Merge tag 'iio-for-4.4a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio...

[firefly-linux-kernel-4.4.55.git] / drivers / dma / tegra20-apb-dma.c

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 53a8075dcec80f470f42304d93c68aa94963cc5c..c8f79dcaaee8089c1a031c2e76fbbda2c4465488 100644 (file)
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -219,6 +219,13 @@ struct tegra_dma {
        void __iomem                    *base_addr;
        const struct tegra_dma_chip_data *chip_data;
 
+       /*
+        * Counter for managing global pausing of the DMA controller.
+        * Only applicable for devices that don't support individual
+        * channel pausing.
+        */
+       u32                             global_pause_count;
+
        /* Some register need to be cache before suspend */
        u32                             reg_gen;
 
@@ -358,16 +365,32 @@ static void tegra_dma_global_pause(struct tegra_dma_channel *tdc,
        struct tegra_dma *tdma = tdc->tdma;
 
        spin_lock(&tdma->global_lock);
-       tdma_write(tdma, TEGRA_APBDMA_GENERAL, 0);
-       if (wait_for_burst_complete)
-               udelay(TEGRA_APBDMA_BURST_COMPLETE_TIME);
+
+       if (tdc->tdma->global_pause_count == 0) {
+               tdma_write(tdma, TEGRA_APBDMA_GENERAL, 0);
+               if (wait_for_burst_complete)
+                       udelay(TEGRA_APBDMA_BURST_COMPLETE_TIME);
+       }
+
+       tdc->tdma->global_pause_count++;
+
+       spin_unlock(&tdma->global_lock);
 }
 
 static void tegra_dma_global_resume(struct tegra_dma_channel *tdc)
 {
        struct tegra_dma *tdma = tdc->tdma;
 
-       tdma_write(tdma, TEGRA_APBDMA_GENERAL, TEGRA_APBDMA_GENERAL_ENABLE);
+       spin_lock(&tdma->global_lock);
+
+       if (WARN_ON(tdc->tdma->global_pause_count == 0))
+               goto out;
+
+       if (--tdc->tdma->global_pause_count == 0)
+               tdma_write(tdma, TEGRA_APBDMA_GENERAL,
+                          TEGRA_APBDMA_GENERAL_ENABLE);
+
+out:
        spin_unlock(&tdma->global_lock);
 }
 
@@ -1407,6 +1430,7 @@ static int tegra_dma_probe(struct platform_device *pdev)
        dma_cap_set(DMA_PRIVATE, tdma->dma_dev.cap_mask);
        dma_cap_set(DMA_CYCLIC, tdma->dma_dev.cap_mask);
 
+       tdma->global_pause_count = 0;
        tdma->dma_dev.dev = &pdev->dev;
        tdma->dma_dev.device_alloc_chan_resources =
                                        tegra_dma_alloc_chan_resources;