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1.1 root 1: /*
2: * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
3: *
4: * @APPLE_LICENSE_HEADER_START@
5: *
6: * The contents of this file constitute Original Code as defined in and
7: * are subject to the Apple Public Source License Version 1.1 (the
8: * "License"). You may not use this file except in compliance with the
9: * License. Please obtain a copy of the License at
10: * http://www.apple.com/publicsource and read it before using this file.
11: *
12: * This Original Code and all software distributed under the License are
13: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
14: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
15: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
16: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
17: * License for the specific language governing rights and limitations
18: * under the License.
19: *
20: * @APPLE_LICENSE_HEADER_END@
21: */
22: #ifndef _IOMEMORYCURSOR_H
23: #define _IOMEMORYCURSOR_H
24:
25: #include <libkern/c++/OSObject.h>
26: #include <IOKit/IOTypes.h>
27:
28: class IOMemoryDescriptor;
29:
30: /**************************** class IOMemoryCursor ***************************/
31:
32: /*!
33: @class IOMemoryCursor : public OSObject
34: @abstract A mechanism to convert memory references to physical addresses.
35: @discussion The IOMemoryCursor declares the super class that all
36: specific memory cursors must inherit from, but a memory cursor can be created without a specific format subclass by just providing a segment function to the initializers. This class does the difficult stuff of dividing a memory descriptor into a physical scatter/gather list appropriate for the target hardware.
37: <br><br>
38: A driver is expected to create a memory cursor and configure it to the limitations of it's DMA hardware; for instance the memory cursor used by the firewire SBP2 protocol has a maximum physical segment size of 2^16 - 1 but the actual transfer size is unlimited. Thus it would create a cursor with a maxSegmentSize of 65535 and a maxTransfer size of UINT_MAX. It would also provide a SegmentFunction that can output a pagelist entry.
39: <br><br>
40: Below is the simplest example of a SegmentFunction:-
41: void IONaturalMemoryCursor::outputSegment(PhysicalSegment segment,
42: void * outSegments,
43: UInt32 outSegmentIndex)
44: {
45: ((PhysicalSegment *) outSegments)[outSegmentIndex] = segment;
46: }
47:
48: */
49: class IOMemoryCursor : public OSObject
50: {
51: OSDeclareDefaultStructors(IOMemoryCursor)
52:
53: public:
54: /*!
55: @typedef PhysicalSegment
56: @discussion A physical address/length pair.
57: */
58: struct PhysicalSegment
59: {
60: IOPhysicalAddress location;
61: IOPhysicalLength length;
62: };
63:
64: /*! @defined IOPhysicalSegment
65: @discussion Backward compatibilty define for the old non-class scoped type definition. See $link IOMemoryCursor::PhysicalSegment */
66: #define IOPhysicalSegment IOMemoryCursor::PhysicalSegment
67:
68: /*!
69: @typedef SegmentFunction
70: @discussion Pointer to a C function that outputs a single physical segment to an element in the array as defined by the segments and segmentIndex parameters.
71: @param segment The physical address and length that is next to be output.
72: @param segments Base of the output vector of DMA address length pairs.
73: @param segmentIndex Index to output 'segment' in the 'segments' array.
74: */
75: typedef void (*SegmentFunction)(PhysicalSegment segment,
76: void * segments,
77: UInt32 segmentIndex);
78:
79: /*! @defined OutputSegmentFunc
80: @discussion Backward compatibilty define for the old non-class scoped type definition. See $link IOMemoryCursor::SegmentFunction */
81: #define OutputSegmentFunc IOMemoryCursor::SegmentFunction
82:
83: protected:
84: /*! @var outSeg The action method called when an event has been delivered */
85: SegmentFunction outSeg;
86:
87: /*! @var maxSegmentSize Maximum size of one segment in a scatter/gather list */
88: IOPhysicalLength maxSegmentSize;
89:
90: /*! @var maxTransferSize
91: Maximum size of a transfer that this memory cursor is allowed to generate */
92: IOPhysicalLength maxTransferSize;
93:
94: /*! @var alignMask
95: Currently unused. Reserved for automated aligment restriction code. */
96: IOPhysicalLength alignMask;
97:
98: public:
99: /*! @function withSpecification
100: @abstract Factory function to create and initialise an IOMemoryCursor in one operation, see $link IOMemoryCursor::initWithSpecification.
101: @param outSegFunc SegmentFunction to call to output one physical segment.
102: @param maxSegmentSize Maximum allowable size for one segment. Defaults to 0.
103: @param maxTransferSize Maximum size of an entire transfer. Default to 0 indicating no maximum.
104: @param alignment Alligment restrictions on output physical addresses. Not currently implemented. Defaults to single byte alignment.
105: @result A new memory cursor if successfully created and initialised, 0 otherwise.
106: */
107: static IOMemoryCursor *
108: withSpecification(SegmentFunction outSegFunc,
109: IOPhysicalLength maxSegmentSize = 0,
110: IOPhysicalLength maxTransferSize = 0,
111: IOPhysicalLength alignment = 1);
112:
113: /*! @function initWithSpecification
114: @abstract Primary initialiser for the IOMemoryCursor class.
115: @param outSegFunc SegmentFunction to call to output one physical segment.
116: @param maxSegmentSize Maximum allowable size for one segment. Defaults to 0.
117: @param maxTransferSize Maximum size of an entire transfer. Default to 0 indicating no maximum.
118: @param alignment Alligment restrictions on output physical addresses. Not currently implemented. Defaults to single byte alignment.
119: @result true if the inherited classes and this instance initialise
120: successfully.
121: */
122: virtual bool initWithSpecification(SegmentFunction outSegFunc,
123: IOPhysicalLength maxSegmentSize = 0,
124: IOPhysicalLength maxTransferSize = 0,
125: IOPhysicalLength alignment = 1);
126:
127: /*! @function genPhysicalSegments
128: @abstract Generate a physical scatter/gather list given a memory descriptor.
129: @discussion Generates a list of physical segments from the given memory descriptor, relative to the current position of the descriptor.
130: @param descriptor IOMemoryDescriptor that describes the data associated with an I/O request.
131: @param fromPosition Starting location of the I/O within a memory descriptor.
132: @param segments Void pointer to base of output physical scatter/gather list. Always passed directly onto the SegmentFunction without interpretation by the cursor.
133: @param maxSegments Maximum number of segments that can be written to segments array.
134: @param maxTransferSize Maximum transfer size is limited to that many bytes, otherwise it defaults to the maximum transfer size specified when the memory cursor was initialized.
135: @param transferSize Pointer to a IOByteCount variable that can contain the total size of the transfer being described. Default to 0 indicating that no transfer size need be returned.
136: @result If the descriptor is exhausted of memory, a zero is returned, otherwise the number of segments that were filled in is returned.
137: */
138: virtual UInt32 genPhysicalSegments(
139: IOMemoryDescriptor *descriptor,
140: IOByteCount fromPosition,
141: void * segments,
142: UInt32 maxSegments,
143: UInt32 maxTransferSize = 0,
144: IOByteCount *transferSize = 0);
145: };
146:
147: /************************ class IONaturalMemoryCursor ************************/
148:
149:
150: /*!
151: @class IONaturalMemoryCursor : public IOMemoryCursor
152: @abstract A $link IOMemoryCursor subclass that outputs a vector of PhysicalSegments in the natural byte orientation for the cpu.
153: @discussion The IONaturalMemoryCursor would be used when it is too difficult to safely describe a SegmentFunction that is more appropriate for your hardware. This cursor just outputs an array of PhysicalSegments.
154: */
155: class IONaturalMemoryCursor : public IOMemoryCursor
156: {
157: OSDeclareDefaultStructors(IONaturalMemoryCursor)
158:
159: public:
160: /*! @funtion outputSegment
161: @abstract Output the given segment into the output segments array in natural byte order.
162: @param segment The physical address and length that is next to be output.
163: @param segments Base of the output vector of DMA address length pairs.
164: @param segmentIndex Index to output 'segment' in the 'segments' array.
165: */
166: static void outputSegment(PhysicalSegment segment,
167: void * segments,
168: UInt32 segmentIndex);
169:
170: /*! @defined naturalOutputSegment
171: @discussion Backward compatibilty define for the old global function definition. See $link IONaturalMemoryCursor::outputSegment */
172: #define naturalOutputSegment IONaturalMemoryCursor::outputSegment
173:
174: /*! @function withSpecification
175: @abstract Factory function to create and initialise an IONaturalMemoryCursor in one operation, see $link IONaturalMemoryCursor::initWithSpecification.
176: @param maxSegmentSize Maximum allowable size for one segment. Defaults to 0.
177: @param maxTransferSize Maximum size of an entire transfer. Default to 0 indicating no maximum.
178: @param alignment Alligment restrictions on output physical addresses. Not currently implemented. Defaults to single byte alignment.
179: @result A new memory cursor if successfully created and initialised, 0 otherwise.
180: */
181: static IONaturalMemoryCursor *
182: withSpecification(IOPhysicalLength maxSegmentSize,
183: IOPhysicalLength maxTransferSize,
184: IOPhysicalLength alignment = 1);
185:
186: /*! @function initWithSpecification
187: @abstract Primary initialiser for the IONaturalMemoryCursor class.
188: @param maxSegmentSize Maximum allowable size for one segment. Defaults to 0.
189: @param maxTransferSize Maximum size of an entire transfer. Default to 0 indicating no maximum.
190: @param alignment Alligment restrictions on output physical addresses. Not currently implemented. Defaults to single byte alignment.
191: @result true if the inherited classes and this instance initialise
192: successfully.
193: */
194: virtual bool initWithSpecification(IOPhysicalLength maxSegmentSize,
195: IOPhysicalLength maxTransferSize,
196: IOPhysicalLength alignment = 1);
197:
198:
199: /*! @function getPhysicalSegments
200: @abstract Generate a cpu natural physical scatter/gather list given a memory descriptor.
201: @discussion Generates a list of physical segments from the given memory descriptor, relative to the current position of the descriptor. Wraps $link IOMemoryCursor::genPhysicalSegments.
202: @param descriptor IOMemoryDescriptor that describes the data associated with an I/O request.
203: @param fromPosition Starting location of the I/O within a memory descriptor.
204: @param segments Pointer to an array of $link IOMemoryCursor::PhysicalSegments for the output physical scatter/gather list.
205: @param maxSegments Maximum number of segments that can be written to segments array.
206: @param maxTransferSize Maximum transfer size is limited to that many bytes, otherwise it defaults to the maximum transfer size specified when the memory cursor was initialized.
207: @param transferSize Pointer to a IOByteCount variable that can contain the total size of the transfer being described. Default to 0 indicating that no transfer size need be returned.
208: @result If the descriptor is exhausted of memory, a zero is returned, otherwise the number of segments that were filled in is returned.
209: */
210: virtual UInt32 getPhysicalSegments(IOMemoryDescriptor *descriptor,
211: IOByteCount fromPosition,
212: PhysicalSegment *segments,
213: UInt32 maxSegments,
214: UInt32 maxTransferSize = 0,
215: IOByteCount *transferSize = 0)
216: {
217: return genPhysicalSegments(descriptor, fromPosition, segments,
218: maxSegments, maxTransferSize, transferSize);
219: }
220: };
221:
222: /************************** class IOBigMemoryCursor **************************/
223:
224: /*!
225: @class IOBigMemoryCursor : public IOMemoryCursor
226: @abstract A $link IOMemoryCursor subclass that outputs a vector of PhysicalSegments in the big endian byte order.
227: @discussion The IOBigMemoryCursor would be used when the DMA hardware requires a big endian address and length pair. This cursor outputs an array of PhysicalSegments that are encoded in big-endian format.
228: */
229: class IOBigMemoryCursor : public IOMemoryCursor
230: {
231: OSDeclareDefaultStructors(IOBigMemoryCursor)
232:
233: public:
234: /*! @funtion outputSegment
235: @abstract Output the given segment into the output segments array in big endian byte order.
236: @param segment The physical address and length that is next to be output.
237: @param segments Base of the output vector of DMA address length pairs.
238: @param segmentIndex Index to output 'segment' in the 'segments' array.
239: */
240: static void outputSegment(PhysicalSegment segment,
241: void * segments,
242: UInt32 segmentIndex);
243:
244: /*! @defined bigOutputSegment
245: @discussion Backward compatibilty define for the old global function definition. See $link IOBigMemoryCursor::outputSegment */
246: #define bigOutputSegment IOBigMemoryCursor::outputSegment
247:
248: /*! @function withSpecification
249: @abstract Factory function to create and initialise an IOBigMemoryCursor in one operation, see $link IOBigMemoryCursor::initWithSpecification.
250: @param maxSegmentSize Maximum allowable size for one segment. Defaults to 0.
251: @param maxTransferSize Maximum size of an entire transfer. Default to 0 indicating no maximum.
252: @param alignment Alligment restrictions on output physical addresses. Not currently implemented. Defaults to single byte alignment.
253: @result A new memory cursor if successfully created and initialised, 0 otherwise.
254: */
255: static IOBigMemoryCursor *
256: withSpecification(IOPhysicalLength maxSegmentSize,
257: IOPhysicalLength maxTransferSize,
258: IOPhysicalLength alignment = 1);
259:
260: /*! @function initWithSpecification
261: @abstract Primary initialiser for the IOBigMemoryCursor class.
262: @param maxSegmentSize Maximum allowable size for one segment. Defaults to 0.
263: @param maxTransferSize Maximum size of an entire transfer. Default to 0 indicating no maximum.
264: @param alignment Alligment restrictions on output physical addresses. Not currently implemented. Defaults to single byte alignment.
265: @result true if the inherited classes and this instance initialise
266: successfully.
267: */
268: virtual bool initWithSpecification(IOPhysicalLength maxSegmentSize,
269: IOPhysicalLength maxTransferSize,
270: IOPhysicalLength alignment = 1);
271:
272:
273: /*! @function getPhysicalSegments
274: @abstract Generate a big endian physical scatter/gather list given a memory descriptor.
275: @discussion Generates a list of physical segments from the given memory descriptor, relative to the current position of the descriptor. Wraps $link IOMemoryCursor::genPhysicalSegments.
276: @param descriptor IOMemoryDescriptor that describes the data associated with an I/O request.
277: @param fromPosition Starting location of the I/O within a memory descriptor.
278: @param segments Pointer to an array of $link IOMemoryCursor::PhysicalSegments for the output physical scatter/gather list.
279: @param maxSegments Maximum number of segments that can be written to segments array.
280: @param maxTransferSize Maximum transfer size is limited to that many bytes, otherwise it defaults to the maximum transfer size specified when the memory cursor was initialized.
281: @param transferSize Pointer to a IOByteCount variable that can contain the total size of the transfer being described. Default to 0 indicating that no transfer size need be returned.
282: @result If the descriptor is exhausted of memory, a zero is returned, otherwise the number of segments that were filled in is returned.
283: */
284: virtual UInt32 getPhysicalSegments(IOMemoryDescriptor * descriptor,
285: IOByteCount fromPosition,
286: PhysicalSegment * segments,
287: UInt32 maxSegments,
288: UInt32 maxTransferSize = 0,
289: IOByteCount * transferSize = 0)
290: {
291: return genPhysicalSegments(descriptor, fromPosition, segments,
292: maxSegments, maxTransferSize, transferSize);
293: }
294: };
295:
296: /************************* class IOLittleMemoryCursor ************************/
297:
298: /*!
299: @class IOLittleMemoryCursor : public IOMemoryCursor
300: @abstract A $link IOMemoryCursor subclass that outputs a vector of PhysicalSegments in the little endian byte order.
301: @discussion The IOLittleMemoryCursor would be used when the DMA hardware requires a little endian address and length pair. This cursor outputs an array of PhysicalSegments that are encoded in little endian format.
302: */
303: class IOLittleMemoryCursor : public IOMemoryCursor
304: {
305: OSDeclareDefaultStructors(IOLittleMemoryCursor)
306:
307: public:
308: /*! @funtion outputSegment
309: @abstract Output the given segment into the output segments array in little endian byte order.
310: @param segment The physical address and length that is next to be output.
311: @param segments Base of the output vector of DMA address length pairs.
312: @param segmentIndex Index to output 'segment' in the 'segments' array.
313: */
314: static void outputSegment(PhysicalSegment segment,
315: void * segments,
316: UInt32 segmentIndex);
317:
318: /*! @defined littleOutputSegment
319: @discussion Backward compatibilty define for the old global function definition. See $link IOLittleMemoryCursor::outputSegment */
320: #define littleOutputSegment IOLittleMemoryCursor::outputSegment
321:
322: /*! @function withSpecification
323: @abstract Factory function to create and initialise an IOLittleMemoryCursor in one operation, see $link IOLittleMemoryCursor::initWithSpecification.
324: @param maxSegmentSize Maximum allowable size for one segment. Defaults to 0.
325: @param maxTransferSize Maximum size of an entire transfer. Default to 0 indicating no maximum.
326: @param alignment Alligment restrictions on output physical addresses. Not currently implemented. Defaults to single byte alignment.
327: @result A new memory cursor if successfully created and initialised, 0 otherwise.
328: */
329: static IOLittleMemoryCursor *
330: withSpecification(IOPhysicalLength maxSegmentSize,
331: IOPhysicalLength maxTransferSize,
332: IOPhysicalLength alignment = 1);
333:
334: /*! @function initWithSpecification
335: @abstract Primary initialiser for the IOLittleMemoryCursor class.
336: @param maxSegmentSize Maximum allowable size for one segment. Defaults to 0.
337: @param maxTransferSize Maximum size of an entire transfer. Default to 0 indicating no maximum.
338: @param alignment Alligment restrictions on output physical addresses. Not currently implemented. Defaults to single byte alignment.
339: @result true if the inherited classes and this instance initialise
340: successfully.
341: */
342: virtual bool initWithSpecification(IOPhysicalLength maxSegmentSize,
343: IOPhysicalLength maxTransferSize,
344: IOPhysicalLength alignment = 1);
345:
346:
347: /*! @function getPhysicalSegments
348: @abstract Generate a little endian physical scatter/gather list given a memory descriptor.
349: @discussion Generates a list of physical segments from the given memory descriptor, relative to the current position of the descriptor. Wraps $link IOMemoryCursor::genPhysicalSegments.
350: @param descriptor IOMemoryDescriptor that describes the data associated with an I/O request.
351: @param fromPosition Starting location of the I/O within a memory descriptor.
352: @param segments Pointer to an array of $link IOMemoryCursor::PhysicalSegments for the output physical scatter/gather list.
353: @param maxSegments Maximum number of segments that can be written to segments array.
354: @param maxTransferSize Maximum transfer size is limited to that many bytes, otherwise it defaults to the maximum transfer size specified when the memory cursor was initialized.
355: @param transferSize Pointer to a IOByteCount variable that can contain the total size of the transfer being described. Default to 0 indicating that no transfer size need be returned.
356: @result If the descriptor is exhausted of memory, a zero is returned, otherwise the number of segments that were filled in is returned.
357: */
358: virtual UInt32 getPhysicalSegments(IOMemoryDescriptor * descriptor,
359: IOByteCount fromPosition,
360: PhysicalSegment * segments,
361: UInt32 maxSegments,
362: UInt32 maxTransferSize = 0,
363: IOByteCount * transferSize = 0)
364: {
365: return genPhysicalSegments(descriptor, fromPosition, segments,
366: maxSegments, maxTransferSize, transferSize);
367: }
368: };
369:
370: /************************* class IODBDMAMemoryCursor *************************/
371:
372: #if defined(__ppc__)
373:
374: struct IODBDMADescriptor;
375:
376: /*!
377: @class IODBDMAMemoryCursor : public IOMemoryCursor
378: @abstract A $link IOMemoryCursor subclass that outputs a vector of DBDMA descriptors where the address and length are filled in.
379: @discussion The IODBDMAMemoryCursor would be used when the DBDMA hardware is available for the device for that will use an instance of this cursor.
380: */
381: class IODBDMAMemoryCursor : public IOMemoryCursor
382: {
383: OSDeclareDefaultStructors(IODBDMAMemoryCursor)
384:
385: public:
386: /*! @funtion outputSegment
387: @abstract Output the given segment into the output segments array in address and length fields of an DBDMA descriptor.
388: @param segment The physical address and length that is next to be output.
389: @param segments Base of the output vector of DMA address length pairs.
390: @param segmentIndex Index to output 'segment' in the 'segments' array.
391: */
392: static void outputSegment(PhysicalSegment segment,
393: void * segments,
394: UInt32 segmentIndex);
395:
396: /*! @defined dbdmaOutputSegment
397: @discussion Backward compatibilty define for the old global function definition. See $link IODBDMAMemoryCursor::outputSegment */
398: #define dbdmaOutputSegment IODBDMAMemoryCursor::outputSegment
399:
400: /*! @function withSpecification
401: @abstract Factory function to create and initialise an IODBDMAMemoryCursor in one operation, see $link IODBDMAMemoryCursor::initWithSpecification.
402: @param maxSegmentSize Maximum allowable size for one segment. Defaults to 0.
403: @param maxTransferSize Maximum size of an entire transfer. Default to 0 indicating no maximum.
404: @param alignment Alligment restrictions on output physical addresses. Not currently implemented. Defaults to single byte alignment.
405: @result A new memory cursor if successfully created and initialised, 0 otherwise.
406: */
407: static IODBDMAMemoryCursor *
408: withSpecification(IOPhysicalLength maxSegmentSize,
409: IOPhysicalLength maxTransferSize,
410: IOPhysicalLength alignment = 1);
411:
412: /*! @function initWithSpecification
413: @abstract Primary initialiser for the IODBDMAMemoryCursor class.
414: @param maxSegmentSize Maximum allowable size for one segment. Defaults to 0.
415: @param maxTransferSize Maximum size of an entire transfer. Default to 0 indicating no maximum.
416: @param alignment Alligment restrictions on output physical addresses. Not currently implemented. Defaults to single byte alignment.
417: @result true if the inherited classes and this instance initialise
418: successfully.
419: */
420: virtual bool initWithSpecification(IOPhysicalLength maxSegmentSize,
421: IOPhysicalLength maxTransferSize,
422: IOPhysicalLength alignment = 1);
423:
424:
425: /*! @function getPhysicalSegments
426: @abstract Generate a DBDMA physical scatter/gather list given a memory descriptor.
427: @discussion Generates a list of DBDMA descriptors where the address and length fields are filled in appropriately. But the client is expected to fill in the rest of teh DBDMA descriptor as is appropriate for their particular hardware. Wraps $link IOMemoryCursor::genPhysicalSegments.
428: @param descriptor IOMemoryDescriptor that describes the data associated with an I/O request.
429: @param fromPosition Starting location of the I/O within a memory descriptor.
430: @param segments Pointer to an array of DBDMA descriptors for the output physical scatter/gather list. Be warned no room is left for a preamble in the output array. 'segments' should point to the first memory description slot in a DBDMA command.
431: @param maxSegments Maximum number of segments that can be written to the dbdma descriptor table.
432: @param maxTransferSize Maximum transfer size is limited to that many bytes, otherwise it defaults to the maximum transfer size specified when the memory cursor was initialized.
433: @param transferSize Pointer to a IOByteCount variable that can contain the total size of the transfer being described. Default to 0 indicating that no transfer size need be returned.
434: @result If the descriptor is exhausted of memory, a zero is returned, otherwise the number of segments that were filled in is returned.
435: */
436: virtual UInt32 getPhysicalSegments(IOMemoryDescriptor * descriptor,
437: IOByteCount fromPosition,
438: IODBDMADescriptor * segments,
439: UInt32 maxSegments,
440: UInt32 maxTransferSize = 0,
441: IOByteCount * transferSize = 0)
442: {
443: return genPhysicalSegments(descriptor, fromPosition, segments,
444: maxSegments, maxTransferSize, transferSize);
445: }
446: };
447:
448: #endif /* defined(__ppc__) */
449:
450: #endif /* !_IOMEMORYCURSOR_H */
451:
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