With CPU_DADDI_WORKAROUNDS enabled __delay assembles with a macro in a
branch delay slot:
{standard input}: Assembler messages:
{standard input}:18: Warning: Macro instruction expanded into multiple
instructions in a branch delay slot
and broken code results:
0000000000000000 <__delay>:
0: 1480ffff bnez a0,0 <__delay>
4: 24010001 li at,1
8: 0081202f dsubu a0,a0,at
c: 03e00008 jr ra
10: 00000000 nop
14: 00000000 nop
Consequently the function loops indefinitely, showing up prominently as a
hang in the delay loop calibration at bootstrap.
This change corrects the problem by forcing the immediate 1 into a
register while keeping code produced identical where CPU_DADDI_WORKAROUNDS
is disabled.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6669/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Having received another series of whitespace patches I decided to do this
once and for all rather than dealing with this kind of patches trickling
in forever.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
When building a 32-bit kernel for RBTX4927 with gcc version 4.1.2 20061115
(prerelease) (Ubuntu 4.1.1-21), I get:
arch/mips/lib/delay.c:24:5: warning: "__SIZEOF_LONG__" is not defined
As a consequence, __delay() always uses the 64-bit "dsubu" instruction.
Replace the check for "__SIZEOF_LONG__ == 4" by "BITS_PER_LONG == 32" to
fix this.
Introduced by commit 5210edcd52 [MIPS: Make
__{,n,u}delay declarations match definitions and generic delay.h"]
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Patchwork: https://patchwork.linux-mips.org/patch/4678/
Acked-by: David Daney <david.daney@cavium.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
At some recent point arch/mips/include/asm/delay.h has started being
included into csrc-octeon.c where the __?delay() functions are defined.
This causes a compile failure due to conflicting declarations and
definitions of the functions.
It turns out that the generic definitions in arch/mips/lib/delay.c also
conflict.
Proposed fix: Declare the functions to take unsigned long parameters
just like asm-generic (and x86) does. Update __delay to agree
(__ndelay and __udelay need no change).
Bonus: Get rid of 'inline' from __delay() definition, as it is globally
visible, and the compiler should be making this decision itself (it does
in fact inline the function without being told to).
Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/4354/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Outlining fixes the issue were on certain CPUs such as the R10000 family
the delay loop would need an extra cycle if it overlaps a cacheline
boundary.
The rewrite also fixes build errors with GCC 4.4 which was changed in
way incompatible with the kernel's inline assembly.
Relying on pure C for computation of the delay value removes the need for
explicit. The price we pay is a slight slowdown of the computation - to
be fixed on another day.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Maciej W. Rozycki