On 02/03/2012 01:08 AM, S, Venkatraman wrote:
> On Wed, Feb 1, 2012 at 8:57 PM, Saugata Das <saugata.das@xxxxxxxxxxxxxx> wrote:
>> From: Saugata Das <saugata.das@xxxxxxxxxx>
>>
>> This patch groups the read or write transfers to eMMC in different contexts
>> based on the block number. Transfers to consecutive blocks are grouped to a
>> common context. So several small transfers combine to give performance like
>> a large multi block transfer.
>>
>> The patch creates a context of 1MB multiple in non-large unit mode. Reliable
>> mode is enabled in the context based on whether reliable write is enabled.
>>
>> Signed-off-by: Saugata Das <saugata.das@xxxxxxxxxx>
>> ---
> The patch subject could be better off as "mmc: eMMC4.5 context ID support"
>
>> drivers/mmc/card/block.c | 263 ++++++++++++++++++++++++++++++++++++++++++----
>> drivers/mmc/core/mmc.c | 6 +
>> include/linux/mmc/card.h | 13 +++
>> include/linux/mmc/core.h | 9 ++
>> include/linux/mmc/host.h | 1 +
>> include/linux/mmc/mmc.h | 3 +
>> 6 files changed, 275 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
>> index 176b78e..161174a 100644
>> --- a/drivers/mmc/card/block.c
>> +++ b/drivers/mmc/card/block.c
>> @@ -127,6 +127,8 @@ enum mmc_blk_status {
>> module_param(perdev_minors, int, 0444);
>> MODULE_PARM_DESC(perdev_minors, "Minors numbers to allocate per device");
>>
>> +static int mmc_blk_issue_rw_rq(struct mmc_queue *, struct request *);
>> +
>> static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk)
>> {
>> struct mmc_blk_data *md;
>> @@ -1071,6 +1073,192 @@ static int mmc_blk_err_check(struct mmc_card *card,
>> return MMC_BLK_SUCCESS;
>> }
>>
>> +/*
>> + * Update the context information in the ext. CSD
>
> Mixed case
>
>> + */
>> +static int mmc_context_modify(struct mmc_queue *mq,
>> + struct mmc_card *card,
>> + unsigned int context_id,
>> + unsigned char context_conf)
>> +{
>> + /*
>> + * Wait for any ongoing transfer
>> + */
>> + if (card->host->areq)
>> + mmc_blk_issue_rw_rq(mq, NULL);
>> +
>> + /*
>> + * CONTEXT_CONF array starts from context id 1
>> + */
>> + return mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
>> + EXT_CSD_CONTEXT_CONF + context_id - 1,
>> + context_conf,
>> + card->ext_csd.generic_cmd6_time);
>> +}
>> +
>> +/*
>> + * Update timestamp, size and close context if needed
>> + */
>> +static int mmc_check_close_context(struct mmc_queue *mq,
>> + struct mmc_card *card,
>> + unsigned int context_id,
>> + unsigned int status)
>> +{
>> + /*
>> + * Check only for valid contexts
>> + */
>> + if ((context_id > 0) &&
>> + (context_id <= card->ext_csd.max_context_id) &&
>> + (card->mmc_context[context_id].valid)) {
>> +
>> + /*
>> + * Incase of an error or we are multiple of erase block then
>> + * close the context
>> + */
>> + if ((status) ||
>> + ((card->mmc_context[context_id].size %
>> + card->ext_csd.lu_size) == 0)) {
>> + if (mmc_context_modify(mq, card, context_id,
>> + MMC_CONTEXT_CLOSE))
>> + return -1;
> Should propagate the error code instead of returning -1
>
>> + card->mmc_context[context_id].valid = 0;
>> + }
>> + return 0;
>> + }
>> + return 0;
>> +}
>> +
>> +/*
>> + * Update timestamp, size and close context if needed
>> + */
>> +static int mmc_force_close_all_write_context(struct mmc_queue *mq,
>> + struct mmc_card *card)
>> +{
>> + int i, ret = 0;
>> + for (i = 1; i <= card->ext_csd.max_context_id; i++) {
>> + if (card->mmc_context[i].direction != MMC_CONTEXT_READ) {
>> + ret = mmc_check_close_context(mq, card, i,
>> + MMC_CONTEXT_FORCE_CLOSE);
>> + if (ret)
>> + return ret;
>> + }
>> + }
>> + return ret;
>> +}
>> +
>> +/*
>> + * Search for a context which is in the same direction and
>> + * continuous in block numbers. If no matching context is
>> + * found then take up an unused context. If all contexts are
>> + * used then close the context which is least recently used,
>> + * close it and the use it for the new transfer
>> + */
>> +static int mmc_get_context_id(struct mmc_queue *mq,
>> + struct mmc_card *card,
>> + unsigned int offset,
>> + unsigned int size,
>> + unsigned int direction,
>> + unsigned int rel_wr)
>> +{
>> + int i, free_index = -1, lru_index = -1, ret_index;
>> + unsigned int old_timestamp = -1;
>> + unsigned int reliability_mode = rel_wr ? (0x01<<5) : 0;
>> + struct mmc_context *context_ptr = &card->mmc_context[1];
>> +
>> + /*
>> + * For older than 4.5 eMMC, there is no context ID
>> + */
>> + if (card->ext_csd.max_context_id == 0)
>> + return 0;
>> +
>> + if (card->host->caps2 & MMC_CAP2_NO_CONTEXT)
>> + return 0;
>> +
>> + /*
>> + * If the request is LU size multiple then avoid
>> + * using any context
>> + */
>> + if ((size % card->ext_csd.lu_size) == 0)
>> + return 0;
>> +
>> + /*
>> + * Context 0 is unused
>> + */
>> + for (i = 1; i <= card->ext_csd.max_context_id; i++, context_ptr++) {
>> +
>> + unsigned int context_start_blk;
>> +
>> + if (!context_ptr->valid) {
>> + if (free_index == -1)
>> + free_index = i;
>> + continue;
>> + }
>> +
>> + context_start_blk = context_ptr->offset -
>> + context_ptr->size;
>> +
>> + if ((context_start_blk <= offset) &&
>> + (context_ptr->offset > offset)) {
>
> How would this condition ever match ? The starting offset of the
> previous request is usually less than the current request or it is
> more, but not both.
>
>> + int ret = mmc_check_close_context(mq, card, i,
>> + MMC_CONTEXT_FORCE_CLOSE);
>> + if (ret < 0)
>> + return ret;
>> + if (free_index == -1)
>> + free_index = i;
>> + break;
>> + }
>> +
>> + if ((lru_index == -1) ||
>> + (context_ptr->timestamp < old_timestamp)) {
>> + old_timestamp = context_ptr->timestamp;
>> + lru_index = i;
>> + }
>> +
>> + if ((context_ptr->direction != direction) ||
>> + (context_ptr->offset != offset) ||
>> + (context_ptr->reliability_mode !=
>> + reliability_mode))
>> + continue;
>
> I think the reliability mode match shouldn't matter. If the writes to
> the same section of the device, the best of the reliability modes can
> be applied.
> This section should be moved above the context_start_blk and offset
> checking code.
> Why close an ongoing context if the directions don't match eventually ?
>
>> +
>> + context_ptr->timestamp = jiffies;
>> + context_ptr->offset += size;
>> + context_ptr->size += size;
>> + return i;
>> + }
>> +
>> + if (free_index != -1) {
>> + /*
>> + * Open a free context
>> + */
>> + if (mmc_context_modify(mq, card, free_index,
>> + (direction & 0x03) | reliability_mode))
>> + return -1;
>> + ret_index = free_index;
>> + } else if (lru_index != -1) {
>> + /*
>> + * Close and reopen the LRU context
>> + */
>> + if (mmc_context_modify(mq, card, lru_index, MMC_CONTEXT_CLOSE))
>> + return -1;
>> +
>> + if (mmc_context_modify(mq, card, lru_index,
>> + (direction & 0x03) | reliability_mode))
>> + return -1;
>> + ret_index = lru_index;
>> + } else
>> + return -1;
>> +
>> + context_ptr = &card->mmc_context[ret_index];
>> + context_ptr->offset = offset+size;
>> + context_ptr->size = size;
>> + context_ptr->direction = direction;
>> + context_ptr->timestamp = jiffies;
>> + context_ptr->reliability_mode = reliability_mode;
>> + context_ptr->valid = 1;
>> +
>> + return ret_index;
>> +}
>> +
>> static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
>> struct mmc_card *card,
>> int disable_multi,
>> @@ -1080,7 +1268,6 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
>> struct mmc_blk_request *brq = &mqrq->brq;
>> struct request *req = mqrq->req;
>> struct mmc_blk_data *md = mq->data;
>> - bool do_data_tag;
>>
>> /*
>> * Reliable writes are used to implement Forced Unit Access and
>> @@ -1157,16 +1344,6 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
>> mmc_apply_rel_rw(brq, card, req);
>>
>> /*
>> - * Data tag is used only during writing meta data to speed
>> - * up write and any subsequent read of this meta data
>> - */
>> - do_data_tag = (card->ext_csd.data_tag_unit_size) &&
>> - (req->cmd_flags & REQ_META) &&
>> - (rq_data_dir(req) == WRITE) &&
>> - ((brq->data.blocks * brq->data.blksz) >=
>> - card->ext_csd.data_tag_unit_size);
>> -
>> - /*
>> * Pre-defined multi-block transfers are preferable to
>> * open ended-ones (and necessary for reliable writes).
>> * However, it is not sufficient to just send CMD23,
>> @@ -1184,15 +1361,54 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
>> * We'll avoid using CMD23-bounded multiblock writes for
>> * these, while retaining features like reliable writes.
>> */
>> - if ((md->flags & MMC_BLK_CMD23) && mmc_op_multi(brq->cmd.opcode) &&
>> - (do_rel_wr || !(card->quirks & MMC_QUIRK_BLK_NO_CMD23) ||
>> - do_data_tag)) {
>> - brq->sbc.opcode = MMC_SET_BLOCK_COUNT;
>> - brq->sbc.arg = brq->data.blocks |
>> - (do_rel_wr ? (1 << 31) : 0) |
>> - (do_data_tag ? (1 << 29) : 0);
>> - brq->sbc.flags = MMC_RSP_R1 | MMC_CMD_AC;
>> - brq->mrq.sbc = &brq->sbc;
>> + if ((md->flags & MMC_BLK_CMD23) && mmc_op_multi(brq->cmd.opcode)) {
>> + /*
>> + * Context ID is used for non-large unit and non-reliable
>> + * write transfers provided the start block number
>> + * sequentially follows any of the open contexts
>> + */
>> + int context_id;
>> +
>> + /*
>> + * Data tag is used only during writing meta data to speed
>> + * up write and any subsequent read of this meta data
>> + */
>> + bool do_data_tag = (card->ext_csd.data_tag_unit_size) &&
>> + (req->cmd_flags & REQ_META) &&
>> + (rq_data_dir(req) == WRITE) &&
>> + ((brq->data.blocks * brq->data.blksz) >=
>> + card->ext_csd.data_tag_unit_size);
>> +
>> + /*
>> + * During fsync, ensure that data is committed to storage
>> + */
>> + if (req->cmd_flags & (REQ_FLUSH | REQ_SYNC))
>> + mmc_force_close_all_write_context(mq, card);
>> +
>> + /*
>> + * Context ID is used for non-large unit and non-reliable
>> + * write transfers provided the start block number
>> + * sequentially follows any of the open contexts
>> + */
>> + context_id = mmc_get_context_id(mq,
>> + card,
>> + blk_rq_pos(req),
>> + brq->data.blocks,
>> + (rq_data_dir(req) == WRITE) ? MMC_CONTEXT_WRITE :
>> + MMC_CONTEXT_READ,
>> + do_rel_wr);
>> +
>> + if (do_rel_wr || !(card->quirks & MMC_QUIRK_BLK_NO_CMD23) ||
>> + do_data_tag || (context_id > 0)) {
>> + brq->sbc.opcode = MMC_SET_BLOCK_COUNT;
>> + brq->sbc.arg = brq->data.blocks |
>> + (do_rel_wr ? (1 << 31) : 0) |
>> + (do_data_tag ? (1 << 29) : 0) |
>> + (((context_id > 0) && (!do_rel_wr)) ?
>> + ((context_id & 0x0f) << 25) : 0);
>> + brq->sbc.flags = MMC_RSP_R1 | MMC_CMD_AC;
>> + brq->mrq.sbc = &brq->sbc;
>> + }
Can Data-tag & context-Id use together?
Best Regards,
Jaehoon Chung
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