| Message ID | 20220218205557.486208-4-benjamin.walker@intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | dmaengine: memset clarifications and fixes | expand |
On 2/18/2022 1:55 PM, Ben Walker wrote: > The value passed in to .prep_dma_memset is to be treated as a single > byte repeating pattern. > > Signed-off-by: Ben Walker <benjamin.walker@intel.com> > Cc: Ludovic Desroches <ludovic.desroches@microchip.com> > Cc: Tudor Ambarus <tudor.ambarus@microchip.com> > --- > drivers/dma/at_xdmac.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c > index a1da2b4b6d732..547778fc6445b 100644 > --- a/drivers/dma/at_xdmac.c > +++ b/drivers/dma/at_xdmac.c > @@ -1202,6 +1202,7 @@ static struct at_xdmac_desc *at_xdmac_memset_create_desc(struct dma_chan *chan, > unsigned long flags; > size_t ublen; > u32 dwidth; > + unsigned char pattern; > /* > * WARNING: The channel configuration is set here since there is no > * dmaengine_slave_config call in this case. Moreover we don't know the > @@ -1244,10 +1245,16 @@ static struct at_xdmac_desc *at_xdmac_memset_create_desc(struct dma_chan *chan, > > chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth); > > + /* Only the first byte of value is to be used according to dmaengine */ > + pattern = (unsigned char)value; I need to change this to signed as well. > + > ublen = len >> dwidth; > > desc->lld.mbr_da = dst_addr; > - desc->lld.mbr_ds = value; > + desc->lld.mbr_ds = (pattern << 24) | > + (pattern << 16) | > + (pattern << 8) | > + pattern; > desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV3 > | AT_XDMAC_MBR_UBC_NDEN > | AT_XDMAC_MBR_UBC_NSEN
diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c index a1da2b4b6d732..547778fc6445b 100644 --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -1202,6 +1202,7 @@ static struct at_xdmac_desc *at_xdmac_memset_create_desc(struct dma_chan *chan, unsigned long flags; size_t ublen; u32 dwidth; + unsigned char pattern; /* * WARNING: The channel configuration is set here since there is no * dmaengine_slave_config call in this case. Moreover we don't know the @@ -1244,10 +1245,16 @@ static struct at_xdmac_desc *at_xdmac_memset_create_desc(struct dma_chan *chan, chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth); + /* Only the first byte of value is to be used according to dmaengine */ + pattern = (unsigned char)value; + ublen = len >> dwidth; desc->lld.mbr_da = dst_addr; - desc->lld.mbr_ds = value; + desc->lld.mbr_ds = (pattern << 24) | + (pattern << 16) | + (pattern << 8) | + pattern; desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV3 | AT_XDMAC_MBR_UBC_NDEN | AT_XDMAC_MBR_UBC_NSEN
The value passed in to .prep_dma_memset is to be treated as a single byte repeating pattern. Signed-off-by: Ben Walker <benjamin.walker@intel.com> Cc: Ludovic Desroches <ludovic.desroches@microchip.com> Cc: Tudor Ambarus <tudor.ambarus@microchip.com> --- drivers/dma/at_xdmac.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)