From: Saravana Kannan <saravanak@google.com>
To: Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Frank Rowand <frowand.list@gmail.com>
Cc: Saravana Kannan <saravanak@google.com>,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@android.com
Subject: [PATCH v1 1/5] of/platform: Speed up of_find_device_by_node()
Date: Thu, 23 May 2019 18:01:12 -0700 [thread overview]
Message-ID: <20190524010117.225219-2-saravanak@google.com> (raw)
In-Reply-To: <20190524010117.225219-1-saravanak@google.com>
Add a pointer from device tree node to the device created from it.
This allows us to find the device corresponding to a device tree node
without having to loop through all the platform devices.
However, fallback to looping through the platform devices to handle
any devices that might set their own of_node.
Signed-off-by: Saravana Kannan <saravanak@google.com>
---
drivers/of/platform.c | 20 +++++++++++++++++++-
include/linux/of.h | 3 +++
2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 04ad312fd85b..1115a8d80a33 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -42,6 +42,8 @@ static int of_dev_node_match(struct device *dev, void *data)
return dev->of_node == data;
}
+static DEFINE_SPINLOCK(of_dev_lock);
+
/**
* of_find_device_by_node - Find the platform_device associated with a node
* @np: Pointer to device tree node
@@ -55,7 +57,18 @@ struct platform_device *of_find_device_by_node(struct device_node *np)
{
struct device *dev;
- dev = bus_find_device(&platform_bus_type, NULL, np, of_dev_node_match);
+ /*
+ * Spinlock needed to make sure np->dev doesn't get freed between NULL
+ * check inside and kref count increment inside get_device(). This is
+ * achieved by grabbing the spinlock before setting np->dev = NULL in
+ * of_platform_device_destroy().
+ */
+ spin_lock(&of_dev_lock);
+ dev = get_device(np->dev);
+ spin_unlock(&of_dev_lock);
+ if (!dev)
+ dev = bus_find_device(&platform_bus_type, NULL, np,
+ of_dev_node_match);
return dev ? to_platform_device(dev) : NULL;
}
EXPORT_SYMBOL(of_find_device_by_node);
@@ -196,6 +209,7 @@ static struct platform_device *of_platform_device_create_pdata(
platform_device_put(dev);
goto err_clear_flag;
}
+ np->dev = &dev->dev;
return dev;
@@ -556,6 +570,10 @@ int of_platform_device_destroy(struct device *dev, void *data)
if (of_node_check_flag(dev->of_node, OF_POPULATED_BUS))
device_for_each_child(dev, NULL, of_platform_device_destroy);
+ /* Spinlock is needed for of_find_device_by_node() to work */
+ spin_lock(&of_dev_lock);
+ dev->of_node->dev = NULL;
+ spin_unlock(&of_dev_lock);
of_node_clear_flag(dev->of_node, OF_POPULATED);
of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
diff --git a/include/linux/of.h b/include/linux/of.h
index 0cf857012f11..f2b4912cbca1 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -48,6 +48,8 @@ struct property {
struct of_irq_controller;
#endif
+struct device;
+
struct device_node {
const char *name;
phandle phandle;
@@ -68,6 +70,7 @@ struct device_node {
unsigned int unique_id;
struct of_irq_controller *irq_trans;
#endif
+ struct device *dev; /* Device created from this node */
};
#define MAX_PHANDLE_ARGS 16
--
2.22.0.rc1.257.g3120a18244-goog
next prev parent reply other threads:[~2019-05-24 1:01 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-24 1:01 [PATCH v1 0/5] Solve postboot supplier cleanup and optimize probe ordering Saravana Kannan
2019-05-24 1:01 ` Saravana Kannan [this message]
2019-05-24 17:56 ` [PATCH v1 1/5] of/platform: Speed up of_find_device_by_node() Frank Rowand
2019-05-24 18:21 ` Saravana Kannan
2019-05-25 0:12 ` Frank Rowand
2019-06-11 14:51 ` Frank Rowand
2019-06-11 20:07 ` Saravana Kannan
2019-05-24 1:01 ` [PATCH v1 2/5] driver core: Add device links support for pending links to suppliers Saravana Kannan
2019-05-24 5:48 ` Greg Kroah-Hartman
2019-05-24 1:01 ` [PATCH v1 3/5] dt-bindings: Add depends-on property Saravana Kannan
2019-05-24 15:01 ` Mark Rutland
2019-05-24 22:09 ` Saravana Kannan
2019-05-24 1:01 ` [PATCH v1 4/5] of/platform: Add functional dependency link from "depends-on" property Saravana Kannan
2019-05-24 1:01 ` [PATCH v1 5/5] driver core: Add sync_state driver/bus callback Saravana Kannan
2019-05-24 5:48 ` Greg Kroah-Hartman
2019-05-24 5:52 ` [PATCH v1 0/5] Solve postboot supplier cleanup and optimize probe ordering Greg Kroah-Hartman
2019-05-25 2:17 ` Saravana Kannan
2019-05-24 13:04 ` Rob Herring
2019-05-24 21:51 ` Saravana Kannan
2019-05-24 17:49 ` Frank Rowand
2019-05-24 21:53 ` Saravana Kannan
2019-05-25 0:16 ` Frank Rowand
2019-05-25 0:22 ` Frank Rowand
2019-05-25 0:25 ` Frank Rowand
2019-05-25 2:08 ` Saravana Kannan
2019-05-25 2:40 ` Frank Rowand
2019-05-25 4:04 ` Saravana Kannan
2019-06-11 14:56 ` Frank Rowand
2019-06-11 20:19 ` Saravana Kannan
[not found] ` <CAGETcx8MY7Xhc4YjCcO9TH6X9Sse4Mg2Wi6vjau5T6d4C-itFQ@mail.gmail.com>
2019-05-29 20:02 ` Saravana Kannan
2019-05-31 23:27 ` David Collins
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