/*
 *  Driver for Cirrus Logic CS4281 based PCI soundcard
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>,
 *
 *
 *   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
 *
 */

#include <asm/io.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/gameport.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/control.h>
#include <sound/pcm.h>
#include <sound/rawmidi.h>
#include <sound/ac97_codec.h>
#include <sound/tlv.h>
#include <sound/opl3.h>
#include <sound/initval.h>


MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
MODULE_DESCRIPTION("Cirrus Logic CS4281");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{Cirrus Logic,CS4281}}");

static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;      /* Index 0-MAX */
static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;       /* ID for this card */
static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;     /* Enable switches */
static bool dual_codec[SNDRV_CARDS];    /* dual codec */

module_param_array(index, int, NULL, 0444);
MODULE_PARM_DESC(index, "Index value for CS4281 soundcard.");
module_param_array(id, charp, NULL, 0444);
MODULE_PARM_DESC(id, "ID string for CS4281 soundcard.");
module_param_array(enable, bool, NULL, 0444);
MODULE_PARM_DESC(enable, "Enable CS4281 soundcard.");
module_param_array(dual_codec, bool, NULL, 0444);
MODULE_PARM_DESC(dual_codec, "Secondary Codec ID (0 = disabled).");

/*
 *  Direct registers
 */

#define CS4281_BA0_SIZE         0x1000
#define CS4281_BA1_SIZE         0x10000

/*
 *  BA0 registers
 */
#define BA0_HISR                0x0000  /* Host Interrupt Status Register */
#define BA0_HISR_INTENA         (1<<31) /* Internal Interrupt Enable Bit */
#define BA0_HISR_MIDI           (1<<22) /* MIDI port interrupt */
#define BA0_HISR_FIFOI          (1<<20) /* FIFO polled interrupt */
#define BA0_HISR_DMAI           (1<<18) /* DMA interrupt (half or end) */
#define BA0_HISR_FIFO(c)        (1<<(12+(c))) /* FIFO channel interrupt */
#define BA0_HISR_DMA(c)         (1<<(8+(c)))  /* DMA channel interrupt */
#define BA0_HISR_GPPI           (1<<5)  /* General Purpose Input (Primary chip) */
#define BA0_HISR_GPSI           (1<<4)  /* General Purpose Input (Secondary chip) */
#define BA0_HISR_GP3I           (1<<3)  /* GPIO3 pin Interrupt */
#define BA0_HISR_GP1I           (1<<2)  /* GPIO1 pin Interrupt */
#define BA0_HISR_VUPI           (1<<1)  /* VOLUP pin Interrupt */
#define BA0_HISR_VDNI           (1<<0)  /* VOLDN pin Interrupt */

#define BA0_HICR                0x0008  /* Host Interrupt Control Register */
#define BA0_HICR_CHGM           (1<<1)  /* INTENA Change Mask */
#define BA0_HICR_IEV            (1<<0)  /* INTENA Value */
#define BA0_HICR_EOI            (3<<0)  /* End of Interrupt command */

#define BA0_HIMR                0x000c  /* Host Interrupt Mask Register */
                                        /* Use same contants as for BA0_HISR */

#define BA0_IIER                0x0010  /* ISA Interrupt Enable Register */

#define BA0_HDSR0               0x00f0  /* Host DMA Engine 0 Status Register */
#define BA0_HDSR1               0x00f4  /* Host DMA Engine 1 Status Register */
#define BA0_HDSR2               0x00f8  /* Host DMA Engine 2 Status Register */
#define BA0_HDSR3               0x00fc  /* Host DMA Engine 3 Status Register */

#define BA0_HDSR_CH1P           (1<<25) /* Channel 1 Pending */
#define BA0_HDSR_CH2P           (1<<24) /* Channel 2 Pending */
#define BA0_HDSR_DHTC           (1<<17) /* DMA Half Terminal Count */
#define BA0_HDSR_DTC            (1<<16) /* DMA Terminal Count */
#define BA0_HDSR_DRUN           (1<<15) /* DMA Running */
#define BA0_HDSR_RQ             (1<<7)  /* Pending Request */

#define BA0_DCA0                0x0110  /* Host DMA Engine 0 Current Address */
#define BA0_DCC0                0x0114  /* Host DMA Engine 0 Current Count */
#define BA0_DBA0                0x0118  /* Host DMA Engine 0 Base Address */
#define BA0_DBC0                0x011c  /* Host DMA Engine 0 Base Count */
#define BA0_DCA1                0x0120  /* Host DMA Engine 1 Current Address */
#define BA0_DCC1                0x0124  /* Host DMA Engine 1 Current Count */
#define BA0_DBA1                0x0128  /* Host DMA Engine 1 Base Address */
#define BA0_DBC1                0x012c  /* Host DMA Engine 1 Base Count */
#define BA0_DCA2                0x0130  /* Host DMA Engine 2 Current Address */
#define BA0_DCC2                0x0134  /* Host DMA Engine 2 Current Count */
#define BA0_DBA2                0x0138  /* Host DMA Engine 2 Base Address */
#define BA0_DBC2                0x013c  /* Host DMA Engine 2 Base Count */
#define BA0_DCA3                0x0140  /* Host DMA Engine 3 Current Address */
#define BA0_DCC3                0x0144  /* Host DMA Engine 3 Current Count */
#define BA0_DBA3                0x0148  /* Host DMA Engine 3 Base Address */
#define BA0_DBC3                0x014c  /* Host DMA Engine 3 Base Count */
#define BA0_DMR0                0x0150  /* Host DMA Engine 0 Mode */
#define BA0_DCR0                0x0154  /* Host DMA Engine 0 Command */
#define BA0_DMR1                0x0158  /* Host DMA Engine 1 Mode */
#define BA0_DCR1                0x015c  /* Host DMA Engine 1 Command */
#define BA0_DMR2                0x0160  /* Host DMA Engine 2 Mode */
#define BA0_DCR2                0x0164  /* Host DMA Engine 2 Command */
#define BA0_DMR3                0x0168  /* Host DMA Engine 3 Mode */
#define BA0_DCR3                0x016c  /* Host DMA Engine 3 Command */

#define BA0_DMR_DMA             (1<<29) /* Enable DMA mode */
#define BA0_DMR_POLL            (1<<28) /* Enable poll mode */
#define BA0_DMR_TBC             (1<<25) /* Transfer By Channel */
#define BA0_DMR_CBC             (1<<24) /* Count By Channel (0 = frame resolution) */
#define BA0_DMR_SWAPC           (1<<22) /* Swap Left/Right Channels */
#define BA0_DMR_SIZE20          (1<<20) /* Sample is 20-bit */
#define BA0_DMR_USIGN           (1<<19) /* Unsigned */
#define BA0_DMR_BEND            (1<<18) /* Big Endian */
#define BA0_DMR_MONO            (1<<17) /* Mono */
#define BA0_DMR_SIZE8           (1<<16) /* Sample is 8-bit */
#define BA0_DMR_TYPE_DEMAND     (0<<6)
#define BA0_DMR_TYPE_SINGLE     (1<<6)
#define BA0_DMR_TYPE_BLOCK      (2<<6)
#define BA0_DMR_TYPE_CASCADE    (3<<6)  /* Not supported */
#define BA0_DMR_DEC             (1<<5)  /* Access Increment (0) or Decrement (1) */
#define BA0_DMR_AUTO            (1<<4)  /* Auto-Initialize */
#define BA0_DMR_TR_VERIFY       (0<<2)  /* Verify Transfer */
#define BA0_DMR_TR_WRITE        (1<<2)  /* Write Transfer */
#define BA0_DMR_TR_READ         (2<<2)  /* Read Transfer */

#define BA0_DCR_HTCIE           (1<<17) /* Half Terminal Count Interrupt */
#define BA0_DCR_TCIE            (1<<16) /* Terminal Count Interrupt */
#define BA0_DCR_MSK             (1<<0)  /* DMA Mask bit */

#define BA0_FCR0                0x0180  /* FIFO Control 0 */
#define BA0_FCR1                0x0184  /* FIFO Control 1 */
#define BA0_FCR2                0x0188  /* FIFO Control 2 */
#define BA0_FCR3                0x018c  /* FIFO Control 3 */

#define BA0_FCR_FEN             (1<<31) /* FIFO Enable bit */
#define BA0_FCR_DACZ            (1<<30) /* DAC Zero */
#define BA0_FCR_PSH             (1<<29) /* Previous Sample Hold */
#define BA0_FCR_RS(x)           (((x)&0x1f)<<24) /* Right Slot Mapping */
#define BA0_FCR_LS(x)           (((x)&0x1f)<<16) /* Left Slot Mapping */
#define BA0_FCR_SZ(x)           (((x)&0x7f)<<8) /* FIFO buffer size (in samples) */
#define BA0_FCR_OF(x)           (((x)&0x7f)<<0) /* FIFO starting offset (in samples) */

#define BA0_FPDR0               0x0190  /* FIFO Polled Data 0 */
#define BA0_FPDR1               0x0194  /* FIFO Polled Data 1 */
#define BA0_FPDR2               0x0198  /* FIFO Polled Data 2 */
#define BA0_FPDR3               0x019c  /* FIFO Polled Data 3 */

#define BA0_FCHS                0x020c  /* FIFO Channel Status */
#define BA0_FCHS_RCO(x)         (1<<(7+(((x)&3)<<3))) /* Right Channel Out */
#define BA0_FCHS_LCO(x)         (1<<(6+(((x)&3)<<3))) /* Left Channel Out */
#define BA0_FCHS_MRP(x)         (1<<(5+(((x)&3)<<3))) /* Move Read Pointer */
#define BA0_FCHS_FE(x)          (1<<(4+(((x)&3)<<3))) /* FIFO Empty */
#define BA0_FCHS_FF(x)          (1<<(3+(((x)&3)<<3))) /* FIFO Full */
#define BA0_FCHS_IOR(x)         (1<<(2+(((x)&3)<<3))) /* Internal Overrun Flag */
#define BA0_FCHS_RCI(x)         (1<<(1+(((x)&3)<<3))) /* Right Channel In */
#define BA0_FCHS_LCI(x)         (1<<(0+(((x)&3)<<3))) /* Left Channel In */

#define BA0_FSIC0               0x0210  /* FIFO Status and Interrupt Control 0 */
#define BA0_FSIC1               0x0214  /* FIFO Status and Interrupt Control 1 */
#define BA0_FSIC2               0x0218  /* FIFO Status and Interrupt Control 2 */
#define BA0_FSIC3               0x021c  /* FIFO Status and Interrupt Control 3 */

#define BA0_FSIC_FIC(x)         (((x)&0x7f)<<24) /* FIFO Interrupt Count */
#define BA0_FSIC_FORIE          (1<<23) /* FIFO OverRun Interrupt Enable */
#define BA0_FSIC_FURIE          (1<<22) /* FIFO UnderRun Interrupt Enable */
#define BA0_FSIC_FSCIE          (1<<16) /* FIFO Sample Count Interrupt Enable */
#define BA0_FSIC_FSC(x)         (((x)&0x7f)<<8) /* FIFO Sample Count */
#define BA0_FSIC_FOR            (1<<7)  /* FIFO OverRun */
#define BA0_FSIC_FUR            (1<<6)  /* FIFO UnderRun */
#define BA0_FSIC_FSCR           (1<<0)  /* FIFO Sample Count Reached */

#define BA0_PMCS                0x0344  /* Power Management Control/Status */
#define BA0_CWPR                0x03e0  /* Configuration Write Protect */

#define BA0_EPPMC               0x03e4  /* Extended PCI Power Management Control */
#define BA0_EPPMC_FPDN          (1<<14) /* Full Power DowN */

#define BA0_GPIOR               0x03e8  /* GPIO Pin Interface Register */

#define BA0_SPMC                0x03ec  /* Serial Port Power Management Control (& ASDIN2 enable) */
#define BA0_SPMC_GIPPEN         (1<<15) /* GP INT Primary PME# Enable */
#define BA0_SPMC_GISPEN         (1<<14) /* GP INT Secondary PME# Enable */
#define BA0_SPMC_EESPD          (1<<9)  /* EEPROM Serial Port Disable */
#define BA0_SPMC_ASDI2E         (1<<8)  /* ASDIN2 Enable */
#define BA0_SPMC_ASDO           (1<<7)  /* Asynchronous ASDOUT Assertion */
#define BA0_SPMC_WUP2           (1<<3)  /* Wakeup for Secondary Input */
#define BA0_SPMC_WUP1           (1<<2)  /* Wakeup for Primary Input */
#define BA0_SPMC_ASYNC          (1<<1)  /* Asynchronous ASYNC Assertion */
#define BA0_SPMC_RSTN           (1<<0)  /* Reset Not! */

#define BA0_CFLR                0x03f0  /* Configuration Load Register (EEPROM or BIOS) */
#define BA0_CFLR_DEFAULT        0x00000001 /* CFLR must be in AC97 link mode */
#define BA0_IISR                0x03f4  /* ISA Interrupt Select */
#define BA0_TMS                 0x03f8  /* Test Register */
#define BA0_SSVID               0x03fc  /* Subsystem ID register */

#define BA0_CLKCR1              0x0400  /* Clock Control Register 1 */
#define BA0_CLKCR1_CLKON        (1<<25) /* Read Only */
#define BA0_CLKCR1_DLLRDY       (1<<24) /* DLL Ready */
#define BA0_CLKCR1_DLLOS        (1<<6)  /* DLL Output Select */
#define BA0_CLKCR1_SWCE         (1<<5)  /* Clock Enable */
#define BA0_CLKCR1_DLLP         (1<<4)  /* DLL PowerUp */
#define BA0_CLKCR1_DLLSS        (((x)&3)<<3) /* DLL Source Select */

#define BA0_FRR                 0x0410  /* Feature Reporting Register */
#define BA0_SLT12O              0x041c  /* Slot 12 GPIO Output Register for AC-Link */

#define BA0_SERMC               0x0420  /* Serial Port Master Control */
#define BA0_SERMC_FCRN          (1<<27) /* Force Codec Ready Not */
#define BA0_SERMC_ODSEN2        (1<<25) /* On-Demand Support Enable ASDIN2 */
#define BA0_SERMC_ODSEN1        (1<<24) /* On-Demand Support Enable ASDIN1 */
#define BA0_SERMC_SXLB          (1<<21) /* ASDIN2 to ASDOUT Loopback */
#define BA0_SERMC_SLB           (1<<20) /* ASDOUT to ASDIN2 Loopback */
#define BA0_SERMC_LOVF          (1<<19) /* Loopback Output Valid Frame bit */
#define BA0_SERMC_TCID(x)       (((x)&3)<<16) /* Target Secondary Codec ID */
#define BA0_SERMC_PXLB          (5<<1)  /* Primary Port External Loopback */
#define BA0_SERMC_PLB           (4<<1)  /* Primary Port Internal Loopback */
#define BA0_SERMC_PTC           (7<<1)  /* Port Timing Configuration */
#define BA0_SERMC_PTC_AC97      (1<<1)  /* AC97 mode */
#define BA0_SERMC_MSPE          (1<<0)  /* Master Serial Port Enable */

#define BA0_SERC1               0x0428  /* Serial Port Configuration 1 */
#define BA0_SERC1_SO1F(x)       (((x)&7)>>1) /* Primary Output Port Format */
#define BA0_SERC1_AC97          (1<<1)
#define BA0_SERC1_SO1EN         (1<<0)  /* Primary Output Port Enable */

#define BA0_SERC2               0x042c  /* Serial Port Configuration 2 */
#define BA0_SERC2_SI1F(x)       (((x)&7)>>1) /* Primary Input Port Format */
#define BA0_SERC2_AC97          (1<<1)
#define BA0_SERC2_SI1EN         (1<<0)  /* Primary Input Port Enable */

#define BA0_SLT12M              0x045c  /* Slot 12 Monitor Register for Primary AC-Link */

#define BA0_ACCTL               0x0460  /* AC'97 Control */
#define BA0_ACCTL_TC            (1<<6)  /* Target Codec */
#define BA0_ACCTL_CRW           (1<<4)  /* 0=Write, 1=Read Command */
#define BA0_ACCTL_DCV           (1<<3)  /* Dynamic Command Valid */
#define BA0_ACCTL_VFRM          (1<<2)  /* Valid Frame */
#define BA0_ACCTL_ESYN          (1<<1)  /* Enable Sync */

#define BA0_ACSTS               0x0464  /* AC'97 Status */
#define BA0_ACSTS_VSTS          (1<<1)  /* Valid Status */
#define BA0_ACSTS_CRDY          (1<<0)  /* Codec Ready */

#define BA0_ACOSV               0x0468  /* AC'97 Output Slot Valid */
#define BA0_ACOSV_SLV(x)        (1<<((x)-3))

#define BA0_ACCAD               0x046c  /* AC'97 Command Address */
#define BA0_ACCDA               0x0470  /* AC'97 Command Data */

#define BA0_ACISV               0x0474  /* AC'97 Input Slot Valid */
#define BA0_ACISV_SLV(x)        (1<<((x)-3))

#define BA0_ACSAD               0x0478  /* AC'97 Status Address */
#define BA0_ACSDA               0x047c  /* AC'97 Status Data */
#define BA0_JSPT                0x0480  /* Joystick poll/trigger */
#define BA0_JSCTL               0x0484  /* Joystick control */
#define BA0_JSC1                0x0488  /* Joystick control */
#define BA0_JSC2                0x048c  /* Joystick control */
#define BA0_JSIO                0x04a0

#define BA0_MIDCR               0x0490  /* MIDI Control */
#define BA0_MIDCR_MRST          (1<<5)  /* Reset MIDI Interface */
#define BA0_MIDCR_MLB           (1<<4)  /* MIDI Loop Back Enable */
#define BA0_MIDCR_TIE           (1<<3)  /* MIDI Transmuit Interrupt Enable */
#define BA0_MIDCR_RIE           (1<<2)  /* MIDI Receive Interrupt Enable */
#define BA0_MIDCR_RXE           (1<<1)  /* MIDI Receive Enable */
#define BA0_MIDCR_TXE           (1<<0)  /* MIDI Transmit Enable */

#define BA0_MIDCMD              0x0494  /* MIDI Command (wo) */

#define BA0_MIDSR               0x0494  /* MIDI Status (ro) */
#define BA0_MIDSR_RDA           (1<<15) /* Sticky bit (RBE 1->0) */
#define BA0_MIDSR_TBE           (1<<14) /* Sticky bit (TBF 0->1) */
#define BA0_MIDSR_RBE           (1<<7)  /* Receive Buffer Empty */
#define BA0_MIDSR_TBF           (1<<6)  /* Transmit Buffer Full */

#define BA0_MIDWP               0x0498  /* MIDI Write */
#define BA0_MIDRP               0x049c  /* MIDI Read (ro) */

#define BA0_AODSD1              0x04a8  /* AC'97 On-Demand Slot Disable for primary link (ro) */
#define BA0_AODSD1_NDS(x)       (1<<((x)-3))

#define BA0_AODSD2              0x04ac  /* AC'97 On-Demand Slot Disable for secondary link (ro) */
#define BA0_AODSD2_NDS(x)       (1<<((x)-3))

#define BA0_CFGI                0x04b0  /* Configure Interface (EEPROM interface) */
#define BA0_SLT12M2             0x04dc  /* Slot 12 Monitor Register 2 for secondary AC-link */
#define BA0_ACSTS2              0x04e4  /* AC'97 Status Register 2 */
#define BA0_ACISV2              0x04f4  /* AC'97 Input Slot Valid Register 2 */
#define BA0_ACSAD2              0x04f8  /* AC'97 Status Address Register 2 */
#define BA0_ACSDA2              0x04fc  /* AC'97 Status Data Register 2 */
#define BA0_FMSR                0x0730  /* FM Synthesis Status (ro) */
#define BA0_B0AP                0x0730  /* FM Bank 0 Address Port (wo) */
#define BA0_FMDP                0x0734  /* FM Data Port */
#define BA0_B1AP                0x0738  /* FM Bank 1 Address Port */
#define BA0_B1DP                0x073c  /* FM Bank 1 Data Port */

#define BA0_SSPM                0x0740  /* Sound System Power Management */
#define BA0_SSPM_MIXEN          (1<<6)  /* Playback SRC + FM/Wavetable MIX */
#define BA0_SSPM_CSRCEN         (1<<5)  /* Capture Sample Rate Converter Enable */
#define BA0_SSPM_PSRCEN         (1<<4)  /* Playback Sample Rate Converter Enable */
#define BA0_SSPM_JSEN           (1<<3)  /* Joystick Enable */
#define BA0_SSPM_ACLEN          (1<<2)  /* Serial Port Engine and AC-Link Enable */
#define BA0_SSPM_FMEN           (1<<1)  /* FM Synthesis Block Enable */

#define BA0_DACSR               0x0744  /* DAC Sample Rate - Playback SRC */
#define BA0_ADCSR               0x0748  /* ADC Sample Rate - Capture SRC */

#define BA0_SSCR                0x074c  /* Sound System Control Register */
#define BA0_SSCR_HVS1           (1<<23) /* Hardwave Volume Step (0=1,1=2) */
#define BA0_SSCR_MVCS           (1<<19) /* Master Volume Codec Select */
#define BA0_SSCR_MVLD           (1<<18) /* Master Volume Line Out Disable */
#define BA0_SSCR_MVAD           (1<<17) /* Master Volume Alternate Out Disable */
#define BA0_SSCR_MVMD           (1<<16) /* Master Volume Mono Out Disable */
#define BA0_SSCR_XLPSRC         (1<<8)  /* External SRC Loopback Mode */
#define BA0_SSCR_LPSRC          (1<<7)  /* SRC Loopback Mode */
#define BA0_SSCR_CDTX           (1<<5)  /* CD Transfer Data */
#define BA0_SSCR_HVC            (1<<3)  /* Harware Volume Control Enable */

#define BA0_FMLVC               0x0754  /* FM Synthesis Left Volume Control */
#define BA0_FMRVC               0x0758  /* FM Synthesis Right Volume Control */
#define BA0_SRCSA               0x075c  /* SRC Slot Assignments */
#define BA0_PPLVC               0x0760  /* PCM Playback Left Volume Control */
#define BA0_PPRVC               0x0764  /* PCM Playback Right Volume Control */
#define BA0_PASR                0x0768  /* playback sample rate */
#define BA0_CASR                0x076C  /* capture sample rate */

/* Source Slot Numbers - Playback */
#define SRCSLOT_LEFT_PCM_PLAYBACK               0
#define SRCSLOT_RIGHT_PCM_PLAYBACK              1
#define SRCSLOT_PHONE_LINE_1_DAC                2
#define SRCSLOT_CENTER_PCM_PLAYBACK             3
#define SRCSLOT_LEFT_SURROUND_PCM_PLAYBACK      4
#define SRCSLOT_RIGHT_SURROUND_PCM_PLAYBACK     5
#define SRCSLOT_LFE_PCM_PLAYBACK                6
#define SRCSLOT_PHONE_LINE_2_DAC                7
#define SRCSLOT_HEADSET_DAC                     8
#define SRCSLOT_LEFT_WT                         29  /* invalid for BA0_SRCSA */
#define SRCSLOT_RIGHT_WT                        30  /* invalid for BA0_SRCSA */

/* Source Slot Numbers - Capture */
#define SRCSLOT_LEFT_PCM_RECORD                 10
#define SRCSLOT_RIGHT_PCM_RECORD                11
#define SRCSLOT_PHONE_LINE_1_ADC                12
#define SRCSLOT_MIC_ADC                         13
#define SRCSLOT_PHONE_LINE_2_ADC                17
#define SRCSLOT_HEADSET_ADC                     18
#define SRCSLOT_SECONDARY_LEFT_PCM_RECORD       20
#define SRCSLOT_SECONDARY_RIGHT_PCM_RECORD      21
#define SRCSLOT_SECONDARY_PHONE_LINE_1_ADC      22
#define SRCSLOT_SECONDARY_MIC_ADC               23
#define SRCSLOT_SECONDARY_PHONE_LINE_2_ADC      27
#define SRCSLOT_SECONDARY_HEADSET_ADC           28

/* Source Slot Numbers - Others */
#define SRCSLOT_POWER_DOWN                      31

/* MIDI modes */
#define CS4281_MODE_OUTPUT              (1<<0)
#define CS4281_MODE_INPUT               (1<<1)

/* joystick bits */
/* Bits for JSPT */
#define JSPT_CAX                                0x00000001
#define JSPT_CAY                                0x00000002
#define JSPT_CBX                                0x00000004
#define JSPT_CBY                                0x00000008
#define JSPT_BA1                                0x00000010
#define JSPT_BA2                                0x00000020
#define JSPT_BB1                                0x00000040
#define JSPT_BB2                                0x00000080

/* Bits for JSCTL */
#define JSCTL_SP_MASK                           0x00000003
#define JSCTL_SP_SLOW                           0x00000000
#define JSCTL_SP_MEDIUM_SLOW                    0x00000001
#define JSCTL_SP_MEDIUM_FAST                    0x00000002
#define JSCTL_SP_FAST                           0x00000003
#define JSCTL_ARE                               0x00000004

/* Data register pairs masks */
#define JSC1_Y1V_MASK                           0x0000FFFF
#define JSC1_X1V_MASK                           0xFFFF0000
#define JSC1_Y1V_SHIFT                          0
#define JSC1_X1V_SHIFT                          16
#define JSC2_Y2V_MASK                           0x0000FFFF
#define JSC2_X2V_MASK                           0xFFFF0000
#define JSC2_Y2V_SHIFT                          0
#define JSC2_X2V_SHIFT                          16

/* JS GPIO */
#define JSIO_DAX                                0x00000001
#define JSIO_DAY                                0x00000002
#define JSIO_DBX                                0x00000004
#define JSIO_DBY                                0x00000008
#define JSIO_AXOE                               0x00000010
#define JSIO_AYOE                               0x00000020
#define JSIO_BXOE                               0x00000040
#define JSIO_BYOE                               0x00000080

/*
 *
 */

struct cs4281_dma {
        struct snd_pcm_substream *substream;
        unsigned int regDBA;            /* offset to DBA register */
        unsigned int regDCA;            /* offset to DCA register */
        unsigned int regDBC;            /* offset to DBC register */
        unsigned int regDCC;            /* offset to DCC register */
        unsigned int regDMR;            /* offset to DMR register */
        unsigned int regDCR;            /* offset to DCR register */
        unsigned int regHDSR;           /* offset to HDSR register */
        unsigned int regFCR;            /* offset to FCR register */
        unsigned int regFSIC;           /* offset to FSIC register */
        unsigned int valDMR;            /* DMA mode */
        unsigned int valDCR;            /* DMA command */
        unsigned int valFCR;            /* FIFO control */
        unsigned int fifo_offset;       /* FIFO offset within BA1 */
        unsigned char left_slot;        /* FIFO left slot */
        unsigned char right_slot;       /* FIFO right slot */
        int frag;                       /* period number */
};

#define SUSPEND_REGISTERS       20

struct cs4281 {
        int irq;

        void __iomem *ba0;              /* virtual (accessible) address */
        void __iomem *ba1;              /* virtual (accessible) address */
        unsigned long ba0_addr;
        unsigned long ba1_addr;

        int dual_codec;

        struct snd_ac97_bus *ac97_bus;
        struct snd_ac97 *ac97;
        struct snd_ac97 *ac97_secondary;

        struct pci_dev *pci;
        struct snd_card *card;
        struct snd_pcm *pcm;
        struct snd_rawmidi *rmidi;
        struct snd_rawmidi_substream *midi_input;
        struct snd_rawmidi_substream *midi_output;

        struct cs4281_dma dma[4];

        unsigned char src_left_play_slot;
        unsigned char src_right_play_slot;
        unsigned char src_left_rec_slot;
        unsigned char src_right_rec_slot;

        unsigned int spurious_dhtc_irq;
        unsigned int spurious_dtc_irq;

        spinlock_t reg_lock;
        unsigned int midcr;
        unsigned int uartm;

        struct gameport *gameport;

#ifdef CONFIG_PM_SLEEP
        u32 suspend_regs[SUSPEND_REGISTERS];
#endif

};

static irqreturn_t snd_cs4281_interrupt(int irq, void *dev_id);

static const struct pci_device_id snd_cs4281_ids[] = {
        { PCI_VDEVICE(CIRRUS, 0x6005), 0, },    /* CS4281 */
        { 0, }
};

MODULE_DEVICE_TABLE(pci, snd_cs4281_ids);

/*
 *  constants
 */

#define CS4281_FIFO_SIZE        32

/*
 *  common I/O routines
 */

static inline void snd_cs4281_pokeBA0(struct cs4281 *chip, unsigned long offset,
                                      unsigned int val)
{
        writel(val, chip->ba0 + offset);
}

static inline unsigned int snd_cs4281_peekBA0(struct cs4281 *chip, unsigned long offset)
{
        return readl(chip->ba0 + offset);
}

static void snd_cs4281_ac97_write(struct snd_ac97 *ac97,
                                  unsigned short reg, unsigned short val)
{
        /*
         *  1. Write ACCAD = Command Address Register = 46Ch for AC97 register address
         *  2. Write ACCDA = Command Data Register = 470h    for data to write to AC97
         *  3. Write ACCTL = Control Register = 460h for initiating the write
         *  4. Read ACCTL = 460h, DCV should be reset by now and 460h = 07h
         *  5. if DCV not cleared, break and return error
         */
        struct cs4281 *chip = ac97->private_data;
        int count;

        /*
         *  Setup the AC97 control registers on the CS461x to send the
         *  appropriate command to the AC97 to perform the read.
         *  ACCAD = Command Address Register = 46Ch
         *  ACCDA = Command Data Register = 470h
         *  ACCTL = Control Register = 460h
         *  set DCV - will clear when process completed
         *  reset CRW - Write command
         *  set VFRM - valid frame enabled
         *  set ESYN - ASYNC generation enabled
         *  set RSTN - ARST# inactive, AC97 codec not reset
         */
        snd_cs4281_pokeBA0(chip, BA0_ACCAD, reg);
        snd_cs4281_pokeBA0(chip, BA0_ACCDA, val);
        snd_cs4281_pokeBA0(chip, BA0_ACCTL, BA0_ACCTL_DCV | BA0_ACCTL_VFRM |
                                            BA0_ACCTL_ESYN | (ac97->num ? BA0_ACCTL_TC : 0));
        for (count = 0; count < 2000; count++) {
                /*
                 *  First, we want to wait for a short time.
                 */
                udelay(10);
                /*
                 *  Now, check to see if the write has completed.
                 *  ACCTL = 460h, DCV should be reset by now and 460h = 07h
                 */
                if (!(snd_cs4281_peekBA0(chip, BA0_ACCTL) & BA0_ACCTL_DCV)) {
                        return;
                }
        }
        dev_err(chip->card->dev,
                "AC'97 write problem, reg = 0x%x, val = 0x%x\n", reg, val);
}

static unsigned short snd_cs4281_ac97_read(struct snd_ac97 *ac97,
                                           unsigned short reg)
{
        struct cs4281 *chip = ac97->private_data;
        int count;
        unsigned short result;
        // FIXME: volatile is necessary in the following due to a bug of
        // some gcc versions
        volatile int ac97_num = ((volatile struct snd_ac97 *)ac97)->num;

        /*
         *  1. Write ACCAD = Command Address Register = 46Ch for AC97 register address
         *  2. Write ACCDA = Command Data Register = 470h    for data to write to AC97 
         *  3. Write ACCTL = Control Register = 460h for initiating the write
         *  4. Read ACCTL = 460h, DCV should be reset by now and 460h = 17h
         *  5. if DCV not cleared, break and return error
         *  6. Read ACSTS = Status Register = 464h, check VSTS bit
         */

        snd_cs4281_peekBA0(chip, ac97_num ? BA0_ACSDA2 : BA0_ACSDA);

        /*
         *  Setup the AC97 control registers on the CS461x to send the
         *  appropriate command to the AC97 to perform the read.
         *  ACCAD = Command Address Register = 46Ch
         *  ACCDA = Command Data Register = 470h
         *  ACCTL = Control Register = 460h
         *  set DCV - will clear when process completed
         *  set CRW - Read command
         *  set VFRM - valid frame enabled
         *  set ESYN - ASYNC generation enabled
         *  set RSTN - ARST# inactive, AC97 codec not reset
         */

        snd_cs4281_pokeBA0(chip, BA0_ACCAD, reg);
        snd_cs4281_pokeBA0(chip, BA0_ACCDA, 0);
        snd_cs4281_pokeBA0(chip, BA0_ACCTL, BA0_ACCTL_DCV | BA0_ACCTL_CRW |
                                            BA0_ACCTL_VFRM | BA0_ACCTL_ESYN |
                           (ac97_num ? BA0_ACCTL_TC : 0));


        /*
         *  Wait for the read to occur.
         */
        for (count = 0; count < 500; count++) {
                /*
                 *  First, we want to wait for a short time.
                 */
                udelay(10);
                /*
                 *  Now, check to see if the read has completed.
                 *  ACCTL = 460h, DCV should be reset by now and 460h = 17h
                 */
                if (!(snd_cs4281_peekBA0(chip, BA0_ACCTL) & BA0_ACCTL_DCV))
                        goto __ok1;
        }

        dev_err(chip->card->dev,
                "AC'97 read problem (ACCTL_DCV), reg = 0x%x\n", reg);
        result = 0xffff;
        goto __end;
        
      __ok1:
        /*
         *  Wait for the valid status bit to go active.
         */
        for (count = 0; count < 100; count++) {
                /*
                 *  Read the AC97 status register.
                 *  ACSTS = Status Register = 464h
                 *  VSTS - Valid Status
                 */
                if (snd_cs4281_peekBA0(chip, ac97_num ? BA0_ACSTS2 : BA0_ACSTS) & BA0_ACSTS_VSTS)
                        goto __ok2;
                udelay(10);
        }
        
        dev_err(chip->card->dev,
                "AC'97 read problem (ACSTS_VSTS), reg = 0x%x\n", reg);
        result = 0xffff;
        goto __end;

      __ok2:
        /*
         *  Read the data returned from the AC97 register.
         *  ACSDA = Status Data Register = 474h
         */
        result = snd_cs4281_peekBA0(chip, ac97_num ? BA0_ACSDA2 : BA0_ACSDA);

      __end:
        return result;
}

/*
 *  PCM part
 */

static int snd_cs4281_trigger(struct snd_pcm_substream *substream, int cmd)
{
        struct cs4281_dma *dma = substream->runtime->private_data;
        struct cs4281 *chip = snd_pcm_substream_chip(substream);

        spin_lock(&chip->reg_lock);
        switch (cmd) {
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                dma->valDCR |= BA0_DCR_MSK;
                dma->valFCR |= BA0_FCR_FEN;
                break;
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                dma->valDCR &= ~BA0_DCR_MSK;
                dma->valFCR &= ~BA0_FCR_FEN;
                break;
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_RESUME:
                snd_cs4281_pokeBA0(chip, dma->regDMR, dma->valDMR & ~BA0_DMR_DMA);
                dma->valDMR |= BA0_DMR_DMA;
                dma->valDCR &= ~BA0_DCR_MSK;
                dma->valFCR |= BA0_FCR_FEN;
                break;
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_SUSPEND:
                dma->valDMR &= ~(BA0_DMR_DMA|BA0_DMR_POLL);
                dma->valDCR |= BA0_DCR_MSK;
                dma->valFCR &= ~BA0_FCR_FEN;
                /* Leave wave playback FIFO enabled for FM */
                if (dma->regFCR != BA0_FCR0)
                        dma->valFCR &= ~BA0_FCR_FEN;
                break;
        default:
                spin_unlock(&chip->reg_lock);
                return -EINVAL;
        }
        snd_cs4281_pokeBA0(chip, dma->regDMR, dma->valDMR);
        snd_cs4281_pokeBA0(chip, dma->regFCR, dma->valFCR);
        snd_cs4281_pokeBA0(chip, dma->regDCR, dma->valDCR);
        spin_unlock(&chip->reg_lock);
        return 0;
}

static unsigned int snd_cs4281_rate(unsigned int rate, unsigned int *real_rate)
{
        unsigned int val = ~0;
        
        if (real_rate)
                *real_rate = rate;
        /* special "hardcoded" rates */
        switch (rate) {
        case 8000:      return 5;
        case 11025:     return 4;
        case 16000:     return 3;
        case 22050:     return 2;
        case 44100:     return 1;
        case 48000:     return 0;
        default:
                goto __variable;
        }
      __variable:
        val = 1536000 / rate;
        if (real_rate)
                *real_rate = 1536000 / val;
        return val;
}

static void snd_cs4281_mode(struct cs4281 *chip, struct cs4281_dma *dma,
                            struct snd_pcm_runtime *runtime,
                            int capture, int src)
{
        int rec_mono;

        dma->valDMR = BA0_DMR_TYPE_SINGLE | BA0_DMR_AUTO |
                      (capture ? BA0_DMR_TR_WRITE : BA0_DMR_TR_READ);
        if (runtime->channels == 1)
                dma->valDMR |= BA0_DMR_MONO;
        if (snd_pcm_format_unsigned(runtime->format) > 0)
                dma->valDMR |= BA0_DMR_USIGN;
        if (snd_pcm_format_big_endian(runtime->format) > 0)
                dma->valDMR |= BA0_DMR_BEND;
        switch (snd_pcm_format_width(runtime->format)) {
        case 8: dma->valDMR |= BA0_DMR_SIZE8;
                if (runtime->channels == 1)
                        dma->valDMR |= BA0_DMR_SWAPC;
                break;
        case 32: dma->valDMR |= BA0_DMR_SIZE20; break;
        }
        dma->frag = 0;  /* for workaround */
        dma->valDCR = BA0_DCR_TCIE | BA0_DCR_MSK;
        if (runtime->buffer_size != runtime->period_size)
                dma->valDCR |= BA0_DCR_HTCIE;
        /* Initialize DMA */
        snd_cs4281_pokeBA0(chip, dma->regDBA, runtime->dma_addr);
        snd_cs4281_pokeBA0(chip, dma->regDBC, runtime->buffer_size - 1);
        rec_mono = (chip->dma[1].valDMR & BA0_DMR_MONO) == BA0_DMR_MONO;
        snd_cs4281_pokeBA0(chip, BA0_SRCSA, (chip->src_left_play_slot << 0) |
                                            (chip->src_right_play_slot << 8) |
                                            (chip->src_left_rec_slot << 16) |
                                            ((rec_mono ? 31 : chip->src_right_rec_slot) << 24));
        if (!src)
                goto __skip_src;
        if (!capture) {
                if (dma->left_slot == chip->src_left_play_slot) {
                        unsigned int val = snd_cs4281_rate(runtime->rate, NULL);
                        snd_BUG_ON(dma->right_slot != chip->src_right_play_slot);
                        snd_cs4281_pokeBA0(chip, BA0_DACSR, val);
                }
        } else {
                if (dma->left_slot == chip->src_left_rec_slot) {
                        unsigned int val = snd_cs4281_rate(runtime->rate, NULL);
                        snd_BUG_ON(dma->right_slot != chip->src_right_rec_slot);
                        snd_cs4281_pokeBA0(chip, BA0_ADCSR, val);
                }
        }
      __skip_src:
        /* Deactivate wave playback FIFO before changing slot assignments */
        if (dma->regFCR == BA0_FCR0)
                snd_cs4281_pokeBA0(chip, dma->regFCR, snd_cs4281_peekBA0(chip, dma->regFCR) & ~BA0_FCR_FEN);
        /* Initialize FIFO */
        dma->valFCR = BA0_FCR_LS(dma->left_slot) |
                      BA0_FCR_RS(capture && (dma->valDMR & BA0_DMR_MONO) ? 31 : dma->right_slot) |
                      BA0_FCR_SZ(CS4281_FIFO_SIZE) |
                      BA0_FCR_OF(dma->fifo_offset);
        snd_cs4281_pokeBA0(chip, dma->regFCR, dma->valFCR | (capture ? BA0_FCR_PSH : 0));
        /* Activate FIFO again for FM playback */
        if (dma->regFCR == BA0_FCR0)
                snd_cs4281_pokeBA0(chip, dma->regFCR, dma->valFCR | BA0_FCR_FEN);
        /* Clear FIFO Status and Interrupt Control Register */
        snd_cs4281_pokeBA0(chip, dma->regFSIC, 0);
}

static int snd_cs4281_hw_params(struct snd_pcm_substream *substream,
                                struct snd_pcm_hw_params *hw_params)
{
        return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(hw_params));
}

static int snd_cs4281_hw_free(struct snd_pcm_substream *substream)
{
        return snd_pcm_lib_free_pages(substream);
}

static int snd_cs4281_playback_prepare(struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct cs4281_dma *dma = runtime->private_data;
        struct cs4281 *chip = snd_pcm_substream_chip(substream);

        spin_lock_irq(&chip->reg_lock);
        snd_cs4281_mode(chip, dma, runtime, 0, 1);
        spin_unlock_irq(&chip->reg_lock);
        return 0;
}

static int snd_cs4281_capture_prepare(struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct cs4281_dma *dma = runtime->private_data;
        struct cs4281 *chip = snd_pcm_substream_chip(substream);

        spin_lock_irq(&chip->reg_lock);
        snd_cs4281_mode(chip, dma, runtime, 1, 1);
        spin_unlock_irq(&chip->reg_lock);
        return 0;
}

static snd_pcm_uframes_t snd_cs4281_pointer(struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct cs4281_dma *dma = runtime->private_data;
        struct cs4281 *chip = snd_pcm_substream_chip(substream);

        /*
        dev_dbg(chip->card->dev,
                "DCC = 0x%x, buffer_size = 0x%x, jiffies = %li\n",
                snd_cs4281_peekBA0(chip, dma->regDCC), runtime->buffer_size,
               jiffies);
        */
        return runtime->buffer_size -
               snd_cs4281_peekBA0(chip, dma->regDCC) - 1;
}

static struct snd_pcm_hardware snd_cs4281_playback =
{
        .info =                 SNDRV_PCM_INFO_MMAP |
                                SNDRV_PCM_INFO_INTERLEAVED |
                                SNDRV_PCM_INFO_MMAP_VALID |
                                SNDRV_PCM_INFO_PAUSE |
                                SNDRV_PCM_INFO_RESUME,
        .formats =              SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S8 |
                                SNDRV_PCM_FMTBIT_U16_LE | SNDRV_PCM_FMTBIT_S16_LE |
                                SNDRV_PCM_FMTBIT_U16_BE | SNDRV_PCM_FMTBIT_S16_BE |
                                SNDRV_PCM_FMTBIT_U32_LE | SNDRV_PCM_FMTBIT_S32_LE |
                                SNDRV_PCM_FMTBIT_U32_BE | SNDRV_PCM_FMTBIT_S32_BE,
        .rates =                SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000,
        .rate_min =             4000,
        .rate_max =             48000,
        .channels_min =         1,
        .channels_max =         2,
        .buffer_bytes_max =     (512*1024),
        .period_bytes_min =     64,
        .period_bytes_max =     (512*1024),
        .periods_min =          1,
        .periods_max =          2,
        .fifo_size =            CS4281_FIFO_SIZE,
};

static struct snd_pcm_hardware snd_cs4281_capture =
{
        .info =                 SNDRV_PCM_INFO_MMAP |
                                SNDRV_PCM_INFO_INTERLEAVED |
                                SNDRV_PCM_INFO_MMAP_VALID |
                                SNDRV_PCM_INFO_PAUSE |
                                SNDRV_PCM_INFO_RESUME,
        .formats =              SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S8 |
                                SNDRV_PCM_FMTBIT_U16_LE | SNDRV_PCM_FMTBIT_S16_LE |
                                SNDRV_PCM_FMTBIT_U16_BE | SNDRV_PCM_FMTBIT_S16_BE |
                                SNDRV_PCM_FMTBIT_U32_LE | SNDRV_PCM_FMTBIT_S32_LE |
                                SNDRV_PCM_FMTBIT_U32_BE | SNDRV_PCM_FMTBIT_S32_BE,
        .rates =                SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000,
        .rate_min =             4000,
        .rate_max =             48000,
        .channels_min =         1,
        .channels_max =         2,
        .buffer_bytes_max =     (512*1024),
        .period_bytes_min =     64,
        .period_bytes_max =     (512*1024),
        .periods_min =          1,
        .periods_max =          2,
        .fifo_size =            CS4281_FIFO_SIZE,
};

static int snd_cs4281_playback_open(struct snd_pcm_substream *substream)
{
        struct cs4281 *chip = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct cs4281_dma *dma;

        dma = &chip->dma[0];
        dma->substream = substream;
        dma->left_slot = 0;
        dma->right_slot = 1;
        runtime->private_data = dma;
        runtime->hw = snd_cs4281_playback;
        /* should be detected from the AC'97 layer, but it seems
           that although CS4297A rev B reports 18-bit ADC resolution,
           samples are 20-bit */
        snd_pcm_hw_constraint_msbits(runtime, 0, 32, 20);
        return 0;
}

static int snd_cs4281_capture_open(struct snd_pcm_substream *substream)
{
        struct cs4281 *chip = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct cs4281_dma *dma;

        dma = &chip->dma[1];
        dma->substream = substream;
        dma->left_slot = 10;
        dma->right_slot = 11;
        runtime->private_data = dma;
        runtime->hw = snd_cs4281_capture;
        /* should be detected from the AC'97 layer, but it seems
           that although CS4297A rev B reports 18-bit ADC resolution,
           samples are 20-bit */
        snd_pcm_hw_constraint_msbits(runtime, 0, 32, 20);
        return 0;
}

static int snd_cs4281_playback_close(struct snd_pcm_substream *substream)
{
        struct cs4281_dma *dma = substream->runtime->private_data;

        dma->substream = NULL;
        return 0;
}

static int snd_cs4281_capture_close(struct snd_pcm_substream *substream)
{
        struct cs4281_dma *dma = substream->runtime->private_data;

        dma->substream = NULL;
        return 0;
}

static struct snd_pcm_ops snd_cs4281_playback_ops = {
        .open =         snd_cs4281_playback_open,
        .close =        snd_cs4281_playback_close,
        .ioctl =        snd_pcm_lib_ioctl,
        .hw_params =    snd_cs4281_hw_params,
        .hw_free =      snd_cs4281_hw_free,
        .prepare =      snd_cs4281_playback_prepare,
        .trigger =      snd_cs4281_trigger,
        .pointer =      snd_cs4281_pointer,
};

static struct snd_pcm_ops snd_cs4281_capture_ops = {
        .open =         snd_cs4281_capture_open,
        .close =        snd_cs4281_capture_close,
        .ioctl =        snd_pcm_lib_ioctl,
        .hw_params =    snd_cs4281_hw_params,
        .hw_free =      snd_cs4281_hw_free,
        .prepare =      snd_cs4281_capture_prepare,
        .trigger =      snd_cs4281_trigger,
        .pointer =      snd_cs4281_pointer,
};

static int snd_cs4281_pcm(struct cs4281 *chip, int device,
                          struct snd_pcm **rpcm)
{
        struct snd_pcm *pcm;
        int err;

        if (rpcm)
                *rpcm = NULL;
        err = snd_pcm_new(chip->card, "CS4281", device, 1, 1, &pcm);
        if (err < 0)
                return err;

        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_cs4281_playback_ops);
        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_cs4281_capture_ops);

        pcm->private_data = chip;
        pcm->info_flags = 0;
        strcpy(pcm->name, "CS4281");
        chip->pcm = pcm;

        snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
                                              snd_dma_pci_data(chip->pci), 64*1024, 512*1024);

        if (rpcm)
                *rpcm = pcm;

        return 0;
}

/*
 *  Mixer section
 */

#define CS_VOL_MASK     0x1f

static int snd_cs4281_info_volume(struct snd_kcontrol *kcontrol,
                                  struct snd_ctl_elem_info *uinfo)
{
        uinfo->type              = SNDRV_CTL_ELEM_TYPE_INTEGER;
        uinfo->count             = 2;
        uinfo->value.integer.min = 0;
        uinfo->value.integer.max = CS_VOL_MASK;
        return 0;
}
 
static int snd_cs4281_get_volume(struct snd_kcontrol *kcontrol,
                                 struct snd_ctl_elem_value *ucontrol)
{
        struct cs4281 *chip = snd_kcontrol_chip(kcontrol);
        int regL = (kcontrol->private_value >> 16) & 0xffff;
        int regR = kcontrol->private_value & 0xffff;
        int volL, volR;

        volL = CS_VOL_MASK - (snd_cs4281_peekBA0(chip, regL) & CS_VOL_MASK);
        volR = CS_VOL_MASK - (snd_cs4281_peekBA0(chip, regR) & CS_VOL_MASK);

        ucontrol->value.integer.value[0] = volL;
        ucontrol->value.integer.value[1] = volR;
        return 0;
}

static int snd_cs4281_put_volume(struct snd_kcontrol *kcontrol,
                                 struct snd_ctl_elem_value *ucontrol)
{
        struct cs4281 *chip = snd_kcontrol_chip(kcontrol);
        int change = 0;
        int regL = (kcontrol->private_value >> 16) & 0xffff;
        int regR = kcontrol->private_value & 0xffff;
        int volL, volR;

        volL = CS_VOL_MASK - (snd_cs4281_peekBA0(chip, regL) & CS_VOL_MASK);
        volR = CS_VOL_MASK - (snd_cs4281_peekBA0(chip, regR) & CS_VOL_MASK);

        if (ucontrol->value.integer.value[0] != volL) {
                volL = CS_VOL_MASK - (ucontrol->value.integer.value[0] & CS_VOL_MASK);
                snd_cs4281_pokeBA0(chip, regL, volL);
                change = 1;
        }
        if (ucontrol->value.integer.value[1] != volR) {
                volR = CS_VOL_MASK - (ucontrol->value.integer.value[1] & CS_VOL_MASK);
                snd_cs4281_pokeBA0(chip, regR, volR);
                change = 1;
        }
        return change;
}

static const DECLARE_TLV_DB_SCALE(db_scale_dsp, -4650, 150, 0);

static struct snd_kcontrol_new snd_cs4281_fm_vol = 
{
        .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
        .name = "Synth Playback Volume",
        .info = snd_cs4281_info_volume, 
        .get = snd_cs4281_get_volume,
        .put = snd_cs4281_put_volume, 
        .private_value = ((BA0_FMLVC << 16) | BA0_FMRVC),
        .tlv = { .p = db_scale_dsp },
};

static struct snd_kcontrol_new snd_cs4281_pcm_vol = 
{
        .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
        .name = "PCM Stream Playback Volume",
        .info = snd_cs4281_info_volume, 
        .get = snd_cs4281_get_volume,
        .put = snd_cs4281_put_volume, 
        .private_value = ((BA0_PPLVC << 16) | BA0_PPRVC),
        .tlv = { .p = db_scale_dsp },
};

static void snd_cs4281_mixer_free_ac97_bus(struct snd_ac97_bus *bus)
{
        struct cs4281 *chip = bus->private_data;
        chip->ac97_bus = NULL;
}

static void snd_cs4281_mixer_free_ac97(struct snd_ac97 *ac97)
{
        struct cs4281 *chip = ac97->private_data;
        if (ac97->num)
                chip->ac97_secondary = NULL;
        else
                chip->ac97 = NULL;
}

static int snd_cs4281_mixer(struct cs4281 *chip)
{
        struct snd_card *card = chip->card;
        struct snd_ac97_template ac97;
        int err;
        static struct snd_ac97_bus_ops ops = {
                .write = snd_cs4281_ac97_write,
                .read = snd_cs4281_ac97_read,
        };

        if ((err = snd_ac97_bus(card, 0, &ops, chip, &chip->ac97_bus)) < 0)
                return err;
        chip->ac97_bus->private_free = snd_cs4281_mixer_free_ac97_bus;

        memset(&ac97, 0, sizeof(ac97));
        ac97.private_data = chip;
        ac97.private_free = snd_cs4281_mixer_free_ac97;
        if ((err = snd_ac97_mixer(chip->ac97_bus, &ac97, &chip->ac97)) < 0)
                return err;
        if (chip->dual_codec) {
                ac97.num = 1;
                if ((err = snd_ac97_mixer(chip->ac97_bus, &ac97, &chip->ac97_secondary)) < 0)
                        return err;
        }
        if ((err = snd_ctl_add(card, snd_ctl_new1(&snd_cs4281_fm_vol, chip))) < 0)
                return err;
        if ((err = snd_ctl_add(card, snd_ctl_new1(&snd_cs4281_pcm_vol, chip))) < 0)
                return err;
        return 0;
}


/*
 * proc interface
 */

static void snd_cs4281_proc_read(struct snd_info_entry *entry, 
                                  struct snd_info_buffer *buffer)
{
        struct cs4281 *chip = entry->private_data;

        snd_iprintf(buffer, "Cirrus Logic CS4281\n\n");
        snd_iprintf(buffer, "Spurious half IRQs   : %u\n", chip->spurious_dhtc_irq);
        snd_iprintf(buffer, "Spurious end IRQs    : %u\n", chip->spurious_dtc_irq);
}

static ssize_t snd_cs4281_BA0_read(struct snd_info_entry *entry,
                                   void *file_private_data,
                                   struct file *file, char __user *buf,
                                   size_t count, loff_t pos)
{
        struct cs4281 *chip = entry->private_data;
        
        if (copy_to_user_fromio(buf, chip->ba0 + pos, count))
                return -EFAULT;
        return count;
}

static ssize_t snd_cs4281_BA1_read(struct snd_info_entry *entry,
                                   void *file_private_data,
                                   struct file *file, char __user *buf,
                                   size_t count, loff_t pos)
{
        struct cs4281 *chip = entry->private_data;
        
        if (copy_to_user_fromio(buf, chip->ba1 + pos, count))
                return -EFAULT;
        return count;
}

static struct snd_info_entry_ops snd_cs4281_proc_ops_BA0 = {
        .read = snd_cs4281_BA0_read,
};

static struct snd_info_entry_ops snd_cs4281_proc_ops_BA1 = {
        .read = snd_cs4281_BA1_read,
};

static void snd_cs4281_proc_init(struct cs4281 *chip)
{
        struct snd_info_entry *entry;

        if (! snd_card_proc_new(chip->card, "cs4281", &entry))
                snd_info_set_text_ops(entry, chip, snd_cs4281_proc_read);
        if (! snd_card_proc_new(chip->card, "cs4281_BA0", &entry)) {
                entry->content = SNDRV_INFO_CONTENT_DATA;
                entry->private_data = chip;
                entry->c.ops = &snd_cs4281_proc_ops_BA0;
                entry->size = CS4281_BA0_SIZE;
        }
        if (! snd_card_proc_new(chip->card, "cs4281_BA1", &entry)) {
                entry->content = SNDRV_INFO_CONTENT_DATA;
                entry->private_data = chip;
                entry->c.ops = &snd_cs4281_proc_ops_BA1;
                entry->size = CS4281_BA1_SIZE;
        }
}

/*
 * joystick support
 */

#if defined(CONFIG_GAMEPORT) || (defined(MODULE) && defined(CONFIG_GAMEPORT_MODULE))

static void snd_cs4281_gameport_trigger(struct gameport *gameport)
{
        struct cs4281 *chip = gameport_get_port_data(gameport);

        if (snd_BUG_ON(!chip))
                return;
        snd_cs4281_pokeBA0(chip, BA0_JSPT, 0xff);
}

static unsigned char snd_cs4281_gameport_read(struct gameport *gameport)
{
        struct cs4281 *chip = gameport_get_port_data(gameport);

        if (snd_BUG_ON(!chip))
                return 0;
        return snd_cs4281_peekBA0(chip, BA0_JSPT);
}

#ifdef COOKED_MODE
static int snd_cs4281_gameport_cooked_read(struct gameport *gameport,
                                           int *axes, int *buttons)
{
        struct cs4281 *chip = gameport_get_port_data(gameport);
        unsigned js1, js2, jst;
        
        if (snd_BUG_ON(!chip))
                return 0;

        js1 = snd_cs4281_peekBA0(chip, BA0_JSC1);
        js2 = snd_cs4281_peekBA0(chip, BA0_JSC2);
        jst = snd_cs4281_peekBA0(chip, BA0_JSPT);
        
        *buttons = (~jst >> 4) & 0x0F; 
        
        axes[0] = ((js1 & JSC1_Y1V_MASK) >> JSC1_Y1V_SHIFT) & 0xFFFF;
        axes[1] = ((js1 & JSC1_X1V_MASK) >> JSC1_X1V_SHIFT) & 0xFFFF;
        axes[2] = ((js2 & JSC2_Y2V_MASK) >> JSC2_Y2V_SHIFT) & 0xFFFF;
        axes[3] = ((js2 & JSC2_X2V_MASK) >> JSC2_X2V_SHIFT) & 0xFFFF;

        for (jst = 0; jst < 4; ++jst)
                if (axes[jst] == 0xFFFF) axes[jst] = -1;
        return 0;
}
#else
#define snd_cs4281_gameport_cooked_read NULL
#endif

static int snd_cs4281_gameport_open(struct gameport *gameport, int mode)
{
        switch (mode) {
#ifdef COOKED_MODE
        case GAMEPORT_MODE_COOKED:
                return 0;
#endif
        case GAMEPORT_MODE_RAW:
                return 0;
        default:
                return -1;
        }
        return 0;
}

static int snd_cs4281_create_gameport(struct cs4281 *chip)
{
        struct gameport *gp;

        chip->gameport = gp = gameport_allocate_port();
        if (!gp) {
                dev_err(chip->card->dev,
                        "cannot allocate memory for gameport\n");
                return -ENOMEM;
        }

        gameport_set_name(gp, "CS4281 Gameport");
        gameport_set_phys(gp, "pci%s/gameport0", pci_name(chip->pci));
        gameport_set_dev_parent(gp, &chip->pci->dev);
        gp->open = snd_cs4281_gameport_open;
        gp->read = snd_cs4281_gameport_read;
        gp->trigger = snd_cs4281_gameport_trigger;
        gp->cooked_read = snd_cs4281_gameport_cooked_read;
        gameport_set_port_data(gp, chip);

        snd_cs4281_pokeBA0(chip, BA0_JSIO, 0xFF); // ?
        snd_cs4281_pokeBA0(chip, BA0_JSCTL, JSCTL_SP_MEDIUM_SLOW);

        gameport_register_port(gp);

        return 0;
}

static void snd_cs4281_free_gameport(struct cs4281 *chip)
{
        if (chip->gameport) {
                gameport_unregister_port(chip->gameport);
                chip->gameport = NULL;
        }
}
#else
static inline int snd_cs4281_create_gameport(struct cs4281 *chip) { return -ENOSYS; }
static inline void snd_cs4281_free_gameport(struct cs4281 *chip) { }
#endif /* CONFIG_GAMEPORT || (MODULE && CONFIG_GAMEPORT_MODULE) */

static int snd_cs4281_free(struct cs4281 *chip)
{
        snd_cs4281_free_gameport(chip);

        if (chip->irq >= 0)
                synchronize_irq(chip->irq);

        /* Mask interrupts */
        snd_cs4281_pokeBA0(chip, BA0_HIMR, 0x7fffffff);
        /* Stop the DLL Clock logic. */
        snd_cs4281_pokeBA0(chip, BA0_CLKCR1, 0);
        /* Sound System Power Management - Turn Everything OFF */
        snd_cs4281_pokeBA0(chip, BA0_SSPM, 0);
        /* PCI interface - D3 state */
        pci_set_power_state(chip->pci, PCI_D3hot);

        if (chip->irq >= 0)
                free_irq(chip->irq, chip);
        if (chip->ba0)
                iounmap(chip->ba0);
        if (chip->ba1)
                iounmap(chip->ba1);
        pci_release_regions(chip->pci);
        pci_disable_device(chip->pci);

        kfree(chip);
        return 0;
}

static int snd_cs4281_dev_free(struct snd_device *device)
{
        struct cs4281 *chip = device->device_data;
        return snd_cs4281_free(chip);
}

static int snd_cs4281_chip_init(struct cs4281 *chip); /* defined below */

static int snd_cs4281_create(struct snd_card *card,
                             struct pci_dev *pci,
                             struct cs4281 **rchip,
                             int dual_codec)
{
        struct cs4281 *chip;
        unsigned int tmp;
        int err;
        static struct snd_device_ops ops = {
                .dev_free =     snd_cs4281_dev_free,
        };

        *rchip = NULL;
        if ((err = pci_enable_device(pci)) < 0)
                return err;
        chip = kzalloc(sizeof(*chip), GFP_KERNEL);
        if (chip == NULL) {
                pci_disable_device(pci);
                return -ENOMEM;
        }
        spin_lock_init(&chip->reg_lock);
        chip->card = card;
        chip->pci = pci;
        chip->irq = -1;
        pci_set_master(pci);
        if (dual_codec < 0 || dual_codec > 3) {
                dev_err(card->dev, "invalid dual_codec option %d\n", dual_codec);
                dual_codec = 0;
        }
        chip->dual_codec = dual_codec;

        if ((err = pci_request_regions(pci, "CS4281")) < 0) {
                kfree(chip);
                pci_disable_device(pci);
                return err;
        }
        chip->ba0_addr = pci_resource_start(pci, 0);
        chip->ba1_addr = pci_resource_start(pci, 1);

        chip->ba0 = pci_ioremap_bar(pci, 0);
        chip->ba1 = pci_ioremap_bar(pci, 1);
        if (!chip->ba0 || !chip->ba1) {
                snd_cs4281_free(chip);
                return -ENOMEM;
        }
        
        if (request_irq(pci->irq, snd_cs4281_interrupt, IRQF_SHARED,
                        KBUILD_MODNAME, chip)) {
                dev_err(card->dev, "unable to grab IRQ %d\n", pci->irq);
                snd_cs4281_free(chip);
                return -ENOMEM;
        }
        chip->irq = pci->irq;

        tmp = snd_cs4281_chip_init(chip);
        if (tmp) {
                snd_cs4281_free(chip);
                return tmp;
        }

        if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
                snd_cs4281_free(chip);
                return err;
        }

        snd_cs4281_proc_init(chip);

        *rchip = chip;
        return 0;
}

static int snd_cs4281_chip_init(struct cs4281 *chip)
{
        unsigned int tmp;
        unsigned long end_time;
        int retry_count = 2;

        /* Having EPPMC.FPDN=1 prevent proper chip initialisation */
        tmp = snd_cs4281_peekBA0(chip, BA0_EPPMC);
        if (tmp & BA0_EPPMC_FPDN)
                snd_cs4281_pokeBA0(chip, BA0_EPPMC, tmp & ~BA0_EPPMC_FPDN);

      __retry:
        tmp = snd_cs4281_peekBA0(chip, BA0_CFLR);
        if (tmp != BA0_CFLR_DEFAULT) {
                snd_cs4281_pokeBA0(chip, BA0_CFLR, BA0_CFLR_DEFAULT);
                tmp = snd_cs4281_peekBA0(chip, BA0_CFLR);
                if (tmp != BA0_CFLR_DEFAULT) {
                        dev_err(chip->card->dev,
                                "CFLR setup failed (0x%x)\n", tmp);
                        return -EIO;
                }
        }

        /* Set the 'Configuration Write Protect' register
         * to 4281h.  Allows vendor-defined configuration
         * space between 0e4h and 0ffh to be written. */        
        snd_cs4281_pokeBA0(chip, BA0_CWPR, 0x4281);
        
        if ((tmp = snd_cs4281_peekBA0(chip, BA0_SERC1)) != (BA0_SERC1_SO1EN | BA0_SERC1_AC97)) {
                dev_err(chip->card->dev,
                        "SERC1 AC'97 check failed (0x%x)\n", tmp);
                return -EIO;
        }
        if ((tmp = snd_cs4281_peekBA0(chip, BA0_SERC2)) != (BA0_SERC2_SI1EN | BA0_SERC2_AC97)) {
                dev_err(chip->card->dev,
                        "SERC2 AC'97 check failed (0x%x)\n", tmp);
                return -EIO;
        }

        /* Sound System Power Management */
        snd_cs4281_pokeBA0(chip, BA0_SSPM, BA0_SSPM_MIXEN | BA0_SSPM_CSRCEN |
                                           BA0_SSPM_PSRCEN | BA0_SSPM_JSEN |
                                           BA0_SSPM_ACLEN | BA0_SSPM_FMEN);

        /* Serial Port Power Management */
        /* Blast the clock control register to zero so that the
         * PLL starts out in a known state, and blast the master serial
         * port control register to zero so that the serial ports also
         * start out in a known state. */
        snd_cs4281_pokeBA0(chip, BA0_CLKCR1, 0);
        snd_cs4281_pokeBA0(chip, BA0_SERMC, 0);

        /* Make ESYN go to zero to turn off
         * the Sync pulse on the AC97 link. */
        snd_cs4281_pokeBA0(chip, BA0_ACCTL, 0);
        udelay(50);
                
        /*  Drive the ARST# pin low for a minimum of 1uS (as defined in the AC97
         *  spec) and then drive it high.  This is done for non AC97 modes since
         *  there might be logic external to the CS4281 that uses the ARST# line
         *  for a reset. */
        snd_cs4281_pokeBA0(chip, BA0_SPMC, 0);
        udelay(50);
        snd_cs4281_pokeBA0(chip, BA0_SPMC, BA0_SPMC_RSTN);
        msleep(50);

        if (chip->dual_codec)
                snd_cs4281_pokeBA0(chip, BA0_SPMC, BA0_SPMC_RSTN | BA0_SPMC_ASDI2E);

        /*
         *  Set the serial port timing configuration.
         */
        snd_cs4281_pokeBA0(chip, BA0_SERMC,
                           (chip->dual_codec ? BA0_SERMC_TCID(chip->dual_codec) : BA0_SERMC_TCID(1)) |
                           BA0_SERMC_PTC_AC97 | BA0_SERMC_MSPE);

        /*
         *  Start the DLL Clock logic.
         */
        snd_cs4281_pokeBA0(chip, BA0_CLKCR1, BA0_CLKCR1_DLLP);
        msleep(50);
        snd_cs4281_pokeBA0(chip, BA0_CLKCR1, BA0_CLKCR1_SWCE | BA0_CLKCR1_DLLP);

        /*
         * Wait for the DLL ready signal from the clock logic.
         */
        end_time = jiffies + HZ;
        do {
                /*
                 *  Read the AC97 status register to see if we've seen a CODEC
                 *  signal from the AC97 codec.
                 */
                if (snd_cs4281_peekBA0(chip, BA0_CLKCR1) & BA0_CLKCR1_DLLRDY)
                        goto __ok0;
                schedule_timeout_uninterruptible(1);
        } while (time_after_eq(end_time, jiffies));

        dev_err(chip->card->dev, "DLLRDY not seen\n");
        return -EIO;

      __ok0:

        /*
         *  The first thing we do here is to enable sync generation.  As soon
         *  as we start receiving bit clock, we'll start producing the SYNC
         *  signal.
         */
        snd_cs4281_pokeBA0(chip, BA0_ACCTL, BA0_ACCTL_ESYN);

        /*
         * Wait for the codec ready signal from the AC97 codec.
         */
        end_time = jiffies + HZ;
        do {
                /*
                 *  Read the AC97 status register to see if we've seen a CODEC
                 *  signal from the AC97 codec.
                 */
                if (snd_cs4281_peekBA0(chip, BA0_ACSTS) & BA0_ACSTS_CRDY)
                        goto __ok1;
                schedule_timeout_uninterruptible(1);
        } while (time_after_eq(end_time, jiffies));

        dev_err(chip->card->dev,
                "never read codec ready from AC'97 (0x%x)\n",
                snd_cs4281_peekBA0(chip, BA0_ACSTS));
        return -EIO;

      __ok1:
        if (chip->dual_codec) {
                end_time = jiffies + HZ;
                do {
                        if (snd_cs4281_peekBA0(chip, BA0_ACSTS2) & BA0_ACSTS_CRDY)
                                goto __codec2_ok;
                        schedule_timeout_uninterruptible(1);
                } while (time_after_eq(end_time, jiffies));
                dev_info(chip->card->dev,
                         "secondary codec doesn't respond. disable it...\n");
                chip->dual_codec = 0;
        __codec2_ok: ;
        }

        /*
         *  Assert the valid frame signal so that we can start sending commands
         *  to the AC97 codec.
         */

        snd_cs4281_pokeBA0(chip, BA0_ACCTL, BA0_ACCTL_VFRM | BA0_ACCTL_ESYN);

        /*
         *  Wait until we've sampled input slots 3 and 4 as valid, meaning that
         *  the codec is pumping ADC data across the AC-link.
         */

        end_time = jiffies + HZ;
        do {
                /*
                 *  Read the input slot valid register and see if input slots 3
                 *  4 are valid yet.
                 */
                if ((snd_cs4281_peekBA0(chip, BA0_ACISV) & (BA0_ACISV_SLV(3) | BA0_ACISV_SLV(4))) == (BA0_ACISV_SLV(3) | BA0_ACISV_SLV(4)))
                        goto __ok2;
                schedule_timeout_uninterruptible(1);
        } while (time_after_eq(end_time, jiffies));

        if (--retry_count > 0)
                goto __retry;
        dev_err(chip->card->dev, "never read ISV3 and ISV4 from AC'97\n");
        return -EIO;

      __ok2:

        /*
         *  Now, assert valid frame and the slot 3 and 4 valid bits.  This will
         *  commense the transfer of digital audio data to the AC97 codec.
         */
        snd_cs4281_pokeBA0(chip, BA0_ACOSV, BA0_ACOSV_SLV(3) | BA0_ACOSV_SLV(4));

        /*
         *  Initialize DMA structures
         */
        for (tmp = 0; tmp < 4; tmp++) {
                struct cs4281_dma *dma = &chip->dma[tmp];
                dma->regDBA = BA0_DBA0 + (tmp * 0x10);
                dma->regDCA = BA0_DCA0 + (tmp * 0x10);
                dma->regDBC = BA0_DBC0 + (tmp * 0x10);
                dma->regDCC = BA0_DCC0 + (tmp * 0x10);
                dma->regDMR = BA0_DMR0 + (tmp * 8);
                dma->regDCR = BA0_DCR0 + (tmp * 8);
                dma->regHDSR = BA0_HDSR0 + (tmp * 4);
                dma->regFCR = BA0_FCR0 + (tmp * 4);
                dma->regFSIC = BA0_FSIC0 + (tmp * 4);
                dma->fifo_offset = tmp * CS4281_FIFO_SIZE;
                snd_cs4281_pokeBA0(chip, dma->regFCR,
                                   BA0_FCR_LS(31) |
                                   BA0_FCR_RS(31) |
                                   BA0_FCR_SZ(CS4281_FIFO_SIZE) |
                                   BA0_FCR_OF(dma->fifo_offset));
        }

        chip->src_left_play_slot = 0;   /* AC'97 left PCM playback (3) */
        chip->src_right_play_slot = 1;  /* AC'97 right PCM playback (4) */
        chip->src_left_rec_slot = 10;   /* AC'97 left PCM record (3) */
        chip->src_right_rec_slot = 11;  /* AC'97 right PCM record (4) */

        /* Activate wave playback FIFO for FM playback */
        chip->dma[0].valFCR = BA0_FCR_FEN | BA0_FCR_LS(0) |
                              BA0_FCR_RS(1) |
                              BA0_FCR_SZ(CS4281_FIFO_SIZE) |
                              BA0_FCR_OF(chip->dma[0].fifo_offset);
        snd_cs4281_pokeBA0(chip, chip->dma[0].regFCR, chip->dma[0].valFCR);
        snd_cs4281_pokeBA0(chip, BA0_SRCSA, (chip->src_left_play_slot << 0) |
                                            (chip->src_right_play_slot << 8) |
                                            (chip->src_left_rec_slot << 16) |
                                            (chip->src_right_rec_slot << 24));

        /* Initialize digital volume */
        snd_cs4281_pokeBA0(chip, BA0_PPLVC, 0);
        snd_cs4281_pokeBA0(chip, BA0_PPRVC, 0);

        /* Enable IRQs */
        snd_cs4281_pokeBA0(chip, BA0_HICR, BA0_HICR_EOI);
        /* Unmask interrupts */
        snd_cs4281_pokeBA0(chip, BA0_HIMR, 0x7fffffff & ~(
                                        BA0_HISR_MIDI |
                                        BA0_HISR_DMAI |
                                        BA0_HISR_DMA(0) |
                                        BA0_HISR_DMA(1) |
                                        BA0_HISR_DMA(2) |
                                        BA0_HISR_DMA(3)));
        synchronize_irq(chip->irq);

        return 0;
}

/*
 *  MIDI section
 */

static void snd_cs4281_midi_reset(struct cs4281 *chip)
{
        snd_cs4281_pokeBA0(chip, BA0_MIDCR, chip->midcr | BA0_MIDCR_MRST);
        udelay(100);
        snd_cs4281_pokeBA0(chip, BA0_MIDCR, chip->midcr);
}

static int snd_cs4281_midi_input_open(struct snd_rawmidi_substream *substream)
{
        struct cs4281 *chip = substream->rmidi->private_data;

        spin_lock_irq(&chip->reg_lock);
        chip->midcr |= BA0_MIDCR_RXE;
        chip->midi_input = substream;
        if (!(chip->uartm & CS4281_MODE_OUTPUT)) {
                snd_cs4281_midi_reset(chip);
        } else {
                snd_cs4281_pokeBA0(chip, BA0_MIDCR, chip->midcr);
        }
        spin_unlock_irq(&chip->reg_lock);
        return 0;
}

static int snd_cs4281_midi_input_close(struct snd_rawmidi_substream *substream)
{
        struct cs4281 *chip = substream->rmidi->private_data;

        spin_lock_irq(&chip->reg_lock);
        chip->midcr &= ~(BA0_MIDCR_RXE | BA0_MIDCR_RIE);
        chip->midi_input = NULL;
        if (!(chip->uartm & CS4281_MODE_OUTPUT)) {
                snd_cs4281_midi_reset(chip);
        } else {
                snd_cs4281_pokeBA0(chip, BA0_MIDCR, chip->midcr);
        }
        chip->uartm &= ~CS4281_MODE_INPUT;
        spin_unlock_irq(&chip->reg_lock);
        return 0;
}

static int snd_cs4281_midi_output_open(struct snd_rawmidi_substream *substream)
{
        struct cs4281 *chip = substream->rmidi->private_data;

        spin_lock_irq(&chip->reg_lock);
        chip->uartm |= CS4281_MODE_OUTPUT;
        chip->midcr |= BA0_MIDCR_TXE;
        chip->midi_output = substream;
        if (!(chip->uartm & CS4281_MODE_INPUT)) {
                snd_cs4281_midi_reset(chip);
        } else {
                snd_cs4281_pokeBA0(chip, BA0_MIDCR, chip->midcr);
        }
        spin_unlock_irq(&chip->reg_lock);
        return 0;
}

static int snd_cs4281_midi_output_close(struct snd_rawmidi_substream *substream)
{
        struct cs4281 *chip = substream->rmidi->private_data;

        spin_lock_irq(&chip->reg_lock);
        chip->midcr &= ~(BA0_MIDCR_TXE | BA0_MIDCR_TIE);
        chip->midi_output = NULL;
        if (!(chip->uartm & CS4281_MODE_INPUT)) {
                snd_cs4281_midi_reset(chip);
        } else {
                snd_cs4281_pokeBA0(chip, BA0_MIDCR, chip->midcr);
        }
        chip->uartm &= ~CS4281_MODE_OUTPUT;
        spin_unlock_irq(&chip->reg_lock);
        return 0;
}

static void snd_cs4281_midi_input_trigger(struct snd_rawmidi_substream *substream, int up)
{
        unsigned long flags;
        struct cs4281 *chip = substream->rmidi->private_data;

        spin_lock_irqsave(&chip->reg_lock, flags);
        if (up) {
                if ((chip->midcr & BA0_MIDCR_RIE) == 0) {
                        chip->midcr |= BA0_MIDCR_RIE;
                        snd_cs4281_pokeBA0(chip, BA0_MIDCR, chip->midcr);
                }
        } else {
                if (chip->midcr & BA0_MIDCR_RIE) {
                        chip->midcr &= ~BA0_MIDCR_RIE;
                        snd_cs4281_pokeBA0(chip, BA0_MIDCR, chip->midcr);
                }
        }
        spin_unlock_irqrestore(&chip->reg_lock, flags);
}

static void snd_cs4281_midi_output_trigger(struct snd_rawmidi_substream *substream, int up)
{
        unsigned long flags;
        struct cs4281 *chip = substream->rmidi->private_data;
        unsigned char byte;

        spin_lock_irqsave(&chip->reg_lock, flags);
        if (up) {
                if ((chip->midcr & BA0_MIDCR_TIE) == 0) {
                        chip->midcr |= BA0_MIDCR_TIE;
                        /* fill UART FIFO buffer at first, and turn Tx interrupts only if necessary */
                        while ((chip->midcr & BA0_MIDCR_TIE) &&
                               (snd_cs4281_peekBA0(chip, BA0_MIDSR) & BA0_MIDSR_TBF) == 0) {
                                if (snd_rawmidi_transmit(substream, &byte, 1) != 1) {
                                        chip->midcr &= ~BA0_MIDCR_TIE;
                                } else {
                                        snd_cs4281_pokeBA0(chip, BA0_MIDWP, byte);
                                }
                        }
                        snd_cs4281_pokeBA0(chip, BA0_MIDCR, chip->midcr);
                }
        } else {
                if (chip->midcr & BA0_MIDCR_TIE) {
                        chip->midcr &= ~BA0_MIDCR_TIE;
                        snd_cs4281_pokeBA0(chip, BA0_MIDCR, chip->midcr);
                }
        }
        spin_unlock_irqrestore(&chip->reg_lock, flags);
}

static struct snd_rawmidi_ops snd_cs4281_midi_output =
{
        .open =         snd_cs4281_midi_output_open,
        .close =        snd_cs4281_midi_output_close,
        .trigger =      snd_cs4281_midi_output_trigger,
};

static struct snd_rawmidi_ops snd_cs4281_midi_input =
{
        .open =         snd_cs4281_midi_input_open,
        .close =        snd_cs4281_midi_input_close,
        .trigger =      snd_cs4281_midi_input_trigger,
};

static int snd_cs4281_midi(struct cs4281 *chip, int device,
                           struct snd_rawmidi **rrawmidi)
{
        struct snd_rawmidi *rmidi;
        int err;

        if (rrawmidi)
                *rrawmidi = NULL;
        if ((err = snd_rawmidi_new(chip->card, "CS4281", device, 1, 1, &rmidi)) < 0)
                return err;
        strcpy(rmidi->name, "CS4281");
        snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_cs4281_midi_output);
        snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_cs4281_midi_input);
        rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT | SNDRV_RAWMIDI_INFO_INPUT | SNDRV_RAWMIDI_INFO_DUPLEX;
        rmidi->private_data = chip;
        chip->rmidi = rmidi;
        if (rrawmidi)
                *rrawmidi = rmidi;
        return 0;
}

/*
 *  Interrupt handler
 */

static irqreturn_t snd_cs4281_interrupt(int irq, void *dev_id)
{
        struct cs4281 *chip = dev_id;
        unsigned int status, dma, val;
        struct cs4281_dma *cdma;

        if (chip == NULL)
                return IRQ_NONE;
        status = snd_cs4281_peekBA0(chip, BA0_HISR);
        if ((status & 0x7fffffff) == 0) {
                snd_cs4281_pokeBA0(chip, BA0_HICR, BA0_HICR_EOI);
                return IRQ_NONE;
        }

        if (status & (BA0_HISR_DMA(0)|BA0_HISR_DMA(1)|BA0_HISR_DMA(2)|BA0_HISR_DMA(3))) {
                for (dma = 0; dma < 4; dma++)
                        if (status & BA0_HISR_DMA(dma)) {
                                cdma = &chip->dma[dma];
                                spin_lock(&chip->reg_lock);
                                /* ack DMA IRQ */
                                val = snd_cs4281_peekBA0(chip, cdma->regHDSR);
                                /* workaround, sometimes CS4281 acknowledges */
                                /* end or middle transfer position twice */
                                cdma->frag++;
                                if ((val & BA0_HDSR_DHTC) && !(cdma->frag & 1)) {
                                        cdma->frag--;
                                        chip->spurious_dhtc_irq++;
                                        spin_unlock(&chip->reg_lock);
                                        continue;
                                }
                                if ((val & BA0_HDSR_DTC) && (cdma->frag & 1)) {
                                        cdma->frag--;
                                        chip->spurious_dtc_irq++;
                                        spin_unlock(&chip->reg_lock);
                                        continue;
                                }
                                spin_unlock(&chip->reg_lock);
                                snd_pcm_period_elapsed(cdma->substream);
                        }
        }

        if ((status & BA0_HISR_MIDI) && chip->rmidi) {
                unsigned char c;
                
                spin_lock(&chip->reg_lock);
                while ((snd_cs4281_peekBA0(chip, BA0_MIDSR) & BA0_MIDSR_RBE) == 0) {
                        c = snd_cs4281_peekBA0(chip, BA0_MIDRP);
                        if ((chip->midcr & BA0_MIDCR_RIE) == 0)
                                continue;
                        snd_rawmidi_receive(chip->midi_input, &c, 1);
                }
                while ((snd_cs4281_peekBA0(chip, BA0_MIDSR) & BA0_MIDSR_TBF) == 0) {
                        if ((chip->midcr & BA0_MIDCR_TIE) == 0)
                                break;
                        if (snd_rawmidi_transmit(chip->midi_output, &c, 1) != 1) {
                                chip->midcr &= ~BA0_MIDCR_TIE;
                                snd_cs4281_pokeBA0(chip, BA0_MIDCR, chip->midcr);
                                break;
                        }
                        snd_cs4281_pokeBA0(chip, BA0_MIDWP, c);
                }
                spin_unlock(&chip->reg_lock);
        }

        /* EOI to the PCI part... reenables interrupts */
        snd_cs4281_pokeBA0(chip, BA0_HICR, BA0_HICR_EOI);

        return IRQ_HANDLED;
}


/*
 * OPL3 command
 */
static void snd_cs4281_opl3_command(struct snd_opl3 *opl3, unsigned short cmd,
                                    unsigned char val)
{
        unsigned long flags;
        struct cs4281 *chip = opl3->private_data;
        void __iomem *port;

        if (cmd & OPL3_RIGHT)
                port = chip->ba0 + BA0_B1AP; /* right port */
        else
                port = chip->ba0 + BA0_B0AP; /* left port */

        spin_lock_irqsave(&opl3->reg_lock, flags);

        writel((unsigned int)cmd, port);
        udelay(10);

        writel((unsigned int)val, port + 4);
        udelay(30);

        spin_unlock_irqrestore(&opl3->reg_lock, flags);
}

static int snd_cs4281_probe(struct pci_dev *pci,
                            const struct pci_device_id *pci_id)
{
        static int dev;
        struct snd_card *card;
        struct cs4281 *chip;
        struct snd_opl3 *opl3;
        int err;

        if (dev >= SNDRV_CARDS)
                return -ENODEV;
        if (!enable[dev]) {
                dev++;
                return -ENOENT;
        }

        err = snd_card_new(&pci->dev, index[dev], id[dev], THIS_MODULE,
                           0, &card);
        if (err < 0)
                return err;

        if ((err = snd_cs4281_create(card, pci, &chip, dual_codec[dev])) < 0) {
                snd_card_free(card);
                return err;
        }
        card->private_data = chip;

        if ((err = snd_cs4281_mixer(chip)) < 0) {
                snd_card_free(card);
                return err;
        }
        if ((err = snd_cs4281_pcm(chip, 0, NULL)) < 0) {
                snd_card_free(card);
                return err;
        }
        if ((err = snd_cs4281_midi(chip, 0, NULL)) < 0) {
                snd_card_free(card);
                return err;
        }
        if ((err = snd_opl3_new(card, OPL3_HW_OPL3_CS4281, &opl3)) < 0) {
                snd_card_free(card);
                return err;
        }
        opl3->private_data = chip;
        opl3->command = snd_cs4281_opl3_command;
        snd_opl3_init(opl3);
        if ((err = snd_opl3_hwdep_new(opl3, 0, 1, NULL)) < 0) {
                snd_card_free(card);
                return err;
        }
        snd_cs4281_create_gameport(chip);
        strcpy(card->driver, "CS4281");
        strcpy(card->shortname, "Cirrus Logic CS4281");
        sprintf(card->longname, "%s at 0x%lx, irq %d",
                card->shortname,
                chip->ba0_addr,
                chip->irq);

        if ((err = snd_card_register(card)) < 0) {
                snd_card_free(card);
                return err;
        }

        pci_set_drvdata(pci, card);
        dev++;
        return 0;
}

static void snd_cs4281_remove(struct pci_dev *pci)
{
        snd_card_free(pci_get_drvdata(pci));
}

/*
 * Power Management
 */
#ifdef CONFIG_PM_SLEEP

static int saved_regs[SUSPEND_REGISTERS] = {
        BA0_JSCTL,
        BA0_GPIOR,
        BA0_SSCR,
        BA0_MIDCR,
        BA0_SRCSA,
        BA0_PASR,
        BA0_CASR,
        BA0_DACSR,
        BA0_ADCSR,

        BA0_FMLVC,
        BA0_FMRVC,
        BA0_PPLVC,
        BA0_PPRVC,
};

#define CLKCR1_CKRA                             0x00010000L

static int cs4281_suspend(struct device *dev)
{
        struct pci_dev *pci = to_pci_dev(dev);
        struct snd_card *card = dev_get_drvdata(dev);
        struct cs4281 *chip = card->private_data;
        u32 ulCLK;
        unsigned int i;

        snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
        snd_pcm_suspend_all(chip->pcm);

        snd_ac97_suspend(chip->ac97);
        snd_ac97_suspend(chip->ac97_secondary);

        ulCLK = snd_cs4281_peekBA0(chip, BA0_CLKCR1);
        ulCLK |= CLKCR1_CKRA;
        snd_cs4281_pokeBA0(chip, BA0_CLKCR1, ulCLK);

        /* Disable interrupts. */
        snd_cs4281_pokeBA0(chip, BA0_HICR, BA0_HICR_CHGM);

        /* remember the status registers */
        for (i = 0; i < ARRAY_SIZE(saved_regs); i++)
                if (saved_regs[i])
                        chip->suspend_regs[i] = snd_cs4281_peekBA0(chip, saved_regs[i]);

        /* Turn off the serial ports. */
        snd_cs4281_pokeBA0(chip, BA0_SERMC, 0);

        /* Power off FM, Joystick, AC link, */
        snd_cs4281_pokeBA0(chip, BA0_SSPM, 0);

        /* DLL off. */
        snd_cs4281_pokeBA0(chip, BA0_CLKCR1, 0);

        /* AC link off. */
        snd_cs4281_pokeBA0(chip, BA0_SPMC, 0);

        ulCLK = snd_cs4281_peekBA0(chip, BA0_CLKCR1);
        ulCLK &= ~CLKCR1_CKRA;
        snd_cs4281_pokeBA0(chip, BA0_CLKCR1, ulCLK);

        pci_disable_device(pci);
        pci_save_state(pci);
        pci_set_power_state(pci, PCI_D3hot);
        return 0;
}

static int cs4281_resume(struct device *dev)
{
        struct pci_dev *pci = to_pci_dev(dev);
        struct snd_card *card = dev_get_drvdata(dev);
        struct cs4281 *chip = card->private_data;
        unsigned int i;
        u32 ulCLK;

        pci_set_power_state(pci, PCI_D0);
        pci_restore_state(pci);
        if (pci_enable_device(pci) < 0) {
                dev_err(dev, "pci_enable_device failed, disabling device\n");
                snd_card_disconnect(card);
                return -EIO;
        }
        pci_set_master(pci);

        ulCLK = snd_cs4281_peekBA0(chip, BA0_CLKCR1);
        ulCLK |= CLKCR1_CKRA;
        snd_cs4281_pokeBA0(chip, BA0_CLKCR1, ulCLK);

        snd_cs4281_chip_init(chip);

        /* restore the status registers */
        for (i = 0; i < ARRAY_SIZE(saved_regs); i++)
                if (saved_regs[i])
                        snd_cs4281_pokeBA0(chip, saved_regs[i], chip->suspend_regs[i]);

        snd_ac97_resume(chip->ac97);
        snd_ac97_resume(chip->ac97_secondary);

        ulCLK = snd_cs4281_peekBA0(chip, BA0_CLKCR1);
        ulCLK &= ~CLKCR1_CKRA;
        snd_cs4281_pokeBA0(chip, BA0_CLKCR1, ulCLK);

        snd_power_change_state(card, SNDRV_CTL_POWER_D0);
        return 0;
}

static SIMPLE_DEV_PM_OPS(cs4281_pm, cs4281_suspend, cs4281_resume);
#define CS4281_PM_OPS   &cs4281_pm
#else
#define CS4281_PM_OPS   NULL
#endif /* CONFIG_PM_SLEEP */

static struct pci_driver cs4281_driver = {
        .name = KBUILD_MODNAME,
        .id_table = snd_cs4281_ids,
        .probe = snd_cs4281_probe,
        .remove = snd_cs4281_remove,
        .driver = {
                .pm = CS4281_PM_OPS,
        },
};
        
module_pci_driver(cs4281_driver);