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Commit 26fc02ab authored by Magnus Damm's avatar Magnus Damm Committed by Paul Mundt
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dmaengine: shdma: Make second memory window optional 



This patch makes the shdma.c driver allow slave operation
on DMA hardware mapped with a single I/O-memory window.

The dmae_set_dmars() function is adjusted to use the
first memory window in case of a missing DMARS window.

At probe() time the code is updated to enable DMA_SLAVE
only if slave information is passed with the platform data.

Signed-off-by: default avatarMagnus Damm <damm@opensource.se>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 66ad1293

drivers/dma/shdma.c

+8 −3
Original line number Diff line number Diff line
@@ -213,12 +213,17 @@ static int dmae_set_dmars(struct sh_dmae_chan *sh_chan, u16 val) 
						struct sh_dmae_device, common);

	struct sh_dmae_pdata *pdata = shdev->pdata;

	const struct sh_dmae_channel *chan_pdata = &pdata->channel[sh_chan->id];

	u16 __iomem *addr = shdev->dmars + chan_pdata->dmars / sizeof(u16);

	u16 __iomem *addr = shdev->dmars;

	int shift = chan_pdata->dmars_bit;



	if (dmae_is_busy(sh_chan))

		return -EBUSY;



	/* in the case of a missing DMARS resource use first memory window */

	if (!addr)

		addr = (u16 __iomem *)shdev->chan_reg;

	addr += chan_pdata->dmars / sizeof(u16);



	__raw_writew((__raw_readw(addr) & (0xff00 >> shift)) | (val << shift),

		     addr);
@@ -1087,7 +1092,7 @@ static int __init sh_dmae_probe(struct platform_device *pdev) 
		return -ENODEV;



	chan = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	/* DMARS area is optional, if absent, this controller cannot do slave DMA */

	/* DMARS area is optional */

	dmars = platform_get_resource(pdev, IORESOURCE_MEM, 1);

	/*

	 * IRQ resources:
@@ -1154,7 +1159,7 @@ static int __init sh_dmae_probe(struct platform_device *pdev) 
	INIT_LIST_HEAD(&shdev->common.channels);



	dma_cap_set(DMA_MEMCPY, shdev->common.cap_mask);

	if (dmars)

	if (pdata->slave && pdata->slave_num)

		dma_cap_set(DMA_SLAVE, shdev->common.cap_mask);



	shdev->common.device_alloc_chan_resources