// SPDX-License-Identifier: GPL-2.0-or-later /* * Digital Audio (PCM) abstract layer * Copyright (c) by Jaroslav Kysela */ #include #include #include #include #include #include #include #include #include #include #include "pcm_local.h" static int preallocate_dma = 1; module_param(preallocate_dma, int, 0444); MODULE_PARM_DESC(preallocate_dma, "Preallocate DMA memory when the PCM devices are initialized."); static int maximum_substreams = 4; module_param(maximum_substreams, int, 0444); MODULE_PARM_DESC(maximum_substreams, "Maximum substreams with preallocated DMA memory."); static const size_t snd_minimum_buffer = 16384; static unsigned long max_alloc_per_card = 32UL * 1024UL * 1024UL; module_param(max_alloc_per_card, ulong, 0644); MODULE_PARM_DESC(max_alloc_per_card, "Max total allocation bytes per card."); static void __update_allocated_size(struct snd_card *card, ssize_t bytes) { card->total_pcm_alloc_bytes += bytes; } static void update_allocated_size(struct snd_card *card, ssize_t bytes) { guard(mutex)(&card->memory_mutex); __update_allocated_size(card, bytes); } static void decrease_allocated_size(struct snd_card *card, size_t bytes) { guard(mutex)(&card->memory_mutex); WARN_ON(card->total_pcm_alloc_bytes < bytes); __update_allocated_size(card, -(ssize_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) { enum dma_data_direction dir; int err; /* check and reserve the requested size */ scoped_guard(mutex, &card->memory_mutex) { if (max_alloc_per_card && card->total_pcm_alloc_bytes + size > max_alloc_per_card) return -ENOMEM; __update_allocated_size(card, size); } if (str == SNDRV_PCM_STREAM_PLAYBACK) dir = DMA_TO_DEVICE; else dir = DMA_FROM_DEVICE; err = snd_dma_alloc_dir_pages(type, dev, dir, size, dmab); if (!err) { /* the actual allocation size might be bigger than requested, * and we need to correct the account */ if (dmab->bytes != size) update_allocated_size(card, dmab->bytes - size); } else { /* take back on allocation failure */ decrease_allocated_size(card, size); } return err; } static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab) { if (!dmab->area) return; decrease_allocated_size(card, dmab->bytes); snd_dma_free_pages(dmab); dmab->area = NULL; } /* * 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) { struct snd_dma_buffer *dmab = &substream->dma_buffer; struct snd_card *card = substream->pcm->card; size_t orig_size = size; int err; do { err = do_alloc_pages(card, dmab->dev.type, dmab->dev.dev, substream->stream, size, dmab); if (err != -ENOMEM) return err; if (no_fallback) break; size >>= 1; } while (size >= snd_minimum_buffer); dmab->bytes = 0; /* tell error */ pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n", substream->pcm->card->number, substream->pcm->device, substream->stream ? 'c' : 'p', substream->number, substream->pcm->name, orig_size); return -ENOMEM; } /** * 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) { do_free_pages(substream->pcm->card, &substream->dma_buffer); } /** * 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) { struct snd_pcm_substream *substream; int stream; for_each_pcm_substream(pcm, stream, substream) snd_pcm_lib_preallocate_free(substream); } EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all); #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) { struct snd_pcm_substream *substream = entry->private_data; snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024); } /* * 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) { struct snd_pcm_substream *substream = entry->private_data; snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024); } /* * 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) { struct snd_pcm_substream *substream = entry->private_data; struct snd_card *card = substream->pcm->card; char line[64], str[64]; unsigned long size; struct snd_dma_buffer new_dmab; guard(mutex)(&substream->pcm->open_mutex); if (substream->runtime) { buffer->error = -EBUSY; return; } if (!snd_info_get_line(buffer, line, sizeof(line))) { snd_info_get_str(str, line, sizeof(str)); buffer->error = kstrtoul(str, 10, &size); if (buffer->error != 0) return; size *= 1024; if ((size != 0 && size < 8192) || size > substream->dma_max) { buffer->error = -EINVAL; return; } if (substream->dma_buffer.bytes == size) return; memset(&new_dmab, 0, sizeof(new_dmab)); new_dmab.dev = substream->dma_buffer.dev; if (size > 0) { if (do_alloc_pages(card, substream->dma_buffer.dev.type, substream->dma_buffer.dev.dev, substream->stream, size, &new_dmab) < 0) { buffer->error = -ENOMEM; pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %lu\n", substream->pcm->card->number, substream->pcm->device, substream->stream ? 'c' : 'p', substream->number, substream->pcm->name, size); return; } substream->buffer_bytes_max = size; } else { substream->buffer_bytes_max = UINT_MAX; } if (substream->dma_buffer.area) do_free_pages(card, &substream->dma_buffer); substream->dma_buffer = new_dmab; } else { buffer->error = -EINVAL; } } static inline void preallocate_info_init(struct snd_pcm_substream *substream) { struct snd_info_entry *entry; entry = snd_info_create_card_entry(substream->pcm->card, "prealloc", substream->proc_root); if (entry) { snd_info_set_text_ops(entry, substream, snd_pcm_lib_preallocate_proc_read); entry->c.text.write = snd_pcm_lib_preallocate_proc_write; entry->mode |= 0200; } entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max", substream->proc_root); if (entry) snd_info_set_text_ops(entry, substream, snd_pcm_lib_preallocate_max_proc_read); } #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) { int err; if (snd_BUG_ON(substream->dma_buffer.dev.type)) return -EINVAL; substream->dma_buffer.dev.type = type; substream->dma_buffer.dev.dev = data; if (size > 0) { if (!max) { /* no fallback, only also inform -ENOMEM */ err = preallocate_pcm_pages(substream, size, true); if (err < 0) return err; } else if (preallocate_dma && substream->number < maximum_substreams) { err = preallocate_pcm_pages(substream, size, false); if (err < 0 && err != -ENOMEM) return err; } } if (substream->dma_buffer.bytes > 0) substream->buffer_bytes_max = substream->dma_buffer.bytes; substream->dma_max = max; if (max > 0) preallocate_info_init(substream); if (managed) substream->managed_buffer_alloc = 1; return 0; } static int preallocate_pages_for_all(struct snd_pcm *pcm, int type, void *data, size_t size, size_t max, bool managed) { struct snd_pcm_substream *substream; int stream, err; for_each_pcm_substream(pcm, stream, substream) { err = preallocate_pages(substream, type, data, size, max, managed); if (err < 0) return err; } return 0; } /** * 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) { preallocate_pages(substream, type, data, size, max, false); } EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages); /** * 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) { preallocate_pages_for_all(pcm, type, data, size, max, false); } EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all); /** * 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) { return preallocate_pages(substream, type, data, size, max, true); } EXPORT_SYMBOL(snd_pcm_set_managed_buffer); /** * 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) { return preallocate_pages_for_all(pcm, type, data, size, max, true); } EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all); /** * 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) { struct snd_card *card; struct snd_pcm_runtime *runtime; struct snd_dma_buffer *dmab = NULL; if (PCM_RUNTIME_CHECK(substream)) return -EINVAL; if (snd_BUG_ON(substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_UNKNOWN)) return -EINVAL; runtime = substream->runtime; card = substream->pcm->card; if (runtime->dma_buffer_p) { /* perphaps, we might free the large DMA memory region to save some space here, but the actual solution costs us less time */ if (runtime->dma_buffer_p->bytes >= size) { runtime->dma_bytes = size; return 0; /* ok, do not change */ } snd_pcm_lib_free_pages(substream); } if (substream->dma_buffer.area != NULL && substream->dma_buffer.bytes >= size) { dmab = &substream->dma_buffer; /* use the pre-allocated buffer */ } else { /* dma_max=0 means the fixed size preallocation */ if (substream->dma_buffer.area && !substream->dma_max) return -ENOMEM; dmab = kzalloc(sizeof(*dmab), GFP_KERNEL); if (! dmab) return -ENOMEM; dmab->dev = substream->dma_buffer.dev; if (do_alloc_pages(card, substream->dma_buffer.dev.type, substream->dma_buffer.dev.dev, substream->stream, size, dmab) < 0) { kfree(dmab); pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n", substream->pcm->card->number, substream->pcm->device, substream->stream ? 'c' : 'p', substream->number, substream->pcm->name, size); return -ENOMEM; } } snd_pcm_set_runtime_buffer(substream, dmab); runtime->dma_bytes = size; return 1; /* area was changed */ } EXPORT_SYMBOL(snd_pcm_lib_malloc_pages); /** * 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) { struct snd_pcm_runtime *runtime; if (PCM_RUNTIME_CHECK(substream)) return -EINVAL; runtime = substream->runtime; if (runtime->dma_area == NULL) return 0; if (runtime->dma_buffer_p != &substream->dma_buffer) { struct snd_card *card = substream->pcm->card; /* it's a newly allocated buffer. release it now. */ do_free_pages(card, runtime->dma_buffer_p); kfree(runtime->dma_buffer_p); } snd_pcm_set_runtime_buffer(substream, NULL); return 0; } EXPORT_SYMBOL(snd_pcm_lib_free_pages);