// 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;
}