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Commit 7a1cd9ad authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Vinod Koul
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dma: shdma: transfer based runtime PM 



Currently the shdma dmaengine driver uses runtime PM to save power, when
no channel on the specific controller is requested by a user. This patch
switches the driver to count individual DMA transfers. That way the
controller can be powered down between transfers, even if some of its
channels are in use.

Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: default avatarVinod Koul <vinod.koul@linux.intel.com>
parent b4dae6e1

drivers/dma/shdma.c

+68 −26
Original line number Diff line number Diff line
@@ -259,15 +259,23 @@ static int dmae_set_dmars(struct sh_dmae_chan *sh_chan, u16 val) 
	return 0;

}



static void sh_chan_xfer_ld_queue(struct sh_dmae_chan *sh_chan);



static dma_cookie_t sh_dmae_tx_submit(struct dma_async_tx_descriptor *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);

	struct sh_dmae_slave *param = tx->chan->private;

	dma_async_tx_callback callback = tx->callback;

	dma_cookie_t cookie;

	unsigned long flags;

	bool power_up;



	spin_lock_irqsave(&sh_chan->desc_lock, flags);

	spin_lock_irq(&sh_chan->desc_lock);



	if (list_empty(&sh_chan->ld_queue))

		power_up = true;

	else

		power_up = false;



	cookie = sh_chan->common.cookie;

	cookie++;
@@ -303,7 +311,38 @@ static dma_cookie_t sh_dmae_tx_submit(struct dma_async_tx_descriptor *tx) 
		tx->cookie, &last->async_tx, sh_chan->id,

		desc->hw.sar, desc->hw.tcr, desc->hw.dar);



	spin_unlock_irqrestore(&sh_chan->desc_lock, flags);

	if (power_up) {

		sh_chan->pm_state = DMAE_PM_BUSY;



		pm_runtime_get(sh_chan->dev);



		spin_unlock_irq(&sh_chan->desc_lock);



		pm_runtime_barrier(sh_chan->dev);



		spin_lock_irq(&sh_chan->desc_lock);



		/* Have we been reset, while waiting? */

		if (sh_chan->pm_state != DMAE_PM_ESTABLISHED) {

			dev_dbg(sh_chan->dev, "Bring up channel %d\n",

				sh_chan->id);

			if (param) {

				const struct sh_dmae_slave_config *cfg =

					param->config;



				dmae_set_dmars(sh_chan, cfg->mid_rid);

				dmae_set_chcr(sh_chan, cfg->chcr);

			} else {

				dmae_init(sh_chan);

			}



			if (sh_chan->pm_state == DMAE_PM_PENDING)

				sh_chan_xfer_ld_queue(sh_chan);

			sh_chan->pm_state = DMAE_PM_ESTABLISHED;

		}

	}



	spin_unlock_irq(&sh_chan->desc_lock);



	return cookie;

}
@@ -347,8 +386,6 @@ static int sh_dmae_alloc_chan_resources(struct dma_chan *chan) 
	struct sh_dmae_slave *param = chan->private;

	int ret;



	pm_runtime_get_sync(sh_chan->dev);



	/*

	 * This relies on the guarantee from dmaengine that alloc_chan_resources

	 * never runs concurrently with itself or free_chan_resources.
@@ -368,11 +405,6 @@ static int sh_dmae_alloc_chan_resources(struct dma_chan *chan) 
		}



		param->config = cfg;



		dmae_set_dmars(sh_chan, cfg->mid_rid);

		dmae_set_chcr(sh_chan, cfg->chcr);

	} else {

		dmae_init(sh_chan);

	}



	while (sh_chan->descs_allocated < NR_DESCS_PER_CHANNEL) {
@@ -401,7 +433,6 @@ edescalloc: 
etestused:

efindslave:

	chan->private = NULL;

	pm_runtime_put(sh_chan->dev);

	return ret;

}
@@ -413,7 +444,6 @@ static void sh_dmae_free_chan_resources(struct dma_chan *chan) 
	struct sh_dmae_chan *sh_chan = to_sh_chan(chan);

	struct sh_desc *desc, *_desc;

	LIST_HEAD(list);

	int descs = sh_chan->descs_allocated;



	/* Protect against ISR */

	spin_lock_irq(&sh_chan->desc_lock);
@@ -440,9 +470,6 @@ static void sh_dmae_free_chan_resources(struct dma_chan *chan) 


	spin_unlock_irq(&sh_chan->desc_lock);



	if (descs > 0)

		pm_runtime_put(sh_chan->dev);



	list_for_each_entry_safe(desc, _desc, &list, node)

		kfree(desc);

}
@@ -676,7 +703,6 @@ static int sh_dmae_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, 
						  struct sh_desc, node);

		desc->partial = (desc->hw.tcr - sh_dmae_readl(sh_chan, TCR)) <<

			sh_chan->xmit_shift;



	}

	spin_unlock_irqrestore(&sh_chan->desc_lock, flags);
@@ -761,7 +787,13 @@ static dma_async_tx_callback __ld_cleanup(struct sh_dmae_chan *sh_chan, bool all 
		     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);



			if (list_empty(&sh_chan->ld_queue)) {

				dev_dbg(sh_chan->dev, "Bring down channel %d\n", sh_chan->id);

				pm_runtime_put(sh_chan->dev);

			}

		}

	}
@@ -791,16 +823,14 @@ static void sh_dmae_chan_ld_cleanup(struct sh_dmae_chan *sh_chan, bool all) 
		;

}



/* Called under spin_lock_irq(&sh_chan->desc_lock) */

static void sh_chan_xfer_ld_queue(struct sh_dmae_chan *sh_chan)

{

	struct sh_desc *desc;



	spin_lock_irq(&sh_chan->desc_lock);

	/* DMA work check */

	if (dmae_is_busy(sh_chan)) {

		spin_unlock_irq(&sh_chan->desc_lock);

	if (dmae_is_busy(sh_chan))

		return;

	}



	/* Find the first not transferred descriptor */

	list_for_each_entry(desc, &sh_chan->ld_queue, node)
@@ -813,14 +843,18 @@ static void sh_chan_xfer_ld_queue(struct sh_dmae_chan *sh_chan) 
			dmae_start(sh_chan);

			break;

		}



	spin_unlock_irq(&sh_chan->desc_lock);

}



static void sh_dmae_memcpy_issue_pending(struct dma_chan *chan)

{

	struct sh_dmae_chan *sh_chan = to_sh_chan(chan);



	spin_lock_irq(&sh_chan->desc_lock);

	if (sh_chan->pm_state == DMAE_PM_ESTABLISHED)

		sh_chan_xfer_ld_queue(sh_chan);

	else

		sh_chan->pm_state = DMAE_PM_PENDING;

	spin_unlock_irq(&sh_chan->desc_lock);

}



static enum dma_status sh_dmae_tx_status(struct dma_chan *chan,
@@ -913,6 +947,12 @@ static bool sh_dmae_reset(struct sh_dmae_device *shdev) 


		list_splice_init(&sh_chan->ld_queue, &dl);



		if (!list_empty(&dl)) {

			dev_dbg(sh_chan->dev, "Bring down channel %d\n", sh_chan->id);

			pm_runtime_put(sh_chan->dev);

		}

		sh_chan->pm_state = DMAE_PM_ESTABLISHED;



		spin_unlock(&sh_chan->desc_lock);



		/* Complete all  */
@@ -966,10 +1006,10 @@ static void dmae_do_tasklet(unsigned long data) 
			break;

		}

	}

	spin_unlock_irq(&sh_chan->desc_lock);



	/* Next desc */

	sh_chan_xfer_ld_queue(sh_chan);

	spin_unlock_irq(&sh_chan->desc_lock);



	sh_dmae_chan_ld_cleanup(sh_chan, false);

}
@@ -1037,7 +1077,9 @@ static int __devinit sh_dmae_chan_probe(struct sh_dmae_device *shdev, int id, 
		return -ENOMEM;

	}



	/* copy struct dma_device */

	new_sh_chan->pm_state = DMAE_PM_ESTABLISHED;



	/* reference struct dma_device */

	new_sh_chan->common.device = &shdev->common;



	new_sh_chan->dev = shdev->common.dev;

drivers/dma/shdma.h

+7 −0
Original line number Diff line number Diff line
@@ -23,6 +23,12 @@ 


struct device;



enum dmae_pm_state {

	DMAE_PM_ESTABLISHED,

	DMAE_PM_BUSY,

	DMAE_PM_PENDING,

};



struct sh_dmae_chan {

	dma_cookie_t completed_cookie;	/* The maximum cookie completed */

	spinlock_t desc_lock;		/* Descriptor operation lock */
@@ -38,6 +44,7 @@ struct sh_dmae_chan { 
	u32 __iomem *base;

	char dev_id[16];		/* unique name per DMAC of channel */

	int pm_error;

	enum dmae_pm_state pm_state;

};



struct sh_dmae_device {