diff options
Diffstat (limited to 'sound/mips')
| -rw-r--r-- | sound/mips/Kconfig | 7 | ||||
| -rw-r--r-- | sound/mips/Makefile | 1 | ||||
| -rw-r--r-- | sound/mips/snd-n64.c | 372 |
3 files changed, 380 insertions, 0 deletions
diff --git a/sound/mips/Kconfig b/sound/mips/Kconfig index b497b803c834..c484b1e42395 100644 --- a/sound/mips/Kconfig +++ b/sound/mips/Kconfig @@ -24,5 +24,12 @@ config SND_SGI_HAL2 help Sound support for the SGI Indy and Indigo2 Workstation. +config SND_N64 + bool "N64 Audio" + depends on MACH_NINTENDO64 && SND=y + select SND_PCM + help + Sound support for the N64. + endif # SND_MIPS diff --git a/sound/mips/Makefile b/sound/mips/Makefile index ccc364eca692..7c86268b2bf3 100644 --- a/sound/mips/Makefile +++ b/sound/mips/Makefile @@ -9,3 +9,4 @@ snd-sgi-hal2-objs := hal2.o # Toplevel Module Dependency obj-$(CONFIG_SND_SGI_O2) += snd-sgi-o2.o obj-$(CONFIG_SND_SGI_HAL2) += snd-sgi-hal2.o +obj-$(CONFIG_SND_N64) += snd-n64.o diff --git a/sound/mips/snd-n64.c b/sound/mips/snd-n64.c new file mode 100644 index 000000000000..ca6b4b99da98 --- /dev/null +++ b/sound/mips/snd-n64.c @@ -0,0 +1,372 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Sound driver for Nintendo 64. + * + * Copyright 2021 Lauri Kasanen + */ + +#include <linux/dma-mapping.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/log2.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/spinlock.h> + +#include <sound/control.h> +#include <sound/core.h> +#include <sound/initval.h> +#include <sound/pcm.h> +#include <sound/pcm_params.h> + +MODULE_AUTHOR("Lauri Kasanen <cand@gmx.com>"); +MODULE_DESCRIPTION("N64 Audio"); +MODULE_LICENSE("GPL"); + +#define AI_NTSC_DACRATE 48681812 +#define AI_STATUS_BUSY (1 << 30) +#define AI_STATUS_FULL (1 << 31) + +#define AI_ADDR_REG 0 +#define AI_LEN_REG 1 +#define AI_CONTROL_REG 2 +#define AI_STATUS_REG 3 +#define AI_RATE_REG 4 +#define AI_BITCLOCK_REG 5 + +#define MI_INTR_REG 2 +#define MI_MASK_REG 3 + +#define MI_INTR_AI 0x04 + +#define MI_MASK_CLR_AI 0x0010 +#define MI_MASK_SET_AI 0x0020 + + +struct n64audio { + u32 __iomem *ai_reg_base; + u32 __iomem *mi_reg_base; + + void *ring_base; + dma_addr_t ring_base_dma; + + struct snd_card *card; + + struct { + struct snd_pcm_substream *substream; + int pos, nextpos; + u32 writesize; + u32 bufsize; + spinlock_t lock; + } chan; +}; + +static void n64audio_write_reg(struct n64audio *priv, const u8 reg, const u32 value) +{ + writel(value, priv->ai_reg_base + reg); +} + +static void n64mi_write_reg(struct n64audio *priv, const u8 reg, const u32 value) +{ + writel(value, priv->mi_reg_base + reg); +} + +static u32 n64mi_read_reg(struct n64audio *priv, const u8 reg) +{ + return readl(priv->mi_reg_base + reg); +} + +static void n64audio_push(struct n64audio *priv) +{ + struct snd_pcm_runtime *runtime = priv->chan.substream->runtime; + unsigned long flags; + u32 count; + + spin_lock_irqsave(&priv->chan.lock, flags); + + count = priv->chan.writesize; + + memcpy(priv->ring_base + priv->chan.nextpos, + runtime->dma_area + priv->chan.nextpos, count); + + /* + * The hw registers are double-buffered, and the IRQ fires essentially + * one period behind. The core only allows one period's distance, so we + * keep a private DMA buffer to afford two. + */ + n64audio_write_reg(priv, AI_ADDR_REG, priv->ring_base_dma + priv->chan.nextpos); + barrier(); + n64audio_write_reg(priv, AI_LEN_REG, count); + + priv->chan.nextpos += count; + priv->chan.nextpos %= priv->chan.bufsize; + + runtime->delay = runtime->period_size; + + spin_unlock_irqrestore(&priv->chan.lock, flags); +} + +static irqreturn_t n64audio_isr(int irq, void *dev_id) +{ + struct n64audio *priv = dev_id; + const u32 intrs = n64mi_read_reg(priv, MI_INTR_REG); + unsigned long flags; + + // Check it's ours + if (!(intrs & MI_INTR_AI)) + return IRQ_NONE; + + n64audio_write_reg(priv, AI_STATUS_REG, 1); + + if (priv->chan.substream && snd_pcm_running(priv->chan.substream)) { + spin_lock_irqsave(&priv->chan.lock, flags); + + priv->chan.pos = priv->chan.nextpos; + + spin_unlock_irqrestore(&priv->chan.lock, flags); + + snd_pcm_period_elapsed(priv->chan.substream); + if (priv->chan.substream && snd_pcm_running(priv->chan.substream)) + n64audio_push(priv); + } + + return IRQ_HANDLED; +} + +static const struct snd_pcm_hardware n64audio_pcm_hw = { + .info = (SNDRV_PCM_INFO_MMAP | + SNDRV_PCM_INFO_MMAP_VALID | + SNDRV_PCM_INFO_INTERLEAVED | + SNDRV_PCM_INFO_BLOCK_TRANSFER), + .formats = SNDRV_PCM_FMTBIT_S16_BE, + .rates = SNDRV_PCM_RATE_8000_48000, + .rate_min = 8000, + .rate_max = 48000, + .channels_min = 2, + .channels_max = 2, + .buffer_bytes_max = 32768, + .period_bytes_min = 1024, + .period_bytes_max = 32768, + .periods_min = 3, + // 3 periods lets the double-buffering hw read one buffer behind safely + .periods_max = 128, +}; + +static int hw_rule_period_size(struct snd_pcm_hw_params *params, + struct snd_pcm_hw_rule *rule) +{ + struct snd_interval *c = hw_param_interval(params, + SNDRV_PCM_HW_PARAM_PERIOD_SIZE); + int changed = 0; + + /* + * The DMA unit has errata on (start + len) & 0x3fff == 0x2000. + * This constraint makes sure that the period size is not a power of two, + * which combined with dma_alloc_coherent aligning the buffer to the largest + * PoT <= size guarantees it won't be hit. + */ + + if (is_power_of_2(c->min)) { + c->min += 2; + changed = 1; + } + if (is_power_of_2(c->max)) { + c->max -= 2; + changed = 1; + } + if (snd_interval_checkempty(c)) { + c->empty = 1; + return -EINVAL; + } + + return changed; +} + +static int n64audio_pcm_open(struct snd_pcm_substream *substream) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + int err; + + runtime->hw = n64audio_pcm_hw; + err = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); + if (err < 0) + return err; + + err = snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 2); + if (err < 0) + return err; + + err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, + hw_rule_period_size, NULL, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1); + if (err < 0) + return err; + + return 0; +} + +static int n64audio_pcm_prepare(struct snd_pcm_substream *substream) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + struct n64audio *priv = substream->pcm->private_data; + u32 rate; + + rate = ((2 * AI_NTSC_DACRATE / runtime->rate) + 1) / 2 - 1; + + n64audio_write_reg(priv, AI_RATE_REG, rate); + + rate /= 66; + if (rate > 16) + rate = 16; + n64audio_write_reg(priv, AI_BITCLOCK_REG, rate - 1); + + spin_lock_irq(&priv->chan.lock); + + /* Setup the pseudo-dma transfer pointers. */ + priv->chan.pos = 0; + priv->chan.nextpos = 0; + priv->chan.substream = substream; + priv->chan.writesize = snd_pcm_lib_period_bytes(substream); + priv->chan.bufsize = snd_pcm_lib_buffer_bytes(substream); + + spin_unlock_irq(&priv->chan.lock); + return 0; +} + +static int n64audio_pcm_trigger(struct snd_pcm_substream *substream, + int cmd) +{ + struct n64audio *priv = substream->pcm->private_data; + + switch (cmd) { + case SNDRV_PCM_TRIGGER_START: + n64audio_push(substream->pcm->private_data); + n64audio_write_reg(priv, AI_CONTROL_REG, 1); + n64mi_write_reg(priv, MI_MASK_REG, MI_MASK_SET_AI); + break; + case SNDRV_PCM_TRIGGER_STOP: + n64audio_write_reg(priv, AI_CONTROL_REG, 0); + n64mi_write_reg(priv, MI_MASK_REG, MI_MASK_CLR_AI); + break; + default: + return -EINVAL; + } + return 0; +} + +static snd_pcm_uframes_t n64audio_pcm_pointer(struct snd_pcm_substream *substream) +{ + struct n64audio *priv = substream->pcm->private_data; + + return bytes_to_frames(substream->runtime, + priv->chan.pos); +} + +static int n64audio_pcm_close(struct snd_pcm_substream *substream) +{ + struct n64audio *priv = substream->pcm->private_data; + + priv->chan.substream = NULL; + + return 0; +} + +static const struct snd_pcm_ops n64audio_pcm_ops = { + .open = n64audio_pcm_open, + .prepare = n64audio_pcm_prepare, + .trigger = n64audio_pcm_trigger, + .pointer = n64audio_pcm_pointer, + .close = n64audio_pcm_close, +}; + +/* + * The target device is embedded and RAM-constrained. We save RAM + * by initializing in __init code that gets dropped late in boot. + * For the same reason there is no module or unloading support. + */ +static int __init n64audio_probe(struct platform_device *pdev) +{ + struct snd_card *card; + struct snd_pcm *pcm; + struct n64audio *priv; + struct resource *res; + int err; + + err = snd_card_new(&pdev->dev, SNDRV_DEFAULT_IDX1, + SNDRV_DEFAULT_STR1, + THIS_MODULE, sizeof(*priv), &card); + if (err < 0) + return err; + + priv = card->private_data; + + spin_lock_init(&priv->chan.lock); + + priv->card = card; + + priv->ring_base = dma_alloc_coherent(card->dev, 32 * 1024, &priv->ring_base_dma, + GFP_DMA|GFP_KERNEL); + if (!priv->ring_base) { + err = -ENOMEM; + goto fail_card; + } + + priv->mi_reg_base = devm_platform_ioremap_resource(pdev, 0); + if (!priv->mi_reg_base) { + err = -EINVAL; + goto fail_dma_alloc; + } + + priv->ai_reg_base = devm_platform_ioremap_resource(pdev, 1); + if (!priv->ai_reg_base) { + err = -EINVAL; + goto fail_dma_alloc; + } + + err = snd_pcm_new(card, "N64 Audio", 0, 1, 0, &pcm); + if (err < 0) + goto fail_dma_alloc; + + pcm->private_data = priv; + strcpy(pcm->name, "N64 Audio"); + + snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &n64audio_pcm_ops); + snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, card->dev, 0, 0); + + strcpy(card->driver, "N64 Audio"); + strcpy(card->shortname, "N64 Audio"); + strcpy(card->longname, "N64 Audio"); + + res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); + if (devm_request_irq(&pdev->dev, res->start, n64audio_isr, + IRQF_SHARED, "N64 Audio", priv)) { + err = -EBUSY; + goto fail_dma_alloc; + } + + err = snd_card_register(card); + if (err < 0) + goto fail_dma_alloc; + + return 0; + +fail_dma_alloc: + dma_free_coherent(card->dev, 32 * 1024, priv->ring_base, priv->ring_base_dma); + +fail_card: + snd_card_free(card); + return err; +} + +static struct platform_driver n64audio_driver = { + .driver = { + .name = "n64audio", + }, +}; + +static int __init n64audio_init(void) +{ + return platform_driver_probe(&n64audio_driver, n64audio_probe); +} + +module_init(n64audio_init); |