sound: Add n64 driver
This adds support for the Nintendo 64 console's sound. Signed-off-by: Lauri Kasanen <cand@gmx.com> Reviewed-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This commit is contained in:
Lauri Kasanen
Thomas Bogendoerfer
Родитель
42b20995fa
Коммит
1448f8acf4
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@ -24,5 +24,12 @@ config SND_SGI_HAL2
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help
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Sound support for the SGI Indy and Indigo2 Workstation.
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config SND_N64
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bool "N64 Audio"
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depends on MACH_NINTENDO64 && SND=y
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select SND_PCM
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help
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Sound support for the N64.
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endif # SND_MIPS
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@ -9,3 +9,4 @@ snd-sgi-hal2-objs := hal2.o
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# Toplevel Module Dependency
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obj-$(CONFIG_SND_SGI_O2) += snd-sgi-o2.o
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obj-$(CONFIG_SND_SGI_HAL2) += snd-sgi-hal2.o
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obj-$(CONFIG_SND_N64) += snd-n64.o
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@ -0,0 +1,372 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Sound driver for Nintendo 64.
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*
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* Copyright 2021 Lauri Kasanen
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*/
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#include <linux/dma-mapping.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/log2.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/spinlock.h>
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#include <sound/control.h>
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#include <sound/core.h>
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#include <sound/initval.h>
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#include <sound/pcm.h>
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#include <sound/pcm_params.h>
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MODULE_AUTHOR("Lauri Kasanen <cand@gmx.com>");
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MODULE_DESCRIPTION("N64 Audio");
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MODULE_LICENSE("GPL");
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#define AI_NTSC_DACRATE 48681812
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#define AI_STATUS_BUSY (1 << 30)
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#define AI_STATUS_FULL (1 << 31)
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#define AI_ADDR_REG 0
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#define AI_LEN_REG 1
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#define AI_CONTROL_REG 2
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#define AI_STATUS_REG 3
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#define AI_RATE_REG 4
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#define AI_BITCLOCK_REG 5
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#define MI_INTR_REG 2
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#define MI_MASK_REG 3
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#define MI_INTR_AI 0x04
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#define MI_MASK_CLR_AI 0x0010
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#define MI_MASK_SET_AI 0x0020
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struct n64audio {
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u32 __iomem *ai_reg_base;
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u32 __iomem *mi_reg_base;
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void *ring_base;
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dma_addr_t ring_base_dma;
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struct snd_card *card;
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struct {
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struct snd_pcm_substream *substream;
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int pos, nextpos;
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u32 writesize;
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u32 bufsize;
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spinlock_t lock;
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} chan;
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};
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static void n64audio_write_reg(struct n64audio *priv, const u8 reg, const u32 value)
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{
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writel(value, priv->ai_reg_base + reg);
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}
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static void n64mi_write_reg(struct n64audio *priv, const u8 reg, const u32 value)
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{
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writel(value, priv->mi_reg_base + reg);
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}
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static u32 n64mi_read_reg(struct n64audio *priv, const u8 reg)
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{
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return readl(priv->mi_reg_base + reg);
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}
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static void n64audio_push(struct n64audio *priv)
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{
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struct snd_pcm_runtime *runtime = priv->chan.substream->runtime;
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unsigned long flags;
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u32 count;
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spin_lock_irqsave(&priv->chan.lock, flags);
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count = priv->chan.writesize;
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memcpy(priv->ring_base + priv->chan.nextpos,
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runtime->dma_area + priv->chan.nextpos, count);
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/*
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* The hw registers are double-buffered, and the IRQ fires essentially
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* one period behind. The core only allows one period's distance, so we
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* keep a private DMA buffer to afford two.
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*/
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n64audio_write_reg(priv, AI_ADDR_REG, priv->ring_base_dma + priv->chan.nextpos);
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barrier();
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n64audio_write_reg(priv, AI_LEN_REG, count);
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priv->chan.nextpos += count;
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priv->chan.nextpos %= priv->chan.bufsize;
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runtime->delay = runtime->period_size;
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spin_unlock_irqrestore(&priv->chan.lock, flags);
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}
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static irqreturn_t n64audio_isr(int irq, void *dev_id)
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{
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struct n64audio *priv = dev_id;
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const u32 intrs = n64mi_read_reg(priv, MI_INTR_REG);
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unsigned long flags;
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// Check it's ours
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if (!(intrs & MI_INTR_AI))
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return IRQ_NONE;
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n64audio_write_reg(priv, AI_STATUS_REG, 1);
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if (priv->chan.substream && snd_pcm_running(priv->chan.substream)) {
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spin_lock_irqsave(&priv->chan.lock, flags);
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priv->chan.pos = priv->chan.nextpos;
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spin_unlock_irqrestore(&priv->chan.lock, flags);
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snd_pcm_period_elapsed(priv->chan.substream);
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if (priv->chan.substream && snd_pcm_running(priv->chan.substream))
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n64audio_push(priv);
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}
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return IRQ_HANDLED;
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}
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static const struct snd_pcm_hardware n64audio_pcm_hw = {
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.info = (SNDRV_PCM_INFO_MMAP |
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SNDRV_PCM_INFO_MMAP_VALID |
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SNDRV_PCM_INFO_INTERLEAVED |
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SNDRV_PCM_INFO_BLOCK_TRANSFER),
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.formats = SNDRV_PCM_FMTBIT_S16_BE,
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.rates = SNDRV_PCM_RATE_8000_48000,
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.rate_min = 8000,
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.rate_max = 48000,
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.channels_min = 2,
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.channels_max = 2,
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.buffer_bytes_max = 32768,
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.period_bytes_min = 1024,
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.period_bytes_max = 32768,
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.periods_min = 3,
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// 3 periods lets the double-buffering hw read one buffer behind safely
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.periods_max = 128,
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};
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static int hw_rule_period_size(struct snd_pcm_hw_params *params,
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struct snd_pcm_hw_rule *rule)
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{
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struct snd_interval *c = hw_param_interval(params,
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SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
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int changed = 0;
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/*
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* The DMA unit has errata on (start + len) & 0x3fff == 0x2000.
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* This constraint makes sure that the period size is not a power of two,
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* which combined with dma_alloc_coherent aligning the buffer to the largest
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* PoT <= size guarantees it won't be hit.
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*/
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if (is_power_of_2(c->min)) {
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c->min += 2;
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changed = 1;
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}
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if (is_power_of_2(c->max)) {
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c->max -= 2;
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changed = 1;
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}
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if (snd_interval_checkempty(c)) {
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c->empty = 1;
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return -EINVAL;
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}
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return changed;
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}
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static int n64audio_pcm_open(struct snd_pcm_substream *substream)
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{
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struct snd_pcm_runtime *runtime = substream->runtime;
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int err;
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runtime->hw = n64audio_pcm_hw;
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err = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
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if (err < 0)
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return err;
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err = snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 2);
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if (err < 0)
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return err;
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err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
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hw_rule_period_size, NULL, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
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if (err < 0)
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return err;
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return 0;
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}
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static int n64audio_pcm_prepare(struct snd_pcm_substream *substream)
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{
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struct snd_pcm_runtime *runtime = substream->runtime;
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struct n64audio *priv = substream->pcm->private_data;
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u32 rate;
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rate = ((2 * AI_NTSC_DACRATE / runtime->rate) + 1) / 2 - 1;
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n64audio_write_reg(priv, AI_RATE_REG, rate);
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rate /= 66;
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if (rate > 16)
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rate = 16;
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n64audio_write_reg(priv, AI_BITCLOCK_REG, rate - 1);
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spin_lock_irq(&priv->chan.lock);
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/* Setup the pseudo-dma transfer pointers. */
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priv->chan.pos = 0;
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priv->chan.nextpos = 0;
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priv->chan.substream = substream;
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priv->chan.writesize = snd_pcm_lib_period_bytes(substream);
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priv->chan.bufsize = snd_pcm_lib_buffer_bytes(substream);
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spin_unlock_irq(&priv->chan.lock);
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return 0;
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}
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static int n64audio_pcm_trigger(struct snd_pcm_substream *substream,
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int cmd)
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{
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struct n64audio *priv = substream->pcm->private_data;
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switch (cmd) {
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case SNDRV_PCM_TRIGGER_START:
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n64audio_push(substream->pcm->private_data);
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n64audio_write_reg(priv, AI_CONTROL_REG, 1);
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n64mi_write_reg(priv, MI_MASK_REG, MI_MASK_SET_AI);
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break;
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case SNDRV_PCM_TRIGGER_STOP:
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n64audio_write_reg(priv, AI_CONTROL_REG, 0);
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n64mi_write_reg(priv, MI_MASK_REG, MI_MASK_CLR_AI);
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static snd_pcm_uframes_t n64audio_pcm_pointer(struct snd_pcm_substream *substream)
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{
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struct n64audio *priv = substream->pcm->private_data;
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return bytes_to_frames(substream->runtime,
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priv->chan.pos);
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}
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static int n64audio_pcm_close(struct snd_pcm_substream *substream)
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{
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struct n64audio *priv = substream->pcm->private_data;
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priv->chan.substream = NULL;
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return 0;
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}
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static const struct snd_pcm_ops n64audio_pcm_ops = {
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.open = n64audio_pcm_open,
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.prepare = n64audio_pcm_prepare,
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.trigger = n64audio_pcm_trigger,
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.pointer = n64audio_pcm_pointer,
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.close = n64audio_pcm_close,
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};
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/*
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* The target device is embedded and RAM-constrained. We save RAM
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* by initializing in __init code that gets dropped late in boot.
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* For the same reason there is no module or unloading support.
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*/
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static int __init n64audio_probe(struct platform_device *pdev)
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{
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struct snd_card *card;
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struct snd_pcm *pcm;
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struct n64audio *priv;
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struct resource *res;
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int err;
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err = snd_card_new(&pdev->dev, SNDRV_DEFAULT_IDX1,
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SNDRV_DEFAULT_STR1,
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THIS_MODULE, sizeof(*priv), &card);
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if (err < 0)
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return err;
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priv = card->private_data;
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spin_lock_init(&priv->chan.lock);
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priv->card = card;
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priv->ring_base = dma_alloc_coherent(card->dev, 32 * 1024, &priv->ring_base_dma,
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GFP_DMA|GFP_KERNEL);
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if (!priv->ring_base) {
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err = -ENOMEM;
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goto fail_card;
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}
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priv->mi_reg_base = devm_platform_ioremap_resource(pdev, 0);
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if (!priv->mi_reg_base) {
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err = -EINVAL;
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goto fail_dma_alloc;
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}
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priv->ai_reg_base = devm_platform_ioremap_resource(pdev, 1);
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if (!priv->ai_reg_base) {
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err = -EINVAL;
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goto fail_dma_alloc;
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}
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err = snd_pcm_new(card, "N64 Audio", 0, 1, 0, &pcm);
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if (err < 0)
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goto fail_dma_alloc;
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pcm->private_data = priv;
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strcpy(pcm->name, "N64 Audio");
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snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &n64audio_pcm_ops);
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snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, card->dev, 0, 0);
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strcpy(card->driver, "N64 Audio");
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strcpy(card->shortname, "N64 Audio");
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strcpy(card->longname, "N64 Audio");
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res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
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if (devm_request_irq(&pdev->dev, res->start, n64audio_isr,
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IRQF_SHARED, "N64 Audio", priv)) {
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err = -EBUSY;
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goto fail_dma_alloc;
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}
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err = snd_card_register(card);
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if (err < 0)
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goto fail_dma_alloc;
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return 0;
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fail_dma_alloc:
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dma_free_coherent(card->dev, 32 * 1024, priv->ring_base, priv->ring_base_dma);
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fail_card:
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snd_card_free(card);
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return err;
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}
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static struct platform_driver n64audio_driver = {
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.driver = {
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.name = "n64audio",
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},
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};
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static int __init n64audio_init(void)
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{
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return platform_driver_probe(&n64audio_driver, n64audio_probe);
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}
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module_init(n64audio_init);
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