* [PATCH] mmc: host: don't access at boot partition when mode is HS200/HS400.
@ 2014-08-13 4:46 Jaehoon Chung
2014-08-13 13:27 ` Alex Lemberg
0 siblings, 1 reply; 3+ messages in thread
From: Jaehoon Chung @ 2014-08-13 4:46 UTC (permalink / raw)
To: linux-mmc; +Cc: Chris Ball, Ulf Hansson, Jaehoon Chung
HS200/HS400 mode is not supported during boot operation.
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
---
include/linux/mmc/host.h | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 7960424..ce5db96 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -445,6 +445,10 @@ static inline int mmc_host_cmd23(struct mmc_host *host)
static inline int mmc_boot_partition_access(struct mmc_host *host)
{
+ /* HS200 & HS400 mode is not supported during boot operation */
+ if (host->caps2 & (MMC_CAP2_HS200 | MMC_CAP2_HS400))
+ return 0;
+
return !(host->caps2 & MMC_CAP2_BOOTPART_NOACC);
}
--
1.7.9.5
^ permalink raw reply related [flat|nested] 3+ messages in thread
* RE: [PATCH] mmc: host: don't access at boot partition when mode is HS200/HS400.
2014-08-13 4:46 [PATCH] mmc: host: don't access at boot partition when mode is HS200/HS400 Jaehoon Chung
@ 2014-08-13 13:27 ` Alex Lemberg
2014-08-13 13:36 ` Jaehoon Chung
0 siblings, 1 reply; 3+ messages in thread
From: Alex Lemberg @ 2014-08-13 13:27 UTC (permalink / raw)
To: Jaehoon Chung; +Cc: Chris Ball, Ulf Hansson, linux-mmc
Hi,
HS200 & HS400 mode is not supported during boot operation, but I think this specific change
will prevent any boot operation or access to boot partition on all hosts with HS200 & HS400 capabilities in general,
even in case then the eMMC card is DDR52 type.
The actual bus clock speed need to be checked in order to prevent/allow boot operation, but not the host capabilities.
As for regular R/W access to boot partition, as far as I see from the JEDEC spec - it can work in HS200 & HS400 modes, so no change is required.
Please correct me if I wrong.
Thanks,
Alex
> -----Original Message-----
> From: linux-mmc-owner@vger.kernel.org [mailto:linux-mmc-
> owner@vger.kernel.org] On Behalf Of Jaehoon Chung
> Sent: Wednesday, August 13, 2014 7:46 AM
> To: linux-mmc
> Cc: Chris Ball; Ulf Hansson; Jaehoon Chung
> Subject: [PATCH] mmc: host: don't access at boot partition when mode is
> HS200/HS400.
>
> HS200/HS400 mode is not supported during boot operation.
>
> Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
> ---
> include/linux/mmc/host.h | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index
> 7960424..ce5db96 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -445,6 +445,10 @@ static inline int mmc_host_cmd23(struct mmc_host
> *host)
>
> static inline int mmc_boot_partition_access(struct mmc_host *host) {
> + /* HS200 & HS400 mode is not supported during boot operation */
> + if (host->caps2 & (MMC_CAP2_HS200 | MMC_CAP2_HS400))
> + return 0;
> +
> return !(host->caps2 & MMC_CAP2_BOOTPART_NOACC); }
>
> --
> 1.7.9.5
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the
> body of a message to majordomo@vger.kernel.org More majordomo info at
> http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] mmc: host: don't access at boot partition when mode is HS200/HS400.
2014-08-13 13:27 ` Alex Lemberg
@ 2014-08-13 13:36 ` Jaehoon Chung
0 siblings, 0 replies; 3+ messages in thread
From: Jaehoon Chung @ 2014-08-13 13:36 UTC (permalink / raw)
To: Alex Lemberg; +Cc: Chris Ball, Ulf Hansson, linux-mmc
Hi, Alex.
On 08/13/2014 10:27 PM, Alex Lemberg wrote:
> Hi,
>
> HS200 & HS400 mode is not supported during boot operation, but I think this specific change
> will prevent any boot operation or access to boot partition on all hosts with HS200 & HS400 capabilities in general,
> even in case then the eMMC card is DDR52 type.
Right, even if host capabilities is supported HS200 & HS400, card couldn't support them.
then maybe work the DDR50 or other mode.
> The actual bus clock speed need to be checked in order to prevent/allow boot operation, but not the host capabilities.
Exactly right. :)
As you mentioned, this patch is not perfect. but boot_part_access() called before set to final busmode.
I will consider it, but i think good that don't access at boot partition when mode is hs200/hs400 mode.
>
> As for regular R/W access to boot partition, as far as I see from the JEDEC spec - it can work in HS200 & HS400 modes, so no change is required.
Well, it can work HS200 & HS400 mode at boot partition? i didn't think so.
> Please correct me if I wrong.
Thanks for comments.
Best Regards,
Jaehoon Chung
>
> Thanks,
> Alex
>
>
>
>> -----Original Message-----
>> From: linux-mmc-owner@vger.kernel.org [mailto:linux-mmc-
>> owner@vger.kernel.org] On Behalf Of Jaehoon Chung
>> Sent: Wednesday, August 13, 2014 7:46 AM
>> To: linux-mmc
>> Cc: Chris Ball; Ulf Hansson; Jaehoon Chung
>> Subject: [PATCH] mmc: host: don't access at boot partition when mode is
>> HS200/HS400.
>>
>> HS200/HS400 mode is not supported during boot operation.
>>
>> Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
>> ---
>> include/linux/mmc/host.h | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index
>> 7960424..ce5db96 100644
>> --- a/include/linux/mmc/host.h
>> +++ b/include/linux/mmc/host.h
>> @@ -445,6 +445,10 @@ static inline int mmc_host_cmd23(struct mmc_host
>> *host)
>>
>> static inline int mmc_boot_partition_access(struct mmc_host *host) {
>> + /* HS200 & HS400 mode is not supported during boot operation */
>> + if (host->caps2 & (MMC_CAP2_HS200 | MMC_CAP2_HS400))
>> + return 0;
>> +
>> return !(host->caps2 & MMC_CAP2_BOOTPART_NOACC); }
>>
>> --
>> 1.7.9.5
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the
>> body of a message to majordomo@vger.kernel.org More majordomo info at
>> http://vger.kernel.org/majordomo-info.html
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2014-08-13 13:36 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2014-08-13 4:46 [PATCH] mmc: host: don't access at boot partition when mode is HS200/HS400 Jaehoon Chung
2014-08-13 13:27 ` Alex Lemberg
2014-08-13 13:36 ` Jaehoon Chung
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