mirror of
https://git.proxmox.com/git/fwupd
synced 2025-06-29 21:37:58 +00:00
078beafb2d
It is far too easy to forget to set FWUPD_DEVICE_FLAG_NO_GUID_MATCHING for new
plugins, and without it it all works really well *until* a user has two devices
of the same type installed at the same time and then one 'disappears' for hard
to explain reasons. Typically we only need it for replug anyway!
Explicitly opt-in to this rarely-required behaviour, with the default to just
use the physical and logical IDs. Also document the update behavior for each
plugin to explain why the flag is being used.
This allows you to have two identical Unifying plugged in without one of them
being hidden from the user, at the same time allowing a HIDRAW<->USB transition
when going to and from bootloader and runtime modes.
This removes the workaround added in 99eb3f06b6.
Fixes https://github.com/fwupd/fwupd/issues/2915
115 lines
3.3 KiB
Markdown
115 lines
3.3 KiB
Markdown
Cypress support
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===============
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Introduction
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------------
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This plugin can flash firmware on Cypress CCGx USB-C controller family of
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devices used in docks.
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Supported Protocols
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-------------------
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This plugin supports the following protocol IDs:
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* com.cypress.ccgx
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* com.cypress.ccgx.dmc
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Device Flash
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============
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There are four kinds of flash layout. Single image firmware is not currently
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supported in this plugin.
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Symmetric Firmware
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------------------
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In symmetric firmware topology, FW1 and FW2 are both primary (main) firmware
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with identical sizes and functionality. We can only update FW1 from FW2 or FW2
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from FW1. This does mean we need to update just one time as booting from either
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firmware slot gives a fully functional device.
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After updating the "other" firmware we can just use `CY_PD_DEVICE_RESET_CMD_SIG`
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to reboot into the new firmware, and no further action is required.
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Asymmetric Firmware
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-------------------
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In asymmetric firmware topology, FW1 is backup and FW2 is primary (main)
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firmware with different firmware sizes. The backup firmware may not support all
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dock functionality.
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To update primary, we thus need to update twice:
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Case 1: FW2 is running
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* Update FW1 -> Jump to backup FW `CY_PD_JUMP_TO_ALT_FW_CMD_SIG` -> reboot
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* Update FW2 -> Reset device `CY_PD_DEVICE_RESET_CMD_SIG` -> reboot -> FW2
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Case 2: FW1 is running (recovery case)
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* Update FW2 -> Reset device `CY_PD_DEVICE_RESET_CMD_SIG` -> reboot -> FW2
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The `CY_PD_JUMP_TO_ALT_FW_CMD_SIG` command is allowed only in asymmetric FW, but
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`CY_PD_DEVICE_RESET_CMD_SIG` is allowed in both asymmetric FW and symmetric FW.
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DMC(Dock Management Controller) Composite Firmware
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--------------------------------------------------
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In composite firmware topology, a single firmware image contains metadata and
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firmware images of multiple devices including DMC itself in a dock system.
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Firmware Format
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===============
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There are two kinds of firmware format.
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Cyacd firmware format
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---------------------
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The daemon will decompress the cabinet archive and extract several firmware
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blobs in cyacd file format. See https://community.cypress.com/docs/DOC-10562
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for more details.
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DMC composite firmware format
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-----------------------------
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The daemon will decompress the cabinet archive and extract several firmware
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blobs in a combined image file format. See 4.4.1 Single Composite
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(Combined) Dock Image at https://www.cypress.com/file/387471/download
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for more details.
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GUID Generation
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---------------
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These devices use the standard USB DeviceInstanceId values, e.g.
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* `USB\VID_1234&PID_5678`
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Devices also have additional instance IDs which corresponds to the silicon ID,
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application ID and device mode, e.g.
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* `USB\VID_1234&PID_5678&SID_9ABC`
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* `USB\VID_1234&PID_5678&SID_9ABC&APP_DEF1`
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* `USB\VID_1234&PID_5678&SID_9ABC&APP_DEF1&MODE_FW2`
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Update Behavior
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---------------
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The device usually presents in runtime HID mode, but on detach re-enumerates
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with with a DMC or HPI interface. On attach the device again re-enumerates
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back to the runtime HID mode.
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For this reason the `REPLUG_MATCH_GUID` internal device flag is used so that
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the DMC/HPI and runtime modes are treated as the same device.
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Vendor ID Security
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------------------
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The vendor ID is set from the USB vendor, for example set to `USB:0x04B4`
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External interface access
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-------------------------
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This plugin requires read/write access to `/dev/bus/usb`.
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