From: Saravana Kannan <saravanak@google.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Linus Walleij <linus.walleij@linaro.org>,
Bartosz Golaszewski <brgl@bgdev.pl>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Magnus Damm <magnus.damm@gmail.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Daniel Scally <djrscally@gmail.com>,
Heikki Krogerus <heikki.krogerus@linux.intel.com>,
Sakari Ailus <sakari.ailus@linux.intel.com>,
Len Brown <lenb@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>,
Abel Vesa <abel.vesa@linaro.org>,
Alexander Stein <alexander.stein@ew.tq-group.com>,
Tony Lindgren <tony@atomide.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
John Stultz <jstultz@google.com>,
Doug Anderson <dianders@chromium.org>,
Guenter Roeck <linux@roeck-us.net>,
kernel-team@android.com, linux-kernel@vger.kernel.org,
linux-gpio@vger.kernel.org, devicetree@vger.kernel.org,
linux-renesas-soc@vger.kernel.org, linux-acpi@vger.kernel.org
Subject: [PATCH v1 6/9] driver core: fw_devlink: Allow marking a fwnode link as being part of a cycle
Date: Tue, 9 Aug 2022 23:00:35 -0700 [thread overview]
Message-ID: <20220810060040.321697-7-saravanak@google.com> (raw)
In-Reply-To: <20220810060040.321697-1-saravanak@google.com>
To improve detection and handling of dependency cycles, we need to be
able to mark fwnode links as being part of cycles. fwnode links marked
as being part of a cycle should not block their consumers from probing.
Signed-off-by: Saravana Kannan <saravanak@google.com>
---
drivers/base/core.c | 41 +++++++++++++++++++++++++++++++++++------
include/linux/fwnode.h | 11 ++++++++++-
2 files changed, 45 insertions(+), 7 deletions(-)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index afa660d14172..0ec2c4d5ffaa 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -125,6 +125,19 @@ static void __fwnode_link_del(struct fwnode_link *link)
kfree(link);
}
+/**
+ * __fwnode_link_cycle - Mark a fwnode link as being part of a cycle.
+ * @link: the fwnode_link to be marked
+ *
+ * The fwnode_link_lock needs to be held when this function is called.
+ */
+static void __fwnode_link_cycle(struct fwnode_link *link)
+{
+ pr_debug("%pfwf: Relaxing link with %pfwf\n",
+ link->consumer, link->supplier);
+ link->flags |= FWLINK_FLAG_CYCLE;
+}
+
/**
* fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
* @fwnode: fwnode whose supplier links need to be deleted
@@ -1040,6 +1053,23 @@ static bool dev_is_best_effort(struct device *dev)
(dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT));
}
+static struct fwnode_handle *fwnode_links_check_suppliers(
+ struct fwnode_handle *fwnode)
+{
+ struct fwnode_link *link;
+
+ if (!fwnode || fw_devlink_is_permissive())
+ return NULL;
+
+ list_for_each_entry(link, &fwnode->suppliers, c_hook) {
+ if (link->flags & FWLINK_FLAG_CYCLE)
+ continue;
+ return link->supplier;
+ }
+
+ return NULL;
+}
+
/**
* device_links_check_suppliers - Check presence of supplier drivers.
* @dev: Consumer device.
@@ -1067,11 +1097,8 @@ int device_links_check_suppliers(struct device *dev)
* probe.
*/
mutex_lock(&fwnode_link_lock);
- if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
- !fw_devlink_is_permissive()) {
- sup_fw = list_first_entry(&dev->fwnode->suppliers,
- struct fwnode_link,
- c_hook)->supplier;
+ sup_fw = fwnode_links_check_suppliers(dev->fwnode);
+ if (sup_fw) {
if (!dev_is_best_effort(dev)) {
fwnode_ret = -EPROBE_DEFER;
dev_err_probe(dev, -EPROBE_DEFER,
@@ -1260,7 +1287,9 @@ static ssize_t waiting_for_supplier_show(struct device *dev,
bool val;
device_lock(dev);
- val = !list_empty(&dev->fwnode->suppliers);
+ mutex_lock(&fwnode_link_lock);
+ val = !!fwnode_links_check_suppliers(dev->fwnode);
+ mutex_unlock(&fwnode_link_lock);
device_unlock(dev);
return sysfs_emit(buf, "%u\n", val);
}
diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h
index 89b9bdfca925..fdf2ee0285b7 100644
--- a/include/linux/fwnode.h
+++ b/include/linux/fwnode.h
@@ -18,7 +18,7 @@ struct fwnode_operations;
struct device;
/*
- * fwnode link flags
+ * fwnode flags
*
* LINKS_ADDED: The fwnode has already be parsed to add fwnode links.
* NOT_DEVICE: The fwnode will never be populated as a struct device.
@@ -36,6 +36,7 @@ struct device;
#define FWNODE_FLAG_INITIALIZED BIT(2)
#define FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD BIT(3)
#define FWNODE_FLAG_BEST_EFFORT BIT(4)
+#define FWNODE_FLAG_VISITED BIT(5)
struct fwnode_handle {
struct fwnode_handle *secondary;
@@ -46,11 +47,19 @@ struct fwnode_handle {
u8 flags;
};
+/*
+ * fwnode link flags
+ *
+ * CYCLE: The fwnode link is part of a cycle. Don't defer probe.
+ */
+#define FWLINK_FLAG_CYCLE BIT(0)
+
struct fwnode_link {
struct fwnode_handle *supplier;
struct list_head s_hook;
struct fwnode_handle *consumer;
struct list_head c_hook;
+ u8 flags;
};
/**
--
2.37.1.559.g78731f0fdb-goog
next prev parent reply other threads:[~2022-08-10 6:02 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-10 6:00 [PATCH v1 0/9] fw_devlink improvements Saravana Kannan
2022-08-10 6:00 ` [PATCH v1 1/9] driver core: fw_devlink: Don't purge child fwnode's consumer links Saravana Kannan
2022-08-10 6:00 ` [PATCH v1 2/9] driver core: fw_devlink: Improve check for fwnode with no device/driver Saravana Kannan
2022-08-10 6:00 ` [PATCH v1 3/9] soc: renesas: Move away from using OF_POPULATED for fw_devlink Saravana Kannan
2022-08-10 6:00 ` [PATCH v1 4/9] gpiolib: Clear the gpio_device's fwnode initialized flag before adding Saravana Kannan
2022-08-15 9:57 ` Bartosz Golaszewski
2022-08-10 6:00 ` [PATCH v1 5/9] driver core: fw_devlink: Add DL_FLAG_CYCLE support to device links Saravana Kannan
2022-08-10 6:00 ` Saravana Kannan [this message]
2022-08-10 6:00 ` [PATCH v1 7/9] driver core: fw_devlink: Consolidate device link flag computation Saravana Kannan
2022-08-10 6:00 ` [PATCH v1 8/9] driver core: fw_devlink: Make cycle detection more robust Saravana Kannan
2022-08-10 6:00 ` [PATCH v1 9/9] of: property: Simplify of_link_to_phandle() Saravana Kannan
2022-08-12 9:47 ` Tony Lindgren
2022-08-13 0:37 ` Saravana Kannan
2022-08-15 10:31 ` Tony Lindgren
2022-08-15 21:00 ` Saravana Kannan
2022-08-12 9:49 ` [PATCH v1 0/9] fw_devlink improvements Tony Lindgren
2022-08-13 0:51 ` Saravana Kannan
2022-08-15 10:33 ` Tony Lindgren
2022-08-15 18:23 ` Saravana Kannan
2022-08-18 7:05 ` Tony Lindgren
2022-08-18 15:00 ` Greg Kroah-Hartman
2022-08-14 5:59 ` Saravana Kannan
2022-08-15 10:17 ` Naresh Kamboju
2022-08-15 11:01 ` Abel Vesa
2022-08-15 18:23 ` Saravana Kannan
2022-08-15 12:39 ` Alexander Stein
2022-08-15 19:17 ` Saravana Kannan
2022-08-15 20:56 ` Saravana Kannan
2022-08-16 7:17 ` Alexander Stein
2022-08-16 18:51 ` Saravana Kannan
2022-08-16 7:17 ` Alexander Stein
2022-08-15 13:52 ` Sudeep Holla
2022-08-17 13:01 ` Geert Uytterhoeven
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