int qmgr_request_queue()

in ixp4xx/ixp4xx-qmgr.c [239:327]

• 79 lines of code
• 14 McCabe index (conditional complexity)

int qmgr_request_queue(unsigned int queue, unsigned int len /* dwords */,
		       unsigned int nearly_empty_watermark,
		       unsigned int nearly_full_watermark,
		       const char *desc_format, const char* name)
#else
int __qmgr_request_queue(unsigned int queue, unsigned int len /* dwords */,
			 unsigned int nearly_empty_watermark,
			 unsigned int nearly_full_watermark)
#endif
{
	u32 cfg, addr = 0, mask[4]; /* in 16-dwords */
	int err;

	BUG_ON(queue >= QUEUES);

	if ((nearly_empty_watermark | nearly_full_watermark) & ~7)
		return -EINVAL;

	switch (len) {
	case  16:
		cfg = 0 << 24;
		mask[0] = 0x1;
		break;
	case  32:
		cfg = 1 << 24;
		mask[0] = 0x3;
		break;
	case  64:
		cfg = 2 << 24;
		mask[0] = 0xF;
		break;
	case 128:
		cfg = 3 << 24;
		mask[0] = 0xFF;
		break;
	default:
		return -EINVAL;
	}

	cfg |= nearly_empty_watermark << 26;
	cfg |= nearly_full_watermark << 29;
	len /= 16;		/* in 16-dwords: 1, 2, 4 or 8 */
	mask[1] = mask[2] = mask[3] = 0;

	if (!try_module_get(THIS_MODULE))
		return -ENODEV;

	spin_lock_irq(&qmgr_lock);
	if (__raw_readl(&qmgr_regs->sram[queue])) {
		err = -EBUSY;
		goto err;
	}

	while (1) {
		if (!(used_sram_bitmap[0] & mask[0]) &&
		    !(used_sram_bitmap[1] & mask[1]) &&
		    !(used_sram_bitmap[2] & mask[2]) &&
		    !(used_sram_bitmap[3] & mask[3]))
			break; /* found free space */

		addr++;
		shift_mask(mask);
		if (addr + len > ARRAY_SIZE(qmgr_regs->sram)) {
			printk(KERN_ERR "qmgr: no free SRAM space for"
			       " queue %i\n", queue);
			err = -ENOMEM;
			goto err;
		}
	}

	used_sram_bitmap[0] |= mask[0];
	used_sram_bitmap[1] |= mask[1];
	used_sram_bitmap[2] |= mask[2];
	used_sram_bitmap[3] |= mask[3];
	__raw_writel(cfg | (addr << 14), &qmgr_regs->sram[queue]);
#if DEBUG_QMGR
	snprintf(qmgr_queue_descs[queue], sizeof(qmgr_queue_descs[0]),
		 desc_format, name);
	printk(KERN_DEBUG "qmgr: requested queue %s(%i) addr = 0x%02X\n",
	       qmgr_queue_descs[queue], queue, addr);
#endif
	spin_unlock_irq(&qmgr_lock);
	return 0;

err:
	spin_unlock_irq(&qmgr_lock);
	module_put(THIS_MODULE);
	return err;
}