| Message ID | 20240524182702.1317935-10-dave.stevenson@raspberrypi.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | BCM2835 DMA mapping cleanups and fixes | expand |
On Fri, May 24, 2024 at 07:26:53PM +0100, Dave Stevenson wrote: > The code handling DMA mapping is currently incorrect and > needs a sequence of fixups. Can you descript what incorrect here? > Move the mapping out into a separate function and structure > to allow for those fixes to be applied more cleanly. > > Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com> > --- > drivers/dma/bcm2835-dma.c | 46 ++++++++++++++++++++++++++++++++------- > 1 file changed, 38 insertions(+), 8 deletions(-) > > diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c > index aefaa1f01d7f..ef1d95bae84e 100644 > --- a/drivers/dma/bcm2835-dma.c > +++ b/drivers/dma/bcm2835-dma.c > @@ -65,6 +65,10 @@ struct bcm2835_cb_entry { > dma_addr_t paddr; > }; > > +struct bcm2835_dma_chan_map { > + dma_addr_t addr; > +}; > + > struct bcm2835_chan { > struct virt_dma_chan vc; > > @@ -74,6 +78,7 @@ struct bcm2835_chan { > int ch; > struct bcm2835_desc *desc; > struct dma_pool *cb_pool; > + struct bcm2835_dma_chan_map map; I suppose map should in bcm2835_desc. if put in chan, how about client driver create two desc by bcm2835_dma_prep_slave_sg()? prep_slave_sg() submit() prep_savle_sg() submit() issue_pending() Frank > > void __iomem *chan_base; > int irq_number; > @@ -268,6 +273,19 @@ static inline bool need_dst_incr(enum dma_transfer_direction direction) > } > > return false; > +}; > + > +static int bcm2835_dma_map_slave_addr(struct dma_chan *chan, > + phys_addr_t dev_addr, > + size_t dev_size, > + enum dma_data_direction dev_dir) > +{ > + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); > + struct bcm2835_dma_chan_map *map = &c->map; > + > + map->addr = dev_addr; > + > + return 0; > } > > static void bcm2835_dma_free_cb_chain(struct bcm2835_desc *desc) > @@ -734,13 +752,19 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_slave_sg( > } > > if (direction == DMA_DEV_TO_MEM) { > - if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) > + if (bcm2835_dma_map_slave_addr(chan, c->cfg.src_addr, > + c->cfg.src_addr_width, > + DMA_TO_DEVICE)) > return NULL; > - src = c->cfg.src_addr; > + > + src = c->map.addr; > } else { > - if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) > + if (bcm2835_dma_map_slave_addr(chan, c->cfg.dst_addr, > + c->cfg.dst_addr_width, > + DMA_FROM_DEVICE)) > return NULL; > - dst = c->cfg.dst_addr; > + > + dst = c->map.addr; > } > > /* count frames in sg list */ > @@ -795,14 +819,20 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic( > __func__, buf_len, period_len); > > if (direction == DMA_DEV_TO_MEM) { > - if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) > + if (bcm2835_dma_map_slave_addr(chan, c->cfg.src_addr, > + c->cfg.src_addr_width, > + DMA_TO_DEVICE)) > return NULL; > - src = c->cfg.src_addr; > + > + src = c->map.addr; > dst = buf_addr; > } else { > - if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) > + if (bcm2835_dma_map_slave_addr(chan, c->cfg.dst_addr, > + c->cfg.dst_addr_width, > + DMA_FROM_DEVICE)) > return NULL; > - dst = c->cfg.dst_addr; > + > + dst = c->map.addr; > src = buf_addr; > } > > -- > 2.34.1 >
diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c index aefaa1f01d7f..ef1d95bae84e 100644 --- a/drivers/dma/bcm2835-dma.c +++ b/drivers/dma/bcm2835-dma.c @@ -65,6 +65,10 @@ struct bcm2835_cb_entry { dma_addr_t paddr; }; +struct bcm2835_dma_chan_map { + dma_addr_t addr; +}; + struct bcm2835_chan { struct virt_dma_chan vc; @@ -74,6 +78,7 @@ struct bcm2835_chan { int ch; struct bcm2835_desc *desc; struct dma_pool *cb_pool; + struct bcm2835_dma_chan_map map; void __iomem *chan_base; int irq_number; @@ -268,6 +273,19 @@ static inline bool need_dst_incr(enum dma_transfer_direction direction) } return false; +}; + +static int bcm2835_dma_map_slave_addr(struct dma_chan *chan, + phys_addr_t dev_addr, + size_t dev_size, + enum dma_data_direction dev_dir) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + struct bcm2835_dma_chan_map *map = &c->map; + + map->addr = dev_addr; + + return 0; } static void bcm2835_dma_free_cb_chain(struct bcm2835_desc *desc) @@ -734,13 +752,19 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_slave_sg( } if (direction == DMA_DEV_TO_MEM) { - if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) + if (bcm2835_dma_map_slave_addr(chan, c->cfg.src_addr, + c->cfg.src_addr_width, + DMA_TO_DEVICE)) return NULL; - src = c->cfg.src_addr; + + src = c->map.addr; } else { - if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) + if (bcm2835_dma_map_slave_addr(chan, c->cfg.dst_addr, + c->cfg.dst_addr_width, + DMA_FROM_DEVICE)) return NULL; - dst = c->cfg.dst_addr; + + dst = c->map.addr; } /* count frames in sg list */ @@ -795,14 +819,20 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic( __func__, buf_len, period_len); if (direction == DMA_DEV_TO_MEM) { - if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) + if (bcm2835_dma_map_slave_addr(chan, c->cfg.src_addr, + c->cfg.src_addr_width, + DMA_TO_DEVICE)) return NULL; - src = c->cfg.src_addr; + + src = c->map.addr; dst = buf_addr; } else { - if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) + if (bcm2835_dma_map_slave_addr(chan, c->cfg.dst_addr, + c->cfg.dst_addr_width, + DMA_FROM_DEVICE)) return NULL; - dst = c->cfg.dst_addr; + + dst = c->map.addr; src = buf_addr; }
The code handling DMA mapping is currently incorrect and needs a sequence of fixups. Move the mapping out into a separate function and structure to allow for those fixes to be applied more cleanly. Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com> --- drivers/dma/bcm2835-dma.c | 46 ++++++++++++++++++++++++++++++++------- 1 file changed, 38 insertions(+), 8 deletions(-)