Power throttling make deterministic delay loops impossible.
Re-implement delays using the cycle counter. This also allows us to
get rid of the code that calculates loops per jiffy.
Signed-off-by: David Daney <ddaney@xxxxxxxxxxxxxxxxxx>
---
arch/mips/cavium-octeon/csrc-octeon.c | 55 ++++++++++++++++++++
arch/mips/cavium-octeon/setup.c | 4 +-
.../asm/mach-cavium-octeon/cpu-feature-overrides.h | 11 ----
arch/mips/include/asm/octeon/octeon.h | 1 +
4 files changed, 58 insertions(+), 13 deletions(-)
diff --git a/arch/mips/cavium-octeon/csrc-octeon.c b/arch/mips/cavium-octeon/csrc-octeon.c
index 0bf4bbe..a7d2b39 100644
--- a/arch/mips/cavium-octeon/csrc-octeon.c
+++ b/arch/mips/cavium-octeon/csrc-octeon.c
@@ -88,3 +88,58 @@ void __init plat_time_init(void)
clocksource_set_clock(&clocksource_mips, mips_hpt_frequency);
clocksource_register(&clocksource_mips);
}
+
+static u64 octeon_udelay_factor;
+static u64 octeon_ndelay_factor;
+
+void __init octeon_setup_delays(void)
+{
+ octeon_udelay_factor = octeon_get_clock_rate() / 1000000;
+ /*
+ * For __ndelay we divide by 2^16, so the factor is multiplied
+ * by the same amount.
+ */
+ octeon_ndelay_factor = (octeon_udelay_factor * 0x10000ull) / 1000ull;
+
+ preset_lpj = octeon_get_clock_rate() / HZ;
+}
+
+void __udelay(unsigned long us)
+{
+ u64 cur, end, inc;
+
+ cur = read_c0_cvmcount();
+
+ inc = us * octeon_udelay_factor;
+ end = cur + inc;
+
+ while (end > cur)
+ cur = read_c0_cvmcount();
+}
+EXPORT_SYMBOL(__udelay);
+
+void __ndelay(unsigned long ns)
+{
+ u64 cur, end, inc;
+
+ cur = read_c0_cvmcount();
+
+ inc = ((ns * octeon_ndelay_factor) >> 16);
+ end = cur + inc;
+
+ while (end > cur)
+ cur = read_c0_cvmcount();
+}
+EXPORT_SYMBOL(__ndelay);
+
+void __delay(unsigned long loops)
+{
+ u64 cur, end;
+
+ cur = read_c0_cvmcount();
+ end = cur + loops;
+
+ while (end > cur)
+ cur = read_c0_cvmcount();
+}
+EXPORT_SYMBOL(__delay);
diff --git a/arch/mips/cavium-octeon/setup.c b/arch/mips/cavium-octeon/setup.c
index d1b5ffa..6f36bc1 100644
--- a/arch/mips/cavium-octeon/setup.c
+++ b/arch/mips/cavium-octeon/setup.c
@@ -598,13 +598,13 @@ void __init prom_init(void)
* the filesystem. Also specify the calibration delay
* to avoid calculating it every time.
*/
- strcat(arcs_cmdline, " rw root=1f00"
- " lpj=60176 slram=root,0x40000000,+1073741824");
+ strcat(arcs_cmdline, " rw root=1f00 slram=root,0x40000000,+1073741824");
}
mips_hpt_frequency = octeon_get_clock_rate();
octeon_init_cvmcount();
+ octeon_setup_delays();
_machine_restart = octeon_restart;
_machine_halt = octeon_halt;
diff --git a/arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h b/arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h
index bbf0540..e412777 100644
--- a/arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h
+++ b/arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h
@@ -61,22 +61,11 @@
#define kernel_uses_smartmips_rixi (cpu_data[0].cputype == CPU_CAVIUM_OCTEON_PLUS)
-#define ARCH_HAS_READ_CURRENT_TIMER 1
#define ARCH_HAS_IRQ_PER_CPU 1
#define ARCH_HAS_SPINLOCK_PREFETCH 1
#define spin_lock_prefetch(x) prefetch(x)
#define PREFETCH_STRIDE 128
-static inline int read_current_timer(unsigned long *result)
-{
- asm volatile ("rdhwr %0,$31\n"
-#ifndef CONFIG_64BIT
- "\tsll %0, 0"
-#endif
- : "=r" (*result));
- return 0;
-}
-
static inline int octeon_has_saa(void)
{
int id;
diff --git a/arch/mips/include/asm/octeon/octeon.h b/arch/mips/include/asm/octeon/octeon.h
index ca6214b..8a3eb3b 100644
--- a/arch/mips/include/asm/octeon/octeon.h
+++ b/arch/mips/include/asm/octeon/octeon.h
@@ -50,6 +50,7 @@ extern void octeon_crypto_disable(struct octeon_cop2_state *state,
extern asmlinkage void octeon_cop2_restore(struct octeon_cop2_state *task);
extern void octeon_init_cvmcount(void);
+extern void octeon_setup_delays(void);
#define OCTEON_ARGV_MAX_ARGS 64
#define OCTOEN_SERIAL_LEN 20
--
1.6.6.1
