root/sound/isa/gus/gus_dma.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Routines for GF1 DMA control
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 */

#include <asm/dma.h>
#include <linux/slab.h>
#include <sound/core.h>
#include <sound/gus.h>

static void snd_gf1_dma_ack(struct snd_gus_card * gus)
{
        guard(spinlock_irqsave)(&gus->reg_lock);
        snd_gf1_write8(gus, SNDRV_GF1_GB_DRAM_DMA_CONTROL, 0x00);
        snd_gf1_look8(gus, SNDRV_GF1_GB_DRAM_DMA_CONTROL);
}

static void snd_gf1_dma_program(struct snd_gus_card * gus,
                                unsigned int addr,
                                unsigned long buf_addr,
                                unsigned int count,
                                unsigned int cmd)
{
        unsigned int address;
        unsigned char dma_cmd;
        unsigned int address_high;

        dev_dbg(gus->card->dev,
                "dma_transfer: addr=0x%x, buf=0x%lx, count=0x%x\n",
                addr, buf_addr, count);

        if (gus->gf1.dma1 > 3) {
                if (gus->gf1.enh_mode) {
                        address = addr >> 1;
                } else {
                        if (addr & 0x1f) {
                                dev_dbg(gus->card->dev,
                                        "%s: unaligned address (0x%x)?\n",
                                        __func__, addr);
                                return;
                        }
                        address = (addr & 0x000c0000) | ((addr & 0x0003ffff) >> 1);
                }
        } else {
                address = addr;
        }

        dma_cmd = SNDRV_GF1_DMA_ENABLE | (unsigned short) cmd;
#if 0
        dma_cmd |= 0x08;
#endif
        if (dma_cmd & SNDRV_GF1_DMA_16BIT) {
                count++;
                count &= ~1;    /* align */
        }
        if (gus->gf1.dma1 > 3) {
                dma_cmd |= SNDRV_GF1_DMA_WIDTH16;
                count++;
                count &= ~1;    /* align */
        }
        snd_gf1_dma_ack(gus);
        snd_dma_program(gus->gf1.dma1, buf_addr, count, dma_cmd & SNDRV_GF1_DMA_READ ? DMA_MODE_READ : DMA_MODE_WRITE);
#if 0
        dev_dbg(gus->card->dev,
                "address = 0x%x, count = 0x%x, dma_cmd = 0x%x\n",
                address << 1, count, dma_cmd);
#endif
        guard(spinlock_irqsave)(&gus->reg_lock);
        if (gus->gf1.enh_mode) {
                address_high = ((address >> 16) & 0x000000f0) | (address & 0x0000000f);
                snd_gf1_write16(gus, SNDRV_GF1_GW_DRAM_DMA_LOW, (unsigned short) (address >> 4));
                snd_gf1_write8(gus, SNDRV_GF1_GB_DRAM_DMA_HIGH, (unsigned char) address_high);
        } else
                snd_gf1_write16(gus, SNDRV_GF1_GW_DRAM_DMA_LOW, (unsigned short) (address >> 4));
        snd_gf1_write8(gus, SNDRV_GF1_GB_DRAM_DMA_CONTROL, dma_cmd);
}

static struct snd_gf1_dma_block *snd_gf1_dma_next_block(struct snd_gus_card * gus)
{
        struct snd_gf1_dma_block *block;

        /* PCM block have bigger priority than synthesizer one */
        if (gus->gf1.dma_data_pcm) {
                block = gus->gf1.dma_data_pcm;
                if (gus->gf1.dma_data_pcm_last == block) {
                        gus->gf1.dma_data_pcm =
                        gus->gf1.dma_data_pcm_last = NULL;
                } else {
                        gus->gf1.dma_data_pcm = block->next;
                }
        } else if (gus->gf1.dma_data_synth) {
                block = gus->gf1.dma_data_synth;
                if (gus->gf1.dma_data_synth_last == block) {
                        gus->gf1.dma_data_synth =
                        gus->gf1.dma_data_synth_last = NULL;
                } else {
                        gus->gf1.dma_data_synth = block->next;
                }
        } else {
                block = NULL;
        }
        if (block) {
                gus->gf1.dma_ack = block->ack;
                gus->gf1.dma_private_data = block->private_data;
        }
        return block;
}


static void snd_gf1_dma_interrupt(struct snd_gus_card * gus)
{
        struct snd_gf1_dma_block *block;

        snd_gf1_dma_ack(gus);
        if (gus->gf1.dma_ack)
                gus->gf1.dma_ack(gus, gus->gf1.dma_private_data);
        scoped_guard(spinlock, &gus->dma_lock) {
                if (gus->gf1.dma_data_pcm == NULL &&
                    gus->gf1.dma_data_synth == NULL) {
                        gus->gf1.dma_ack = NULL;
                        gus->gf1.dma_flags &= ~SNDRV_GF1_DMA_TRIGGER;
                        return;
                }
                block = snd_gf1_dma_next_block(gus);
        }
        if (!block)
                return;
        snd_gf1_dma_program(gus, block->addr, block->buf_addr, block->count, (unsigned short) block->cmd);
        kfree(block);
#if 0
        dev_dbg(gus->card->dev,
                "program dma (IRQ) - addr = 0x%x, buffer = 0x%lx, count = 0x%x, cmd = 0x%x\n",
                block->addr, block->buf_addr, block->count, block->cmd);
#endif
}

int snd_gf1_dma_init(struct snd_gus_card * gus)
{
        guard(mutex)(&gus->dma_mutex);
        gus->gf1.dma_shared++;
        if (gus->gf1.dma_shared > 1)
                return 0;
        gus->gf1.interrupt_handler_dma_write = snd_gf1_dma_interrupt;
        gus->gf1.dma_data_pcm = 
        gus->gf1.dma_data_pcm_last =
        gus->gf1.dma_data_synth = 
        gus->gf1.dma_data_synth_last = NULL;
        return 0;
}

int snd_gf1_dma_done(struct snd_gus_card * gus)
{
        struct snd_gf1_dma_block *block;

        guard(mutex)(&gus->dma_mutex);
        gus->gf1.dma_shared--;
        if (!gus->gf1.dma_shared) {
                snd_dma_disable(gus->gf1.dma1);
                snd_gf1_set_default_handlers(gus, SNDRV_GF1_HANDLER_DMA_WRITE);
                snd_gf1_dma_ack(gus);
                while ((block = gus->gf1.dma_data_pcm)) {
                        gus->gf1.dma_data_pcm = block->next;
                        kfree(block);
                }
                while ((block = gus->gf1.dma_data_synth)) {
                        gus->gf1.dma_data_synth = block->next;
                        kfree(block);
                }
                gus->gf1.dma_data_pcm_last =
                gus->gf1.dma_data_synth_last = NULL;
        }
        return 0;
}

int snd_gf1_dma_transfer_block(struct snd_gus_card * gus,
                               struct snd_gf1_dma_block * __block,
                               int atomic,
                               int synth)
{
        struct snd_gf1_dma_block *block;
        struct snd_gf1_dma_block *free_block = NULL;

        block = kmalloc(sizeof(*block), atomic ? GFP_ATOMIC : GFP_KERNEL);
        if (!block)
                return -ENOMEM;

        *block = *__block;
        block->next = NULL;

        dev_dbg(gus->card->dev,
                "addr = 0x%x, buffer = 0x%lx, count = 0x%x, cmd = 0x%x\n",
                block->addr, (long) block->buffer, block->count,
                block->cmd);

        dev_dbg(gus->card->dev,
                "gus->gf1.dma_data_pcm_last = 0x%lx\n",
                (long)gus->gf1.dma_data_pcm_last);
        dev_dbg(gus->card->dev,
                "gus->gf1.dma_data_pcm = 0x%lx\n",
                (long)gus->gf1.dma_data_pcm);

        scoped_guard(spinlock_irqsave, &gus->dma_lock) {
                if (synth) {
                        if (gus->gf1.dma_data_synth_last) {
                                gus->gf1.dma_data_synth_last->next = block;
                                gus->gf1.dma_data_synth_last = block;
                        } else {
                                gus->gf1.dma_data_synth =
                                        gus->gf1.dma_data_synth_last = block;
                        }
                } else {
                        if (gus->gf1.dma_data_pcm_last) {
                                gus->gf1.dma_data_pcm_last->next = block;
                                gus->gf1.dma_data_pcm_last = block;
                        } else {
                                gus->gf1.dma_data_pcm =
                                        gus->gf1.dma_data_pcm_last = block;
                        }
                }
                if (!(gus->gf1.dma_flags & SNDRV_GF1_DMA_TRIGGER)) {
                        gus->gf1.dma_flags |= SNDRV_GF1_DMA_TRIGGER;
                        free_block = snd_gf1_dma_next_block(gus);
                }
        }

        if (free_block) {
                snd_gf1_dma_program(gus, free_block->addr, free_block->buf_addr,
                                    free_block->count,
                                    (unsigned short)free_block->cmd);
                kfree(free_block);
        }

        return 0;
}