MMC core learns about SPI
Teach the MMC/SD/SDIO core about using SPI mode.
- Use mmc_host_is_spi() so enumeration works through SPI signaling
and protocols, not just the native versions.
- Provide the SPI response type flags with each request issued,
including requests from the new lock/unlock code.
- Understand that cmd->resp[0] and mmc_get_status() results for SPI
return different values than for "native" MMC/SD protocol; this
affects resetting, checking card lock status, and some others.
- Understand that some commands act a bit differently ... notably:
* OP_COND command doesn't return the OCR
* APP_CMD status doesn't have an R1_APP_CMD analogue
Those changes required some new and updated primitives:
- Provide utilities to access two SPI-only requests, and one
request that wasn't previously needed:
* mmc_spi_read_ocr() ... SPI only
* mmc_spi_set_crc() ... SPI only (override by module parm)
* mmc_send_cid() ... for use without broadcast mode
- Updated internal routines:
* Previous mmc_send_csd() modified into mmc_send_cxd_native();
it uses native "R2" responses, which include 16 bytes of data.
* Previous mmc_send_ext_csd() becomes new mmc_send_cxd_data()
helper for command-and-data access
* Bugfix to that mmc_send_cxd_data() code: dma-to-stack is
unsafe/nonportable, so kmalloc a bounce buffer instead.
- Modified mmc_send_ext_csd() now uses mmc_send_cxd_data() helper
- Modified mmc_send_csd(), and new mmc_spi_send_cid(), routines use
those helper routines based on whether they're native or SPI
The newest categories of cards supported by the MMC stack aren't expected
to work yet with SPI: MMC or SD cards with over 4GB data, and SDIO.
All those cards support SPI mode, so eventually they should work too.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 2f3fb99..87a50f4 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -270,6 +270,15 @@
goto err;
/*
+ * For SPI, enable CRC as appropriate.
+ */
+ if (mmc_host_is_spi(host)) {
+ err = mmc_spi_set_crc(host, use_spi_crc);
+ if (err)
+ goto err;
+ }
+
+ /*
* The number of functions on the card is encoded inside
* the ocr.
*/
@@ -290,20 +299,24 @@
host->card = card;
/*
- * Set card RCA.
+ * For native busses: set card RCA and quit open drain mode.
*/
- err = mmc_send_relative_addr(host, &card->rca);
- if (err)
- goto remove;
+ if (!mmc_host_is_spi(host)) {
+ err = mmc_send_relative_addr(host, &card->rca);
+ if (err)
+ goto remove;
- mmc_set_bus_mode(host, MMC_BUSMODE_PUSHPULL);
+ mmc_set_bus_mode(host, MMC_BUSMODE_PUSHPULL);
+ }
/*
* Select card, as all following commands rely on that.
*/
- err = mmc_select_card(card);
- if (err)
- goto remove;
+ if (!mmc_host_is_spi(host)) {
+ err = mmc_select_card(card);
+ if (err)
+ goto remove;
+ }
/*
* Read the common registers.