Commit f8122a82 authored by Andy Shevchenko's avatar Andy Shevchenko Committed by Vinod Koul
Browse files

dw_dmac: allocate dma descriptors from DMA_COHERENT memory 



Currently descriptors are allocated from normal cacheable memory and that slows
down filling the descriptors, as we need to call cache_coherency routines
afterwards. It would be better to allocate memory for these descriptors from
DMA_COHERENT memory. This would make code much cleaner too.

Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent 855372c0

drivers/dma/dw_dmac.c

+17 −64
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/delay.h>

#include <linux/dmaengine.h>

#include <linux/dma-mapping.h>

#include <linux/dmapool.h>

#include <linux/init.h>

#include <linux/interrupt.h>

#include <linux/io.h>
@@ -91,14 +92,6 @@ static inline unsigned int dwc_get_data_width(struct dma_chan *chan, int master) 


/*----------------------------------------------------------------------*/



/*

 * Because we're not relying on writeback from the controller (it may not

 * even be configured into the core!) we don't need to use dma_pool.  These

 * descriptors -- and associated data -- are cacheable.  We do need to make

 * sure their dcache entries are written back before handing them off to

 * the controller, though.

 */



static struct device *chan2dev(struct dma_chan *chan)

{

	return &chan->dev->device;
@@ -137,19 +130,6 @@ static struct dw_desc *dwc_desc_get(struct dw_dma_chan *dwc) 
	return ret;

}



static void dwc_sync_desc_for_cpu(struct dw_dma_chan *dwc, struct dw_desc *desc)

{

	struct dw_desc	*child;



	list_for_each_entry(child, &desc->tx_list, desc_node)

		dma_sync_single_for_cpu(chan2parent(&dwc->chan),

				child->txd.phys, sizeof(child->lli),

				DMA_TO_DEVICE);

	dma_sync_single_for_cpu(chan2parent(&dwc->chan),

			desc->txd.phys, sizeof(desc->lli),

			DMA_TO_DEVICE);

}



/*

 * Move a descriptor, including any children, to the free list.

 * `desc' must not be on any lists.
@@ -161,8 +141,6 @@ static void dwc_desc_put(struct dw_dma_chan *dwc, struct dw_desc *desc) 
	if (desc) {

		struct dw_desc *child;



		dwc_sync_desc_for_cpu(dwc, desc);



		spin_lock_irqsave(&dwc->lock, flags);

		list_for_each_entry(child, &desc->tx_list, desc_node)

			dev_vdbg(chan2dev(&dwc->chan),
@@ -335,8 +313,6 @@ dwc_descriptor_complete(struct dw_dma_chan *dwc, struct dw_desc *desc, 
		param = txd->callback_param;

	}



	dwc_sync_desc_for_cpu(dwc, desc);



	/* async_tx_ack */

	list_for_each_entry(child, &desc->tx_list, desc_node)

		async_tx_ack(&child->txd);
@@ -770,25 +746,17 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, 
			first = desc;

		} else {

			prev->lli.llp = desc->txd.phys;

			dma_sync_single_for_device(chan2parent(chan),

					prev->txd.phys, sizeof(prev->lli),

					DMA_TO_DEVICE);

			list_add_tail(&desc->desc_node,

					&first->tx_list);

		}

		prev = desc;

	}





	if (flags & DMA_PREP_INTERRUPT)

		/* Trigger interrupt after last block */

		prev->lli.ctllo |= DWC_CTLL_INT_EN;



	prev->lli.llp = 0;

	dma_sync_single_for_device(chan2parent(chan),

			prev->txd.phys, sizeof(prev->lli),

			DMA_TO_DEVICE);



	first->txd.flags = flags;

	first->len = len;
@@ -876,10 +844,6 @@ slave_sg_todev_fill_desc: 
				first = desc;

			} else {

				prev->lli.llp = desc->txd.phys;

				dma_sync_single_for_device(chan2parent(chan),

						prev->txd.phys,

						sizeof(prev->lli),

						DMA_TO_DEVICE);

				list_add_tail(&desc->desc_node,

						&first->tx_list);

			}
@@ -938,10 +902,6 @@ slave_sg_fromdev_fill_desc: 
				first = desc;

			} else {

				prev->lli.llp = desc->txd.phys;

				dma_sync_single_for_device(chan2parent(chan),

						prev->txd.phys,

						sizeof(prev->lli),

						DMA_TO_DEVICE);

				list_add_tail(&desc->desc_node,

						&first->tx_list);

			}
@@ -961,10 +921,6 @@ slave_sg_fromdev_fill_desc: 
		prev->lli.ctllo |= DWC_CTLL_INT_EN;



	prev->lli.llp = 0;

	dma_sync_single_for_device(chan2parent(chan),

			prev->txd.phys, sizeof(prev->lli),

			DMA_TO_DEVICE);



	first->len = total_len;



	return &first->txd;
@@ -1118,7 +1074,6 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan) 
	struct dw_desc		*desc;

	int			i;

	unsigned long		flags;

	int			ret;



	dev_vdbg(chan2dev(chan), "%s\n", __func__);
@@ -1139,21 +1094,21 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan) 
	spin_lock_irqsave(&dwc->lock, flags);

	i = dwc->descs_allocated;

	while (dwc->descs_allocated < NR_DESCS_PER_CHANNEL) {

		dma_addr_t phys;



		spin_unlock_irqrestore(&dwc->lock, flags);



		desc = kzalloc(sizeof(struct dw_desc), GFP_KERNEL);

		desc = dma_pool_alloc(dw->desc_pool, GFP_ATOMIC, &phys);

		if (!desc)

			goto err_desc_alloc;



		memset(desc, 0, sizeof(struct dw_desc));



		INIT_LIST_HEAD(&desc->tx_list);

		dma_async_tx_descriptor_init(&desc->txd, chan);

		desc->txd.tx_submit = dwc_tx_submit;

		desc->txd.flags = DMA_CTRL_ACK;

		desc->txd.phys = dma_map_single(chan2parent(chan), &desc->lli,

				sizeof(desc->lli), DMA_TO_DEVICE);

		ret = dma_mapping_error(chan2parent(chan), desc->txd.phys);

		if (ret)

			goto err_desc_alloc;

		desc->txd.phys = phys;



		dwc_desc_put(dwc, desc);
@@ -1168,8 +1123,6 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan) 
	return i;



err_desc_alloc:

	kfree(desc);



	dev_info(chan2dev(chan), "only allocated %d descriptors\n", i);



	return i;
@@ -1204,9 +1157,7 @@ static void dwc_free_chan_resources(struct dma_chan *chan) 


	list_for_each_entry_safe(desc, _desc, &list, desc_node) {

		dev_vdbg(chan2dev(chan), "  freeing descriptor %p\n", desc);

		dma_unmap_single(chan2parent(chan), desc->txd.phys,

				sizeof(desc->lli), DMA_TO_DEVICE);

		kfree(desc);

		dma_pool_free(dw->desc_pool, desc, desc->txd.phys);

	}



	dev_vdbg(chan2dev(chan), "%s: done\n", __func__);
@@ -1451,20 +1402,14 @@ struct dw_cyclic_desc *dw_dma_cyclic_prep(struct dma_chan *chan, 
		desc->lli.ctlhi = (period_len >> reg_width);

		cdesc->desc[i] = desc;



		if (last) {

		if (last)

			last->lli.llp = desc->txd.phys;

			dma_sync_single_for_device(chan2parent(chan),

					last->txd.phys, sizeof(last->lli),

					DMA_TO_DEVICE);

		}



		last = desc;

	}



	/* lets make a cyclic list */

	last->lli.llp = cdesc->desc[0]->txd.phys;

	dma_sync_single_for_device(chan2parent(chan), last->txd.phys,

			sizeof(last->lli), DMA_TO_DEVICE);



	dev_dbg(chan2dev(&dwc->chan), "cyclic prepared buf 0x%llx len %zu "

			"period %zu periods %d\n", (unsigned long long)buf_addr,
@@ -1722,6 +1667,14 @@ static int dw_probe(struct platform_device *pdev) 


	platform_set_drvdata(pdev, dw);



	/* create a pool of consistent memory blocks for hardware descriptors */

	dw->desc_pool = dmam_pool_create("dw_dmac_desc_pool", &pdev->dev,

					 sizeof(struct dw_desc), 4, 0);

	if (!dw->desc_pool) {

		dev_err(&pdev->dev, "No memory for descriptors dma pool\n");

		return -ENOMEM;

	}



	tasklet_init(&dw->tasklet, dw_dma_tasklet, (unsigned long)dw);



	INIT_LIST_HEAD(&dw->dma.channels);

drivers/dma/dw_dmac_regs.h

+1 −0
Original line number Diff line number Diff line
@@ -235,6 +235,7 @@ static inline struct dw_dma_chan *to_dw_dma_chan(struct dma_chan *chan) 
struct dw_dma {

	struct dma_device	dma;

	void __iomem		*regs;

	struct dma_pool		*desc_pool;

	struct tasklet_struct	tasklet;

	struct clk		*clk;

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