| Message ID | 9486718188ff6ec3d4cb4e196b4caa33c5af48e1.1496434383.git.stillcompiling@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jun 2, 2017 at 3:30 PM, Joshua Clayton <stillcompiling@gmail.com> wrote: Hi Joshua, Thanks for your work on this! Alan > Speed up bit reversal by using hardware bit reversal > Add extra code to handle less than 4byte remnants, if any > > Signed-off-by: Joshua Clayton <stillcompiling@gmail.com> Signed-off-by: Alan Tull <atull@kernel.org> > --- > drivers/fpga/altera-ps-spi.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/fpga/altera-ps-spi.c b/drivers/fpga/altera-ps-spi.c > index 0db8def668ed..14f14efdf0d5 100644 > --- a/drivers/fpga/altera-ps-spi.c > +++ b/drivers/fpga/altera-ps-spi.c > @@ -149,12 +149,23 @@ static int altera_ps_write_init(struct fpga_manager *mgr, > > static void rev_buf(char *buf, size_t len) > { > - const char *fw_end = (buf + len); > + u32 *fw32 = (u32 *)buf; > + size_t extra_bytes = (len & 0x03); > + const u32 *fw_end = (u32 *)(buf + len - extra_bytes); > > /* set buffer to lsb first */ > - while (buf < fw_end) { > - *buf = bitrev8(*buf); > - buf++; > + while (fw32 < fw_end) { > + *fw32 = bitrev8x4(*fw32); > + fw32++; > + } > + > + if (extra_bytes) { > + buf = (char *)fw_end; > + while (extra_bytes) { > + *buf = bitrev8(*buf); > + buf++; > + extra_bytes--; > + } > } > } > > -- > 2.11.0 >
diff --git a/drivers/fpga/altera-ps-spi.c b/drivers/fpga/altera-ps-spi.c index 0db8def668ed..14f14efdf0d5 100644 --- a/drivers/fpga/altera-ps-spi.c +++ b/drivers/fpga/altera-ps-spi.c @@ -149,12 +149,23 @@ static int altera_ps_write_init(struct fpga_manager *mgr, static void rev_buf(char *buf, size_t len) { - const char *fw_end = (buf + len); + u32 *fw32 = (u32 *)buf; + size_t extra_bytes = (len & 0x03); + const u32 *fw_end = (u32 *)(buf + len - extra_bytes); /* set buffer to lsb first */ - while (buf < fw_end) { - *buf = bitrev8(*buf); - buf++; + while (fw32 < fw_end) { + *fw32 = bitrev8x4(*fw32); + fw32++; + } + + if (extra_bytes) { + buf = (char *)fw_end; + while (extra_bytes) { + *buf = bitrev8(*buf); + buf++; + extra_bytes--; + } } }
Speed up bit reversal by using hardware bit reversal Add extra code to handle less than 4byte remnants, if any Signed-off-by: Joshua Clayton <stillcompiling@gmail.com> --- drivers/fpga/altera-ps-spi.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-)