Merge tag 'mips-fixes_5.18_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux

Pull MIPS fix from Thomas Bogendoerfer:
 "Extend R4000/R4400 CPU erratum workaround to all revisions"

* tag 'mips-fixes_5.18_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  MIPS: Fix CP0 counter erratum detection for R4k CPUs
This commit is contained in:
Linus Torvalds
2022-05-05 10:27:30 -07:00
2 changed files with 7 additions and 12 deletions
+4 -4
View File
@@ -40,9 +40,9 @@
typedef unsigned int cycles_t;
/*
* On R4000/R4400 before version 5.0 an erratum exists such that if the
* cycle counter is read in the exact moment that it is matching the
* compare register, no interrupt will be generated.
* On R4000/R4400 an erratum exists such that if the cycle counter is
* read in the exact moment that it is matching the compare register,
* no interrupt will be generated.
*
* There is a suggested workaround and also the erratum can't strike if
* the compare interrupt isn't being used as the clock source device.
@@ -63,7 +63,7 @@ static inline int can_use_mips_counter(unsigned int prid)
if (!__builtin_constant_p(cpu_has_counter))
asm volatile("" : "=m" (cpu_data[0].options));
if (likely(cpu_has_counter &&
prid >= (PRID_IMP_R4000 | PRID_REV_ENCODE_44(5, 0))))
prid > (PRID_IMP_R4000 | PRID_REV_ENCODE_44(15, 15))))
return 1;
else
return 0;
+3 -8
View File
@@ -141,15 +141,10 @@ static __init int cpu_has_mfc0_count_bug(void)
case CPU_R4400MC:
/*
* The published errata for the R4400 up to 3.0 say the CPU
* has the mfc0 from count bug.
* has the mfc0 from count bug. This seems the last version
* produced.
*/
if ((current_cpu_data.processor_id & 0xff) <= 0x30)
return 1;
/*
* we assume newer revisions are ok
*/
return 0;
return 1;
}
return 0;