dmaengine: shdma: add runtime- and system-level power management

This patch extends and fixes runtime power management in the shdma
driver to support powering down the DMA controller and adds support
for system-level suspend and resume.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

2 files changed, 69 insertions, 0 deletions

diff --git a/drivers/dma/shdma.c b/drivers/dma/shdma.c
index 727f51e903d9..00b5f320b0e8 100644
--- a/drivers/dma/shdma.c
+++ b/drivers/dma/shdma.c
@@ -1255,6 +1255,8 @@ rst_err:
         spin_unlock_irqrestore(&sh_dmae_lock, flags);
 
         pm_runtime_put(&pdev->dev);
+        pm_runtime_disable(&pdev->dev);
+
         if (dmars)
                 iounmap(shdev->dmars);
 emapdmars:
@@ -1313,12 +1315,78 @@ static void sh_dmae_shutdown(struct platform_device *pdev)
         sh_dmae_ctl_stop(shdev);
 }
 
+static int sh_dmae_runtime_suspend(struct device *dev)
+{
+        return 0;
+}
+
+static int sh_dmae_runtime_resume(struct device *dev)
+{
+        struct sh_dmae_device *shdev = dev_get_drvdata(dev);
+
+        return sh_dmae_rst(shdev);
+}
+
+#ifdef CONFIG_PM
+static int sh_dmae_suspend(struct device *dev)
+{
+        struct sh_dmae_device *shdev = dev_get_drvdata(dev);
+        int i;
+
+        for (i = 0; i < shdev->pdata->channel_num; i++) {
+                struct sh_dmae_chan *sh_chan = shdev->chan[i];
+                if (sh_chan->descs_allocated)
+                        sh_chan->pm_error = pm_runtime_put_sync(dev);
+        }
+
+        return 0;
+}
+
+static int sh_dmae_resume(struct device *dev)
+{
+        struct sh_dmae_device *shdev = dev_get_drvdata(dev);
+        int i;
+
+        for (i = 0; i < shdev->pdata->channel_num; i++) {
+                struct sh_dmae_chan *sh_chan = shdev->chan[i];
+                struct sh_dmae_slave *param = sh_chan->common.private;
+
+                if (!sh_chan->descs_allocated)
+                        continue;
+
+                if (!sh_chan->pm_error)
+                        pm_runtime_get_sync(dev);
+
+                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);
+                }
+        }
+
+        return 0;
+}
+#else
+#define sh_dmae_suspend NULL
+#define sh_dmae_resume NULL
+#endif
+
+const struct dev_pm_ops sh_dmae_pm = {
+        .suspend                = sh_dmae_suspend,
+        .resume                 = sh_dmae_resume,
+        .runtime_suspend        = sh_dmae_runtime_suspend,
+        .runtime_resume         = sh_dmae_runtime_resume,
+};
+
 static struct platform_driver sh_dmae_driver = {
         .remove         = __exit_p(sh_dmae_remove),
         .shutdown       = sh_dmae_shutdown,
         .driver = {
                 .owner  = THIS_MODULE,
                 .name   = "sh-dma-engine",
+                .pm     = &sh_dmae_pm,
         },
 };
 
diff --git a/drivers/dma/shdma.h b/drivers/dma/shdma.h
index 52e4fb173805..3f9d3cd06584 100644
--- a/drivers/dma/shdma.h
+++ b/drivers/dma/shdma.h
@@ -37,6 +37,7 @@ struct sh_dmae_chan {
         int id;                         /* Raw id of this channel */
         u32 __iomem *base;
         char dev_id[16];                /* unique name per DMAC of channel */
+        int pm_error;
 };
 
 struct sh_dmae_device {