Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1697 insertions, 0 deletions

diff --git a/sound/pci/nm256/nm256.c b/sound/pci/nm256/nm256.c
new file mode 100644
index 000000000..f99a1e96e
--- /dev/null
+++ b/sound/pci/nm256/nm256.c
@@ -0,0 +1,1697 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* 
+ * Driver for NeoMagic 256AV and 256ZX chipsets.
+ * Copyright (c) 2000 by Takashi Iwai <tiwai@suse.de>
+ *
+ * Based on nm256_audio.c OSS driver in linux kernel.
+ * The original author of OSS nm256 driver wishes to remain anonymous,
+ * so I just put my acknoledgment to him/her here.
+ * The original author's web page is found at
+ *	http://www.uglx.org/sony.html
+ */
+  
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/control.h>
+#include <sound/pcm.h>
+#include <sound/ac97_codec.h>
+#include <sound/initval.h>
+
+#define CARD_NAME "NeoMagic 256AV/ZX"
+#define DRIVER_NAME "NM256"
+
+MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
+MODULE_DESCRIPTION("NeoMagic NM256AV/ZX");
+MODULE_LICENSE("GPL");
+
+/*
+ * some compile conditions.
+ */
+
+static int index = SNDRV_DEFAULT_IDX1;	/* Index */
+static char *id = SNDRV_DEFAULT_STR1;	/* ID for this card */
+static int playback_bufsize = 16;
+static int capture_bufsize = 16;
+static bool force_ac97;			/* disabled as default */
+static int buffer_top;			/* not specified */
+static bool use_cache;			/* disabled */
+static bool vaio_hack;			/* disabled */
+static bool reset_workaround;
+static bool reset_workaround_2;
+
+module_param(index, int, 0444);
+MODULE_PARM_DESC(index, "Index value for " CARD_NAME " soundcard.");
+module_param(id, charp, 0444);
+MODULE_PARM_DESC(id, "ID string for " CARD_NAME " soundcard.");
+module_param(playback_bufsize, int, 0444);
+MODULE_PARM_DESC(playback_bufsize, "DAC frame size in kB for " CARD_NAME " soundcard.");
+module_param(capture_bufsize, int, 0444);
+MODULE_PARM_DESC(capture_bufsize, "ADC frame size in kB for " CARD_NAME " soundcard.");
+module_param(force_ac97, bool, 0444);
+MODULE_PARM_DESC(force_ac97, "Force to use AC97 codec for " CARD_NAME " soundcard.");
+module_param(buffer_top, int, 0444);
+MODULE_PARM_DESC(buffer_top, "Set the top address of audio buffer for " CARD_NAME " soundcard.");
+module_param(use_cache, bool, 0444);
+MODULE_PARM_DESC(use_cache, "Enable the cache for coefficient table access.");
+module_param(vaio_hack, bool, 0444);
+MODULE_PARM_DESC(vaio_hack, "Enable workaround for Sony VAIO notebooks.");
+module_param(reset_workaround, bool, 0444);
+MODULE_PARM_DESC(reset_workaround, "Enable AC97 RESET workaround for some laptops.");
+module_param(reset_workaround_2, bool, 0444);
+MODULE_PARM_DESC(reset_workaround_2, "Enable extended AC97 RESET workaround for some other laptops.");
+
+/* just for backward compatibility */
+static bool enable;
+module_param(enable, bool, 0444);
+
+
+
+/*
+ * hw definitions
+ */
+
+/* The BIOS signature. */
+#define NM_SIGNATURE 0x4e4d0000
+/* Signature mask. */
+#define NM_SIG_MASK 0xffff0000
+
+/* Size of the second memory area. */
+#define NM_PORT2_SIZE 4096
+
+/* The base offset of the mixer in the second memory area. */
+#define NM_MIXER_OFFSET 0x600
+
+/* The maximum size of a coefficient entry. */
+#define NM_MAX_PLAYBACK_COEF_SIZE	0x5000
+#define NM_MAX_RECORD_COEF_SIZE		0x1260
+
+/* The interrupt register. */
+#define NM_INT_REG 0xa04
+/* And its bits. */
+#define NM_PLAYBACK_INT 0x40
+#define NM_RECORD_INT 0x100
+#define NM_MISC_INT_1 0x4000
+#define NM_MISC_INT_2 0x1
+#define NM_ACK_INT(chip, X) snd_nm256_writew(chip, NM_INT_REG, (X) << 1)
+
+/* The AV's "mixer ready" status bit and location. */
+#define NM_MIXER_STATUS_OFFSET 0xa04
+#define NM_MIXER_READY_MASK 0x0800
+#define NM_MIXER_PRESENCE 0xa06
+#define NM_PRESENCE_MASK 0x0050
+#define NM_PRESENCE_VALUE 0x0040
+
+/*
+ * For the ZX.  It uses the same interrupt register, but it holds 32
+ * bits instead of 16.
+ */
+#define NM2_PLAYBACK_INT 0x10000
+#define NM2_RECORD_INT 0x80000
+#define NM2_MISC_INT_1 0x8
+#define NM2_MISC_INT_2 0x2
+#define NM2_ACK_INT(chip, X) snd_nm256_writel(chip, NM_INT_REG, (X))
+
+/* The ZX's "mixer ready" status bit and location. */
+#define NM2_MIXER_STATUS_OFFSET 0xa06
+#define NM2_MIXER_READY_MASK 0x0800
+
+/* The playback registers start from here. */
+#define NM_PLAYBACK_REG_OFFSET 0x0
+/* The record registers start from here. */
+#define NM_RECORD_REG_OFFSET 0x200
+
+/* The rate register is located 2 bytes from the start of the register area. */
+#define NM_RATE_REG_OFFSET 2
+
+/* Mono/stereo flag, number of bits on playback, and rate mask. */
+#define NM_RATE_STEREO 1
+#define NM_RATE_BITS_16 2
+#define NM_RATE_MASK 0xf0
+
+/* Playback enable register. */
+#define NM_PLAYBACK_ENABLE_REG (NM_PLAYBACK_REG_OFFSET + 0x1)
+#define NM_PLAYBACK_ENABLE_FLAG 1
+#define NM_PLAYBACK_ONESHOT 2
+#define NM_PLAYBACK_FREERUN 4
+
+/* Mutes the audio output. */
+#define NM_AUDIO_MUTE_REG (NM_PLAYBACK_REG_OFFSET + 0x18)
+#define NM_AUDIO_MUTE_LEFT 0x8000
+#define NM_AUDIO_MUTE_RIGHT 0x0080
+
+/* Recording enable register. */
+#define NM_RECORD_ENABLE_REG (NM_RECORD_REG_OFFSET + 0)
+#define NM_RECORD_ENABLE_FLAG 1
+#define NM_RECORD_FREERUN 2
+
+/* coefficient buffer pointer */
+#define NM_COEFF_START_OFFSET	0x1c
+#define NM_COEFF_END_OFFSET	0x20
+
+/* DMA buffer offsets */
+#define NM_RBUFFER_START (NM_RECORD_REG_OFFSET + 0x4)
+#define NM_RBUFFER_END   (NM_RECORD_REG_OFFSET + 0x10)
+#define NM_RBUFFER_WMARK (NM_RECORD_REG_OFFSET + 0xc)
+#define NM_RBUFFER_CURRP (NM_RECORD_REG_OFFSET + 0x8)
+
+#define NM_PBUFFER_START (NM_PLAYBACK_REG_OFFSET + 0x4)
+#define NM_PBUFFER_END   (NM_PLAYBACK_REG_OFFSET + 0x14)
+#define NM_PBUFFER_WMARK (NM_PLAYBACK_REG_OFFSET + 0xc)
+#define NM_PBUFFER_CURRP (NM_PLAYBACK_REG_OFFSET + 0x8)
+
+struct nm256_stream {
+
+	struct nm256 *chip;
+	struct snd_pcm_substream *substream;
+	int running;
+	int suspended;
+	
+	u32 buf;	/* offset from chip->buffer */
+	int bufsize;	/* buffer size in bytes */
+	void __iomem *bufptr;		/* mapped pointer */
+	unsigned long bufptr_addr;	/* physical address of the mapped pointer */
+
+	int dma_size;		/* buffer size of the substream in bytes */
+	int period_size;	/* period size in bytes */
+	int periods;		/* # of periods */
+	int shift;		/* bit shifts */
+	int cur_period;		/* current period # */
+
+};
+
+struct nm256 {
+	
+	struct snd_card *card;
+
+	void __iomem *cport;		/* control port */
+	unsigned long cport_addr;	/* physical address */
+
+	void __iomem *buffer;		/* buffer */
+	unsigned long buffer_addr;	/* buffer phyiscal address */
+
+	u32 buffer_start;		/* start offset from pci resource 0 */
+	u32 buffer_end;			/* end offset */
+	u32 buffer_size;		/* total buffer size */
+
+	u32 all_coeff_buf;		/* coefficient buffer */
+	u32 coeff_buf[2];		/* coefficient buffer for each stream */
+
+	unsigned int coeffs_current: 1;	/* coeff. table is loaded? */
+	unsigned int use_cache: 1;	/* use one big coef. table */
+	unsigned int reset_workaround: 1; /* Workaround for some laptops to avoid freeze */
+	unsigned int reset_workaround_2: 1; /* Extended workaround for some other laptops to avoid freeze */
+	unsigned int in_resume: 1;
+
+	int mixer_base;			/* register offset of ac97 mixer */
+	int mixer_status_offset;	/* offset of mixer status reg. */
+	int mixer_status_mask;		/* bit mask to test the mixer status */
+
+	int irq;
+	int irq_acks;
+	irq_handler_t interrupt;
+	int badintrcount;		/* counter to check bogus interrupts */
+	struct mutex irq_mutex;
+
+	struct nm256_stream streams[2];
+
+	struct snd_ac97 *ac97;
+	unsigned short *ac97_regs; /* register caches, only for valid regs */
+
+	struct snd_pcm *pcm;
+
+	struct pci_dev *pci;
+
+	spinlock_t reg_lock;
+
+};
+
+
+/*
+ * include coefficient table
+ */
+#include "nm256_coef.c"
+
+
+/*
+ * PCI ids
+ */
+static const struct pci_device_id snd_nm256_ids[] = {
+	{PCI_VDEVICE(NEOMAGIC, PCI_DEVICE_ID_NEOMAGIC_NM256AV_AUDIO), 0},
+	{PCI_VDEVICE(NEOMAGIC, PCI_DEVICE_ID_NEOMAGIC_NM256ZX_AUDIO), 0},
+	{PCI_VDEVICE(NEOMAGIC, PCI_DEVICE_ID_NEOMAGIC_NM256XL_PLUS_AUDIO), 0},
+	{0,},
+};
+
+MODULE_DEVICE_TABLE(pci, snd_nm256_ids);
+
+
+/*
+ * lowlvel stuffs
+ */
+
+static inline u8
+snd_nm256_readb(struct nm256 *chip, int offset)
+{
+	return readb(chip->cport + offset);
+}
+
+static inline u16
+snd_nm256_readw(struct nm256 *chip, int offset)
+{
+	return readw(chip->cport + offset);
+}
+
+static inline u32
+snd_nm256_readl(struct nm256 *chip, int offset)
+{
+	return readl(chip->cport + offset);
+}
+
+static inline void
+snd_nm256_writeb(struct nm256 *chip, int offset, u8 val)
+{
+	writeb(val, chip->cport + offset);
+}
+
+static inline void
+snd_nm256_writew(struct nm256 *chip, int offset, u16 val)
+{
+	writew(val, chip->cport + offset);
+}
+
+static inline void
+snd_nm256_writel(struct nm256 *chip, int offset, u32 val)
+{
+	writel(val, chip->cport + offset);
+}
+
+static inline void
+snd_nm256_write_buffer(struct nm256 *chip, const void *src, int offset, int size)
+{
+	offset -= chip->buffer_start;
+#ifdef CONFIG_SND_DEBUG
+	if (offset < 0 || offset >= chip->buffer_size) {
+		dev_err(chip->card->dev,
+			"write_buffer invalid offset = %d size = %d\n",
+			   offset, size);
+		return;
+	}
+#endif
+	memcpy_toio(chip->buffer + offset, src, size);
+}
+
+/*
+ * coefficient handlers -- what a magic!
+ */
+
+static u16
+snd_nm256_get_start_offset(int which)
+{
+	u16 offset = 0;
+	while (which-- > 0)
+		offset += coefficient_sizes[which];
+	return offset;
+}
+
+static void
+snd_nm256_load_one_coefficient(struct nm256 *chip, int stream, u32 port, int which)
+{
+	u32 coeff_buf = chip->coeff_buf[stream];
+	u16 offset = snd_nm256_get_start_offset(which);
+	u16 size = coefficient_sizes[which];
+
+	snd_nm256_write_buffer(chip, coefficients + offset, coeff_buf, size);
+	snd_nm256_writel(chip, port, coeff_buf);
+	/* ???  Record seems to behave differently than playback.  */
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK)
+		size--;
+	snd_nm256_writel(chip, port + 4, coeff_buf + size);
+}
+
+static void
+snd_nm256_load_coefficient(struct nm256 *chip, int stream, int number)
+{
+	/* The enable register for the specified engine.  */
+	u32 poffset = (stream == SNDRV_PCM_STREAM_CAPTURE ?
+		       NM_RECORD_ENABLE_REG : NM_PLAYBACK_ENABLE_REG);
+	u32 addr = NM_COEFF_START_OFFSET;
+
+	addr += (stream == SNDRV_PCM_STREAM_CAPTURE ?
+		 NM_RECORD_REG_OFFSET : NM_PLAYBACK_REG_OFFSET);
+
+	if (snd_nm256_readb(chip, poffset) & 1) {
+		dev_dbg(chip->card->dev,
+			"NM256: Engine was enabled while loading coefficients!\n");
+		return;
+	}
+
+	/* The recording engine uses coefficient values 8-15.  */
+	number &= 7;
+	if (stream == SNDRV_PCM_STREAM_CAPTURE)
+		number += 8;
+
+	if (! chip->use_cache) {
+		snd_nm256_load_one_coefficient(chip, stream, addr, number);
+		return;
+	}
+	if (! chip->coeffs_current) {
+		snd_nm256_write_buffer(chip, coefficients, chip->all_coeff_buf,
+				       NM_TOTAL_COEFF_COUNT * 4);
+		chip->coeffs_current = 1;
+	} else {
+		u32 base = chip->all_coeff_buf;
+		u32 offset = snd_nm256_get_start_offset(number);
+		u32 end_offset = offset + coefficient_sizes[number];
+		snd_nm256_writel(chip, addr, base + offset);
+		if (stream == SNDRV_PCM_STREAM_PLAYBACK)
+			end_offset--;
+		snd_nm256_writel(chip, addr + 4, base + end_offset);
+	}
+}
+
+
+/* The actual rates supported by the card. */
+static const unsigned int samplerates[8] = {
+	8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000,
+};
+static const struct snd_pcm_hw_constraint_list constraints_rates = {
+	.count = ARRAY_SIZE(samplerates), 
+	.list = samplerates,
+	.mask = 0,
+};
+
+/*
+ * return the index of the target rate
+ */
+static int
+snd_nm256_fixed_rate(unsigned int rate)
+{
+	unsigned int i;
+	for (i = 0; i < ARRAY_SIZE(samplerates); i++) {
+		if (rate == samplerates[i])
+			return i;
+	}
+	snd_BUG();
+	return 0;
+}
+
+/*
+ * set sample rate and format
+ */
+static void
+snd_nm256_set_format(struct nm256 *chip, struct nm256_stream *s,
+		     struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	int rate_index = snd_nm256_fixed_rate(runtime->rate);
+	unsigned char ratebits = (rate_index << 4) & NM_RATE_MASK;
+
+	s->shift = 0;
+	if (snd_pcm_format_width(runtime->format) == 16) {
+		ratebits |= NM_RATE_BITS_16;
+		s->shift++;
+	}
+	if (runtime->channels > 1) {
+		ratebits |= NM_RATE_STEREO;
+		s->shift++;
+	}
+
+	runtime->rate = samplerates[rate_index];
+
+	switch (substream->stream) {
+	case SNDRV_PCM_STREAM_PLAYBACK:
+		snd_nm256_load_coefficient(chip, 0, rate_index); /* 0 = playback */
+		snd_nm256_writeb(chip,
+				 NM_PLAYBACK_REG_OFFSET + NM_RATE_REG_OFFSET,
+				 ratebits);
+		break;
+	case SNDRV_PCM_STREAM_CAPTURE:
+		snd_nm256_load_coefficient(chip, 1, rate_index); /* 1 = record */
+		snd_nm256_writeb(chip,
+				 NM_RECORD_REG_OFFSET + NM_RATE_REG_OFFSET,
+				 ratebits);
+		break;
+	}
+}
+
+/* acquire interrupt */
+static int snd_nm256_acquire_irq(struct nm256 *chip)
+{
+	mutex_lock(&chip->irq_mutex);
+	if (chip->irq < 0) {
+		if (request_irq(chip->pci->irq, chip->interrupt, IRQF_SHARED,
+				KBUILD_MODNAME, chip)) {
+			dev_err(chip->card->dev,
+				"unable to grab IRQ %d\n", chip->pci->irq);
+			mutex_unlock(&chip->irq_mutex);
+			return -EBUSY;
+		}
+		chip->irq = chip->pci->irq;
+		chip->card->sync_irq = chip->irq;
+	}
+	chip->irq_acks++;
+	mutex_unlock(&chip->irq_mutex);
+	return 0;
+}
+
+/* release interrupt */
+static void snd_nm256_release_irq(struct nm256 *chip)
+{
+	mutex_lock(&chip->irq_mutex);
+	if (chip->irq_acks > 0)
+		chip->irq_acks--;
+	if (chip->irq_acks == 0 && chip->irq >= 0) {
+		free_irq(chip->irq, chip);
+		chip->irq = -1;
+		chip->card->sync_irq = -1;
+	}
+	mutex_unlock(&chip->irq_mutex);
+}
+
+/*
+ * start / stop
+ */
+
+/* update the watermark (current period) */
+static void snd_nm256_pcm_mark(struct nm256 *chip, struct nm256_stream *s, int reg)
+{
+	s->cur_period++;
+	s->cur_period %= s->periods;
+	snd_nm256_writel(chip, reg, s->buf + s->cur_period * s->period_size);
+}
+
+#define snd_nm256_playback_mark(chip, s) snd_nm256_pcm_mark(chip, s, NM_PBUFFER_WMARK)
+#define snd_nm256_capture_mark(chip, s)  snd_nm256_pcm_mark(chip, s, NM_RBUFFER_WMARK)
+
+static void
+snd_nm256_playback_start(struct nm256 *chip, struct nm256_stream *s,
+			 struct snd_pcm_substream *substream)
+{
+	/* program buffer pointers */
+	snd_nm256_writel(chip, NM_PBUFFER_START, s->buf);
+	snd_nm256_writel(chip, NM_PBUFFER_END, s->buf + s->dma_size - (1 << s->shift));
+	snd_nm256_writel(chip, NM_PBUFFER_CURRP, s->buf);
+	snd_nm256_playback_mark(chip, s);
+
+	/* Enable playback engine and interrupts. */
+	snd_nm256_writeb(chip, NM_PLAYBACK_ENABLE_REG,
+			 NM_PLAYBACK_ENABLE_FLAG | NM_PLAYBACK_FREERUN);
+	/* Enable both channels. */
+	snd_nm256_writew(chip, NM_AUDIO_MUTE_REG, 0x0);
+}
+
+static void
+snd_nm256_capture_start(struct nm256 *chip, struct nm256_stream *s,
+			struct snd_pcm_substream *substream)
+{
+	/* program buffer pointers */
+	snd_nm256_writel(chip, NM_RBUFFER_START, s->buf);
+	snd_nm256_writel(chip, NM_RBUFFER_END, s->buf + s->dma_size);
+	snd_nm256_writel(chip, NM_RBUFFER_CURRP, s->buf);
+	snd_nm256_capture_mark(chip, s);
+
+	/* Enable playback engine and interrupts. */
+	snd_nm256_writeb(chip, NM_RECORD_ENABLE_REG,
+			 NM_RECORD_ENABLE_FLAG | NM_RECORD_FREERUN);
+}
+
+/* Stop the play engine. */
+static void
+snd_nm256_playback_stop(struct nm256 *chip)
+{
+	/* Shut off sound from both channels. */
+	snd_nm256_writew(chip, NM_AUDIO_MUTE_REG,
+			 NM_AUDIO_MUTE_LEFT | NM_AUDIO_MUTE_RIGHT);
+	/* Disable play engine. */
+	snd_nm256_writeb(chip, NM_PLAYBACK_ENABLE_REG, 0);
+}
+
+static void
+snd_nm256_capture_stop(struct nm256 *chip)
+{
+	/* Disable recording engine. */
+	snd_nm256_writeb(chip, NM_RECORD_ENABLE_REG, 0);
+}
+
+static int
+snd_nm256_playback_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct nm256 *chip = snd_pcm_substream_chip(substream);
+	struct nm256_stream *s = substream->runtime->private_data;
+	int err = 0;
+
+	if (snd_BUG_ON(!s))
+		return -ENXIO;
+
+	spin_lock(&chip->reg_lock);
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_RESUME:
+		s->suspended = 0;
+		fallthrough;
+	case SNDRV_PCM_TRIGGER_START:
+		if (! s->running) {
+			snd_nm256_playback_start(chip, s, substream);
+			s->running = 1;
+		}
+		break;
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+		s->suspended = 1;
+		fallthrough;
+	case SNDRV_PCM_TRIGGER_STOP:
+		if (s->running) {
+			snd_nm256_playback_stop(chip);
+			s->running = 0;
+		}
+		break;
+	default:
+		err = -EINVAL;
+		break;
+	}
+	spin_unlock(&chip->reg_lock);
+	return err;
+}
+
+static int
+snd_nm256_capture_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct nm256 *chip = snd_pcm_substream_chip(substream);
+	struct nm256_stream *s = substream->runtime->private_data;
+	int err = 0;
+
+	if (snd_BUG_ON(!s))
+		return -ENXIO;
+
+	spin_lock(&chip->reg_lock);
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+		if (! s->running) {
+			snd_nm256_capture_start(chip, s, substream);
+			s->running = 1;
+		}
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+		if (s->running) {
+			snd_nm256_capture_stop(chip);
+			s->running = 0;
+		}
+		break;
+	default:
+		err = -EINVAL;
+		break;
+	}
+	spin_unlock(&chip->reg_lock);
+	return err;
+}
+
+
+/*
+ * prepare playback/capture channel
+ */
+static int snd_nm256_pcm_prepare(struct snd_pcm_substream *substream)
+{
+	struct nm256 *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct nm256_stream *s = runtime->private_data;
+
+	if (snd_BUG_ON(!s))
+		return -ENXIO;
+	s->dma_size = frames_to_bytes(runtime, substream->runtime->buffer_size);
+	s->period_size = frames_to_bytes(runtime, substream->runtime->period_size);
+	s->periods = substream->runtime->periods;
+	s->cur_period = 0;
+
+	spin_lock_irq(&chip->reg_lock);
+	s->running = 0;
+	snd_nm256_set_format(chip, s, substream);
+	spin_unlock_irq(&chip->reg_lock);
+
+	return 0;
+}
+
+
+/*
+ * get the current pointer
+ */
+static snd_pcm_uframes_t
+snd_nm256_playback_pointer(struct snd_pcm_substream *substream)
+{
+	struct nm256 *chip = snd_pcm_substream_chip(substream);
+	struct nm256_stream *s = substream->runtime->private_data;
+	unsigned long curp;
+
+	if (snd_BUG_ON(!s))
+		return 0;
+	curp = snd_nm256_readl(chip, NM_PBUFFER_CURRP) - (unsigned long)s->buf;
+	curp %= s->dma_size;
+	return bytes_to_frames(substream->runtime, curp);
+}
+
+static snd_pcm_uframes_t
+snd_nm256_capture_pointer(struct snd_pcm_substream *substream)
+{
+	struct nm256 *chip = snd_pcm_substream_chip(substream);
+	struct nm256_stream *s = substream->runtime->private_data;
+	unsigned long curp;
+
+	if (snd_BUG_ON(!s))
+		return 0;
+	curp = snd_nm256_readl(chip, NM_RBUFFER_CURRP) - (unsigned long)s->buf;
+	curp %= s->dma_size;	
+	return bytes_to_frames(substream->runtime, curp);
+}
+
+/* Remapped I/O space can be accessible as pointer on i386 */
+/* This might be changed in the future */
+#ifndef __i386__
+/*
+ * silence / copy for playback
+ */
+static int
+snd_nm256_playback_silence(struct snd_pcm_substream *substream,
+			   int channel, unsigned long pos, unsigned long count)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct nm256_stream *s = runtime->private_data;
+
+	memset_io(s->bufptr + pos, 0, count);
+	return 0;
+}
+
+static int
+snd_nm256_playback_copy(struct snd_pcm_substream *substream,
+			int channel, unsigned long pos,
+			void __user *src, unsigned long count)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct nm256_stream *s = runtime->private_data;
+
+	if (copy_from_user_toio(s->bufptr + pos, src, count))
+		return -EFAULT;
+	return 0;
+}
+
+static int
+snd_nm256_playback_copy_kernel(struct snd_pcm_substream *substream,
+			       int channel, unsigned long pos,
+			       void *src, unsigned long count)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct nm256_stream *s = runtime->private_data;
+
+	memcpy_toio(s->bufptr + pos, src, count);
+	return 0;
+}
+
+/*
+ * copy to user
+ */
+static int
+snd_nm256_capture_copy(struct snd_pcm_substream *substream,
+		       int channel, unsigned long pos,
+		       void __user *dst, unsigned long count)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct nm256_stream *s = runtime->private_data;
+
+	if (copy_to_user_fromio(dst, s->bufptr + pos, count))
+		return -EFAULT;
+	return 0;
+}
+
+static int
+snd_nm256_capture_copy_kernel(struct snd_pcm_substream *substream,
+			      int channel, unsigned long pos,
+			      void *dst, unsigned long count)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct nm256_stream *s = runtime->private_data;
+
+	memcpy_fromio(dst, s->bufptr + pos, count);
+	return 0;
+}
+
+#endif /* !__i386__ */
+
+
+/*
+ * update playback/capture watermarks
+ */
+
+/* spinlock held! */
+static void
+snd_nm256_playback_update(struct nm256 *chip)
+{
+	struct nm256_stream *s;
+
+	s = &chip->streams[SNDRV_PCM_STREAM_PLAYBACK];
+	if (s->running && s->substream) {
+		spin_unlock(&chip->reg_lock);
+		snd_pcm_period_elapsed(s->substream);
+		spin_lock(&chip->reg_lock);
+		snd_nm256_playback_mark(chip, s);
+	}
+}
+
+/* spinlock held! */
+static void
+snd_nm256_capture_update(struct nm256 *chip)
+{
+	struct nm256_stream *s;
+
+	s = &chip->streams[SNDRV_PCM_STREAM_CAPTURE];
+	if (s->running && s->substream) {
+		spin_unlock(&chip->reg_lock);
+		snd_pcm_period_elapsed(s->substream);
+		spin_lock(&chip->reg_lock);
+		snd_nm256_capture_mark(chip, s);
+	}
+}
+
+/*
+ * hardware info
+ */
+static const struct snd_pcm_hardware snd_nm256_playback =
+{
+	.info =			SNDRV_PCM_INFO_MMAP_IOMEM |SNDRV_PCM_INFO_MMAP_VALID |
+				SNDRV_PCM_INFO_INTERLEAVED |
+				/*SNDRV_PCM_INFO_PAUSE |*/
+				SNDRV_PCM_INFO_RESUME,
+	.formats =		SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE,
+	.rates =		SNDRV_PCM_RATE_KNOT/*24k*/ | SNDRV_PCM_RATE_8000_48000,
+	.rate_min =		8000,
+	.rate_max =		48000,
+	.channels_min =		1,
+	.channels_max =		2,
+	.periods_min =		2,
+	.periods_max =		1024,
+	.buffer_bytes_max =	128 * 1024,
+	.period_bytes_min =	256,
+	.period_bytes_max =	128 * 1024,
+};
+
+static const struct snd_pcm_hardware snd_nm256_capture =
+{
+	.info =			SNDRV_PCM_INFO_MMAP_IOMEM | SNDRV_PCM_INFO_MMAP_VALID |
+				SNDRV_PCM_INFO_INTERLEAVED |
+				/*SNDRV_PCM_INFO_PAUSE |*/
+				SNDRV_PCM_INFO_RESUME,
+	.formats =		SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE,
+	.rates =		SNDRV_PCM_RATE_KNOT/*24k*/ | SNDRV_PCM_RATE_8000_48000,
+	.rate_min =		8000,
+	.rate_max =		48000,
+	.channels_min =		1,
+	.channels_max =		2,
+	.periods_min =		2,
+	.periods_max =		1024,
+	.buffer_bytes_max =	128 * 1024,
+	.period_bytes_min =	256,
+	.period_bytes_max =	128 * 1024,
+};
+
+
+/* set dma transfer size */
+static int snd_nm256_pcm_hw_params(struct snd_pcm_substream *substream,
+				   struct snd_pcm_hw_params *hw_params)
+{
+	/* area and addr are already set and unchanged */
+	substream->runtime->dma_bytes = params_buffer_bytes(hw_params);
+	return 0;
+}
+
+/*
+ * open
+ */
+static void snd_nm256_setup_stream(struct nm256 *chip, struct nm256_stream *s,
+				   struct snd_pcm_substream *substream,
+				   const struct snd_pcm_hardware *hw_ptr)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+
+	s->running = 0;
+	runtime->hw = *hw_ptr;
+	runtime->hw.buffer_bytes_max = s->bufsize;
+	runtime->hw.period_bytes_max = s->bufsize / 2;
+	runtime->dma_area = (void __force *) s->bufptr;
+	runtime->dma_addr = s->bufptr_addr;
+	runtime->dma_bytes = s->bufsize;
+	runtime->private_data = s;
+	s->substream = substream;
+
+	snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
+				   &constraints_rates);
+}
+
+static int
+snd_nm256_playback_open(struct snd_pcm_substream *substream)
+{
+	struct nm256 *chip = snd_pcm_substream_chip(substream);
+
+	if (snd_nm256_acquire_irq(chip) < 0)
+		return -EBUSY;
+	snd_nm256_setup_stream(chip, &chip->streams[SNDRV_PCM_STREAM_PLAYBACK],
+			       substream, &snd_nm256_playback);
+	return 0;
+}
+
+static int
+snd_nm256_capture_open(struct snd_pcm_substream *substream)
+{
+	struct nm256 *chip = snd_pcm_substream_chip(substream);
+
+	if (snd_nm256_acquire_irq(chip) < 0)
+		return -EBUSY;
+	snd_nm256_setup_stream(chip, &chip->streams[SNDRV_PCM_STREAM_CAPTURE],
+			       substream, &snd_nm256_capture);
+	return 0;
+}
+
+/*
+ * close - we don't have to do special..
+ */
+static int
+snd_nm256_playback_close(struct snd_pcm_substream *substream)
+{
+	struct nm256 *chip = snd_pcm_substream_chip(substream);
+
+	snd_nm256_release_irq(chip);
+	return 0;
+}
+
+
+static int
+snd_nm256_capture_close(struct snd_pcm_substream *substream)
+{
+	struct nm256 *chip = snd_pcm_substream_chip(substream);
+
+	snd_nm256_release_irq(chip);
+	return 0;
+}
+
+/*
+ * create a pcm instance
+ */
+static const struct snd_pcm_ops snd_nm256_playback_ops = {
+	.open =		snd_nm256_playback_open,
+	.close =	snd_nm256_playback_close,
+	.hw_params =	snd_nm256_pcm_hw_params,
+	.prepare =	snd_nm256_pcm_prepare,
+	.trigger =	snd_nm256_playback_trigger,
+	.pointer =	snd_nm256_playback_pointer,
+#ifndef __i386__
+	.copy_user =	snd_nm256_playback_copy,
+	.copy_kernel =	snd_nm256_playback_copy_kernel,
+	.fill_silence =	snd_nm256_playback_silence,
+#endif
+	.mmap =		snd_pcm_lib_mmap_iomem,
+};
+
+static const struct snd_pcm_ops snd_nm256_capture_ops = {
+	.open =		snd_nm256_capture_open,
+	.close =	snd_nm256_capture_close,
+	.hw_params =	snd_nm256_pcm_hw_params,
+	.prepare =	snd_nm256_pcm_prepare,
+	.trigger =	snd_nm256_capture_trigger,
+	.pointer =	snd_nm256_capture_pointer,
+#ifndef __i386__
+	.copy_user =	snd_nm256_capture_copy,
+	.copy_kernel =	snd_nm256_capture_copy_kernel,
+#endif
+	.mmap =		snd_pcm_lib_mmap_iomem,
+};
+
+static int
+snd_nm256_pcm(struct nm256 *chip, int device)
+{
+	struct snd_pcm *pcm;
+	int i, err;
+
+	for (i = 0; i < 2; i++) {
+		struct nm256_stream *s = &chip->streams[i];
+		s->bufptr = chip->buffer + (s->buf - chip->buffer_start);
+		s->bufptr_addr = chip->buffer_addr + (s->buf - chip->buffer_start);
+	}
+
+	err = snd_pcm_new(chip->card, chip->card->driver, device,
+			  1, 1, &pcm);
+	if (err < 0)
+		return err;
+
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_nm256_playback_ops);
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_nm256_capture_ops);
+
+	pcm->private_data = chip;
+	pcm->info_flags = 0;
+	chip->pcm = pcm;
+
+	return 0;
+}
+
+
+/* 
+ * Initialize the hardware. 
+ */
+static void
+snd_nm256_init_chip(struct nm256 *chip)
+{
+	/* Reset everything. */
+	snd_nm256_writeb(chip, 0x0, 0x11);
+	snd_nm256_writew(chip, 0x214, 0);
+	/* stop sounds.. */
+	//snd_nm256_playback_stop(chip);
+	//snd_nm256_capture_stop(chip);
+}
+
+
+static irqreturn_t
+snd_nm256_intr_check(struct nm256 *chip)
+{
+	if (chip->badintrcount++ > 1000) {
+		/*
+		 * I'm not sure if the best thing is to stop the card from
+		 * playing or just release the interrupt (after all, we're in
+		 * a bad situation, so doing fancy stuff may not be such a good
+		 * idea).
+		 *
+		 * I worry about the card engine continuing to play noise
+		 * over and over, however--that could become a very
+		 * obnoxious problem.  And we know that when this usually
+		 * happens things are fairly safe, it just means the user's
+		 * inserted a PCMCIA card and someone's spamming us with IRQ 9s.
+		 */
+		if (chip->streams[SNDRV_PCM_STREAM_PLAYBACK].running)
+			snd_nm256_playback_stop(chip);
+		if (chip->streams[SNDRV_PCM_STREAM_CAPTURE].running)
+			snd_nm256_capture_stop(chip);
+		chip->badintrcount = 0;
+		return IRQ_HANDLED;
+	}
+	return IRQ_NONE;
+}
+
+/* 
+ * Handle a potential interrupt for the device referred to by DEV_ID. 
+ *
+ * I don't like the cut-n-paste job here either between the two routines,
+ * but there are sufficient differences between the two interrupt handlers
+ * that parameterizing it isn't all that great either.  (Could use a macro,
+ * I suppose...yucky bleah.)
+ */
+
+static irqreturn_t
+snd_nm256_interrupt(int irq, void *dev_id)
+{
+	struct nm256 *chip = dev_id;
+	u16 status;
+	u8 cbyte;
+
+	status = snd_nm256_readw(chip, NM_INT_REG);
+
+	/* Not ours. */
+	if (status == 0)
+		return snd_nm256_intr_check(chip);
+
+	chip->badintrcount = 0;
+
+	/* Rather boring; check for individual interrupts and process them. */
+
+	spin_lock(&chip->reg_lock);
+	if (status & NM_PLAYBACK_INT) {
+		status &= ~NM_PLAYBACK_INT;
+		NM_ACK_INT(chip, NM_PLAYBACK_INT);
+		snd_nm256_playback_update(chip);
+	}
+
+	if (status & NM_RECORD_INT) {
+		status &= ~NM_RECORD_INT;
+		NM_ACK_INT(chip, NM_RECORD_INT);
+		snd_nm256_capture_update(chip);
+	}
+
+	if (status & NM_MISC_INT_1) {
+		status &= ~NM_MISC_INT_1;
+		NM_ACK_INT(chip, NM_MISC_INT_1);
+		dev_dbg(chip->card->dev, "NM256: Got misc interrupt #1\n");
+		snd_nm256_writew(chip, NM_INT_REG, 0x8000);
+		cbyte = snd_nm256_readb(chip, 0x400);
+		snd_nm256_writeb(chip, 0x400, cbyte | 2);
+	}
+
+	if (status & NM_MISC_INT_2) {
+		status &= ~NM_MISC_INT_2;
+		NM_ACK_INT(chip, NM_MISC_INT_2);
+		dev_dbg(chip->card->dev, "NM256: Got misc interrupt #2\n");
+		cbyte = snd_nm256_readb(chip, 0x400);
+		snd_nm256_writeb(chip, 0x400, cbyte & ~2);
+	}
+
+	/* Unknown interrupt. */
+	if (status) {
+		dev_dbg(chip->card->dev,
+			"NM256: Fire in the hole! Unknown status 0x%x\n",
+			   status);
+		/* Pray. */
+		NM_ACK_INT(chip, status);
+	}
+
+	spin_unlock(&chip->reg_lock);
+	return IRQ_HANDLED;
+}
+
+/*
+ * Handle a potential interrupt for the device referred to by DEV_ID.
+ * This handler is for the 256ZX, and is very similar to the non-ZX
+ * routine.
+ */
+
+static irqreturn_t
+snd_nm256_interrupt_zx(int irq, void *dev_id)
+{
+	struct nm256 *chip = dev_id;
+	u32 status;
+	u8 cbyte;
+
+	status = snd_nm256_readl(chip, NM_INT_REG);
+
+	/* Not ours. */
+	if (status == 0)
+		return snd_nm256_intr_check(chip);
+
+	chip->badintrcount = 0;
+
+	/* Rather boring; check for individual interrupts and process them. */
+
+	spin_lock(&chip->reg_lock);
+	if (status & NM2_PLAYBACK_INT) {
+		status &= ~NM2_PLAYBACK_INT;
+		NM2_ACK_INT(chip, NM2_PLAYBACK_INT);
+		snd_nm256_playback_update(chip);
+	}
+
+	if (status & NM2_RECORD_INT) {
+		status &= ~NM2_RECORD_INT;
+		NM2_ACK_INT(chip, NM2_RECORD_INT);
+		snd_nm256_capture_update(chip);
+	}
+
+	if (status & NM2_MISC_INT_1) {
+		status &= ~NM2_MISC_INT_1;
+		NM2_ACK_INT(chip, NM2_MISC_INT_1);
+		dev_dbg(chip->card->dev, "NM256: Got misc interrupt #1\n");
+		cbyte = snd_nm256_readb(chip, 0x400);
+		snd_nm256_writeb(chip, 0x400, cbyte | 2);
+	}
+
+	if (status & NM2_MISC_INT_2) {
+		status &= ~NM2_MISC_INT_2;
+		NM2_ACK_INT(chip, NM2_MISC_INT_2);
+		dev_dbg(chip->card->dev, "NM256: Got misc interrupt #2\n");
+		cbyte = snd_nm256_readb(chip, 0x400);
+		snd_nm256_writeb(chip, 0x400, cbyte & ~2);
+	}
+
+	/* Unknown interrupt. */
+	if (status) {
+		dev_dbg(chip->card->dev,
+			"NM256: Fire in the hole! Unknown status 0x%x\n",
+			   status);
+		/* Pray. */
+		NM2_ACK_INT(chip, status);
+	}
+
+	spin_unlock(&chip->reg_lock);
+	return IRQ_HANDLED;
+}
+
+/*
+ * AC97 interface
+ */
+
+/*
+ * Waits for the mixer to become ready to be written; returns a zero value
+ * if it timed out.
+ */
+static int
+snd_nm256_ac97_ready(struct nm256 *chip)
+{
+	int timeout = 10;
+	u32 testaddr;
+	u16 testb;
+
+	testaddr = chip->mixer_status_offset;
+	testb = chip->mixer_status_mask;
+
+	/* 
+	 * Loop around waiting for the mixer to become ready. 
+	 */
+	while (timeout-- > 0) {
+		if ((snd_nm256_readw(chip, testaddr) & testb) == 0)
+			return 1;
+		udelay(100);
+	}
+	return 0;
+}
+
+/* 
+ * Initial register values to be written to the AC97 mixer.
+ * While most of these are identical to the reset values, we do this
+ * so that we have most of the register contents cached--this avoids
+ * reading from the mixer directly (which seems to be problematic,
+ * probably due to ignorance).
+ */
+
+struct initialValues {
+	unsigned short reg;
+	unsigned short value;
+};
+
+static const struct initialValues nm256_ac97_init_val[] =
+{
+	{ AC97_MASTER, 		0x8000 },
+	{ AC97_HEADPHONE,	0x8000 },
+	{ AC97_MASTER_MONO,	0x8000 },
+	{ AC97_PC_BEEP,		0x8000 },
+	{ AC97_PHONE,		0x8008 },
+	{ AC97_MIC,		0x8000 },
+	{ AC97_LINE,		0x8808 },
+	{ AC97_CD,		0x8808 },
+	{ AC97_VIDEO,		0x8808 },
+	{ AC97_AUX,		0x8808 },
+	{ AC97_PCM,		0x8808 },
+	{ AC97_REC_SEL,		0x0000 },
+	{ AC97_REC_GAIN,	0x0B0B },
+	{ AC97_GENERAL_PURPOSE,	0x0000 },
+	{ AC97_3D_CONTROL,	0x8000 }, 
+	{ AC97_VENDOR_ID1, 	0x8384 },
+	{ AC97_VENDOR_ID2,	0x7609 },
+};
+
+static int nm256_ac97_idx(unsigned short reg)
+{
+	int i;
+	for (i = 0; i < ARRAY_SIZE(nm256_ac97_init_val); i++)
+		if (nm256_ac97_init_val[i].reg == reg)
+			return i;
+	return -1;
+}
+
+/*
+ * some nm256 easily crash when reading from mixer registers
+ * thus we're treating it as a write-only mixer and cache the
+ * written values
+ */
+static unsigned short
+snd_nm256_ac97_read(struct snd_ac97 *ac97, unsigned short reg)
+{
+	struct nm256 *chip = ac97->private_data;
+	int idx = nm256_ac97_idx(reg);
+
+	if (idx < 0)
+		return 0;
+	return chip->ac97_regs[idx];
+}
+
+/* 
+ */
+static void
+snd_nm256_ac97_write(struct snd_ac97 *ac97,
+		     unsigned short reg, unsigned short val)
+{
+	struct nm256 *chip = ac97->private_data;
+	int tries = 2;
+	int idx = nm256_ac97_idx(reg);
+	u32 base;
+
+	if (idx < 0)
+		return;
+
+	base = chip->mixer_base;
+
+	snd_nm256_ac97_ready(chip);
+
+	/* Wait for the write to take, too. */
+	while (tries-- > 0) {
+		snd_nm256_writew(chip, base + reg, val);
+		msleep(1);  /* a little delay here seems better.. */
+		if (snd_nm256_ac97_ready(chip)) {
+			/* successful write: set cache */
+			chip->ac97_regs[idx] = val;
+			return;
+		}
+	}
+	dev_dbg(chip->card->dev, "nm256: ac97 codec not ready..\n");
+}
+
+/* static resolution table */
+static const struct snd_ac97_res_table nm256_res_table[] = {
+	{ AC97_MASTER, 0x1f1f },
+	{ AC97_HEADPHONE, 0x1f1f },
+	{ AC97_MASTER_MONO, 0x001f },
+	{ AC97_PC_BEEP, 0x001f },
+	{ AC97_PHONE, 0x001f },
+	{ AC97_MIC, 0x001f },
+	{ AC97_LINE, 0x1f1f },
+	{ AC97_CD, 0x1f1f },
+	{ AC97_VIDEO, 0x1f1f },
+	{ AC97_AUX, 0x1f1f },
+	{ AC97_PCM, 0x1f1f },
+	{ AC97_REC_GAIN, 0x0f0f },
+	{ } /* terminator */
+};
+
+/* initialize the ac97 into a known state */
+static void
+snd_nm256_ac97_reset(struct snd_ac97 *ac97)
+{
+	struct nm256 *chip = ac97->private_data;
+
+	/* Reset the mixer.  'Tis magic!  */
+	snd_nm256_writeb(chip, 0x6c0, 1);
+	if (! chip->reset_workaround) {
+		/* Dell latitude LS will lock up by this */
+		snd_nm256_writeb(chip, 0x6cc, 0x87);
+	}
+	if (! chip->reset_workaround_2) {
+		/* Dell latitude CSx will lock up by this */
+		snd_nm256_writeb(chip, 0x6cc, 0x80);
+		snd_nm256_writeb(chip, 0x6cc, 0x0);
+	}
+	if (! chip->in_resume) {
+		int i;
+		for (i = 0; i < ARRAY_SIZE(nm256_ac97_init_val); i++) {
+			/* preload the cache, so as to avoid even a single
+			 * read of the mixer regs
+			 */
+			snd_nm256_ac97_write(ac97, nm256_ac97_init_val[i].reg,
+					     nm256_ac97_init_val[i].value);
+		}
+	}
+}
+
+/* create an ac97 mixer interface */
+static int
+snd_nm256_mixer(struct nm256 *chip)
+{
+	struct snd_ac97_bus *pbus;
+	struct snd_ac97_template ac97;
+	int err;
+	static const struct snd_ac97_bus_ops ops = {
+		.reset = snd_nm256_ac97_reset,
+		.write = snd_nm256_ac97_write,
+		.read = snd_nm256_ac97_read,
+	};
+
+	chip->ac97_regs = devm_kcalloc(chip->card->dev,
+				       ARRAY_SIZE(nm256_ac97_init_val),
+				       sizeof(short), GFP_KERNEL);
+	if (! chip->ac97_regs)
+		return -ENOMEM;
+
+	err = snd_ac97_bus(chip->card, 0, &ops, NULL, &pbus);
+	if (err < 0)
+		return err;
+
+	memset(&ac97, 0, sizeof(ac97));
+	ac97.scaps = AC97_SCAP_AUDIO; /* we support audio! */
+	ac97.private_data = chip;
+	ac97.res_table = nm256_res_table;
+	pbus->no_vra = 1;
+	err = snd_ac97_mixer(pbus, &ac97, &chip->ac97);
+	if (err < 0)
+		return err;
+	if (! (chip->ac97->id & (0xf0000000))) {
+		/* looks like an invalid id */
+		sprintf(chip->card->mixername, "%s AC97", chip->card->driver);
+	}
+	return 0;
+}
+
+/* 
+ * See if the signature left by the NM256 BIOS is intact; if so, we use
+ * the associated address as the end of our audio buffer in the video
+ * RAM.
+ */
+
+static int
+snd_nm256_peek_for_sig(struct nm256 *chip)
+{
+	/* The signature is located 1K below the end of video RAM.  */
+	void __iomem *temp;
+	/* Default buffer end is 5120 bytes below the top of RAM.  */
+	unsigned long pointer_found = chip->buffer_end - 0x1400;
+	u32 sig;
+
+	temp = ioremap(chip->buffer_addr + chip->buffer_end - 0x400, 16);
+	if (temp == NULL) {
+		dev_err(chip->card->dev,
+			"Unable to scan for card signature in video RAM\n");
+		return -EBUSY;
+	}
+
+	sig = readl(temp);
+	if ((sig & NM_SIG_MASK) == NM_SIGNATURE) {
+		u32 pointer = readl(temp + 4);
+
+		/*
+		 * If it's obviously invalid, don't use it
+		 */
+		if (pointer == 0xffffffff ||
+		    pointer < chip->buffer_size ||
+		    pointer > chip->buffer_end) {
+			dev_err(chip->card->dev,
+				"invalid signature found: 0x%x\n", pointer);
+			iounmap(temp);
+			return -ENODEV;
+		} else {
+			pointer_found = pointer;
+			dev_info(chip->card->dev,
+				 "found card signature in video RAM: 0x%x\n",
+			       pointer);
+		}
+	}
+
+	iounmap(temp);
+	chip->buffer_end = pointer_found;
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+/*
+ * APM event handler, so the card is properly reinitialized after a power
+ * event.
+ */
+static int nm256_suspend(struct device *dev)
+{
+	struct snd_card *card = dev_get_drvdata(dev);
+	struct nm256 *chip = card->private_data;
+
+	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
+	snd_ac97_suspend(chip->ac97);
+	chip->coeffs_current = 0;
+	return 0;
+}
+
+static int nm256_resume(struct device *dev)
+{
+	struct snd_card *card = dev_get_drvdata(dev);
+	struct nm256 *chip = card->private_data;
+	int i;
+
+	/* Perform a full reset on the hardware */
+	chip->in_resume = 1;
+
+	snd_nm256_init_chip(chip);
+
+	/* restore ac97 */
+	snd_ac97_resume(chip->ac97);
+
+	for (i = 0; i < 2; i++) {
+		struct nm256_stream *s = &chip->streams[i];
+		if (s->substream && s->suspended) {
+			spin_lock_irq(&chip->reg_lock);
+			snd_nm256_set_format(chip, s, s->substream);
+			spin_unlock_irq(&chip->reg_lock);
+		}
+	}
+
+	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
+	chip->in_resume = 0;
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(nm256_pm, nm256_suspend, nm256_resume);
+#define NM256_PM_OPS	&nm256_pm
+#else
+#define NM256_PM_OPS	NULL
+#endif /* CONFIG_PM_SLEEP */
+
+static void snd_nm256_free(struct snd_card *card)
+{
+	struct nm256 *chip = card->private_data;
+
+	if (chip->streams[SNDRV_PCM_STREAM_PLAYBACK].running)
+		snd_nm256_playback_stop(chip);
+	if (chip->streams[SNDRV_PCM_STREAM_CAPTURE].running)
+		snd_nm256_capture_stop(chip);
+}
+
+static int
+snd_nm256_create(struct snd_card *card, struct pci_dev *pci)
+{
+	struct nm256 *chip = card->private_data;
+	int err, pval;
+	u32 addr;
+
+	err = pcim_enable_device(pci);
+	if (err < 0)
+		return err;
+
+	chip->card = card;
+	chip->pci = pci;
+	chip->use_cache = use_cache;
+	spin_lock_init(&chip->reg_lock);
+	chip->irq = -1;
+	mutex_init(&chip->irq_mutex);
+
+	/* store buffer sizes in bytes */
+	chip->streams[SNDRV_PCM_STREAM_PLAYBACK].bufsize = playback_bufsize * 1024;
+	chip->streams[SNDRV_PCM_STREAM_CAPTURE].bufsize = capture_bufsize * 1024;
+
+	/* 
+	 * The NM256 has two memory ports.  The first port is nothing
+	 * more than a chunk of video RAM, which is used as the I/O ring
+	 * buffer.  The second port has the actual juicy stuff (like the
+	 * mixer and the playback engine control registers).
+	 */
+
+	chip->buffer_addr = pci_resource_start(pci, 0);
+	chip->cport_addr = pci_resource_start(pci, 1);
+
+	err = pci_request_regions(pci, card->driver);
+	if (err < 0)
+		return err;
+
+	/* Init the memory port info.  */
+	/* remap control port (#2) */
+	chip->cport = devm_ioremap(&pci->dev, chip->cport_addr, NM_PORT2_SIZE);
+	if (!chip->cport) {
+		dev_err(card->dev, "unable to map control port %lx\n",
+			chip->cport_addr);
+		return -ENOMEM;
+	}
+
+	if (!strcmp(card->driver, "NM256AV")) {
+		/* Ok, try to see if this is a non-AC97 version of the hardware. */
+		pval = snd_nm256_readw(chip, NM_MIXER_PRESENCE);
+		if ((pval & NM_PRESENCE_MASK) != NM_PRESENCE_VALUE) {
+			if (! force_ac97) {
+				dev_err(card->dev,
+					"no ac97 is found!\n");
+				dev_err(card->dev,
+					"force the driver to load by passing in the module parameter\n");
+				dev_err(card->dev,
+					" force_ac97=1\n");
+				dev_err(card->dev,
+					"or try sb16, opl3sa2, or cs423x drivers instead.\n");
+				return -ENXIO;
+			}
+		}
+		chip->buffer_end = 2560 * 1024;
+		chip->interrupt = snd_nm256_interrupt;
+		chip->mixer_status_offset = NM_MIXER_STATUS_OFFSET;
+		chip->mixer_status_mask = NM_MIXER_READY_MASK;
+	} else {
+		/* Not sure if there is any relevant detect for the ZX or not.  */
+		if (snd_nm256_readb(chip, 0xa0b) != 0)
+			chip->buffer_end = 6144 * 1024;
+		else
+			chip->buffer_end = 4096 * 1024;
+
+		chip->interrupt = snd_nm256_interrupt_zx;
+		chip->mixer_status_offset = NM2_MIXER_STATUS_OFFSET;
+		chip->mixer_status_mask = NM2_MIXER_READY_MASK;
+	}
+	
+	chip->buffer_size = chip->streams[SNDRV_PCM_STREAM_PLAYBACK].bufsize +
+		chip->streams[SNDRV_PCM_STREAM_CAPTURE].bufsize;
+	if (chip->use_cache)
+		chip->buffer_size += NM_TOTAL_COEFF_COUNT * 4;
+	else
+		chip->buffer_size += NM_MAX_PLAYBACK_COEF_SIZE + NM_MAX_RECORD_COEF_SIZE;
+
+	if (buffer_top >= chip->buffer_size && buffer_top < chip->buffer_end)
+		chip->buffer_end = buffer_top;
+	else {
+		/* get buffer end pointer from signature */
+		err = snd_nm256_peek_for_sig(chip);
+		if (err < 0)
+			return err;
+	}
+
+	chip->buffer_start = chip->buffer_end - chip->buffer_size;
+	chip->buffer_addr += chip->buffer_start;
+
+	dev_info(card->dev, "Mapping port 1 from 0x%x - 0x%x\n",
+	       chip->buffer_start, chip->buffer_end);
+
+	chip->buffer = devm_ioremap(&pci->dev, chip->buffer_addr,
+				    chip->buffer_size);
+	if (!chip->buffer) {
+		dev_err(card->dev, "unable to map ring buffer at %lx\n",
+			chip->buffer_addr);
+		return -ENOMEM;
+	}
+
+	/* set offsets */
+	addr = chip->buffer_start;
+	chip->streams[SNDRV_PCM_STREAM_PLAYBACK].buf = addr;
+	addr += chip->streams[SNDRV_PCM_STREAM_PLAYBACK].bufsize;
+	chip->streams[SNDRV_PCM_STREAM_CAPTURE].buf = addr;
+	addr += chip->streams[SNDRV_PCM_STREAM_CAPTURE].bufsize;
+	if (chip->use_cache) {
+		chip->all_coeff_buf = addr;
+	} else {
+		chip->coeff_buf[SNDRV_PCM_STREAM_PLAYBACK] = addr;
+		addr += NM_MAX_PLAYBACK_COEF_SIZE;
+		chip->coeff_buf[SNDRV_PCM_STREAM_CAPTURE] = addr;
+	}
+
+	/* Fixed setting. */
+	chip->mixer_base = NM_MIXER_OFFSET;
+
+	chip->coeffs_current = 0;
+
+	snd_nm256_init_chip(chip);
+
+	// pci_set_master(pci); /* needed? */
+	return 0;
+}
+
+
+enum { NM_IGNORED, NM_RESET_WORKAROUND, NM_RESET_WORKAROUND_2 };
+
+static const struct snd_pci_quirk nm256_quirks[] = {
+	/* HP omnibook 4150 has cs4232 codec internally */
+	SND_PCI_QUIRK(0x103c, 0x0007, "HP omnibook 4150", NM_IGNORED),
+	/* Reset workarounds to avoid lock-ups */
+	SND_PCI_QUIRK(0x104d, 0x8041, "Sony PCG-F305", NM_RESET_WORKAROUND),
+	SND_PCI_QUIRK(0x1028, 0x0080, "Dell Latitude LS", NM_RESET_WORKAROUND),
+	SND_PCI_QUIRK(0x1028, 0x0091, "Dell Latitude CSx", NM_RESET_WORKAROUND_2),
+	{ } /* terminator */
+};
+
+
+static int snd_nm256_probe(struct pci_dev *pci,
+			   const struct pci_device_id *pci_id)
+{
+	struct snd_card *card;
+	struct nm256 *chip;
+	int err;
+	const struct snd_pci_quirk *q;
+
+	q = snd_pci_quirk_lookup(pci, nm256_quirks);
+	if (q) {
+		dev_dbg(&pci->dev, "Enabled quirk for %s.\n",
+			    snd_pci_quirk_name(q));
+		switch (q->value) {
+		case NM_IGNORED:
+			dev_info(&pci->dev,
+				 "The device is on the denylist. Loading stopped\n");
+			return -ENODEV;
+		case NM_RESET_WORKAROUND_2:
+			reset_workaround_2 = 1;
+			fallthrough;
+		case NM_RESET_WORKAROUND:
+			reset_workaround = 1;
+			break;
+		}
+	}
+
+	err = snd_devm_card_new(&pci->dev, index, id, THIS_MODULE,
+				sizeof(*chip), &card);
+	if (err < 0)
+		return err;
+	chip = card->private_data;
+
+	switch (pci->device) {
+	case PCI_DEVICE_ID_NEOMAGIC_NM256AV_AUDIO:
+		strcpy(card->driver, "NM256AV");
+		break;
+	case PCI_DEVICE_ID_NEOMAGIC_NM256ZX_AUDIO:
+		strcpy(card->driver, "NM256ZX");
+		break;
+	case PCI_DEVICE_ID_NEOMAGIC_NM256XL_PLUS_AUDIO:
+		strcpy(card->driver, "NM256XL+");
+		break;
+	default:
+		dev_err(&pci->dev, "invalid device id 0x%x\n", pci->device);
+		return -EINVAL;
+	}
+
+	if (vaio_hack)
+		buffer_top = 0x25a800;	/* this avoids conflicts with XFree86 server */
+
+	if (playback_bufsize < 4)
+		playback_bufsize = 4;
+	if (playback_bufsize > 128)
+		playback_bufsize = 128;
+	if (capture_bufsize < 4)
+		capture_bufsize = 4;
+	if (capture_bufsize > 128)
+		capture_bufsize = 128;
+	err = snd_nm256_create(card, pci);
+	if (err < 0)
+		return err;
+
+	if (reset_workaround) {
+		dev_dbg(&pci->dev, "reset_workaround activated\n");
+		chip->reset_workaround = 1;
+	}
+
+	if (reset_workaround_2) {
+		dev_dbg(&pci->dev, "reset_workaround_2 activated\n");
+		chip->reset_workaround_2 = 1;
+	}
+
+	err = snd_nm256_pcm(chip, 0);
+	if (err < 0)
+		return err;
+	err = snd_nm256_mixer(chip);
+	if (err < 0)
+		return err;
+
+	sprintf(card->shortname, "NeoMagic %s", card->driver);
+	sprintf(card->longname, "%s at 0x%lx & 0x%lx, irq %d",
+		card->shortname,
+		chip->buffer_addr, chip->cport_addr, chip->irq);
+
+	err = snd_card_register(card);
+	if (err < 0)
+		return err;
+	card->private_free = snd_nm256_free;
+
+	pci_set_drvdata(pci, card);
+	return 0;
+}
+
+static struct pci_driver nm256_driver = {
+	.name = KBUILD_MODNAME,
+	.id_table = snd_nm256_ids,
+	.probe = snd_nm256_probe,
+	.driver = {
+		.pm = NM256_PM_OPS,
+	},
+};
+
+module_pci_driver(nm256_driver);