ARK-OS/arkos/kernel/sound/hda/core/controller.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * HD-audio controller helpers
 */

#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <sound/core.h>
#include <sound/hdaudio.h>
#include <sound/hda_register.h>
#include "local.h"

/* clear CORB read pointer properly */
static void azx_clear_corbrp(struct hdac_bus *bus)
{
	int timeout;

	for (timeout = 1000; timeout > 0; timeout--) {
		if (snd_hdac_chip_readw(bus, CORBRP) & AZX_CORBRP_RST)
			break;
		udelay(1);
	}
	if (timeout <= 0)
		dev_err(bus->dev, "CORB reset timeout#1, CORBRP = %d\n",
			snd_hdac_chip_readw(bus, CORBRP));

	snd_hdac_chip_writew(bus, CORBRP, 0);
	for (timeout = 1000; timeout > 0; timeout--) {
		if (snd_hdac_chip_readw(bus, CORBRP) == 0)
			break;
		udelay(1);
	}
	if (timeout <= 0)
		dev_err(bus->dev, "CORB reset timeout#2, CORBRP = %d\n",
			snd_hdac_chip_readw(bus, CORBRP));
}

/**
 * snd_hdac_bus_init_cmd_io - set up CORB/RIRB buffers
 * @bus: HD-audio core bus
 */
void snd_hdac_bus_init_cmd_io(struct hdac_bus *bus)
{
	WARN_ON_ONCE(!bus->rb.area);

	guard(spinlock_irq)(&bus->reg_lock);
	/* CORB set up */
	bus->corb.addr = bus->rb.addr;
	bus->corb.buf = (__le32 *)bus->rb.area;
	snd_hdac_chip_writel(bus, CORBLBASE, (u32)(bus->corb.addr + bus->addr_offset));
	snd_hdac_chip_writel(bus, CORBUBASE, upper_32_bits(bus->corb.addr + bus->addr_offset));

	/* set the corb size to 256 entries (ULI requires explicitly) */
	snd_hdac_chip_writeb(bus, CORBSIZE, 0x02);
	/* set the corb write pointer to 0 */
	snd_hdac_chip_writew(bus, CORBWP, 0);

	/* reset the corb hw read pointer */
	snd_hdac_chip_writew(bus, CORBRP, AZX_CORBRP_RST);
	if (!bus->corbrp_self_clear)
		azx_clear_corbrp(bus);

	/* enable corb dma */
	if (!bus->use_pio_for_commands)
		snd_hdac_chip_writeb(bus, CORBCTL, AZX_CORBCTL_RUN);

	/* RIRB set up */
	bus->rirb.addr = bus->rb.addr + 2048;
	bus->rirb.buf = (__le32 *)(bus->rb.area + 2048);
	bus->rirb.wp = bus->rirb.rp = 0;
	memset(bus->rirb.cmds, 0, sizeof(bus->rirb.cmds));
	snd_hdac_chip_writel(bus, RIRBLBASE, (u32)(bus->rirb.addr + bus->addr_offset));
	snd_hdac_chip_writel(bus, RIRBUBASE, upper_32_bits(bus->rirb.addr + bus->addr_offset));

	/* set the rirb size to 256 entries (ULI requires explicitly) */
	snd_hdac_chip_writeb(bus, RIRBSIZE, 0x02);
	/* reset the rirb hw write pointer */
	snd_hdac_chip_writew(bus, RIRBWP, AZX_RIRBWP_RST);
	/* set N=1, get RIRB response interrupt for new entry */
	snd_hdac_chip_writew(bus, RINTCNT, 1);
	/* enable rirb dma and response irq */
	if (bus->not_use_interrupts)
		snd_hdac_chip_writeb(bus, RIRBCTL, AZX_RBCTL_DMA_EN);
	else
		snd_hdac_chip_writeb(bus, RIRBCTL, AZX_RBCTL_DMA_EN | AZX_RBCTL_IRQ_EN);
	/* Accept unsolicited responses */
	snd_hdac_chip_updatel(bus, GCTL, AZX_GCTL_UNSOL, AZX_GCTL_UNSOL);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_init_cmd_io);

/* wait for cmd dmas till they are stopped */
static void hdac_wait_for_cmd_dmas(struct hdac_bus *bus)
{
	unsigned long timeout;

	timeout = jiffies + msecs_to_jiffies(100);
	while ((snd_hdac_chip_readb(bus, RIRBCTL) & AZX_RBCTL_DMA_EN)
		&& time_before(jiffies, timeout))
		udelay(10);

	timeout = jiffies + msecs_to_jiffies(100);
	while ((snd_hdac_chip_readb(bus, CORBCTL) & AZX_CORBCTL_RUN)
		&& time_before(jiffies, timeout))
		udelay(10);
}

/**
 * snd_hdac_bus_stop_cmd_io - clean up CORB/RIRB buffers
 * @bus: HD-audio core bus
 */
void snd_hdac_bus_stop_cmd_io(struct hdac_bus *bus)
{
	scoped_guard(spinlock_irq, &bus->reg_lock) {
		/* disable ringbuffer DMAs */
		snd_hdac_chip_writeb(bus, RIRBCTL, 0);
		snd_hdac_chip_writeb(bus, CORBCTL, 0);
	}

	hdac_wait_for_cmd_dmas(bus);

	guard(spinlock_irq)(&bus->reg_lock);
	/* disable unsolicited responses */
	snd_hdac_chip_updatel(bus, GCTL, AZX_GCTL_UNSOL, 0);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_stop_cmd_io);

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

	if (snd_BUG_ON(addr >= HDA_MAX_CODECS))
		addr = 0;
	return addr;
}

/* receive an Immediate Response with PIO */
static int snd_hdac_bus_wait_for_pio_response(struct hdac_bus *bus,
					      unsigned int addr)
{
	int timeout = 50;

	while (timeout--) {
		/* check IRV bit */
		if (snd_hdac_chip_readw(bus, IRS) & AZX_IRS_VALID) {
			/* reuse rirb.res as the response return value */
			bus->rirb.res[addr] = snd_hdac_chip_readl(bus, IR);
			return 0;
		}
		udelay(1);
	}

	dev_dbg_ratelimited(bus->dev, "get_response_pio timeout: IRS=%#x\n",
			    snd_hdac_chip_readw(bus, IRS));

	bus->rirb.res[addr] = -1;

	return -EIO;
}

/**
 * snd_hdac_bus_send_cmd_pio - send a command verb via Immediate Command
 * @bus: HD-audio core bus
 * @val: encoded verb value to send
 *
 * Returns zero for success or a negative error code.
 */
static int snd_hdac_bus_send_cmd_pio(struct hdac_bus *bus, unsigned int val)
{
	unsigned int addr = azx_command_addr(val);
	int timeout = 50;

	guard(spinlock_irq)(&bus->reg_lock);

	while (timeout--) {
		/* check ICB bit */
		if (!((snd_hdac_chip_readw(bus, IRS) & AZX_IRS_BUSY))) {
			/* Clear IRV bit */
			snd_hdac_chip_updatew(bus, IRS, AZX_IRS_VALID, AZX_IRS_VALID);
			snd_hdac_chip_writel(bus, IC, val);
			/* Set ICB bit */
			snd_hdac_chip_updatew(bus, IRS, AZX_IRS_BUSY, AZX_IRS_BUSY);

			return snd_hdac_bus_wait_for_pio_response(bus, addr);
		}
		udelay(1);
	}

	dev_dbg_ratelimited(bus->dev, "send_cmd_pio timeout: IRS=%#x, val=%#x\n",
			    snd_hdac_chip_readw(bus, IRS), val);

	return -EIO;
}

/**
 * snd_hdac_bus_get_response_pio - receive a response via Immediate Response
 * @bus: HD-audio core bus
 * @addr: codec address
 * @res: pointer to store the value, NULL when not needed
 *
 * Returns zero if a value is read, or a negative error code.
 */
static int snd_hdac_bus_get_response_pio(struct hdac_bus *bus,
					 unsigned int addr, unsigned int *res)
{
	if (res)
		*res = bus->rirb.res[addr];

	return 0;
}

/**
 * snd_hdac_bus_send_cmd_corb - send a command verb via CORB
 * @bus: HD-audio core bus
 * @val: encoded verb value to send
 *
 * Returns zero for success or a negative error code.
 */
static int snd_hdac_bus_send_cmd_corb(struct hdac_bus *bus, unsigned int val)
{
	unsigned int addr = azx_command_addr(val);
	unsigned int wp, rp;

	guard(spinlock_irq)(&bus->reg_lock);

	bus->last_cmd[azx_command_addr(val)] = val;

	/* add command to corb */
	wp = snd_hdac_chip_readw(bus, CORBWP);
	if (wp == 0xffff) {
		/* something wrong, controller likely turned to D3 */
		return -EIO;
	}
	wp++;
	wp %= AZX_MAX_CORB_ENTRIES;

	rp = snd_hdac_chip_readw(bus, CORBRP);
	if (wp == rp) {
		/* oops, it's full */
		return -EAGAIN;
	}

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

	return 0;
}

#define AZX_RIRB_EX_UNSOL_EV	(1<<4)

/**
 * snd_hdac_bus_update_rirb - retrieve RIRB entries
 * @bus: HD-audio core bus
 *
 * Usually called from interrupt handler.
 * The caller needs bus->reg_lock spinlock before calling this.
 */
void snd_hdac_bus_update_rirb(struct hdac_bus *bus)
{
	unsigned int rp, wp;
	unsigned int addr;
	u32 res, res_ex;

	wp = snd_hdac_chip_readw(bus, RIRBWP);
	if (wp == 0xffff) {
		/* something wrong, controller likely turned to D3 */
		return;
	}

	if (wp == bus->rirb.wp)
		return;
	bus->rirb.wp = wp;

	while (bus->rirb.rp != wp) {
		bus->rirb.rp++;
		bus->rirb.rp %= AZX_MAX_RIRB_ENTRIES;

		rp = bus->rirb.rp << 1; /* an RIRB entry is 8-bytes */
		res_ex = le32_to_cpu(bus->rirb.buf[rp + 1]);
		res = le32_to_cpu(bus->rirb.buf[rp]);
		addr = res_ex & 0xf;
		if (addr >= HDA_MAX_CODECS) {
			dev_err(bus->dev,
				"spurious response %#x:%#x, rp = %d, wp = %d",
				res, res_ex, bus->rirb.rp, wp);
			snd_BUG();
		} else if (res_ex & AZX_RIRB_EX_UNSOL_EV)
			snd_hdac_bus_queue_event(bus, res, res_ex);
		else if (bus->rirb.cmds[addr]) {
			bus->rirb.res[addr] = res;
			bus->rirb.cmds[addr]--;
			if (!bus->rirb.cmds[addr] &&
			    waitqueue_active(&bus->rirb_wq))
				wake_up(&bus->rirb_wq);
		} else {
			dev_err_ratelimited(bus->dev,
				"spurious response %#x:%#x, last cmd=%#08x\n",
				res, res_ex, bus->last_cmd[addr]);
		}
	}
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_update_rirb);

/**
 * snd_hdac_bus_get_response_rirb - receive a response via RIRB
 * @bus: HD-audio core bus
 * @addr: codec address
 * @res: pointer to store the value, NULL when not needed
 *
 * Returns zero if a value is read, or a negative error code.
 */
static int snd_hdac_bus_get_response_rirb(struct hdac_bus *bus,
					  unsigned int addr, unsigned int *res)
{
	unsigned long timeout;
	unsigned long loopcounter;
	wait_queue_entry_t wait;
	bool warned = false;

	init_wait_entry(&wait, 0);
	timeout = jiffies + msecs_to_jiffies(1000);

	for (loopcounter = 0;; loopcounter++) {
		scoped_guard(spinlock_irq, &bus->reg_lock) {
			if (!bus->polling_mode)
				prepare_to_wait(&bus->rirb_wq, &wait,
						TASK_UNINTERRUPTIBLE);
			if (bus->polling_mode)
				snd_hdac_bus_update_rirb(bus);
			if (!bus->rirb.cmds[addr]) {
				if (res)
					*res = bus->rirb.res[addr]; /* the last value */
				if (!bus->polling_mode)
					finish_wait(&bus->rirb_wq, &wait);
				return 0;
			}
		}
		if (time_after(jiffies, timeout))
			break;
#define LOOP_COUNT_MAX	3000
		if (!bus->polling_mode) {
			schedule_timeout(msecs_to_jiffies(2));
		} else if (bus->needs_damn_long_delay ||
			   loopcounter > LOOP_COUNT_MAX) {
			if (loopcounter > LOOP_COUNT_MAX && !warned) {
				dev_dbg_ratelimited(bus->dev,
						    "too slow response, last cmd=%#08x\n",
						    bus->last_cmd[addr]);
				warned = true;
			}
			msleep(2); /* temporary workaround */
		} else {
			udelay(10);
			cond_resched();
		}
	}

	if (!bus->polling_mode)
		finish_wait(&bus->rirb_wq, &wait);

	return -EIO;
}

/**
 * snd_hdac_bus_send_cmd - send a command verb via CORB or PIO
 * @bus: HD-audio core bus
 * @val: encoded verb value to send
 *
 * Returns zero for success or a negative error code.
 */
int snd_hdac_bus_send_cmd(struct hdac_bus *bus, unsigned int val)
{
	if (bus->use_pio_for_commands)
		return snd_hdac_bus_send_cmd_pio(bus, val);

	return snd_hdac_bus_send_cmd_corb(bus, val);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_send_cmd);

/**
 * snd_hdac_bus_get_response - receive a response via RIRB or PIO
 * @bus: HD-audio core bus
 * @addr: codec address
 * @res: pointer to store the value, NULL when not needed
 *
 * Returns zero if a value is read, or a negative error code.
 */
int snd_hdac_bus_get_response(struct hdac_bus *bus, unsigned int addr,
			      unsigned int *res)
{
	if (bus->use_pio_for_commands)
		return snd_hdac_bus_get_response_pio(bus, addr, res);

	return snd_hdac_bus_get_response_rirb(bus, addr, res);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_get_response);

#define HDAC_MAX_CAPS 10
/**
 * snd_hdac_bus_parse_capabilities - parse capability structure
 * @bus: the pointer to bus object
 *
 * Returns 0 if successful, or a negative error code.
 */
int snd_hdac_bus_parse_capabilities(struct hdac_bus *bus)
{
	unsigned int cur_cap;
	unsigned int offset;
	unsigned int counter = 0;

	offset = snd_hdac_chip_readw(bus, LLCH);

	/* Lets walk the linked capabilities list */
	do {
		cur_cap = _snd_hdac_chip_readl(bus, offset);

		dev_dbg(bus->dev, "Capability version: 0x%x\n",
			(cur_cap & AZX_CAP_HDR_VER_MASK) >> AZX_CAP_HDR_VER_OFF);

		dev_dbg(bus->dev, "HDA capability ID: 0x%x\n",
			(cur_cap & AZX_CAP_HDR_ID_MASK) >> AZX_CAP_HDR_ID_OFF);

		if (cur_cap == -1) {
			dev_dbg(bus->dev, "Invalid capability reg read\n");
			break;
		}

		switch ((cur_cap & AZX_CAP_HDR_ID_MASK) >> AZX_CAP_HDR_ID_OFF) {
		case AZX_ML_CAP_ID:
			dev_dbg(bus->dev, "Found ML capability\n");
			bus->mlcap = bus->remap_addr + offset;
			break;

		case AZX_GTS_CAP_ID:
			dev_dbg(bus->dev, "Found GTS capability offset=%x\n", offset);
			bus->gtscap = bus->remap_addr + offset;
			break;

		case AZX_PP_CAP_ID:
			/* PP capability found, the Audio DSP is present */
			dev_dbg(bus->dev, "Found PP capability offset=%x\n", offset);
			bus->ppcap = bus->remap_addr + offset;
			break;

		case AZX_SPB_CAP_ID:
			/* SPIB capability found, handler function */
			dev_dbg(bus->dev, "Found SPB capability\n");
			bus->spbcap = bus->remap_addr + offset;
			break;

		case AZX_DRSM_CAP_ID:
			/* DMA resume  capability found, handler function */
			dev_dbg(bus->dev, "Found DRSM capability\n");
			bus->drsmcap = bus->remap_addr + offset;
			break;

		default:
			dev_err(bus->dev, "Unknown capability %d\n", cur_cap);
			cur_cap = 0;
			break;
		}

		counter++;

		if (counter > HDAC_MAX_CAPS) {
			dev_err(bus->dev, "We exceeded HDAC capabilities!!!\n");
			break;
		}

		/* read the offset of next capability */
		offset = cur_cap & AZX_CAP_HDR_NXT_PTR_MASK;

	} while (offset);

	return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_parse_capabilities);

/*
 * Lowlevel interface
 */

/**
 * snd_hdac_bus_enter_link_reset - enter link reset
 * @bus: HD-audio core bus
 *
 * Enter to the link reset state.
 */
void snd_hdac_bus_enter_link_reset(struct hdac_bus *bus)
{
	unsigned long timeout;

	/* reset controller */
	snd_hdac_chip_updatel(bus, GCTL, AZX_GCTL_RESET, 0);

	timeout = jiffies + msecs_to_jiffies(100);
	while ((snd_hdac_chip_readb(bus, GCTL) & AZX_GCTL_RESET) &&
	       time_before(jiffies, timeout))
		usleep_range(500, 1000);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_enter_link_reset);

/**
 * snd_hdac_bus_exit_link_reset - exit link reset
 * @bus: HD-audio core bus
 *
 * Exit from the link reset state.
 */
void snd_hdac_bus_exit_link_reset(struct hdac_bus *bus)
{
	unsigned long timeout;

	snd_hdac_chip_updateb(bus, GCTL, AZX_GCTL_RESET, AZX_GCTL_RESET);

	timeout = jiffies + msecs_to_jiffies(100);
	while (!snd_hdac_chip_readb(bus, GCTL) && time_before(jiffies, timeout))
		usleep_range(500, 1000);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_exit_link_reset);

/* reset codec link */
int snd_hdac_bus_reset_link(struct hdac_bus *bus, bool full_reset)
{
	if (!full_reset)
		goto skip_reset;

	/* clear STATESTS if not in reset */
	if (snd_hdac_chip_readb(bus, GCTL) & AZX_GCTL_RESET)
		snd_hdac_chip_writew(bus, STATESTS, STATESTS_INT_MASK);

	/* reset controller */
	snd_hdac_bus_enter_link_reset(bus);

	/* delay for >= 100us for codec PLL to settle per spec
	 * Rev 0.9 section 5.5.1
	 */
	usleep_range(500, 1000);

	/* Bring controller out of reset */
	snd_hdac_bus_exit_link_reset(bus);

	/* Brent Chartrand said to wait >= 540us for codecs to initialize */
	usleep_range(1000, 1200);

 skip_reset:
	/* check to see if controller is ready */
	if (!snd_hdac_chip_readb(bus, GCTL)) {
		dev_dbg(bus->dev, "controller not ready!\n");
		return -EBUSY;
	}

	/* detect codecs */
	if (!bus->codec_mask) {
		bus->codec_mask = snd_hdac_chip_readw(bus, STATESTS);
		dev_dbg(bus->dev, "codec_mask = 0x%lx\n", bus->codec_mask);
	}

	return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_reset_link);

/* enable interrupts */
static void azx_int_enable(struct hdac_bus *bus)
{
	/* enable controller CIE and GIE */
	snd_hdac_chip_updatel(bus, INTCTL,
			      AZX_INT_CTRL_EN | AZX_INT_GLOBAL_EN,
			      AZX_INT_CTRL_EN | AZX_INT_GLOBAL_EN);
}

/* disable interrupts */
static void azx_int_disable(struct hdac_bus *bus)
{
	struct hdac_stream *azx_dev;

	/* disable interrupts in stream descriptor */
	list_for_each_entry(azx_dev, &bus->stream_list, list)
		snd_hdac_stream_updateb(azx_dev, SD_CTL, SD_INT_MASK, 0);

	/* disable SIE for all streams & disable controller CIE and GIE */
	snd_hdac_chip_writel(bus, INTCTL, 0);
}

/* clear interrupts */
static void azx_int_clear(struct hdac_bus *bus)
{
	struct hdac_stream *azx_dev;

	/* clear stream status */
	list_for_each_entry(azx_dev, &bus->stream_list, list)
		snd_hdac_stream_writeb(azx_dev, SD_STS, SD_INT_MASK);

	/* clear STATESTS */
	snd_hdac_chip_writew(bus, STATESTS, STATESTS_INT_MASK);

	/* clear rirb status */
	snd_hdac_chip_writeb(bus, RIRBSTS, RIRB_INT_MASK);

	/* clear int status */
	snd_hdac_chip_writel(bus, INTSTS, AZX_INT_CTRL_EN | AZX_INT_ALL_STREAM);
}

/**
 * snd_hdac_bus_init_chip - reset and start the controller registers
 * @bus: HD-audio core bus
 * @full_reset: Do full reset
 */
bool snd_hdac_bus_init_chip(struct hdac_bus *bus, bool full_reset)
{
	if (bus->chip_init)
		return false;

	/* reset controller */
	snd_hdac_bus_reset_link(bus, full_reset);

	/* clear interrupts */
	azx_int_clear(bus);

	/* initialize the codec command I/O */
	snd_hdac_bus_init_cmd_io(bus);

	/* enable interrupts after CORB/RIRB buffers are initialized above */
	azx_int_enable(bus);

	/* program the position buffer */
	if (bus->use_posbuf && bus->posbuf.addr) {
		snd_hdac_chip_writel(bus, DPLBASE, (u32)(bus->posbuf.addr + bus->addr_offset));
		snd_hdac_chip_writel(bus, DPUBASE, upper_32_bits(bus->posbuf.addr + bus->addr_offset));
	}

	bus->chip_init = true;

	return true;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_init_chip);

/**
 * snd_hdac_bus_stop_chip - disable the whole IRQ and I/Os
 * @bus: HD-audio core bus
 */
void snd_hdac_bus_stop_chip(struct hdac_bus *bus)
{
	if (!bus->chip_init)
		return;

	/* disable interrupts */
	azx_int_disable(bus);
	azx_int_clear(bus);

	/* disable CORB/RIRB */
	snd_hdac_bus_stop_cmd_io(bus);

	/* disable position buffer */
	if (bus->posbuf.addr) {
		snd_hdac_chip_writel(bus, DPLBASE, 0);
		snd_hdac_chip_writel(bus, DPUBASE, 0);
	}

	bus->chip_init = false;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_stop_chip);

/**
 * snd_hdac_bus_handle_stream_irq - interrupt handler for streams
 * @bus: HD-audio core bus
 * @status: INTSTS register value
 * @ack: callback to be called for woken streams
 *
 * Returns the bits of handled streams, or zero if no stream is handled.
 */
int snd_hdac_bus_handle_stream_irq(struct hdac_bus *bus, unsigned int status,
				    void (*ack)(struct hdac_bus *,
						struct hdac_stream *))
{
	struct hdac_stream *azx_dev;
	u8 sd_status;
	int handled = 0;

	list_for_each_entry(azx_dev, &bus->stream_list, list) {
		if (status & azx_dev->sd_int_sta_mask) {
			sd_status = snd_hdac_stream_readb(azx_dev, SD_STS);
			snd_hdac_stream_writeb(azx_dev, SD_STS, SD_INT_MASK);
			handled |= 1 << azx_dev->index;
			if ((!azx_dev->substream && !azx_dev->cstream) ||
			    !azx_dev->running || !(sd_status & SD_INT_COMPLETE))
				continue;
			if (ack)
				ack(bus, azx_dev);
		}
	}
	return handled;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_handle_stream_irq);

/**
 * snd_hdac_bus_alloc_stream_pages - allocate BDL and other buffers
 * @bus: HD-audio core bus
 *
 * Call this after assigning the all streams.
 * Returns zero for success, or a negative error code.
 */
int snd_hdac_bus_alloc_stream_pages(struct hdac_bus *bus)
{
	struct hdac_stream *s;
	int num_streams = 0;
	int dma_type = bus->dma_type ? bus->dma_type : SNDRV_DMA_TYPE_DEV;
	int err;

	list_for_each_entry(s, &bus->stream_list, list) {
		/* allocate memory for the BDL for each stream */
		err = snd_dma_alloc_pages(dma_type, bus->dev,
					  BDL_SIZE, &s->bdl);
		num_streams++;
		if (err < 0)
			return -ENOMEM;
	}

	if (WARN_ON(!num_streams))
		return -EINVAL;
	/* allocate memory for the position buffer */
	err = snd_dma_alloc_pages(dma_type, bus->dev,
				  num_streams * 8, &bus->posbuf);
	if (err < 0)
		return -ENOMEM;
	list_for_each_entry(s, &bus->stream_list, list)
		s->posbuf = (__le32 *)(bus->posbuf.area + s->index * 8);

	/* single page (at least 4096 bytes) must suffice for both ringbuffes */
	return snd_dma_alloc_pages(dma_type, bus->dev, PAGE_SIZE, &bus->rb);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_alloc_stream_pages);

/**
 * snd_hdac_bus_free_stream_pages - release BDL and other buffers
 * @bus: HD-audio core bus
 */
void snd_hdac_bus_free_stream_pages(struct hdac_bus *bus)
{
	struct hdac_stream *s;

	list_for_each_entry(s, &bus->stream_list, list) {
		if (s->bdl.area)
			snd_dma_free_pages(&s->bdl);
	}

	if (bus->rb.area)
		snd_dma_free_pages(&bus->rb);
	if (bus->posbuf.area)
		snd_dma_free_pages(&bus->posbuf);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_free_stream_pages);

/**
 * snd_hdac_bus_link_power - power up/down codec link
 * @codec: HD-audio device
 * @enable: whether to power-up the link
 */
void snd_hdac_bus_link_power(struct hdac_device *codec, bool enable)
{
	if (enable)
		set_bit(codec->addr, &codec->bus->codec_powered);
	else
		clear_bit(codec->addr, &codec->bus->codec_powered);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_link_power);