mmc: add bus handler

Delegate protocol handling to "bus handlers". This allows the core to
just handle the task of arbitrating the bus. Initialisation and
pampering of cards is now done by the different bus handlers.

This design also allows MMC and SD (and later SDIO) to be more cleanly
separated, allowing easier maintenance.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

drivers/mmc/core/Makefile

@@ -7,5 +7,5 @@ ifeq ($(CONFIG_MMC_DEBUG),y)
 endif
 
 obj-$(CONFIG_MMC)		+= mmc_core.o
-mmc_core-y			:= core.o sysfs.o mmc_ops.o sd_ops.o
+mmc_core-y			:= core.o sysfs.o mmc.o mmc_ops.o sd.o sd_ops.o
 

drivers/mmc/core/core.h

@@ -15,7 +15,44 @@
 
 #define MMC_CMD_RETRIES        3
 
+struct mmc_bus_ops {
+	void (*remove)(struct mmc_host *);
+	void (*detect)(struct mmc_host *);
+};
+
+void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);
+void mmc_detach_bus(struct mmc_host *host);
+
+void __mmc_release_bus(struct mmc_host *host);
+
+static inline void mmc_bus_get(struct mmc_host *host)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&host->lock, flags);
+	host->bus_refs++;
+	spin_unlock_irqrestore(&host->lock, flags);
+}
+
+static inline void mmc_bus_put(struct mmc_host *host)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&host->lock, flags);
+	host->bus_refs--;
+	if ((host->bus_refs == 0) && host->bus_ops)
+		__mmc_release_bus(host);
+	spin_unlock_irqrestore(&host->lock, flags);
+}
+
 void mmc_set_chip_select(struct mmc_host *host, int mode);
+void mmc_set_clock(struct mmc_host *host, unsigned int hz);
+void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode);
+void mmc_set_bus_width(struct mmc_host *host, unsigned int width);
+u32 mmc_select_voltage(struct mmc_host *host, u32 ocr);
+void mmc_set_timing(struct mmc_host *host, unsigned int timing);
+
+struct mmc_card *mmc_alloc_card(struct mmc_host *host);
 
 static inline void mmc_delay(unsigned int ms)
 {

drivers/mmc/core/sd.c

+/*
+ *  linux/drivers/mmc/sd.c
+ *
+ *  Copyright (C) 2003-2004 Russell King, All Rights Reserved.
+ *  SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
+ *  Copyright (C) 2005-2007 Pierre Ossman, All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/err.h>
+
+#include <linux/mmc/host.h>
+#include <linux/mmc/card.h>
+#include <linux/mmc/mmc.h>
+
+#include "core.h"
+#include "sysfs.h"
+#include "mmc_ops.h"
+#include "sd_ops.h"
+
+#include "core.h"
+
+static const unsigned int tran_exp[] = {
+	10000,		100000,		1000000,	10000000,
+	0,		0,		0,		0
+};
+
+static const unsigned char tran_mant[] = {
+	0,	10,	12,	13,	15,	20,	25,	30,
+	35,	40,	45,	50,	55,	60,	70,	80,
+};
+
+static const unsigned int tacc_exp[] = {
+	1,	10,	100,	1000,	10000,	100000,	1000000, 10000000,
+};
+
+static const unsigned int tacc_mant[] = {
+	0,	10,	12,	13,	15,	20,	25,	30,
+	35,	40,	45,	50,	55,	60,	70,	80,
+};
+
+#define UNSTUFF_BITS(resp,start,size)					\
+	({								\
+		const int __size = size;				\
+		const u32 __mask = (__size < 32 ? 1 << __size : 0) - 1;	\
+		const int __off = 3 - ((start) / 32);			\
+		const int __shft = (start) & 31;			\
+		u32 __res;						\
+									\
+		__res = resp[__off] >> __shft;				\
+		if (__size + __shft > 32)				\
+			__res |= resp[__off-1] << ((32 - __shft) % 32);	\
+		__res & __mask;						\
+	})
+
+/*
+ * Given the decoded CSD structure, decode the raw CID to our CID structure.
+ */
+static void mmc_decode_cid(struct mmc_card *card)
+{
+	u32 *resp = card->raw_cid;
+
+	memset(&card->cid, 0, sizeof(struct mmc_cid));
+
+	/*
+	 * SD doesn't currently have a version field so we will
+	 * have to assume we can parse this.
+	 */
+	card->cid.manfid		= UNSTUFF_BITS(resp, 120, 8);
+	card->cid.oemid			= UNSTUFF_BITS(resp, 104, 16);
+	card->cid.prod_name[0]		= UNSTUFF_BITS(resp, 96, 8);
+	card->cid.prod_name[1]		= UNSTUFF_BITS(resp, 88, 8);
+	card->cid.prod_name[2]		= UNSTUFF_BITS(resp, 80, 8);
+	card->cid.prod_name[3]		= UNSTUFF_BITS(resp, 72, 8);
+	card->cid.prod_name[4]		= UNSTUFF_BITS(resp, 64, 8);
+	card->cid.hwrev			= UNSTUFF_BITS(resp, 60, 4);
+	card->cid.fwrev			= UNSTUFF_BITS(resp, 56, 4);
+	card->cid.serial		= UNSTUFF_BITS(resp, 24, 32);
+	card->cid.year			= UNSTUFF_BITS(resp, 12, 8);
+	card->cid.month			= UNSTUFF_BITS(resp, 8, 4);
+
+	card->cid.year += 2000; /* SD cards year offset */
+}
+
+/*
+ * Given a 128-bit response, decode to our card CSD structure.
+ */
+static void mmc_decode_csd(struct mmc_card *card)
+{
+	struct mmc_csd *csd = &card->csd;
+	unsigned int e, m, csd_struct;
+	u32 *resp = card->raw_csd;
+
+	csd_struct = UNSTUFF_BITS(resp, 126, 2);
+
+	switch (csd_struct) {
+	case 0:
+		m = UNSTUFF_BITS(resp, 115, 4);
+		e = UNSTUFF_BITS(resp, 112, 3);
+		csd->tacc_ns	 = (tacc_exp[e] * tacc_mant[m] + 9) / 10;
+		csd->tacc_clks	 = UNSTUFF_BITS(resp, 104, 8) * 100;
+
+		m = UNSTUFF_BITS(resp, 99, 4);
+		e = UNSTUFF_BITS(resp, 96, 3);
+		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);
+
+		csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
+		csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
+		csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
+		csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
+		csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3);
+		csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
+		csd->write_partial = UNSTUFF_BITS(resp, 21, 1);
+		break;
+	case 1:
+		/*
+		 * This is a block-addressed SDHC card. Most
+		 * interesting fields are unused and have fixed
+		 * values. To avoid getting tripped by buggy cards,
+		 * we assume those fixed values ourselves.
+		 */
+		mmc_card_set_blockaddr(card);
+
+		csd->tacc_ns	 = 0; /* Unused */
+		csd->tacc_clks	 = 0; /* Unused */
+
+		m = UNSTUFF_BITS(resp, 99, 4);
+		e = UNSTUFF_BITS(resp, 96, 3);
+		csd->max_dtr	  = tran_exp[e] * tran_mant[m];
+		csd->cmdclass	  = UNSTUFF_BITS(resp, 84, 12);
+
+		m = UNSTUFF_BITS(resp, 48, 22);
+		csd->capacity     = (1 + m) << 10;
+
+		csd->read_blkbits = 9;
+		csd->read_partial = 0;
+		csd->write_misalign = 0;
+		csd->read_misalign = 0;
+		csd->r2w_factor = 4; /* Unused */
+		csd->write_blkbits = 9;
+		csd->write_partial = 0;
+		break;
+	default:
+		printk("%s: unrecognised CSD structure version %d\n",
+			mmc_hostname(card->host), csd_struct);
+		mmc_card_set_bad(card);
+		return;
+	}
+}
+
+/*
+ * Given a 64-bit response, decode to our card SCR structure.
+ */
+static void mmc_decode_scr(struct mmc_card *card)
+{
+	struct sd_scr *scr = &card->scr;
+	unsigned int scr_struct;
+	u32 resp[4];
+
+	BUG_ON(!mmc_card_sd(card));
+
+	resp[3] = card->raw_scr[1];
+	resp[2] = card->raw_scr[0];
+
+	scr_struct = UNSTUFF_BITS(resp, 60, 4);
+	if (scr_struct != 0) {
+		printk("%s: unrecognised SCR structure version %d\n",
+			mmc_hostname(card->host), scr_struct);
+		mmc_card_set_bad(card);
+		return;
+	}
+
+	scr->sda_vsn = UNSTUFF_BITS(resp, 56, 4);
+	scr->bus_widths = UNSTUFF_BITS(resp, 48, 4);
+}
+
+/*
+ * Test if the card supports high-speed mode and, if so, switch to it.
+ */
+static int mmc_switch_hs(struct mmc_card *card)
+{
+	int err;
+	u8 *status;
+
+	if (!(card->host->caps & MMC_CAP_SD_HIGHSPEED))
+		return MMC_ERR_NONE;
+
+	err = MMC_ERR_FAILED;
+
+	status = kmalloc(64, GFP_KERNEL);
+	if (!status) {
+		printk("%s: could not allocate a buffer for switch "
+		       "capabilities.\n",
+			mmc_hostname(card->host));
+		return err;
+	}
+
+	err = mmc_sd_switch(card, 0, 0, 1, status);
+	if (err != MMC_ERR_NONE) {
+		/*
+		 * Card not supporting high-speed will ignore the
+		 * command.
+		 */
+		if (err == MMC_ERR_TIMEOUT)
+			err = MMC_ERR_NONE;
+		goto out;
+	}
+
+	if (status[13] & 0x02)
+		card->sw_caps.hs_max_dtr = 50000000;
+
+	err = mmc_sd_switch(card, 1, 0, 1, status);
+	if (err != MMC_ERR_NONE)
+		goto out;
+
+	if ((status[16] & 0xF) != 1) {
+		printk(KERN_WARNING "%s: Problem switching card "
+			"into high-speed mode!\n",
+			mmc_hostname(card->host));
+	} else {
+		mmc_card_set_highspeed(card);
+		mmc_set_timing(card->host, MMC_TIMING_SD_HS);
+	}
+
+out:
+	kfree(status);
+
+	return err;
+}
+
+/*
+ * Host is being removed. Free up the current card.
+ */
+static void mmc_sd_remove(struct mmc_host *host)
+{
+	BUG_ON(!host);
+	BUG_ON(!host->card);
+
+	mmc_remove_card(host->card);
+	host->card = NULL;
+}
+
+/*
+ * Card detection callback from host.
+ */
+static void mmc_sd_detect(struct mmc_host *host)
+{
+	int err;
+
+	BUG_ON(!host);
+	BUG_ON(!host->card);
+
+	mmc_claim_host(host);
+
+	/*
+	 * Just check if our card has been removed.
+	 */
+	err = mmc_send_status(host->card, NULL);
+
+	mmc_release_host(host);
+
+	if (err != MMC_ERR_NONE) {
+		mmc_remove_card(host->card);
+		host->card = NULL;
+
+		mmc_claim_host(host);
+		mmc_detach_bus(host);
+		mmc_release_host(host);
+	}
+}
+
+static const struct mmc_bus_ops mmc_sd_ops = {
+	.remove = mmc_sd_remove,
+	.detect = mmc_sd_detect,
+};
+
+/*
+ * Starting point for SD card init.
+ */
+int mmc_attach_sd(struct mmc_host *host, u32 ocr)
+{
+	struct mmc_card *card;
+	int err;
+	u32 cid[4];
+	unsigned int max_dtr;
+
+	BUG_ON(!host);
+	BUG_ON(!host->claimed);
+
+	mmc_attach_bus(host, &mmc_sd_ops);
+
+	host->ocr = mmc_select_voltage(host, ocr);
+
+	/*
+	 * Can we support the voltage(s) of the card(s)?
+	 */
+	if (!host->ocr)
+		goto err;
+
+	/*
+	 * Since we're changing the OCR value, we seem to
+	 * need to tell some cards to go back to the idle
+	 * state.  We wait 1ms to give cards time to
+	 * respond.
+	 */
+	mmc_go_idle(host);
+
+	/*
+	 * If SD_SEND_IF_COND indicates an SD 2.0
+	 * compliant card and we should set bit 30
+	 * of the ocr to indicate that we can handle
+	 * block-addressed SDHC cards.
+	 */
+	err = mmc_send_if_cond(host, host->ocr);
+	if (err == MMC_ERR_NONE)
+		ocr = host->ocr | (1 << 30);
+
+	mmc_send_app_op_cond(host, ocr, NULL);
+
+	/*
+	 * Fetch CID from card.
+	 */
+	err = mmc_all_send_cid(host, cid);
+	if (err != MMC_ERR_NONE)
+		goto err;
+
+	/*
+	 * Allocate card structure.
+	 */
+	card = mmc_alloc_card(host);
+	if (IS_ERR(card))
+		goto err;
+
+	card->type = MMC_TYPE_SD;
+	memcpy(card->raw_cid, cid, sizeof(card->raw_cid));
+
+	/*
+	 * Set card RCA.
+	 */
+	err = mmc_send_relative_addr(host, &card->rca);
+	if (err != MMC_ERR_NONE)
+		goto free_card;
+
+	mmc_set_bus_mode(host, MMC_BUSMODE_PUSHPULL);
+
+	/*
+	 * Fetch CSD from card.
+	 */
+	err = mmc_send_csd(card, card->raw_csd);
+	if (err != MMC_ERR_NONE)
+		goto free_card;
+
+	mmc_decode_csd(card);
+	mmc_decode_cid(card);
+
+	/*
+	 * Fetch SCR from card.
+	 */
+	err = mmc_select_card(card);
+	if (err != MMC_ERR_NONE)
+		goto free_card;
+
+	err = mmc_app_send_scr(card, card->raw_scr);
+	if (err != MMC_ERR_NONE)
+		goto free_card;
+
+	mmc_decode_scr(card);
+
+	/*
+	 * Check if card can be switched into high-speed mode.
+	 */
+	err = mmc_switch_hs(card);
+	if (err != MMC_ERR_NONE)
+		goto free_card;
+
+	/*
+	 * Compute bus speed.
+	 */
+	max_dtr = (unsigned int)-1;
+
+	if (mmc_card_highspeed(card)) {
+		if (max_dtr > card->sw_caps.hs_max_dtr)
+			max_dtr = card->sw_caps.hs_max_dtr;
+	} else if (max_dtr > card->csd.max_dtr) {
+		max_dtr = card->csd.max_dtr;
+	}
+
+	mmc_set_clock(host, max_dtr);
+
+	/*
+	 * Switch to wider bus (if supported).
+	 */
+	if ((host->caps && MMC_CAP_4_BIT_DATA) &&
+		(card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
+		err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
+		if (err != MMC_ERR_NONE)
+			goto free_card;
+
+		mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
+	}
+
+	host->card = card;
+
+	mmc_release_host(host);
+
+	err = mmc_register_card(card);
+	if (err)
+		goto reclaim_host;
+
+	return 0;
+
+reclaim_host:
+	mmc_claim_host(host);
+free_card:
+	mmc_remove_card(card);
+	host->card = NULL;
+err:
+	mmc_detach_bus(host);
+	mmc_release_host(host);
+
+	return 0;
+}
+

include/linux/mmc/host.h

@@ -131,6 +131,8 @@ struct mmc_host {
 	unsigned int		max_blk_count;	/* maximum number of blocks in one req */
 
 	/* private data */
+	spinlock_t		lock;		/* lock for claim and bus ops */
+
 	struct mmc_ios		ios;		/* current io bus settings */
 	u32			ocr;		/* the current OCR setting */
 
@@ -141,7 +143,6 @@ struct mmc_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 delayed_work	detect;
@@ -149,6 +150,10 @@ struct mmc_host {
 	unsigned int		removed:1;	/* host is being removed */
 #endif
 
+	const struct mmc_bus_ops *bus_ops;	/* current bus driver */
+	unsigned int		bus_refs;	/* reference counter */
+	unsigned int		bus_dead:1;	/* bus has been released */
+
 	unsigned long		private[0] ____cacheline_aligned;
 };