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toaruos/modules/ac97.c

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/* vim: tabstop=4 shiftwidth=4 noexpandtab
* This file is part of ToaruOS and is released under the terms
* of the NCSA / University of Illinois License - see LICENSE.md
* Copyright (C) 2015 Michael Gerow
* Copyright (C) 2015 Kevin Lange
*
* Driver for the Intel AC'97.
*
* See <http://www.intel.com/design/chipsets/manuals/29802801.pdf>.
*/
#include <logging.h>
#include <mem.h>
#include <module.h>
#include <mod/snd.h>
#include <printf.h>
#include <pci.h>
#include <system.h>
/* Utility macros */
#define N_ELEMENTS(arr) (sizeof(arr) / sizeof((arr)[0]))
/* BARs! */
#define AC97_NAMBAR 0x10 /* Native Audio Mixer Base Address Register */
#define AC97_NABMBAR 0x14 /* Native Audio Bus Mastering Base Address Register */
/* Bus mastering IO port offsets */
#define AC97_PO_BDBAR 0x10 /* PCM out buffer descriptor BAR */
#define AC97_PO_CIV 0x14 /* PCM out current index value */
#define AC97_PO_LVI 0x15 /* PCM out last valid index */
#define AC97_PO_SR 0x16 /* PCM out status register */
#define AC97_PO_PICB 0x18 /* PCM out position in current buffer register */
#define AC97_PO_CR 0x1B /* PCM out control register */
/* Bus mastering misc */
/* Buffer descriptor list constants */
#define AC97_BDL_LEN 32 /* Buffer descriptor list length */
#define AC97_BDL_BUFFER_LEN 0x1000 /* Length of buffer in BDL */
#define AC97_CL_GET_LENGTH(cl) ((cl) & 0xFFFF) /* Decode length from cl */
#define AC97_CL_SET_LENGTH(cl, v) ((cl) = (v) & 0xFFFF) /* Encode length to cl */
#define AC97_CL_BUP (1 << 30) /* Buffer underrun policy in cl */
#define AC97_CL_IOC (1 << 31) /* Interrupt on completion flag in cl */
/* PCM out control register flags */
#define AC97_X_CR_RPBM (1 << 0) /* Run/pause bus master */
#define AC97_X_CR_RR (1 << 1) /* Reset registers */
#define AC97_X_CR_LVBIE (1 << 2) /* Last valid buffer interrupt enable */
#define AC97_X_CR_FEIE (1 << 3) /* FIFO error interrupt enable */
#define AC97_X_CR_IOCE (1 << 4) /* Interrupt on completion enable */
/* Status register flags */
#define AC97_X_SR_DCH (1 << 0) /* DMA controller halted */
#define AC97_X_SR_CELV (1 << 1) /* Current equals last valid */
#define AC97_X_SR_LVBCI (1 << 2) /* Last valid buffer completion interrupt */
#define AC97_X_SR_BCIS (1 << 3) /* Buffer completion interrupt status */
#define AC97_X_SR_FIFOE (1 << 3) /* FIFO error */
/* Mixer IO port offsets */
#define AC97_RESET 0x00
#define AC97_MASTER_VOLUME 0x02
#define AC97_AUX_OUT_VOLUME 0x04
#define AC97_MONO_VOLUME 0x06
#define AC97_PCM_OUT_VOLUME 0x18
/* snd values */
#define AC97_SND_NAME "Intel AC'97"
#define AC97_PLAYBACK_SPEED 48000
#define AC97_PLAYBACK_FORMAT SND_FORMAT_L16SLE
/* An entry in a buffer dscriptor list */
typedef struct {
uint32_t pointer; /* Pointer to buffer */
uint32_t cl; /* Control values and buffer length */
} __attribute__((packed)) ac97_bdl_entry_t;
typedef struct {
uint32_t pci_device;
uint16_t nabmbar; /* Native audio bus mastring BAR */
uint16_t nambar; /* Native audio mixing BAR */
size_t irq; /* This ac97's irq */
uint8_t lvi; /* The currently set last valid index */
ac97_bdl_entry_t * bdl; /* Buffer descriptor list */
uint16_t * bufs[AC97_BDL_LEN]; /* Virtual addresses for buffers in BDL */
uint32_t bdl_p;
} ac97_device_t;
static ac97_device_t _device;
#define AC97_KNOB_PCM_OUT (SND_KNOB_VENDOR + 0)
static snd_knob_t _knobs[] = {
{
"Master",
SND_KNOB_MASTER
},
{
"PCM Out",
SND_KNOB_VENDOR + 0
}
};
static int ac97_mixer_read(uint32_t knob_id, uint32_t *val);
static int ac97_mixer_write(uint32_t knob_id, uint32_t val);
static snd_device_t _snd = {
.name = AC97_SND_NAME,
.device = &_device,
.playback_speed = AC97_PLAYBACK_SPEED,
.playback_format = AC97_PLAYBACK_FORMAT,
.knobs = _knobs,
.num_knobs = N_ELEMENTS(_knobs),
.mixer_read = ac97_mixer_read,
.mixer_write = ac97_mixer_write,
};
/*
* This could be unnecessary if we instead allocate just two buffers and make
* the ac97 think there are more.
*/
static void find_ac97(uint32_t device, uint16_t vendorid, uint16_t deviceid, void * extra) {
ac97_device_t * ac97 = extra;
if ((vendorid == 0x8086) && (deviceid == 0x2415)) {
ac97->pci_device = device;
}
}
#define DIVISION 128
static int irq_handler(struct regs * regs) {
uint16_t sr = inports(_device.nabmbar + AC97_PO_SR);
if (sr & AC97_X_SR_LVBCI) {
outports(_device.nabmbar + AC97_PO_SR, AC97_X_SR_LVBCI);
} else if (sr & AC97_X_SR_BCIS) {
size_t f = (_device.lvi + 2) % AC97_BDL_LEN;
for (size_t i = 0; i < AC97_BDL_BUFFER_LEN * sizeof(*_device.bufs[0]); i += DIVISION) {
snd_request_buf(&_snd, DIVISION, (uint8_t *)_device.bufs[f] + i);
switch_task(1);
}
_device.lvi = (_device.lvi + 1) % AC97_BDL_LEN;
outportb(_device.nabmbar + AC97_PO_LVI, _device.lvi);
outports(_device.nabmbar + AC97_PO_SR, AC97_X_SR_BCIS);
} else if (sr & AC97_X_SR_FIFOE) {
outports(_device.nabmbar + AC97_PO_SR, AC97_X_SR_FIFOE);
} else {
return 0;
}
irq_ack(_device.irq);
return 1;
}
/* Currently we just assume right and left are the same */
static int ac97_mixer_read(uint32_t knob_id, uint32_t *val) {
switch (knob_id) {
case SND_KNOB_MASTER:
/* 6 bit value */
*val = (inports(_device.nambar + AC97_MASTER_VOLUME) & 0x3f) << (sizeof(*val) * 8 - 6);
*val = ~*val;
*val &= 0x3f << (sizeof(*val) * 8 - 6);
break;
case AC97_KNOB_PCM_OUT:
/* 5 bit value */
*val = (inports(_device.nambar + AC97_PCM_OUT_VOLUME) & 0x1f) << (sizeof(*val) * 8 - 5);
*val = ~*val;
*val &= 0x1f << (sizeof(*val) * 8 - 5);
break;
default:
return -1;
}
return 0;
}
static int ac97_mixer_write(uint32_t knob_id, uint32_t val) {
switch (knob_id) {
case SND_KNOB_MASTER: {
/* 0 is the highest volume */
val = ~val;
/* 6 bit value */
val >>= (sizeof(val) * 8 - 6);
uint16_t encoded = val | (val << 8);
outports(_device.nambar + AC97_MASTER_VOLUME, encoded);
break;
}
case AC97_KNOB_PCM_OUT: {
/* 0 is the highest volume */
val = ~val;
/* 5 bit value */
val >>= (sizeof(val) * 8 - 5);
uint16_t encoded = val | (val << 8);
outports(_device.nambar + AC97_PCM_OUT_VOLUME, encoded);
break;
}
default:
return -1;
}
return 0;
}
static int init(void) {
debug_print(NOTICE, "Initializing AC97");
pci_scan(&find_ac97, -1, &_device);
if (!_device.pci_device) {
return 1;
}
_device.nabmbar = pci_read_field(_device.pci_device, AC97_NABMBAR, 2) & ((uint32_t) -1) << 1;
_device.nambar = pci_read_field(_device.pci_device, PCI_BAR0, 4) & ((uint32_t) -1) << 1;
_device.irq = pci_read_field(_device.pci_device, PCI_INTERRUPT_LINE, 1);
irq_install_handler(_device.irq, irq_handler);
/* Enable all matter of interrupts */
outportb(_device.nabmbar + AC97_PO_CR, AC97_X_CR_FEIE | AC97_X_CR_IOCE);
/* Enable bus mastering and disable memory mapped space */
pci_write_field(_device.pci_device, PCI_COMMAND, 2, 0x5);
/* Put ourselves at a reasonable volume. */
uint16_t volume = 0x03 | (0x03 << 8);
outports(_device.nambar + AC97_MASTER_VOLUME, volume);
outports(_device.nambar + AC97_PCM_OUT_VOLUME, volume);
/* Allocate our BDL and our buffers */
_device.bdl = (void *)kmalloc_p(AC97_BDL_LEN * sizeof(*_device.bdl), &_device.bdl_p);
memset(_device.bdl, 0, AC97_BDL_LEN * sizeof(*_device.bdl));
for (int i = 0; i < AC97_BDL_LEN; i++) {
_device.bufs[i] = (uint16_t *)kmalloc_p(AC97_BDL_BUFFER_LEN * sizeof(*_device.bufs[0]),
&_device.bdl[i].pointer);
memset(_device.bufs[i], 0, AC97_BDL_BUFFER_LEN * sizeof(*_device.bufs[0]));
AC97_CL_SET_LENGTH(_device.bdl[i].cl, AC97_BDL_BUFFER_LEN);
/* Set all buffers to interrupt */
_device.bdl[i].cl |= AC97_CL_IOC;
}
/* Tell the ac97 where our BDL is */
outportl(_device.nabmbar + AC97_PO_BDBAR, _device.bdl_p);
/* Set the LVI to be the last index */
_device.lvi = 2;
outportb(_device.nabmbar + AC97_PO_LVI, _device.lvi);
snd_register(&_snd);
/* Start things playing */
outportb(_device.nabmbar + AC97_PO_CR, inportb(_device.nabmbar + AC97_PO_CR) | AC97_X_CR_RPBM);
debug_print(NOTICE, "AC97 initialized successfully");
return 0;
}
static int fini(void) {
snd_unregister(&_snd);
free(_device.bdl);
for (int i = 0; i < AC97_BDL_LEN; i++) {
free(_device.bufs[i]);
}
return 0;
}
MODULE_DEF(ac97, init, fini);
MODULE_DEPENDS(snd);
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