On Fri, Sep 07, 2018 at 03:00:40PM -0500, Scott Wood wrote:

On Fri, 2018-09-07 at 19:41 +0000, Corentin Labbe wrote:

quoted

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.h

diff --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()?

I believed that writel/readl was endian agnostic, but It seems that I was wrong.
So I will use _le32.

quoted

+
+#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.

It is absent from the coccinelle script due to copy/paste error.
And absent from patchset since it is only two possible example that I can test.

If you run the next fixed coccinelle script, you will find some setclrbits.
Since I fear that mask and set could have some common bits sometimes, I prefer to keep separate clrsetbits and setclrbits.

Regards