// SPDX-License-Identifier: GPL-2.0-or-later /* * Digital Audio (PCM) abstract layer * Copyright (c) by Jaroslav Kysela <[email protected]> */ #include <linux/io.h> #include <linux/time.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/moduleparam.h> #include <linux/export.h> #include <sound/core.h> #include <sound/pcm.h> #include <sound/info.h> #include <sound/initval.h> #include "pcm_local.h" static int preallocate_dma = …; module_param(preallocate_dma, int, 0444); MODULE_PARM_DESC(…) …; static int maximum_substreams = …; module_param(maximum_substreams, int, 0444); MODULE_PARM_DESC(…) …; static const size_t snd_minimum_buffer = …; static unsigned long max_alloc_per_card = …; module_param(max_alloc_per_card, ulong, 0644); MODULE_PARM_DESC(…) …; static void __update_allocated_size(struct snd_card *card, ssize_t bytes) { … } static void update_allocated_size(struct snd_card *card, ssize_t bytes) { … } static void decrease_allocated_size(struct snd_card *card, size_t bytes) { … } static int do_alloc_pages(struct snd_card *card, int type, struct device *dev, int str, size_t size, struct snd_dma_buffer *dmab) { … } static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab) { … } /* * try to allocate as the large pages as possible. * stores the resultant memory size in *res_size. * * the minimum size is snd_minimum_buffer. it should be power of 2. */ static int preallocate_pcm_pages(struct snd_pcm_substream *substream, size_t size, bool no_fallback) { … } /** * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream. * @substream: the pcm substream instance * * Releases the pre-allocated buffer of the given substream. */ void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream) { … } /** * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm * @pcm: the pcm instance * * Releases all the pre-allocated buffers on the given pcm. */ void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm) { … } EXPORT_SYMBOL(…); #ifdef CONFIG_SND_VERBOSE_PROCFS /* * read callback for prealloc proc file * * prints the current allocated size in kB. */ static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer) { … } /* * read callback for prealloc_max proc file * * prints the maximum allowed size in kB. */ static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer) { … } /* * write callback for prealloc proc file * * accepts the preallocation size in kB. */ static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry, struct snd_info_buffer *buffer) { … } static inline void preallocate_info_init(struct snd_pcm_substream *substream) { … } #else /* !CONFIG_SND_VERBOSE_PROCFS */ static inline void preallocate_info_init(struct snd_pcm_substream *substream) { } #endif /* CONFIG_SND_VERBOSE_PROCFS */ /* * pre-allocate the buffer and create a proc file for the substream */ static int preallocate_pages(struct snd_pcm_substream *substream, int type, struct device *data, size_t size, size_t max, bool managed) { … } static int preallocate_pages_for_all(struct snd_pcm *pcm, int type, void *data, size_t size, size_t max, bool managed) { … } /** * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type * @substream: the pcm substream instance * @type: DMA type (SNDRV_DMA_TYPE_*) * @data: DMA type dependent data * @size: the requested pre-allocation size in bytes * @max: the max. allowed pre-allocation size * * Do pre-allocation for the given DMA buffer type. */ void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream, int type, struct device *data, size_t size, size_t max) { … } EXPORT_SYMBOL(…); /** * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams) * @pcm: the pcm instance * @type: DMA type (SNDRV_DMA_TYPE_*) * @data: DMA type dependent data * @size: the requested pre-allocation size in bytes * @max: the max. allowed pre-allocation size * * Do pre-allocation to all substreams of the given pcm for the * specified DMA type. */ void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm, int type, void *data, size_t size, size_t max) { … } EXPORT_SYMBOL(…); /** * snd_pcm_set_managed_buffer - set up buffer management for a substream * @substream: the pcm substream instance * @type: DMA type (SNDRV_DMA_TYPE_*) * @data: DMA type dependent data * @size: the requested pre-allocation size in bytes * @max: the max. allowed pre-allocation size * * Do pre-allocation for the given DMA buffer type, and set the managed * buffer allocation mode to the given substream. * In this mode, PCM core will allocate a buffer automatically before PCM * hw_params ops call, and release the buffer after PCM hw_free ops call * as well, so that the driver doesn't need to invoke the allocation and * the release explicitly in its callback. * When a buffer is actually allocated before the PCM hw_params call, it * turns on the runtime buffer_changed flag for drivers changing their h/w * parameters accordingly. * * When @size is non-zero and @max is zero, this tries to allocate for only * the exact buffer size without fallback, and may return -ENOMEM. * Otherwise, the function tries to allocate smaller chunks if the allocation * fails. This is the behavior of snd_pcm_set_fixed_buffer(). * * When both @size and @max are zero, the function only sets up the buffer * for later dynamic allocations. It's used typically for buffers with * SNDRV_DMA_TYPE_VMALLOC type. * * Upon successful buffer allocation and setup, the function returns 0. * * Return: zero if successful, or a negative error code */ int snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type, struct device *data, size_t size, size_t max) { … } EXPORT_SYMBOL(…); /** * snd_pcm_set_managed_buffer_all - set up buffer management for all substreams * for all substreams * @pcm: the pcm instance * @type: DMA type (SNDRV_DMA_TYPE_*) * @data: DMA type dependent data * @size: the requested pre-allocation size in bytes * @max: the max. allowed pre-allocation size * * Do pre-allocation to all substreams of the given pcm for the specified DMA * type and size, and set the managed_buffer_alloc flag to each substream. * * Return: zero if successful, or a negative error code */ int snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type, struct device *data, size_t size, size_t max) { … } EXPORT_SYMBOL(…); /** * snd_pcm_lib_malloc_pages - allocate the DMA buffer * @substream: the substream to allocate the DMA buffer to * @size: the requested buffer size in bytes * * Allocates the DMA buffer on the BUS type given earlier to * snd_pcm_lib_preallocate_xxx_pages(). * * Return: 1 if the buffer is changed, 0 if not changed, or a negative * code on failure. */ int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size) { … } EXPORT_SYMBOL(…); /** * snd_pcm_lib_free_pages - release the allocated DMA buffer. * @substream: the substream to release the DMA buffer * * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages(). * * Return: Zero if successful, or a negative error code on failure. */ int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream) { … } EXPORT_SYMBOL(…);
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