diff options
| author | Paul Burton <paul.burton@imgtec.com> | 2016-08-19 18:18:26 +0100 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2016-09-29 18:59:49 +0200 |
| commit | 72c70f010dfcc9ea6cc13500602a29e33748452f (patch) | |
| tree | c891259ef4181e3ebac3fc2bf7b9a85034cdc9ce /arch/mips | |
| parent | 3021773c7c3e75e20b693931a19362681e744ea9 (diff) | |
MIPS: Stop setting I6400 FTLBP
The FTLBP field in Config7 for the I6400 is intended as chicken bits for
debugging rather than as a field that software actually makes use of.
For best performance, FTLBP should be left at its default value of 0
with all TLB writes hitting the FTLB by default.
Additionally, since set_ftlb_enable is called from decode_configs before
decode_config4 which determines the size of the TLBs, this was
previously always setting FTLBP=3 for a 3:1 FTLB:VTLB write ratio which
makes abysmal use of the available FTLB resources.
This effectively reverts b0c4e1b79d8a ("MIPS: Set up FTLB probability
for I6400").
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: b0c4e1b79d8a ("MIPS: Set up FTLB probability for I6400")
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14021/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips')
| -rw-r--r-- | arch/mips/include/asm/mipsregs.h | 2 | ||||
| -rw-r--r-- | arch/mips/kernel/cpu-probe.c | 9 |
2 files changed, 2 insertions, 9 deletions
diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h index def9d8d13f6e..7dd2dd47909a 100644 --- a/arch/mips/include/asm/mipsregs.h +++ b/arch/mips/include/asm/mipsregs.h @@ -660,8 +660,6 @@ #define MIPS_CONF7_IAR (_ULCAST_(1) << 10) #define MIPS_CONF7_AR (_ULCAST_(1) << 16) -/* FTLB probability bits for R6 */ -#define MIPS_CONF7_FTLBP_SHIFT (18) /* WatchLo* register definitions */ #define MIPS_WATCHLO_IRW (_ULCAST_(0x7) << 0) diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c index a88d44247cc8..ae290506873b 100644 --- a/arch/mips/kernel/cpu-probe.c +++ b/arch/mips/kernel/cpu-probe.c @@ -555,13 +555,8 @@ static int set_ftlb_enable(struct cpuinfo_mips *c, int enable) write_c0_config6(config & ~MIPS_CONF6_FTLBEN); break; case CPU_I6400: - /* I6400 & related cores use Config7 to configure FTLB */ - config = read_c0_config7(); - /* Clear the old probability value */ - config &= ~(3 << MIPS_CONF7_FTLBP_SHIFT); - write_c0_config7(config | (calculate_ftlb_probability(c) - << MIPS_CONF7_FTLBP_SHIFT)); - break; + /* There's no way to disable the FTLB */ + return !enable; case CPU_LOONGSON3: /* Flush ITLB, DTLB, VTLB and FTLB */ write_c0_diag(LOONGSON_DIAG_ITLB | LOONGSON_DIAG_DTLB | |