The patch titled
mmc: Add support for SDHC cards
has been added to the -mm tree. Its filename is
mmc-add-support-for-sdhc-cards.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: mmc: Add support for SDHC cards
From: Philip Langdale <philipl@xxxxxxxxx>
Thanks to the generous donation of an SDHC card by John Gilmore, and the
surprisingly enlightened decision by the SD Card Association to publish
useful specs, I've been able to bash out support for SDHC. The changes are
not too profound:
i) Add a card flag indicating the card uses block level addressing and
check it in the block driver. As we never took advantage of byte-level
addressing, this simply involves skipping the block -> byte translation
when sending commands.
ii) The layout of the CSD is changed - a set of fields are discarded to
make space for a larger C_SIZE. We did not reference any of the
discarded fields except those related to the C_SIZE.
iii) Read and write timeouts are fixed values and not calculated from
CSD values.
iv) Before invoking SEND_APP_OP_COND, we must invoke the new
SEND_IF_COND to inform the card we support SDHC.
I've done some basic read and write tests and everything seems to work fine
but one should obviously use caution in case it eats your data.
Addendum: Similar spec changes were introduced by the MMC Association in
version 4.2 to switch to block addressing. We do not have access to the
4.2 spec or even a change summary as we did for 3 -> 4. My guess as to
what's changed looks something like the following:
i) A new field is added to the ext_csd to store the capacity that cannot
be described using existing csd fields.
ii) A new field is added to the ext_csd to indicate the need for block
addressing.
iii) A new write-only field is added to the ext_csd which has to be
toggled to tell the card that the host supports block-addressing. But
perhaps compatibility requires that a new command be used like for
SDHC...
If someone has access to the spec and can shed some light on the subject in
a legal way, please let us know. Of course, I don't think there are any
MMC HC cards on the market yet, but one was announced last month.
Signed-off-by: Philipl Langdale <philipl@xxxxxxxxx>
Cc: Pierre Ossman <drzeus@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/mmc/mmc.c | 40 ++++++++++++++++++++++++++++-----
drivers/mmc/mmc_block.c | 4 ++-
include/linux/mmc/card.h | 3 ++
include/linux/mmc/mmc.h | 1
include/linux/mmc/protocol.h | 13 +++++++++-
5 files changed, 54 insertions(+), 7 deletions(-)
diff -puN drivers/mmc/mmc_block.c~mmc-add-support-for-sdhc-cards drivers/mmc/mmc_block.c
--- a/drivers/mmc/mmc_block.c~mmc-add-support-for-sdhc-cards
+++ a/drivers/mmc/mmc_block.c
@@ -237,7 +237,9 @@ static int mmc_blk_issue_rq(struct mmc_q
brq.mrq.cmd = &brq.cmd;
brq.mrq.data = &brq.data;
- brq.cmd.arg = req->sector << 9;
+ brq.cmd.arg = req->sector;
+ if (!mmc_card_blockaddr(card))
+ brq.cmd.arg <<= 9;
brq.cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
brq.data.blksz = 1 << md->block_bits;
brq.stop.opcode = MMC_STOP_TRANSMISSION;
diff -puN drivers/mmc/mmc.c~mmc-add-support-for-sdhc-cards drivers/mmc/mmc.c
--- a/drivers/mmc/mmc.c~mmc-add-support-for-sdhc-cards
+++ a/drivers/mmc/mmc.c
@@ -294,7 +294,10 @@ void mmc_set_data_timeout(struct mmc_dat
else
limit_us = 100000;
- if (timeout_us > limit_us) {
+ /*
+ * SDHC cards always use these fixed values.
+ */
+ if (timeout_us > limit_us || mmc_card_blockaddr(card)) {
data->timeout_ns = limit_us * 1000;
data->timeout_clks = 0;
}
@@ -593,12 +596,15 @@ static void mmc_decode_csd(struct mmc_ca
if (mmc_card_sd(card)) {
csd_struct = UNSTUFF_BITS(resp, 126, 2);
- if (csd_struct != 0) {
+ if (csd_struct != 0 && csd_struct != 1) {
printk("%s: unrecognised CSD structure version %d\n",
mmc_hostname(card->host), csd_struct);
mmc_card_set_bad(card);
return;
}
+ if (csd_struct == 1) {
+ mmc_card_set_blockaddr(card);
+ }
m = UNSTUFF_BITS(resp, 115, 4);
e = UNSTUFF_BITS(resp, 112, 3);
@@ -610,9 +616,14 @@ static void mmc_decode_csd(struct mmc_ca
csd->max_dtr = tran_exp[e] * tran_mant[m];
csd->cmdclass = UNSTUFF_BITS(resp, 84, 12);
- e = UNSTUFF_BITS(resp, 47, 3);
- m = UNSTUFF_BITS(resp, 62, 12);
- csd->capacity = (1 + m) << (e + 2);
+ if (csd_struct == 0) {
+ e = UNSTUFF_BITS(resp, 47, 3);
+ m = UNSTUFF_BITS(resp, 62, 12);
+ csd->capacity = (1 + m) << (e + 2);
+ } else if (csd_struct == 1) {
+ m = UNSTUFF_BITS(resp, 48, 22);
+ csd->capacity = (1 + m) << 10;
+ }
csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
@@ -829,6 +840,25 @@ static int mmc_send_app_op_cond(struct m
{
struct mmc_command cmd;
int i, err = 0;
+ static const u8 test_pattern = 0xAA;
+
+ /*
+ * To support SD 2.0 cards, we must always invoke SD_SEND_IF_COND
+ * before SD_APP_OP_COND. This command will harmlessly fail for
+ * SD 1.0 and MMC cards (fortunately including MMC 4 cards).
+ */
+ cmd.opcode = SD_SEND_IF_COND;
+ cmd.arg = ((host->ocr_avail & 0xFF8000) != 0) << 8 | test_pattern;
+ cmd.flags = MMC_RSP_R7 | MMC_CMD_BCR;
+
+ err = mmc_wait_for_cmd(host, &cmd, 0);
+ if (err == MMC_ERR_NONE) {
+ if ((cmd.resp[0] & 0xFF) != test_pattern) {
+ return MMC_ERR_FAILED;
+ } else if (ocr != 0) {
+ ocr |= 1 << 30;
+ }
+ }
cmd.opcode = SD_APP_OP_COND;
cmd.arg = ocr;
diff -puN include/linux/mmc/card.h~mmc-add-support-for-sdhc-cards include/linux/mmc/card.h
--- a/include/linux/mmc/card.h~mmc-add-support-for-sdhc-cards
+++ a/include/linux/mmc/card.h
@@ -71,6 +71,7 @@ struct mmc_card {
#define MMC_STATE_SDCARD (1<<3) /* is an SD card */
#define MMC_STATE_READONLY (1<<4) /* card is read-only */
#define MMC_STATE_HIGHSPEED (1<<5) /* card is in high speed mode */
+#define MMC_STATE_BLOCKADDR (1<<6) /* card uses block-addressing */
u32 raw_cid[4]; /* raw card CID */
u32 raw_csd[4]; /* raw card CSD */
u32 raw_scr[2]; /* raw card SCR */
@@ -87,6 +88,7 @@ struct mmc_card {
#define mmc_card_sd(c) ((c)->state & MMC_STATE_SDCARD)
#define mmc_card_readonly(c) ((c)->state & MMC_STATE_READONLY)
#define mmc_card_highspeed(c) ((c)->state & MMC_STATE_HIGHSPEED)
+#define mmc_card_blockaddr(c) ((c)->state & MMC_STATE_BLOCKADDR)
#define mmc_card_set_present(c) ((c)->state |= MMC_STATE_PRESENT)
#define mmc_card_set_dead(c) ((c)->state |= MMC_STATE_DEAD)
@@ -94,6 +96,7 @@ struct mmc_card {
#define mmc_card_set_sd(c) ((c)->state |= MMC_STATE_SDCARD)
#define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)
#define mmc_card_set_highspeed(c) ((c)->state |= MMC_STATE_HIGHSPEED)
+#define mmc_card_set_blockaddr(c) ((c)->state |= MMC_STATE_BLOCKADDR)
#define mmc_card_name(c) ((c)->cid.prod_name)
#define mmc_card_id(c) ((c)->dev.bus_id)
diff -puN include/linux/mmc/mmc.h~mmc-add-support-for-sdhc-cards include/linux/mmc/mmc.h
--- a/include/linux/mmc/mmc.h~mmc-add-support-for-sdhc-cards
+++ a/include/linux/mmc/mmc.h
@@ -43,6 +43,7 @@ struct mmc_command {
#define MMC_RSP_R2 (MMC_RSP_PRESENT|MMC_RSP_136|MMC_RSP_CRC)
#define MMC_RSP_R3 (MMC_RSP_PRESENT)
#define MMC_RSP_R6 (MMC_RSP_PRESENT|MMC_RSP_CRC)
+#define MMC_RSP_R7 (MMC_RSP_PRESENT|MMC_RSP_CRC)
#define mmc_resp_type(cmd) ((cmd)->flags & (MMC_RSP_PRESENT|MMC_RSP_136|MMC_RSP_CRC|MMC_RSP_BUSY|MMC_RSP_OPCODE))
diff -puN include/linux/mmc/protocol.h~mmc-add-support-for-sdhc-cards include/linux/mmc/protocol.h
--- a/include/linux/mmc/protocol.h~mmc-add-support-for-sdhc-cards
+++ a/include/linux/mmc/protocol.h
@@ -79,9 +79,12 @@
#define MMC_GEN_CMD 56 /* adtc [0] RD/WR R1 */
/* SD commands type argument response */
- /* class 8 */
+ /* class 0 */
/* This is basically the same command as for MMC with some quirks. */
#define SD_SEND_RELATIVE_ADDR 3 /* bcr R6 */
+#define SD_SEND_IF_COND 8 /* bcr [11:0] See below R7 */
+
+ /* class 10 */
#define SD_SWITCH 6 /* adtc [31:0] See below R1 */
/* Application commands */
@@ -115,6 +118,14 @@
*/
/*
+ * SD_SEND_IF_COND argument format:
+ *
+ * [31:12] Reserved (0)
+ * [11:8] Host Voltage Supply Flags
+ * [7:0] Check Pattern (0xAA)
+ */
+
+/*
MMC status in R1
Type
e : error bit
_
Patches currently in -mm which might be from philipl@xxxxxxxxx are
mmc-add-support-for-sdhc-cards.patch
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