mmc: add erase, secure erase, trim and secure trim operations

SD/MMC cards tend to support an erase operation.  In addition, eMMC v4.4
cards can support secure erase, trim and secure trim operations that are
all variants of the basic erase command.

SD/MMC device attributes "erase_size" and "preferred_erase_size" have been
added.

"erase_size" is the minimum size, in bytes, of an erase operation.  For
MMC, "erase_size" is the erase group size reported by the card.  Note that
"erase_size" does not apply to trim or secure trim operations where the
minimum size is always one 512 byte sector.  For SD, "erase_size" is 512
if the card is block-addressed, 0 otherwise.

SD/MMC cards can erase an arbitrarily large area up to and
including the whole card.  When erasing a large area it may
be desirable to do it in smaller chunks for three reasons:

    1. A single erase command will make all other I/O on the card
       wait.  This is not a problem if the whole card is being erased, but
       erasing one partition will make I/O for another partition on the
       same card wait for the duration of the erase - which could be a
       several minutes.

    2. To be able to inform the user of erase progress.

    3. The erase timeout becomes too large to be very useful.
       Because the erase timeout contains a margin which is multiplied by
       the size of the erase area, the value can end up being several
       minutes for large areas.

"erase_size" is not the most efficient unit to erase (especially for SD
where it is just one sector), hence "preferred_erase_size" provides a good
chunk size for erasing large areas.

For MMC, "preferred_erase_size" is the high-capacity erase size if a card
specifies one, otherwise it is based on the capacity of the card.

For SD, "preferred_erase_size" is the allocation unit size specified by
the card.

"preferred_erase_size" is in bytes.

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Gardiner <bengardiner@nanometrics.ca>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 346 insertions, 0 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 83240faa1dc8..5db49b124ffa 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1050,6 +1050,352 @@ void mmc_detect_change(struct mmc_host *host, unsigned long delay)
 
 EXPORT_SYMBOL(mmc_detect_change);
 
+void mmc_init_erase(struct mmc_card *card)
+{
+        unsigned int sz;
+
+        if (is_power_of_2(card->erase_size))
+                card->erase_shift = ffs(card->erase_size) - 1;
+        else
+                card->erase_shift = 0;
+
+        /*
+         * It is possible to erase an arbitrarily large area of an SD or MMC
+         * card.  That is not desirable because it can take a long time
+         * (minutes) potentially delaying more important I/O, and also the
+         * timeout calculations become increasingly hugely over-estimated.
+         * Consequently, 'pref_erase' is defined as a guide to limit erases
+         * to that size and alignment.
+         *
+         * For SD cards that define Allocation Unit size, limit erases to one
+         * Allocation Unit at a time.  For MMC cards that define High Capacity
+         * Erase Size, whether it is switched on or not, limit to that size.
+         * Otherwise just have a stab at a good value.  For modern cards it
+         * will end up being 4MiB.  Note that if the value is too small, it
+         * can end up taking longer to erase.
+         */
+        if (mmc_card_sd(card) && card->ssr.au) {
+                card->pref_erase = card->ssr.au;
+                card->erase_shift = ffs(card->ssr.au) - 1;
+        } else if (card->ext_csd.hc_erase_size) {
+                card->pref_erase = card->ext_csd.hc_erase_size;
+        } else {
+                sz = (card->csd.capacity << (card->csd.read_blkbits - 9)) >> 11;
+                if (sz < 128)
+                        card->pref_erase = 512 * 1024 / 512;
+                else if (sz < 512)
+                        card->pref_erase = 1024 * 1024 / 512;
+                else if (sz < 1024)
+                        card->pref_erase = 2 * 1024 * 1024 / 512;
+                else
+                        card->pref_erase = 4 * 1024 * 1024 / 512;
+                if (card->pref_erase < card->erase_size)
+                        card->pref_erase = card->erase_size;
+                else {
+                        sz = card->pref_erase % card->erase_size;
+                        if (sz)
+                                card->pref_erase += card->erase_size - sz;
+                }
+        }
+}
+
+static void mmc_set_mmc_erase_timeout(struct mmc_card *card,
+                                      struct mmc_command *cmd,
+                                      unsigned int arg, unsigned int qty)
+{
+        unsigned int erase_timeout;
+
+        if (card->ext_csd.erase_group_def & 1) {
+                /* High Capacity Erase Group Size uses HC timeouts */
+                if (arg == MMC_TRIM_ARG)
+                        erase_timeout = card->ext_csd.trim_timeout;
+                else
+                        erase_timeout = card->ext_csd.hc_erase_timeout;
+        } else {
+                /* CSD Erase Group Size uses write timeout */
+                unsigned int mult = (10 << card->csd.r2w_factor);
+                unsigned int timeout_clks = card->csd.tacc_clks * mult;
+                unsigned int timeout_us;
+
+                /* Avoid overflow: e.g. tacc_ns=80000000 mult=1280 */
+                if (card->csd.tacc_ns < 1000000)
+                        timeout_us = (card->csd.tacc_ns * mult) / 1000;
+                else
+                        timeout_us = (card->csd.tacc_ns / 1000) * mult;
+
+                /*
+                 * ios.clock is only a target.  The real clock rate might be
+                 * less but not that much less, so fudge it by multiplying by 2.
+                 */
+                timeout_clks <<= 1;
+                timeout_us += (timeout_clks * 1000) /
+                              (card->host->ios.clock / 1000);
+
+                erase_timeout = timeout_us / 1000;
+
+                /*
+                 * Theoretically, the calculation could underflow so round up
+                 * to 1ms in that case.
+                 */
+                if (!erase_timeout)
+                        erase_timeout = 1;
+        }
+
+        /* Multiplier for secure operations */
+        if (arg & MMC_SECURE_ARGS) {
+                if (arg == MMC_SECURE_ERASE_ARG)
+                        erase_timeout *= card->ext_csd.sec_erase_mult;
+                else
+                        erase_timeout *= card->ext_csd.sec_trim_mult;
+        }
+
+        erase_timeout *= qty;
+
+        /*
+         * Ensure at least a 1 second timeout for SPI as per
+         * 'mmc_set_data_timeout()'
+         */
+        if (mmc_host_is_spi(card->host) && erase_timeout < 1000)
+                erase_timeout = 1000;
+
+        cmd->erase_timeout = erase_timeout;
+}
+
+static void mmc_set_sd_erase_timeout(struct mmc_card *card,
+                                     struct mmc_command *cmd, unsigned int arg,
+                                     unsigned int qty)
+{
+        if (card->ssr.erase_timeout) {
+                /* Erase timeout specified in SD Status Register (SSR) */
+                cmd->erase_timeout = card->ssr.erase_timeout * qty +
+                                     card->ssr.erase_offset;
+        } else {
+                /*
+                 * Erase timeout not specified in SD Status Register (SSR) so
+                 * use 250ms per write block.
+                 */
+                cmd->erase_timeout = 250 * qty;
+        }
+
+        /* Must not be less than 1 second */
+        if (cmd->erase_timeout < 1000)
+                cmd->erase_timeout = 1000;
+}
+
+static void mmc_set_erase_timeout(struct mmc_card *card,
+                                  struct mmc_command *cmd, unsigned int arg,
+                                  unsigned int qty)
+{
+        if (mmc_card_sd(card))
+                mmc_set_sd_erase_timeout(card, cmd, arg, qty);
+        else
+                mmc_set_mmc_erase_timeout(card, cmd, arg, qty);
+}
+
+static int mmc_do_erase(struct mmc_card *card, unsigned int from,
+                        unsigned int to, unsigned int arg)
+{
+        struct mmc_command cmd;
+        unsigned int qty = 0;
+        int err;
+
+        /*
+         * qty is used to calculate the erase timeout which depends on how many
+         * erase groups (or allocation units in SD terminology) are affected.
+         * We count erasing part of an erase group as one erase group.
+         * For SD, the allocation units are always a power of 2.  For MMC, the
+         * erase group size is almost certainly also power of 2, but it does not
+         * seem to insist on that in the JEDEC standard, so we fall back to
+         * division in that case.  SD may not specify an allocation unit size,
+         * in which case the timeout is based on the number of write blocks.
+         *
+         * Note that the timeout for secure trim 2 will only be correct if the
+         * number of erase groups specified is the same as the total of all
+         * preceding secure trim 1 commands.  Since the power may have been
+         * lost since the secure trim 1 commands occurred, it is generally
+         * impossible to calculate the secure trim 2 timeout correctly.
+         */
+        if (card->erase_shift)
+                qty += ((to >> card->erase_shift) -
+                        (from >> card->erase_shift)) + 1;
+        else if (mmc_card_sd(card))
+                qty += to - from + 1;
+        else
+                qty += ((to / card->erase_size) -
+                        (from / card->erase_size)) + 1;
+
+        if (!mmc_card_blockaddr(card)) {
+                from <<= 9;
+                to <<= 9;
+        }
+
+        memset(&cmd, 0, sizeof(struct mmc_command));
+        if (mmc_card_sd(card))
+                cmd.opcode = SD_ERASE_WR_BLK_START;
+        else
+                cmd.opcode = MMC_ERASE_GROUP_START;
+        cmd.arg = from;
+        cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
+        err = mmc_wait_for_cmd(card->host, &cmd, 0);
+        if (err) {
+                printk(KERN_ERR "mmc_erase: group start error %d, "
+                       "status %#x\n", err, cmd.resp[0]);
+                err = -EINVAL;
+                goto out;
+        }
+
+        memset(&cmd, 0, sizeof(struct mmc_command));
+        if (mmc_card_sd(card))
+                cmd.opcode = SD_ERASE_WR_BLK_END;
+        else
+                cmd.opcode = MMC_ERASE_GROUP_END;
+        cmd.arg = to;
+        cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
+        err = mmc_wait_for_cmd(card->host, &cmd, 0);
+        if (err) {
+                printk(KERN_ERR "mmc_erase: group end error %d, status %#x\n",
+                       err, cmd.resp[0]);
+                err = -EINVAL;
+                goto out;
+        }
+
+        memset(&cmd, 0, sizeof(struct mmc_command));
+        cmd.opcode = MMC_ERASE;
+        cmd.arg = arg;
+        cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
+        mmc_set_erase_timeout(card, &cmd, arg, qty);
+        err = mmc_wait_for_cmd(card->host, &cmd, 0);
+        if (err) {
+                printk(KERN_ERR "mmc_erase: erase error %d, status %#x\n",
+                       err, cmd.resp[0]);
+                err = -EIO;
+                goto out;
+        }
+
+        if (mmc_host_is_spi(card->host))
+                goto out;
+
+        do {
+                memset(&cmd, 0, sizeof(struct mmc_command));
+                cmd.opcode = MMC_SEND_STATUS;
+                cmd.arg = card->rca << 16;
+                cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
+                /* Do not retry else we can't see errors */
+                err = mmc_wait_for_cmd(card->host, &cmd, 0);
+                if (err || (cmd.resp[0] & 0xFDF92000)) {
+                        printk(KERN_ERR "error %d requesting status %#x\n",
+                                err, cmd.resp[0]);
+                        err = -EIO;
+                        goto out;
+                }
+        } while (!(cmd.resp[0] & R1_READY_FOR_DATA) ||
+                 R1_CURRENT_STATE(cmd.resp[0]) == 7);
+out:
+        return err;
+}
+
+/**
+ * mmc_erase - erase sectors.
+ * @card: card to erase
+ * @from: first sector to erase
+ * @nr: number of sectors to erase
+ * @arg: erase command argument (SD supports only %MMC_ERASE_ARG)
+ *
+ * Caller must claim host before calling this function.
+ */
+int mmc_erase(struct mmc_card *card, unsigned int from, unsigned int nr,
+              unsigned int arg)
+{
+        unsigned int rem, to = from + nr;
+
+        if (!(card->host->caps & MMC_CAP_ERASE) ||
+            !(card->csd.cmdclass & CCC_ERASE))
+                return -EOPNOTSUPP;
+
+        if (!card->erase_size)
+                return -EOPNOTSUPP;
+
+        if (mmc_card_sd(card) && arg != MMC_ERASE_ARG)
+                return -EOPNOTSUPP;
+
+        if ((arg & MMC_SECURE_ARGS) &&
+            !(card->ext_csd.sec_feature_support & EXT_CSD_SEC_ER_EN))
+                return -EOPNOTSUPP;
+
+        if ((arg & MMC_TRIM_ARGS) &&
+            !(card->ext_csd.sec_feature_support & EXT_CSD_SEC_GB_CL_EN))
+                return -EOPNOTSUPP;
+
+        if (arg == MMC_SECURE_ERASE_ARG) {
+                if (from % card->erase_size || nr % card->erase_size)
+                        return -EINVAL;
+        }
+
+        if (arg == MMC_ERASE_ARG) {
+                rem = from % card->erase_size;
+                if (rem) {
+                        rem = card->erase_size - rem;
+                        from += rem;
+                        if (nr > rem)
+                                nr -= rem;
+                        else
+                                return 0;
+                }
+                rem = nr % card->erase_size;
+                if (rem)
+                        nr -= rem;
+        }
+
+        if (nr == 0)
+                return 0;
+
+        to = from + nr;
+
+        if (to <= from)
+                return -EINVAL;
+
+        /* 'from' and 'to' are inclusive */
+        to -= 1;
+
+        return mmc_do_erase(card, from, to, arg);
+}
+EXPORT_SYMBOL(mmc_erase);
+
+int mmc_can_erase(struct mmc_card *card)
+{
+        if ((card->host->caps & MMC_CAP_ERASE) &&
+            (card->csd.cmdclass & CCC_ERASE) && card->erase_size)
+                return 1;
+        return 0;
+}
+EXPORT_SYMBOL(mmc_can_erase);
+
+int mmc_can_trim(struct mmc_card *card)
+{
+        if (card->ext_csd.sec_feature_support & EXT_CSD_SEC_GB_CL_EN)
+                return 1;
+        return 0;
+}
+EXPORT_SYMBOL(mmc_can_trim);
+
+int mmc_can_secure_erase_trim(struct mmc_card *card)
+{
+        if (card->ext_csd.sec_feature_support & EXT_CSD_SEC_ER_EN)
+                return 1;
+        return 0;
+}
+EXPORT_SYMBOL(mmc_can_secure_erase_trim);
+
+int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,
+                            unsigned int nr)
+{
+        if (!card->erase_size)
+                return 0;
+        if (from % card->erase_size || nr % card->erase_size)
+                return 0;
+        return 1;
+}
+EXPORT_SYMBOL(mmc_erase_group_aligned);
 
 void mmc_rescan(struct work_struct *work)
 {