forked from mirrors/linux
1da11f8220
The current implementation of the fpga bridge assumes that the low-level
module registers a driver for the parent device and uses its owner pointer
to take the module's refcount. This approach is problematic since it can
lead to a null pointer dereference while attempting to get the bridge if
the parent device does not have a driver.
To address this problem, add a module owner pointer to the fpga_bridge
struct and use it to take the module's refcount. Modify the function for
registering a bridge to take an additional owner module parameter and
rename it to avoid conflicts. Use the old function name for a helper macro
that automatically sets the module that registers the bridge as the owner.
This ensures compatibility with existing low-level control modules and
reduces the chances of registering a bridge without setting the owner.
Also, update the documentation to keep it consistent with the new interface
for registering an fpga bridge.
Other changes: opportunistically move put_device() from __fpga_bridge_get()
to fpga_bridge_get() and of_fpga_bridge_get() to improve code clarity since
the bridge device is taken in these functions.
Fixes: 21aeda950c ("fpga: add fpga bridge framework")
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Xu Yilun <yilun.xu@intel.com>
Reviewed-by: Russ Weight <russ.weight@linux.dev>
Signed-off-by: Marco Pagani <marpagan@redhat.com>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20240322171839.233864-1-marpagan@redhat.com
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
92 lines
3.1 KiB
C
92 lines
3.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_FPGA_BRIDGE_H
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#define _LINUX_FPGA_BRIDGE_H
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#include <linux/device.h>
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#include <linux/fpga/fpga-mgr.h>
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struct fpga_bridge;
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/**
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* struct fpga_bridge_ops - ops for low level FPGA bridge drivers
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* @enable_show: returns the FPGA bridge's status
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* @enable_set: set an FPGA bridge as enabled or disabled
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* @fpga_bridge_remove: set FPGA into a specific state during driver remove
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* @groups: optional attribute groups.
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*/
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struct fpga_bridge_ops {
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int (*enable_show)(struct fpga_bridge *bridge);
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int (*enable_set)(struct fpga_bridge *bridge, bool enable);
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void (*fpga_bridge_remove)(struct fpga_bridge *bridge);
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const struct attribute_group **groups;
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};
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/**
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* struct fpga_bridge_info - collection of parameters an FPGA Bridge
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* @name: fpga bridge name
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* @br_ops: pointer to structure of fpga bridge ops
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* @priv: fpga bridge private data
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*
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* fpga_bridge_info contains parameters for the register function. These
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* are separated into an info structure because they some are optional
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* others could be added to in the future. The info structure facilitates
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* maintaining a stable API.
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*/
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struct fpga_bridge_info {
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const char *name;
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const struct fpga_bridge_ops *br_ops;
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void *priv;
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};
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/**
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* struct fpga_bridge - FPGA bridge structure
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* @name: name of low level FPGA bridge
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* @dev: FPGA bridge device
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* @mutex: enforces exclusive reference to bridge
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* @br_ops: pointer to struct of FPGA bridge ops
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* @br_ops_owner: module containing the br_ops
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* @info: fpga image specific information
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* @node: FPGA bridge list node
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* @priv: low level driver private date
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*/
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struct fpga_bridge {
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const char *name;
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struct device dev;
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struct mutex mutex; /* for exclusive reference to bridge */
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const struct fpga_bridge_ops *br_ops;
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struct module *br_ops_owner;
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struct fpga_image_info *info;
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struct list_head node;
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void *priv;
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};
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#define to_fpga_bridge(d) container_of(d, struct fpga_bridge, dev)
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struct fpga_bridge *of_fpga_bridge_get(struct device_node *node,
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struct fpga_image_info *info);
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struct fpga_bridge *fpga_bridge_get(struct device *dev,
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struct fpga_image_info *info);
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void fpga_bridge_put(struct fpga_bridge *bridge);
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int fpga_bridge_enable(struct fpga_bridge *bridge);
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int fpga_bridge_disable(struct fpga_bridge *bridge);
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int fpga_bridges_enable(struct list_head *bridge_list);
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int fpga_bridges_disable(struct list_head *bridge_list);
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void fpga_bridges_put(struct list_head *bridge_list);
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int fpga_bridge_get_to_list(struct device *dev,
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struct fpga_image_info *info,
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struct list_head *bridge_list);
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int of_fpga_bridge_get_to_list(struct device_node *np,
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struct fpga_image_info *info,
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struct list_head *bridge_list);
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#define fpga_bridge_register(parent, name, br_ops, priv) \
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__fpga_bridge_register(parent, name, br_ops, priv, THIS_MODULE)
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struct fpga_bridge *
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__fpga_bridge_register(struct device *parent, const char *name,
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const struct fpga_bridge_ops *br_ops, void *priv,
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struct module *owner);
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void fpga_bridge_unregister(struct fpga_bridge *br);
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#endif /* _LINUX_FPGA_BRIDGE_H */
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