/*
 * 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>

/* 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)
{
        spin_lock_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);
        snd_hdac_chip_writel(bus, CORBUBASE, upper_32_bits(bus->corb.addr));

        /* 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 */
        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);
        snd_hdac_chip_writel(bus, RIRBUBASE, upper_32_bits(bus->rirb.addr));

        /* 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 */
        snd_hdac_chip_writeb(bus, RIRBCTL, AZX_RBCTL_DMA_EN | AZX_RBCTL_IRQ_EN);
        spin_unlock_irq(&bus->reg_lock);
}
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)
{
        spin_lock_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);
        /* disable unsolicited responses */
        snd_hdac_chip_updatel(bus, GCTL, AZX_GCTL_UNSOL, 0);
        spin_unlock_irq(&bus->reg_lock);
}
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;
}

/**
 * snd_hdac_bus_send_cmd - 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.
 */
int snd_hdac_bus_send_cmd(struct hdac_bus *bus, unsigned int val)
{
        unsigned int addr = azx_command_addr(val);
        unsigned int wp, rp;

        spin_lock_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 */
                spin_unlock_irq(&bus->reg_lock);
                return -EIO;
        }
        wp++;
        wp %= AZX_MAX_CORB_ENTRIES;

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

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

        spin_unlock_irq(&bus->reg_lock);

        return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_send_cmd);

#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.
 */
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]--;
                } 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 - 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.
 */
int snd_hdac_bus_get_response(struct hdac_bus *bus, unsigned int addr,
                              unsigned int *res)
{
        unsigned long timeout;
        unsigned long loopcounter;

        timeout = jiffies + msecs_to_jiffies(1000);

        for (loopcounter = 0;; loopcounter++) {
                spin_lock_irq(&bus->reg_lock);
                if (!bus->rirb.cmds[addr]) {
                        if (res)
                                *res = bus->rirb.res[addr]; /* the last value */
                        spin_unlock_irq(&bus->reg_lock);
                        return 0;
                }
                spin_unlock_irq(&bus->reg_lock);
                if (time_after(jiffies, timeout))
                        break;
                if (loopcounter > 3000)
                        msleep(2); /* temporary workaround */
                else {
                        udelay(10);
                        cond_resched();
                }
        }

        return -EIO;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_get_response);

/*
 * 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, 0, 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 */
static int azx_reset(struct hdac_bus *bus, bool full_reset)
{
        if (!full_reset)
                goto skip_reset;

        /* clear STATESTS */
        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, "azx_reset: controller not ready!\n");
                return -EBUSY;
        }

        /* Accept unsolicited responses */
        snd_hdac_chip_updatel(bus, GCTL, 0, AZX_GCTL_UNSOL);

        /* 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;
}

/* enable interrupts */
static void azx_int_enable(struct hdac_bus *bus)
{
        /* enable controller CIE and GIE */
        snd_hdac_chip_updatel(bus, INTCTL, 0, 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 */
        snd_hdac_chip_writeb(bus, INTCTL, 0);

        /* disable controller CIE and GIE */
        snd_hdac_chip_updatel(bus, INTCTL, AZX_INT_CTRL_EN | AZX_INT_GLOBAL_EN, 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 */
        azx_reset(bus, full_reset);

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

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

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

        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
 * @ask: 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->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 err;

        list_for_each_entry(s, &bus->stream_list, list) {
                /* allocate memory for the BDL for each stream */
                err = bus->io_ops->dma_alloc_pages(bus, SNDRV_DMA_TYPE_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 = bus->io_ops->dma_alloc_pages(bus, SNDRV_DMA_TYPE_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 bus->io_ops->dma_alloc_pages(bus, SNDRV_DMA_TYPE_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)
                        bus->io_ops->dma_free_pages(bus, &s->bdl);
        }

        if (bus->rb.area)
                bus->io_ops->dma_free_pages(bus, &bus->rb);
        if (bus->posbuf.area)
                bus->io_ops->dma_free_pages(bus, &bus->posbuf);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_free_stream_pages);