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/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2019 Intel Corporation
*/
#include <linux/cpufreq.h>
#include "i915_drv.h"
#include "intel_gt.h"
#include "intel_llc.h"
#include "intel_sideband.h"
struct ia_constants {
unsigned int min_gpu_freq;
unsigned int max_gpu_freq;
unsigned int min_ring_freq;
unsigned int max_ia_freq;
};
static struct intel_gt *llc_to_gt(struct intel_llc *llc)
{
return container_of(llc, struct intel_gt, llc);
}
static unsigned int cpu_max_MHz(void)
{
struct cpufreq_policy *policy;
unsigned int max_khz;
policy = cpufreq_cpu_get(0);
if (policy) {
max_khz = policy->cpuinfo.max_freq;
cpufreq_cpu_put(policy);
} else {
/*
* Default to measured freq if none found, PCU will ensure we
* don't go over
*/
max_khz = tsc_khz;
}
return max_khz / 1000;
}
static bool get_ia_constants(struct intel_llc *llc,
struct ia_constants *consts)
{
struct drm_i915_private *i915 = llc_to_gt(llc)->i915;
struct intel_rps *rps = &llc_to_gt(llc)->rps;
if (!HAS_LLC(i915) || IS_DGFX(i915))
return false;
if (rps->max_freq <= rps->min_freq)
return false;
consts->max_ia_freq = cpu_max_MHz();
consts->min_ring_freq =
intel_uncore_read(llc_to_gt(llc)->uncore, DCLK) & 0xf;
/* convert DDR frequency from units of 266.6MHz to bandwidth */
consts->min_ring_freq = mult_frac(consts->min_ring_freq, 8, 3);
consts->min_gpu_freq = rps->min_freq;
consts->max_gpu_freq = rps->max_freq;
if (INTEL_GEN(i915) >= 9) {
/* Convert GT frequency to 50 HZ units */
consts->min_gpu_freq /= GEN9_FREQ_SCALER;
consts->max_gpu_freq /= GEN9_FREQ_SCALER;
}
return true;
}
static void calc_ia_freq(struct intel_llc *llc,
unsigned int gpu_freq,
const struct ia_constants *consts,
unsigned int *out_ia_freq,
unsigned int *out_ring_freq)
{
struct drm_i915_private *i915 = llc_to_gt(llc)->i915;
const int diff = consts->max_gpu_freq - gpu_freq;
unsigned int ia_freq = 0, ring_freq = 0;
if (INTEL_GEN(i915) >= 9) {
/*
* ring_freq = 2 * GT. ring_freq is in 100MHz units
* No floor required for ring frequency on SKL.
*/
ring_freq = gpu_freq;
} else if (INTEL_GEN(i915) >= 8) {
/* max(2 * GT, DDR). NB: GT is 50MHz units */
ring_freq = max(consts->min_ring_freq, gpu_freq);
} else if (IS_HASWELL(i915)) {
ring_freq = mult_frac(gpu_freq, 5, 4);
ring_freq = max(consts->min_ring_freq, ring_freq);
/* leave ia_freq as the default, chosen by cpufreq */
} else {
const int min_freq = 15;
const int scale = 180;
/*
* On older processors, there is no separate ring
* clock domain, so in order to boost the bandwidth
* of the ring, we need to upclock the CPU (ia_freq).
*
* For GPU frequencies less than 750MHz,
* just use the lowest ring freq.
*/
if (gpu_freq < min_freq)
ia_freq = 800;
else
ia_freq = consts->max_ia_freq - diff * scale / 2;
ia_freq = DIV_ROUND_CLOSEST(ia_freq, 100);
}
*out_ia_freq = ia_freq;
*out_ring_freq = ring_freq;
}
static void gen6_update_ring_freq(struct intel_llc *llc)
{
struct drm_i915_private *i915 = llc_to_gt(llc)->i915;
struct ia_constants consts;
unsigned int gpu_freq;
if (!get_ia_constants(llc, &consts))
return;
/*
* For each potential GPU frequency, load a ring frequency we'd like
* to use for memory access. We do this by specifying the IA frequency
* the PCU should use as a reference to determine the ring frequency.
*/
for (gpu_freq = consts.max_gpu_freq;
gpu_freq >= consts.min_gpu_freq;
gpu_freq--) {
unsigned int ia_freq, ring_freq;
calc_ia_freq(llc, gpu_freq, &consts, &ia_freq, &ring_freq);
sandybridge_pcode_write(i915,
GEN6_PCODE_WRITE_MIN_FREQ_TABLE,
ia_freq << GEN6_PCODE_FREQ_IA_RATIO_SHIFT |
ring_freq << GEN6_PCODE_FREQ_RING_RATIO_SHIFT |
gpu_freq);
}
}
void intel_llc_enable(struct intel_llc *llc)
{
gen6_update_ring_freq(llc);
}
void intel_llc_disable(struct intel_llc *llc)
{
/* Currently there is no HW configuration to be done to disable. */
}
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftest_llc.c"
#endif
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