[qemu] Support SPI Console with TX indicator for QEMU #28770
+119
−18
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This is only enabled if the QEMU interface is configured for the SPI console - any other interface will retain the existing behaviour and avoid the additional poling from the host side. For QEMU specifically, we introduce a host-side poll to see the TX ready pin go low after reading out the header (but before reading out the payload). This ensures we don't run into synchronization issues due to emulation for very small SPI transfers in which the entirity of the header & payload are read out by the host before the device has a chance to run enough guest SW to signal that the GPIO ready pin should go low. In such a scenario, the device would look to host SW as if it is ready to send more data, even though in reality the guest SW has barely progressed enough to register that the host has started reading, causing the two devices to get out of sync. Signed-off-by: Alex Jones <[email protected]>
Includes fixes to the SPI device necessary to get the SPI console working when using the TX indicator GPIO, in addition to other new features and fixes (flash reads on unint flash, TPM hw registers, USB fixes and bus handling, etc.) Signed-off-by: Alex Jones <[email protected]>
Enables the `ottf_console_with_gpio_tx_indicator` test target for the QEMU execution environment, as this test exercises functionality that is required to be supported for provisioning flows. As QEMU does not currently implement the relevant Pinmux connections between OpenTitan and GPIO, a minor extension is made to the test to allow users to optionally specify which GPIO pin should be used as the ready-indicator, rather than hardcoding to IOA5. This is then overriden for the QEMU execution environment only. Signed-off-by: Alex Jones <[email protected]>
AlexJones0
force-pushed
the
qemu_spi_console_wait_tx
branch
from
333a622 to
a5651b6
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
To enable use of provisioning flows in QEMU, we need the ability to use the SPI console with the TX-ready indicator GPIO pin, as this console is widely used during the provisioning flows. The current implementation relies on synchronization logic with tight timing & ordering assumptions made for speed, which do not necessarily hold up in the emulated QEMU execution environment (see the commit messages & comments for more details).
This PR introduces an additional piece of synchronization to the TX ready pin which is only implemented for QEMU interfaces, and updates tests that use the SPI console to provide the correct interface (aside: maybe there is a nicer way to do this globally, rather than pass it in everywhere?) The QEMU version is then bumped to pull in some fixes to the SPI device that will allow this feature to work, and a relevant test
//sw/device/tests:ottf_console_with_gpio_tx_indicator_test_sim_qemu_rom_with_fake_keysis supported for testing this behaviour.