The ECME sends thermal messages with a maximum and minimum allowed
frequency when the SoC status reaches certain trip points known to the
ECME. Use a notifier function to capture those messages and pass them
to a work-queued function that can trigger a policy re-evaluation by
cpufreq, capping the allowable frequencies.
The core of the policy adjusting code was taken from
drivers/thermal/cpu_cooling.c.
Signed-off-by: Mark Langsdorf <mark.langsd...@calxeda.com>
---
drivers/cpufreq/highbank-cpufreq.c | 117 +++++++++++++++++++++++++++++++++++++
1 file changed, 117 insertions(+)
diff --git a/drivers/cpufreq/highbank-cpufreq.c
b/drivers/cpufreq/highbank-cpufreq.c
index b61b5a3..f0521d3 100644
--- a/drivers/cpufreq/highbank-cpufreq.c
+++ b/drivers/cpufreq/highbank-cpufreq.c
@@ -17,15 +17,32 @@
#include <linux/module.h>
#include <linux/clk.h>
#include <linux/cpu.h>
+#include <linux/cpufreq.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/mailbox.h>
#include <linux/platform_device.h>
+#include <linux/cpumask.h>
+#include <linux/workqueue.h>
#define HB_CPUFREQ_CHANGE_NOTE 0x80000001
+#define HB_CPUFREQ_HEALTH_NOTE 0x00001001
+#define HB_CPUFREQ_TPS_REPORT 1
#define HB_CPUFREQ_IPC_LEN 7
#define HB_CPUFREQ_VOLT_RETRIES 15
+#define NOTIFY_INVALID NULL
+
+struct hb_notify_device {
+ unsigned long max_freq;
+ unsigned long min_freq;
+ unsigned long thermal_state;
+ struct cpumask *allowed_cpus;
+};
+
+static struct hb_notify_device hb_records, *notify_device = NOTIFY_INVALID;
+static struct work_struct hb_thermal_wq;
+
static int hb_voltage_change(unsigned int freq)
{
u32 msg[HB_CPUFREQ_IPC_LEN] = {HB_CPUFREQ_CHANGE_NOTE, freq / 1000000};
@@ -33,6 +50,89 @@ static int hb_voltage_change(unsigned int freq)
return pl320_ipc_transmit(msg);
}
+static int hb_thermal_cpufreq_notify(struct notifier_block *nb,
+ unsigned long event, void *data)
+{
+ struct cpufreq_policy *policy = data;
+ unsigned long max_freq = 0, min_freq = 0;
+
+ if (event != CPUFREQ_ADJUST || notify_device == NOTIFY_INVALID)
+ return 0;
+
+ if (cpumask_test_cpu(policy->cpu, notify_device->allowed_cpus)) {
+ max_freq = notify_device->max_freq;
+ min_freq = notify_device->min_freq;
+ }
+
+ /* Never exceed user_policy.max */
+ if (max_freq > policy->user_policy.max)
+ max_freq = policy->user_policy.max;
+ if (min_freq < policy->user_policy.min)
+ min_freq = policy->user_policy.min;
+
+ if ((policy->max != max_freq) || (policy->min != min_freq))
+ cpufreq_verify_within_limits(policy, min_freq, max_freq);
+
+ return 0;
+}
+
+static struct notifier_block hb_thermal_cpufreq_nb = {
+ .notifier_call = hb_thermal_cpufreq_notify,
+};
+
+/*
+ * We can't call cpufreq_adjust_policy from inside a notifier, so
+ * do it from inside a workqueue
+ */
+static void hb_thermal_wq_task(struct work_struct *work)
+{
+ unsigned int cpuid;
+ struct cpumask *mask = hb_records.allowed_cpus;
+
+ notify_device = &hb_records;
+
+ for_each_cpu(cpuid, mask) {
+ struct cpufreq_policy policy;
+ if (cpufreq_get_policy(&policy, cpuid) == 0) {
+ cpufreq_update_policy(cpuid);
+ break;
+ }
+ }
+ notify_device = NOTIFY_INVALID;
+}
+
+static int hb_thermal_tps_notify(struct notifier_block *nb,
+ unsigned long action, void *mailbox)
+{
+ unsigned long *data = (unsigned long *) mailbox;
+
+ if ((action != HB_CPUFREQ_HEALTH_NOTE) &&
+ (data[0] != HB_CPUFREQ_TPS_REPORT))
+ return 0;
+
+ /*
+ * If we're already at this thermal state, or if ECME isn't
+ * sending frequency data, there's nothing to do
+ */
+ if ((hb_records.thermal_state == data[1]) || !data[2] || !data[3])
+ return NOTIFY_DONE;
+
+ hb_records.thermal_state = data[1];
+ hb_records.min_freq = data[2];
+ hb_records.max_freq = data[3];
+ notify_device = &hb_records;
+
+ schedule_work(&hb_thermal_wq);
+
+ pr_warn("ECME TPS event: frequencies limited to %lu-%lu MHz\n",
+ hb_records.min_freq, hb_records.max_freq);
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block hb_thermal_tps_nb = {
+ .notifier_call = hb_thermal_tps_notify,
+};
+
static int hb_cpufreq_clk_notify(struct notifier_block *nb,
unsigned long action, void *hclk)
{
@@ -100,6 +200,23 @@ static int hb_cpufreq_driver_init(void)
goto out_put_node;
}
+ /*
+ * Set up thermal state notifications from ECME, but continue
+ * running even if they don't work.
+ */
+ ret = pl320_ipc_register_notifier(&hb_thermal_tps_nb);
+ if (!ret) {
+ ret = cpufreq_register_notifier(&hb_thermal_cpufreq_nb,
+ CPUFREQ_POLICY_NOTIFIER);
+ if (ret)
+ pl320_ipc_unregister_notifier(&hb_thermal_tps_nb);
+ else {
+ hb_records.allowed_cpus = (struct cpumask *)
+ cpu_possible_mask;
+ INIT_WORK(&hb_thermal_wq, hb_thermal_wq_task);
+ }
+ }
+
/* Instantiate cpufreq-cpu0 */
platform_device_register_full(&devinfo);
--
1.8.3.1
--
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