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271bc1eae6
These interfaces will be used by USART, USB and I2C stream drivers to provide a uniform interface for console mux'ing code. Signed-off-by: Anton Staaf <robotboy@chromium.org> BRANCH=None BUG=None TEST=make buildall -j Change-Id: If8938512c29708f7b8c28f6ca1c707aa6b5c1708 Reviewed-on: https://chromium-review.googlesource.com/216001 Reviewed-by: Randall Spangler <rspangler@chromium.org> Commit-Queue: Anton Staaf <robotboy@chromium.org> Tested-by: Anton Staaf <robotboy@chromium.org>
81 lines
2.8 KiB
C
81 lines
2.8 KiB
C
/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef INCLUDE_OUT_STREAM_H
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#define INCLUDE_OUT_STREAM_H
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#include <stddef.h>
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#include <stdint.h>
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struct out_stream;
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/*
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* An out_stream is a generic interface providing operations that can be used
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* to send a character stream over a USB endpoint, UART, I2C host interface, and
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* more. Each realization of an out_stream provides a constant instance of
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* the out_stream_ops structure that is used to operate on that realizations
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* out_streams. For example, the UART driver could provide one out_stream_ops
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* structure and four UART configs. Each UART config uses the same
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* out_stream_ops structure.
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*/
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struct out_stream_ops {
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/*
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* Write at most count characters from buffer into the output stream.
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* Return the number of characters actually written.
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*/
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size_t (*write)(struct out_stream const *stream,
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uint8_t const *buffer,
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size_t count);
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/*
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* Flush all outgoing data. This works if we are in an interrupt
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* context, or normal context. The call blocks until the output
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* stream is empty.
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*/
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void (*flush)(struct out_stream const *stream);
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};
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/*
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* The out_stream structure is embedded in the device configuration structure
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* that wishes to publish an out_stream capable interface. Uses of that device
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* can pass a pointer to the embedded out_stream around and use it like any
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* other out_stream.
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*/
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struct out_stream {
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/*
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* Ready will be called by the stream every time characters are removed
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* from the stream. This may be called from an interrupt context
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* so work done by the ready callback should be minimal. Likely this
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* callback will be used to call task_wake, or some similar signaling
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* mechanism.
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*
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* This callback is part of the user configuration of a stream, and not
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* a stream manipulation function (in_stream_ops). That means that
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* each stream can be configured with its own ready callback.
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*
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* If no callback functionality is required ready can be specified as
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* NULL.
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*/
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void (*ready)(struct out_stream const *stream);
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struct out_stream_ops const *ops;
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};
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/*
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* Helper functions that call the associated stream operation and pass it the
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* given stream. These help prevent mistakes where one stream is passed to
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* another stream's functions.
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*/
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size_t out_stream_write(struct out_stream const *stream,
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uint8_t const *buffer,
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size_t count);
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void out_stream_flush(struct out_stream const *stream);
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int out_stream_pause(struct out_stream const *stream);
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int out_stream_resume(struct out_stream const *stream);
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int out_stream_is_paused(struct out_stream const *stream);
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void out_stream_ready(struct out_stream const *stream);
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#endif /* INCLUDE_OUT_STREAM_H */
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