static int its_setup_baser()

in irq-gic-v3-its.c [2292:2397]

• 81 lines of code
• 15 McCabe index (conditional complexity)

static int its_setup_baser(struct its_node *its, struct its_baser *baser,
			   u64 cache, u64 shr, u32 order, bool indirect)
{
	u64 val = its_read_baser(its, baser);
	u64 esz = GITS_BASER_ENTRY_SIZE(val);
	u64 type = GITS_BASER_TYPE(val);
	u64 baser_phys, tmp;
	u32 alloc_pages, psz;
	struct page *page;
	void *base;

	psz = baser->psz;
	alloc_pages = (PAGE_ORDER_TO_SIZE(order) / psz);
	if (alloc_pages > GITS_BASER_PAGES_MAX) {
		pr_warn("ITS@%pa: %s too large, reduce ITS pages %u->%u\n",
			&its->phys_base, its_base_type_string[type],
			alloc_pages, GITS_BASER_PAGES_MAX);
		alloc_pages = GITS_BASER_PAGES_MAX;
		order = get_order(GITS_BASER_PAGES_MAX * psz);
	}

	page = alloc_pages_node(its->numa_node, GFP_KERNEL | __GFP_ZERO, order);
	if (!page)
		return -ENOMEM;

	base = (void *)page_address(page);
	baser_phys = virt_to_phys(base);

	/* Check if the physical address of the memory is above 48bits */
	if (IS_ENABLED(CONFIG_ARM64_64K_PAGES) && (baser_phys >> 48)) {

		/* 52bit PA is supported only when PageSize=64K */
		if (psz != SZ_64K) {
			pr_err("ITS: no 52bit PA support when psz=%d\n", psz);
			free_pages((unsigned long)base, order);
			return -ENXIO;
		}

		/* Convert 52bit PA to 48bit field */
		baser_phys = GITS_BASER_PHYS_52_to_48(baser_phys);
	}

retry_baser:
	val = (baser_phys					 |
		(type << GITS_BASER_TYPE_SHIFT)			 |
		((esz - 1) << GITS_BASER_ENTRY_SIZE_SHIFT)	 |
		((alloc_pages - 1) << GITS_BASER_PAGES_SHIFT)	 |
		cache						 |
		shr						 |
		GITS_BASER_VALID);

	val |=	indirect ? GITS_BASER_INDIRECT : 0x0;

	switch (psz) {
	case SZ_4K:
		val |= GITS_BASER_PAGE_SIZE_4K;
		break;
	case SZ_16K:
		val |= GITS_BASER_PAGE_SIZE_16K;
		break;
	case SZ_64K:
		val |= GITS_BASER_PAGE_SIZE_64K;
		break;
	}

	its_write_baser(its, baser, val);
	tmp = baser->val;

	if ((val ^ tmp) & GITS_BASER_SHAREABILITY_MASK) {
		/*
		 * Shareability didn't stick. Just use
		 * whatever the read reported, which is likely
		 * to be the only thing this redistributor
		 * supports. If that's zero, make it
		 * non-cacheable as well.
		 */
		shr = tmp & GITS_BASER_SHAREABILITY_MASK;
		if (!shr) {
			cache = GITS_BASER_nC;
			gic_flush_dcache_to_poc(base, PAGE_ORDER_TO_SIZE(order));
		}
		goto retry_baser;
	}

	if (val != tmp) {
		pr_err("ITS@%pa: %s doesn't stick: %llx %llx\n",
		       &its->phys_base, its_base_type_string[type],
		       val, tmp);
		free_pages((unsigned long)base, order);
		return -ENXIO;
	}

	baser->order = order;
	baser->base = base;
	baser->psz = psz;
	tmp = indirect ? GITS_LVL1_ENTRY_SIZE : esz;

	pr_info("ITS@%pa: allocated %d %s @%lx (%s, esz %d, psz %dK, shr %d)\n",
		&its->phys_base, (int)(PAGE_ORDER_TO_SIZE(order) / (int)tmp),
		its_base_type_string[type],
		(unsigned long)virt_to_phys(base),
		indirect ? "indirect" : "flat", (int)esz,
		psz / SZ_1K, (int)shr >> GITS_BASER_SHAREABILITY_SHIFT);

	return 0;
}