Re: [PATCH v5 2/2] cpufreq: qcom-hw: Add support for QCOM cpufreq HW driver

From: Taniya Das
Date: Mon Jul 16 2018 - 22:50:25 EST


Hello Evan,

Thank you for testing the patch.

On 7/17/2018 4:32 AM, Evan Green wrote:
Hi Taniya,
On Thu, Jul 12, 2018 at 11:06 AM Taniya Das <tdas@xxxxxxxxxxxxxx> wrote:

The CPUfreq HW present in some QCOM chipsets offloads the steps necessary
for changing the frequency of CPUs. The driver implements the cpufreq
driver interface for this hardware engine.

Signed-off-by: Saravana Kannan <skannan@xxxxxxxxxxxxxx>
Signed-off-by: Taniya Das <tdas@xxxxxxxxxxxxxx>
---
drivers/cpufreq/Kconfig.arm | 10 ++
drivers/cpufreq/Makefile | 1 +
drivers/cpufreq/qcom-cpufreq-hw.c | 344 ++++++++++++++++++++++++++++++++++++++
3 files changed, 355 insertions(+)
create mode 100644 drivers/cpufreq/qcom-cpufreq-hw.c

...
diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
new file mode 100644
index 0000000..fa25a95
--- /dev/null
+++ b/drivers/cpufreq/qcom-cpufreq-hw.c
...
+static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
+{
+ struct cpufreq_qcom *c;
+
+ c = qcom_freq_domain_map[policy->cpu];
+ if (!c) {
+ pr_err("No scaling support for CPU%d\n", policy->cpu);
+ return -ENODEV;
+ }
+
+ cpumask_copy(policy->cpus, &c->related_cpus);
+
+ policy->fast_switch_possible = true;
+ policy->freq_table = c->table;
+ policy->driver_data = c;
+
+ return 0;
I haven't looked at this driver in detail, but I have tested it.
Instead of the line above, I needed:

return cpufreq_table_validate_and_show(policy, c->table);

Without this the framework thinks that the min and max frequencies are
zero, and then you get a warning about an invalid table. I also
removed "policy->freq_table = c->table", since validate_and_show does
this.
-Evan


The API is no longer supported,

https://patchwork.kernel.org/patch/10320897/

If you are using the 4.14 kernel, you do need to replace

-policy->freq_table = c->table;
+cpufreq_table_validate_and_show(policy, c->table);

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