On Dec 6, 2010, at 8:09 PM, Zhangfei Gao wrote:
> On Mon, Dec 6, 2010 at 10:36 PM, zhangfei gao <zhangfei.gao@xxxxxxxxx> wrote:
>> On Mon, Dec 6, 2010 at 10:10 PM, Philip Rakity <prakity@xxxxxxxxxxx> wrote:
>>>
>>> On Dec 6, 2010, at 4:15 AM, Zhangfei Gao wrote:
>>>
>>>> From f2194b46c2c3ded86009d36a4a8b4eebb7d0b9eb Mon Sep 17 00:00:00 2001
>>>> From: Zhangfei Gao <zhangfei.gao@xxxxxxxxxxx>
>>>> Date: Fri, 3 Dec 2010 07:21:15 -0500
>>>> Subject: [PATCH] mmc: sdhci support emmc ddr50 mode
>>>>
>>>> 1. spec 3.0 does not claim support 1.2v ddr mode
>>>> 2. Call back function set_power is added, since some controller count
>>>> on external pmic to provide power
>>>>
>>>> Signed-off-by: Zhangfei Gao <zhangfei.gao@xxxxxxxxxxx>
>>>> ---
>>>> drivers/mmc/core/core.c | 8 ++++++++
>>>> drivers/mmc/host/sdhci.c | 36 +++++++++++++++++++++++++++++++++++-
>>>> drivers/mmc/host/sdhci.h | 14 ++++++++++++--
>>>> include/linux/mmc/mmc.h | 1 +
>>>> include/linux/mmc/sdhci.h | 2 ++
>>>> 5 files changed, 58 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>>>> index 8bf542c..8f172cd 100644
>>>> --- a/drivers/mmc/core/core.c
>>>> +++ b/drivers/mmc/core/core.c
>>>> @@ -1573,6 +1573,14 @@ void mmc_rescan(struct work_struct *work)
>>>> */
>>>> err = mmc_send_op_cond(host, 0, &ocr);
>>>> if (!err) {
>>>> + if ((ocr & MMC_CARD_1_8V)
>>>> + && (host->ocr_avail & MMC_CARD_1_8V)) {
>>>> + /* switch voltage to 1.8v */
>>>> + mmc_power_off(host);
>>>> + host->ocr = ocr & host->ocr_avail;
>>>> + mmc_power_up(host);
>>>> + }
>>>> +
>>>
>>> is the 1.2v case missing ?
>> ocr does not support 1.2.
>>>
>>> /*
>>> * Mask off any voltages we don't support and select
>>> * the lowest voltage
>>> */
>>> u32 mmc_select_voltage(struct mmc_host *host, u32 ocr)
>>>
>>> Doesn't this code already handle the voltage correctly ?
>> mmc_select_voltage can not meet the requirement, if switch voltage,
>> power down and power up is needed, time delay is required waiting for
>> voltage to be stable.
>>
>>>
>>>
>>>> if (mmc_attach_mmc(host, ocr))
>>>> mmc_power_off(host);
>>>> goto out;
>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>>> index a25db42..b7ad2f6 100644
>>>> --- a/drivers/mmc/host/sdhci.c
>>>> +++ b/drivers/mmc/host/sdhci.c
>>>> @@ -982,6 +982,22 @@ static void sdhci_finish_command(struct sdhci_host *host)
>>>> host->cmd = NULL;
>>>> }
>>>>
>>>> +static void sdhci_set_ddr(struct sdhci_host *host, unsigned int ddr)
>>>> +{
>>>> + u16 con;
>>>> +
>>>> + if (ddr == MMC_SDR_MODE)
>>>> + return;
>>>> +
>>>> + con = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>>>> + if (con & SDHCI_CTRL2_1_8V) {
>>>> + con &= ~SDHCI_CTRL2_UHS_MASK;
>>>> + if (ddr & MMC_1_8V_DDR_MODE)
>>>> + con |= SDHCI_CTRL2_DDR50;
>>>> + sdhci_writew(host, con, SDHCI_HOST_CONTROL2);
>>>> + }
>>>> +}
>>>> +
>>>
>>>
>>> The host controller should not enable the CAP if 1.8V is not supported. DDR should not be
>>> invoked if CAP is not set. Thus
>>
>> set_ddr is called with para ddr, it would not enter here if CAP is not set.
>>>
>>>> + if (con & SDHCI_CTRL2_1_8V) {
>>>
>>> and
>>>> + if (ddr & MMC_1_8V_DDR_MODE)
>>>
>>> are not needed.
>>>
>>> This code should move to driver specific function since tuning may be done on some systems and
>>> some systems (not mmp2) may need to delay the 5ms for voltage to be stable. Would prefer a
>>> host->ops callback.
>> 5ms is considered in power up, that's the reason not put in set_ios
>> with call back.
>>>
>>>> static void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
>>>> {
>>>> int div;
>>>> @@ -1080,6 +1096,17 @@ static void sdhci_set_power(struct sdhci_host
>>>> *host, unsigned short power)
>>>> return;
>>>> }
>>>>
>>>> + if (pwr == SDHCI_POWER_180) {
>
> Could add one more condition here
> if ((host->mmc->caps & MMC_CAP_1_8V_DDR) &&
> (pwr == SDHCI_POWER_180)) {
>
>>>> + u16 con;
>>>> +
>>>> + con = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>>>> + con |= SDHCI_CTRL2_1_8V;
>>>> + sdhci_writew(host, con, SDHCI_HOST_CONTROL2);
>>>> +
>>>> + if (host->ops->set_power)
>>>> + host->ops->set_power(host, pwr);
>>>> + }
>>>> +
>>>
>>> This code should be moved to sdhci_set_ddr (aboe). Not needed if voltage is 1.8v and card
>>> is not running ddr.
>> No defect to set SDHCI_CTRL2_1_8V if choose 1.8v.
>>
>>>
>>>> /*
>>>> * Spec says that we should clear the power reg before setting
>>>> * a new value. Some controllers don't seem to like this though.
>>>> @@ -1176,6 +1203,7 @@ static void sdhci_set_ios(struct mmc_host *mmc,
>>>> struct mmc_ios *ios)
>>>> }
>>>>
>>>> sdhci_set_clock(host, ios->clock);
>>>> + sdhci_set_ddr(host, ios->ddr);
>>>>
>>>> if (ios->power_mode == MMC_POWER_OFF)
>>>> sdhci_set_power(host, -1);
>>>> @@ -1736,7 +1764,7 @@ EXPORT_SYMBOL_GPL(sdhci_alloc_host);
>>>> int sdhci_add_host(struct sdhci_host *host)
>>>> {
>>>> struct mmc_host *mmc;
>>>> - unsigned int caps;
>>>> + unsigned int caps, caps_h;
>>>> int ret;
>>>>
>>>> WARN_ON(host == NULL);
>>>> @@ -1761,6 +1789,12 @@ int sdhci_add_host(struct sdhci_host *host)
>>>>
>>>> caps = (host->quirks & SDHCI_QUIRK_MISSING_CAPS) ? host->caps :
>>>> sdhci_readl(host, SDHCI_CAPABILITIES);
>>>> + caps_h = sdhci_readl(host, SDHCI_CAPABILITIES_H);
>>>> +
>>>> + if (caps & SDHCI_CAN_VDD_180) {
>>>> + if (caps_h & SDHCI_CAN_SDR50)
>>>> + mmc->caps |= (MMC_CAP_1_8V_DDR);
>>>> + }
>>>>
>>>> if (host->quirks & SDHCI_QUIRK_FORCE_DMA)
>>>> host->flags |= SDHCI_USE_SDMA;
>>>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>>>> index b689cc6..28c460a 100644
>>>> --- a/drivers/mmc/host/sdhci.h
>>>> +++ b/drivers/mmc/host/sdhci.h
>>>> @@ -144,7 +144,14 @@
>>>>
>>>> #define SDHCI_ACMD12_ERR 0x3C
>>>>
>>>> -/* 3E-3F reserved */
>>>> +#define SDHCI_HOST_CONTROL2 0x3E
>>>> +#define SDHCI_CTRL2_UHS_MASK 0x0007
>>>> +#define SDHCI_CTRL2_SDR12 0x0000
>>>> +#define SDHCI_CTRL2_SDR25 0x0001
>>>> +#define SDHCI_CTRL2_SDR50 0x0002
>>>> +#define SDHCI_CTRL2_SDR104 0x0003
>>>> +#define SDHCI_CTRL2_DDR50 0x0004
>>>> +#define SDHCI_CTRL2_1_8V 0x0008
>>>>
>>>> #define SDHCI_CAPABILITIES 0x40
>>>> #define SDHCI_TIMEOUT_CLK_MASK 0x0000003F
>>>> @@ -165,7 +172,10 @@
>>>> #define SDHCI_CAN_VDD_180 0x04000000
>>>> #define SDHCI_CAN_64BIT 0x10000000
>>>>
>>>> -/* 44-47 reserved for more caps */
>>>> +#define SDHCI_CAPABILITIES_H 0x44
>>>> +#define SDHCI_CAN_SDR50 0x00000001
>>>> +#define SDHCI_CAN_SDR104 0x00000002
>>>> +#define SDHCI_CAN_DDR50 0x00000004
>>>>
>>>> #define SDHCI_MAX_CURRENT 0x48
>>>>
>>>> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
>>>> index 956fbd8..bd09b19 100644
>>>> --- a/include/linux/mmc/mmc.h
>>>> +++ b/include/linux/mmc/mmc.h
>>>> @@ -202,6 +202,7 @@ struct _mmc_csd {
>>>> * OCR bits are mostly in host.h
>>>> */
>>>> #define MMC_CARD_BUSY 0x80000000 /* Card Power up status bit */
>>>> +#define MMC_CARD_1_8V 0x00000080 /* Card 1.70-1.95V support bit */
>>>>
>>>> /*
>>>> * Card Command Classes (CCC)
>>>> diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
>>>> index 86e8380..57bcda9 100644
>>>> --- a/include/linux/mmc/sdhci.h
>>>> +++ b/include/linux/mmc/sdhci.h
>>>> @@ -163,6 +163,8 @@ struct sdhci_ops {
>>>> void (*platform_send_init_74_clocks)(struct sdhci_host *host,
>>>> u8 power_mode);
>>>> unsigned int (*get_ro)(struct sdhci_host *host);
>>>> + unsigned int (*set_power)(struct sdhci_host *host,
>>>> + unsigned short power);
>>>> };
>>>>
>>>>
>>>> --
>>>> 1.7.0.4
>>>>
>>>> Update the condition of voltage switch.
>>>> + if ((ocr & MMC_CARD_1_8V)
>>>> + && (host->ocr_avail & MMC_CARD_1_8V)) {
>>>> + /* switch voltage to 1.8v */
>>>>
>>>> Any comments are welcome.
>>>> --
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>>>
>>>
>>
NAK
There are two voltages -- the voltage to the card and the voltage used for signaling.
The voltage of the card is programmed using mmc_set_voltage. It can be 3.3, 1.8v etc
this voltage is controlled via the host control register 0x28.
the voltage used for signaling is controlled via the host control register 2 (0x3e). moving
to ddr requires that this voltage be signaled to the card (CMD11) and and changed via
host control register 2. The flowchart figure 3.10 -- page 104 shows the sequence that
is needed.
What is missing in core/ is
a) support for CMD11
b) correct implementation for changing the signaling voltage for uhs modes
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