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	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:
		
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					 3 changed files with 380 additions and 0 deletions
				
			
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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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						 | 
				
			
			
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										372
									
								
								sound/mips/snd-n64.c
									
									
									
									
									
										Normal file
									
								
							
							
						
						
									
										372
									
								
								sound/mips/snd-n64.c
									
									
									
									
									
										Normal file
									
								
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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;
 | 
			
		||||
	}
 | 
			
		||||
 | 
			
		||||
	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);
 | 
			
		||||
		Loading…
	
		Reference in a new issue