* confusion regarding the CMD19 and CMD21 in eMMC/SD card spec
@ 2011-09-15 11:58 Girish K S
2011-09-15 16:23 ` Philip Rakity
0 siblings, 1 reply; 7+ messages in thread
From: Girish K S @ 2011-09-15 11:58 UTC (permalink / raw)
To: linux-arm-kernel
Dear all,
The eMMC 4.5 specification mentions that the CMD21 in
class 2 is a SEND_TUNING BLOCK command. where as the SD card
specification
in the given link says CMD19 in class 2 is the SEND_TUNING_BLOCK
http://www.scribd.com/doc/50685191/53/Figure-4-8-Send-Tuning-Block-Command.
Also the implementation in the drivers/mmc/host/sdhci.c uses the CMD19
as the SEND_TUNING_BLOCK.
Can anybody clarify why there is overlapping in this command number.
May be my understand is wrong.
In the MMC spec the CMD19 is BUS_TEST_W in class 0 and CMD21 is
reserved till eMMC 4.41 version.
But in the SD specification (given link) CMD19 is SEND_TUNING_BLOCK
and CMD21 is reserved.
Thanks and regards
Girish K S
^ permalink raw reply [flat|nested] 7+ messages in thread* confusion regarding the CMD19 and CMD21 in eMMC/SD card spec
2011-09-15 11:58 confusion regarding the CMD19 and CMD21 in eMMC/SD card spec Girish K S
@ 2011-09-15 16:23 ` Philip Rakity
2011-09-16 4:11 ` Girish K S
0 siblings, 1 reply; 7+ messages in thread
From: Philip Rakity @ 2011-09-15 16:23 UTC (permalink / raw)
To: linux-arm-kernel
Different committee's --- Different standards.
There is no issue with overlap.
On Sep 15, 2011, at 4:58 AM, Girish K S wrote:
> Dear all,
> The eMMC 4.5 specification mentions that the CMD21 in
> class 2 is a SEND_TUNING BLOCK command. where as the SD card
> specification
> in the given link says CMD19 in class 2 is the SEND_TUNING_BLOCK
> http://www.scribd.com/doc/50685191/53/Figure-4-8-Send-Tuning-Block-Command.
> Also the implementation in the drivers/mmc/host/sdhci.c uses the CMD19
> as the SEND_TUNING_BLOCK.
> Can anybody clarify why there is overlapping in this command number.
> May be my understand is wrong.
>
> In the MMC spec the CMD19 is BUS_TEST_W in class 0 and CMD21 is
> reserved till eMMC 4.41 version.
> But in the SD specification (given link) CMD19 is SEND_TUNING_BLOCK
> and CMD21 is reserved.
>
> Thanks and regards
> Girish K S
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo at vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 7+ messages in thread
* confusion regarding the CMD19 and CMD21 in eMMC/SD card spec
2011-09-15 16:23 ` Philip Rakity
@ 2011-09-16 4:11 ` Girish K S
2011-09-16 4:47 ` Aaron Lu
0 siblings, 1 reply; 7+ messages in thread
From: Girish K S @ 2011-09-16 4:11 UTC (permalink / raw)
To: linux-arm-kernel
but there is only one host controller to handle these commands.
the generic sdhci driver has cmd19 hard coded, thats the reason I
asked the question.
you can also check it in the function sdhci_execute_tuning it is hard coded as
cmd.opcode = MMC_SEND_TUNING_BLOCK; where the macro value is 19.
So in case of SD card insertion it will send a SEND_TUNING_BLOCK
command to the device. but if
MMC card is inserted then it will send a BUS_TEST_W command to the device.
correct me if i am wrong
regards
Girish
On 15 September 2011 21:53, Philip Rakity <prakity@marvell.com> wrote:
>
> Different committee's --- Different standards.
>
> There is no issue with overlap.
>
>
> On Sep 15, 2011, at 4:58 AM, Girish K S wrote:
>
>> Dear all,
>> ? ? ? ? ? ? The eMMC 4.5 specification mentions that the CMD21 in
>> class 2 is a SEND_TUNING BLOCK command. where as the SD card
>> specification
>> in the given link says CMD19 in class 2 is the SEND_TUNING_BLOCK
>> http://www.scribd.com/doc/50685191/53/Figure-4-8-Send-Tuning-Block-Command.
>> Also the implementation in the drivers/mmc/host/sdhci.c uses the CMD19
>> as the SEND_TUNING_BLOCK.
>> Can anybody clarify why there is overlapping in this command number.
>> May be my understand is wrong.
>>
>> In the MMC spec the CMD19 is BUS_TEST_W in class 0 and CMD21 is
>> reserved till eMMC 4.41 version.
>> But in the SD specification (given link) CMD19 is SEND_TUNING_BLOCK
>> and CMD21 is reserved.
>>
>> Thanks and regards
>> Girish K S
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>> the body of a message to majordomo at vger.kernel.org
>> More majordomo info at ?http://vger.kernel.org/majordomo-info.html
>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* confusion regarding the CMD19 and CMD21 in eMMC/SD card spec
2011-09-16 4:11 ` Girish K S
@ 2011-09-16 4:47 ` Aaron Lu
2011-09-16 5:30 ` Girish K S
0 siblings, 1 reply; 7+ messages in thread
From: Aaron Lu @ 2011-09-16 4:47 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, Sep 16, 2011 at 09:41:04AM +0530, Girish K S wrote:
> but there is only one host controller to handle these commands.
> the generic sdhci driver has cmd19 hard coded, thats the reason I
> asked the question.
> you can also check it in the function sdhci_execute_tuning it is hard coded as
> cmd.opcode = MMC_SEND_TUNING_BLOCK; where the macro value is 19.
> So in case of SD card insertion it will send a SEND_TUNING_BLOCK
> command to the device. but if
> MMC card is inserted then it will send a BUS_TEST_W command to the device.
sdhci_execute_tuning will only be called if the inserted card is a sd card
and it is operating at SDR104 or SDR50 mode(UHS-I).
The host's tuning function is called from the mmc_sd_init_uhs_card,
and for a mmc card, there is no chance of that function being called.
-Aaron
^ permalink raw reply [flat|nested] 7+ messages in thread
* confusion regarding the CMD19 and CMD21 in eMMC/SD card spec
2011-09-16 4:47 ` Aaron Lu
@ 2011-09-16 5:30 ` Girish K S
2011-09-16 5:57 ` Aaron Lu
0 siblings, 1 reply; 7+ messages in thread
From: Girish K S @ 2011-09-16 5:30 UTC (permalink / raw)
To: linux-arm-kernel
Hello Aaron Lu,
please check the mmc 4.5 specification CMD21 is
tuning command.
regards
Girish K S
On 16 September 2011 10:17, Aaron Lu <aaron.lu@amd.com> wrote:
> On Fri, Sep 16, 2011 at 09:41:04AM +0530, Girish K S wrote:
>> but there is only one host controller to handle these commands.
>> the generic sdhci driver has cmd19 hard coded, thats the reason I
>> asked the question.
>> you can also check it in the function sdhci_execute_tuning it is hard coded as
>> cmd.opcode = MMC_SEND_TUNING_BLOCK; where the macro value is 19.
>> So in case of SD card insertion it will send a SEND_TUNING_BLOCK
>> command to the device. but if
>> MMC card is inserted then it will send a BUS_TEST_W command to the device.
>
> sdhci_execute_tuning will only be called if the inserted card is a sd card
> and it is operating at SDR104 or SDR50 mode(UHS-I).
>
> The host's tuning function is called from the mmc_sd_init_uhs_card,
> and for a mmc card, there is no chance of that function being called.
>
> -Aaron
>
>
^ permalink raw reply [flat|nested] 7+ messages in thread* confusion regarding the CMD19 and CMD21 in eMMC/SD card spec
2011-09-16 5:30 ` Girish K S
@ 2011-09-16 5:57 ` Aaron Lu
2011-09-16 6:14 ` Girish K S
0 siblings, 1 reply; 7+ messages in thread
From: Aaron Lu @ 2011-09-16 5:57 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, Sep 16, 2011 at 11:00:12AM +0530, Girish K S wrote:
> Hello Aaron Lu,
Hi,
> please check the mmc 4.5 specification CMD21 is
> tuning command.
So you are using a mmc card with a sd host?
-Aaron
^ permalink raw reply [flat|nested] 7+ messages in thread
* confusion regarding the CMD19 and CMD21 in eMMC/SD card spec
2011-09-16 5:57 ` Aaron Lu
@ 2011-09-16 6:14 ` Girish K S
0 siblings, 0 replies; 7+ messages in thread
From: Girish K S @ 2011-09-16 6:14 UTC (permalink / raw)
To: linux-arm-kernel
our host controller supports both
SD/MMC. single controller to read both cards.
On 16 September 2011 11:27, Aaron Lu <aaron.lu@amd.com> wrote:
> On Fri, Sep 16, 2011 at 11:00:12AM +0530, Girish K S wrote:
>> Hello Aaron Lu,
> Hi,
>
>> ? ? ? ? ? ? ? ? ? ? please check the mmc 4.5 specification CMD21 is
>> tuning command.
>
> So you are using a mmc card with a sd host?
>
> -Aaron
>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2011-09-16 6:14 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
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2011-09-15 11:58 confusion regarding the CMD19 and CMD21 in eMMC/SD card spec Girish K S
2011-09-15 16:23 ` Philip Rakity
2011-09-16 4:11 ` Girish K S
2011-09-16 4:47 ` Aaron Lu
2011-09-16 5:30 ` Girish K S
2011-09-16 5:57 ` Aaron Lu
2011-09-16 6:14 ` Girish K S
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