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Tomas Hlavacekf07563a2012-08-08 01:42:26 +00001The U-Boot Driver Model Project
2===============================
3Watchdog device subsystem analysis
4==================================
5
6Tomas Hlavacek <tmshlvck@gmail.com>
72012-03-09
8
9I) Overview
10-----------
11
12U-Boot currently implements an API for HW watchdog devices as explicit drivers
13in drivers/watchdog directory. There are also drivers for both hardware and
14software watchdog on particular CPUs implemented in arch/*/cpu/*/cpu.c. There
15are macros in include/watchdog.h that selects between SW and HW watchdog and
16assembly SW implementation.
17
18The current common interface comprises of one set out of these two possible
19variants:
20
21 1)
22 void watchdog_reset(void);
23 int watchdog_disable(void);
24 int watchdog_init(void);
25
26 2)
27 void hw_watchdog_reset(void);
28 void hw_watchdog_init(void);
29
30The watchdog implementations are also spread through board/*/*.c that in
31some cases. The API and semantics is in most cases same as the above
32mentioned common functions.
33
34
35II) Approach
36------------
37
38 1) New API
39 ----------
40
41 In the UDM each watchdog driver would register itself by a function
42
43 int watchdog_device_register(struct instance *i,
44 const struct watchdog_device_ops *o);
45
46 The structure being defined as follows:
47
48 struct watchdog_device_ops {
49 int (*disable)(struct instance *i);
50 void (*reset)(struct instance *i);
51 };
52
53 The watchdog_init() function will be dissolved into probe() function.
54
55 2) Conversion thougths
56 ----------------------
57
58 Conversion of watchdog implementations to a new API could be divided
59 to three subsections: a) HW implementations, which are mostly compliant
60 to the above mentioned API; b) SW implementations, which are compliant
61 to the above mentioned API and c) SW implementations that are not compliant
62 to the API and has to be rectified or partially rewritten.
63
64III) Analysis of in-tree drivers
65--------------------------------
66
67 1) drivers/watchdog/at91sam9_wdt.c
68 ----------------------------------
69 The driver is standard HW watchdog. Simple conversion is possible.
70
71
72 2) drivers/watchdog/ftwdt010_wdt.c
73 ----------------------------------
74 The driver is ad-hoc HW watchdog. Conversion has to take into account
75 driver parts spread in include/faraday/*. Restructuring the driver and
76 code cleanup has to be considered.
77
78
79 3) arch/arm/cpu/arm1136/mx31/timer.c
80 ------------------------------------
81 The driver is semi-standard ad-hoc HW watchdog. Conversion has to take
82 into account driver parts spread in the timer.c file.
83
84
85 4) arch/arm/cpu/arm926ejs/davinci/timer.c
86 -----------------------------------------
87 The driver is ad-hoc semi-standard HW watchdog. Conversion has to take
88 into account driver parts spread in the timer.c file.
89
90
91 5) arch/arm/cpu/armv7/omap-common/hwinit-common.c
92 -------------------------------------------------
93 The driver is non-standard ad-hoc HW watchdog. Conversion is possible
94 but functions has to be renamed and constants moved to another places.
95
96
97 6) arch/arm/cpu/armv7/omap3/board.c
98 -----------------------------------
99 The driver is non-standard ad-hoc HW watchdog. Conversion is possible
100 but functions has to be renamed and constants moved to another places.
101
102
103 7) arch/blackfin/cpu/watchdog.c
104 -------------------------------
105 The driver is standard HW watchdog. Simple conversion is possible.
106
107
108 8) arch/m68k/cpu/mcf523x/cpu.c
109 ------------------------------
110 The driver is standard HW watchdog. Simple conversion is possible.
111
112
113 9) arch/m68k/cpu/mcf52x2/cpu.c
114 ------------------------------
115 The driver is standard HW watchdog. Simple conversion is possible.
116
117
118 10) arch/m68k/cpu/mcf532x/cpu.c
119 -------------------------------
120 The driver is standard HW watchdog. Simple conversion is possible.
121
122
123 11) arch/m68k/cpu/mcf547x_8x/cpu.c
124 ----------------------------------
125 The driver is standard HW watchdog (there is slight naming convention
126 violation that has to be rectified). Simple conversion is possible.
127
128
129 12) arch/powerpc/cpu/74xx_7xx/cpu.c
130 -----------------------------------
131 The driver is standard HW watchdog. Simple conversion is possible.
132
133
134 13) arch/powerpc/cpu/mpc512x/cpu.c
135 ----------------------------------
136 The driver is standard HW watchdog. Simple conversion is possible.
137
138
139 14) arch/powerpc/cpu/mpc5xx/cpu.c
140 ---------------------------------
141 The driver is standard HW watchdog. Simple conversion is possible.
142
143
144 15) arch/powerpc/cpu/mpc5xxx/cpu.c
145 ----------------------------------
146 The driver is standard HW watchdog. Simple conversion is possible.
147
148
149 16) arch/powerpc/cpu/mpc8260/cpu.c
150 ----------------------------------
151 The driver is standard HW watchdog. Simple conversion is possible.
152
153
154 17) arch/powerpc/cpu/mpc83xx/cpu.c
155 ----------------------------------
156 The driver is standard HW watchdog. Simple conversion is possible.
157
158
159 18) arch/powerpc/cpu/mpc85xx/cpu.c
160 ----------------------------------
161 The driver is standard HW watchdog. Simple conversion is possible.
162
163
164 19) arch/powerpc/cpu/mpc86xx/cpu.c
165 ----------------------------------
166 The driver is standard HW watchdog. Simple conversion is possible.
167
168
169 20) arch/powerpc/cpu/mpc8xx/cpu.c
170
171 The driver is standard HW watchdog. Simple conversion is possible.
172
173
174 21) arch/powerpc/cpu/ppc4xx/cpu.c
175 ---------------------------------
176 The driver is standard HW watchdog. Simple conversion is possible.
177
178
179 22) arch/sh/cpu/sh2/watchdog.c
180 ------------------------------
181 The driver is standard HW watchdog. Simple conversion is possible.
182
183
184 23) arch/sh/cpu/sh3/watchdog.c
185 ------------------------------
186 The driver is standard HW watchdog. Simple conversion is possible.
187
188
189 24) arch/sh/cpu/sh4/watchdog.c
190 ------------------------------
191 The driver is standard HW watchdog. Simple conversion is possible.
192
193
194 25) board/amcc/luan/luan.c
195 --------------------------
196 The driver is standard HW watchdog. Simple conversion is possible.
197
198
199 26) board/amcc/yosemite/yosemite.c
200 ----------------------------------
201 The driver is standard HW watchdog. Simple conversion is possible.
202
203
204 27) board/apollon/apollon.c
205 ---------------------------
206 The driver is standard HW watchdog however the watchdog_init()
207 function is called in early initialization. Simple conversion is possible.
208
209
210 28) board/bmw/m48t59y.c
211 -----------------------
212 Special watchdog driver. Dead code. To be removed.
213
214
215 29) board/davedenx/qong/qong.c
216 ------------------------------
217 The driver is standard HW watchdog. Simple conversion is possible.
218
219
220 30) board/dvlhost/watchdog.c
221 ----------------------------
222 The driver is standard HW watchdog. Simple conversion is possible.
223
224
225 31) board/eNET/eNET.c
226 ---------------------
227 The driver is standard HW watchdog. Simple conversion is possible.
228
229
230 32) board/eltec/elppc/elppc.c
231 -----------------------------
232 The driver is standard HW watchdog. Simple conversion is possible.
233
234
235 33) board/enbw/enbw_cmc/enbw_cmc.c
236 ----------------------------------
237 Only function proxy call. Code cleanup needed.
238
239
240 34) board/freescale/mx31pdk/mx31pdk.c
241 -------------------------------------
242 Only function proxy call. Code cleanup needed.
243
244
245 35) board/gth2/gth2.c
246 ---------------------
247 The driver is standard HW watchdog. Simple conversion is possible.
248
249
250 36) board/lwmon5/lwmon5.c
251 -------------------------
252 The driver is standard HW watchdog. Simple conversion is possible.
253
254
255 37) board/manroland/mucmc52/mucmc52.c
256 -------------------------------------
257 The driver is standard HW watchdog. Simple conversion is possible.
258
259
260 38) board/manroland/uc101/uc101.c
261 ---------------------------------
262 The driver is standard HW watchdog. Simple conversion is possible.
263
264
265 39) board/mousse/m48t59y.c
266 --------------------------
267 Special watchdog driver. Dead code. To be removed.
268
269
270 40) board/mvblue/mvblue.c
271 -------------------------
272 The driver is standard HW watchdog. Simple conversion is possible.
273
274
275 41) board/netphone/netphone.c
276 -----------------------------
277 The driver is standard HW watchdog. Simple conversion is possible.
278
279
280 42) board/netta/netta.c
281 -----------------------
282 The driver is standard HW watchdog. Simple conversion is possible.
283
284
285 43) board/netta2/netta2.c
286 -------------------------
287 The driver is standard HW watchdog. Simple conversion is possible.
288
289
290 44) board/omicron/calimain/calimain.c
291 -------------------------------------
292 Only function proxy call. Code cleanup needed.
293
294
295 45) board/pcippc2/pcippc2.c
296 ---------------------------
297 The driver is standard HW watchdog. Simple conversion is possible.
298
299
300 46) board/pcs440ep/pcs440ep.c
301 -----------------------------
302 The driver is standard HW watchdog. Simple conversion is possible.
303
304
305 47) board/stx/stxxtc/stxxtc.c
306 -----------------------------
307 The driver is standard HW watchdog. Simple conversion is possible.
308
309
310 48) board/ti/omap2420h4/omap2420h4.c
311 ------------------------------------
312 The driver is standard HW watchdog. Simple conversion is possible.
313
314
315 49) board/ttcontrol/vision2/vision2.c
316 -------------------------------------
317 The driver is standard HW watchdog but namespace is polluted by
318 non-standard macros. Simple conversion is possible, code cleanup
319 needed.
320
321
322 50) board/v38b/v38b.c
323 ---------------------
324 The driver is standard HW watchdog. Simple conversion is possible.
325
326
327 51) board/ve8313/ve8313.c
328 -------------------------
329 The driver is standard HW watchdog. Simple conversion is possible.
330
331
332 52) board/w7o/watchdog.c
333 ------------------------
334 The driver is standard HW watchdog. Simple conversion is possible.