lib/logic_pio.c

Source file repositories/reference/linux-study-clean/lib/logic_pio.c

File Facts

System
Linux kernel
Corpus path
lib/logic_pio.c
Extension
.c
Size
8587 bytes
Lines
318
Domain
Kernel Services
Bucket
lib
Inferred role
Kernel Services: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Shared kernel service surface used by multiple subsystems, including helpers, cryptography, virtualization support, and async I/O infrastructure.

Dependency Surface

Detected Declarations

Annotated Snippet

if (range->fwnode == new_range->fwnode) {
			/* range already there */
			ret = -EEXIST;
			goto end_register;
		}
		if (range->flags == LOGIC_PIO_CPU_MMIO &&
		    new_range->flags == LOGIC_PIO_CPU_MMIO) {
			/* for MMIO ranges we need to check for overlap */
			if (start >= range->hw_start + range->size ||
			    end < range->hw_start) {
				mmio_end = range->io_start + range->size;
			} else {
				ret = -EFAULT;
				goto end_register;
			}
		} else if (range->flags == LOGIC_PIO_INDIRECT &&
			   new_range->flags == LOGIC_PIO_INDIRECT) {
			iio_sz += range->size;
		}
	}

	/* range not registered yet, check for available space */
	if (new_range->flags == LOGIC_PIO_CPU_MMIO) {
		if (mmio_end + new_range->size - 1 > MMIO_UPPER_LIMIT) {
			/* if it's too big check if 64K space can be reserved */
			if (mmio_end + SZ_64K - 1 > MMIO_UPPER_LIMIT) {
				ret = -E2BIG;
				goto end_register;
			}
			new_range->size = SZ_64K;
			pr_warn("Requested IO range too big, new size set to 64K\n");
		}
		new_range->io_start = mmio_end;
	} else if (new_range->flags == LOGIC_PIO_INDIRECT) {
		if (iio_sz + new_range->size - 1 > IO_SPACE_LIMIT) {
			ret = -E2BIG;
			goto end_register;
		}
		new_range->io_start = iio_sz;
	} else {
		/* invalid flag */
		ret = -EINVAL;
		goto end_register;
	}

	list_add_tail_rcu(&new_range->list, &io_range_list);

end_register:
	mutex_unlock(&io_range_mutex);
	return ret;
}

/**
 * logic_pio_unregister_range - unregister a logical PIO range for a host
 * @range: pointer to the IO range which has been already registered.
 *
 * Unregister a previously-registered IO range node.
 */
void logic_pio_unregister_range(struct logic_pio_hwaddr *range)
{
	mutex_lock(&io_range_mutex);
	list_del_rcu(&range->list);
	mutex_unlock(&io_range_mutex);
	synchronize_rcu();
}

/**
 * find_io_range_by_fwnode - find logical PIO range for given FW node
 * @fwnode: FW node handle associated with logical PIO range
 *
 * Returns pointer to node on success, NULL otherwise.
 *
 * Traverse the io_range_list to find the registered node for @fwnode.
 */
struct logic_pio_hwaddr *find_io_range_by_fwnode(const struct fwnode_handle *fwnode)
{
	struct logic_pio_hwaddr *range, *found_range = NULL;

	rcu_read_lock();
	list_for_each_entry_rcu(range, &io_range_list, list) {
		if (range->fwnode == fwnode) {
			found_range = range;
			break;
		}
	}
	rcu_read_unlock();

	return found_range;
}

Annotation

Implementation Notes