2012/5/17, Saugata Das <saugata.das@xxxxxxxxxx>:
> On 17 May 2012 06:35, Namjae Jeon <linkinjeon@xxxxxxxxx> wrote:
>> 2012/5/17, Saugata Das <saugata.das@xxxxxxxxxxxxxx>:
>>> From: Saugata Das <saugata.das@xxxxxxxxxx>
>>>
>>> This patch adds the support for large sector size of 4KB by disabling
>>> emulation.
>>> This patch passes eMMC DATA_SECTOR_SIZE as the logical block size during
>>> mmc_blk_alloc_req.
>>>
>>> In order to use this patch for 4KB sector size, ensure that
>>> USE_NATIVE_SECTOR
>>> is enabled, partition table is 4KB sector size aligned and file system
>>> block
>>> size is 4KB.
>> If you change native 4K from 512B emulation, filesystem sector size is
>> also 4KB align as well block size.
>> because default block size of most of filesystem is 4KB, but
>> filesystem sector size is 512B,
>> So filesystem corruption can be occured on native 4K device.
>>>
>
> I have tested ext4 with 4KB block size and I did not see an instance
> where it requested 512B.
-> yes, you can not see it, because when formating parittion, sector
size is set to 4K by I/O topology. As you know, several filesystems
can be used on eMMC not only Ext4. You should mention filesystem
sector size align in changelog.
> For sure, if someone is using file system with 512B sector on eMMC
> then the USE_NATIVE_SECTOR should not be enabled.
-> it will be the reason about below my question.
>
> The idea behind the patch is, MMC driver should notify the sector size
> information in a generic manner to file system. So, we depend here on
> ext_csd.data_sector_size, which should work in both 512B and 4KB case.
>
>
>>> Signed-off-by: Saugata Das <saugata.das@xxxxxxxxxx>
>>> ---
>>> drivers/mmc/card/block.c | 16 ++++++++++++++--
>>> drivers/mmc/core/mmc.c | 2 ++
>>> 2 files changed, 16 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
>>> index 91cda75..b4d0eb1 100644
>>> --- a/drivers/mmc/card/block.c
>>> +++ b/drivers/mmc/card/block.c
>>> @@ -1284,7 +1284,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue
>>> *mq,
>>> struct request *rqc)
>>> int ret = 1, disable_multi = 0, retry = 0, type;
>>> enum mmc_blk_status status;
>>> struct mmc_queue_req *mq_rq;
>>> - struct request *req;
>>> + struct request *req = rqc;
>>> struct mmc_async_req *areq;
>>>
>>> if (!rqc && !mq->mqrq_prev->req)
>>> @@ -1292,6 +1292,14 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue
>>> *mq,
>>> struct request *rqc)
>>>
>>> do {
>>> if (rqc) {
>>> +
>>> + /*
>>> + * When 4KB native sector is enabled, single
>>> block
>>> + * read or write is not allowed
>>> + */
>>> + if ((brq->data.blocks == 1) &&
>>> + (card->ext_csd.data_sector_size == 4096))
>>> + goto cmd_abort;
>> Why did you add this
>> code in any case ?
>>
>
> This was pointed during the previous review that with 4KB sector mode,
> 512B transfer is not allowed. So, this check has been added here.
-> I think that you should add error log to inform user error case.
>
>>> mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
>>> areq = &mq->mqrq_cur->mmc_active;
>>> } else
>>> @@ -1539,7 +1547,11 @@ static struct mmc_blk_data
>>> *mmc_blk_alloc_req(struct
>>> mmc_card *card,
>>> snprintf(md->disk->disk_name, sizeof(md->disk->disk_name),
>>> "mmcblk%d%s", md->name_idx, subname ? subname : "");
>>>
>>> - blk_queue_logical_block_size(md->queue.queue, 512);
>>> + if (mmc_card_mmc(card))
>>> + blk_queue_logical_block_size(md->queue.queue,
>>> + card->ext_csd.data_sector_size);
>>> + else
>>> + blk_queue_logical_block_size(md->queue.queue, 512);
>>> set_capacity(md->disk, size);
>>>
>>> if (mmc_host_cmd23(card->host)) {
>>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>>> index 7268c26..11444c6 100644
>>> --- a/drivers/mmc/core/mmc.c
>>> +++ b/drivers/mmc/core/mmc.c
>>> @@ -516,6 +516,8 @@ static int mmc_read_ext_csd(struct mmc_card *card,
>>> u8
>>> *ext_csd)
>>> } else {
>>> card->ext_csd.data_tag_unit_size = 0;
>>> }
>>> + } else {
>>> + card->ext_csd.data_sector_size = 512;
>>> }
>>>
>>> out:
>>> --
>>> 1.7.4.3
>>>
>>> --
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>
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