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

v7:
* Fixup comments for correctness [Matthias]
* Initialize icc_scaling_enabled to false [Matthias]
* Make use of the increased per line character limit [Matthias]

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 | 83 ++++++++++++++++++++++++++++++-
1 file changed, 81 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
index fc92a8842e252..aaf98333d37da 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 +135,33 @@ 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 later */
+ 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;
+ } else {
+ icc_scaling_enabled = false;
+ }
+
for (i = 0; i < LUT_MAX_ENTRIES; i++) {
data = readl_relaxed(base + REG_FREQ_LUT +
i * LUT_ROW_SIZE);
@@ -112,7 +180,7 @@ 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 +201,7 @@ 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 +322,7 @@ 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 +351,7 @@ 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 +371,15 @@ 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");
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
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