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f45f89a778
The function tegra194_get_speed_common() uses hardware timers to calculate the current CPUFREQ and so rename this function to be tegra194_calculate_speed() to reflect what it does. Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
433 lines
11 KiB
C
433 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved
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*/
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#include <linux/cpu.h>
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#include <linux/cpufreq.h>
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#include <linux/delay.h>
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#include <linux/dma-mapping.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <asm/smp_plat.h>
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#include <soc/tegra/bpmp.h>
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#include <soc/tegra/bpmp-abi.h>
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#define KHZ 1000
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#define REF_CLK_MHZ 408 /* 408 MHz */
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#define US_DELAY 500
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#define CPUFREQ_TBL_STEP_HZ (50 * KHZ * KHZ)
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#define MAX_CNT ~0U
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/* cpufreq transisition latency */
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#define TEGRA_CPUFREQ_TRANSITION_LATENCY (300 * 1000) /* unit in nanoseconds */
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enum cluster {
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CLUSTER0,
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CLUSTER1,
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CLUSTER2,
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CLUSTER3,
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MAX_CLUSTERS,
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};
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struct tegra194_cpufreq_data {
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void __iomem *regs;
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size_t num_clusters;
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struct cpufreq_frequency_table **tables;
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};
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struct tegra_cpu_ctr {
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u32 cpu;
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u32 coreclk_cnt, last_coreclk_cnt;
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u32 refclk_cnt, last_refclk_cnt;
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};
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struct read_counters_work {
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struct work_struct work;
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struct tegra_cpu_ctr c;
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};
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static struct workqueue_struct *read_counters_wq;
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static void get_cpu_cluster(void *cluster)
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{
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u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;
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*((uint32_t *)cluster) = MPIDR_AFFINITY_LEVEL(mpidr, 1);
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}
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/*
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* Read per-core Read-only system register NVFREQ_FEEDBACK_EL1.
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* The register provides frequency feedback information to
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* determine the average actual frequency a core has run at over
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* a period of time.
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* [31:0] PLLP counter: Counts at fixed frequency (408 MHz)
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* [63:32] Core clock counter: counts on every core clock cycle
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* where the core is architecturally clocking
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*/
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static u64 read_freq_feedback(void)
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{
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u64 val = 0;
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asm volatile("mrs %0, s3_0_c15_c0_5" : "=r" (val) : );
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return val;
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}
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static inline u32 map_ndiv_to_freq(struct mrq_cpu_ndiv_limits_response
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*nltbl, u16 ndiv)
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{
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return nltbl->ref_clk_hz / KHZ * ndiv / (nltbl->pdiv * nltbl->mdiv);
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}
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static void tegra_read_counters(struct work_struct *work)
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{
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struct read_counters_work *read_counters_work;
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struct tegra_cpu_ctr *c;
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u64 val;
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/*
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* ref_clk_counter(32 bit counter) runs on constant clk,
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* pll_p(408MHz).
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* It will take = 2 ^ 32 / 408 MHz to overflow ref clk counter
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* = 10526880 usec = 10.527 sec to overflow
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*
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* Like wise core_clk_counter(32 bit counter) runs on core clock.
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* It's synchronized to crab_clk (cpu_crab_clk) which runs at
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* freq of cluster. Assuming max cluster clock ~2000MHz,
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* It will take = 2 ^ 32 / 2000 MHz to overflow core clk counter
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* = ~2.147 sec to overflow
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*/
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read_counters_work = container_of(work, struct read_counters_work,
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work);
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c = &read_counters_work->c;
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val = read_freq_feedback();
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c->last_refclk_cnt = lower_32_bits(val);
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c->last_coreclk_cnt = upper_32_bits(val);
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udelay(US_DELAY);
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val = read_freq_feedback();
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c->refclk_cnt = lower_32_bits(val);
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c->coreclk_cnt = upper_32_bits(val);
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}
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/*
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* Return instantaneous cpu speed
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* Instantaneous freq is calculated as -
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* -Takes sample on every query of getting the freq.
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* - Read core and ref clock counters;
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* - Delay for X us
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* - Read above cycle counters again
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* - Calculates freq by subtracting current and previous counters
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* divided by the delay time or eqv. of ref_clk_counter in delta time
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* - Return Kcycles/second, freq in KHz
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*
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* delta time period = x sec
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* = delta ref_clk_counter / (408 * 10^6) sec
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* freq in Hz = cycles/sec
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* = (delta cycles / x sec
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* = (delta cycles * 408 * 10^6) / delta ref_clk_counter
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* in KHz = (delta cycles * 408 * 10^3) / delta ref_clk_counter
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*
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* @cpu - logical cpu whose freq to be updated
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* Returns freq in KHz on success, 0 if cpu is offline
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*/
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static unsigned int tegra194_calculate_speed(u32 cpu)
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{
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struct read_counters_work read_counters_work;
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struct tegra_cpu_ctr c;
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u32 delta_refcnt;
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u32 delta_ccnt;
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u32 rate_mhz;
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/*
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* udelay() is required to reconstruct cpu frequency over an
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* observation window. Using workqueue to call udelay() with
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* interrupts enabled.
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*/
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read_counters_work.c.cpu = cpu;
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INIT_WORK_ONSTACK(&read_counters_work.work, tegra_read_counters);
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queue_work_on(cpu, read_counters_wq, &read_counters_work.work);
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flush_work(&read_counters_work.work);
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c = read_counters_work.c;
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if (c.coreclk_cnt < c.last_coreclk_cnt)
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delta_ccnt = c.coreclk_cnt + (MAX_CNT - c.last_coreclk_cnt);
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else
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delta_ccnt = c.coreclk_cnt - c.last_coreclk_cnt;
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if (!delta_ccnt)
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return 0;
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/* ref clock is 32 bits */
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if (c.refclk_cnt < c.last_refclk_cnt)
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delta_refcnt = c.refclk_cnt + (MAX_CNT - c.last_refclk_cnt);
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else
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delta_refcnt = c.refclk_cnt - c.last_refclk_cnt;
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if (!delta_refcnt) {
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pr_debug("cpufreq: %d is idle, delta_refcnt: 0\n", cpu);
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return 0;
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}
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rate_mhz = ((unsigned long)(delta_ccnt * REF_CLK_MHZ)) / delta_refcnt;
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return (rate_mhz * KHZ); /* in KHz */
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}
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static void get_cpu_ndiv(void *ndiv)
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{
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u64 ndiv_val;
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asm volatile("mrs %0, s3_0_c15_c0_4" : "=r" (ndiv_val) : );
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*(u64 *)ndiv = ndiv_val;
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}
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static void set_cpu_ndiv(void *data)
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{
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struct cpufreq_frequency_table *tbl = data;
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u64 ndiv_val = (u64)tbl->driver_data;
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asm volatile("msr s3_0_c15_c0_4, %0" : : "r" (ndiv_val));
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}
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static unsigned int tegra194_get_speed(u32 cpu)
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{
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struct tegra194_cpufreq_data *data = cpufreq_get_driver_data();
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struct cpufreq_frequency_table *pos;
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unsigned int rate;
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u64 ndiv;
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int ret;
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u32 cl;
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smp_call_function_single(cpu, get_cpu_cluster, &cl, true);
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/* reconstruct actual cpu freq using counters */
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rate = tegra194_calculate_speed(cpu);
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/* get last written ndiv value */
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ret = smp_call_function_single(cpu, get_cpu_ndiv, &ndiv, true);
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if (WARN_ON_ONCE(ret))
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return rate;
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/*
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* If the reconstructed frequency has acceptable delta from
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* the last written value, then return freq corresponding
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* to the last written ndiv value from freq_table. This is
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* done to return consistent value.
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*/
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cpufreq_for_each_valid_entry(pos, data->tables[cl]) {
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if (pos->driver_data != ndiv)
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continue;
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if (abs(pos->frequency - rate) > 115200) {
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pr_warn("cpufreq: cpu%d,cur:%u,set:%u,set ndiv:%llu\n",
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cpu, rate, pos->frequency, ndiv);
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} else {
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rate = pos->frequency;
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}
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break;
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}
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return rate;
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}
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static int tegra194_cpufreq_init(struct cpufreq_policy *policy)
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{
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struct tegra194_cpufreq_data *data = cpufreq_get_driver_data();
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u32 cpu;
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u32 cl;
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smp_call_function_single(policy->cpu, get_cpu_cluster, &cl, true);
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if (cl >= data->num_clusters)
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return -EINVAL;
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/* set same policy for all cpus in a cluster */
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for (cpu = (cl * 2); cpu < ((cl + 1) * 2); cpu++)
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cpumask_set_cpu(cpu, policy->cpus);
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policy->freq_table = data->tables[cl];
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policy->cpuinfo.transition_latency = TEGRA_CPUFREQ_TRANSITION_LATENCY;
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return 0;
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}
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static int tegra194_cpufreq_set_target(struct cpufreq_policy *policy,
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unsigned int index)
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{
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struct cpufreq_frequency_table *tbl = policy->freq_table + index;
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/*
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* Each core writes frequency in per core register. Then both cores
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* in a cluster run at same frequency which is the maximum frequency
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* request out of the values requested by both cores in that cluster.
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*/
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on_each_cpu_mask(policy->cpus, set_cpu_ndiv, tbl, true);
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return 0;
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}
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static struct cpufreq_driver tegra194_cpufreq_driver = {
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.name = "tegra194",
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.flags = CPUFREQ_STICKY | CPUFREQ_CONST_LOOPS |
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CPUFREQ_NEED_INITIAL_FREQ_CHECK,
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.verify = cpufreq_generic_frequency_table_verify,
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.target_index = tegra194_cpufreq_set_target,
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.get = tegra194_get_speed,
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.init = tegra194_cpufreq_init,
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.attr = cpufreq_generic_attr,
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};
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static void tegra194_cpufreq_free_resources(void)
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{
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destroy_workqueue(read_counters_wq);
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}
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static struct cpufreq_frequency_table *
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init_freq_table(struct platform_device *pdev, struct tegra_bpmp *bpmp,
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unsigned int cluster_id)
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{
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struct cpufreq_frequency_table *freq_table;
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struct mrq_cpu_ndiv_limits_response resp;
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unsigned int num_freqs, ndiv, delta_ndiv;
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struct mrq_cpu_ndiv_limits_request req;
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struct tegra_bpmp_message msg;
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u16 freq_table_step_size;
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int err, index;
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memset(&req, 0, sizeof(req));
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req.cluster_id = cluster_id;
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memset(&msg, 0, sizeof(msg));
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msg.mrq = MRQ_CPU_NDIV_LIMITS;
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msg.tx.data = &req;
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msg.tx.size = sizeof(req);
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msg.rx.data = &resp;
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msg.rx.size = sizeof(resp);
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err = tegra_bpmp_transfer(bpmp, &msg);
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if (err)
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return ERR_PTR(err);
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/*
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* Make sure frequency table step is a multiple of mdiv to match
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* vhint table granularity.
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*/
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freq_table_step_size = resp.mdiv *
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DIV_ROUND_UP(CPUFREQ_TBL_STEP_HZ, resp.ref_clk_hz);
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dev_dbg(&pdev->dev, "cluster %d: frequency table step size: %d\n",
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cluster_id, freq_table_step_size);
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delta_ndiv = resp.ndiv_max - resp.ndiv_min;
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if (unlikely(delta_ndiv == 0)) {
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num_freqs = 1;
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} else {
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/* We store both ndiv_min and ndiv_max hence the +1 */
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num_freqs = delta_ndiv / freq_table_step_size + 1;
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}
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num_freqs += (delta_ndiv % freq_table_step_size) ? 1 : 0;
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freq_table = devm_kcalloc(&pdev->dev, num_freqs + 1,
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sizeof(*freq_table), GFP_KERNEL);
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if (!freq_table)
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return ERR_PTR(-ENOMEM);
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for (index = 0, ndiv = resp.ndiv_min;
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ndiv < resp.ndiv_max;
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index++, ndiv += freq_table_step_size) {
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freq_table[index].driver_data = ndiv;
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freq_table[index].frequency = map_ndiv_to_freq(&resp, ndiv);
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}
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freq_table[index].driver_data = resp.ndiv_max;
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freq_table[index++].frequency = map_ndiv_to_freq(&resp, resp.ndiv_max);
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freq_table[index].frequency = CPUFREQ_TABLE_END;
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return freq_table;
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}
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static int tegra194_cpufreq_probe(struct platform_device *pdev)
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{
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struct tegra194_cpufreq_data *data;
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struct tegra_bpmp *bpmp;
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int err, i;
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data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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data->num_clusters = MAX_CLUSTERS;
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data->tables = devm_kcalloc(&pdev->dev, data->num_clusters,
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sizeof(*data->tables), GFP_KERNEL);
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if (!data->tables)
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return -ENOMEM;
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platform_set_drvdata(pdev, data);
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bpmp = tegra_bpmp_get(&pdev->dev);
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if (IS_ERR(bpmp))
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return PTR_ERR(bpmp);
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read_counters_wq = alloc_workqueue("read_counters_wq", __WQ_LEGACY, 1);
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if (!read_counters_wq) {
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dev_err(&pdev->dev, "fail to create_workqueue\n");
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err = -EINVAL;
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goto put_bpmp;
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}
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for (i = 0; i < data->num_clusters; i++) {
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data->tables[i] = init_freq_table(pdev, bpmp, i);
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if (IS_ERR(data->tables[i])) {
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err = PTR_ERR(data->tables[i]);
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goto err_free_res;
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}
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}
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tegra194_cpufreq_driver.driver_data = data;
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err = cpufreq_register_driver(&tegra194_cpufreq_driver);
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if (!err)
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goto put_bpmp;
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err_free_res:
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tegra194_cpufreq_free_resources();
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put_bpmp:
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tegra_bpmp_put(bpmp);
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return err;
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}
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static int tegra194_cpufreq_remove(struct platform_device *pdev)
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{
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cpufreq_unregister_driver(&tegra194_cpufreq_driver);
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tegra194_cpufreq_free_resources();
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return 0;
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}
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static const struct of_device_id tegra194_cpufreq_of_match[] = {
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{ .compatible = "nvidia,tegra194-ccplex", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, tegra194_cpufreq_of_match);
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static struct platform_driver tegra194_ccplex_driver = {
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.driver = {
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.name = "tegra194-cpufreq",
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.of_match_table = tegra194_cpufreq_of_match,
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},
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.probe = tegra194_cpufreq_probe,
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.remove = tegra194_cpufreq_remove,
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};
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module_platform_driver(tegra194_ccplex_driver);
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MODULE_AUTHOR("Mikko Perttunen <mperttunen@nvidia.com>");
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MODULE_AUTHOR("Sumit Gupta <sumitg@nvidia.com>");
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MODULE_DESCRIPTION("NVIDIA Tegra194 cpufreq driver");
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MODULE_LICENSE("GPL v2");
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