mmc: deprecate mmc bus topology

The classic MMC bus was defined as multi card bus
system, which is reflected in the design in the MMC
layer.

When SD showed up, the bus topology was abandoned
and a star topology (one card per host) was mandated.
MMC version 4 has followed this, officially deprecating
the bus topology.

As we do not have any known users of the bus
topology we can remove support for it. This will
simplify the code and rectify some incorrect
assumptions in the newer additions.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

drivers/mmc/card/block.c

@@ -226,8 +226,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 	struct mmc_blk_request brq;
 	int ret = 1, sg_pos, data_size;
 
-	if (mmc_card_claim_host(card))
-		goto flush_queue;
+	mmc_claim_host(card->host);
 
 	do {
 		struct mmc_command cmd;
@@ -357,7 +356,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 		spin_unlock_irq(&md->lock);
 	} while (ret);
 
-	mmc_card_release_host(card);
+	mmc_release_host(card->host);
 
 	return 1;
 
@@ -393,9 +392,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 		spin_unlock_irq(&md->lock);
 	}
 
-flush_queue:
-
-	mmc_card_release_host(card);
+	mmc_release_host(card->host);
 
 	spin_lock_irq(&md->lock);
 	while (ret) {
@@ -526,12 +523,12 @@ mmc_blk_set_blksize(struct mmc_blk_data *md, struct mmc_card *card)
 	if (mmc_card_blockaddr(card))
 		return 0;
 
-	mmc_card_claim_host(card);
+	mmc_claim_host(card->host);
 	cmd.opcode = MMC_SET_BLOCKLEN;
 	cmd.arg = 1 << md->block_bits;
 	cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
 	err = mmc_wait_for_cmd(card->host, &cmd, 5);
-	mmc_card_release_host(card);
+	mmc_release_host(card->host);
 
 	if (err) {
 		printk(KERN_ERR "%s: unable to set block size to %d: %d\n",

include/linux/mmc/card.h

@@ -61,7 +61,6 @@ struct mmc_host;
  * MMC device
  */
 struct mmc_card {
-	struct list_head	node;		/* node in hosts devices list */
 	struct mmc_host		*host;		/* the host this device belongs to */
 	struct device		dev;		/* the device */
 	unsigned int		rca;		/* relative card address of device */
@@ -123,11 +122,4 @@ struct mmc_driver {
 extern int mmc_register_driver(struct mmc_driver *);
 extern void mmc_unregister_driver(struct mmc_driver *);
 
-static inline int mmc_card_claim_host(struct mmc_card *card)
-{
-	return __mmc_claim_host(card->host, card);
-}
-
-#define mmc_card_release_host(c)	mmc_release_host((c)->host)
-
 #endif

include/linux/mmc/host.h

@@ -138,14 +138,12 @@ struct mmc_host {
 #define MMC_MODE_MMC		0
 #define MMC_MODE_SD		1
 
-	struct list_head	cards;		/* devices attached to this host */
+	struct mmc_card		*card;		/* device attached to this host */
 
 	wait_queue_head_t	wq;
 	spinlock_t		lock;		/* claimed lock */
 	unsigned int		claimed:1;	/* host exclusively claimed */
 
-	struct mmc_card		*card_selected;	/* the selected MMC card */
-
 	struct delayed_work	detect;
 #ifdef CONFIG_MMC_DEBUG
 	unsigned int		removed:1;	/* host is being removed */

include/linux/mmc/mmc.h

@@ -8,7 +8,6 @@
 #ifndef MMC_H
 #define MMC_H
 
-#include <linux/list.h>
 #include <linux/interrupt.h>
 #include <linux/device.h>
 
@@ -107,13 +106,7 @@ extern int mmc_wait_for_app_cmd(struct mmc_host *, unsigned int,
 
 extern void mmc_set_data_timeout(struct mmc_data *, const struct mmc_card *, int);
 
-extern int __mmc_claim_host(struct mmc_host *host, struct mmc_card *card);
-
-static inline void mmc_claim_host(struct mmc_host *host)
-{
-	__mmc_claim_host(host, (struct mmc_card *)-1);
-}
-
+extern void mmc_claim_host(struct mmc_host *host);
 extern void mmc_release_host(struct mmc_host *host);
 
 #endif