| /* |
| * Copyright (c) 2017 The Linux Foundation. All rights reserved. |
| * |
| * Previously licensed under the ISC license by Qualcomm Atheros, Inc. |
| * |
| * |
| * Permission to use, copy, modify, and/or distribute this software for |
| * any purpose with or without fee is hereby granted, provided that the |
| * above copyright notice and this permission notice appear in all |
| * copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL |
| * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED |
| * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE |
| * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL |
| * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR |
| * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER |
| * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR |
| * PERFORMANCE OF THIS SOFTWARE. |
| */ |
| |
| /* |
| * This file was originally distributed by Qualcomm Atheros, Inc. |
| * under proprietary terms before Copyright ownership was assigned |
| * to the Linux Foundation. |
| */ |
| |
| #ifndef __WLAN_HDD_REQUEST_MANAGER_H__ |
| #define __WLAN_HDD_REQUEST_MANAGER_H__ |
| |
| /** |
| * DOC: WLAN HDD REQUEST MANAGER |
| * |
| * Many operations within the wlan driver occur in an asynchronous |
| * manner. Requests are received by HDD via one of the kernel |
| * interfaces (ioctl, nl80211, virtual file system, etc.). The |
| * requests are translated to an internal format and are then passed |
| * to lower layers, usually via SME, for processing. For requests |
| * which require a response, that response comes up from the lower |
| * layers in a separate thread of execution, ultimately resulting in a |
| * call to a callback function that was provided by HDD as part of the |
| * initial request. So a mechanism is needed to synchronize the |
| * request and response. This framework provides that mechanism. |
| * |
| * Once the framework has been initialized, the typical sequence of |
| * events is as follows: |
| * |
| * Request Thread: |
| * 1. Create a &struct hdd_request_params which describes the request. |
| * 2. Call hdd_request_alloc() to allocate a &struct hdd_request. |
| * 3. Call hdd_request_priv() to get a pointer to the private data. |
| * 4. Place any information which must be shared with the Response |
| * Callback in the private data area. |
| * 5. Call hdd_request_cookie() to get the unique cookie assigned |
| * to the request. |
| * 6. Call the underlying request handling API, passing the cookie |
| * as the callback's private context. |
| * 7. Call hdd_request_wait_for_response() to wait for the response |
| * (or for the request to time out). |
| * 8. Use the return status to see if the request was successful. If |
| * it was, retrieve any response information from the private |
| * structure and prepare a response for userspace. |
| * 9. Call hdd_request_put() to relinquish access to the request. |
| * 10. Return status to the caller. |
| * |
| * Response Callback: |
| * 1. Call hdd_request_get() with the provided cookie to see if the |
| * request structure is still valid. If it returns %NULL then |
| * return since this means the request thread has already timed |
| * out. |
| * 2. Call hdd_request_priv() to get access to the private data area. |
| * 3. Write response data into the private data area. |
| * 4. Call hdd_request_complete() to indicate that the response is |
| * ready to be processed by the request thread. |
| * 5. Call hdd_request_put() to relinquish the callback function's |
| * reference to the request. |
| */ |
| |
| /* this is opaque to clients */ |
| struct hdd_request; |
| |
| /** |
| * typedef hdd_request_dealloc - Private data deallocation function |
| */ |
| typedef void (*hdd_request_dealloc)(void *priv); |
| |
| /** |
| * struct hdd_request_params - HDD request parameters |
| * @priv_size: Size of the private data area required to pass |
| * information between the request thread and the response callback. |
| * @timeout_ms: The amount of time to wait for a response in milliseconds. |
| * @dealloc: Function to be called when the request is destroyed to |
| * deallocate any allocations made in the private area of the |
| * request struct. Can be %NULL if no private allocations are |
| * made. |
| */ |
| struct hdd_request_params { |
| uint32_t priv_size; |
| uint32_t timeout_ms; |
| hdd_request_dealloc dealloc; |
| }; |
| |
| /** |
| * hdd_request_alloc() - Allocate a request struct |
| * @params: parameter block that specifies the attributes of the |
| * request |
| * |
| * This function will attempt to allocate a &struct hdd_request with |
| * the specified @params. If successful, the caller can then use |
| * request struct to make an asynchronous request. Once the request is |
| * no longer needed, the reference should be relinquished via a call |
| * to hdd_request_put(). |
| * |
| * Return: A pointer to an allocated &struct hdd_request (which also |
| * contains room for the private buffer) if the allocation is |
| * successful, %NULL if the allocation fails. |
| */ |
| struct hdd_request *hdd_request_alloc(const struct hdd_request_params *params); |
| |
| /** |
| * hdd_request_priv() - Get pointer to request private data |
| * @request: The request struct that contains the private data |
| * |
| * This function will return a pointer to the private data area that |
| * is part of the request struct. The caller must already have a valid |
| * reference to @request from either hdd_request_alloc() or |
| * hdd_request_get(). |
| * |
| * Returns: pointer to the private data area. Note that this pointer |
| * will always be an offset from the input @request pointer and hence |
| * this function will never return %NULL. |
| */ |
| void *hdd_request_priv(struct hdd_request *request); |
| |
| /** |
| * hdd_request_cookie() - Get cookie of a request |
| * @request: The request struct associated with the request |
| * |
| * This function will return the unique cookie that has been assigned |
| * to the request. This cookie can subsequently be passed to |
| * hdd_request_get() to retrieve the request. |
| * |
| * Note that the cookie is defined as a void pointer as it is intended |
| * to be passed as an opaque context pointer from HDD to underlying |
| * layers when making a request, and subsequently passed back to HDD |
| * as an opaque pointer in an asynchronous callback. |
| * |
| * Returns: The cookie assigned to the request. |
| */ |
| void *hdd_request_cookie(struct hdd_request *request); |
| |
| /** |
| * hdd_request_get() - Get a reference to a request struct |
| * @cookie: The cookie of the request struct that needs to be |
| * referenced |
| * |
| * This function will use the cookie to determine if the associated |
| * request struct is valid, and if so, will increment the reference |
| * count of the struct. This means the caller is guaranteed that the |
| * request struct is valid and the underlying private data can be |
| * dereferenced. |
| * |
| * Returns: The pointer to the request struct associated with @cookie |
| * if the request is still valid, %NULL if the underlying request |
| * struct is no longer valid. |
| */ |
| struct hdd_request *hdd_request_get(void *cookie); |
| |
| /** |
| * hdd_request_put() - Release a reference to a request struct |
| * @request: The request struct that no longer needs to be referenced |
| * |
| * This function will decrement the reference count of the struct, and |
| * will clean up the request if this is the last reference. The caller |
| * must already have a valid reference to @request, either from |
| * hdd_request_alloc() or hdd_request_get(). |
| * |
| * Returns: Nothing |
| */ |
| void hdd_request_put(struct hdd_request *request); |
| |
| /** |
| * hdd_request_wait_for_response() - Wait for a response |
| * @request: The request struct associated with the request |
| * |
| * This function will wait until either a response is received and |
| * communicated via hdd_request_complete(), or until the request |
| * timeout period expires. |
| * |
| * Returns: 0 if a response was received, -ETIMEDOUT if the response |
| * timed out. |
| */ |
| int hdd_request_wait_for_response(struct hdd_request *request); |
| |
| /** |
| * hdd_request_complete() - Complete a request |
| * @request: The request struct associated with the request |
| * |
| * This function is used to indicate that a response has been received |
| * and that any information required by the request thread has been |
| * copied into the private data area of the request struct. This will |
| * unblock any hdd_request_wait_for_response() that is pending on this |
| * @request. |
| * |
| * Returns: Nothing |
| */ |
| void hdd_request_complete(struct hdd_request *request); |
| |
| /** |
| * hdd_request_manager_init() - Initialize the HDD Request Manager |
| * |
| * This function must be called during system initialization to |
| * initialize the HDD Request Manager. |
| * |
| * Returns: Nothing |
| */ |
| void hdd_request_manager_init(void); |
| |
| /** |
| * hdd_request_manager_deinit() - Deinitialize the HDD Request Manager |
| * |
| * This function must be called during system shutdown to deinitialize |
| * the HDD Request Manager. |
| * |
| * Returns: Nothing |
| */ |
| void hdd_request_manager_deinit(void); |
| |
| #endif /* __WLAN_HDD_REQUEST_MANAGER_H__ */ |