[spi_device] Add separate constraints for TPM and fast passthrough #21595
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Since generic mode has been removed, also remove SDCs related to it. Signed-off-by: Alexander Williams <[email protected]>
Create a separate timing for fast read commands for passthrough. The commands that use the fast read pipeline can have higher clock rates, while the combinatorial path cannot meet timing at those rates. Change the target for slow commands to 24 MHz, and target 33+ MHz for fast commands. The latter is currently overconstrained to 40 MHz. Signed-off-by: Alexander Williams <[email protected]>
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Related to the TPM CSB discussion: #21538 |
Create separate constraints for the TPM module. The TPM specification has some potentially more strict requirements for CSB on the device side than would be required for the SPI flash operations. Signed-off-by: Alexander Williams <[email protected]>
Relax timing requirements by selecting IOA7 as the sole pad required to meet timing for SPI Device's TPM mode CSB. Signed-off-by: Alexander Williams <[email protected]>
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Add constraints that are specific to TPM and fast passthrough commands. This might be excessive, but now there are five constraints modes:
We may be able to consolidate these, but we'll likely want to take a look at the data first.
In addition to the new constraint sets, some generic mode-specific exceptions get removed, and we select IOA7 as the only timed pad for SPI TPM's CSB. We should confirm that this is the correct chosen pad.
Finally, just a note, but for real synthesis, the pads should be set to the appropriate configuration to effect the intended data sheet. The defaults (e.g. minimum drive strength) will likely lead to very long pad delays used in analysis.