From: Sumit Gupta <sumitg@nvidia.com>
To: <viresh.kumar@linaro.org>, <rjw@rjwysocki.net>,
<sudeep.holla@arm.com>, <thierry.reding@gmail.com>,
<jonathanh@nvidia.com>, <linux-pm@vger.kernel.org>,
<linux-tegra@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>
Cc: <ksitaraman@nvidia.com>, <bbasu@nvidia.com>, <sumitg@nvidia.com>
Subject: [PATCH v2 1/2] cpufreq: tegra194: get consistent cpuinfo_cur_freq
Date: Thu, 8 Oct 2020 18:31:05 +0530 [thread overview]
Message-ID: <1602162066-26442-2-git-send-email-sumitg@nvidia.com> (raw)
In-Reply-To: <1602162066-26442-1-git-send-email-sumitg@nvidia.com>
Frequency returned by 'cpuinfo_cur_freq' using counters is not fixed
and keeps changing slightly. This change returns a consistent value
from freq_table. If the reconstructed frequency has acceptable delta
from the last written value, then return the frequency corresponding
to the last written ndiv value from freq_table. Otherwise, print a
warning and return the reconstructed freq.
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
---
drivers/cpufreq/tegra194-cpufreq.c | 71 +++++++++++++++++++++++++++++++++-----
1 file changed, 62 insertions(+), 9 deletions(-)
diff --git a/drivers/cpufreq/tegra194-cpufreq.c b/drivers/cpufreq/tegra194-cpufreq.c
index e1d931c..d250e49 100644
--- a/drivers/cpufreq/tegra194-cpufreq.c
+++ b/drivers/cpufreq/tegra194-cpufreq.c
@@ -180,9 +180,70 @@ static unsigned int tegra194_get_speed_common(u32 cpu, u32 delay)
return (rate_mhz * KHZ); /* in KHz */
}
+static void get_cpu_ndiv(void *ndiv)
+{
+ u64 ndiv_val;
+
+ asm volatile("mrs %0, s3_0_c15_c0_4" : "=r" (ndiv_val) : );
+
+ *(u64 *)ndiv = ndiv_val;
+}
+
+static void set_cpu_ndiv(void *data)
+{
+ struct cpufreq_frequency_table *tbl = data;
+ u64 ndiv_val = (u64)tbl->driver_data;
+
+ asm volatile("msr s3_0_c15_c0_4, %0" : : "r" (ndiv_val));
+}
+
static unsigned int tegra194_get_speed(u32 cpu)
{
- return tegra194_get_speed_common(cpu, US_DELAY);
+ struct tegra194_cpufreq_data *data = cpufreq_get_driver_data();
+ struct cpufreq_frequency_table *pos;
+ unsigned int rate;
+ u64 ndiv;
+ int ret;
+ u32 cl;
+
+ if (!cpu_online(cpu))
+ return -EINVAL;
+
+ smp_call_function_single(cpu, get_cpu_cluster, &cl, true);
+
+ if (cl >= data->num_clusters)
+ return -EINVAL;
+
+ /* reconstruct actual cpu freq using counters */
+ rate = tegra194_get_speed_common(cpu, US_DELAY);
+
+ /* get last written ndiv value */
+ ret = smp_call_function_single(cpu, get_cpu_ndiv, &ndiv, true);
+ if (ret) {
+ pr_err("cpufreq: Failed to get ndiv for CPU%d, ret:%d\n",
+ cpu, ret);
+ return rate;
+ }
+
+ /*
+ * If the reconstructed frequency has acceptable delta from
+ * the last written value, then return freq corresponding
+ * to the last written ndiv value from freq_table. This is
+ * done to return consistent value.
+ */
+ cpufreq_for_each_valid_entry(pos, data->tables[cl]) {
+ if (pos->driver_data != ndiv)
+ continue;
+
+ if (abs(pos->frequency - rate) > 115200) {
+ pr_warn("cpufreq: cpu%d,cur:%u,set:%u,set ndiv:%llu\n",
+ cpu, rate, pos->frequency, ndiv);
+ } else {
+ rate = pos->frequency;
+ }
+ break;
+ }
+ return rate;
}
static int tegra194_cpufreq_init(struct cpufreq_policy *policy)
@@ -209,14 +270,6 @@ static int tegra194_cpufreq_init(struct cpufreq_policy *policy)
return 0;
}
-static void set_cpu_ndiv(void *data)
-{
- struct cpufreq_frequency_table *tbl = data;
- u64 ndiv_val = (u64)tbl->driver_data;
-
- asm volatile("msr s3_0_c15_c0_4, %0" : : "r" (ndiv_val));
-}
-
static int tegra194_cpufreq_set_target(struct cpufreq_policy *policy,
unsigned int index)
{
--
2.7.4
next prev parent reply other threads:[~2020-10-08 13:01 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-08 13:01 [PATCH v2 0/2] Tegra194 cpufreq driver misc changes Sumit Gupta
2020-10-08 13:01 ` Sumit Gupta [this message]
2020-10-12 5:22 ` [PATCH v2 1/2] cpufreq: tegra194: get consistent cpuinfo_cur_freq Viresh Kumar
2020-10-12 16:34 ` Sumit Gupta
2020-10-08 13:01 ` [PATCH v2 2/2] cpufreq: tegra194: Fix unlisted boot freq warning Sumit Gupta
2020-10-12 6:13 ` Viresh Kumar
2020-10-12 17:06 ` Sumit Gupta
2020-10-13 5:13 ` Viresh Kumar
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