| /* |
| * |
| * (C) COPYRIGHT 2008-2013 ARM Limited. All rights reserved. |
| * |
| * This program is free software and is provided to you under the terms of the |
| * GNU General Public License version 2 as published by the Free Software |
| * Foundation, and any use by you of this program is subject to the terms |
| * of such GNU licence. |
| * |
| * A copy of the licence is included with the program, and can also be obtained |
| * from Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
| * Boston, MA 02110-1301, USA. |
| * |
| */ |
| |
| |
| |
| |
| |
| /** |
| * @file ump_kernel_descriptor_mapping.h |
| */ |
| |
| #ifndef _UMP_KERNEL_DESCRIPTOR_MAPPING_H_ |
| #define _UMP_KERNEL_DESCRIPTOR_MAPPING_H_ |
| |
| #include <linux/rwsem.h> |
| #include <linux/slab.h> |
| /** |
| * The actual descriptor mapping table, never directly accessed by clients |
| */ |
| typedef struct umpp_descriptor_table |
| { |
| /* keep as a unsigned long to rely on the OS's bitops support */ |
| unsigned long * usage; /**< Pointer to bitpattern indicating if a descriptor is valid/used(1) or not(0) */ |
| void** mappings; /**< Array of the pointers the descriptors map to */ |
| } umpp_descriptor_table; |
| |
| /** |
| * The descriptor mapping object |
| * Provides a separate namespace where we can map an integer to a pointer |
| */ |
| typedef struct umpp_descriptor_mapping |
| { |
| struct rw_semaphore lock; /**< Lock protecting access to the mapping object */ |
| unsigned int max_nr_mappings_allowed; /**< Max number of mappings to support in this namespace */ |
| unsigned int current_nr_mappings; /**< Current number of possible mappings */ |
| umpp_descriptor_table * table; /**< Pointer to the current mapping table */ |
| } umpp_descriptor_mapping; |
| |
| /** |
| * Create a descriptor mapping object. |
| * Create a descriptor mapping capable of holding init_entries growable to max_entries. |
| * ID 0 is reserved so the number of available entries will be max - 1. |
| * @param init_entries Number of entries to preallocate memory for |
| * @param max_entries Number of entries to max support |
| * @return Pointer to a descriptor mapping object, NULL on failure |
| */ |
| umpp_descriptor_mapping * umpp_descriptor_mapping_create(unsigned int init_entries, unsigned int max_entries); |
| |
| /** |
| * Destroy a descriptor mapping object |
| * @param[in] map The map to free |
| */ |
| void umpp_descriptor_mapping_destroy(umpp_descriptor_mapping * map); |
| |
| /** |
| * Allocate a new mapping entry (descriptor ID) |
| * Allocates a new entry in the map. |
| * @param[in] map The map to allocate a new entry in |
| * @param[in] target The value to map to |
| * @return The descriptor allocated, ID 0 on failure. |
| */ |
| unsigned int umpp_descriptor_mapping_allocate(umpp_descriptor_mapping * map, void * target); |
| |
| /** |
| * Get the value mapped to by a descriptor ID |
| * @param[in] map The map to lookup the descriptor id in |
| * @param[in] descriptor The descriptor ID to lookup |
| * @param[out] target Pointer to a pointer which will receive the stored value |
| * |
| * @return 0 on success lookup, -EINVAL on lookup failure. |
| */ |
| int umpp_descriptor_mapping_lookup(umpp_descriptor_mapping * map, unsigned int descriptor, void** const target); |
| |
| /** |
| * Free the descriptor ID |
| * For the descriptor to be reused it has to be freed |
| * @param[in] map The map to free the descriptor from |
| * @param descriptor The descriptor ID to free |
| */ |
| void umpp_descriptor_mapping_remove(umpp_descriptor_mapping * map, unsigned int descriptor); |
| |
| #endif /* _UMP_KERNEL_DESCRIPTOR_MAPPING_H_ */ |
