[PATCH v11 4/4] firmware: ti_sci: add CPU latency constraint management

Markus Schneider-Pargmann
2024-08-29T20:16:20Z

From: Kevin Hilman <khilman@baylibre.com>

During system-wide suspend, check if any of the CPUs have PM QoS
resume latency constraints set. If so, set TI SCI constraint.

TI SCI has a single system-wide latency constraint, so use the max of
any of the CPU latencies as the system-wide value.

Note: DM firmware clears all constraints at resume time, so
constraints need to be checked/updated/sent at each system suspend.

Co-developed-by: Vibhore Vardhan <vibhore@ti.com>
Signed-off-by: Vibhore Vardhan <vibhore@ti.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Tested-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
---
drivers/firmware/ti_sci.c | 24 +++++++++++++++++++++++-
1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index 8482b7077eef..d5d64e5ffbd7 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -10,6 +10,7 @@
#define pr_fmt(fmt) "%s: " fmt, __func__

#include <linux/bitmap.h>
+#include <linux/cpu.h>
#include <linux/debugfs.h>
#include <linux/export.h>
#include <linux/io.h>
@@ -20,6 +21,7 @@
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
+#include <linux/pm_qos.h>
#include <linux/property.h>
#include <linux/semaphore.h>
#include <linux/slab.h>
@@ -3669,7 +3671,27 @@ static int ti_sci_prepare_system_suspend(struct ti_sci_info *info)
static int __maybe_unused ti_sci_suspend(struct device *dev)
{
struct ti_sci_info *info = dev_get_drvdata(dev);
- int ret;
+ struct device *cpu_dev, *cpu_dev_max = NULL;
+ s32 val, cpu_lat = 0;
+ int i, ret;
+
+ if (info->fw_caps & MSG_FLAG_CAPS_LPM_DM_MANAGED) {
+ for_each_possible_cpu(i) {
+ cpu_dev = get_cpu_device(i);
+ val = dev_pm_qos_read_value(cpu_dev, DEV_PM_QOS_RESUME_LATENCY);
+ if (val != PM_QOS_RESUME_LATENCY_NO_CONSTRAINT) {
+ cpu_lat = max(cpu_lat, val);
+ cpu_dev_max = cpu_dev;
+ }
+ }
+ if (cpu_dev_max) {
+ dev_dbg(cpu_dev_max, "%s: sending max CPU latency=%u\n", __func__, cpu_lat);
+ ret = ti_sci_cmd_set_latency_constraint(&info->handle,
+ cpu_lat, TISCI_MSG_CONSTRAINT_SET);
+ if (ret)
+ return ret;
+ }
+ }

ret = ti_sci_prepare_system_suspend(info);
if (ret)
--
2.45.2