Re: [PATCH 2/5] include: add setbits32/clrbits32/clrsetbits32/setbits64/clrbits64/clrsetbits64 in linux/setbits.h
From: Scott Wood <oss@buserror.net>
Date: 2018-09-07 20:21:03
Also in:
cocci, linux-amlogic, linux-arm-kernel, linux-ide, lkml, netdev
On Fri, 2018-09-07 at 19:41 +0000, Corentin Labbe wrote:
quoted hunk ↗ jump to hunk
This patch adds setbits32/clrbits32/clrsetbits32 and setbits64/clrbits64/clrsetbits64 in linux/setbits.h header. Signed-off-by: Corentin Labbe <clabbe@baylibre.com> --- include/linux/setbits.h | 55 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 include/linux/setbits.hdiff --git a/include/linux/setbits.h b/include/linux/setbits.h new file mode 100644 index 000000000000..3e1e273551bb --- /dev/null +++ b/include/linux/setbits.h@@ -0,0 +1,55 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __LINUX_SETBITS_H +#define __LINUX_SETBITS_H + +#include <linux/io.h> + +#define __setbits(readfunction, writefunction, addr, set) \ + writefunction((readfunction(addr) | (set)), addr) +#define __clrbits(readfunction, writefunction, addr, mask) \ + writefunction((readfunction(addr) & ~(mask)), addr) +#define __clrsetbits(readfunction, writefunction, addr, mask, set) \ + writefunction(((readfunction(addr) & ~(mask)) | (set)), addr) +#define __setclrbits(readfunction, writefunction, addr, mask, set) \ + writefunction(((readfunction(addr) | (seti)) & ~(mask)), addr) + +#define setbits32(addr, set) __setbits(readl, writel, addr, set) +#define setbits32_relaxed(addr, set) __setbits(readl_relaxed,writel_relaxed, \ + addr, set) + +#define clrbits32(addr, mask) __clrbits(readl, writel, addr, mask) +#define clrbits32_relaxed(addr, mask) __clrbits(readl_relaxed, writel_relaxed, \ + addr, mask)
So now setbits32/clrbits32 is implicitly little-endian? Introducing new implicit-endian accessors is probably a bad thing in general, but doing it with a name that until this patchset was implicitly big-endian (at least on powerpc) seems worse. Why not setbits32_le()?
+ +#define clrsetbits32(addr, mask, set) __clrsetbits(readl, writel, addr, mask, set) +#define clrsetbits32_relaxed(addr, mask, set) __clrsetbits(readl_relaxed, \ + writel_relaxed, \ + addr, mask, set) + +#define setclrbits32(addr, mask, set) __setclrbits(readl, writel, addr, mask, set) +#define setclrbits32_relaxed(addr, mask, set) __setclrbits(readl_relaxed, \ + writel_relaxed, \ + addr, mask, set)
What's the use case for setclrbits? I don't see it used anywhere in this patchset (not even in the coccinelle patterns), it doesn't seem like it would be a common pattern, and it could easily get confused with clrsetbits. -Scott