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+/******************************************************************************
+*
+* Author: Xilinx, Inc.
+*
+*
+* This program is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License as published by the
+* Free Software Foundation; either version 2 of the License, or (at your
+* option) any later version.
+*
+*
+* XILINX IS PROVIDING THIS DESIGN, CODE, OR INFORMATION "AS IS" AS A
+* COURTESY TO YOU. BY PROVIDING THIS DESIGN, CODE, OR INFORMATION AS
+* ONE POSSIBLE IMPLEMENTATION OF THIS FEATURE, APPLICATION OR STANDARD,
+* XILINX IS MAKING NO REPRESENTATION THAT THIS IMPLEMENTATION IS FREE
+* FROM ANY CLAIMS OF INFRINGEMENT, AND YOU ARE RESPONSIBLE FOR OBTAINING
+* ANY THIRD PARTY RIGHTS YOU MAY REQUIRE FOR YOUR IMPLEMENTATION.
+* XILINX EXPRESSLY DISCLAIMS ANY WARRANTY WHATSOEVER WITH RESPECT TO
+* THE ADEQUACY OF THE IMPLEMENTATION, INCLUDING BUT NOT LIMITED TO ANY
+* WARRANTIES OR REPRESENTATIONS THAT THIS IMPLEMENTATION IS FREE FROM
+* CLAIMS OF INFRINGEMENT, IMPLIED WARRANTIES OF MERCHANTABILITY AND
+* FITNESS FOR A PARTICULAR PURPOSE.
+*
+*
+* Xilinx hardware products are not intended for use in life support
+* appliances, devices, or systems. Use in such applications is
+* expressly prohibited.
+*
+*
+* (c) Copyright 2002-2004 Xilinx Inc.
+* All rights reserved.
+*
+*
+* You should have received a copy of the GNU General Public License along
+* with this program; if not, write to the Free Software Foundation, Inc.,
+* 675 Mass Ave, Cambridge, MA 02139, USA.
+*
+* FILENAME:
+*
+* xdma_channel.h
+*
+* DESCRIPTION:
+*
+* This file contains the DMA channel component implementation. This component
+* supports a distributed DMA design in which each device can have it's own
+* dedicated DMA channel, as opposed to a centralized DMA design.
+* A device which uses DMA typically contains two DMA channels, one for
+* sending data and the other for receiving data.
+*
+* This component is designed to be used as a basic building block for
+* designing a device driver. It provides registers accesses such that all
+* DMA processing can be maintained easier, but the device driver designer
+* must still understand all the details of the DMA channel.
+*
+* The DMA channel allows a CPU to minimize the CPU interaction required to move
+* data between a memory and a device. The CPU requests the DMA channel to
+* perform a DMA operation and typically continues performing other processing
+* until the DMA operation completes. DMA could be considered a primitive form
+* of multiprocessing such that caching and address translation can be an issue.
+*
+* Scatter Gather Operations
+*
+* The DMA channel may support scatter gather operations. A scatter gather
+* operation automates the DMA channel such that multiple buffers can be
+* sent or received with minimal software interaction with the hardware. Buffer
+* descriptors, contained in the XBufDescriptor component, are used by the
+* scatter gather operations of the DMA channel to describe the buffers to be
+* processed.
+*
+* Scatter Gather List Operations
+*
+* A scatter gather list may be supported by each DMA channel. The scatter
+* gather list allows buffer descriptors to be put into the list by a device
+* driver which requires scatter gather. The hardware processes the buffer
+* descriptors which are contained in the list and modifies the buffer
+* descriptors to reflect the status of the DMA operations. The device driver
+* is notified by interrupt that specific DMA events occur including scatter
+* gather events. The device driver removes the completed buffer descriptors
+* from the scatter gather list to evaluate the status of each DMA operation.
+*
+* The scatter gather list is created and buffer descriptors are inserted into
+* the list. Buffer descriptors are never removed from the list after it's
+* creation such that a put operation copies from a temporary buffer descriptor
+* to a buffer descriptor in the list. Get operations don't copy from the list
+* to a temporary, but return a pointer to the buffer descriptor in the list.
+* A buffer descriptor in the list may be locked to prevent it from being
+* overwritten by a put operation. This allows the device driver to get a
+* descriptor from a scatter gather list and prevent it from being overwritten
+* until the buffer associated with the buffer descriptor has been processed.
+*
+* Typical Scatter Gather Processing
+*
+* The following steps illustrate the typical processing to use the
+* scatter gather features of a DMA channel.
+*
+* 1. Create a scatter gather list for the DMA channel which puts empty buffer
+* descriptors into the list.
+* 2. Create buffer descriptors which describe the buffers to be filled with
+* receive data or the buffers which contain data to be sent.
+* 3. Put buffer descriptors into the DMA channel scatter list such that scatter
+* gather operations are requested.
+* 4. Commit the buffer descriptors in the list such that they are ready to be
+* used by the DMA channel hardware.
+* 5. Start the scatter gather operations of the DMA channel.
+* 6. Process any interrupts which occur as a result of the scatter gather
+* operations or poll the DMA channel to determine the status.
+*
+* Interrupts
+*
+* Each DMA channel has the ability to generate an interrupt. This component
+* does not perform processing for the interrupt as this processing is typically
+* tightly coupled with the device which is using the DMA channel. It is the
+* responsibility of the caller of DMA functions to manage the interrupt
+* including connecting to the interrupt and enabling/disabling the interrupt.
+*
+* Critical Sections
+*
+* It is the responsibility of the device driver designer to use critical
+* sections as necessary when calling functions of the DMA channel. This
+* component does not use critical sections and it does access registers using
+* read-modify-write operations. Calls to DMA functions from a main thread
+* and from an interrupt context could produce unpredictable behavior such that
+* the caller must provide the appropriate critical sections.
+*
+* Address Translation
+*
+* All addresses of data structures which are passed to DMA functions must
+* be physical (real) addresses as opposed to logical (virtual) addresses.
+*
+* Caching
+*
+* The memory which is passed to the function which creates the scatter gather
+* list must not be cached such that buffer descriptors are non-cached. This
+* is necessary because the buffer descriptors are kept in a ring buffer and
+* not directly accessible to the caller of DMA functions.
+*
+* The caller of DMA functions is responsible for ensuring that any data
+* buffers which are passed to the DMA channel are cache-line aligned if
+* necessary.
+*
+* The caller of DMA functions is responsible for ensuring that any data
+* buffers which are passed to the DMA channel have been flushed from the cache.
+*
+* The caller of DMA functions is responsible for ensuring that the cache is
+* invalidated prior to using any data buffers which are the result of a DMA
+* operation.
+*
+* Memory Alignment
+*
+* The addresses of data buffers which are passed to DMA functions must be
+* 32 bit word aligned since the DMA hardware performs 32 bit word transfers.
+*
+* Mutual Exclusion
+*
+* The functions of the DMA channel are not thread safe such that the caller
+* of all DMA functions is responsible for ensuring mutual exclusion for a
+* DMA channel. Mutual exclusion across multiple DMA channels is not
+* necessary.
+*
+* NOTES:
+*
+* Many of the provided functions which are register accessors don't provide
+* a lot of error detection. The caller is expected to understand the impact
+* of a function call based upon the current state of the DMA channel. This
+* is done to minimize the overhead in this component.
+*
+******************************************************************************/
+
+#ifndef XDMA_CHANNEL_H /* prevent circular inclusions */
+#define XDMA_CHANNEL_H /* by using protection macros */
+
+/***************************** Include Files *********************************/
+
+#include "xdma_channel_i.h" /* constants shared with buffer descriptor */
+#include "xbasic_types.h"
+#include "xstatus.h"
+#include "xversion.h"
+#include "xbuf_descriptor.h"
+
+/************************** Constant Definitions *****************************/
+
+/* the following constants provide access to the bit fields of the DMA control
+ * register (DMACR)
+ */
+#define XDC_DMACR_SOURCE_INCR_MASK 0x80000000UL /* increment source address */
+#define XDC_DMACR_DEST_INCR_MASK 0x40000000UL /* increment dest address */
+#define XDC_DMACR_SOURCE_LOCAL_MASK 0x20000000UL /* local source address */
+#define XDC_DMACR_DEST_LOCAL_MASK 0x10000000UL /* local dest address */
+#define XDC_DMACR_SG_DISABLE_MASK 0x08000000UL /* scatter gather disable */
+#define XDC_DMACR_GEN_BD_INTR_MASK 0x04000000UL /* descriptor interrupt */
+#define XDC_DMACR_LAST_BD_MASK XDC_CONTROL_LAST_BD_MASK /* last buffer */
+ /* descriptor */
+
+/* the following constants provide access to the bit fields of the DMA status
+ * register (DMASR)
+ */
+#define XDC_DMASR_BUSY_MASK 0x80000000UL /* channel is busy */
+#define XDC_DMASR_BUS_ERROR_MASK 0x40000000UL /* bus error occurred */
+#define XDC_DMASR_BUS_TIMEOUT_MASK 0x20000000UL /* bus timeout occurred */
+#define XDC_DMASR_LAST_BD_MASK XDC_STATUS_LAST_BD_MASK /* last buffer */
+ /* descriptor */
+#define XDC_DMASR_SG_BUSY_MASK 0x08000000UL /* scatter gather is busy */
+
+/* the following constants provide access to the bit fields of the interrupt
+ * status register (ISR) and the interrupt enable register (IER), bit masks
+ * match for both registers such that they are named IXR
+ */
+#define XDC_IXR_DMA_DONE_MASK 0x1UL /* dma operation done */
+#define XDC_IXR_DMA_ERROR_MASK 0x2UL /* dma operation error */
+#define XDC_IXR_PKT_DONE_MASK 0x4UL /* packet done */
+#define XDC_IXR_PKT_THRESHOLD_MASK 0x8UL /* packet count threshold */
+#define XDC_IXR_PKT_WAIT_BOUND_MASK 0x10UL /* packet wait bound reached */
+#define XDC_IXR_SG_DISABLE_ACK_MASK 0x20UL /* scatter gather disable
+ acknowledge occurred */
+#define XDC_IXR_SG_END_MASK 0x40UL /* last buffer descriptor
+ disabled scatter gather */
+#define XDC_IXR_BD_MASK 0x80UL /* buffer descriptor done */
+
+/**************************** Type Definitions *******************************/
+
+/*
+ * the following structure contains data which is on a per instance basis
+ * for the XDmaChannel component
+ */
+typedef struct XDmaChannelTag {
+ XVersion Version; /* version of the driver */
+ u32 RegBaseAddress; /* base address of registers */
+ u32 IsReady; /* device is initialized and ready */
+
+ XBufDescriptor *PutPtr; /* keep track of where to put into list */
+ XBufDescriptor *GetPtr; /* keep track of where to get from list */
+ XBufDescriptor *CommitPtr; /* keep track of where to commit in list */
+ XBufDescriptor *LastPtr; /* keep track of the last put in the list */
+ u32 TotalDescriptorCount; /* total # of descriptors in the list */
+ u32 ActiveDescriptorCount; /* # of descriptors pointing to buffers
+ * in the buffer descriptor list */
+} XDmaChannel;
+
+/***************** Macros (Inline Functions) Definitions *********************/
+
+/************************** Function Prototypes ******************************/
+
+XStatus XDmaChannel_Initialize(XDmaChannel * InstancePtr, u32 BaseAddress);
+u32 XDmaChannel_IsReady(XDmaChannel * InstancePtr);
+XVersion *XDmaChannel_GetVersion(XDmaChannel * InstancePtr);
+XStatus XDmaChannel_SelfTest(XDmaChannel * InstancePtr);
+void XDmaChannel_Reset(XDmaChannel * InstancePtr);
+
+/* Control functions */
+
+u32 XDmaChannel_GetControl(XDmaChannel * InstancePtr);
+void XDmaChannel_SetControl(XDmaChannel * InstancePtr, u32 Control);
+
+/* Status functions */
+
+u32 XDmaChannel_GetStatus(XDmaChannel * InstancePtr);
+void XDmaChannel_SetIntrStatus(XDmaChannel * InstancePtr, u32 Status);
+u32 XDmaChannel_GetIntrStatus(XDmaChannel * InstancePtr);
+void XDmaChannel_SetIntrEnable(XDmaChannel * InstancePtr, u32 Enable);
+u32 XDmaChannel_GetIntrEnable(XDmaChannel * InstancePtr);
+
+/* DMA without scatter gather functions */
+
+void XDmaChannel_Transfer(XDmaChannel * InstancePtr,
+ u32 * SourcePtr, u32 * DestinationPtr, u32 ByteCount);
+
+/* Scatter gather functions */
+
+XStatus XDmaChannel_SgStart(XDmaChannel * InstancePtr);
+XStatus XDmaChannel_SgStop(XDmaChannel * InstancePtr,
+ XBufDescriptor ** BufDescriptorPtr);
+XStatus XDmaChannel_CreateSgList(XDmaChannel * InstancePtr,
+ u32 * MemoryPtr, u32 ByteCount);
+u32 XDmaChannel_IsSgListEmpty(XDmaChannel * InstancePtr);
+
+XStatus XDmaChannel_PutDescriptor(XDmaChannel * InstancePtr,
+ XBufDescriptor * BufDescriptorPtr);
+XStatus XDmaChannel_CommitPuts(XDmaChannel * InstancePtr);
+XStatus XDmaChannel_GetDescriptor(XDmaChannel * InstancePtr,
+ XBufDescriptor ** BufDescriptorPtr);
+
+/* Packet functions for interrupt collescing */
+
+u32 XDmaChannel_GetPktCount(XDmaChannel * InstancePtr);
+void XDmaChannel_DecrementPktCount(XDmaChannel * InstancePtr);
+XStatus XDmaChannel_SetPktThreshold(XDmaChannel * InstancePtr, u8 Threshold);
+u8 XDmaChannel_GetPktThreshold(XDmaChannel * InstancePtr);
+void XDmaChannel_SetPktWaitBound(XDmaChannel * InstancePtr, u32 WaitBound);
+u32 XDmaChannel_GetPktWaitBound(XDmaChannel * InstancePtr);
+
+#endif /* end of protection macro */