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OpenTitan: Add support for receiving data over the UART #1828

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merged 1 commit into from May 14, 2020
Merged

OpenTitan: Add support for receiving data over the UART #1828

merged 1 commit into from May 14, 2020

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alistair23
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Pull Request Overview

This PR adds support to the LowRISC UART driver to read data from the UART.

Testing Strategy

Tested by running the console_recv_short libtock-c example on the OpenTitan QEMU model and OpenTitan FPGA.

TODO or Help Wanted

Documentation Updated

  • Updated the relevant files in /docs, or no updates are required.

Formatting

  • Ran make formatall.

@alistair23 alistair23 added the WG-OpenTitan In the purview of the OpenTitan working group. label May 5, 2020
@bradjc
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bradjc commented May 5, 2020

It appears to be OK per the HIL to not wait until all the requested bytes are received, but the callback should return ESIZE in that case:

tock/kernel/src/hil/uart.rs

Lines 266 to 278 in 903b90c

/// The `rx_len` argument specifies how many words were transmitted.
/// An `rval` of SUCCESS indicates that every requested word was
/// received: `rx_len` in the callback should be the same as
/// `rx_len` in the initiating call.
///
/// `rval` is SUCCESS if the full buffer was successfully received, or
/// - ECANCEL if the call to `received_buffer` was cancelled and
/// the buffer was not fully received. `rx_len` contains
/// how many words were received.
/// - ESIZE if the buffer could only be partially received. `rx_len`
/// contains how many words were transmitted.
/// - FAIL if reception failed in some way: `error` may contain further
/// information.

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Updated

@alistair23
chips: lowrisc: uart: Add receive support
c194650 
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
bradjc
bradjc approved these changes May 12, 2020
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Didn't test, looks reasonable.

ppannuto
ppannuto approved these changes May 14, 2020
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bors d+

Deferring to OT-WG members to merge

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bors bot commented May 14, 2020

✌️ alistair23 can now approve this pull request. To approve and merge a pull request, simply reply with bors r+. More detailed instructions are available here.

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bors r+

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bors bot commented May 14, 2020

Build succeeded:

@bors bors bot merged commit cd0d123 into tock:master May 14, 2020
@alistair23 alistair23 deleted the alistair/opentitan-recv branch May 14, 2020 15:05
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@ppannuto ppannuto ppannuto approved these changes

@bradjc bradjc bradjc approved these changes

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