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authorVincent Guittot <vincent.guittot@linaro.org>2023-12-11 11:48:53 +0100
committerIngo Molnar <mingo@kernel.org>2023-12-23 15:52:35 +0100
commit50b813b147e9eb6546a1fc49d4e703e6d23691f2 (patch)
tree98d305e88c2c5486f5364e39dcdb5845b5aae7e5 /drivers/acpi
parent15cbbd1d317e07b4e5c6aca5d4c5579539a82784 (diff)
cpufreq/cppc: Move and rename cppc_cpufreq_{perf_to_khz|khz_to_perf}()
Move and rename cppc_cpufreq_perf_to_khz() and cppc_cpufreq_khz_to_perf() to use them outside cppc_cpufreq in topology_init_cpu_capacity_cppc(). Modify the interface to use struct cppc_perf_caps *caps instead of struct cppc_cpudata *cpu_data as we only use the fields of cppc_perf_caps. cppc_cpufreq was converting the lowest and nominal freq from MHz to kHz before using them. We move this conversion inside cppc_perf_to_khz and cppc_khz_to_perf to make them generic and usable outside cppc_cpufreq. No functional change Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Pierre Gondois <pierre.gondois@arm.com> Acked-by: Rafael J. Wysocki <rafael@kernel.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lore.kernel.org/r/20231211104855.558096-6-vincent.guittot@linaro.org
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/cppc_acpi.c104
1 files changed, 104 insertions, 0 deletions
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 7ff269a78c20..d155a86a8614 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -39,6 +39,9 @@
#include <linux/rwsem.h>
#include <linux/wait.h>
#include <linux/topology.h>
+#include <linux/dmi.h>
+#include <linux/units.h>
+#include <asm/unaligned.h>
#include <acpi/cppc_acpi.h>
@@ -1760,3 +1763,104 @@ unsigned int cppc_get_transition_latency(int cpu_num)
return latency_ns;
}
EXPORT_SYMBOL_GPL(cppc_get_transition_latency);
+
+/* Minimum struct length needed for the DMI processor entry we want */
+#define DMI_ENTRY_PROCESSOR_MIN_LENGTH 48
+
+/* Offset in the DMI processor structure for the max frequency */
+#define DMI_PROCESSOR_MAX_SPEED 0x14
+
+/* Callback function used to retrieve the max frequency from DMI */
+static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
+{
+ const u8 *dmi_data = (const u8 *)dm;
+ u16 *mhz = (u16 *)private;
+
+ if (dm->type == DMI_ENTRY_PROCESSOR &&
+ dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
+ u16 val = (u16)get_unaligned((const u16 *)
+ (dmi_data + DMI_PROCESSOR_MAX_SPEED));
+ *mhz = val > *mhz ? val : *mhz;
+ }
+}
+
+/* Look up the max frequency in DMI */
+static u64 cppc_get_dmi_max_khz(void)
+{
+ u16 mhz = 0;
+
+ dmi_walk(cppc_find_dmi_mhz, &mhz);
+
+ /*
+ * Real stupid fallback value, just in case there is no
+ * actual value set.
+ */
+ mhz = mhz ? mhz : 1;
+
+ return KHZ_PER_MHZ * mhz;
+}
+
+/*
+ * If CPPC lowest_freq and nominal_freq registers are exposed then we can
+ * use them to convert perf to freq and vice versa. The conversion is
+ * extrapolated as an affine function passing by the 2 points:
+ * - (Low perf, Low freq)
+ * - (Nominal perf, Nominal freq)
+ */
+unsigned int cppc_perf_to_khz(struct cppc_perf_caps *caps, unsigned int perf)
+{
+ s64 retval, offset = 0;
+ static u64 max_khz;
+ u64 mul, div;
+
+ if (caps->lowest_freq && caps->nominal_freq) {
+ mul = caps->nominal_freq - caps->lowest_freq;
+ mul *= KHZ_PER_MHZ;
+ div = caps->nominal_perf - caps->lowest_perf;
+ offset = caps->nominal_freq * KHZ_PER_MHZ -
+ div64_u64(caps->nominal_perf * mul, div);
+ } else {
+ if (!max_khz)
+ max_khz = cppc_get_dmi_max_khz();
+ mul = max_khz;
+ div = caps->highest_perf;
+ }
+
+ retval = offset + div64_u64(perf * mul, div);
+ if (retval >= 0)
+ return retval;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(cppc_perf_to_khz);
+
+unsigned int cppc_khz_to_perf(struct cppc_perf_caps *caps, unsigned int freq)
+{
+ s64 retval, offset = 0;
+ static u64 max_khz;
+ u64 mul, div;
+
+ if (caps->lowest_freq && caps->nominal_freq) {
+ mul = caps->nominal_perf - caps->lowest_perf;
+ div = caps->nominal_freq - caps->lowest_freq;
+ /*
+ * We don't need to convert to kHz for computing offset and can
+ * directly use nominal_freq and lowest_freq as the div64_u64
+ * will remove the frequency unit.
+ */
+ offset = caps->nominal_perf -
+ div64_u64(caps->nominal_freq * mul, div);
+ /* But we need it for computing the perf level. */
+ div *= KHZ_PER_MHZ;
+ } else {
+ if (!max_khz)
+ max_khz = cppc_get_dmi_max_khz();
+ mul = caps->highest_perf;
+ div = max_khz;
+ }
+
+ retval = offset + div64_u64(freq * mul, div);
+ if (retval >= 0)
+ return retval;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(cppc_khz_to_perf);