hda_intel.c

/*
 *
 *  hda_intel.c - Implementation of primary alsa driver code base
 *                for Intel HD Audio.
 *
 *  Copyright(c) 2004 Intel Corporation. All rights reserved.
 *
 *  Copyright (c) 2004 Takashi Iwai <tiwai@suse.de>
 *                     PeiSen Hou <pshou@realtek.com.tw>
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License as published by the Free
 *  Software Foundation; either version 2 of the License, or (at your option)
 *  any later version.
 *
 *  This program is distributed in the hope that it will be useful, but WITHOUT
 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 *  more details.
 *
 *  You should have received a copy of the GNU General Public License along with
 *  this program; if not, write to the Free Software Foundation, Inc., 59
 *  Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 *  CONTACTS:
 *
 *  Matt Jared		matt.jared@intel.com
 *  Andy Kopp		andy.kopp@intel.com
 *  Dan Kogan		dan.d.kogan@intel.com
 *
 *  CHANGES:
 *
 *  2004.12.01	Major rewrite by tiwai, merged the work of pshou
 * 
 */

#include <asm/io.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/mutex.h>
#include <linux/reboot.h>
#include <sound/core.h>
#include <sound/initval.h>
#include "hda_codec.h"


static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;
static int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;
static char *model[SNDRV_CARDS];
static int position_fix[SNDRV_CARDS];
static int bdl_pos_adj[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] = -1};
static int probe_mask[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] = -1};
static int probe_only[SNDRV_CARDS];
static int single_cmd;
static int enable_msi;

module_param_array(index, int, NULL, 0444);
MODULE_PARM_DESC(index, "Index value for Intel HD audio interface.");
module_param_array(id, charp, NULL, 0444);
MODULE_PARM_DESC(id, "ID string for Intel HD audio interface.");
module_param_array(enable, bool, NULL, 0444);
MODULE_PARM_DESC(enable, "Enable Intel HD audio interface.");
module_param_array(model, charp, NULL, 0444);
MODULE_PARM_DESC(model, "Use the given board model.");
module_param_array(position_fix, int, NULL, 0444);
MODULE_PARM_DESC(position_fix, "Fix DMA pointer "
		 "(0 = auto, 1 = none, 2 = POSBUF).");
module_param_array(bdl_pos_adj, int, NULL, 0644);
MODULE_PARM_DESC(bdl_pos_adj, "BDL position adjustment offset.");
module_param_array(probe_mask, int, NULL, 0444);
MODULE_PARM_DESC(probe_mask, "Bitmask to probe codecs (default = -1).");
module_param_array(probe_only, bool, NULL, 0444);
MODULE_PARM_DESC(probe_only, "Only probing and no codec initialization.");
module_param(single_cmd, bool, 0444);
MODULE_PARM_DESC(single_cmd, "Use single command to communicate with codecs "
		 "(for debugging only).");
module_param(enable_msi, int, 0444);
MODULE_PARM_DESC(enable_msi, "Enable Message Signaled Interrupt (MSI)");

#ifdef CONFIG_SND_HDA_POWER_SAVE
static int power_save = CONFIG_SND_HDA_POWER_SAVE_DEFAULT;
module_param(power_save, int, 0644);
MODULE_PARM_DESC(power_save, "Automatic power-saving timeout "
		 "(in second, 0 = disable).");

/* reset the HD-audio controller in power save mode.
 * this may give more power-saving, but will take longer time to
 * wake up.
 */
static int power_save_controller = 1;
module_param(power_save_controller, bool, 0644);
MODULE_PARM_DESC(power_save_controller, "Reset controller in power save mode.");
#endif

MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{Intel, ICH6},"
			 "{Intel, ICH6M},"
			 "{Intel, ICH7},"
			 "{Intel, ESB2},"
			 "{Intel, ICH8},"
			 "{Intel, ICH9},"
			 "{Intel, ICH10},"
			 "{Intel, PCH},"
			 "{Intel, SCH},"
			 "{ATI, SB450},"
			 "{ATI, SB600},"
			 "{ATI, RS600},"
			 "{ATI, RS690},"
			 "{ATI, RS780},"
			 "{ATI, R600},"
			 "{ATI, RV630},"
			 "{ATI, RV610},"
			 "{ATI, RV670},"
			 "{ATI, RV635},"
			 "{ATI, RV620},"
			 "{ATI, RV770},"
			 "{VIA, VT8251},"
			 "{VIA, VT8237A},"
			 "{SiS, SIS966},"
			 "{ULI, M5461}}");
MODULE_DESCRIPTION("Intel HDA driver");

#ifdef CONFIG_SND_VERBOSE_PRINTK
#define SFX	/* nop */
#else
#define SFX	"hda-intel: "
#endif

/*
 * registers
 */
#define ICH6_REG_GCAP			0x00
#define   ICH6_GCAP_64OK	(1 << 0)   /* 64bit address support */
#define   ICH6_GCAP_NSDO	(3 << 1)   /* # of serial data out signals */
#define   ICH6_GCAP_BSS		(31 << 3)  /* # of bidirectional streams */
#define   ICH6_GCAP_ISS		(15 << 8)  /* # of input streams */
#define   ICH6_GCAP_OSS		(15 << 12) /* # of output streams */
#define ICH6_REG_VMIN			0x02
#define ICH6_REG_VMAJ			0x03
#define ICH6_REG_OUTPAY			0x04
#define ICH6_REG_INPAY			0x06
#define ICH6_REG_GCTL			0x08
#define   ICH6_GCTL_RESET	(1 << 0)   /* controller reset */
#define   ICH6_GCTL_FCNTRL	(1 << 1)   /* flush control */
#define   ICH6_GCTL_UNSOL	(1 << 8)   /* accept unsol. response enable */
#define ICH6_REG_WAKEEN			0x0c
#define ICH6_REG_STATESTS		0x0e
#define ICH6_REG_GSTS			0x10
#define   ICH6_GSTS_FSTS	(1 << 1)   /* flush status */
#define ICH6_REG_INTCTL			0x20
#define ICH6_REG_INTSTS			0x24
#define ICH6_REG_WALCLK			0x30
#define ICH6_REG_SYNC			0x34	
#define ICH6_REG_CORBLBASE		0x40
#define ICH6_REG_CORBUBASE		0x44
#define ICH6_REG_CORBWP			0x48
#define ICH6_REG_CORBRP			0x4a
#define   ICH6_CORBRP_RST	(1 << 15)  /* read pointer reset */
#define ICH6_REG_CORBCTL		0x4c
#define   ICH6_CORBCTL_RUN	(1 << 1)   /* enable DMA */
#define   ICH6_CORBCTL_CMEIE	(1 << 0)   /* enable memory error irq */
#define ICH6_REG_CORBSTS		0x4d
#define   ICH6_CORBSTS_CMEI	(1 << 0)   /* memory error indication */
#define ICH6_REG_CORBSIZE		0x4e

#define ICH6_REG_RIRBLBASE		0x50
#define ICH6_REG_RIRBUBASE		0x54
#define ICH6_REG_RIRBWP			0x58
#define   ICH6_RIRBWP_RST	(1 << 15)  /* write pointer reset */
#define ICH6_REG_RINTCNT		0x5a
#define ICH6_REG_RIRBCTL		0x5c
#define   ICH6_RBCTL_IRQ_EN	(1 << 0)   /* enable IRQ */
#define   ICH6_RBCTL_DMA_EN	(1 << 1)   /* enable DMA */
#define   ICH6_RBCTL_OVERRUN_EN	(1 << 2)   /* enable overrun irq */
#define ICH6_REG_RIRBSTS		0x5d
#define   ICH6_RBSTS_IRQ	(1 << 0)   /* response irq */
#define   ICH6_RBSTS_OVERRUN	(1 << 2)   /* overrun irq */
#define ICH6_REG_RIRBSIZE		0x5e

#define ICH6_REG_IC			0x60
#define ICH6_REG_IR			0x64
#define ICH6_REG_IRS			0x68
#define   ICH6_IRS_VALID	(1<<1)
#define   ICH6_IRS_BUSY		(1<<0)

#define ICH6_REG_DPLBASE		0x70
#define ICH6_REG_DPUBASE		0x74
#define   ICH6_DPLBASE_ENABLE	0x1	/* Enable position buffer */

/* SD offset: SDI0=0x80, SDI1=0xa0, ... SDO3=0x160 */
enum { SDI0, SDI1, SDI2, SDI3, SDO0, SDO1, SDO2, SDO3 };

/* stream register offsets from stream base */
#define ICH6_REG_SD_CTL			0x00
#define ICH6_REG_SD_STS			0x03
#define ICH6_REG_SD_LPIB		0x04
#define ICH6_REG_SD_CBL			0x08
#define ICH6_REG_SD_LVI			0x0c
#define ICH6_REG_SD_FIFOW		0x0e
#define ICH6_REG_SD_FIFOSIZE		0x10
#define ICH6_REG_SD_FORMAT		0x12
#define ICH6_REG_SD_BDLPL		0x18
#define ICH6_REG_SD_BDLPU		0x1c

/* PCI space */
#define ICH6_PCIREG_TCSEL	0x44

/*
 * other constants
 */

/* max number of SDs */
/* ICH, ATI and VIA have 4 playback and 4 capture */
#define ICH6_NUM_CAPTURE	4
#define ICH6_NUM_PLAYBACK	4

/* ULI has 6 playback and 5 capture */
#define ULI_NUM_CAPTURE		5
#define ULI_NUM_PLAYBACK	6

/* ATI HDMI has 1 playback and 0 capture */
#define ATIHDMI_NUM_CAPTURE	0
#define ATIHDMI_NUM_PLAYBACK	1

/* TERA has 4 playback and 3 capture */
#define TERA_NUM_CAPTURE	3
#define TERA_NUM_PLAYBACK	4

/* this number is statically defined for simplicity */
#define MAX_AZX_DEV		16

/* max number of fragments - we may use more if allocating more pages for BDL */
#define BDL_SIZE		4096
#define AZX_MAX_BDL_ENTRIES	(BDL_SIZE / 16)
#define AZX_MAX_FRAG		32
/* max buffer size - no h/w limit, you can increase as you like */
#define AZX_MAX_BUF_SIZE	(1024*1024*1024)
/* max number of PCM devics per card */
#define AZX_MAX_PCMS		8

/* RIRB int mask: overrun[2], response[0] */
#define RIRB_INT_RESPONSE	0x01
#define RIRB_INT_OVERRUN	0x04
#define RIRB_INT_MASK		0x05

/* STATESTS int mask: S3,SD2,SD1,SD0 */
#define AZX_MAX_CODECS		4
#define STATESTS_INT_MASK	((1 << AZX_MAX_CODECS) - 1)

/* SD_CTL bits */
#define SD_CTL_STREAM_RESET	0x01	/* stream reset bit */
#define SD_CTL_DMA_START	0x02	/* stream DMA start bit */
#define SD_CTL_STRIPE		(3 << 16)	/* stripe control */
#define SD_CTL_TRAFFIC_PRIO	(1 << 18)	/* traffic priority */
#define SD_CTL_DIR		(1 << 19)	/* bi-directional stream */
#define SD_CTL_STREAM_TAG_MASK	(0xf << 20)
#define SD_CTL_STREAM_TAG_SHIFT	20

/* SD_CTL and SD_STS */
#define SD_INT_DESC_ERR		0x10	/* descriptor error interrupt */
#define SD_INT_FIFO_ERR		0x08	/* FIFO error interrupt */
#define SD_INT_COMPLETE		0x04	/* completion interrupt */
#define SD_INT_MASK		(SD_INT_DESC_ERR|SD_INT_FIFO_ERR|\
				 SD_INT_COMPLETE)

/* SD_STS */
#define SD_STS_FIFO_READY	0x20	/* FIFO ready */

/* INTCTL and INTSTS */
#define ICH6_INT_ALL_STREAM	0xff	   /* all stream interrupts */
#define ICH6_INT_CTRL_EN	0x40000000 /* controller interrupt enable bit */
#define ICH6_INT_GLOBAL_EN	0x80000000 /* global interrupt enable bit */

/* below are so far hardcoded - should read registers in future */
#define ICH6_MAX_CORB_ENTRIES	256
#define ICH6_MAX_RIRB_ENTRIES	256

/* position fix mode */
enum {
	POS_FIX_AUTO,
	POS_FIX_LPIB,
	POS_FIX_POSBUF,
};

/* Defines for ATI HD Audio support in SB450 south bridge */
#define ATI_SB450_HDAUDIO_MISC_CNTR2_ADDR   0x42
#define ATI_SB450_HDAUDIO_ENABLE_SNOOP      0x02

/* Defines for Nvidia HDA support */
#define NVIDIA_HDA_TRANSREG_ADDR      0x4e
#define NVIDIA_HDA_ENABLE_COHBITS     0x0f
#define NVIDIA_HDA_ISTRM_COH          0x4d
#define NVIDIA_HDA_OSTRM_COH          0x4c
#define NVIDIA_HDA_ENABLE_COHBIT      0x01

/* Defines for Intel SCH HDA snoop control */
#define INTEL_SCH_HDA_DEVC      0x78
#define INTEL_SCH_HDA_DEVC_NOSNOOP       (0x1<<11)

/* Define IN stream 0 FIFO size offset in VIA controller */
#define VIA_IN_STREAM0_FIFO_SIZE_OFFSET	0x90
/* Define VIA HD Audio Device ID*/
#define VIA_HDAC_DEVICE_ID		0x3288

/* HD Audio class code */
#define PCI_CLASS_MULTIMEDIA_HD_AUDIO	0x0403

/*
 */

struct azx_dev {
	struct snd_dma_buffer bdl; /* BDL buffer */
	u32 *posbuf;		/* position buffer pointer */

	unsigned int bufsize;	/* size of the play buffer in bytes */
	unsigned int period_bytes; /* size of the period in bytes */
	unsigned int frags;	/* number for period in the play buffer */
	unsigned int fifo_size;	/* FIFO size */
	unsigned long start_jiffies;	/* start + minimum jiffies */
	unsigned long min_jiffies;	/* minimum jiffies before position is valid */

	void __iomem *sd_addr;	/* stream descriptor pointer */

	u32 sd_int_sta_mask;	/* stream int status mask */

	/* pcm support */
	struct snd_pcm_substream *substream;	/* assigned substream,
						 * set in PCM open
						 */
	unsigned int format_val;	/* format value to be set in the
					 * controller and the codec
					 */
	unsigned char stream_tag;	/* assigned stream */
	unsigned char index;		/* stream index */

	unsigned int opened :1;
	unsigned int running :1;
	unsigned int irq_pending :1;
	unsigned int start_flag: 1;	/* stream full start flag */
	/*
	 * For VIA:
	 *  A flag to ensure DMA position is 0
	 *  when link position is not greater than FIFO size
	 */
	unsigned int insufficient :1;
};

/* CORB/RIRB */
struct azx_rb {
	u32 *buf;		/* CORB/RIRB buffer
				 * Each CORB entry is 4byte, RIRB is 8byte
				 */
	dma_addr_t addr;	/* physical address of CORB/RIRB buffer */
	/* for RIRB */
	unsigned short rp, wp;	/* read/write pointers */
	int cmds[AZX_MAX_CODECS];	/* number of pending requests */
	u32 res[AZX_MAX_CODECS];	/* last read value */
};

struct azx {
	struct snd_card *card;
	struct pci_dev *pci;
	int dev_index;

	/* chip type specific */
	int driver_type;
	int playback_streams;
	int playback_index_offset;
	int capture_streams;
	int capture_index_offset;
	int num_streams;

	/* pci resources */
	unsigned long addr;
	void __iomem *remap_addr;
	int irq;

	/* locks */
	spinlock_t reg_lock;
	struct mutex open_mutex;

	/* streams (x num_streams) */
	struct azx_dev *azx_dev;

	/* PCM */
	struct snd_pcm *pcm[AZX_MAX_PCMS];

	/* HD codec */
	unsigned short codec_mask;
	int  codec_probe_mask; /* copied from probe_mask option */
	struct hda_bus *bus;

	/* CORB/RIRB */
	struct azx_rb corb;
	struct azx_rb rirb;

	/* CORB/RIRB and position buffers */
	struct snd_dma_buffer rb;
	struct snd_dma_buffer posbuf;

	/* flags */
	int position_fix;
	unsigned int running :1;
	unsigned int initialized :1;
	unsigned int single_cmd :1;
	unsigned int polling_mode :1;
	unsigned int msi :1;
	unsigned int irq_pending_warned :1;
	unsigned int via_dmapos_patch :1; /* enable DMA-position fix for VIA */
	unsigned int probing :1; /* codec probing phase */

	/* for debugging */
	unsigned int last_cmd;	/* last issued command (to sync) */

	/* for pending irqs */
	struct work_struct irq_pending_work;

	/* reboot notifier (for mysterious hangup problem at power-down) */
	struct notifier_block reboot_notifier;
};

/* driver types */
enum {
	AZX_DRIVER_ICH,
	AZX_DRIVER_SCH,
	AZX_DRIVER_ATI,
	AZX_DRIVER_ATIHDMI,
	AZX_DRIVER_VIA,
	AZX_DRIVER_SIS,
	AZX_DRIVER_ULI,
	AZX_DRIVER_NVIDIA,
	AZX_DRIVER_TERA,
	AZX_DRIVER_GENERIC,
	AZX_NUM_DRIVERS, /* keep this as last entry */
};

static char *driver_short_names[] __devinitdata = {
	[AZX_DRIVER_ICH] = "HDA Intel",
	[AZX_DRIVER_SCH] = "HDA Intel MID",
	[AZX_DRIVER_ATI] = "HDA ATI SB",
	[AZX_DRIVER_ATIHDMI] = "HDA ATI HDMI",
	[AZX_DRIVER_VIA] = "HDA VIA VT82xx",
	[AZX_DRIVER_SIS] = "HDA SIS966",
	[AZX_DRIVER_ULI] = "HDA ULI M5461",
	[AZX_DRIVER_NVIDIA] = "HDA NVidia",
	[AZX_DRIVER_TERA] = "HDA Teradici", 
	[AZX_DRIVER_GENERIC] = "HD-Audio Generic",
};

/*
 * macros for easy use
 */
#define azx_writel(chip,reg,value) \
	writel(value, (chip)->remap_addr + ICH6_REG_##reg)
#define azx_readl(chip,reg) \
	readl((chip)->remap_addr + ICH6_REG_##reg)
#define azx_writew(chip,reg,value) \
	writew(value, (chip)->remap_addr + ICH6_REG_##reg)
#define azx_readw(chip,reg) \
	readw((chip)->remap_addr + ICH6_REG_##reg)
#define azx_writeb(chip,reg,value) \
	writeb(value, (chip)->remap_addr + ICH6_REG_##reg)
#define azx_readb(chip,reg) \
	readb((chip)->remap_addr + ICH6_REG_##reg)

#define azx_sd_writel(dev,reg,value) \
	writel(value, (dev)->sd_addr + ICH6_REG_##reg)
#define azx_sd_readl(dev,reg) \
	readl((dev)->sd_addr + ICH6_REG_##reg)
#define azx_sd_writew(dev,reg,value) \
	writew(value, (dev)->sd_addr + ICH6_REG_##reg)
#define azx_sd_readw(dev,reg) \
	readw((dev)->sd_addr + ICH6_REG_##reg)
#define azx_sd_writeb(dev,reg,value) \
	writeb(value, (dev)->sd_addr + ICH6_REG_##reg)
#define azx_sd_readb(dev,reg) \
	readb((dev)->sd_addr + ICH6_REG_##reg)

/* for pcm support */
#define get_azx_dev(substream) (substream->runtime->private_data)

static int azx_acquire_irq(struct azx *chip, int do_disconnect);

/*
 * Interface for HD codec
 */

/*
 * CORB / RIRB interface
 */
static int azx_alloc_cmd_io(struct azx *chip)
{
	int err;

	/* single page (at least 4096 bytes) must suffice for both ringbuffes */
	err = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV,
				  snd_dma_pci_data(chip->pci),
				  PAGE_SIZE, &chip->rb);
	if (err < 0) {
		snd_printk(KERN_ERR SFX "cannot allocate CORB/RIRB\n");
		return err;
	}
	return 0;
}

static void azx_init_cmd_io(struct azx *chip)
{
	spin_lock_irq(&chip->reg_lock);
	/* CORB set up */
	chip->corb.addr = chip->rb.addr;
	chip->corb.buf = (u32 *)chip->rb.area;
	azx_writel(chip, CORBLBASE, (u32)chip->corb.addr);
	azx_writel(chip, CORBUBASE, upper_32_bits(chip->corb.addr));

	/* set the corb size to 256 entries (ULI requires explicitly) */
	azx_writeb(chip, CORBSIZE, 0x02);
	/* set the corb write pointer to 0 */
	azx_writew(chip, CORBWP, 0);
	/* reset the corb hw read pointer */
	azx_writew(chip, CORBRP, ICH6_CORBRP_RST);
	/* enable corb dma */
	azx_writeb(chip, CORBCTL, ICH6_CORBCTL_RUN);

	/* RIRB set up */
	chip->rirb.addr = chip->rb.addr + 2048;
	chip->rirb.buf = (u32 *)(chip->rb.area + 2048);
	chip->rirb.wp = chip->rirb.rp = 0;
	memset(chip->rirb.cmds, 0, sizeof(chip->rirb.cmds));
	azx_writel(chip, RIRBLBASE, (u32)chip->rirb.addr);
	azx_writel(chip, RIRBUBASE, upper_32_bits(chip->rirb.addr));

	/* set the rirb size to 256 entries (ULI requires explicitly) */
	azx_writeb(chip, RIRBSIZE, 0x02);
	/* reset the rirb hw write pointer */
	azx_writew(chip, RIRBWP, ICH6_RIRBWP_RST);
	/* set N=1, get RIRB response interrupt for new entry */
	azx_writew(chip, RINTCNT, 1);
	/* enable rirb dma and response irq */
	azx_writeb(chip, RIRBCTL, ICH6_RBCTL_DMA_EN | ICH6_RBCTL_IRQ_EN);
	spin_unlock_irq(&chip->reg_lock);
}

static void azx_free_cmd_io(struct azx *chip)
{
	spin_lock_irq(&chip->reg_lock);
	/* disable ringbuffer DMAs */
	azx_writeb(chip, RIRBCTL, 0);
	azx_writeb(chip, CORBCTL, 0);
	spin_unlock_irq(&chip->reg_lock);
}

static unsigned int azx_command_addr(u32 cmd)
{
	unsigned int addr = cmd >> 28;

	if (addr >= AZX_MAX_CODECS) {
		snd_BUG();
		addr = 0;
	}

	return addr;
}

static unsigned int azx_response_addr(u32 res)
{
	unsigned int addr = res & 0xf;

	if (addr >= AZX_MAX_CODECS) {
		snd_BUG();
		addr = 0;
	}

	return addr;
}

/* send a command */
static int azx_corb_send_cmd(struct hda_bus *bus, u32 val)
{
	struct azx *chip = bus->private_data;
	unsigned int addr = azx_command_addr(val);
	unsigned int wp;

	spin_lock_irq(&chip->reg_lock);

	/* add command to corb */
	wp = azx_readb(chip, CORBWP);
	wp++;
	wp %= ICH6_MAX_CORB_ENTRIES;

	chip->rirb.cmds[addr]++;
	chip->corb.buf[wp] = cpu_to_le32(val);
	azx_writel(chip, CORBWP, wp);

	spin_unlock_irq(&chip->reg_lock);

	return 0;
}

#define ICH6_RIRB_EX_UNSOL_EV	(1<<4)

/* retrieve RIRB entry - called from interrupt handler */
static void azx_update_rirb(struct azx *chip)
{
	unsigned int rp, wp;
	unsigned int addr;
	u32 res, res_ex;

	wp = azx_readb(chip, RIRBWP);
	if (wp == chip->rirb.wp)
		return;
	chip->rirb.wp = wp;

	while (chip->rirb.rp != wp) {
		chip->rirb.rp++;
		chip->rirb.rp %= ICH6_MAX_RIRB_ENTRIES;

		rp = chip->rirb.rp << 1; /* an RIRB entry is 8-bytes */
		res_ex = le32_to_cpu(chip->rirb.buf[rp + 1]);
		res = le32_to_cpu(chip->rirb.buf[rp]);
		addr = azx_response_addr(res_ex);
		if (res_ex & ICH6_RIRB_EX_UNSOL_EV)
			snd_hda_queue_unsol_event(chip->bus, res, res_ex);
		else if (chip->rirb.cmds[addr]) {
			chip->rirb.res[addr] = res;
			smp_wmb();
			chip->rirb.cmds[addr]--;
		}
	}
}

/* receive a response */
static unsigned int azx_rirb_get_response(struct hda_bus *bus,
					  unsigned int addr)
{
	struct azx *chip = bus->private_data;
	unsigned long timeout;

 again:
	timeout = jiffies + msecs_to_jiffies(1000);
	for (;;) {
		if (chip->polling_mode) {
			spin_lock_irq(&chip->reg_lock);
			azx_update_rirb(chip);
			spin_unlock_irq(&chip->reg_lock);
		}
		if (!chip->rirb.cmds[addr]) {
			smp_rmb();
			bus->rirb_error = 0;
			return chip->rirb.res[addr]; /* the last value */
		}
		if (time_after(jiffies, timeout))
			break;
		if (bus->needs_damn_long_delay)
			msleep(2); /* temporary workaround */
		else {
			udelay(10);
			cond_resched();
		}
	}

	if (chip->msi) {
		snd_printk(KERN_WARNING SFX "No response from codec, "
			   "disabling MSI: last cmd=0x%08x\n", chip->last_cmd);
		free_irq(chip->irq, chip);
		chip->irq = -1;
		pci_disable_msi(chip->pci);
		chip->msi = 0;
		if (azx_acquire_irq(chip, 1) < 0) {
			bus->rirb_error = 1;
			return -1;
		}
		goto again;
	}

	if (!chip->polling_mode) {
		snd_printk(KERN_WARNING SFX "azx_get_response timeout, "
			   "switching to polling mode: last cmd=0x%08x\n",
			   chip->last_cmd);
		chip->polling_mode = 1;
		goto again;
	}

	if (chip->probing) {
		/* If this critical timeout happens during the codec probing
		 * phase, this is likely an access to a non-existing codec
		 * slot.  Better to return an error and reset the system.
		 */
		return -1;
	}

	/* a fatal communication error; need either to reset or to fallback
	 * to the single_cmd mode
	 */
	bus->rirb_error = 1;
	if (bus->allow_bus_reset && !bus->response_reset && !bus->in_reset) {
		bus->response_reset = 1;
		return -1; /* give a chance to retry */
	}

	snd_printk(KERN_ERR "hda_intel: azx_get_response timeout, "
		   "switching to single_cmd mode: last cmd=0x%08x\n",
		   chip->last_cmd);
	chip->single_cmd = 1;
	bus->response_reset = 0;
	/* re-initialize CORB/RIRB */
	azx_free_cmd_io(chip);
	azx_init_cmd_io(chip);
	return -1;
}

/*
 * Use the single immediate command instead of CORB/RIRB for simplicity
 *
 * Note: according to Intel, this is not preferred use.  The command was
 *       intended for the BIOS only, and may get confused with unsolicited
 *       responses.  So, we shouldn't use it for normal operation from the
 *       driver.
 *       I left the codes, however, for debugging/testing purposes.
 */

/* receive a response */
static int azx_single_wait_for_response(struct azx *chip, unsigned int addr)
{
	int timeout = 50;

	while (timeout--) {
		/* check IRV busy bit */
		if (azx_readw(chip, IRS) & ICH6_IRS_VALID) {
			/* reuse rirb.res as the response return value */
			chip->rirb.res[addr] = azx_readl(chip, IR);
			return 0;
		}
		udelay(1);
	}
	if (printk_ratelimit())
		snd_printd(SFX "get_response timeout: IRS=0x%x\n",
			   azx_readw(chip, IRS));
	chip->rirb.res[addr] = -1;
	return -EIO;
}

/* send a command */
static int azx_single_send_cmd(struct hda_bus *bus, u32 val)
{
	struct azx *chip = bus->private_data;
	unsigned int addr = azx_command_addr(val);
	int timeout = 50;

	bus->rirb_error = 0;
	while (timeout--) {
		/* check ICB busy bit */
		if (!((azx_readw(chip, IRS) & ICH6_IRS_BUSY))) {
			/* Clear IRV valid bit */
			azx_writew(chip, IRS, azx_readw(chip, IRS) |
				   ICH6_IRS_VALID);
			azx_writel(chip, IC, val);
			azx_writew(chip, IRS, azx_readw(chip, IRS) |
				   ICH6_IRS_BUSY);
			return azx_single_wait_for_response(chip, addr);
		}
		udelay(1);
	}
	if (printk_ratelimit())
		snd_printd(SFX "send_cmd timeout: IRS=0x%x, val=0x%x\n",
			   azx_readw(chip, IRS), val);
	return -EIO;
}

/* receive a response */
static unsigned int azx_single_get_response(struct hda_bus *bus,
					    unsigned int addr)
{
	struct azx *chip = bus->private_data;
	return chip->rirb.res[addr];
}

/*
 * The below are the main callbacks from hda_codec.
 *
 * They are just the skeleton to call sub-callbacks according to the
 * current setting of chip->single_cmd.
 */

/* send a command */
static int azx_send_cmd(struct hda_bus *bus, unsigned int val)
{
	struct azx *chip = bus->private_data;

	chip->last_cmd = val;
	if (chip->single_cmd)
		return azx_single_send_cmd(bus, val);
	else
		return azx_corb_send_cmd(bus, val);
}

/* get a response */
static unsigned int azx_get_response(struct hda_bus *bus,
				     unsigned int addr)
{
	struct azx *chip = bus->private_data;
	if (chip->single_cmd)
		return azx_single_get_response(bus, addr);
	else
		return azx_rirb_get_response(bus, addr);
}

#ifdef CONFIG_SND_HDA_POWER_SAVE
static void azx_power_notify(struct hda_bus *bus);
#endif

/* reset codec link */
static int azx_reset(struct azx *chip)
{
	int count;

	/* clear STATESTS */
	azx_writeb(chip, STATESTS, STATESTS_INT_MASK);

	/* reset controller */
	azx_writel(chip, GCTL, azx_readl(chip, GCTL) & ~ICH6_GCTL_RESET);

	count = 50;
	while (azx_readb(chip, GCTL) && --count)
		msleep(1);

	/* delay for >= 100us for codec PLL to settle per spec
	 * Rev 0.9 section 5.5.1
	 */
	msleep(1);

	/* Bring controller out of reset */
	azx_writeb(chip, GCTL, azx_readb(chip, GCTL) | ICH6_GCTL_RESET);

	count = 50;
	while (!azx_readb(chip, GCTL) && --count)
		msleep(1);

	/* Brent Chartrand said to wait >= 540us for codecs to initialize */
	msleep(1);

	/* check to see if controller is ready */
	if (!azx_readb(chip, GCTL)) {
		snd_printd(SFX "azx_reset: controller not ready!\n");
		return -EBUSY;
	}

	/* Accept unsolicited responses */
	azx_writel(chip, GCTL, azx_readl(chip, GCTL) | ICH6_GCTL_UNSOL);

	/* detect codecs */
	if (!chip->codec_mask) {
		chip->codec_mask = azx_readw(chip, STATESTS);
		snd_printdd(SFX "codec_mask = 0x%x\n", chip->codec_mask);
	}

	return 0;
}


/*
 * Lowlevel interface
 */  

/* enable interrupts */
static void azx_int_enable(struct azx *chip)
{
	/* enable controller CIE and GIE */
	azx_writel(chip, INTCTL, azx_readl(chip, INTCTL) |
		   ICH6_INT_CTRL_EN | ICH6_INT_GLOBAL_EN);
}

/* disable interrupts */
static void azx_int_disable(struct azx *chip)
{
	int i;

	/* disable interrupts in stream descriptor */
	for (i = 0; i < chip->num_streams; i++) {
		struct azx_dev *azx_dev = &chip->azx_dev[i];
		azx_sd_writeb(azx_dev, SD_CTL,
			      azx_sd_readb(azx_dev, SD_CTL) & ~SD_INT_MASK);
	}

	/* disable SIE for all streams */
	azx_writeb(chip, INTCTL, 0);

	/* disable controller CIE and GIE */
	azx_writel(chip, INTCTL, azx_readl(chip, INTCTL) &
		   ~(ICH6_INT_CTRL_EN | ICH6_INT_GLOBAL_EN));
}

/* clear interrupts */
static void azx_int_clear(struct azx *chip)
{
	int i;

	/* clear stream status */
	for (i = 0; i < chip->num_streams; i++) {
		struct azx_dev *azx_dev = &chip->azx_dev[i];
		azx_sd_writeb(azx_dev, SD_STS, SD_INT_MASK);
	}

	/* clear STATESTS */
	azx_writeb(chip, STATESTS, STATESTS_INT_MASK);

	/* clear rirb status */
	azx_writeb(chip, RIRBSTS, RIRB_INT_MASK);

	/* clear int status */
	azx_writel(chip, INTSTS, ICH6_INT_CTRL_EN | ICH6_INT_ALL_STREAM);
}

/* start a stream */
static void azx_stream_start(struct azx *chip, struct azx_dev *azx_dev)
{
	/*
	 * Before stream start, initialize parameter
	 */
	azx_dev->insufficient = 1;

	/* enable SIE */
	azx_writeb(chip, INTCTL,
		   azx_readb(chip, INTCTL) | (1 << azx_dev->index));
	/* set DMA start and interrupt mask */
	azx_sd_writeb(azx_dev, SD_CTL, azx_sd_readb(azx_dev, SD_CTL) |
		      SD_CTL_DMA_START | SD_INT_MASK);
}

/* stop DMA */
static void azx_stream_clear(struct azx *chip, struct azx_dev *azx_dev)
{
	azx_sd_writeb(azx_dev, SD_CTL, azx_sd_readb(azx_dev, SD_CTL) &
		      ~(SD_CTL_DMA_START | SD_INT_MASK));
	azx_sd_writeb(azx_dev, SD_STS, SD_INT_MASK); /* to be sure */
}

/* stop a stream */
static void azx_stream_stop(struct azx *chip, struct azx_dev *azx_dev)
{
	azx_stream_clear(chip, azx_dev);
	/* disable SIE */
	azx_writeb(chip, INTCTL,
		   azx_readb(chip, INTCTL) & ~(1 << azx_dev->index));
}


/*
 * reset and start the controller registers
 */
static void azx_init_chip(struct azx *chip)
{
	if (chip->initialized)
		return;

	/* reset controller */
	azx_reset(chip);

	/* initialize interrupts */
	azx_int_clear(chip);
	azx_int_enable(chip);

	/* initialize the codec command I/O */
	azx_init_cmd_io(chip);

	/* program the position buffer */
	azx_writel(chip, DPLBASE, (u32)chip->posbuf.addr);
	azx_writel(chip, DPUBASE, upper_32_bits(chip->posbuf.addr));

	chip->initialized = 1;
}

/*
 * initialize the PCI registers
 */
/* update bits in a PCI register byte */
static void update_pci_byte(struct pci_dev *pci, unsigned int reg,
			    unsigned char mask, unsigned char val)
{
	unsigned char data;

	pci_read_config_byte(pci, reg, &data);
	data &= ~mask;
	data |= (val & mask);
	pci_write_config_byte(pci, reg, data);
}

static void azx_init_pci(struct azx *chip)
{
	unsigned short snoop;

	/* Clear bits 0-2 of PCI register TCSEL (at offset 0x44)
	 * TCSEL == Traffic Class Select Register, which sets PCI express QOS
	 * Ensuring these bits are 0 clears playback static on some HD Audio
	 * codecs
	 */
	update_pci_byte(chip->pci, ICH6_PCIREG_TCSEL, 0x07, 0);

	switch (chip->driver_type) {
	case AZX_DRIVER_ATI:
		/* For ATI SB450 azalia HD audio, we need to enable snoop */
		update_pci_byte(chip->pci,
				ATI_SB450_HDAUDIO_MISC_CNTR2_ADDR, 
				0x07, ATI_SB450_HDAUDIO_ENABLE_SNOOP);
		break;
	case AZX_DRIVER_NVIDIA:
		/* For NVIDIA HDA, enable snoop */
		update_pci_byte(chip->pci,
				NVIDIA_HDA_TRANSREG_ADDR,
				0x0f, NVIDIA_HDA_ENABLE_COHBITS);
		update_pci_byte(chip->pci,
				NVIDIA_HDA_ISTRM_COH,
				0x01, NVIDIA_HDA_ENABLE_COHBIT);
		update_pci_byte(chip->pci,
				NVIDIA_HDA_OSTRM_COH,
				0x01, NVIDIA_HDA_ENABLE_COHBIT);
		break;
	case AZX_DRIVER_SCH:
		pci_read_config_word(chip->pci, INTEL_SCH_HDA_DEVC, &snoop);
		if (snoop & INTEL_SCH_HDA_DEVC_NOSNOOP) {
			pci_write_config_word(chip->pci, INTEL_SCH_HDA_DEVC,
				snoop & (~INTEL_SCH_HDA_DEVC_NOSNOOP));
			pci_read_config_word(chip->pci,
				INTEL_SCH_HDA_DEVC, &snoop);
			snd_printdd(SFX "HDA snoop disabled, enabling ... %s\n",
				(snoop & INTEL_SCH_HDA_DEVC_NOSNOOP)
				? "Failed" : "OK");
		}
		break;

        }
}


static int azx_position_ok(struct azx *chip, struct azx_dev *azx_dev);

/*
 * interrupt handler
 */
static irqreturn_t azx_interrupt(int irq, void *dev_id)
{
	struct azx *chip = dev_id;
	struct azx_dev *azx_dev;
	u32 status;
	int i, ok;

	spin_lock(&chip->reg_lock);

	status = azx_readl(chip, INTSTS);
	if (status == 0) {
		spin_unlock(&chip->reg_lock);
		return IRQ_NONE;
	}
	
	for (i = 0; i < chip->num_streams; i++) {
		azx_dev = &chip->azx_dev[i];
		if (status & azx_dev->sd_int_sta_mask) {
			azx_sd_writeb(azx_dev, SD_STS, SD_INT_MASK);
			if (!azx_dev->substream || !azx_dev->running)
				continue;
			/* check whether this IRQ is really acceptable */
			ok = azx_position_ok(chip, azx_dev);
			if (ok == 1) {
				azx_dev->irq_pending = 0;
				spin_unlock(&chip->reg_lock);
				snd_pcm_period_elapsed(azx_dev->substream);
				spin_lock(&chip->reg_lock);
			} else if (ok == 0 && chip->bus && chip->bus->workq) {
				/* bogus IRQ, process it later */
				azx_dev->irq_pending = 1;
				queue_work(chip->bus->workq,
					   &chip->irq_pending_work);
			}
		}
	}

	/* clear rirb int */
	status = azx_readb(chip, RIRBSTS);
	if (status & RIRB_INT_MASK) {
		if (status & RIRB_INT_RESPONSE)
			azx_update_rirb(chip);
		azx_writeb(chip, RIRBSTS, RIRB_INT_MASK);
	}

#if 0
	/* clear state status int */
	if (azx_readb(chip, STATESTS) & 0x04)
		azx_writeb(chip, STATESTS, 0x04);
#endif
	spin_unlock(&chip->reg_lock);
	
	return IRQ_HANDLED;
}


/*
 * set up a BDL entry
 */
static int setup_bdle(struct snd_pcm_substream *substream,
		      struct azx_dev *azx_dev, u32 **bdlp,
		      int ofs, int size, int with_ioc)
{
	u32 *bdl = *bdlp;

	while (size > 0) {
		dma_addr_t addr;
		int chunk;

		if (azx_dev->frags >= AZX_MAX_BDL_ENTRIES)
			return -EINVAL;

		addr = snd_pcm_sgbuf_get_addr(substream, ofs);
		/* program the address field of the BDL entry */
		bdl[0] = cpu_to_le32((u32)addr);
		bdl[1] = cpu_to_le32(upper_32_bits(addr));
		/* program the size field of the BDL entry */
		chunk = snd_pcm_sgbuf_get_chunk_size(substream, ofs, size);
		bdl[2] = cpu_to_le32(chunk);
		/* program the IOC to enable interrupt
		 * only when the whole fragment is processed
		 */
		size -= chunk;
		bdl[3] = (size || !with_ioc) ? 0 : cpu_to_le32(0x01);
		bdl += 4;
		azx_dev->frags++;
		ofs += chunk;
	}
	*bdlp = bdl;
	return ofs;
}

/*
 * set up BDL entries
 */
static int azx_setup_periods(struct azx *chip,
			     struct snd_pcm_substream *substream,
			     struct azx_dev *azx_dev)
{