,
>
> On Tue, March 25, 2014, Ulf Hansson wrote:
>> On 14 March 2014 13:16, Seungwon Jeon <tgih.jun@xxxxxxxxxxx> wrote:
>> > This patch adds HS400 mode support for eMMC5.0 device.
>> > HS400 mode is high speed DDR interface timing from HS200.
>> > Clock frequency is up to 200MHz and only 8-bit bus width is
>> > supported. In addition, tuning process of HS200 is required
>> > to synchronize the command response on the CMD line because
>> > CMD input timing for HS400 mode is the same as HS200 mode.
>> >
>> > Signed-off-by: Seungwon Jeon <tgih.jun@xxxxxxxxxxx>
>> > Reviewed-by: Jackey Shen <jackey.shen@xxxxxxx>
>> > Tested-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
>> > Acked-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
>> > ---
>> > drivers/mmc/core/bus.c | 1 +
>> > drivers/mmc/core/debugfs.c | 3 +
>> > drivers/mmc/core/mmc.c | 115 +++++++++++++++++++++++++++++++++++++++++--
>> > include/linux/mmc/card.h | 1 +
>> > include/linux/mmc/host.h | 15 +++++-
>> > include/linux/mmc/mmc.h | 7 ++-
>> > 6 files changed, 134 insertions(+), 8 deletions(-)
>> >
>> > diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
>> > index f37e9d6..d2dbf02 100644
>> > --- a/drivers/mmc/core/bus.c
>> > +++ b/drivers/mmc/core/bus.c
>> > @@ -349,6 +349,7 @@ int mmc_add_card(struct mmc_card *card)
>> > mmc_hostname(card->host),
>> > mmc_card_uhs(card) ? "ultra high speed " :
>> > (mmc_card_hs(card) ? "high speed " : ""),
>> > + mmc_card_hs400(card) ? "HS400 " :
>> > (mmc_card_hs200(card) ? "HS200 " : ""),
>> > mmc_card_ddr52(card) ? "DDR " : "",
>> > uhs_bus_speed_mode, type, card->rca);
>> > diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
>> > index 1f730db..91eb162 100644
>> > --- a/drivers/mmc/core/debugfs.c
>> > +++ b/drivers/mmc/core/debugfs.c
>> > @@ -141,6 +141,9 @@ static int mmc_ios_show(struct seq_file *s, void *data)
>> > case MMC_TIMING_MMC_HS200:
>> > str = "mmc HS200";
>> > break;
>> > + case MMC_TIMING_MMC_HS400:
>> > + str = "mmc HS400";
>> > + break;
>> > default:
>> > str = "invalid";
>> > break;
>> > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>> > index 6dd68e6..969d595 100644
>> > --- a/drivers/mmc/core/mmc.c
>> > +++ b/drivers/mmc/core/mmc.c
>> > @@ -240,7 +240,7 @@ static int mmc_get_ext_csd(struct mmc_card *card, u8 **new_ext_csd)
>> > 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;
>> > + u8 card_type = card->ext_csd.raw_card_type;
>> > u32 caps = host->caps, caps2 = host->caps2;
>> > unsigned int hs_max_dtr = 0, hs200_max_dtr = 0;
>> > unsigned int avail_type = 0;
>> > @@ -281,6 +281,18 @@ static void mmc_select_card_type(struct mmc_card *card)
>> > avail_type |= EXT_CSD_CARD_TYPE_HS200_1_2V;
>> > }
>> >
>> > + if (caps2 & MMC_CAP2_HS400_1_8V &&
>> > + card_type & EXT_CSD_CARD_TYPE_HS400_1_8V) {
>> > + hs200_max_dtr = MMC_HS200_MAX_DTR;
>> > + avail_type |= EXT_CSD_CARD_TYPE_HS400_1_8V;
>> > + }
>> > +
>> > + if (caps2 & MMC_CAP2_HS400_1_2V &&
>> > + card_type & EXT_CSD_CARD_TYPE_HS400_1_2V) {
>> > + hs200_max_dtr = MMC_HS200_MAX_DTR;
>> > + avail_type |= EXT_CSD_CARD_TYPE_HS400_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;
>> > @@ -499,6 +511,8 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
>> > ext_csd[EXT_CSD_PWR_CL_DDR_52_195];
>> > card->ext_csd.raw_pwr_cl_ddr_52_360 =
>> > ext_csd[EXT_CSD_PWR_CL_DDR_52_360];
>> > + card->ext_csd.raw_pwr_cl_ddr_200_360 =
>> > + ext_csd[EXT_CSD_PWR_CL_DDR_200_360];
>> > }
>> >
>> > if (card->ext_csd.rev >= 5) {
>> > @@ -665,7 +679,10 @@ static int mmc_compare_ext_csds(struct mmc_card *card, unsigned bus_width)
>> > (card->ext_csd.raw_pwr_cl_ddr_52_195 ==
>> > bw_ext_csd[EXT_CSD_PWR_CL_DDR_52_195]) &&
>> > (card->ext_csd.raw_pwr_cl_ddr_52_360 ==
>> > - bw_ext_csd[EXT_CSD_PWR_CL_DDR_52_360]));
>> > + bw_ext_csd[EXT_CSD_PWR_CL_DDR_52_360]) &&
>> > + (card->ext_csd.raw_pwr_cl_ddr_200_360 ==
>> > + bw_ext_csd[EXT_CSD_PWR_CL_DDR_200_360]));
>> > +
>> > if (err)
>> > err = -EINVAL;
>> >
>> > @@ -776,7 +793,9 @@ static int __mmc_select_powerclass(struct mmc_card *card,
>> > ext_csd->raw_pwr_cl_52_360 :
>> > ext_csd->raw_pwr_cl_ddr_52_360;
>> > else if (host->ios.clock <= MMC_HS200_MAX_DTR)
>> > - pwrclass_val = ext_csd->raw_pwr_cl_200_360;
>> > + pwrclass_val = (bus_width == EXT_CSD_DDR_BUS_WIDTH_8) ?
>> > + ext_csd->raw_pwr_cl_ddr_200_360 :
>> > + ext_csd->raw_pwr_cl_200_360;
>> > break;
>> > default:
>> > pr_warning("%s: Voltage range not supported "
>> > @@ -840,7 +859,8 @@ static void mmc_set_bus_speed(struct mmc_card *card)
>> > {
>> > unsigned int max_dtr = (unsigned int)-1;
>> >
>> > - if (mmc_card_hs200(card) && max_dtr > card->ext_csd.hs200_max_dtr)
>> > + if ((mmc_card_hs200(card) || mmc_card_hs400(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;
>> > @@ -939,6 +959,28 @@ static int mmc_select_hs(struct mmc_card *card)
>> > }
>> >
>> > /*
>> > + * Revert to the high-speed mode from above speed
>> > + */
>> > +static int mmc_revert_to_hs(struct mmc_card *card)
>> > +{
>> > + /*
>> > + * CMD13, which is used to confirm the completion of timing
>> > + * change, will be issued at higher speed timing condtion
>> > + * rather than high-speed. If device has completed the change
>> > + * to high-speed mode, it may not be proper timing to issue
>> > + * command. Low speed supplies better timing margin than high
>> > + * speed. Accordingly clock rate & timging should be chagned
>> > + * ahead before actual switch.
>>
>> I have some problem to understand this comment. I guess you are trying
>> to provide the arguments to why it makes sense to perform the revert
>> to lower speed mode!?
>>
>> This makes me wonder if this is not part of the spec? Could you try to clarify?
> But specification says that "HS_TIMING must be set to "0x1" before setting BUS_WIDTH for dual data rate operation".
> I think this sequence is not graceful.
> I also commented why speed mode should be changed to high-speed mode from HS200 mode in the function-called part.
> Because it is not possible to set 8-bit data bus for dual rate on HS200 mode, revert to high-speed from HS200 is needed.
> If the above-commented point makes it confused, it could be removed.
> Please let me know your opinion.
>
>>
>> > + */
>> > + mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
>> > + mmc_set_bus_speed(card);
>> > +
>> > + return mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
>> > + EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS,
>> > + card->ext_csd.generic_cmd6_time);
>> > +}
>> > +
>> > +/*
>> > * Activate wide bus and DDR if supported.
>> > */
>> > static int mmc_select_hs_ddr(struct mmc_card *card)
>> > @@ -993,6 +1035,54 @@ static int mmc_select_hs_ddr(struct mmc_card *card)
>> > return err;
>> > }
>> >
>> > +static int mmc_select_hs400(struct mmc_card *card)
>> > +{
>> > + struct mmc_host *host = card->host;
>> > + int err = 0;
>> > +
>> > + /*
>> > + * The bus width is set to only 8 DDR in HS400 mode
>>
>> Please rephrase the comment to something like:
>> "HS400 mode requires 8-bit bus width."
> As it is, it was from spec's description.
> But I think yours would be more clearable.
>
>>
>> > + */
>> > + if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
>> > + host->ios.bus_width == MMC_BUS_WIDTH_8))
>> > + return 0;
>> > +
>> > + /*
>> > + * Before setting BUS_WIDTH for dual data rate operation,
>> > + * HS_TIMING must be set to High Speed(0x1)
>> > + */
>>
>> Please rephrase comment:
>>
>> "Before switching to dual data rate operation for HS400, we need
>> revert from HS200 timing to regular HS timing."
> Ok.
>
>>
>> > + err = mmc_revert_to_hs(card);
>>
>> I don't think we need a separate function to handle the revert.
>> Please, just add the code here instead. While you do that, I suppose
>> we should combine the comment in that function into one comment here.
> OK, I don't oppose that.
>
>>
>> > + if (err) {
>> > + pr_warn("%s: switch to high-speed from hs200 failed, err:%d\n",
>> > + mmc_hostname(host), err);
>> > + return err;
>> > + }
>> > +
>> > + err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
>> > + EXT_CSD_BUS_WIDTH,
>> > + EXT_CSD_DDR_BUS_WIDTH_8,
>> > + card->ext_csd.generic_cmd6_time);
>> > + if (err) {
>> > + pr_warn("%s: switch to bus width for hs400 failed, err:%d\n",
>> > + mmc_hostname(host), err);
>> > + return err;
>> > + }
>> > +
>> > + err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
>> > + EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS400,
>> > + card->ext_csd.generic_cmd6_time);
>> > + if (err) {
>> > + pr_warn("%s: switch to hs400 failed, err:%d\n",
>> > + mmc_hostname(host), err);
>> > + return err;
>> > + }
>> > +
>> > + mmc_set_timing(host, MMC_TIMING_MMC_HS400);
>> > + mmc_set_bus_speed(card);
>> > +
>> > + return 0;
>> > +}
>> > +
>> > /*
>> > * For device supporting HS200 mode, the following sequence
>> > * should be done before executing the tuning process.
>> > @@ -1025,7 +1115,16 @@ static int mmc_select_hs200(struct mmc_card *card)
>> > EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS200,
>> > card->ext_csd.generic_cmd6_time,
>> > true, true, true);
>> > - if (!err)
>> > + if (err)
>> > + goto err;
>> > +
>> > + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400)
>> > + /*
>> > + * Timing should be adjusted to the HS400 target
>> > + * operation frequency for tuning process
>> > + */
>> > + mmc_set_timing(host, MMC_TIMING_MMC_HS400_TUNING);
>>
>> This seems strange. Do we really need a separate
>> MMC_TIMING_MMC_HS400_TUNING value?
> Spec. describes the HS400 selection sequence like below.
> <Quot>
> ...
> 6) Perform the Tuning Process at the HS400 target operating frequency
> (Note: tuning process in HS200 mode is required to synchronize the command response on the CMD line to CLK for HS400 operation).
> ...
> </Quot>
> That means target clock rate for tuning sequence can be different with HS200.
> Considering for that, it needs to distinguish.
I understand the spec now, thanks.
Still, I am not convinced we should handle this through the
MMC_TIMING* field. That will leave host drivers to do some magic clock
frequency calculation from their ->set_ios callbacks, just depending
on the MMC_TIMING_MMC_HS400_TUNING value.
I am also a bit concerned how MMC_TIMING_MMC_HS400_TUNING, would work
if/when we implement periodic re-tuning - triggered from the mmc core
layer.
What we really want to do, is to pretend we were to operate in
MMC_TIMING_MMC_HS400 and ask the host driver what the target frequency
would be in this case. Then set this frequency through
mmc_set_clock().
Then how do we ask the host driver about this frequency? Let's add a
new host_ops callback. We want it to be generic, so provide the
MMC_TIMING bit as a parameter. Additionally we want it to be optional
to implement, thus for those host drivers that supports the same
target frequency for HS200 as for HS400, they don't need to implement
it.
Would this be a way forward?
Kind regards
Ulf Hansson
>
>>
>> > + else
>> > mmc_set_timing(host, MMC_TIMING_MMC_HS200);
>> > }
>> > err:
>> > @@ -1070,7 +1169,7 @@ bus_speed:
>> >
>> > /*
>> > * Execute tuning sequence to seek the proper bus operating
>> > - * conditions for HS200, which sends CMD21 to the device.
>> > + * conditions for HS200 and HS400, which sends CMD21 to the device.
>> > */
>> > static int mmc_hs200_tuning(struct mmc_card *card)
>> > {
>> > @@ -1304,6 +1403,10 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
>> > err = mmc_hs200_tuning(card);
>> > if (err)
>> > goto err;
>> > +
>> > + err = mmc_select_hs400(card);
>> > + if (err)
>> > + goto err;
>> > } else if (mmc_card_hs(card)) {
>> > /* Select the desired bus width optionally */
>> > err = mmc_select_bus_width(card);
>> > diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
>> > index def6814..2b24c36 100644
>> > --- a/include/linux/mmc/card.h
>> > +++ b/include/linux/mmc/card.h
>> > @@ -110,6 +110,7 @@ struct mmc_ext_csd {
>> > u8 raw_pwr_cl_200_360; /* 237 */
>> > u8 raw_pwr_cl_ddr_52_195; /* 238 */
>> > u8 raw_pwr_cl_ddr_52_360; /* 239 */
>> > + u8 raw_pwr_cl_ddr_200_360; /* 253 */
>> > u8 raw_bkops_status; /* 246 */
>> > u8 raw_sectors[4]; /* 212 - 4 bytes */
>> >
>> > diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
>> > index 1ee3c10..cc716e4 100644
>> > --- a/include/linux/mmc/host.h
>> > +++ b/include/linux/mmc/host.h
>> > @@ -61,6 +61,8 @@ struct mmc_ios {
>> > #define MMC_TIMING_UHS_DDR50 7
>> > #define MMC_TIMING_MMC_DDR52 8
>> > #define MMC_TIMING_MMC_HS200 9
>> > +#define MMC_TIMING_MMC_HS400 10
>> > +#define MMC_TIMING_MMC_HS400_TUNING 11
>>
>> MMC_TIMING_MMC_HS400_TUNING ?
>>
>> >
>> > unsigned char signal_voltage; /* signalling voltage (1.8V or 3.3V) */
>> >
>> > @@ -274,6 +276,10 @@ struct mmc_host {
>> > #define MMC_CAP2_PACKED_CMD (MMC_CAP2_PACKED_RD | \
>> > MMC_CAP2_PACKED_WR)
>> > #define MMC_CAP2_NO_PRESCAN_POWERUP (1 << 14) /* Don't power up before scan */
>> > +#define MMC_CAP2_HS400_1_8V (1 << 15) /* Can support HS400 1.8V */
>> > +#define MMC_CAP2_HS400_1_2V (1 << 16) /* Can support HS400 1.2V */
>> > +#define MMC_CAP2_HS400 (MMC_CAP2_HS400_1_8V | \
>> > + MMC_CAP2_HS400_1_2V)
>> >
>> > mmc_pm_flag_t pm_caps; /* supported pm features */
>> >
>> > @@ -486,11 +492,18 @@ static inline int mmc_card_uhs(struct mmc_card *card)
>> >
>> > static inline bool mmc_card_hs200(struct mmc_card *card)
>> > {
>> > - return card->host->ios.timing == MMC_TIMING_MMC_HS200;
>> > + return card->host->ios.timing == MMC_TIMING_MMC_HS200 ||
>> > + card->host->ios.timing == MMC_TIMING_MMC_HS400_TUNING;
>>
>> MMC_TIMING_MMC_HS400_TUNING ?
> It also indicates that card is currently in HS200 mode with the result of setting HS_TIMING'.
>
> Thanks,
> Seungwon Jeon
>
>>
>> > }
>> >
>> > static inline bool mmc_card_ddr52(struct mmc_card *card)
>> > {
>> > return card->host->ios.timing == MMC_TIMING_MMC_DDR52;
>> > }
>> > +
>> > +static inline bool mmc_card_hs400(struct mmc_card *card)
>> > +{
>> > + return card->host->ios.timing == MMC_TIMING_MMC_HS400;
>> > +}
>> > +
>> > #endif /* LINUX_MMC_HOST_H */
>> > diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
>> > index f429f13..64ec963 100644
>> > --- a/include/linux/mmc/mmc.h
>> > +++ b/include/linux/mmc/mmc.h
>> > @@ -325,6 +325,7 @@ struct _mmc_csd {
>> > #define EXT_CSD_POWER_OFF_LONG_TIME 247 /* RO */
>> > #define EXT_CSD_GENERIC_CMD6_TIME 248 /* RO */
>> > #define EXT_CSD_CACHE_SIZE 249 /* RO, 4 bytes */
>> > +#define EXT_CSD_PWR_CL_DDR_200_360 253 /* RO */
>> > #define EXT_CSD_TAG_UNIT_SIZE 498 /* RO */
>> > #define EXT_CSD_DATA_TAG_SUPPORT 499 /* RO */
>> > #define EXT_CSD_MAX_PACKED_WRITES 500 /* RO */
>> > @@ -354,7 +355,6 @@ struct _mmc_csd {
>> > #define EXT_CSD_CMD_SET_SECURE (1<<1)
>> > #define EXT_CSD_CMD_SET_CPSECURE (1<<2)
>> >
>> > -#define EXT_CSD_CARD_TYPE_MASK 0x3F /* Mask out reserved bits */
>> > #define EXT_CSD_CARD_TYPE_HS_26 (1<<0) /* Card can run at 26MHz */
>> > #define EXT_CSD_CARD_TYPE_HS_52 (1<<1) /* Card can run at 52MHz */
>> > #define EXT_CSD_CARD_TYPE_HS (EXT_CSD_CARD_TYPE_HS_26 | \
>> > @@ -370,6 +370,10 @@ struct _mmc_csd {
>> > /* SDR mode @1.2V I/O */
>> > #define EXT_CSD_CARD_TYPE_HS200 (EXT_CSD_CARD_TYPE_HS200_1_8V | \
>> > EXT_CSD_CARD_TYPE_HS200_1_2V)
>> > +#define EXT_CSD_CARD_TYPE_HS400_1_8V (1<<6) /* Card can run at 200MHz DDR, 1.8V */
>> > +#define EXT_CSD_CARD_TYPE_HS400_1_2V (1<<7) /* Card can run at 200MHz DDR, 1.2V */
>> > +#define EXT_CSD_CARD_TYPE_HS400 (EXT_CSD_CARD_TYPE_HS400_1_8V | \
>> > + EXT_CSD_CARD_TYPE_HS400_1_2V)
>> >
>> > #define EXT_CSD_BUS_WIDTH_1 0 /* Card is in 1 bit mode */
>> > #define EXT_CSD_BUS_WIDTH_4 1 /* Card is in 4 bit mode */
>> > @@ -380,6 +384,7 @@ struct _mmc_csd {
>> > #define EXT_CSD_TIMING_BC 0 /* Backwards compatility */
>> > #define EXT_CSD_TIMING_HS 1 /* High speed */
>> > #define EXT_CSD_TIMING_HS200 2 /* HS200 */
>> > +#define EXT_CSD_TIMING_HS400 3 /* HS400 */
>> >
>> > #define EXT_CSD_SEC_ER_EN BIT(0)
>> > #define EXT_CSD_SEC_BD_BLK_EN BIT(2)
>> > --
>> > 1.7.0.4
>> >
>> >
>>
>> Kind regards
>> Ulf Hansson
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