sound/isa/gus/gus_dma.c

Source file repositories/reference/linux-study-clean/sound/isa/gus/gus_dma.c

File Facts

System
Linux kernel
Corpus path
sound/isa/gus/gus_dma.c
Extension
.c
Size
6991 bytes
Lines
269
Domain
Driver Families
Bucket
sound/isa
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

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;

Annotation

Implementation Notes