diff options
| author |   Ian Abbott <abbotti@mev.co.uk> | 2019-04-26 14:54:13 +0100 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-04-27 15:00:35 +0200 |
| commit | a4965d98b4d1ffa5b22f2039bc9e87898aff4976 (patch) | |
| tree | 7b32dcae872200090020519a48c75eb9e36c0c45 | |
| parent | LS1021A: dtsi: add ftm quad decoder entries (diff) | |
| download | linux-dev-a4965d98b4d1ffa5b22f2039bc9e87898aff4976.tar.xz linux-dev-a4965d98b4d1ffa5b22f2039bc9e87898aff4976.zip | |
staging: comedi: comedi_isadma: Use a non-NULL device for DMA API
The "comedi_isadma" module calls `dma_alloc_coherent()` and
`dma_free_coherent()` with a NULL device pointer which is no longer
allowed. If the `hw_dev` member of the `struct comedi_device` has been
set to a valid device, that can be used instead. Unfortunately, all the
current users of the "comedi_isadma" module leave the `hw_dev` member
set to NULL. In that case, fall back to using the comedi "class" device
pointed to by the `class_dev` member if that is non-NULL. In that case,
make it "DMA-capable" with a coherent DMA mask set to the ISA bus limit
of 16MB (24 bits).
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/staging/comedi/drivers/comedi_isadma.c | 17 | ||||
| -rw-r--r-- | drivers/staging/comedi/drivers/comedi_isadma.h | 3 |
2 files changed, 18 insertions, 2 deletions
diff --git a/drivers/staging/comedi/drivers/comedi_isadma.c b/drivers/staging/comedi/drivers/comedi_isadma.c index b77dc8d5d3ff..c729094298c2 100644 --- a/drivers/staging/comedi/drivers/comedi_isadma.c +++ b/drivers/staging/comedi/drivers/comedi_isadma.c @@ -172,6 +172,19 @@ struct comedi_isadma *comedi_isadma_alloc(struct comedi_device *dev, goto no_dma; dma->desc = desc; dma->n_desc = n_desc; + if (dev->hw_dev) { + dma->dev = dev->hw_dev; + } else { + /* Fall back to using the "class" device. */ + if (!dev->class_dev) + goto no_dma; + /* Need 24-bit mask for ISA DMA. */ + if (dma_coerce_mask_and_coherent(dev->class_dev, + DMA_BIT_MASK(24))) { + goto no_dma; + } + dma->dev = dev->class_dev; + } dma_chans[0] = dma_chan1; if (dma_chan2 == 0 || dma_chan2 == dma_chan1) @@ -192,7 +205,7 @@ struct comedi_isadma *comedi_isadma_alloc(struct comedi_device *dev, desc = &dma->desc[i]; desc->chan = dma_chans[i]; desc->maxsize = maxsize; - desc->virt_addr = dma_alloc_coherent(NULL, desc->maxsize, + desc->virt_addr = dma_alloc_coherent(dma->dev, desc->maxsize, &desc->hw_addr, GFP_KERNEL); if (!desc->virt_addr) @@ -224,7 +237,7 @@ void comedi_isadma_free(struct comedi_isadma *dma) for (i = 0; i < dma->n_desc; i++) { desc = &dma->desc[i]; if (desc->virt_addr) - dma_free_coherent(NULL, desc->maxsize, + dma_free_coherent(dma->dev, desc->maxsize, desc->virt_addr, desc->hw_addr); } diff --git a/drivers/staging/comedi/drivers/comedi_isadma.h b/drivers/staging/comedi/drivers/comedi_isadma.h index 2bd1329d727f..9d2b12db7e6e 100644 --- a/drivers/staging/comedi/drivers/comedi_isadma.h +++ b/drivers/staging/comedi/drivers/comedi_isadma.h @@ -10,6 +10,7 @@ #include <linux/types.h> struct comedi_device; +struct device; /* * These are used to avoid issues when <asm/dma.h> and the DMA_MODE_ @@ -38,6 +39,7 @@ struct comedi_isadma_desc { /** * struct comedi_isadma - ISA DMA data + * @dev: device to allocate non-coherent memory for * @desc: cookie for each DMA buffer * @n_desc: the number of cookies * @cur_dma: the current cookie in use @@ -45,6 +47,7 @@ struct comedi_isadma_desc { * @chan2: the second DMA channel requested */ struct comedi_isadma { + struct device *dev; struct comedi_isadma_desc *desc; int n_desc; int cur_dma; |