intel_pstate: Optimize calculation for max/min_perf_adj

mul_fp(int_tofp(A), B) expands to:
((A << FRAC_BITS) * B) >> FRAC_BITS, so the same result can be obtained
via simple multiplication A * B.  Apply this observation to
max_perf * limits->max_perf and max_perf * limits->min_perf in
intel_pstate_get_min_max()."

Signed-off-by: Philippe Longepe <philippe.longepe@linux.intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 864214de5cdf55f1824444c32839bb0dfabb861f..5b5bfc1c90f15a73256f2bb851440303a440c0b5 100644 (file)
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -831,11 +831,11 @@ static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
         * policy, or by cpu specific default values determined through
         * experimentation.
         */
-       max_perf_adj = fp_toint(mul_fp(int_tofp(max_perf), limits->max_perf));
+       max_perf_adj = fp_toint(max_perf * limits->max_perf);
        *max = clamp_t(int, max_perf_adj,
                        cpu->pstate.min_pstate, cpu->pstate.turbo_pstate);
 
-       min_perf = fp_toint(mul_fp(int_tofp(max_perf), limits->min_perf));
+       min_perf = fp_toint(max_perf * limits->min_perf);
        *min = clamp_t(int, min_perf, cpu->pstate.min_pstate, max_perf);
 }