mmc: dw_mmc: Remove old card detect infrastructure

The dw_mmc driver had a bunch of code that ran whenever a card was
ejected and inserted.  However, this code was old and crufty and
should be removed.  Some evidence that it's really not needed:

1. Is is supposed to be legal to use 'cd-gpio' on dw_mmc instead of
   using the built-in card detect mechanism.  The 'cd-gpio' code
   doesn't run any of the crufty old code but yet still works.

2. While looking at this, I realized that my old change (369ac86 mmc:
   dw_mmc: don't queue up a card detect at slot startup) actually
   castrated the old code a little bit already and nobody noticed.
   Specifically "last_detect_state" was left as 0 at bootup.  That
   means that on the first card removal none of the crufty code ran.

3. I can run "while true; do dd if=/dev/mmcblk1 of=/dev/null; done"
   while ejecting and inserting an SD Card and the world doesn't
   explode.

If some of the crufty old code is actually needed, we should justify
it and also put it in some place where it will be run even with
"cd-gpio".

Note that in my case I'm using the "cd-gpio" mechanism but for various
reasons the hardware triggers a dw_mmc "card detect" at bootup.  That
was actually causing a real bug.  The card detect workqueue was
running while the system was trying to enumerate the card.  The
"present != slot->last_detect_state" triggered and we were doing all
kinds of crazy stuff and messing up enumeration.  The new mechanism of
just asking the core to check the card is much safer and then the
bogus interrupt doesn't hurt.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Tested-by: Jaehoon Chung <jh80.chung@samsung.com>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Tested-by: alim.akhtar <alim.akhtar@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 0 insertions, 2 deletions

diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
index 01b99e8a9190..71d499557edc 100644
--- a/drivers/mmc/host/dw_mmc.h
+++ b/drivers/mmc/host/dw_mmc.h
@@ -214,7 +214,6 @@ extern int dw_mci_resume(struct dw_mci *host);
  *	with CONFIG_MMC_CLKGATE.
  * @flags: Random state bits associated with the slot.
  * @id: Number of this slot.
- * @last_detect_state: Most recently observed card detect state.
  */
 struct dw_mci_slot {
 	struct mmc_host		*mmc;
@@ -234,7 +233,6 @@ struct dw_mci_slot {
 #define DW_MMC_CARD_PRESENT	0
 #define DW_MMC_CARD_NEED_INIT	1
 	int			id;
-	int			last_detect_state;
 };
 
 struct dw_mci_tuning_data {