On Sun, Jun 27, 2010 at 08:44:03AM -0500, Shinya Kuribayashi wrote:
> fls()/__fls() defined at <asm/bitops.h>, doesn't use CLZ unless it's
> explicitly requested via <cpu-features-overrides.h>. In other words,
> as long as depending on cpu_data[0].isa_level, CLZ is nerver used for
> fls()/__fls().
...
> It's MIPS32 machine and luckily clz() is left there, then let's go back
> to the original shape.
>
> Signed-off-by: Shinya Kuribayashi <skuribay@xxxxxxxxx>
Thanks! You are correct in your analysis and make a good point that
clz should be used in interrupt handling. I think, though, that it's
better to go ahead and supply a full-blown cpu-features-override.h
rather than focusing on this one case. This way fls() will be optimized
to use clz everywhere and any other optimizations that depend on constant
cpu_has_* values will also be used.
The following patch provides cpu-features-override.h and removes the
unused clz() function in asic_int.c.
Signed-off-by: David VomLehn <dvomlehn@xxxxxxxxx>
---
.../asm/mach-powertv/cpu-feature-overrides.h | 59 ++++++++++++++++++++
arch/mips/powertv/asic/asic_int.c | 13 ----
2 files changed, 59 insertions(+), 13 deletions(-)
diff --git a/arch/mips/include/asm/mach-powertv/cpu-feature-overrides.h b/arch/mips/include/asm/mach-powertv/cpu-feature-overrides.h
new file mode 100644
index 0000000..f751e3e
--- /dev/null
+++ b/arch/mips/include/asm/mach-powertv/cpu-feature-overrides.h
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2010 Cisco Systems, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef _ASM_MACH_POWERTV_CPU_FEATURE_OVERRIDES_H_
+#define _ASM_MACH_POWERTV_CPU_FEATURE_OVERRIDES_H_
+#define cpu_has_tlb 1
+#define cpu_has_4kex 1
+#define cpu_has_3k_cache 0
+#define cpu_has_4k_cache 1
+#define cpu_has_tx39_cache 0
+#define cpu_has_fpu 0
+#define cpu_has_counter 1
+#define cpu_has_watch 1
+#define cpu_has_divec 1
+#define cpu_has_vce 0
+#define cpu_has_cache_cdex_p 0
+#define cpu_has_cache_cdex_s 0
+#define cpu_has_mcheck 1
+#define cpu_has_ejtag 1
+#define cpu_has_llsc 1
+#define cpu_has_mips16 0
+#define cpu_has_mdmx 0
+#define cpu_has_mips3d 0
+#define cpu_has_smartmips 0
+#define cpu_has_vtag_icache 0
+#define cpu_has_dc_aliases 0
+#define cpu_has_ic_fills_f_dc 0
+#define cpu_has_mips32r1 0
+#define cpu_has_mips32r2 1
+#define cpu_has_mips64r1 0
+#define cpu_has_mips64r2 0
+#define cpu_has_dsp 0
+#define cpu_has_mipsmt 0
+#define cpu_has_userlocal 0
+#define cpu_has_nofpuex 0
+#define cpu_has_64bits 0
+#define cpu_has_64bit_zero_reg 0
+#define cpu_has_vint 1
+#define cpu_has_veic 1
+#define cpu_has_inclusive_pcaches 0
+
+#define cpu_dcache_line_size() 32
+#define cpu_icache_line_size() 32
+#endif
diff --git a/arch/mips/powertv/asic/asic_int.c b/arch/mips/powertv/asic/asic_int.c
index 529c44a..7362f63 100644
--- a/arch/mips/powertv/asic/asic_int.c
+++ b/arch/mips/powertv/asic/asic_int.c
@@ -68,19 +68,6 @@ static void asic_irqdispatch(void)
do_IRQ(irq);
}
-static inline int clz(unsigned long x)
-{
- __asm__(
- " .set push \n"
- " .set mips32 \n"
- " clz %0, %1 \n"
- " .set pop \n"
- : "=r" (x)
- : "r" (x));
-
- return x;
-}
-
/*
* Version of ffs that only looks at bits 12..15.
*/
