From: Todd Poynor <toddpoynor@xxxxxxxxxx>
Add initcall_debug logs for the amount of time taken by each OF platform
bus device create call. For example:
of platform device create /reserved-memory/ramoops@a3800000 took
3255 usecs
initcall_debug already reports the total of all such device creates
as a single entry for function of_platform_default_populate_init (or
similar, depending on the board). The new logs help identify which of
the potentially hundreds of device inits take significant amounts of
time.
Signed-off-by: Todd Poynor <toddpoynor@xxxxxxxxxx>
---
drivers/of/platform.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
Note it's likely only a few devices take significant lengths of time to
init, whereas there may be hundreds of uninteresting cases also logged.
Adding a threshold for reporting might be desirable, although for boot
time sleuthing it's probably fine to generate a ton of output and narrow
down the points of interest with tools.
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 6925d993e1f0..eeb4c595f43c 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -14,6 +14,7 @@
#include <linux/amba/bus.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
+#include <linux/init.h>
#include <linux/slab.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
@@ -159,6 +160,19 @@ struct platform_device *of_device_alloc(struct device_node *np,
}
EXPORT_SYMBOL(of_device_alloc);
+static void of_platform_log_inittime(struct device_node *node,
+ ktime_t starttime)
+{
+ ktime_t delta, endtime;
+ unsigned long long duration;
+
+ endtime = ktime_get();
+ delta = ktime_sub(endtime, starttime);
+ duration = (unsigned long long) ktime_to_ns(delta) >> 10;
+ pr_debug("of platform device create %s took %lld usecs\n",
+ node->full_name, duration);
+}
+
/**
* of_platform_device_create_pdata - Alloc, initialize and register an of_device
* @np: pointer to node to create device for
@@ -176,6 +190,8 @@ static struct platform_device *of_platform_device_create_pdata(
struct device *parent)
{
struct platform_device *dev;
+ ktime_t starttime = 0;
+ int ret;
if (!of_device_is_available(np) ||
of_node_test_and_set_flag(np, OF_POPULATED))
@@ -187,9 +203,14 @@ static struct platform_device *of_platform_device_create_pdata(
dev->dev.bus = &platform_bus_type;
dev->dev.platform_data = platform_data;
+ if (initcall_debug)
+ starttime = ktime_get();
of_msi_configure(&dev->dev, dev->dev.of_node);
+ ret = of_device_add(dev);
+ if (initcall_debug)
+ of_platform_log_inittime(np, starttime);
- if (of_device_add(dev) != 0) {
+ if (ret != 0) {
platform_device_put(dev);
goto err_clear_flag;
}
@@ -352,6 +373,7 @@ static int of_platform_bus_create(struct device_node *bus,
struct platform_device *dev;
const char *bus_id = NULL;
void *platform_data = NULL;
+ ktime_t starttime = 0;
int rc = 0;
/* Make sure it has a compatible property */
@@ -384,7 +406,11 @@ static int of_platform_bus_create(struct device_node *bus,
* Don't return an error here to keep compatibility with older
* device tree files.
*/
+ if (initcall_debug)
+ starttime = ktime_get();
of_amba_device_create(bus, bus_id, platform_data, parent);
+ if (initcall_debug)
+ of_platform_log_inittime(bus, starttime);
return 0;
}
--
2.18.0.rc1.244.gcf134e6275-goog
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