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Message-ID: <Pine.LNX.4.64.1108181650530.5245@axis700.grange>
Date: Thu, 18 Aug 2011 16:55:27 +0200 (CEST)
From: Guennadi Liakhovetski <g.liakhovetski@....de>
To: linux-kernel@...r.kernel.org
cc: linux-sh@...r.kernel.org, Vinod Koul <vinod.koul@...el.com>,
Dan Williams <dan.j.williams@...el.com>,
Paul Mundt <lethal@...ux-sh.org>
Subject: [PATCH] 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 <g.liakhovetski@....de>
---
tested on mackerel (sh7372) with dmatest, sh_mobile_sdhi and sh_mmcif with
runtime PM and STR.
drivers/dma/shdma.c | 94 +++++++++++++++++++++++++++++++++++++--------------
drivers/dma/shdma.h | 7 ++++
2 files changed, 75 insertions(+), 26 deletions(-)
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 {
--
1.7.2.5
--
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