Re: [PATCH v12 6/6] fpga-manager: altera-ps-spi: use bitrev8x4
From: Alan Tull <hidden>
Date: 2017-06-05 15:13:50
Also in:
linux-arm-kernel, lkml
On Fri, Jun 2, 2017 at 3:30 PM, Joshua Clayton [off-list ref] 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 <redacted>
Signed-off-by: Alan Tull <redacted>
quoted hunk ↗ jump to hunk
--- 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
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