[U-Boot] [RFC 2/3][v4] mmc: SEND_OP_COND considers card capabilities (voltage)

[Gary Thomas <samoht.yrag@gmail.com>]

On 2011-04-13 05:24, Andy Fleming wrote:
> On Fri, Mar 11, 2011 at 6:01 AM, Raffaele Recalcati
> <lamiaposta71@gmail.com>  wrote:
>> From: Raffaele Recalcati<raffaele.recalcati@bticino.it>
>>
>> The first SEND_OP_COND (CMD1) command added is used to ask card capabilities.
>> After it an AND operation is done between card capabilities and host
>> capabilities (at the moment only for the voltage field).
>> Finally the correct value is sent to the MMC, waiting that the card
>> exits from busy state.
>>
>> Signed-off-by: Raffaele Recalcati<raffaele.recalcati@bticino.it>
>> ---
>>   drivers/mmc/mmc.c |   19 +++++++++++++++++--
>>   include/mmc.h     |    2 ++
>>   2 files changed, 19 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
>> index fc1792a..5bea476 100644
>> --- a/drivers/mmc/mmc.c
>> +++ b/drivers/mmc/mmc.c
>> @@ -351,17 +351,32 @@ sd_send_op_cond(struct mmc *mmc)
>>
>>   int mmc_send_op_cond(struct mmc *mmc)
>>   {
>> -       int timeout = 1000;
>> +       int timeout = 10000;
>>         struct mmc_cmd cmd;
>>         int err;
>>
>>         /* Some cards seem to need this */
>>         mmc_go_idle(mmc);
>>
>> +       /* Asking to the card its capabilities */
>> +       cmd.cmdidx = MMC_CMD_SEND_OP_COND;
>> +       cmd.resp_type = MMC_RSP_R3;
>> +       cmd.cmdarg = 0;
>> +       cmd.flags = 0;
>> +
>> +       err = mmc_send_cmd(mmc,&cmd, NULL);
>> +
>> +       if (err)
>> +               return err;
>> +
>> +       udelay(1000);
>> +
>>         do {
>>                 cmd.cmdidx = MMC_CMD_SEND_OP_COND;
>>                 cmd.resp_type = MMC_RSP_R3;
>> -               cmd.cmdarg = OCR_HCS | mmc->voltages;
>> +               cmd.cmdarg = ((mmc->voltages&
>> +                             (cmd.response[0]&  OCR_VOLTAGE_MASK)) |
>> +                             (cmd.response[0]&  OCR_ACCESS_MODE));
>
>
> My concern here is that OCR_HCS has been dropped. I thought it was
> necessary to query the HCS abilities.
>
> I'm guessing I'm missing something, or that it's not needed, so I will
> apply this patch, and we'll see if anyone has issues.

I just tried this on my eMMC chip (THGBM1G5D2EBAI7) and without the OCR_HCS bit set, the
device gets totally hosed.  Only a power cycle will fix it.

Adding it back like this fixes the problem:
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 21aedba..76117da 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -446,7 +446,7 @@ int mmc_send_op_cond(struct mmc *mmc)
                 cmd.cmdidx = MMC_CMD_SEND_OP_COND;
                 cmd.resp_type = MMC_RSP_R3;
                 cmd.cmdarg = (mmc_host_is_spi(mmc) ? 0 :
-                               (mmc->voltages &
+                               OCR_HCS | (mmc->voltages &
                                 (cmd.response[0] & OCR_VOLTAGE_MASK)) |
                                 (cmd.response[0] & OCR_ACCESS_MODE));
                 cmd.flags = 0;