[PATCH] OMAP: PM: DMA: Enable runtime pm

G, Manjunath Kondaiah
2011-01-24T09:21:13Z

From: Manjunath G Kondaiah <manjugk@ti.com>

Enable runtime pm and use pm_runtime_get_sync and pm_runtime_put
for OMAP DMA driver.

Since DMA driver callback will happen from interrupt context and
DMA client driver will release all DMA resources from interrupt
context itself, pm_runtime_put_sync() cannot be used in DMA driver.
Instead, pm_runtime_put() is used which is asynchronous call and
gets executed in work queue.

Boot tested on OMAP4 blaze and all applicable tests are executed
along with dma hwmod series.

Signed-off-by: G, Manjunath Kondaiah <manjugk@ti.com>
---
Discussion and alignment for using runtime API's in DMA can be accessed at:
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg37819.html
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg38355.html
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg38391.html
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg38400.html

arch/arm/plat-omap/dma.c | 18 +++++++++++++++++-
1 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
index c4b2b47..48ee292 100644
--- a/arch/arm/plat-omap/dma.c
+++ b/arch/arm/plat-omap/dma.c
@@ -35,6 +35,7 @@
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/delay.h>
+#include <linux/pm_runtime.h>

#include <asm/system.h>
#include <mach/hardware.h>
@@ -58,6 +59,7 @@ enum { DMA_CHAIN_STARTED, DMA_CHAIN_NOTSTARTED };
#define OMAP_FUNC_MUX_ARM_BASE (0xfffe1000 + 0xec)

static struct omap_system_dma_plat_info *p;
+static struct platform_device *pd;
static struct omap_dma_dev_attr *d;

static int enable_1510_mode;
@@ -676,6 +678,7 @@ int omap_request_dma(int dev_id, const char *dev_name,
unsigned long flags;
struct omap_dma_lch *chan;

+ pm_runtime_get_sync(&pd->dev);
spin_lock_irqsave(&dma_chan_lock, flags);
for (ch = 0; ch < dma_chan_count; ch++) {
if (free_ch == -1 && dma_chan[ch].dev_id == -1) {
@@ -686,6 +689,7 @@ int omap_request_dma(int dev_id, const char *dev_name,
}
if (free_ch == -1) {
spin_unlock_irqrestore(&dma_chan_lock, flags);
+ pm_runtime_put(&pd->dev);
return -EBUSY;
}
chan = dma_chan + free_ch;
@@ -779,7 +783,7 @@ void omap_free_dma(int lch)
p->dma_write(0, CCR, lch);
omap_clear_dma(lch);
}
-
+ pm_runtime_put(&pd->dev);
spin_lock_irqsave(&dma_chan_lock, flags);
dma_chan[lch].dev_id = -1;
dma_chan[lch].next_lch = -1;
@@ -1979,6 +1983,7 @@ static int __devinit omap_system_dma_probe(struct platform_device *pdev)
return -EINVAL;
}

+ pd = pdev;
d = p->dma_attr;
errata = p->errata;

@@ -2000,6 +2005,9 @@ static int __devinit omap_system_dma_probe(struct platform_device *pdev)
}
}

+ pm_runtime_enable(&pd->dev);
+ pm_runtime_get_sync(&pd->dev);
+
spin_lock_init(&dma_chan_lock);
for (ch = 0; ch < dma_chan_count; ch++) {
omap_clear_dma(ch);
@@ -2065,6 +2073,14 @@ static int __devinit omap_system_dma_probe(struct platform_device *pdev)
dma_chan[1].dev_id = 1;
}
p->show_dma_caps();
+
+ /*
+ * Note: If dma channels are reserved through boot paramters,
+ * then dma device is always enabled.
+ */
+ if (!omap_dma_reserve_channels)
+ pm_runtime_put(&pd->dev);
+
return 0;

exit_dma_irq_fail:
--
1.7.1