vwsnd.c

iis s3c2410-uda1341语音系统的 开发

/*
 * Sound driver for Silicon Graphics 320 and 540 Visual Workstations'
 * onboard audio.  See notes in ../../Documentation/sound/vwsnd .
 *
 * Copyright 1999 Silicon Graphics, Inc.  All rights reserved.
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#undef VWSND_DEBUG			/* define for debugging */

/*
 * XXX to do -
 *
 *	External sync.
 *	Rename swbuf, hwbuf, u&i, hwptr&swptr to something rational.
 *	Bug - if select() called before read(), pcm_setup() not called.
 *	Bug - output doesn't stop soon enough if process killed.
 */

/*
 * Things to test -
 *
 *	Will readv/writev work?  Write a test.
 *
 *	insmod/rmmod 100 million times.
 *
 *	Run I/O until int ptrs wrap around (roughly 6.2 hours @ DAT
 *	rate).
 *
 *	Concurrent threads banging on mixer simultaneously, both UP
 *	and SMP kernels.  Especially, watch for thread A changing
 *	OUTSRC while thread B changes gain -- both write to the same
 *	ad1843 register.
 *
 *	What happens if a client opens /dev/audio then forks?
 *	Do two procs have /dev/audio open?  Test.
 *
 *	Pump audio through the CD, MIC and line inputs and verify that
 *	they mix/mute into the output.
 *
 *	Apps:
 *		amp
 *		mpg123
 *		x11amp
 *		mxv
 *		kmedia
 *		esound
 *		need more input apps
 *
 *	Run tests while bombarding with signals.  setitimer(2) will do it...  */

/*
 * This driver is organized in nine sections.
 * The nine sections are:
 *
 *	debug stuff
 * 	low level lithium access
 *	high level lithium access
 *	AD1843 access
 *	PCM I/O
 *	audio driver
 *	mixer driver
 *	probe/attach/unload
 *	initialization and loadable kernel module interface
 *
 * That is roughly the order of increasing abstraction, so forward
 * dependencies are minimal.
 */

/*
 * Locking Notes
 *
 *	INC_USE_COUNT and DEC_USE_COUNT keep track of the number of
 *	open descriptors to this driver. They store it in vwsnd_use_count.
 * 	The global device list, vwsnd_dev_list,	is immutable when the IN_USE
 *	is true.
 *
 *	devc->open_lock is a semaphore that is used to enforce the
 *	single reader/single writer rule for /dev/audio.  The rule is
 *	that each device may have at most one reader and one writer.
 *	Open will block until the previous client has closed the
 *	device, unless O_NONBLOCK is specified.
 *
 *	The semaphore devc->io_sema serializes PCM I/O syscalls.  This
 *	is unnecessary in Linux 2.2, because the kernel lock
 *	serializes read, write, and ioctl globally, but it's there,
 *	ready for the brave, new post-kernel-lock world.
 *
 *	Locking between interrupt and baselevel is handled by the
 *	"lock" spinlock in vwsnd_port (one lock each for read and
 *	write).  Each half holds the lock just long enough to see what
 *	area it owns and update its pointers.  See pcm_output() and
 *	pcm_input() for most of the gory stuff.
 *
 *	devc->mix_sema serializes all mixer ioctls.  This is also
 *	redundant because of the kernel lock.
 *
 *	The lowest level lock is lith->lithium_lock.  It is a
 *	spinlock which is held during the two-register tango of
 *	reading/writing an AD1843 register.  See
 *	li_{read,write}_ad1843_reg().
 */

/*
 * Sample Format Notes
 *
 *	Lithium's DMA engine has two formats: 16-bit 2's complement
 *	and 8-bit unsigned .  16-bit transfers the data unmodified, 2
 *	bytes per sample.  8-bit unsigned transfers 1 byte per sample
 *	and XORs each byte with 0x80.  Lithium can input or output
 *	either mono or stereo in either format.
 *
 *	The AD1843 has four formats: 16-bit 2's complement, 8-bit
 *	unsigned, 8-bit mu-Law and 8-bit A-Law.
 *
 *	This driver supports five formats: AFMT_S8, AFMT_U8,
 *	AFMT_MU_LAW, AFMT_A_LAW, and AFMT_S16_LE.
 *
 *	For AFMT_U8 output, we keep the AD1843 in 16-bit mode, and
 *	rely on Lithium's XOR to translate between U8 and S8.
 *
 *	For AFMT_S8, AFMT_MU_LAW and AFMT_A_LAW output, we have to XOR
 *	the 0x80 bit in software to compensate for Lithium's XOR.
 *	This happens in pcm_copy_{in,out}().
 *
 * Changes:
 * 11-10-2000	Bartlomiej Zolnierkiewicz <[e-mail]>
 *		Added some __init/__exit
 */

#include <linux/module.h>
#include <linux/init.h>

#include <linux/sched.h>
#include <linux/semaphore.h>
#include <linux/stddef.h>
#include <linux/spinlock.h>
#include <linux/smp_lock.h>
#include <asm/fixmap.h>
#include <asm/cobalt.h>
#include <asm/semaphore.h>

#include "sound_config.h"

/*****************************************************************************/
/* debug stuff */

#ifdef VWSND_DEBUG

#include <linux/interrupt.h>		/* for in_interrupt() */

static int shut_up = 1;

/*
 * dbgassert - called when an assertion fails.
 */

static void dbgassert(const char *fcn, int line, const char *expr)
{
	if (in_interrupt())
		panic("ASSERTION FAILED IN INTERRUPT, %s:%s:%d %s\n",
		      __FILE__, fcn, line, expr);
	else {
		int x;
		printk(KERN_ERR "ASSERTION FAILED, %s:%s:%d %s\n",
		       __FILE__, fcn, line, expr);
		x = * (volatile int *) 0; /* force proc to exit */
	}
}

/*
 * Bunch of useful debug macros:
 *
 *	ASSERT	- print unless e nonzero (panic if in interrupt)
 *	DBGDO	- include arbitrary code if debugging
 *	DBGX	- debug print raw (w/o function name)
 *	DBGP	- debug print w/ function name
 *	DBGE	- debug print function entry
 *	DBGC	- debug print function call
 *	DBGR	- debug print function return
 *	DBGXV	- debug print raw when verbose
 *	DBGPV	- debug print when verbose
 *	DBGEV	- debug print function entry when verbose
 *	DBGRV	- debug print function return when verbose
 */

#define ASSERT(e)      ((e) ? (void) 0 : dbgassert(__FUNCTION__, __LINE__, #e))
#define DBGDO(x)            x
#define DBGX(fmt, args...)  (in_interrupt() ? 0 : printk(KERN_ERR fmt, ##args))
#define DBGP(fmt, args...)  (DBGX(__FUNCTION__ ": " fmt, ##args))
#define DBGE(fmt, args...)  (DBGX(__FUNCTION__ fmt, ##args))
#define DBGC(rtn)           (DBGP("calling %s\n", rtn))
#define DBGR()              (DBGP("returning\n"))
#define DBGXV(fmt, args...) (shut_up ? 0 : DBGX(fmt, ##args))
#define DBGPV(fmt, args...) (shut_up ? 0 : DBGP(fmt, ##args))
#define DBGEV(fmt, args...) (shut_up ? 0 : DBGE(fmt, ##args))
#define DBGCV(rtn)          (shut_up ? 0 : DBGC(rtn))
#define DBGRV()             (shut_up ? 0 : DBGR())

#else /* !VWSND_DEBUG */

#define ASSERT(e)           ((void) 0)
#define DBGDO(x)            /* don't */
#define DBGX(fmt, args...)  ((void) 0)
#define DBGP(fmt, args...)  ((void) 0)
#define DBGE(fmt, args...)  ((void) 0)
#define DBGC(rtn)           ((void) 0)
#define DBGR()              ((void) 0)
#define DBGPV(fmt, args...) ((void) 0)
#define DBGXV(fmt, args...) ((void) 0)
#define DBGEV(fmt, args...) ((void) 0)
#define DBGCV(rtn)          ((void) 0)
#define DBGRV()             ((void) 0)

#endif /* !VWSND_DEBUG */

/*****************************************************************************/
/* low level lithium access */

/*
 * We need to talk to Lithium registers on three pages.  Here are
 * the pages' offsets from the base address (0xFF001000).
 */

enum {
	LI_PAGE0_OFFSET = 0x01000 - 0x1000, /* FF001000 */
	LI_PAGE1_OFFSET = 0x0F000 - 0x1000, /* FF00F000 */
	LI_PAGE2_OFFSET = 0x10000 - 0x1000, /* FF010000 */
};

/* low-level lithium data */

typedef struct lithium {
	caddr_t		page0;		/* virtual addresses */
	caddr_t		page1;
	caddr_t		page2;
	spinlock_t	lock;		/* protects codec and UST/MSC access */
} lithium_t;

/*
 * li_create initializes the lithium_t structure and sets up vm mappings
 * to access the registers.
 * Returns 0 on success, -errno on failure.
 */

static int li_create(lithium_t *lith, unsigned long baseaddr)
{
	static void li_destroy(lithium_t *);

	lith->lock = SPIN_LOCK_UNLOCKED;
	lith->page0 = ioremap_nocache(baseaddr + LI_PAGE0_OFFSET, PAGE_SIZE);
	lith->page1 = ioremap_nocache(baseaddr + LI_PAGE1_OFFSET, PAGE_SIZE);
	lith->page2 = ioremap_nocache(baseaddr + LI_PAGE2_OFFSET, PAGE_SIZE);
	if (!lith->page0 || !lith->page1 || !lith->page2) {
		li_destroy(lith);
		return -ENOMEM;
	}
	return 0;
}

/*
 * li_destroy destroys the lithium_t structure and vm mappings.
 */

static void li_destroy(lithium_t *lith)
{
	if (lith->page0) {
		iounmap(lith->page0);
		lith->page0 = NULL;
	}
	if (lith->page1) {
		iounmap(lith->page1);
		lith->page1 = NULL;
	}
	if (lith->page2) {
		iounmap(lith->page2);
		lith->page2 = NULL;
	}
}

/*
 * basic register accessors - read/write long/byte
 */

static __inline__ unsigned long li_readl(lithium_t *lith, int off)
{
	return * (volatile unsigned long *) (lith->page0 + off);
}

static __inline__ unsigned char li_readb(lithium_t *lith, int off)
{
	return * (volatile unsigned char *) (lith->page0 + off);
}

static __inline__ void li_writel(lithium_t *lith, int off, unsigned long val)
{
	* (volatile unsigned long *) (lith->page0 + off) = val;
}

static __inline__ void li_writeb(lithium_t *lith, int off, unsigned char val)
{
	* (volatile unsigned char *) (lith->page0 + off) = val;
}

/*****************************************************************************/
/* High Level Lithium Access */

/*
 * Lithium DMA Notes
 *
 * Lithium has two dedicated DMA channels for audio.  They are known
 * as comm1 and comm2 (communication areas 1 and 2).  Comm1 is for
 * input, and comm2 is for output.  Each is controlled by three
 * registers: BASE (base address), CFG (config) and CCTL
 * (config/control).
 *
 * Each DMA channel points to a physically contiguous ring buffer in
 * main memory of up to 8 Kbytes.  (This driver always uses 8 Kb.)
 * There are three pointers into the ring buffer: read, write, and
 * trigger.  The pointers are 8 bits each.  Each pointer points to
 * 32-byte "chunks" of data.  The DMA engine moves 32 bytes at a time,
 * so there is no finer-granularity control.
 *
 * In comm1, the hardware updates the write ptr, and software updates
 * the read ptr.  In comm2, it's the opposite: hardware updates the
 * read ptr, and software updates the write ptr.  I designate the
 * hardware-updated ptr as the hwptr, and the software-updated ptr as
 * the swptr.
 *
 * The trigger ptr and trigger mask are used to trigger interrupts.
 * From the Lithium spec, section 5.6.8, revision of 12/15/1998:
 *
 *	Trigger Mask Value
 *
 *	A three bit wide field that represents a power of two mask
 *	that is used whenever the trigger pointer is compared to its
 *	respective read or write pointer.  A value of zero here
 *	implies a mask of 0xFF and a value of seven implies a mask
 *	0x01.  This value can be used to sub-divide the ring buffer
 *	into pie sections so that interrupts monitor the progress of
 *	hardware from section to section.
 *
 * My interpretation of that is, whenever the hw ptr is updated, it is
 * compared with the trigger ptr, and the result is masked by the
 * trigger mask.  (Actually, by the complement of the trigger mask.)
 * If the result is zero, an interrupt is triggered.  I.e., interrupt
 * if ((hwptr & ~mask) == (trptr & ~mask)).  The mask is formed from
 * the trigger register value as mask = (1 << (8 - tmreg)) - 1.
 *
 * In yet different words, setting tmreg to 0 causes an interrupt after
 * every 256 DMA chunks (8192 bytes) or once per traversal of the
 * ring buffer.  Setting it to 7 caues an interrupt every 2 DMA chunks
 * (64 bytes) or 128 times per traversal of the ring buffer.
 */

/* Lithium register offsets and bit definitions */

#define LI_HOST_CONTROLLER	0x000
# define LI_HC_RESET		 0x00008000
# define LI_HC_LINK_ENABLE	 0x00004000
# define LI_HC_LINK_FAILURE	 0x00000004
# define LI_HC_LINK_CODEC	 0x00000002
# define LI_HC_LINK_READY	 0x00000001

#define LI_INTR_STATUS		0x010
#define LI_INTR_MASK		0x014
# define LI_INTR_LINK_ERR	 0x00008000
# define LI_INTR_COMM2_TRIG	 0x00000008
# define LI_INTR_COMM2_UNDERFLOW 0x00000004
# define LI_INTR_COMM1_TRIG	 0x00000002
# define LI_INTR_COMM1_OVERFLOW  0x00000001

#define LI_CODEC_COMMAND	0x018
# define LI_CC_BUSY		 0x00008000
# define LI_CC_DIR		 0x00000080
#  define LI_CC_DIR_RD		  LI_CC_DIR
#  define LI_CC_DIR_WR		(!LI_CC_DIR)
# define LI_CC_ADDR_MASK	 0x0000007F

#define LI_CODEC_DATA		0x01C

#define LI_COMM1_BASE		0x100
#define LI_COMM1_CTL		0x104
# define LI_CCTL_RESET		 0x80000000
# define LI_CCTL_SIZE		 0x70000000
# define LI_CCTL_DMA_ENABLE	 0x08000000
# define LI_CCTL_TMASK		 0x07000000 /* trigger mask */
# define LI_CCTL_TPTR		 0x00FF0000 /* trigger pointer */
# define LI_CCTL_RPTR		 0x0000FF00
# define LI_CCTL_WPTR		 0x000000FF
#define LI_COMM1_CFG		0x108
# define LI_CCFG_LOCK		 0x00008000
# define LI_CCFG_SLOT		 0x00000070
# define LI_CCFG_DIRECTION	 0x00000008
#  define LI_CCFG_DIR_IN	(!LI_CCFG_DIRECTION)
#  define LI_CCFG_DIR_OUT	  LI_CCFG_DIRECTION
# define LI_CCFG_MODE		 0x00000004
#  define LI_CCFG_MODE_MONO	(!LI_CCFG_MODE)
#  define LI_CCFG_MODE_STEREO	  LI_CCFG_MODE
# define LI_CCFG_FORMAT		 0x00000003
#  define LI_CCFG_FMT_8BIT	  0x00000000
#  define LI_CCFG_FMT_16BIT	  0x00000001
#define LI_COMM2_BASE		0x10C
#define LI_COMM2_CTL		0x110
 /* bit definitions are the same as LI_COMM1_CTL */
#define LI_COMM2_CFG		0x114
 /* bit definitions are the same as LI_COMM1_CFG */

#define LI_UST_LOW		0x200	/* 64-bit Unadjusted System Time is */
#define LI_UST_HIGH		0x204	/* microseconds since boot */

#define LI_AUDIO1_UST		0x300	/* UST-MSC pairs */
#define LI_AUDIO1_MSC		0x304	/* MSC (Media Stream Counter) */
#define LI_AUDIO2_UST		0x308	/* counts samples actually */
#define LI_AUDIO2_MSC		0x30C	/* processed as of time UST */

/* 
 * Lithium's DMA engine operates on chunks of 32 bytes.  We call that
 * a DMACHUNK.
 */

#define DMACHUNK_SHIFT 5
#define DMACHUNK_SIZE (1 << DMACHUNK_SHIFT)
#define BYTES_TO_CHUNKS(bytes) ((bytes) >> DMACHUNK_SHIFT)
#define CHUNKS_TO_BYTES(chunks) ((chunks) << DMACHUNK_SHIFT)

/*
 * Two convenient macros to shift bitfields into/out of position.
 *
 * Observe that (mask & -mask) is (1 << low_set_bit_of(mask)).
 * As long as mask is constant, we trust the compiler will change the
 * multipy and divide into shifts.
 */

#define SHIFT_FIELD(val, mask) (((val) * ((mask) & -(mask))) & (mask))
#define UNSHIFT_FIELD(val, mask) (((val) & (mask)) / ((mask) & -(mask)))

/*