Re: [PATCH v11 4/4] firmware: ti_sci: add CPU latency constraint management
From: Nathan Chancellor <nathan@kernel.org>
Date: 2024-09-03 00:54:24
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Hi Markus, On Thu, Aug 29, 2024 at 10:16:05PM +0200, Markus Schneider-Pargmann wrote:
quoted hunk ↗ jump to hunk
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 <redacted> Signed-off-by: Vibhore Vardhan <redacted> Reviewed-by: Dhruva Gole <redacted> Signed-off-by: Dhruva Gole <redacted> Signed-off-by: Kevin Hilman <khilman@baylibre.com> Tested-by: Dhruva Gole <redacted> 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);
This change is now in -next as commit 458d22d2e064 ("firmware: ti_sci:
add CPU latency constraint management"), where it breaks the build
when this driver is built as a module because dev_pm_qos_read_value() is
not exported to modules:
ERROR: modpost: "dev_pm_qos_read_value" [drivers/firmware/ti_sci.ko] undefined!
Obviously exporting it would fix the build but sometimes that is
controversial, hence just the report.
+ 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