Re: [PATCH v5 4/5] cpufreq: qcom: Update the bandwidth levels on frequency change
From: Sibi Sankar
Date: Fri May 29 2020 - 07:31:24 EST
Hey Viresh,
Thanks for taking time to review the
series :)
On 2020-05-29 15:30, Viresh Kumar wrote:
On 28-05-20, 01:51, Sibi Sankar wrote:
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@xxxxxxxxxxxxxx>
---
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 | 77
++++++++++++++++++++++++++++++-
1 file changed, 75 insertions(+), 2 deletions(-)
diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c
b/drivers/cpufreq/qcom-cpufreq-hw.c
index fc92a8842e252..fbd73d106a3ae 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>
@@ -31,6 +32,52 @@
static unsigned long cpu_hw_rate, xo_rate;
static struct platform_device *global_pdev;
+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;
+
+ if (dev_pm_opp_adjust_voltage(cpu_dev, freq_hz, volt, volt, volt))
+ return dev_pm_opp_add(cpu_dev, freq_hz, volt);
What's going on here ? Why add OPP here ?
We update the voltage if opp were
initially added as part of
dev_pm_opp_of_add_table. However
if the cpu node does not have an
opp table associated with it, we
do a opp_add_v1 instead.
+
+ /* Enable the opp after voltage update */
+ return dev_pm_opp_enable(cpu_dev, freq_hz);
+}
+
+/* Check for optional interconnect paths on CPU0 */
+static int qcom_cpufreq_find_icc_paths(struct device *dev)
+{
+ struct device *cpu_dev;
+
+ cpu_dev = get_cpu_device(0);
+ if (!cpu_dev)
+ return -EPROBE_DEFER;
+
+ return dev_pm_opp_of_find_icc_paths(cpu_dev, NULL);
+}
+
open code this into the probe routine.
sure
static int qcom_cpufreq_hw_target_index(struct cpufreq_policy
*policy,
unsigned int index)
{
@@ -39,6 +86,8 @@ static int qcom_cpufreq_hw_target_index(struct
cpufreq_policy *policy,
writel_relaxed(index, perf_state_reg);
+ qcom_cpufreq_set_bw(policy, freq);
+
arch_set_freq_scale(policy->related_cpus, freq,
policy->cpuinfo.max_freq);
return 0;
@@ -88,12 +137,30 @@ static int qcom_cpufreq_hw_read_lut(struct device
*cpu_dev,
{
u32 data, src, lval, i, core_count, prev_freq = 0, freq;
u32 volt;
+ u64 rate;
struct cpufreq_frequency_table *table;
+ struct device_node *opp_table_np, *np;
+ 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 */
+ opp_table_np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
+ for_each_available_child_of_node(opp_table_np, np) {
+ ret = of_property_read_u64(np, "opp-hz", &rate);
No way, please use dev_pm_opp_find_freq_*() here instead to grab OPPs
one by one.
sure I'll use a dev_pm_opp_find_freq_ceil
loop to do the same :P
+ if (!ret)
+ dev_pm_opp_disable(cpu_dev, rate);
+ }
+ of_node_put(opp_table_np);
+ } else if (ret != -ENODEV) {
+ dev_err(cpu_dev, "Invalid OPP table in Device tree\n");
+ return ret;
+ }
Rather put this in the if (ret) block and so the else part doesn't
need extra indentation.
https://patchwork.kernel.org/patch/11573905/
I'll need to enable fast_switch
when the device does not have a
opp-table associated with it or
throw a error when an improper
table is specified. If a table
with bw values is specified, we
disable fast switch and enable
scaling.
+
for (i = 0; i < LUT_MAX_ENTRIES; i++) {
data = readl_relaxed(base + REG_FREQ_LUT +
i * LUT_ROW_SIZE);
@@ -112,7 +179,7 @@ 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 +200,8 @@ 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;
--
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