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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: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Magnus Damm 2011-05-24 10:31:12 +00:00 committed by Paul Mundt
parent 66ad12931d
commit 26fc02ab55
1 changed files with 8 additions and 3 deletions
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11
drivers/dma/shdma.c
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@ -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