Messages in this thread | | | Date | Mon, 5 Feb 2024 17:55:03 +0000 | Subject | Re: [PATCH 04/12] bcm2835-dma: Advertise the full DMA range | From | Robin Murphy <> |
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On 2024-02-04 6:59 am, Andrea della Porta wrote: > From: Phil Elwell <phil@raspberrypi.com> > > Unless the DMA mask is set wider than 32 bits, DMA mapping will use a > bounce buffer. > > Signed-off-by: Phil Elwell <phil@raspberrypi.com> > --- > drivers/dma/bcm2835-dma.c | 18 +++++++++++++++--- > 1 file changed, 15 insertions(+), 3 deletions(-) > > diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c > index 36bad198b655..237dcdb8d726 100644 > --- a/drivers/dma/bcm2835-dma.c > +++ b/drivers/dma/bcm2835-dma.c > @@ -39,6 +39,7 @@ > #define BCM2711_DMA_MEMCPY_CHAN 14 > > struct bcm2835_dma_cfg_data { > + u64 dma_mask; > u32 chan_40bit_mask; > }; > > @@ -308,10 +309,12 @@ DEFINE_SPINLOCK(memcpy_lock); > > static const struct bcm2835_dma_cfg_data bcm2835_dma_cfg = { > .chan_40bit_mask = 0, > + .dma_mask = DMA_BIT_MASK(32), > }; > > static const struct bcm2835_dma_cfg_data bcm2711_dma_cfg = { > .chan_40bit_mask = BIT(11) | BIT(12) | BIT(13) | BIT(14), > + .dma_mask = DMA_BIT_MASK(36), > }; > > static inline size_t bcm2835_dma_max_frame_length(struct bcm2835_chan *c) > @@ -1263,6 +1266,8 @@ static struct dma_chan *bcm2835_dma_xlate(struct of_phandle_args *spec, > > static int bcm2835_dma_probe(struct platform_device *pdev) > { > + const struct bcm2835_dma_cfg_data *cfg_data; > + const struct of_device_id *of_id; > struct bcm2835_dmadev *od; > struct resource *res; > void __iomem *base; > @@ -1272,13 +1277,20 @@ static int bcm2835_dma_probe(struct platform_device *pdev) > int irq_flags; > uint32_t chans_available; > char chan_name[BCM2835_DMA_CHAN_NAME_SIZE]; > - const struct of_device_id *of_id; > int chan_count, chan_start, chan_end; > > + of_id = of_match_node(bcm2835_dma_of_match, pdev->dev.of_node); > + if (!of_id) { > + dev_err(&pdev->dev, "Failed to match compatible string\n"); > + return -EINVAL; > + } > + > + cfg_data = of_id->data;
We've had of_device_get_match_data() for nearly 9 years now, and even a generic device_get_match_data() for 6 ;)
> + > if (!pdev->dev.dma_mask) > pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
[ Passing nit: that also really shouldn't be there, especially since cdfee5623290 ]
> > - rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)); > + rc = dma_set_mask_and_coherent(&pdev->dev, cfg_data->dma_mask);
Wait, does chan_40bit_mask mean that you still have some channels which *can't* address this full mask? If so this can't work properly. You may well need to redesign a bit further to have a separate DMA device for each channel such they can each have different masks.
Thanks, Robin.
> if (rc) { > dev_err(&pdev->dev, "Unable to set DMA mask\n"); > return rc; > @@ -1342,7 +1354,7 @@ static int bcm2835_dma_probe(struct platform_device *pdev) > return -EINVAL; > } > > - od->cfg_data = of_id->data; > + od->cfg_data = cfg_data; > > /* Request DMA channel mask from device tree */ > if (of_property_read_u32(pdev->dev.of_node,
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