dmaengine: tegra-apb: Improve DMA synchronization (6697255f) · Commits · 戴 / test

drivers/dma/tegra20-apb-dma.c

+25 −0

Original line number	Diff line number	Diff line
		@@ -24,6 +24,7 @@
		#include <linux/pm_runtime.h>
		#include <linux/reset.h>
		#include <linux/slab.h>
		#include <linux/wait.h>

		#include "dmaengine.h"

		@@ -202,6 +203,8 @@ struct tegra_dma_channel {
		unsigned int slave_id;
		struct dma_slave_config dma_sconfig;
		struct tegra_dma_channel_regs channel_reg;

		struct wait_queue_head wq;
		};

		/* tegra_dma: Tegra DMA specific information */
		@@ -680,6 +683,7 @@ static irqreturn_t tegra_dma_isr(int irq, void *dev_id)
		tdc_write(tdc, TEGRA_APBDMA_CHAN_STATUS, status);
		tdc->isr_handler(tdc, false);
		tasklet_schedule(&tdc->tasklet);
		wake_up_all(&tdc->wq);
		spin_unlock(&tdc->lock);
		return IRQ_HANDLED;
		}
		@@ -785,6 +789,7 @@ static int tegra_dma_terminate_all(struct dma_chan *dc)
		tegra_dma_resume(tdc);

		pm_runtime_put(tdc->tdma->dev);
		wake_up_all(&tdc->wq);

		skip_dma_stop:
		tegra_dma_abort_all(tdc);
		@@ -800,10 +805,29 @@ skip_dma_stop:
		return 0;
		}

		static bool tegra_dma_eoc_interrupt_deasserted(struct tegra_dma_channel *tdc)
		{
		unsigned long flags;
		u32 status;

		spin_lock_irqsave(&tdc->lock, flags);
		status = tdc_read(tdc, TEGRA_APBDMA_CHAN_STATUS);
		spin_unlock_irqrestore(&tdc->lock, flags);

		return !(status & TEGRA_APBDMA_STATUS_ISE_EOC);
		}

		static void tegra_dma_synchronize(struct dma_chan *dc)
		{
		struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);

		/*
		* CPU, which handles interrupt, could be busy in
		* uninterruptible state, in this case sibling CPU
		* should wait until interrupt is handled.
		*/
		wait_event(tdc->wq, tegra_dma_eoc_interrupt_deasserted(tdc));

		tasklet_kill(&tdc->tasklet);
		}

		@@ -1498,6 +1522,7 @@ static int tegra_dma_probe(struct platform_device *pdev)
		tasklet_init(&tdc->tasklet, tegra_dma_tasklet,
		(unsigned long)tdc);
		spin_lock_init(&tdc->lock);
		init_waitqueue_head(&tdc->wq);

		INIT_LIST_HEAD(&tdc->pending_sg_req);
		INIT_LIST_HEAD(&tdc->free_sg_req);

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