diff options
Diffstat (limited to 'drivers/acpi')
| -rw-r--r-- | drivers/acpi/arm64/iort.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c index 770d84071a32..d4eac6d7e9fb 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c @@ -1720,3 +1720,58 @@ void __init acpi_iort_init(void) iort_init_platform_devices(); } + +#ifdef CONFIG_ZONE_DMA +/* + * Extract the highest CPU physical address accessible to all DMA masters in + * the system. PHYS_ADDR_MAX is returned when no constrained device is found. + */ +phys_addr_t __init acpi_iort_dma_get_max_cpu_address(void) +{ + phys_addr_t limit = PHYS_ADDR_MAX; + struct acpi_iort_node *node, *end; + struct acpi_table_iort *iort; + acpi_status status; + int i; + + if (acpi_disabled) + return limit; + + status = acpi_get_table(ACPI_SIG_IORT, 0, + (struct acpi_table_header **)&iort); + if (ACPI_FAILURE(status)) + return limit; + + node = ACPI_ADD_PTR(struct acpi_iort_node, iort, iort->node_offset); + end = ACPI_ADD_PTR(struct acpi_iort_node, iort, iort->header.length); + + for (i = 0; i < iort->node_count; i++) { + if (node >= end) + break; + + switch (node->type) { + struct acpi_iort_named_component *ncomp; + struct acpi_iort_root_complex *rc; + phys_addr_t local_limit; + + case ACPI_IORT_NODE_NAMED_COMPONENT: + ncomp = (struct acpi_iort_named_component *)node->node_data; + local_limit = DMA_BIT_MASK(ncomp->memory_address_limit); + limit = min_not_zero(limit, local_limit); + break; + + case ACPI_IORT_NODE_PCI_ROOT_COMPLEX: + if (node->revision < 1) + break; + + rc = (struct acpi_iort_root_complex *)node->node_data; + local_limit = DMA_BIT_MASK(rc->memory_address_limit); + limit = min_not_zero(limit, local_limit); + break; + } + node = ACPI_ADD_PTR(struct acpi_iort_node, node, node->length); + } + acpi_put_table(&iort->header); + return limit; +} +#endif |