P4 fixes

resources/espressif__esp_hosted/docs/wifi_design.md

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+# ESP-Hosted-MCU Wi-Fi Design & Implementation details
+
+
+## Sequence Diagram for Wi-Fi communication
+
+On a ESP chipset with native Wi-Fi, a Wi-Fi api call or network data
+from the application is processed internally on the chip and a Wi-Fi
+response is returned to the application.
+
+```mermaid
+sequenceDiagram
+    box rgb(128, 128, 128) Host With Native WI-Fi
+    participant app as Application
+    participant api as ESP-IDF Wi-Fi Library
+    participant wifi as Wi-Fi Hardware
+    end
+
+    app ->> api : esp_wifi_xxx() or Network Data
+    api ->> wifi : 
+    Note over wifi : Do Wi-Fi action
+    wifi -->> api : Wi-Fi response or Data
+    api -->> app : Response or Network Data
+```
+
+Using Wi-Remote and ESP-Hosted, the Wi-Fi api call from the
+application is converted into a Hosted Call and transported to the
+slave. The slave converts the Hosted Call back into an Wi-Fi api
+call. The response (optionally with data) is converted into a Hosted
+Response and transported back to the host. On the host, the Hosted
+Response is converted back into a Wi-Fi response (optionally with
+data) is returned to the application.
+
+For Network Data, Hosted does not do data conversion and only
+encapsulates the data for transport.
+
+```mermaid
+sequenceDiagram
+    box rgb(128, 128, 128) Host with ESP-Hosted
+    participant app as Application
+    participant remote as Wi-Fi Remote
+    participant hostedh as ESP-Hosted
+    participant transporth as Host Transport
+    end
+
+    box rgb(128, 128, 128) Slave ESP-Hosted
+    participant transports as Slave Transport
+    participant hosteds as Slave Hosted
+    participant api as ESP-IDF Wi-Fi Library
+    participant wifi as Wi-Fi Hardware
+    end
+
+    app ->> remote : esp_wifi_xxx()
+    remote ->> hostedh : esp_wifi_remote_xxx()
+    app ->> hostedh : Network Data
+    Note over hostedh : add Hosted header
+    hostedh ->> transporth : 
+
+    transporth ->> transports : SPI/SDIO
+
+    transports ->> hosteds : 
+    Note over hosteds : remove Hosted header
+    hosteds ->> api : esp_wifi_xxx()
+    hosteds ->> wifi : Network Data
+    api ->> wifi : Wi-Fi command or Data
+    Note over wifi: Do Wi-Fi action
+    wifi -->> api : Wi-Fi response or Data
+    wifi -->> hosteds : Network Data
+    api -->> hosteds : Response
+    Note over hosteds : add Hosted header
+    hosteds -->> transports : 
+
+    transports -->> transporth : SPI/SDIO
+
+    transporth -->> hostedh : 
+    Note over hostedh : remove Hosted header
+    hostedh -->> app : Network Data
+    hostedh -->> remote : Wi-Fi Command response
+    remote -->> app : Response
+```