From mboxrd@z Thu Jan 1 00:00:00 1970 From: stillcompiling@gmail.com (Joshua Clayton) Date: Thu, 25 May 2017 10:29:11 -0700 Subject: [PATCH v11 6/6] fpga-manager: altera-ps-spi: use bitrev8x4 In-Reply-To: <20170525172911.11467-1-stillcompiling@gmail.com> References: <20170525172911.11467-1-stillcompiling@gmail.com> Message-ID: <20170525172911.11467-7-stillcompiling@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 --- 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 9e90f8086cd5..baddead15476 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