Documentation/hid/intel-ish-hid.rst

96 	| ISH Hardware/Firmware(FW) |
118 3.2.1 IPC/FW message types
172 Each FW client and a protocol is identified by a UUID. In order to communicate
173 to a FW client, a connection must be established using connect request and
182 the link will be dropped if major FW reset occurs.
191 Each side (host and FW) manages its DMA transfer memory independently. When an
192 ISHTP client from either host or FW side wants to send something, it decides
195 the respective host buffer (TX when host client sends, RX when FW client
200 (that includes RX buffer) and FW responds with DMA_ALLOC_NOTIFY_ACK.
202 if the host doesn't support DMA, then it won't send DMA allocation, so FW can't
203 send DMA; if FW doesn't support DMA then it won't respond with
206 it's request to do host->ISH DMA transfer; when FW sends DMA_XFER, it means
211 FW), DMA_XFER transfers ownership on the region that contains ISHTP message to
217 Currently, ISH FW decides to send over DMA if ISHTP message is more than 3 IPC
227 bus message protocol. These buffers are required because the FW may have not
234 The host enumeration bus command allows discovery of clients present in the FW.
244 - FW responds with HOST_START_RES_CMD
245 - Host sends HOST_ENUM_REQ_CMD (enumerate FW clients)
246 - FW responds with HOST_ENUM_RES_CMD that includes bitmap of available FW
248 - For each FW ID found in that bitmap host sends
250 - FW responds with HOST_CLIENT_PROPERTIES_RES_CMD. Properties include UUID,
262 - enumerate HID devices under FW ISH client