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/* Copyright 2013 The ChromiumOS Authors
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* DMA interface
*/
#ifndef __CROS_EC_DMA_H
#define __CROS_EC_DMA_H
#ifdef CONFIG_DMA
#include "common.h"
#include "registers.h"
#include <stdbool.h>
/* DMA channel options */
struct dma_option {
enum dma_channel channel; /* DMA channel */
void *periph; /* Pointer to peripheral data register */
unsigned flags; /* DMA flags for the control register. Normally
used to select memory size. */
};
#define DMA_POLLING_INTERVAL_US 100 /* us */
#define DMA_TRANSFER_TIMEOUT_US (100 * MSEC) /* us */
/**
* Get a pointer to a DMA channel.
*
* @param channel Channel to read
* @return pointer to DMA channel registers
*/
dma_chan_t *dma_get_channel(enum dma_channel channel);
/**
* Prepare a DMA transfer to transmit data from memory to a peripheral
*
* Call dma_go() afterwards to actually start the transfer.
*
* @param option DMA channel options
* @param count Number of bytes to transfer
* @param memory Pointer to memory address
*
* @return pointer to prepared channel
*/
void dma_prepare_tx(const struct dma_option *option, unsigned count,
const void *memory);
/**
* Start a DMA transfer to receive data to memory from a peripheral
*
* @param option DMA channel options
* @param count Number of bytes to transfer
* @param memory Pointer to memory address
*/
void dma_start_rx(const struct dma_option *option, unsigned count,
void *memory);
/**
* Stop a DMA transfer on a channel
*
* Disable the DMA channel and immediate stop all transfers on it.
*
* @param channel Channel to stop
*/
void dma_disable(enum dma_channel channel);
/* Stop transfers on all DMA channels */
void dma_disable_all(void);
/**
* Get the number of bytes available to read, or number of bytes written
*
* Since the DMA controller counts downwards, if we know the starting value
* we can work out how many bytes have been completed so far.
*
* @param chan DMA channel to check, from dma_get_channel()
* @param orig_count Original number of bytes requested on channel
* @return number of bytes completed on a channel
*/
int dma_bytes_done(dma_chan_t *chan, int orig_count);
/**
* Check if DMA for a given channel is enabled.
*
* @param chan DMA channel to check, from dma_get_channel()
* @return true if DMA is enabled on the channel, false otherwise
*/
bool dma_is_enabled(dma_chan_t *chan);
/**
* Start a previously-prepared dma channel
*
* @param chan Channel to start, from dma_get_channel()
*/
void dma_go(dma_chan_t *chan);
#ifdef CONFIG_DMA_HELP
/**
* Testing: Print out the data transferred by a channel
*
* @param channel Channel to read
* @param buff Start of DMA buffer
*/
void dma_check(enum dma_channel channel, char *buf);
/**
* Dump out imformation about a dma channel
*
* @param channel Channel to read
*/
void dma_dump(enum dma_channel channel);
/**
* Testing: Test that DMA works correctly for memory to memory transfers
*/
void dma_test(enum dma_channel channel);
#endif /* CONFIG_DMA_HELP */
/**
* Clear the DMA interrupt/event flags for a given channel
*
* @param channel Which channel's isr to clear
*/
void dma_clear_isr(enum dma_channel channel);
/**
* Enable "Transfer Complete" interrupt for a DMA channel.
* Will Wake up calling task when complete.
*
* @param channel Which channel's interrupts to change
*/
void dma_enable_tc_interrupt(enum dma_channel channel);
/**
* Enable "Transfer Complete" interrupt for a DMA channel with callback
* NOTE: The callback is run at highest interrupt priority so should be
* fast and not depend on get_time().
*
* @param channel Which channel's interrupts to change
* @param callback Pointer to callback function to call on interrupt
* @param callback_data Data to pass through to callback function
*/
void dma_enable_tc_interrupt_callback(enum dma_channel channel,
void (*callback)(void *),
void *callback_data);
/**
* Disable "Transfer Complete" interrupt for a DMA channel
*
* @param channel Which channel's interrupts to change
*/
void dma_disable_tc_interrupt(enum dma_channel channel);
/**
* Wait for the DMA transfer to complete by polling the transfer complete flag
*
* @param channel Channel number to wait on
* @return EC_ERROR_TIMEOUT for timeout, EC_SUCCESS for success
*/
int dma_wait(enum dma_channel channel);
/**
* Initialize the DMA module.
*/
void dma_init(void);
#endif /* CONFIG_DMA */
#endif
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