[PATCH v2] OMAP: PM: DMA: Enable runtime pm

[G, Manjunath Kondaiah]

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

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

The DMA driver uses auto suspend feature of runtime pm framework through
which the clock gets disabled automatically if there is no activity for
more than one second.

Testing:
Compile: omap1_defconfig and omap2plus_defconfig
Boot: OMAP1710(H3), OMAP2420(H4), OMAP3630(Zoom3), OMAP4(Blaze)

On zoom3 core retention is tested with following steps:
echo 1 > /debug/pm_debug/sleep_while_idle
echo 1 > /debug/pm_debug/enable_off_mode
echo 5 > /sys/devices/platform/omap/omap_uart.0/sleep_timeout
echo 5 > /sys/devices/platform/omap/omap_uart.1/sleep_timeout
echo 5 > /sys/devices/platform/omap/omap_uart.2/sleep_timeout
echo 5 > /sys/devices/platform/omap/omap_uart.3/sleep_timeout

It is observed that(on pm branch), core retention count gets increasing if the
board is left idle for more than 5 seconds. However, it doesnot enter off mode
(even without DMA runtime changes).

Signed-off-by: G, Manjunath Kondaiah <manjugk at ti.com>
---
 arch/arm/plat-omap/dma.c |   27 +++++++++++++++++++++++++++
 1 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
index 2ec3b5d..6bfe25c 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>
@@ -59,6 +60,7 @@ enum { DMA_CHAIN_STARTED, DMA_CHAIN_NOTSTARTED };
 
 static struct omap_system_dma_plat_info *p;
 static struct omap_dma_dev_attr *d;
+static struct device *dev;
 
 static int enable_1510_mode;
 static u32 errata;
@@ -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(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_autosuspend(dev);
 		return -EBUSY;
 	}
 	chan = dma_chan + free_ch;
@@ -743,6 +747,7 @@ int omap_request_dma(int dev_id, const char *dev_name,
 	}
 
 	*dma_ch_out = free_ch;
+	pm_runtime_put_autosuspend(dev);
 
 	return 0;
 }
@@ -871,6 +876,8 @@ void omap_start_dma(int lch)
 {
 	u32 l;
 
+	pm_runtime_get_sync(dev);
+
 	/*
 	 * The CPC/CDAC register needs to be initialized to zero
 	 * before starting dma transfer.
@@ -1805,6 +1812,8 @@ static int omap1_dma_handle_ch(int ch)
 	if (likely(dma_chan[ch].callback != NULL))
 		dma_chan[ch].callback(ch, csr, dma_chan[ch].data);
 
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
 	return 1;
 }
 
@@ -1899,6 +1908,8 @@ static int omap2_dma_handle_ch(int ch)
 	if (likely(dma_chan[ch].callback != NULL))
 		dma_chan[ch].callback(ch, status, dma_chan[ch].data);
 
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
 	return 0;
 }
 
@@ -1978,6 +1989,7 @@ static int __devinit omap_system_dma_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	dev			= &pdev->dev;
 	d			= p->dma_attr;
 	errata			= p->errata;
 
@@ -1999,6 +2011,11 @@ static int __devinit omap_system_dma_probe(struct platform_device *pdev)
 		}
 	}
 
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_set_autosuspend_delay(dev, 1000);
+	pm_runtime_enable(dev);
+	pm_runtime_get_sync(dev);
+
 	spin_lock_init(&dma_chan_lock);
 	for (ch = 0; ch < dma_chan_count; ch++) {
 		omap_clear_dma(ch);
@@ -2064,6 +2081,16 @@ 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_get(dev);
+
+	pm_runtime_put_autosuspend(dev);
+
 	return 0;
 
 exit_dma_irq_fail:
-- 
1.7.1