[PATCH v6 4/5] cpufreq: qcom: Update the bandwidth levels on frequency change

Sibi Sankar
2020-06-05T21:34:23Z

Add support to parse optional OPP table attached to the cpu node when
the OPP bandwidth values are populated. This allows for scaling of
DDR/L3 bandwidth levels with frequency change.

Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
---

v6:
* Add global flag to distinguish between voltage update and opp add.
Use the same flag before trying to scale ddr/l3 bw [Viresh]
* Use dev_pm_opp_find_freq_ceil to grab all opps [Viresh]
* Move dev_pm_opp_of_find_icc_paths into probe [Viresh]

v5:
* Use dev_pm_opp_adjust_voltage instead [Viresh]
* Misc cleanup

v4:
* Split fast switch disable into another patch [Lukasz]

drivers/cpufreq/qcom-cpufreq-hw.c | 82 ++++++++++++++++++++++++++++++-
1 file changed, 80 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
index fc92a8842e252..8fa6ab6e0e4b6 100644
--- a/drivers/cpufreq/qcom-cpufreq-hw.c
+++ b/drivers/cpufreq/qcom-cpufreq-hw.c
@@ -6,6 +6,7 @@
#include <linux/bitfield.h>
#include <linux/cpufreq.h>
#include <linux/init.h>
+#include <linux/interconnect.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_address.h>
@@ -30,6 +31,48 @@

static unsigned long cpu_hw_rate, xo_rate;
static struct platform_device *global_pdev;
+static bool icc_scaling_enabled;
+
+static int qcom_cpufreq_set_bw(struct cpufreq_policy *policy,
+ unsigned long freq_khz)
+{
+ unsigned long freq_hz = freq_khz * 1000;
+ struct dev_pm_opp *opp;
+ struct device *dev;
+ int ret;
+
+ dev = get_cpu_device(policy->cpu);
+ if (!dev)
+ return -ENODEV;
+
+ opp = dev_pm_opp_find_freq_exact(dev, freq_hz, true);
+ if (IS_ERR(opp))
+ return PTR_ERR(opp);
+
+ ret = dev_pm_opp_set_bw(dev, opp);
+ dev_pm_opp_put(opp);
+ return ret;
+}
+
+static int qcom_cpufreq_update_opp(struct device *cpu_dev,
+ unsigned long freq_khz,
+ unsigned long volt)
+{
+ unsigned long freq_hz = freq_khz * 1000;
+ int ret;
+
+ /* Skip voltage update if the opp table is not available */
+ if (!icc_scaling_enabled)
+ return dev_pm_opp_add(cpu_dev, freq_hz, volt);
+
+ ret = dev_pm_opp_adjust_voltage(cpu_dev, freq_hz, volt, volt, volt);
+ if (ret) {
+ dev_err(cpu_dev, "Voltage update failed freq=%ld\n", freq_khz);
+ return ret;
+ }
+
+ return dev_pm_opp_enable(cpu_dev, freq_hz);
+}

static int qcom_cpufreq_hw_target_index(struct cpufreq_policy *policy,
unsigned int index)
@@ -39,6 +82,9 @@ static int qcom_cpufreq_hw_target_index(struct cpufreq_policy *policy,

writel_relaxed(index, perf_state_reg);

+ if (icc_scaling_enabled)
+ qcom_cpufreq_set_bw(policy, freq);
+
arch_set_freq_scale(policy->related_cpus, freq,
policy->cpuinfo.max_freq);
return 0;
@@ -89,11 +135,31 @@ static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
u32 data, src, lval, i, core_count, prev_freq = 0, freq;
u32 volt;
struct cpufreq_frequency_table *table;
+ struct dev_pm_opp *opp;
+ unsigned long rate;
+ int ret;

table = kcalloc(LUT_MAX_ENTRIES + 1, sizeof(*table), GFP_KERNEL);
if (!table)
return -ENOMEM;

+ ret = dev_pm_opp_of_add_table(cpu_dev);
+ if (!ret) {
+ /* Disable all opps and cross-validate against LUT */
+ icc_scaling_enabled = true;
+ for (rate = 0; ; rate++) {
+ opp = dev_pm_opp_find_freq_ceil(cpu_dev, &rate);
+ if (IS_ERR(opp))
+ break;
+
+ dev_pm_opp_put(opp);
+ dev_pm_opp_disable(cpu_dev, rate);
+ }
+ } else if (ret != -ENODEV) {
+ dev_err(cpu_dev, "Invalid opp table in device tree\n");
+ return ret;
+ }
+
for (i = 0; i < LUT_MAX_ENTRIES; i++) {
data = readl_relaxed(base + REG_FREQ_LUT +
i * LUT_ROW_SIZE);
@@ -112,7 +178,7 @@ static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,

if (freq != prev_freq && core_count != LUT_TURBO_IND) {
table[i].frequency = freq;
- dev_pm_opp_add(cpu_dev, freq * 1000, volt);
+ qcom_cpufreq_update_opp(cpu_dev, freq, volt);
dev_dbg(cpu_dev, "index=%d freq=%d, core_count %d\n", i,
freq, core_count);
} else if (core_count == LUT_TURBO_IND) {
@@ -133,7 +199,8 @@ static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
if (prev->frequency == CPUFREQ_ENTRY_INVALID) {
prev->frequency = prev_freq;
prev->flags = CPUFREQ_BOOST_FREQ;
- dev_pm_opp_add(cpu_dev, prev_freq * 1000, volt);
+ qcom_cpufreq_update_opp(cpu_dev, prev_freq,
+ volt);
}

break;
@@ -254,6 +321,7 @@ static int qcom_cpufreq_hw_cpu_exit(struct cpufreq_policy *policy)
void __iomem *base = policy->driver_data - REG_PERF_STATE;

dev_pm_opp_remove_all_dynamic(cpu_dev);
+ dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
kfree(policy->freq_table);
devm_iounmap(&global_pdev->dev, base);

@@ -282,6 +350,7 @@ static struct cpufreq_driver cpufreq_qcom_hw_driver = {

static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev)
{
+ struct device *cpu_dev;
struct clk *clk;
int ret;

@@ -301,6 +370,15 @@ static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev)

global_pdev = pdev;

+ /* Check for optional interconnect paths on CPU0 */
+ cpu_dev = get_cpu_device(0);
+ if (!cpu_dev)
+ return -EPROBE_DEFER;
+
+ ret = dev_pm_opp_of_find_icc_paths(cpu_dev, NULL);
+ if (ret)
+ return ret;
+
ret = cpufreq_register_driver(&cpufreq_qcom_hw_driver);
if (ret)
dev_err(&pdev->dev, "CPUFreq HW driver failed to register\n");
--
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