static int clk_establish_mapping()

in clk/core.c [338:386]

• 27 lines of code
• 7 McCabe index (conditional complexity)

static int clk_establish_mapping(struct clk *clk)
{
	struct clk_mapping *mapping = clk->mapping;

	/*
	 * Propagate mappings.
	 */
	if (!mapping) {
		struct clk *clkp;

		/*
		 * dummy mapping for root clocks with no specified ranges
		 */
		if (!clk->parent) {
			clk->mapping = &dummy_mapping;
			goto out;
		}

		/*
		 * If we're on a child clock and it provides no mapping of its
		 * own, inherit the mapping from its root clock.
		 */
		clkp = lookup_root_clock(clk);
		mapping = clkp->mapping;
		BUG_ON(!mapping);
	}

	/*
	 * Establish initial mapping.
	 */
	if (!mapping->base && mapping->phys) {
		kref_init(&mapping->ref);

		mapping->base = ioremap(mapping->phys, mapping->len);
		if (unlikely(!mapping->base))
			return -ENXIO;
	} else if (mapping->base) {
		/*
		 * Bump the refcount for an existing mapping
		 */
		kref_get(&mapping->ref);
	}

	clk->mapping = mapping;
out:
	clk->mapped_reg = clk->mapping->base;
	clk->mapped_reg += (phys_addr_t)clk->enable_reg - clk->mapping->phys;
	return 0;
}