root/sound/soc/samsung/idma.c
// SPDX-License-Identifier: GPL-2.0+
//
// idma.c - I2S0 internal DMA driver
//
// Copyright (c) 2011 Samsung Electronics Co., Ltd.
//              http://www.samsung.com

#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include "i2s.h"
#include "idma.h"
#include "i2s-regs.h"

#define ST_RUNNING              (1<<0)
#define ST_OPENED               (1<<1)

static const struct snd_pcm_hardware idma_hardware = {
        .info = SNDRV_PCM_INFO_INTERLEAVED |
                    SNDRV_PCM_INFO_BLOCK_TRANSFER |
                    SNDRV_PCM_INFO_MMAP |
                    SNDRV_PCM_INFO_MMAP_VALID |
                    SNDRV_PCM_INFO_PAUSE |
                    SNDRV_PCM_INFO_RESUME,
        .buffer_bytes_max = MAX_IDMA_BUFFER,
        .period_bytes_min = 128,
        .period_bytes_max = MAX_IDMA_PERIOD,
        .periods_min = 1,
        .periods_max = 2,
};

struct idma_ctrl {
        spinlock_t      lock;
        int             state;
        dma_addr_t      start;
        dma_addr_t      pos;
        dma_addr_t      end;
        dma_addr_t      period;
        dma_addr_t      periodsz;
        void            *token;
        void            (*cb)(void *dt, int bytes_xfer);
};

static struct idma_info {
        spinlock_t      lock;
        void             __iomem  *regs;
        dma_addr_t      lp_tx_addr;
} idma;

static int idma_irq;

static void idma_getpos(dma_addr_t *src)
{
        *src = idma.lp_tx_addr +
                (readl(idma.regs + I2STRNCNT) & 0xffffff) * 4;
}

static int idma_enqueue(struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct idma_ctrl *prtd = substream->runtime->private_data;
        u32 val;

        spin_lock(&prtd->lock);
        prtd->token = (void *) substream;
        spin_unlock(&prtd->lock);

        /* Internal DMA Level0 Interrupt Address */
        val = idma.lp_tx_addr + prtd->periodsz;
        writel(val, idma.regs + I2SLVL0ADDR);

        /* Start address0 of I2S internal DMA operation. */
        val = idma.lp_tx_addr;
        writel(val, idma.regs + I2SSTR0);

        /*
         * Transfer block size for I2S internal DMA.
         * Should decide transfer size before start dma operation
         */
        val = readl(idma.regs + I2SSIZE);
        val &= ~(I2SSIZE_TRNMSK << I2SSIZE_SHIFT);
        val |= (((runtime->dma_bytes >> 2) &
                        I2SSIZE_TRNMSK) << I2SSIZE_SHIFT);
        writel(val, idma.regs + I2SSIZE);

        val = readl(idma.regs + I2SAHB);
        val |= AHB_INTENLVL0;
        writel(val, idma.regs + I2SAHB);

        return 0;
}

static void idma_setcallbk(struct snd_pcm_substream *substream,
                                void (*cb)(void *, int))
{
        struct idma_ctrl *prtd = substream->runtime->private_data;

        spin_lock(&prtd->lock);
        prtd->cb = cb;
        spin_unlock(&prtd->lock);
}

static void idma_control(int op)
{
        u32 val = readl(idma.regs + I2SAHB);

        spin_lock(&idma.lock);

        switch (op) {
        case LPAM_DMA_START:
                val |= (AHB_INTENLVL0 | AHB_DMAEN);
                break;
        case LPAM_DMA_STOP:
                val &= ~(AHB_INTENLVL0 | AHB_DMAEN);
                break;
        default:
                spin_unlock(&idma.lock);
                return;
        }

        writel(val, idma.regs + I2SAHB);
        spin_unlock(&idma.lock);
}

static void idma_done(void *id, int bytes_xfer)
{
        struct snd_pcm_substream *substream = id;
        struct idma_ctrl *prtd = substream->runtime->private_data;

        if (prtd && (prtd->state & ST_RUNNING))
                snd_pcm_period_elapsed(substream);
}

static int idma_hw_params(struct snd_soc_component *component,
                          struct snd_pcm_substream *substream,
                          struct snd_pcm_hw_params *params)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct idma_ctrl *prtd = substream->runtime->private_data;
        u32 mod = readl(idma.regs + I2SMOD);
        u32 ahb = readl(idma.regs + I2SAHB);

        ahb |= (AHB_DMARLD | AHB_INTMASK);
        mod |= MOD_TXS_IDMA;
        writel(ahb, idma.regs + I2SAHB);
        writel(mod, idma.regs + I2SMOD);

        snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
        runtime->dma_bytes = params_buffer_bytes(params);

        prtd->start = prtd->pos = runtime->dma_addr;
        prtd->period = params_periods(params);
        prtd->periodsz = params_period_bytes(params);
        prtd->end = runtime->dma_addr + runtime->dma_bytes;

        idma_setcallbk(substream, idma_done);

        return 0;
}

static int idma_hw_free(struct snd_soc_component *component,
                        struct snd_pcm_substream *substream)
{
        snd_pcm_set_runtime_buffer(substream, NULL);

        return 0;
}

static int idma_prepare(struct snd_soc_component *component,
                        struct snd_pcm_substream *substream)
{
        struct idma_ctrl *prtd = substream->runtime->private_data;

        prtd->pos = prtd->start;

        /* flush the DMA channel */
        idma_control(LPAM_DMA_STOP);
        idma_enqueue(substream);

        return 0;
}

static int idma_trigger(struct snd_soc_component *component,
                        struct snd_pcm_substream *substream, int cmd)
{
        struct idma_ctrl *prtd = substream->runtime->private_data;
        int ret = 0;

        spin_lock(&prtd->lock);

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_RESUME:
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                prtd->state |= ST_RUNNING;
                idma_control(LPAM_DMA_START);
                break;

        case SNDRV_PCM_TRIGGER_SUSPEND:
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                prtd->state &= ~ST_RUNNING;
                idma_control(LPAM_DMA_STOP);
                break;

        default:
                ret = -EINVAL;
                break;
        }

        spin_unlock(&prtd->lock);

        return ret;
}

static snd_pcm_uframes_t
idma_pointer(struct snd_soc_component *component,
             struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct idma_ctrl *prtd = runtime->private_data;
        dma_addr_t src;
        unsigned long res;

        spin_lock(&prtd->lock);

        idma_getpos(&src);
        res = src - prtd->start;

        spin_unlock(&prtd->lock);

        return bytes_to_frames(substream->runtime, res);
}

static int idma_mmap(struct snd_soc_component *component,
                     struct snd_pcm_substream *substream,
        struct vm_area_struct *vma)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        unsigned long size, offset;

        /* From snd_pcm_lib_mmap_iomem */
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
        size = vma->vm_end - vma->vm_start;
        offset = vma->vm_pgoff << PAGE_SHIFT;
        return io_remap_pfn_range(vma, vma->vm_start,
                        (runtime->dma_addr + offset) >> PAGE_SHIFT,
                        size, vma->vm_page_prot);
}

static irqreturn_t iis_irq(int irqno, void *dev_id)
{
        struct idma_ctrl *prtd = (struct idma_ctrl *)dev_id;
        u32 iisahb, val, addr;

        iisahb  = readl(idma.regs + I2SAHB);

        val = (iisahb & AHB_LVL0INT) ? AHB_CLRLVL0INT : 0;

        if (val) {
                iisahb |= val;
                writel(iisahb, idma.regs + I2SAHB);

                addr = readl(idma.regs + I2SLVL0ADDR) - idma.lp_tx_addr;
                addr += prtd->periodsz;
                addr %= (u32)(prtd->end - prtd->start);
                addr += idma.lp_tx_addr;

                writel(addr, idma.regs + I2SLVL0ADDR);

                if (prtd->cb)
                        prtd->cb(prtd->token, prtd->period);
        }

        return IRQ_HANDLED;
}

static int idma_open(struct snd_soc_component *component,
                     struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct idma_ctrl *prtd;
        int ret;

        snd_soc_set_runtime_hwparams(substream, &idma_hardware);

        prtd = kzalloc_obj(struct idma_ctrl);
        if (prtd == NULL)
                return -ENOMEM;

        ret = request_irq(idma_irq, iis_irq, 0, "i2s", prtd);
        if (ret < 0) {
                pr_err("fail to claim i2s irq , ret = %d\n", ret);
                kfree(prtd);
                return ret;
        }

        spin_lock_init(&prtd->lock);

        runtime->private_data = prtd;

        return 0;
}

static int idma_close(struct snd_soc_component *component,
                      struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct idma_ctrl *prtd = runtime->private_data;

        free_irq(idma_irq, prtd);

        if (!prtd)
                pr_err("idma_close called with prtd == NULL\n");

        kfree(prtd);

        return 0;
}

static void idma_free(struct snd_soc_component *component,
                      struct snd_pcm *pcm)
{
        struct snd_pcm_substream *substream;
        struct snd_dma_buffer *buf;

        substream = pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
        if (!substream)
                return;

        buf = &substream->dma_buffer;
        if (!buf->area)
                return;

        iounmap((void __iomem *)buf->area);

        buf->area = NULL;
        buf->addr = 0;
}

static int preallocate_idma_buffer(struct snd_pcm *pcm, int stream)
{
        struct snd_pcm_substream *substream = pcm->streams[stream].substream;
        struct snd_dma_buffer *buf = &substream->dma_buffer;

        buf->dev.dev = pcm->card->dev;
        buf->private_data = NULL;

        /* Assign PCM buffer pointers */
        buf->dev.type = SNDRV_DMA_TYPE_CONTINUOUS;
        buf->addr = idma.lp_tx_addr;
        buf->bytes = idma_hardware.buffer_bytes_max;
        buf->area = (unsigned char * __force)ioremap(buf->addr, buf->bytes);
        if (!buf->area)
                return -ENOMEM;

        return 0;
}

static int idma_new(struct snd_soc_component *component,
                    struct snd_soc_pcm_runtime *rtd)
{
        struct snd_card *card = rtd->card->snd_card;
        struct snd_pcm *pcm = rtd->pcm;
        int ret;

        ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
        if (ret)
                return ret;

        if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
                ret = preallocate_idma_buffer(pcm,
                                SNDRV_PCM_STREAM_PLAYBACK);
        }

        return ret;
}

void idma_reg_addr_init(void __iomem *regs, dma_addr_t addr)
{
        spin_lock_init(&idma.lock);
        idma.regs = regs;
        idma.lp_tx_addr = addr;
}
EXPORT_SYMBOL_GPL(idma_reg_addr_init);

static const struct snd_soc_component_driver asoc_idma_platform = {
        .open           = idma_open,
        .close          = idma_close,
        .trigger        = idma_trigger,
        .pointer        = idma_pointer,
        .mmap           = idma_mmap,
        .hw_params      = idma_hw_params,
        .hw_free        = idma_hw_free,
        .prepare        = idma_prepare,
        .pcm_construct  = idma_new,
        .pcm_destruct   = idma_free,
};

static int asoc_idma_platform_probe(struct platform_device *pdev)
{
        idma_irq = platform_get_irq(pdev, 0);
        if (idma_irq < 0)
                return idma_irq;

        return devm_snd_soc_register_component(&pdev->dev, &asoc_idma_platform,
                                               NULL, 0);
}

static struct platform_driver asoc_idma_driver = {
        .driver = {
                .name = "samsung-idma",
        },

        .probe = asoc_idma_platform_probe,
};

module_platform_driver(asoc_idma_driver);

MODULE_AUTHOR("Jaswinder Singh, <jassisinghbrar@gmail.com>");
MODULE_DESCRIPTION("Samsung ASoC IDMA Driver");
MODULE_LICENSE("GPL");