mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-30 09:06:44 +07:00
797a796a13
This provides unified readq()/writeq() helper functions for 32-bit
drivers.
For some cases, readq/writeq without atomicity is harmful, and order of
io access has to be specified explicitly. So in this patch, new two
header files which contain non-atomic readq/writeq are added.
- <asm-generic/io-64-nonatomic-lo-hi.h> provides non-atomic readq/
writeq with the order of lower address -> higher address
- <asm-generic/io-64-nonatomic-hi-lo.h> provides non-atomic readq/
writeq with reversed order
This allows us to remove some readq()s that were added drivers when the
default non-atomic ones were removed in commit dbee8a0aff ("x86:
remove 32-bit versions of readq()/writeq()")
The drivers which need readq/writeq but can do with the non-atomic ones
must add the line:
#include <asm-generic/io-64-nonatomic-lo-hi.h> /* or hi-lo.h */
But this will be nop in 64-bit environments, and no other #ifdefs are
required. So I believe that this patch can solve the problem of
1. driver-specific readq/writeq
2. atomicity and order of io access
This patch is tested with building allyesconfig and allmodconfig as
ARCH=x86 and ARCH=i386 on top of tip/master.
Cc: Kashyap Desai <Kashyap.Desai@lsi.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Ravi Anand <ravi.anand@qlogic.com>
Cc: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Jason Uhlenkott <juhlenko@akamai.com>
Cc: James Bottomley <James.Bottomley@parallels.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: James Bottomley <jbottomley@parallels.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Hitoshi Mitake <h.mitake@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
29 lines
536 B
C
29 lines
536 B
C
#ifndef _ASM_IO_64_NONATOMIC_LO_HI_H_
|
|
#define _ASM_IO_64_NONATOMIC_LO_HI_H_
|
|
|
|
#include <linux/io.h>
|
|
#include <asm-generic/int-ll64.h>
|
|
|
|
#ifndef readq
|
|
static inline __u64 readq(const volatile void __iomem *addr)
|
|
{
|
|
const volatile u32 __iomem *p = addr;
|
|
u32 low, high;
|
|
|
|
low = readl(p);
|
|
high = readl(p + 1);
|
|
|
|
return low + ((u64)high << 32);
|
|
}
|
|
#endif
|
|
|
|
#ifndef writeq
|
|
static inline void writeq(__u64 val, volatile void __iomem *addr)
|
|
{
|
|
writel(val, addr);
|
|
writel(val >> 32, addr + 4);
|
|
}
|
|
#endif
|
|
|
|
#endif /* _ASM_IO_64_NONATOMIC_LO_HI_H_ */
|