2 files changed, 213 insertions, 120 deletions

diff --git a/drivers/dma/shdma.c b/drivers/dma/shdma.c
index 8d9acd7..9546f5f 100644
--- a/drivers/dma/shdma.c
+++ b/drivers/dma/shdma.c
@@ -23,16 +23,19 @@
 #include <linux/dmaengine.h>
 #include <linux/delay.h>
 #include <linux/dma-mapping.h>
-#include <linux/dmapool.h>
 #include <linux/platform_device.h>
 #include <cpu/dma.h>
 #include <asm/dma-sh.h>
 #include "shdma.h"
 
 /* DMA descriptor control */
-#define DESC_LAST	(-1)
-#define DESC_COMP	(1)
-#define DESC_NCOMP	(0)
+enum sh_dmae_desc_status {
+	DESC_IDLE,
+	DESC_PREPARED,
+	DESC_SUBMITTED,
+	DESC_COMPLETED,	/* completed, have to call callback */
+	DESC_WAITING,	/* callback called, waiting for ack / re-submit */
+};
 
 #define NR_DESCS_PER_CHANNEL 32
 /*
@@ -45,6 +48,8 @@
  */
 #define RS_DEFAULT  (RS_DUAL)
 
+static void sh_dmae_chan_ld_cleanup(struct sh_dmae_chan *sh_chan, bool all);
+
 #define SH_DMAC_CHAN_BASE(id) (dma_base_addr[id])
 static void sh_dmae_writel(struct sh_dmae_chan *sh_dc, u32 data, u32 reg)
 {
@@ -106,11 +111,11 @@ static inline unsigned int calc_xmit_shift(struct sh_dmae_chan *sh_chan)
 	return ts_shift[(chcr & CHCR_TS_MASK) >> CHCR_TS_SHIFT];
 }
 
-static void dmae_set_reg(struct sh_dmae_chan *sh_chan, struct sh_dmae_regs hw)
+static void dmae_set_reg(struct sh_dmae_chan *sh_chan, struct sh_dmae_regs *hw)
 {
-	sh_dmae_writel(sh_chan, hw.sar, SAR);
-	sh_dmae_writel(sh_chan, hw.dar, DAR);
-	sh_dmae_writel(sh_chan, hw.tcr >> calc_xmit_shift(sh_chan), TCR);
+	sh_dmae_writel(sh_chan, hw->sar, SAR);
+	sh_dmae_writel(sh_chan, hw->dar, DAR);
+	sh_dmae_writel(sh_chan, hw->tcr >> calc_xmit_shift(sh_chan), TCR);
 }
 
 static void dmae_start(struct sh_dmae_chan *sh_chan)
@@ -184,8 +189,9 @@ static int dmae_set_dmars(struct sh_dmae_chan *sh_chan, u16 val)
 
 static dma_cookie_t sh_dmae_tx_submit(struct dma_async_tx_descriptor *tx)
 {
-	struct sh_desc *desc = tx_to_sh_desc(tx);
+	struct sh_desc *desc = tx_to_sh_desc(tx), *chunk, *last = desc, *c;
 	struct sh_dmae_chan *sh_chan = to_sh_chan(tx->chan);
+	dma_async_tx_callback callback = tx->callback;
 	dma_cookie_t cookie;
 
 	spin_lock_bh(&sh_chan->desc_lock);
@@ -195,45 +201,53 @@ static dma_cookie_t sh_dmae_tx_submit(struct dma_async_tx_descriptor *tx)
 	if (cookie < 0)
 		cookie = 1;
 
-	/* If desc only in the case of 1 */
-	if (desc->async_tx.cookie != -EBUSY)
-		desc->async_tx.cookie = cookie;
-	sh_chan->common.cookie = desc->async_tx.cookie;
+	sh_chan->common.cookie = cookie;
+	tx->cookie = cookie;
+
+	/* Mark all chunks of this descriptor as submitted, move to the queue */
+	list_for_each_entry_safe(chunk, c, desc->node.prev, node) {
+		/*
+		 * All chunks are on the global ld_free, so, we have to find
+		 * the end of the chain ourselves
+		 */
+		if (chunk != desc && (chunk->mark == DESC_IDLE ||
+				      chunk->async_tx.cookie > 0 ||
+				      chunk->async_tx.cookie == -EBUSY ||
+				      &chunk->node == &sh_chan->ld_free))
+			break;
+		chunk->mark = DESC_SUBMITTED;
+		/* Callback goes to the last chunk */
+		chunk->async_tx.callback = NULL;
+		chunk->cookie = cookie;
+		list_move_tail(&chunk->node, &sh_chan->ld_queue);
+		last = chunk;
+	}
+
+	last->async_tx.callback = callback;
+	last->async_tx.callback_param = tx->callback_param;
 
-	list_splice_init(&desc->tx_list, sh_chan->ld_queue.prev);
+	dev_dbg(sh_chan->dev, "submit #%d@%p on %d: %x[%d] -> %x\n",
+		tx->cookie, &last->async_tx, sh_chan->id,
+		desc->hw.sar, desc->hw.tcr, desc->hw.dar);
 
 	spin_unlock_bh(&sh_chan->desc_lock);
 
 	return cookie;
 }
 
+/* Called with desc_lock held */
 static struct sh_desc *sh_dmae_get_desc(struct sh_dmae_chan *sh_chan)
 {
-	struct sh_desc *desc, *_desc, *ret = NULL;
+	struct sh_desc *desc;
 
-	spin_lock_bh(&sh_chan->desc_lock);
-	list_for_each_entry_safe(desc, _desc, &sh_chan->ld_free, node) {
-		if (async_tx_test_ack(&desc->async_tx)) {
+	list_for_each_entry(desc, &sh_chan->ld_free, node)
+		if (desc->mark != DESC_PREPARED) {
+			BUG_ON(desc->mark != DESC_IDLE);
 			list_del(&desc->node);
-			ret = desc;
-			break;
+			return desc;
 		}
-	}
-	spin_unlock_bh(&sh_chan->desc_lock);
-
-	return ret;
-}
-
-static void sh_dmae_put_desc(struct sh_dmae_chan *sh_chan, struct sh_desc *desc)
-{
-	if (desc) {
-		spin_lock_bh(&sh_chan->desc_lock);
-
-		list_splice_init(&desc->tx_list, &sh_chan->ld_free);
-		list_add(&desc->node, &sh_chan->ld_free);
 
-		spin_unlock_bh(&sh_chan->desc_lock);
-	}
+	return NULL;
 }
 
 static int sh_dmae_alloc_chan_resources(struct dma_chan *chan)
@@ -252,11 +266,10 @@ static int sh_dmae_alloc_chan_resources(struct dma_chan *chan)
 		dma_async_tx_descriptor_init(&desc->async_tx,
 					&sh_chan->common);
 		desc->async_tx.tx_submit = sh_dmae_tx_submit;
-		desc->async_tx.flags = DMA_CTRL_ACK;
-		INIT_LIST_HEAD(&desc->tx_list);
-		sh_dmae_put_desc(sh_chan, desc);
+		desc->mark = DESC_IDLE;
 
 		spin_lock_bh(&sh_chan->desc_lock);
+		list_add(&desc->node, &sh_chan->ld_free);
 		sh_chan->descs_allocated++;
 	}
 	spin_unlock_bh(&sh_chan->desc_lock);
@@ -273,7 +286,10 @@ static void sh_dmae_free_chan_resources(struct dma_chan *chan)
 	struct sh_desc *desc, *_desc;
 	LIST_HEAD(list);
 
-	BUG_ON(!list_empty(&sh_chan->ld_queue));
+	/* Prepared and not submitted descriptors can still be on the queue */
+	if (!list_empty(&sh_chan->ld_queue))
+		sh_dmae_chan_ld_cleanup(sh_chan, true);
+
 	spin_lock_bh(&sh_chan->desc_lock);
 
 	list_splice_init(&sh_chan->ld_free, &list);
@@ -292,6 +308,8 @@ static struct dma_async_tx_descriptor *sh_dmae_prep_memcpy(
 	struct sh_dmae_chan *sh_chan;
 	struct sh_desc *first = NULL, *prev = NULL, *new;
 	size_t copy_size;
+	LIST_HEAD(tx_list);
+	int chunks = (len + SH_DMA_TCR_MAX) / (SH_DMA_TCR_MAX + 1);
 
 	if (!chan)
 		return NULL;
@@ -301,108 +319,189 @@ static struct dma_async_tx_descriptor *sh_dmae_prep_memcpy(
 
 	sh_chan = to_sh_chan(chan);
 
+	/* Have to lock the whole loop to protect against concurrent release */
+	spin_lock_bh(&sh_chan->desc_lock);
+
+	/*
+	 * Chaining:
+	 * first descriptor is what user is dealing with in all API calls, its
+	 *	cookie is at first set to -EBUSY, at tx-submit to a positive
+	 *	number
+	 * if more than one chunk is needed further chunks have cookie = -EINVAL
+	 * the last chunk, if not equal to the first, has cookie = -ENOSPC
+	 * all chunks are linked onto the tx_list head with their .node heads
+	 *	only during this function, then they are immediately spliced
+	 *	back onto the free list in form of a chain
+	 */
 	do {
-		/* Allocate the link descriptor from DMA pool */
+		/* Allocate the link descriptor from the free list */
 		new = sh_dmae_get_desc(sh_chan);
 		if (!new) {
 			dev_err(sh_chan->dev,
 				"No free memory for link descriptor\n");
-			goto err_get_desc;
+			list_for_each_entry(new, &tx_list, node)
+				new->mark = DESC_IDLE;
+			list_splice(&tx_list, &sh_chan->ld_free);
+			spin_unlock_bh(&sh_chan->desc_lock);
+			return NULL;
 		}
 
-		copy_size = min(len, (size_t)SH_DMA_TCR_MAX);
+		copy_size = min(len, (size_t)SH_DMA_TCR_MAX + 1);
 
 		new->hw.sar = dma_src;
 		new->hw.dar = dma_dest;
 		new->hw.tcr = copy_size;
-		if (!first)
+		if (!first) {
+			/* First desc */
+			new->async_tx.cookie = -EBUSY;
 			first = new;
+		} else {
+			/* Other desc - invisible to the user */
+			new->async_tx.cookie = -EINVAL;
+		}
 
-		new->mark = DESC_NCOMP;
-		async_tx_ack(&new->async_tx);
+		dev_dbg(sh_chan->dev,
+			"chaining %u of %u with %p, dst %x, cookie %d\n",
+			copy_size, len, &new->async_tx, dma_dest,
+			new->async_tx.cookie);
+
+		new->mark = DESC_PREPARED;
+		new->async_tx.flags = flags;
+		new->chunks = chunks--;
 
 		prev = new;
 		len -= copy_size;
 		dma_src += copy_size;
 		dma_dest += copy_size;
 		/* Insert the link descriptor to the LD ring */
-		list_add_tail(&new->node, &first->tx_list);
+		list_add_tail(&new->node, &tx_list);
 	} while (len);
 
-	new->async_tx.flags = flags; /* client is in control of this ack */
-	new->async_tx.cookie = -EBUSY; /* Last desc */
+	if (new != first)
+		new->async_tx.cookie = -ENOSPC;
 
-	return &first->async_tx;
+	/* Put them back on the free list, so, they don't get lost */
+	list_splice_tail(&tx_list, &sh_chan->ld_free);
 
-err_get_desc:
-	sh_dmae_put_desc(sh_chan, first);
-	return NULL;
+	spin_unlock_bh(&sh_chan->desc_lock);
 
+	return &first->async_tx;
 }
 
-/*
- * sh_chan_ld_cleanup - Clean up link descriptors
- *
- * This function clean up the ld_queue of DMA channel.
- */
-static void sh_dmae_chan_ld_cleanup(struct sh_dmae_chan *sh_chan)
+static dma_async_tx_callback __ld_cleanup(struct sh_dmae_chan *sh_chan, bool all)
 {
 	struct sh_desc *desc, *_desc;
+	/* Is the "exposed" head of a chain acked? */
+	bool head_acked = false;
+	dma_cookie_t cookie = 0;
+	dma_async_tx_callback callback = NULL;
+	void *param = NULL;
 
 	spin_lock_bh(&sh_chan->desc_lock);
 	list_for_each_entry_safe(desc, _desc, &sh_chan->ld_queue, node) {
-		dma_async_tx_callback callback;
-		void *callback_param;
-
-		/* non send data */
-		if (desc->mark == DESC_NCOMP)
+		struct dma_async_tx_descriptor *tx = &desc->async_tx;
+
+		BUG_ON(tx->cookie > 0 && tx->cookie != desc->cookie);
+		BUG_ON(desc->mark != DESC_SUBMITTED &&
+		       desc->mark != DESC_COMPLETED &&
+		       desc->mark != DESC_WAITING);
+
+		/*
+		 * queue is ordered, and we use this loop to (1) clean up all
+		 * completed descriptors, and to (2) update descriptor flags of
+		 * any chunks in a (partially) completed chain
+		 */
+		if (!all && desc->mark == DESC_SUBMITTED &&
+		    desc->cookie != cookie)
 			break;
 
-		/* send data sesc */
-		callback = desc->async_tx.callback;
-		callback_param = desc->async_tx.callback_param;
+		if (tx->cookie > 0)
+			cookie = tx->cookie;
 
-		/* Remove from ld_queue list */
-		list_splice_init(&desc->tx_list, &sh_chan->ld_free);
+		if (desc->mark == DESC_COMPLETED && desc->chunks == 1) {
+			BUG_ON(sh_chan->completed_cookie != desc->cookie - 1);
+			sh_chan->completed_cookie = desc->cookie;
+		}
 
-		dev_dbg(sh_chan->dev, "link descriptor %p will be recycle.\n",
-				desc);
+		/* Call callback on the last chunk */
+		if (desc->mark == DESC_COMPLETED && tx->callback) {
+			desc->mark = DESC_WAITING;
+			callback = tx->callback;
+			param = tx->callback_param;
+			dev_dbg(sh_chan->dev, "descriptor #%d@%p on %d callback\n",
+				tx->cookie, tx, sh_chan->id);
+			BUG_ON(desc->chunks != 1);
+			break;
+		}
 
-		list_move(&desc->node, &sh_chan->ld_free);
-		/* Run the link descriptor callback function */
-		if (callback) {
-			spin_unlock_bh(&sh_chan->desc_lock);
-			dev_dbg(sh_chan->dev, "link descriptor %p callback\n",
-					desc);
-			callback(callback_param);
-			spin_lock_bh(&sh_chan->desc_lock);
+		if (tx->cookie > 0 || tx->cookie == -EBUSY) {
+			if (desc->mark == DESC_COMPLETED) {
+				BUG_ON(tx->cookie < 0);
+				desc->mark = DESC_WAITING;
+			}
+			head_acked = async_tx_test_ack(tx);
+		} else {
+			switch (desc->mark) {
+			case DESC_COMPLETED:
+				desc->mark = DESC_WAITING;
+				/* Fall through */
+			case DESC_WAITING:
+				if (head_acked)
+					async_tx_ack(&desc->async_tx);
+			}
+		}
+
+		dev_dbg(sh_chan->dev, "descriptor %p #%d completed.\n",
+			tx, tx->cookie);
+
+		if (((desc->mark == DESC_COMPLETED ||
+		      desc->mark == DESC_WAITING) &&
+		     async_tx_test_ack(&desc->async_tx)) || all) {
+			/* Remove from ld_queue list */
+			desc->mark = DESC_IDLE;
+			list_move(&desc->node, &sh_chan->ld_free);
 		}
 	}
 	spin_unlock_bh(&sh_chan->desc_lock);
+
+	if (callback)
+		callback(param);
+
+	return callback;
+}
+
+/*
+ * sh_chan_ld_cleanup - Clean up link descriptors
+ *
+ * This function cleans up the ld_queue of DMA channel.
+ */
+static void sh_dmae_chan_ld_cleanup(struct sh_dmae_chan *sh_chan, bool all)
+{
+	while (__ld_cleanup(sh_chan, all))
+		;
 }
 
 static void sh_chan_xfer_ld_queue(struct sh_dmae_chan *sh_chan)
 {
-	struct list_head *ld_node;
-	struct sh_dmae_regs hw;
+	struct sh_desc *sd;
 
+	spin_lock_bh(&sh_chan->desc_lock);
 	/* DMA work check */
-	if (dmae_is_busy(sh_chan))
+	if (dmae_is_busy(sh_chan)) {
+		spin_unlock_bh(&sh_chan->desc_lock);
 		return;
+	}
 
 	/* Find the first un-transfer desciptor */
-	for (ld_node = sh_chan->ld_queue.next;
-		(ld_node != &sh_chan->ld_queue)
-			&& (to_sh_desc(ld_node)->mark == DESC_COMP);
-		ld_node = ld_node->next)
-		cpu_relax();
-
-	if (ld_node != &sh_chan->ld_queue) {
-		/* Get the ld start address from ld_queue */
-		hw = to_sh_desc(ld_node)->hw;
-		dmae_set_reg(sh_chan, hw);
-		dmae_start(sh_chan);
-	}
+	list_for_each_entry(sd, &sh_chan->ld_queue, node)
+		if (sd->mark == DESC_SUBMITTED) {
+			/* Get the ld start address from ld_queue */
+			dmae_set_reg(sh_chan, &sd->hw);
+			dmae_start(sh_chan);
+			break;
+		}
+
+	spin_unlock_bh(&sh_chan->desc_lock);
 }
 
 static void sh_dmae_memcpy_issue_pending(struct dma_chan *chan)
@@ -420,12 +519,11 @@ static enum dma_status sh_dmae_is_complete(struct dma_chan *chan,
 	dma_cookie_t last_used;
 	dma_cookie_t last_complete;
 
-	sh_dmae_chan_ld_cleanup(sh_chan);
+	sh_dmae_chan_ld_cleanup(sh_chan, false);
 
 	last_used = chan->cookie;
 	last_complete = sh_chan->completed_cookie;
-	if (last_complete == -EBUSY)
-		last_complete = last_used;
+	BUG_ON(last_complete < 0);
 
 	if (done)
 		*done = last_complete;
@@ -480,11 +578,13 @@ static irqreturn_t sh_dmae_err(int irq, void *data)
 		err = sh_dmae_rst(0);
 		if (err)
 			return err;
+#ifdef SH_DMAC_BASE1
 		if (shdev->pdata.mode & SHDMA_DMAOR1) {
 			err = sh_dmae_rst(1);
 			if (err)
 				return err;
 		}
+#endif
 		disable_irq(irq);
 		return IRQ_HANDLED;
 	}
@@ -494,35 +594,25 @@ static irqreturn_t sh_dmae_err(int irq, void *data)
 static void dmae_do_tasklet(unsigned long data)
 {
 	struct sh_dmae_chan *sh_chan = (struct sh_dmae_chan *)data;
-	struct sh_desc *desc, *_desc, *cur_desc = NULL;
+	struct sh_desc *desc;
 	u32 sar_buf = sh_dmae_readl(sh_chan, SAR);
 
-	list_for_each_entry_safe(desc, _desc,
-				 &sh_chan->ld_queue, node) {
-		if ((desc->hw.sar + desc->hw.tcr) == sar_buf) {
-			cur_desc = desc;
+	spin_lock(&sh_chan->desc_lock);
+	list_for_each_entry(desc, &sh_chan->ld_queue, node) {
+		if ((desc->hw.sar + desc->hw.tcr) == sar_buf &&
+		    desc->mark == DESC_SUBMITTED) {
+			dev_dbg(sh_chan->dev, "done #%d@%p dst %u\n",
+				desc->async_tx.cookie, &desc->async_tx,
+				desc->hw.dar);
+			desc->mark = DESC_COMPLETED;
 			break;
 		}
 	}
+	spin_unlock(&sh_chan->desc_lock);
 
-	if (cur_desc) {
-		switch (cur_desc->async_tx.cookie) {
-		case 0: /* other desc data */
-			break;
-		case -EBUSY: /* last desc */
-		sh_chan->completed_cookie =
-				cur_desc->async_tx.cookie;
-			break;
-		default: /* first desc ( 0 < )*/
-			sh_chan->completed_cookie =
-				cur_desc->async_tx.cookie - 1;
-			break;
-		}
-		cur_desc->mark = DESC_COMP;
-	}
 	/* Next desc */
 	sh_chan_xfer_ld_queue(sh_chan);
-	sh_dmae_chan_ld_cleanup(sh_chan);
+	sh_dmae_chan_ld_cleanup(sh_chan, false);
 }
 
 static unsigned int get_dmae_irq(unsigned int id)
diff --git a/drivers/dma/shdma.h b/drivers/dma/shdma.h
index 60b81e5..108f1cf 100644
--- a/drivers/dma/shdma.h
+++ b/drivers/dma/shdma.h
@@ -13,9 +13,9 @@
 #ifndef __DMA_SHDMA_H
 #define __DMA_SHDMA_H
 
-#include <linux/device.h>
-#include <linux/dmapool.h>
 #include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
 
 #define SH_DMA_TCR_MAX 0x00FFFFFF	/* 16MB */
 
@@ -26,13 +26,16 @@ struct sh_dmae_regs {
 };
 
 struct sh_desc {
-	struct list_head tx_list;
 	struct sh_dmae_regs hw;
 	struct list_head node;
 	struct dma_async_tx_descriptor async_tx;
+	dma_cookie_t cookie;
+	int chunks;
 	int mark;
 };
 
+struct device;
+
 struct sh_dmae_chan {
 	dma_cookie_t completed_cookie;	/* The maximum cookie completed */
 	spinlock_t desc_lock;		/* Descriptor operation lock */