From e056a1b5b67b4e4bfad00bf143ab14f634777705 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Tue, 28 Jun 2011 17:16:02 +0300 Subject: [PATCH] mmc: queue: let host controllers specify maximum discard timeout Some host controllers will not operate without a hardware timeout that is limited in value. However large discards require large timeouts, so there needs to be a way to specify the maximum discard size. A host controller driver may now specify the maximum discard timeout possible so that max_discard_sectors can be calculated. However, for eMMC when the High Capacity Erase Group Size is not in use, the timeout calculation depends on clock rate which may change. For that case Preferred Erase Size is used instead. Signed-off-by: Adrian Hunter Signed-off-by: Chris Ball --- drivers/mmc/card/queue.c | 33 +++++++++++------ drivers/mmc/core/core.c | 76 ++++++++++++++++++++++++++++++++++++++++ include/linux/mmc/core.h | 1 + include/linux/mmc/host.h | 1 + 4 files changed, 101 insertions(+), 10 deletions(-) diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c index 6413afa318d2..defc11b4572c 100644 --- a/drivers/mmc/card/queue.c +++ b/drivers/mmc/card/queue.c @@ -101,6 +101,27 @@ static void mmc_request(struct request_queue *q) wake_up_process(mq->thread); } +static void mmc_queue_setup_discard(struct request_queue *q, + struct mmc_card *card) +{ + unsigned max_discard; + + max_discard = mmc_calc_max_discard(card); + if (!max_discard) + return; + + queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q); + q->limits.max_discard_sectors = max_discard; + if (card->erased_byte == 0) + q->limits.discard_zeroes_data = 1; + q->limits.discard_granularity = card->pref_erase << 9; + /* granularity must not be greater than max. discard */ + if (card->pref_erase > max_discard) + q->limits.discard_granularity = 0; + if (mmc_can_secure_erase_trim(card)) + queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, q); +} + /** * mmc_init_queue - initialise a queue structure. * @mq: mmc queue @@ -130,16 +151,8 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, blk_queue_prep_rq(mq->queue, mmc_prep_request); queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue); - if (mmc_can_erase(card)) { - queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mq->queue); - mq->queue->limits.max_discard_sectors = UINT_MAX; - if (card->erased_byte == 0) - mq->queue->limits.discard_zeroes_data = 1; - mq->queue->limits.discard_granularity = card->pref_erase << 9; - if (mmc_can_secure_erase_trim(card)) - queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, - mq->queue); - } + if (mmc_can_erase(card)) + mmc_queue_setup_discard(mq->queue, card); #ifdef CONFIG_MMC_BLOCK_BOUNCE if (host->max_segs == 1) { diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 7843efe22359..ac82865b8c2f 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -1516,6 +1516,82 @@ int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from, } EXPORT_SYMBOL(mmc_erase_group_aligned); +static unsigned int mmc_do_calc_max_discard(struct mmc_card *card, + unsigned int arg) +{ + struct mmc_host *host = card->host; + unsigned int max_discard, x, y, qty = 0, max_qty, timeout; + unsigned int last_timeout = 0; + + if (card->erase_shift) + max_qty = UINT_MAX >> card->erase_shift; + else if (mmc_card_sd(card)) + max_qty = UINT_MAX; + else + max_qty = UINT_MAX / card->erase_size; + + /* Find the largest qty with an OK timeout */ + do { + y = 0; + for (x = 1; x && x <= max_qty && max_qty - x >= qty; x <<= 1) { + timeout = mmc_erase_timeout(card, arg, qty + x); + if (timeout > host->max_discard_to) + break; + if (timeout < last_timeout) + break; + last_timeout = timeout; + y = x; + } + qty += y; + } while (y); + + if (!qty) + return 0; + + if (qty == 1) + return 1; + + /* Convert qty to sectors */ + if (card->erase_shift) + max_discard = --qty << card->erase_shift; + else if (mmc_card_sd(card)) + max_discard = qty; + else + max_discard = --qty * card->erase_size; + + return max_discard; +} + +unsigned int mmc_calc_max_discard(struct mmc_card *card) +{ + struct mmc_host *host = card->host; + unsigned int max_discard, max_trim; + + if (!host->max_discard_to) + return UINT_MAX; + + /* + * Without erase_group_def set, MMC erase timeout depends on clock + * frequence which can change. In that case, the best choice is + * just the preferred erase size. + */ + if (mmc_card_mmc(card) && !(card->ext_csd.erase_group_def & 1)) + return card->pref_erase; + + max_discard = mmc_do_calc_max_discard(card, MMC_ERASE_ARG); + if (mmc_can_trim(card)) { + max_trim = mmc_do_calc_max_discard(card, MMC_TRIM_ARG); + if (max_trim < max_discard) + max_discard = max_trim; + } else if (max_discard < card->erase_size) { + max_discard = 0; + } + pr_debug("%s: calculated max. discard sectors %u for timeout %u ms\n", + mmc_hostname(host), max_discard, host->max_discard_to); + return max_discard; +} +EXPORT_SYMBOL(mmc_calc_max_discard); + int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen) { struct mmc_command cmd = {0}; diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h index 791f060a6f1d..86d81cf75b70 100644 --- a/include/linux/mmc/core.h +++ b/include/linux/mmc/core.h @@ -155,6 +155,7 @@ extern int mmc_can_trim(struct mmc_card *card); extern int mmc_can_secure_erase_trim(struct mmc_card *card); extern int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from, unsigned int nr); +extern unsigned int mmc_calc_max_discard(struct mmc_card *card); extern int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen); diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index fc24b38b48cb..c67d19b5542a 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -231,6 +231,7 @@ struct mmc_host { unsigned int max_req_size; /* maximum number of bytes in one req */ unsigned int max_blk_size; /* maximum size of one mmc block */ unsigned int max_blk_count; /* maximum number of blocks in one req */ + unsigned int max_discard_to; /* max. discard timeout in ms */ /* private data */ spinlock_t lock; /* lock for claim and bus ops */ -- 2.39.2