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1 | // ========== Copyright Header Begin ========================================== |
2 | // | |
3 | // OpenSPARC T2 Processor File: CTRapIDManager.vr | |
4 | // Copyright (C) 1995-2007 Sun Microsystems, Inc. All Rights Reserved | |
5 | // 4150 Network Circle, Santa Clara, California 95054, U.S.A. | |
6 | // | |
7 | // * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
8 | // | |
9 | // This program is free software; you can redistribute it and/or modify | |
10 | // it under the terms of the GNU General Public License as published by | |
11 | // the Free Software Foundation; version 2 of the License. | |
12 | // | |
13 | // This program is distributed in the hope that it will be useful, | |
14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | // GNU General Public License for more details. | |
17 | // | |
18 | // You should have received a copy of the GNU General Public License | |
19 | // along with this program; if not, write to the Free Software | |
20 | // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
21 | // | |
22 | // For the avoidance of doubt, and except that if any non-GPL license | |
23 | // choice is available it will apply instead, Sun elects to use only | |
24 | // the General Public License version 2 (GPLv2) at this time for any | |
25 | // software where a choice of GPL license versions is made | |
26 | // available with the language indicating that GPLv2 or any later version | |
27 | // may be used, or where a choice of which version of the GPL is applied is | |
28 | // otherwise unspecified. | |
29 | // | |
30 | // Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
31 | // CA 95054 USA or visit www.sun.com if you need additional information or | |
32 | // have any questions. | |
33 | // | |
34 | // ========== Copyright Header End ============================================ | |
35 | #include <vera_defines.vrh> | |
36 | #include "CTRapIDDefines.vri" | |
37 | ||
38 | // This class defines a manager that allocates tuples the form: | |
39 | // | |
40 | // <Device-ID><Packet-ID> | |
41 | // | |
42 | // where: | |
43 | // | |
44 | // Device-ID is a number that corresponds to one of N devices. | |
45 | // | |
46 | // Packet-ID is a number that corresponds to one of N | |
47 | // transactions from Device-ID. | |
48 | // | |
49 | // The combination of Device-ID and Packet-ID is guaranteed to | |
50 | // be unique in that the manager will not issue the same combination | |
51 | // until the previous instance has been deallocated. | |
52 | // | |
53 | // The assumption is that this class will be used to allocate raptor | |
54 | // request IDs, hence some of those assumptions are built into this class. | |
55 | // In particular, bit zero of the device ID is set to zero in all IDs | |
56 | // that are returned by the Allocate function. Also, bit zero of the | |
57 | // packet ID field is used to signify a read or write transaction. | |
58 | ||
59 | ||
60 | class CTRapIDManager { | |
61 | ||
62 | integer Policy = CT_RANDOM_ALLOC; | |
63 | ||
64 | //Packet-ID (PID) Pools. Separate pools allow two outstanding PIDs to | |
65 | //differ only in bit zero, which gets tacked on after a PID is selected. | |
66 | local bit [CT_NUMBER_OF_PKT_IDS-1:0] ReadPIDPool[CT_NUMBER_OF_DEVICES]; | |
67 | local bit [CT_NUMBER_OF_PKT_IDS-1:0] WritePIDPool[CT_NUMBER_OF_DEVICES]; | |
68 | ||
69 | local integer AllocSema; | |
70 | ||
71 | ////////////////////////////////////// Public Methods ///////////////////////////////////////////////////// | |
72 | ||
73 | task new (bit [CT_NUMBER_OF_PKT_IDS-1:0] PIDMask = CT_PKT_ID_MASK_DEFAULT) { | |
74 | integer Device; | |
75 | ||
76 | ||
77 | if (PIDMask === 0) | |
78 | error("CTRapIDManager(new)::At least one packet ID must be enabled\n"); | |
79 | else if ((^PIDMask) === 1'bx) | |
80 | error("CTRapIDManager(new)::X-values are not allowed in packet ID mask\n"); | |
81 | ||
82 | AllocSema = alloc(SEMAPHORE,0,1,1); | |
83 | ||
84 | if (AllocSema == 0) | |
85 | error("CTRapIDManager:: Out of semaphore space.\n\n"); | |
86 | ||
87 | ||
88 | //Fill the PID Pools | |
89 | for (Device=0; Device < CT_NUMBER_OF_DEVICES; ++Device) { | |
90 | ReadPIDPool[Device] = PIDMask; | |
91 | WritePIDPool[Device] = PIDMask; | |
92 | } | |
93 | ||
94 | } | |
95 | ||
96 | function bit [CT_RAP_ID_WIDTH-1:0] Allocate (bit RW, | |
97 | integer Timeout, | |
98 | bit [CT_NUMBER_OF_DEVICES-1:0] DeviceMask = CT_DEVICE_MASK_DEFAULT | |
99 | ) { | |
100 | bit [CT_INTERNAL_DEVICE_ID_WIDTH-1:0] Device; | |
101 | bit [CT_INTERNAL_PKT_ID_WIDTH-1:0] PID; | |
102 | ||
103 | semaphore_get(WAIT, AllocSema, 1); | |
104 | ||
105 | if (DeviceMask === 0) | |
106 | error("CTRapIDManager(Allocate)::At least one active device must be specified\n"); | |
107 | else if ((^DeviceMask) === 1'bx) | |
108 | error("CTRapIDManager(Allocate)::X-values are not allowed in device mask\n"); | |
109 | ||
110 | if (Timeout === 0) | |
111 | error("CTRapIDManager(Allocate)::At least one cycle timeout window needed to select ID\n"); | |
112 | ||
113 | Device = SelectDevice(RW, Policy, Timeout, DeviceMask) ; | |
114 | ||
115 | ||
116 | //This is a PID out of the read or write pool, depending on the value of RW. | |
117 | //The final value of PID comes after appending RW bit. | |
118 | PID = SelectPID(RW, Policy, Device); | |
119 | ||
120 | //Take ID out of the pool | |
121 | ||
122 | if (RW == CT_RAP_READ) | |
123 | ReadPIDPool[Device] &= ~(1'b1 << PID); | |
124 | else | |
125 | WritePIDPool[Device] &= ~(1'b1 << PID); | |
126 | ||
127 | //Bit zero of device ID always zero; Bit zero of packet ID specifies read or write | |
128 | Allocate = {Device, 1'b0, PID, RW}; | |
129 | ||
130 | semaphore_put(AllocSema, 1); | |
131 | } | |
132 | ||
133 | ||
134 | task Deallocate (bit [CT_RAP_ID_WIDTH-1:0] ID) { | |
135 | bit [CT_INTERNAL_DEVICE_ID_WIDTH-1:0] Device = ID[CT_DEVICE_ID_RANGE]; | |
136 | bit [CT_INTERNAL_PKT_ID_WIDTH-1:0] PID = ID[CT_PKT_ID_RANGE]; | |
137 | ||
138 | if ((^ID) === 1'bx) | |
139 | error("CTRapIDManager(Deallocate)::X-values are not allowed in ID\n"); | |
140 | ||
141 | if (PID[0] == CT_RAP_READ) | |
142 | ReadPIDPool[Device] |= (1'b1 << (PID >> 1)); | |
143 | else | |
144 | WritePIDPool[Device] |= (1'b1 << (PID >> 1)); | |
145 | } | |
146 | ||
147 | ||
148 | task SetPIDMask (bit [CT_NUMBER_OF_PKT_IDS-1:0] PIDMask) { | |
149 | integer Device; | |
150 | ||
151 | if (PIDMask === 0) | |
152 | error("CTRapIDManager(SetPIDMask)::At least one packet ID must be enabled\n"); | |
153 | else if ((^PIDMask) === 1'bx) | |
154 | error("CTRapIDManager(SetPIDMask)::X-values are not allowed in packet ID mask\n"); | |
155 | ||
156 | //Fill the PID Pools | |
157 | for (Device=0; Device < CT_NUMBER_OF_DEVICES; ++Device) { | |
158 | ReadPIDPool[Device] = PIDMask; | |
159 | WritePIDPool[Device] = PIDMask; | |
160 | } | |
161 | } | |
162 | ||
163 | ////////////////////////////////////// Private Methods ///////////////////////////////////////////////////// | |
164 | ||
165 | //It is assumed that Device has PIDs available before this function is called. | |
166 | //Otherwise, SelectRandomPID will pull an error. | |
167 | local function bit [CT_INTERNAL_PKT_ID_WIDTH-1:0] SelectPID(bit RW, | |
168 | integer Policy, | |
169 | bit [CT_INTERNAL_DEVICE_ID_WIDTH-1:0] Device) { | |
170 | bit [CT_NUMBER_OF_PKT_IDS-1:0] PIDVector = (RW == CT_RAP_READ)? ReadPIDPool[Device]:WritePIDPool[Device]; | |
171 | bit [CT_INTERNAL_PKT_ID_WIDTH-1:0] PIDPosition; | |
172 | ||
173 | ||
174 | case (Policy) | |
175 | { | |
176 | CT_RANDOM_ALLOC: | |
177 | { | |
178 | SelectPID = SelectRandomPID(PIDVector); | |
179 | } | |
180 | CT_SEQUENTIAL_ALLOC: | |
181 | { | |
182 | //The meaning of this is still unclear. Maybe random is the only thing that makes sense? | |
183 | ||
184 | } | |
185 | ||
186 | default: error("CTRapIDManager(Allocate)::Allocation policy unsupported!\n"); | |
187 | } | |
188 | } | |
189 | ||
190 | local function bit [CT_INTERNAL_DEVICE_ID_WIDTH-1:0] SelectDevice(bit RW, | |
191 | integer Policy, | |
192 | integer Timeout, | |
193 | bit [CT_NUMBER_OF_DEVICES-1:0] DeviceMask) { | |
194 | bit [CT_INTERNAL_DEVICE_ID_WIDTH-1:0] DevicePosition; | |
195 | bit Done = 0; | |
196 | ||
197 | case (Policy) | |
198 | { | |
199 | CT_RANDOM_ALLOC: | |
200 | { | |
201 | while (!Done && Timeout > 0) { | |
202 | ||
203 | DevicePosition = SelectRandomDevice(DeviceMask); | |
204 | ||
205 | if (PIDIsAvailable(DevicePosition, RW)) | |
206 | //No cycle time should expire if a PID is available for selected device | |
207 | Done = 1; | |
208 | else { | |
209 | //Try again | |
210 | --Timeout; | |
211 | @(posedge CLOCK); | |
212 | } | |
213 | } | |
214 | ||
215 | if (Timeout == 0) | |
216 | error("CTRapIDManager(Allocate)::Allocation Timeout \n"); | |
217 | ||
218 | SelectDevice = DevicePosition; | |
219 | } | |
220 | CT_SEQUENTIAL_ALLOC: | |
221 | { | |
222 | //The meaning of this is still unclear. Maybe random is the only thing that makes sense? | |
223 | ||
224 | } | |
225 | ||
226 | default: error("CTRapIDManager(Allocate)::Allocation policy unsupported!\n"); | |
227 | } | |
228 | } | |
229 | ||
230 | ||
231 | //Return true is at least one PID is available at DevicePosition | |
232 | local function bit PIDIsAvailable (bit [CT_INTERNAL_DEVICE_ID_WIDTH-1:0] DevicePosition, bit RW) { | |
233 | ||
234 | if (RW == CT_RAP_READ) | |
235 | PIDIsAvailable = (ReadPIDPool[DevicePosition])? 1'b1: 1'b0; | |
236 | else | |
237 | PIDIsAvailable = (WritePIDPool[DevicePosition])? 1'b1: 1'b0; | |
238 | } | |
239 | ||
240 | //---------------------------------------------------------------------------------------------------------- | |
241 | // function: SelectRandomDevice | |
242 | // Return any number with its corresponding bit set in the argument SetVector | |
243 | //---------------------------------------------------------------------------------------------------------- | |
244 | local function bit[CT_INTERNAL_DEVICE_ID_WIDTH-1:0] SelectRandomDevice (bit [CT_NUMBER_OF_DEVICES-1:0] SetVector) { | |
245 | integer i, j; | |
246 | ||
247 | j = 0; | |
248 | for (i = 0; i < CT_NUMBER_OF_DEVICES; i++) j = j + ((SetVector >> i) & 1'b1); | |
249 | if (j == 0) | |
250 | error ("SelectRandomDevice: set empty\n"); | |
251 | j = random() % j; | |
252 | ||
253 | for (i = 0; i < CT_NUMBER_OF_DEVICES; i++) | |
254 | if (((SetVector >> i) & 1'b1) == 1'b1) | |
255 | { | |
256 | if (j == 0) SelectRandomDevice = i; | |
257 | j = j - 1; | |
258 | } | |
259 | } | |
260 | ||
261 | //---------------------------------------------------------------------------------------------------------- | |
262 | // function: SelectRandomPID | |
263 | // Return any number with its corresponding bit set in the argument SetVector | |
264 | //---------------------------------------------------------------------------------------------------------- | |
265 | local function bit[CT_INTERNAL_PKT_ID_WIDTH-1:0] SelectRandomPID (bit [CT_NUMBER_OF_PKT_IDS-1:0] SetVector) { | |
266 | integer i, j; | |
267 | ||
268 | j = 0; | |
269 | for (i = 0; i < CT_NUMBER_OF_PKT_IDS; i++) j = j + ((SetVector >> i) & 1'b1); | |
270 | if (j == 0) | |
271 | error ("SelectRandomTid: set empty\n"); | |
272 | j = random() % j; | |
273 | ||
274 | for (i = 0; i < CT_NUMBER_OF_PKT_IDS; i++) | |
275 | if (((SetVector >> i) & 1'b1) == 1'b1) | |
276 | { | |
277 | if (j == 0) SelectRandomPID = i; | |
278 | j = j - 1; | |
279 | } | |
280 | } | |
281 | ||
282 | } | |
283 | ||
284 | ||
285 | ||
286 |