diff options
Diffstat (limited to 'doc/opal-api/opal-pci-phb-mmio-enable-27.txt')
| -rw-r--r-- | doc/opal-api/opal-pci-phb-mmio-enable-27.txt | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/doc/opal-api/opal-pci-phb-mmio-enable-27.txt b/doc/opal-api/opal-pci-phb-mmio-enable-27.txt new file mode 100644 index 0000000..c5b08f4 --- /dev/null +++ b/doc/opal-api/opal-pci-phb-mmio-enable-27.txt @@ -0,0 +1,44 @@ +OPAL_PCI_PHB_MMIO_ENABLE +------------------------ + +#define OPAL_PCI_PHB_MMIO_ENABLE 27 + +static int64_t opal_pci_phb_mmio_enable(uint64_t phb_id, uint16_t window_type, + uint16_t window_num, uint16_t enable) + +WARNING: following documentation is from old sources, and is possibly +not representative of OPALv3 as implemented by skiboot. This should be +used as a starting point for full documentation. + + +The host calls this function to enable or disable PHB decode of the PCI IO +and Memory address spaces below that PHB. Window_num selects an mmio window +within that addres space. Enable set to '1' enables the PHB to decode and +forward system real addresses to PCI memory, while enable set to '0' disables +PHB decode and forwarding for the address range defined in a particular MMIO +window. + +Not all PHB hardware may support disabling some or all MMIO windows. OPAL +returns OPAL_UNSUPPORTED if called to disable an MMIO window for which +hardware does not support disable. KVM may call this function for all MMIO +windows and ignore the opal_unsuppsorted return code so long as KVM has +disabled MMIO to all downstream PCI devices and assured that KVM and OS guest +partitions cannot issue CI loads/stores to these address spaces from the +processor (e.g.,via HPT). + +OPAL returns OPAL_SUCCESS for calls to OPAL to enable them for PHBs that do +not support disable. + + phb_id is the value from the PHB node ibm,opal-phbid property. + + window_type specifies 32-bit or 64-bit PCI memory + + '0' selects PCI IO Space + + '1' selects 32-bit PCI memory space + + '2' selects 64 bit PCI memory space + + window_num is the MMIO window number within the specified PCI memory space + + enable specifies to enable or disable this MMIO window. |