linux/drivers/cpufreq/tegra194-cpufreq.c
Mikko Perttunen c2ace21f93 cpufreq: tegra186/tegra194: Handle errors in BPMP response
The return value from tegra_bpmp_transfer indicates the success or
failure of the IPC transaction with BPMP. If the transaction
succeeded, we also need to check the actual command's result code.
Add code to do this.

While at it, explicitly handle missing CPU clusters, which can
occur on floorswept chips. This worked before as well, but
possibly only by accident.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2021-10-04 12:31:36 +05:30

438 lines
12 KiB
C

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