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.
For sure, if someone is using file system with 512B sector on eMMC
then the USE_NATIVE_SECTOR should not be enabled.
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.
>> 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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