linux/drivers/cpufreq/tegra186-cpufreq.c
Viresh Kumar 5ae4a4b45d cpufreq: Remove CPUFREQ_STICKY flag
During cpufreq driver's registration, if the ->init() callback for all
the CPUs fail then there is not much point in keeping the driver around
as it will only account for more of unnecessary noise, for example
cpufreq core will try to suspend/resume the driver which never got
registered properly.

The removal of such a driver is avoided if the driver carries the
CPUFREQ_STICKY flag. This was added way back [1] in 2004 and perhaps no
one should ever need it now. A lot of drivers do set this flag, probably
because they just copied it from other drivers.

This was added earlier for some platforms [2] because their cpufreq
drivers were getting registered before the CPUs were registered with
subsys framework. And hence they used to fail.

The same isn't true anymore though. The current code flow in the kernel
is:

start_kernel()
-> kernel_init()
   -> kernel_init_freeable()
      -> do_basic_setup()
         -> driver_init()
            -> cpu_dev_init()
               -> subsys_system_register() //For CPUs

         -> do_initcalls()
            -> cpufreq_register_driver()

Clearly, the CPUs will always get registered with subsys framework
before any cpufreq driver can get probed. Remove the flag and update the
relevant drivers.

Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/include/linux/cpufreq.h?id=7cc9f0d9a1ab04cedc60d64fd8dcf7df224a3b4d # [1]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/arch/arm/mach-sa1100/cpu-sa1100.c?id=f59d3bbe35f6268d729f51be82af8325d62f20f5 # [2]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-02-04 19:23:20 +01:00

287 lines
6.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2017, NVIDIA CORPORATION. All rights reserved
*/
#include <linux/cpufreq.h>
#include <linux/dma-mapping.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <soc/tegra/bpmp.h>
#include <soc/tegra/bpmp-abi.h>
#define TEGRA186_NUM_CLUSTERS 2
#define EDVD_OFFSET_A57(core) ((SZ_64K * 6) + (0x20 + (core) * 0x4))
#define EDVD_OFFSET_DENVER(core) ((SZ_64K * 7) + (0x20 + (core) * 0x4))
#define EDVD_CORE_VOLT_FREQ_F_SHIFT 0
#define EDVD_CORE_VOLT_FREQ_F_MASK 0xffff
#define EDVD_CORE_VOLT_FREQ_V_SHIFT 16
struct tegra186_cpufreq_cpu {
unsigned int bpmp_cluster_id;
unsigned int edvd_offset;
};
static const struct tegra186_cpufreq_cpu tegra186_cpus[] = {
/* CPU0 - A57 Cluster */
{
.bpmp_cluster_id = 1,
.edvd_offset = EDVD_OFFSET_A57(0)
},
/* CPU1 - Denver Cluster */
{
.bpmp_cluster_id = 0,
.edvd_offset = EDVD_OFFSET_DENVER(0)
},
/* CPU2 - Denver Cluster */
{
.bpmp_cluster_id = 0,
.edvd_offset = EDVD_OFFSET_DENVER(1)
},
/* CPU3 - A57 Cluster */
{
.bpmp_cluster_id = 1,
.edvd_offset = EDVD_OFFSET_A57(1)
},
/* CPU4 - A57 Cluster */
{
.bpmp_cluster_id = 1,
.edvd_offset = EDVD_OFFSET_A57(2)
},
/* CPU5 - A57 Cluster */
{
.bpmp_cluster_id = 1,
.edvd_offset = EDVD_OFFSET_A57(3)
},
};
struct tegra186_cpufreq_cluster {
struct cpufreq_frequency_table *table;
u32 ref_clk_khz;
u32 div;
};
struct tegra186_cpufreq_data {
void __iomem *regs;
struct tegra186_cpufreq_cluster *clusters;
const struct tegra186_cpufreq_cpu *cpus;
};
static int tegra186_cpufreq_init(struct cpufreq_policy *policy)
{
struct tegra186_cpufreq_data *data = cpufreq_get_driver_data();
unsigned int cluster = data->cpus[policy->cpu].bpmp_cluster_id;
policy->freq_table = data->clusters[cluster].table;
policy->cpuinfo.transition_latency = 300 * 1000;
policy->driver_data = NULL;
return 0;
}
static int tegra186_cpufreq_set_target(struct cpufreq_policy *policy,
unsigned int index)
{
struct tegra186_cpufreq_data *data = cpufreq_get_driver_data();
struct cpufreq_frequency_table *tbl = policy->freq_table + index;
unsigned int edvd_offset = data->cpus[policy->cpu].edvd_offset;
u32 edvd_val = tbl->driver_data;
writel(edvd_val, data->regs + edvd_offset);
return 0;
}
static unsigned int tegra186_cpufreq_get(unsigned int cpu)
{
struct tegra186_cpufreq_data *data = cpufreq_get_driver_data();
struct tegra186_cpufreq_cluster *cluster;
struct cpufreq_policy *policy;
unsigned int edvd_offset, cluster_id;
u32 ndiv;
policy = cpufreq_cpu_get(cpu);
if (!policy)
return 0;
edvd_offset = data->cpus[policy->cpu].edvd_offset;
ndiv = readl(data->regs + edvd_offset) & EDVD_CORE_VOLT_FREQ_F_MASK;
cluster_id = data->cpus[policy->cpu].bpmp_cluster_id;
cluster = &data->clusters[cluster_id];
cpufreq_cpu_put(policy);
return (cluster->ref_clk_khz * ndiv) / cluster->div;
}
static struct cpufreq_driver tegra186_cpufreq_driver = {
.name = "tegra186",
.flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
CPUFREQ_NEED_INITIAL_FREQ_CHECK,
.get = tegra186_cpufreq_get,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = tegra186_cpufreq_set_target,
.init = tegra186_cpufreq_init,
.attr = cpufreq_generic_attr,
};
static struct cpufreq_frequency_table *init_vhint_table(
struct platform_device *pdev, struct tegra_bpmp *bpmp,
struct tegra186_cpufreq_cluster *cluster, unsigned int cluster_id)
{
struct cpufreq_frequency_table *table;
struct mrq_cpu_vhint_request req;
struct tegra_bpmp_message msg;
struct cpu_vhint_data *data;
int err, i, j, num_rates = 0;
dma_addr_t phys;
void *virt;
virt = dma_alloc_coherent(bpmp->dev, sizeof(*data), &phys,
GFP_KERNEL);
if (!virt)
return ERR_PTR(-ENOMEM);
data = (struct cpu_vhint_data *)virt;
memset(&req, 0, sizeof(req));
req.addr = phys;
req.cluster_id = cluster_id;
memset(&msg, 0, sizeof(msg));
msg.mrq = MRQ_CPU_VHINT;
msg.tx.data = &req;
msg.tx.size = sizeof(req);
err = tegra_bpmp_transfer(bpmp, &msg);
if (err) {
table = ERR_PTR(err);
goto free;
}
for (i = data->vfloor; i <= data->vceil; i++) {
u16 ndiv = data->ndiv[i];
if (ndiv < data->ndiv_min || ndiv > data->ndiv_max)
continue;
/* Only store lowest voltage index for each rate */
if (i > 0 && ndiv == data->ndiv[i - 1])
continue;
num_rates++;
}
table = devm_kcalloc(&pdev->dev, num_rates + 1, sizeof(*table),
GFP_KERNEL);
if (!table) {
table = ERR_PTR(-ENOMEM);
goto free;
}
cluster->ref_clk_khz = data->ref_clk_hz / 1000;
cluster->div = data->pdiv * data->mdiv;
for (i = data->vfloor, j = 0; i <= data->vceil; i++) {
struct cpufreq_frequency_table *point;
u16 ndiv = data->ndiv[i];
u32 edvd_val = 0;
if (ndiv < data->ndiv_min || ndiv > data->ndiv_max)
continue;
/* Only store lowest voltage index for each rate */
if (i > 0 && ndiv == data->ndiv[i - 1])
continue;
edvd_val |= i << EDVD_CORE_VOLT_FREQ_V_SHIFT;
edvd_val |= ndiv << EDVD_CORE_VOLT_FREQ_F_SHIFT;
point = &table[j++];
point->driver_data = edvd_val;
point->frequency = (cluster->ref_clk_khz * ndiv) / cluster->div;
}
table[j].frequency = CPUFREQ_TABLE_END;
free:
dma_free_coherent(bpmp->dev, sizeof(*data), virt, phys);
return table;
}
static int tegra186_cpufreq_probe(struct platform_device *pdev)
{
struct tegra186_cpufreq_data *data;
struct tegra_bpmp *bpmp;
unsigned int i = 0, err;
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->clusters = devm_kcalloc(&pdev->dev, TEGRA186_NUM_CLUSTERS,
sizeof(*data->clusters), GFP_KERNEL);
if (!data->clusters)
return -ENOMEM;
data->cpus = tegra186_cpus;
bpmp = tegra_bpmp_get(&pdev->dev);
if (IS_ERR(bpmp))
return PTR_ERR(bpmp);
data->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(data->regs)) {
err = PTR_ERR(data->regs);
goto put_bpmp;
}
for (i = 0; i < TEGRA186_NUM_CLUSTERS; i++) {
struct tegra186_cpufreq_cluster *cluster = &data->clusters[i];
cluster->table = init_vhint_table(pdev, bpmp, cluster, i);
if (IS_ERR(cluster->table)) {
err = PTR_ERR(cluster->table);
goto put_bpmp;
}
}
tegra186_cpufreq_driver.driver_data = data;
err = cpufreq_register_driver(&tegra186_cpufreq_driver);
put_bpmp:
tegra_bpmp_put(bpmp);
return err;
}
static int tegra186_cpufreq_remove(struct platform_device *pdev)
{
cpufreq_unregister_driver(&tegra186_cpufreq_driver);
return 0;
}
static const struct of_device_id tegra186_cpufreq_of_match[] = {
{ .compatible = "nvidia,tegra186-ccplex-cluster", },
{ }
};
MODULE_DEVICE_TABLE(of, tegra186_cpufreq_of_match);
static struct platform_driver tegra186_cpufreq_platform_driver = {
.driver = {
.name = "tegra186-cpufreq",
.of_match_table = tegra186_cpufreq_of_match,
},
.probe = tegra186_cpufreq_probe,
.remove = tegra186_cpufreq_remove,
};
module_platform_driver(tegra186_cpufreq_platform_driver);
MODULE_AUTHOR("Mikko Perttunen <mperttunen@nvidia.com>");
MODULE_DESCRIPTION("NVIDIA Tegra186 cpufreq driver");
MODULE_LICENSE("GPL v2");