Re: [PATCH v4 01/18] fpga: bridge: support getting bridge from device

From: matthew . gerlach
Date: Wed Sep 13 2017 - 19:38:21 EST


Hi Alan,

Two minor nits below.

Matthew Gerlach

On Wed, 13 Sep 2017, Alan Tull wrote:

Add two functions for getting the FPGA bridge from the device
rather than device tree node. This is to enable writing code
that will support using FPGA bridges without device tree.
Rename one old function to make it clear that it is device
tree-ish. This leaves us with 3 functions for getting a bridge:

* fpga_bridge_get
Get the bridge given the device.

* fpga_bridges_get_to_list
Given the device, get the bridge and add it to a list.

* of_fpga_bridges_get_to_list
Renamed from priviously existing fpga_bridges_get_to_list.
Given the device node, get the bridge and add it to a list.

Signed-off-by: Alan Tull <atull@xxxxxxxxxx>
---
v2: use list_for_each_entry
static the bridge_list_lock
update copyright and author email
v3: no change to this patch in this version of patchset
v4: no change to this patch in this version of patchset
---
drivers/fpga/fpga-bridge.c | 110 +++++++++++++++++++++++++++++++--------
drivers/fpga/fpga-region.c | 11 ++--
include/linux/fpga/fpga-bridge.h | 7 ++-
3 files changed, 100 insertions(+), 28 deletions(-)

diff --git a/drivers/fpga/fpga-bridge.c b/drivers/fpga/fpga-bridge.c
index fcd2bd3..af6d97e 100644
--- a/drivers/fpga/fpga-bridge.c
+++ b/drivers/fpga/fpga-bridge.c
@@ -2,6 +2,7 @@
* FPGA Bridge Framework Driver
*
* Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
+ * Copyright (C) 2017 Intel Corporation
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
@@ -70,29 +71,12 @@ int fpga_bridge_disable(struct fpga_bridge *bridge)
}
EXPORT_SYMBOL_GPL(fpga_bridge_disable);

-/**
- * of_fpga_bridge_get - get an exclusive reference to a fpga bridge
- *
- * @np: node pointer of a FPGA bridge
- * @info: fpga image specific information
- *
- * Return fpga_bridge struct if successful.
- * Return -EBUSY if someone already has a reference to the bridge.
- * Return -ENODEV if @np is not a FPGA Bridge.
- */
-struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
- struct fpga_image_info *info)
-
+struct fpga_bridge *__fpga_bridge_get(struct device *dev,
+ struct fpga_image_info *info)

Should this be a static function?

I was recently told by mtd maintainers that function names prefixed with
__ should be avoided.


{
- struct device *dev;
struct fpga_bridge *bridge;
int ret = -ENODEV;

- dev = class_find_device(fpga_bridge_class, NULL, np,
- fpga_bridge_of_node_match);
- if (!dev)
- goto err_dev;
-
bridge = to_fpga_bridge(dev);
if (!bridge)
goto err_dev;
@@ -117,8 +101,58 @@ struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
put_device(dev);
return ERR_PTR(ret);
}
+
+/**
+ * of_fpga_bridge_get - get an exclusive reference to a fpga bridge
+ *
+ * @np: node pointer of a FPGA bridge
+ * @info: fpga image specific information
+ *
+ * Return fpga_bridge struct if successful.
+ * Return -EBUSY if someone already has a reference to the bridge.
+ * Return -ENODEV if @np is not a FPGA Bridge.
+ */
+struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
+ struct fpga_image_info *info)
+{
+ struct device *dev;
+
+ dev = class_find_device(fpga_bridge_class, NULL, np,
+ fpga_bridge_of_node_match);
+ if (!dev)
+ return ERR_PTR(-ENODEV);
+
+ return __fpga_bridge_get(dev, info);
+}
EXPORT_SYMBOL_GPL(of_fpga_bridge_get);

+static int fpga_bridge_dev_match(struct device *dev, const void *data)
+{
+ return dev->parent == data;
+}
+
+/**
+ * fpga_bridge_get - get an exclusive reference to a fpga bridge
+ * @dev: parent device that fpga bridge was registered with
+ *
+ * Given a device, get an exclusive reference to a fpga bridge.
+ *
+ * Return: fpga manager struct or IS_ERR() condition containing error code.
+ */
+struct fpga_bridge *fpga_bridge_get(struct device *dev,
+ struct fpga_image_info *info)
+{
+ struct device *bridge_dev;
+
+ bridge_dev = class_find_device(fpga_bridge_class, NULL, dev,
+ fpga_bridge_dev_match);
+ if (!bridge_dev)
+ return ERR_PTR(-ENODEV);
+
+ return __fpga_bridge_get(bridge_dev, info);
+}
+EXPORT_SYMBOL_GPL(fpga_bridge_get);
+
/**
* fpga_bridge_put - release a reference to a bridge
*
@@ -206,7 +240,7 @@ void fpga_bridges_put(struct list_head *bridge_list)
EXPORT_SYMBOL_GPL(fpga_bridges_put);

/**
- * fpga_bridges_get_to_list - get a bridge, add it to a list
+ * of_fpga_bridge_get_to_list - get a bridge, add it to a list
*
* @np: node pointer of a FPGA bridge
* @info: fpga image specific information
@@ -216,14 +250,44 @@ EXPORT_SYMBOL_GPL(fpga_bridges_put);
*
* Return 0 for success, error code from of_fpga_bridge_get() othewise.
*/
-int fpga_bridge_get_to_list(struct device_node *np,
+int of_fpga_bridge_get_to_list(struct device_node *np,
+ struct fpga_image_info *info,
+ struct list_head *bridge_list)
+{
+ struct fpga_bridge *bridge;
+ unsigned long flags;
+
+ bridge = of_fpga_bridge_get(np, info);
+ if (IS_ERR(bridge))
+ return PTR_ERR(bridge);
+
+ spin_lock_irqsave(&bridge_list_lock, flags);
+ list_add(&bridge->node, bridge_list);
+ spin_unlock_irqrestore(&bridge_list_lock, flags);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(of_fpga_bridge_get_to_list);
+
+/**
+ * fpga_bridge_get_to_list - given device, get a bridge, add it to a list
+ *
+ * @dev: FPGA bridge device
+ * @info: fpga image specific information
+ * @bridge_list: list of FPGA bridges
+ *
+ * Get an exclusive reference to the bridge and and it to the list.
+ *
+ * Return 0 for success, error code from fpga_bridge_get() othewise.
+ */
+int fpga_bridge_get_to_list(struct device *dev,
struct fpga_image_info *info,
struct list_head *bridge_list)
{
struct fpga_bridge *bridge;
unsigned long flags;

- bridge = of_fpga_bridge_get(np, info);
+ bridge = fpga_bridge_get(dev, info);
if (IS_ERR(bridge))
return PTR_ERR(bridge);

@@ -381,7 +445,7 @@ static void __exit fpga_bridge_dev_exit(void)
}

MODULE_DESCRIPTION("FPGA Bridge Driver");
-MODULE_AUTHOR("Alan Tull <atull@xxxxxxxxxxxxxxxxxxxxx>");
+MODULE_AUTHOR("Alan Tull <atull@xxxxxxxxxx>");
MODULE_LICENSE("GPL v2");

subsys_initcall(fpga_bridge_dev_init);
diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
index d9ab7c7..91755562 100644
--- a/drivers/fpga/fpga-region.c
+++ b/drivers/fpga/fpga-region.c
@@ -183,11 +183,14 @@ static int fpga_region_get_bridges(struct fpga_region *region,
int i, ret;

/* If parent is a bridge, add to list */
- ret = fpga_bridge_get_to_list(region_np->parent, region->info,
- &region->bridge_list);
+ ret = of_fpga_bridge_get_to_list(region_np->parent, region->info,
+ &region->bridge_list);
+
+ /* -EBUSY means parent is a bridge that is under use. Give up. */
if (ret == -EBUSY)
return ret;

+ /* Zero return code means parent was a bridge and was added to list. */
if (!ret)
parent_br = region_np->parent;

@@ -207,8 +210,8 @@ static int fpga_region_get_bridges(struct fpga_region *region,
continue;

/* If node is a bridge, get it and add to list */
- ret = fpga_bridge_get_to_list(br, region->info,
- &region->bridge_list);
+ ret = of_fpga_bridge_get_to_list(br, region->info,
+ &region->bridge_list);

/* If any of the bridges are in use, give up */
if (ret == -EBUSY) {
diff --git a/include/linux/fpga/fpga-bridge.h b/include/linux/fpga/fpga-bridge.h
index dba6e3c..9f6696b 100644
--- a/include/linux/fpga/fpga-bridge.h
+++ b/include/linux/fpga/fpga-bridge.h
@@ -42,6 +42,8 @@ struct fpga_bridge {

struct fpga_bridge *of_fpga_bridge_get(struct device_node *node,
struct fpga_image_info *info);
+struct fpga_bridge *fpga_bridge_get(struct device *dev,
+ struct fpga_image_info *info);
void fpga_bridge_put(struct fpga_bridge *bridge);
int fpga_bridge_enable(struct fpga_bridge *bridge);
int fpga_bridge_disable(struct fpga_bridge *bridge);
@@ -49,9 +51,12 @@ int fpga_bridge_disable(struct fpga_bridge *bridge);
int fpga_bridges_enable(struct list_head *bridge_list);
int fpga_bridges_disable(struct list_head *bridge_list);
void fpga_bridges_put(struct list_head *bridge_list);
-int fpga_bridge_get_to_list(struct device_node *np,
+int fpga_bridge_get_to_list(struct device *dev,
struct fpga_image_info *info,
struct list_head *bridge_list);
+int of_fpga_bridge_get_to_list(struct device_node *np,
+ struct fpga_image_info *info,
+ struct list_head *bridge_list);

int fpga_bridge_register(struct device *dev, const char *name,
const struct fpga_bridge_ops *br_ops, void *priv);
--
2.7.4

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