Re: [PATCH v3 1/6] mmc: add define for R1 response without CRC

[Jaehoon Chung]

On 09/21/2016 03:00 PM, Wolfram Sang wrote:
> On Tue, Sep 20, 2016 at 06:25:37PM +0900, Jaehoon Chung wrote:
>> Hi Wolfram,
>>
>> On 09/20/2016 05:57 AM, Wolfram Sang wrote:
>>> The core uses it for polling. Give drivers a proper define handle this
>>> case like for other response types.
>>>
>>> Signed-off-by: Wolfram Sang 
>>> ---
>>>  include/linux/mmc/core.h | 3 +++
>>>  1 file changed, 3 insertions(+)
>>>
>>> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
>>> index b01e77de1a74de..4caee099b63a28 100644
>>> --- a/include/linux/mmc/core.h
>>> +++ b/include/linux/mmc/core.h
>>> @@ -55,6 +55,9 @@ struct mmc_command {
>>>  #define MMC_RSP_R6 (MMC_RSP_PRESENT|MMC_RSP_CRC|MMC_RSP_OPCODE)
>>>  #define MMC_RSP_R7 (MMC_RSP_PRESENT|MMC_RSP_CRC|MMC_RSP_OPCODE)
>>>  
>>> +/* Can be used by core to poll after switch to MMC HS mode */
>>> +#define MMC_RSP_R1_NO_CRC  (MMC_RSP_PRESENT|MMC_RSP_OPCODE)
>>
>> MMC_RSP_RQ_NO_CRC is described at Specification?
> 
> Yes. JEDEC eMMC Spec v5.1, chapter 6.6.2, in the note:
> 
> "NOTE While the actual timing change is done, the behavior of any
> command sent (like CMD13) cannot be guaranteed due to the asynchronous
> operation. Therefore it is not recommended to use CMD13 to check the
> busy completion of the timing change indication. In case CMD13 is used
> the host must ignore CRC errors, if appear."

Thanks for noticing this. I read the spec again.

Best Regards,
Jaehoon Chung

> 
> And the MMC core does that. In mmc_ops.c:
> 
> 70 if (ignore_crc)
> 71 cmd.flags &= ~MMC_RSP_CRC;
> 
> And ignore_crc is used in mmc.c (last 'true' parameter):
> 
> 1023 err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> 1024EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS,
> 1025card->ext_csd.generic_cmd6_time,
> 1026true, false, true);
> 
> This is why I put the comment above the define.
> 

Re: [PATCH v3 1/6] mmc: add define for R1 response without CRC

[Jaehoon Chung]

Hi Wolfram,

On 09/20/2016 05:57 AM, Wolfram Sang wrote:
> The core uses it for polling. Give drivers a proper define handle this
> case like for other response types.
> 
> Signed-off-by: Wolfram Sang 
> ---
>  include/linux/mmc/core.h | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
> index b01e77de1a74de..4caee099b63a28 100644
> --- a/include/linux/mmc/core.h
> +++ b/include/linux/mmc/core.h
> @@ -55,6 +55,9 @@ struct mmc_command {
>  #define MMC_RSP_R6   (MMC_RSP_PRESENT|MMC_RSP_CRC|MMC_RSP_OPCODE)
>  #define MMC_RSP_R7   (MMC_RSP_PRESENT|MMC_RSP_CRC|MMC_RSP_OPCODE)
>  
> +/* Can be used by core to poll after switch to MMC HS mode */
> +#define MMC_RSP_R1_NO_CRC(MMC_RSP_PRESENT|MMC_RSP_OPCODE)

MMC_RSP_RQ_NO_CRC is described at Specification?

Best Regards,
Jaehoon Chung

> +
>  #define mmc_resp_type(cmd)   ((cmd)->flags & 
> (MMC_RSP_PRESENT|MMC_RSP_136|MMC_RSP_CRC|MMC_RSP_BUSY|MMC_RSP_OPCODE))
>  
>  /*
> 

[PATCH v3 1/6] mmc: add define for R1 response without CRC

[Wolfram Sang]

The core uses it for polling. Give drivers a proper define handle this
case like for other response types.

Signed-off-by: Wolfram Sang 
---
 include/linux/mmc/core.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index b01e77de1a74de..4caee099b63a28 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -55,6 +55,9 @@ struct mmc_command {
 #define MMC_RSP_R6 (MMC_RSP_PRESENT|MMC_RSP_CRC|MMC_RSP_OPCODE)
 #define MMC_RSP_R7 (MMC_RSP_PRESENT|MMC_RSP_CRC|MMC_RSP_OPCODE)
 
+/* Can be used by core to poll after switch to MMC HS mode */
+#define MMC_RSP_R1_NO_CRC  (MMC_RSP_PRESENT|MMC_RSP_OPCODE)
+
 #define mmc_resp_type(cmd) ((cmd)->flags & 
(MMC_RSP_PRESENT|MMC_RSP_136|MMC_RSP_CRC|MMC_RSP_BUSY|MMC_RSP_OPCODE))
 
 /*
-- 
2.9.3