mmc: block: Move files to core

Once upon a time it made sense to keep the mmc block device driver and its
related code, in its own directory called card. Over time, more an more
functions/structures have become shared through generic mmc header files,
between the core and the card directory. In other words, the relationship
between them has become closer.

By sharing functions/structures via generic header files, it becomes easy
for outside users to abuse them. In a way to avoid that from happen, let's
move the files from card directory into the core directory, as it enables
us to move definitions of functions/structures into mmc core specific
header files.

Note, this is only the first step in providing a cleaner mmc interface for
outside users. Following changes will do the actual cleanup, as that is not
part of this change.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

drivers/mmc/core/Kconfig

@@ -22,3 +22,69 @@ config PWRSEQ_SIMPLE
 
 	  This driver can also be built as a module. If so, the module
 	  will be called pwrseq_simple.
+
+config MMC_BLOCK
+	tristate "MMC block device driver"
+	depends on BLOCK
+	default y
+	help
+	  Say Y here to enable the MMC block device driver support.
+	  This provides a block device driver, which you can use to
+	  mount the filesystem. Almost everyone wishing MMC support
+	  should say Y or M here.
+
+config MMC_BLOCK_MINORS
+	int "Number of minors per block device"
+	depends on MMC_BLOCK
+	range 4 256
+	default 8
+	help
+	  Number of minors per block device. One is needed for every
+	  partition on the disk (plus one for the whole disk).
+
+	  Number of total MMC minors available is 256, so your number
+	  of supported block devices will be limited to 256 divided
+	  by this number.
+
+	  Default is 8 to be backwards compatible with previous
+	  hardwired device numbering.
+
+	  If unsure, say 8 here.
+
+config MMC_BLOCK_BOUNCE
+	bool "Use bounce buffer for simple hosts"
+	depends on MMC_BLOCK
+	default y
+	help
+	  SD/MMC is a high latency protocol where it is crucial to
+	  send large requests in order to get high performance. Many
+	  controllers, however, are restricted to continuous memory
+	  (i.e. they can't do scatter-gather), something the kernel
+	  rarely can provide.
+
+	  Say Y here to help these restricted hosts by bouncing
+	  requests back and forth from a large buffer. You will get
+	  a big performance gain at the cost of up to 64 KiB of
+	  physical memory.
+
+	  If unsure, say Y here.
+
+config SDIO_UART
+	tristate "SDIO UART/GPS class support"
+	depends on TTY
+	help
+	  SDIO function driver for SDIO cards that implements the UART
+	  class, as well as the GPS class which appears like a UART.
+
+config MMC_TEST
+	tristate "MMC host test driver"
+	help
+	  Development driver that performs a series of reads and writes
+	  to a memory card in order to expose certain well known bugs
+	  in host controllers. The tests are executed by writing to the
+	  "test" file in debugfs under each card. Note that whatever is
+	  on your card will be overwritten by these tests.
+
+	  This driver is only of interest to those developing or
+	  testing a host driver. Most people should say N here.
+

drivers/mmc/core/Makefile

@@ -12,3 +12,7 @@ mmc_core-$(CONFIG_OF)		+= pwrseq.o
 obj-$(CONFIG_PWRSEQ_SIMPLE)	+= pwrseq_simple.o
 obj-$(CONFIG_PWRSEQ_EMMC)	+= pwrseq_emmc.o
 mmc_core-$(CONFIG_DEBUG_FS)	+= debugfs.o
+obj-$(CONFIG_MMC_BLOCK)		+= mmc_block.o
+mmc_block-objs			:= block.o queue.o
+obj-$(CONFIG_MMC_TEST)		+= mmc_test.o
+obj-$(CONFIG_SDIO_UART)		+= sdio_uart.o

drivers/mmc/core/block.h

@@ -0,0 +1 @@
+int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req);

drivers/mmc/core/queue.c

@@ -0,0 +1,489 @@
+/*
+ *  Copyright (C) 2003 Russell King, All Rights Reserved.
+ *  Copyright 2006-2007 Pierre Ossman
+ *
+ * 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/slab.h>
+#include <linux/module.h>
+#include <linux/blkdev.h>
+#include <linux/freezer.h>
+#include <linux/kthread.h>
+#include <linux/scatterlist.h>
+#include <linux/dma-mapping.h>
+
+#include <linux/mmc/card.h>
+#include <linux/mmc/host.h>
+
+#include "queue.h"
+#include "block.h"
+
+#define MMC_QUEUE_BOUNCESZ	65536
+
+/*
+ * Prepare a MMC request. This just filters out odd stuff.
+ */
+static int mmc_prep_request(struct request_queue *q, struct request *req)
+{
+	struct mmc_queue *mq = q->queuedata;
+
+	/*
+	 * We only like normal block requests and discards.
+	 */
+	if (req->cmd_type != REQ_TYPE_FS && req_op(req) != REQ_OP_DISCARD &&
+	    req_op(req) != REQ_OP_SECURE_ERASE) {
+		blk_dump_rq_flags(req, "MMC bad request");
+		return BLKPREP_KILL;
+	}
+
+	if (mq && (mmc_card_removed(mq->card) || mmc_access_rpmb(mq)))
+		return BLKPREP_KILL;
+
+	req->cmd_flags |= REQ_DONTPREP;
+
+	return BLKPREP_OK;
+}
+
+static int mmc_queue_thread(void *d)
+{
+	struct mmc_queue *mq = d;
+	struct request_queue *q = mq->queue;
+	struct mmc_context_info *cntx = &mq->card->host->context_info;
+
+	current->flags |= PF_MEMALLOC;
+
+	down(&mq->thread_sem);
+	do {
+		struct request *req = NULL;
+
+		spin_lock_irq(q->queue_lock);
+		set_current_state(TASK_INTERRUPTIBLE);
+		req = blk_fetch_request(q);
+		mq->asleep = false;
+		cntx->is_waiting_last_req = false;
+		cntx->is_new_req = false;
+		if (!req) {
+			/*
+			 * Dispatch queue is empty so set flags for
+			 * mmc_request_fn() to wake us up.
+			 */
+			if (mq->mqrq_prev->req)
+				cntx->is_waiting_last_req = true;
+			else
+				mq->asleep = true;
+		}
+		mq->mqrq_cur->req = req;
+		spin_unlock_irq(q->queue_lock);
+
+		if (req || mq->mqrq_prev->req) {
+			bool req_is_special = mmc_req_is_special(req);
+
+			set_current_state(TASK_RUNNING);
+			mmc_blk_issue_rq(mq, req);
+			cond_resched();
+			if (mq->flags & MMC_QUEUE_NEW_REQUEST) {
+				mq->flags &= ~MMC_QUEUE_NEW_REQUEST;
+				continue; /* fetch again */
+			}
+
+			/*
+			 * Current request becomes previous request
+			 * and vice versa.
+			 * In case of special requests, current request
+			 * has been finished. Do not assign it to previous
+			 * request.
+			 */
+			if (req_is_special)
+				mq->mqrq_cur->req = NULL;
+
+			mq->mqrq_prev->brq.mrq.data = NULL;
+			mq->mqrq_prev->req = NULL;
+			swap(mq->mqrq_prev, mq->mqrq_cur);
+		} else {
+			if (kthread_should_stop()) {
+				set_current_state(TASK_RUNNING);
+				break;
+			}
+			up(&mq->thread_sem);
+			schedule();
+			down(&mq->thread_sem);
+		}
+	} while (1);
+	up(&mq->thread_sem);
+
+	return 0;
+}
+
+/*
+ * Generic MMC request handler.  This is called for any queue on a
+ * particular host.  When the host is not busy, we look for a request
+ * on any queue on this host, and attempt to issue it.  This may
+ * not be the queue we were asked to process.
+ */
+static void mmc_request_fn(struct request_queue *q)
+{
+	struct mmc_queue *mq = q->queuedata;
+	struct request *req;
+	struct mmc_context_info *cntx;
+
+	if (!mq) {
+		while ((req = blk_fetch_request(q)) != NULL) {
+			req->cmd_flags |= REQ_QUIET;
+			__blk_end_request_all(req, -EIO);
+		}
+		return;
+	}
+
+	cntx = &mq->card->host->context_info;
+
+	if (cntx->is_waiting_last_req) {
+		cntx->is_new_req = true;
+		wake_up_interruptible(&cntx->wait);
+	}
+
+	if (mq->asleep)
+		wake_up_process(mq->thread);
+}
+
+static struct scatterlist *mmc_alloc_sg(int sg_len, int *err)
+{
+	struct scatterlist *sg;
+
+	sg = kmalloc(sizeof(struct scatterlist)*sg_len, GFP_KERNEL);
+	if (!sg)
+		*err = -ENOMEM;
+	else {
+		*err = 0;
+		sg_init_table(sg, sg_len);
+	}
+
+	return sg;
+}
+
+static void mmc_queue_setup_discard(struct request_queue *q,
+				    struct mmc_card *card)
+{
+	unsigned max_discard;
+
+	max_discard = mmc_calc_max_discard(card);
+	if (!max_discard)
+		return;
+
+	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
+	blk_queue_max_discard_sectors(q, max_discard);
+	if (card->erased_byte == 0 && !mmc_can_discard(card))
+		q->limits.discard_zeroes_data = 1;
+	q->limits.discard_granularity = card->pref_erase << 9;
+	/* granularity must not be greater than max. discard */
+	if (card->pref_erase > max_discard)
+		q->limits.discard_granularity = 0;
+	if (mmc_can_secure_erase_trim(card))
+		queue_flag_set_unlocked(QUEUE_FLAG_SECERASE, q);
+}
+
+#ifdef CONFIG_MMC_BLOCK_BOUNCE
+static bool mmc_queue_alloc_bounce_bufs(struct mmc_queue *mq,
+					unsigned int bouncesz)
+{
+	int i;
+
+	for (i = 0; i < mq->qdepth; i++) {
+		mq->mqrq[i].bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
+		if (!mq->mqrq[i].bounce_buf)
+			goto out_err;
+	}
+
+	return true;
+
+out_err:
+	while (--i >= 0) {
+		kfree(mq->mqrq[i].bounce_buf);
+		mq->mqrq[i].bounce_buf = NULL;
+	}
+	pr_warn("%s: unable to allocate bounce buffers\n",
+		mmc_card_name(mq->card));
+	return false;
+}
+
+static int mmc_queue_alloc_bounce_sgs(struct mmc_queue *mq,
+				      unsigned int bouncesz)
+{
+	int i, ret;
+
+	for (i = 0; i < mq->qdepth; i++) {
+		mq->mqrq[i].sg = mmc_alloc_sg(1, &ret);
+		if (ret)
+			return ret;
+
+		mq->mqrq[i].bounce_sg = mmc_alloc_sg(bouncesz / 512, &ret);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+#endif
+
+static int mmc_queue_alloc_sgs(struct mmc_queue *mq, int max_segs)
+{
+	int i, ret;
+
+	for (i = 0; i < mq->qdepth; i++) {
+		mq->mqrq[i].sg = mmc_alloc_sg(max_segs, &ret);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static void mmc_queue_req_free_bufs(struct mmc_queue_req *mqrq)
+{
+	kfree(mqrq->bounce_sg);
+	mqrq->bounce_sg = NULL;
+
+	kfree(mqrq->sg);
+	mqrq->sg = NULL;
+
+	kfree(mqrq->bounce_buf);
+	mqrq->bounce_buf = NULL;
+}
+
+static void mmc_queue_reqs_free_bufs(struct mmc_queue *mq)
+{
+	int i;
+
+	for (i = 0; i < mq->qdepth; i++)
+		mmc_queue_req_free_bufs(&mq->mqrq[i]);
+}
+
+/**
+ * mmc_init_queue - initialise a queue structure.
+ * @mq: mmc queue
+ * @card: mmc card to attach this queue
+ * @lock: queue lock
+ * @subname: partition subname
+ *
+ * Initialise a MMC card request queue.
+ */
+int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
+		   spinlock_t *lock, const char *subname)
+{
+	struct mmc_host *host = card->host;
+	u64 limit = BLK_BOUNCE_HIGH;
+	bool bounce = false;
+	int ret = -ENOMEM;
+
+	if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
+		limit = (u64)dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT;
+
+	mq->card = card;
+	mq->queue = blk_init_queue(mmc_request_fn, lock);
+	if (!mq->queue)
+		return -ENOMEM;
+
+	mq->qdepth = 2;
+	mq->mqrq = kcalloc(mq->qdepth, sizeof(struct mmc_queue_req),
+			   GFP_KERNEL);
+	if (!mq->mqrq)
+		goto blk_cleanup;
+	mq->mqrq_cur = &mq->mqrq[0];
+	mq->mqrq_prev = &mq->mqrq[1];
+	mq->queue->queuedata = mq;
+
+	blk_queue_prep_rq(mq->queue, mmc_prep_request);
+	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
+	queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, mq->queue);
+	if (mmc_can_erase(card))
+		mmc_queue_setup_discard(mq->queue, card);
+
+#ifdef CONFIG_MMC_BLOCK_BOUNCE
+	if (host->max_segs == 1) {
+		unsigned int bouncesz;
+
+		bouncesz = MMC_QUEUE_BOUNCESZ;
+
+		if (bouncesz > host->max_req_size)
+			bouncesz = host->max_req_size;
+		if (bouncesz > host->max_seg_size)
+			bouncesz = host->max_seg_size;
+		if (bouncesz > (host->max_blk_count * 512))
+			bouncesz = host->max_blk_count * 512;
+
+		if (bouncesz > 512 &&
+		    mmc_queue_alloc_bounce_bufs(mq, bouncesz)) {
+			blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
+			blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
+			blk_queue_max_segments(mq->queue, bouncesz / 512);
+			blk_queue_max_segment_size(mq->queue, bouncesz);
+
+			ret = mmc_queue_alloc_bounce_sgs(mq, bouncesz);
+			if (ret)
+				goto cleanup_queue;
+			bounce = true;
+		}
+	}
+#endif
+
+	if (!bounce) {
+		blk_queue_bounce_limit(mq->queue, limit);
+		blk_queue_max_hw_sectors(mq->queue,
+			min(host->max_blk_count, host->max_req_size / 512));
+		blk_queue_max_segments(mq->queue, host->max_segs);
+		blk_queue_max_segment_size(mq->queue, host->max_seg_size);
+
+		ret = mmc_queue_alloc_sgs(mq, host->max_segs);
+		if (ret)
+			goto cleanup_queue;
+	}
+
+	sema_init(&mq->thread_sem, 1);
+
+	mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
+		host->index, subname ? subname : "");
+
+	if (IS_ERR(mq->thread)) {
+		ret = PTR_ERR(mq->thread);
+		goto cleanup_queue;
+	}
+
+	return 0;
+
+ cleanup_queue:
+	mmc_queue_reqs_free_bufs(mq);
+	kfree(mq->mqrq);
+	mq->mqrq = NULL;
+blk_cleanup:
+	blk_cleanup_queue(mq->queue);
+	return ret;
+}
+
+void mmc_cleanup_queue(struct mmc_queue *mq)
+{
+	struct request_queue *q = mq->queue;
+	unsigned long flags;
+
+	/* Make sure the queue isn't suspended, as that will deadlock */
+	mmc_queue_resume(mq);
+
+	/* Then terminate our worker thread */
+	kthread_stop(mq->thread);
+
+	/* Empty the queue */
+	spin_lock_irqsave(q->queue_lock, flags);
+	q->queuedata = NULL;
+	blk_start_queue(q);
+	spin_unlock_irqrestore(q->queue_lock, flags);
+
+	mmc_queue_reqs_free_bufs(mq);
+	kfree(mq->mqrq);
+	mq->mqrq = NULL;
+
+	mq->card = NULL;
+}
+EXPORT_SYMBOL(mmc_cleanup_queue);
+
+/**
+ * mmc_queue_suspend - suspend a MMC request queue
+ * @mq: MMC queue to suspend
+ *
+ * Stop the block request queue, and wait for our thread to
+ * complete any outstanding requests.  This ensures that we
+ * won't suspend while a request is being processed.
+ */
+void mmc_queue_suspend(struct mmc_queue *mq)
+{
+	struct request_queue *q = mq->queue;
+	unsigned long flags;
+
+	if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
+		mq->flags |= MMC_QUEUE_SUSPENDED;
+
+		spin_lock_irqsave(q->queue_lock, flags);
+		blk_stop_queue(q);
+		spin_unlock_irqrestore(q->queue_lock, flags);
+
+		down(&mq->thread_sem);
+	}
+}
+
+/**
+ * mmc_queue_resume - resume a previously suspended MMC request queue
+ * @mq: MMC queue to resume
+ */
+void mmc_queue_resume(struct mmc_queue *mq)
+{
+	struct request_queue *q = mq->queue;
+	unsigned long flags;
+
+	if (mq->flags & MMC_QUEUE_SUSPENDED) {
+		mq->flags &= ~MMC_QUEUE_SUSPENDED;
+
+		up(&mq->thread_sem);
+
+		spin_lock_irqsave(q->queue_lock, flags);
+		blk_start_queue(q);
+		spin_unlock_irqrestore(q->queue_lock, flags);
+	}
+}
+
+/*
+ * Prepare the sg list(s) to be handed of to the host driver
+ */
+unsigned int mmc_queue_map_sg(struct mmc_queue *mq, struct mmc_queue_req *mqrq)
+{
+	unsigned int sg_len;
+	size_t buflen;
+	struct scatterlist *sg;
+	int i;
+
+	if (!mqrq->bounce_buf)
+		return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);
+
+	sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);
+
+	mqrq->bounce_sg_len = sg_len;
+
+	buflen = 0;
+	for_each_sg(mqrq->bounce_sg, sg, sg_len, i)
+		buflen += sg->length;
+
+	sg_init_one(mqrq->sg, mqrq->bounce_buf, buflen);
+
+	return 1;
+}
+
+/*
+ * If writing, bounce the data to the buffer before the request
+ * is sent to the host driver
+ */
+void mmc_queue_bounce_pre(struct mmc_queue_req *mqrq)
+{
+	if (!mqrq->bounce_buf)
+		return;
+
+	if (rq_data_dir(mqrq->req) != WRITE)
+		return;
+
+	sg_copy_to_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
+		mqrq->bounce_buf, mqrq->sg[0].length);
+}
+
+/*
+ * If reading, bounce the data from the buffer after the request
+ * has been handled by the host driver
+ */
+void mmc_queue_bounce_post(struct mmc_queue_req *mqrq)
+{
+	if (!mqrq->bounce_buf)
+		return;
+
+	if (rq_data_dir(mqrq->req) != READ)
+		return;
+
+	sg_copy_from_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
+		mqrq->bounce_buf, mqrq->sg[0].length);
+}

drivers/mmc/core/queue.h

@@ -0,0 +1,64 @@
+#ifndef MMC_QUEUE_H
+#define MMC_QUEUE_H
+
+static inline bool mmc_req_is_special(struct request *req)
+{
+	return req &&
+		(req_op(req) == REQ_OP_FLUSH ||
+		 req_op(req) == REQ_OP_DISCARD ||
+		 req_op(req) == REQ_OP_SECURE_ERASE);
+}
+
+struct request;
+struct task_struct;
+struct mmc_blk_data;
+
+struct mmc_blk_request {
+	struct mmc_request	mrq;
+	struct mmc_command	sbc;
+	struct mmc_command	cmd;
+	struct mmc_command	stop;
+	struct mmc_data		data;
+	int			retune_retry_done;
+};
+
+struct mmc_queue_req {
+	struct request		*req;
+	struct mmc_blk_request	brq;
+	struct scatterlist	*sg;
+	char			*bounce_buf;
+	struct scatterlist	*bounce_sg;
+	unsigned int		bounce_sg_len;
+	struct mmc_async_req	mmc_active;
+};
+
+struct mmc_queue {
+	struct mmc_card		*card;
+	struct task_struct	*thread;
+	struct semaphore	thread_sem;
+	unsigned int		flags;
+#define MMC_QUEUE_SUSPENDED	(1 << 0)
+#define MMC_QUEUE_NEW_REQUEST	(1 << 1)
+	bool			asleep;
+	struct mmc_blk_data	*blkdata;
+	struct request_queue	*queue;
+	struct mmc_queue_req	*mqrq;
+	struct mmc_queue_req	*mqrq_cur;
+	struct mmc_queue_req	*mqrq_prev;
+	int			qdepth;
+};
+
+extern int mmc_init_queue(struct mmc_queue *, struct mmc_card *, spinlock_t *,
+			  const char *);
+extern void mmc_cleanup_queue(struct mmc_queue *);
+extern void mmc_queue_suspend(struct mmc_queue *);
+extern void mmc_queue_resume(struct mmc_queue *);
+
+extern unsigned int mmc_queue_map_sg(struct mmc_queue *,
+				     struct mmc_queue_req *);
+extern void mmc_queue_bounce_pre(struct mmc_queue_req *);
+extern void mmc_queue_bounce_post(struct mmc_queue_req *);
+
+extern int mmc_access_rpmb(struct mmc_queue *);
+
+#endif