drivers/scsi/a3000.c

Source file repositories/reference/linux-study-clean/drivers/scsi/a3000.c

File Facts

System
Linux kernel
Corpus path
drivers/scsi/a3000.c
Extension
.c
Size
8438 bytes
Lines
316
Domain
Driver Families
Bucket
drivers/scsi
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

struct a3000_hostdata {
	struct WD33C93_hostdata wh;
	struct a3000_scsiregs *regs;
	struct device *dev;
};

#define DMA_DIR(d)   ((d == DATA_OUT_DIR) ? DMA_TO_DEVICE : DMA_FROM_DEVICE)

static irqreturn_t a3000_intr(int irq, void *data)
{
	struct Scsi_Host *instance = data;
	struct a3000_hostdata *hdata = shost_priv(instance);
	unsigned int status = hdata->regs->ISTR;
	unsigned long flags;

	if (!(status & ISTR_INT_P))
		return IRQ_NONE;
	if (status & ISTR_INTS) {
		spin_lock_irqsave(instance->host_lock, flags);
		wd33c93_intr(instance);
		spin_unlock_irqrestore(instance->host_lock, flags);
		return IRQ_HANDLED;
	}
	pr_warn("Non-serviced A3000 SCSI-interrupt? ISTR = %02x\n", status);
	return IRQ_NONE;
}

static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
{
	struct scsi_pointer *scsi_pointer = WD33C93_scsi_pointer(cmd);
	unsigned long len = scsi_pointer->this_residual;
	struct Scsi_Host *instance = cmd->device->host;
	struct a3000_hostdata *hdata = shost_priv(instance);
	struct WD33C93_hostdata *wh = &hdata->wh;
	struct a3000_scsiregs *regs = hdata->regs;
	unsigned short cntr = CNTR_PDMD | CNTR_INTEN;
	dma_addr_t addr;

	addr = dma_map_single(hdata->dev, scsi_pointer->ptr,
			      len, DMA_DIR(dir_in));
	if (dma_mapping_error(hdata->dev, addr)) {
		dev_warn(hdata->dev, "cannot map SCSI data block %p\n",
			 scsi_pointer->ptr);
		return 1;
	}
	scsi_pointer->dma_handle = addr;

	/*
	 * if the physical address has the wrong alignment, or if
	 * physical address is bad, or if it is a write and at the
	 * end of a physical memory chunk, then allocate a bounce
	 * buffer
	 * MSch 20220629 - only wrong alignment tested - bounce
	 * buffer returned by kmalloc is guaranteed to be aligned
	 */
	if (addr & A3000_XFER_MASK) {
		WARN_ONCE(1, "Invalid alignment for DMA!");
		/* drop useless mapping */
		dma_unmap_single(hdata->dev, scsi_pointer->dma_handle,
				 scsi_pointer->this_residual,
				 DMA_DIR(dir_in));

		wh->dma_bounce_len = (scsi_pointer->this_residual + 511) & ~0x1ff;
		wh->dma_bounce_buffer = kmalloc(wh->dma_bounce_len,
						GFP_KERNEL);

		/* can't allocate memory; use PIO */
		if (!wh->dma_bounce_buffer) {
			wh->dma_bounce_len = 0;
			scsi_pointer->dma_handle = (dma_addr_t) NULL;
			return 1;
		}

		if (!dir_in) {
			/* copy to bounce buffer for a write */
			memcpy(wh->dma_bounce_buffer, scsi_pointer->ptr,
			       scsi_pointer->this_residual);
		}

		addr = dma_map_single(hdata->dev, scsi_pointer->ptr,
				      len, DMA_DIR(dir_in));
		if (dma_mapping_error(hdata->dev, addr)) {
			dev_warn(hdata->dev,
				 "cannot map SCSI data block %p\n",
				 scsi_pointer->ptr);
			return 1;
		}
		scsi_pointer->dma_handle = addr;
	}

Annotation

Implementation Notes