[ARM] tegra_i2s_audio: use pm_qos to prevent DMA-callback delays

Signed-off-by: Iliyan Malchev <malchev@google.com>

diff --git a/arch/arm/mach-tegra/tegra_i2s_audio.c b/arch/arm/mach-tegra/tegra_i2s_audio.c
index 0df7ef033fe5c8280092a9a82f02a6032dedaab5..4cbcf98970950e6c93ed07c5a09cb138ede28967 100644 (file)
--- a/arch/arm/mach-tegra/tegra_i2s_audio.c
+++ b/arch/arm/mach-tegra/tegra_i2s_audio.c
@@ -40,6 +40,7 @@
 #include <linux/io.h>
 #include <linux/ktime.h>
 #include <linux/sysfs.h>
+#include <linux/pm_qos_params.h>
 
 #include <linux/tegra_audio.h>
 
@@ -81,6 +82,8 @@ struct audio_stream {
        spinlock_t dma_req_lock; /* guards dma_has_it */
        int dma_has_it;
        struct tegra_dma_req dma_req;
+
+       struct pm_qos_request_list *pm_qos;
 };
 
 struct i2s_pio_stats {
@@ -527,6 +530,8 @@ static int start_playback(struct audio_stream *aos)
        pr_debug("%s: starting playback\n", __func__);
        rc = sound_ops->start_playback(aos);
        spin_unlock_irqrestore(&aos->dma_req_lock, flags);
+       if (!rc)
+               pm_qos_update_request(aos->pm_qos, 0);
        return rc;
 }
 
@@ -542,6 +547,8 @@ static int start_recording_if_necessary(struct audio_stream *ais)
                rc = sound_ops->start_recording(ais);
        }
        spin_unlock_irqrestore(&ais->dma_req_lock, flags);
+       if (!rc)
+               pm_qos_update_request(ais->pm_qos, 0);
        return rc;
 }
 
@@ -554,6 +561,7 @@ static bool stop_playback_if_necessary(struct audio_stream *aos)
                if (aos->active)
                        aos->errors++;
                spin_unlock_irqrestore(&aos->dma_req_lock, flags);
+               pm_qos_update_request(aos->pm_qos, PM_QOS_DEFAULT_VALUE);
                return true;
        }
        spin_unlock_irqrestore(&aos->dma_req_lock, flags);
@@ -582,6 +590,7 @@ static bool stop_recording(struct audio_stream *ais)
        rc = wait_for_completion_interruptible(
                        &ais->stop_completion);
        pr_debug("%s: done: %d\n", __func__, rc);
+       pm_qos_update_request(ais->pm_qos, PM_QOS_DEFAULT_VALUE);
        return true;
 }
 
@@ -2175,6 +2184,24 @@ static int tegra_audio_probe(struct platform_device *pdev)
        if (rc < 0)
                return rc;
 
+       state->in.pm_qos = pm_qos_add_request(PM_QOS_CPU_DMA_LATENCY,
+                               PM_QOS_DEFAULT_VALUE);
+       if (!state->in.pm_qos) {
+               dev_err(&pdev->dev,
+                       "%s: could not register pm_qos handle for input\n",
+                       __func__);
+               return -EIO;
+       }
+
+       state->out.pm_qos = pm_qos_add_request(PM_QOS_CPU_DMA_LATENCY,
+                               PM_QOS_DEFAULT_VALUE);
+       if (!state->out.pm_qos) {
+               dev_err(&pdev->dev,
+                       "%s: could not register pm_qos handle for output\n",
+                       __func__);
+               return -EIO;
+       }
+
        if (request_irq(state->irq, i2s_interrupt,
                        IRQF_DISABLED, state->pdev->name, state) < 0) {
                dev_err(&pdev->dev,