From 7a1cd9ad87979744e1510782b25c38feb9602739 Mon Sep 17 00:00:00 2001 From: Guennadi Liakhovetski Date: Thu, 18 Aug 2011 16:55:27 +0200 Subject: 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: Guennadi Liakhovetski Signed-off-by: Vinod Koul diff --git a/drivers/dma/shdma.c b/drivers/dma/shdma.c index e7bb747..81809c2 100644 --- a/drivers/dma/shdma.c +++ b/drivers/dma/shdma.c @@ -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); - sh_chan_xfer_ld_queue(sh_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; diff --git a/drivers/dma/shdma.h b/drivers/dma/shdma.h index dc56576..2b55a27 100644 --- a/drivers/dma/shdma.h +++ b/drivers/dma/shdma.h @@ -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 { -- cgit v0.10.2