summaryrefslogtreecommitdiffstats
path: root/drivers/gpu/drm/amd/amdgpu/vid.h
blob: 7a3863a45f0af64e07a2b4657b6011a67133c4c2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
/*
 * Copyright 2014 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 */
#ifndef VI_H
#define VI_H

#define SDMA0_REGISTER_OFFSET                             0x0 /* not a register */
#define SDMA1_REGISTER_OFFSET                             0x200 /* not a register */
#define SDMA_MAX_INSTANCE 2

/* crtc instance offsets */
#define CRTC0_REGISTER_OFFSET                 (0x1b9c - 0x1b9c)
#define CRTC1_REGISTER_OFFSET                 (0x1d9c - 0x1b9c)
#define CRTC2_REGISTER_OFFSET                 (0x1f9c - 0x1b9c)
#define CRTC3_REGISTER_OFFSET                 (0x419c - 0x1b9c)
#define CRTC4_REGISTER_OFFSET                 (0x439c - 0x1b9c)
#define CRTC5_REGISTER_OFFSET                 (0x459c - 0x1b9c)
#define CRTC6_REGISTER_OFFSET                 (0x479c - 0x1b9c)

/* dig instance offsets */
#define DIG0_REGISTER_OFFSET                 (0x4a00 - 0x4a00)
#define DIG1_REGISTER_OFFSET                 (0x4b00 - 0x4a00)
#define DIG2_REGISTER_OFFSET                 (0x4c00 - 0x4a00)
#define DIG3_REGISTER_OFFSET                 (0x4d00 - 0x4a00)
#define DIG4_REGISTER_OFFSET                 (0x4e00 - 0x4a00)
#define DIG5_REGISTER_OFFSET                 (0x4f00 - 0x4a00)
#define DIG6_REGISTER_OFFSET                 (0x5400 - 0x4a00)
#define DIG7_REGISTER_OFFSET                 (0x5600 - 0x4a00)
#define DIG8_REGISTER_OFFSET                 (0x5700 - 0x4a00)

/* audio endpt instance offsets */
#define AUD0_REGISTER_OFFSET                 (0x17a8 - 0x17a8)
#define AUD1_REGISTER_OFFSET                 (0x17ac - 0x17a8)
#define AUD2_REGISTER_OFFSET                 (0x17b0 - 0x17a8)
#define AUD3_REGISTER_OFFSET                 (0x17b4 - 0x17a8)
#define AUD4_REGISTER_OFFSET                 (0x17b8 - 0x17a8)
#define AUD5_REGISTER_OFFSET                 (0x17bc - 0x17a8)
#define AUD6_REGISTER_OFFSET                 (0x17c0 - 0x17a8)
#define AUD7_REGISTER_OFFSET                 (0x17c4 - 0x17a8)

/* hpd instance offsets */
#define HPD0_REGISTER_OFFSET                 (0x1898 - 0x1898)
#define HPD1_REGISTER_OFFSET                 (0x18a0 - 0x1898)
#define HPD2_REGISTER_OFFSET                 (0x18a8 - 0x1898)
#define HPD3_REGISTER_OFFSET                 (0x18b0 - 0x1898)
#define HPD4_REGISTER_OFFSET                 (0x18b8 - 0x1898)
#define HPD5_REGISTER_OFFSET                 (0x18c0 - 0x1898)

#define AMDGPU_NUM_OF_VMIDS			8

#define		PIPEID(x)					((x) << 0)
#define		MEID(x)						((x) << 2)
#define		VMID(x)						((x) << 4)
#define		QUEUEID(x)					((x) << 8)

#define MC_SEQ_MISC0__MT__MASK	0xf0000000
#define MC_SEQ_MISC0__MT__GDDR1  0x10000000
#define MC_SEQ_MISC0__MT__DDR2   0x20000000
#define MC_SEQ_MISC0__MT__GDDR3  0x30000000
#define MC_SEQ_MISC0__MT__GDDR4  0x40000000
#define MC_SEQ_MISC0__MT__GDDR5  0x50000000
#define MC_SEQ_MISC0__MT__HBM    0x60000000
#define MC_SEQ_MISC0__MT__DDR3   0xB0000000

/*
 * PM4
 */
#define	PACKET_TYPE0	0
#define	PACKET_TYPE1	1
#define	PACKET_TYPE2	2
#define	PACKET_TYPE3	3

#define CP_PACKET_GET_TYPE(h) (((h) >> 30) & 3)
#define CP_PACKET_GET_COUNT(h) (((h) >> 16) & 0x3FFF)
#define CP_PACKET0_GET_REG(h) ((h) & 0xFFFF)
#define CP_PACKET3_GET_OPCODE(h) (((h) >> 8) & 0xFF)
#define PACKET0(reg, n)	((PACKET_TYPE0 << 30) |				\
			 ((reg) & 0xFFFF) |			\
			 ((n) & 0x3FFF) << 16)
#define CP_PACKET2			0x80000000
#define		PACKET2_PAD_SHIFT		0
#define		PACKET2_PAD_MASK		(0x3fffffff << 0)

#define PACKET2(v)	(CP_PACKET2 | REG_SET(PACKET2_PAD, (v)))

#define PACKET3(op, n)	((PACKET_TYPE3 << 30) |				\
			 (((op) & 0xFF) << 8) |				\
			 ((n) & 0x3FFF) << 16)

#define PACKET3_COMPUTE(op, n) (PACKET3(op, n) | 1 << 1)

/* Packet 3 types */
#define	PACKET3_NOP					0x10
#define	PACKET3_SET_BASE				0x11
#define		PACKET3_BASE_INDEX(x)                  ((x) << 0)
#define			CE_PARTITION_BASE		3
#define	PACKET3_CLEAR_STATE				0x12
#define	PACKET3_INDEX_BUFFER_SIZE			0x13
#define	PACKET3_DISPATCH_DIRECT				0x15
#define	PACKET3_DISPATCH_INDIRECT			0x16
#define	PACKET3_ATOMIC_GDS				0x1D
#define	PACKET3_ATOMIC_MEM				0x1E
#define	PACKET3_OCCLUSION_QUERY				0x1F
#define	PACKET3_SET_PREDICATION				0x20
#define	PACKET3_REG_RMW					0x21
#define	PACKET3_COND_EXEC				0x22
#define	PACKET3_PRED_EXEC				0x23
#define	PACKET3_DRAW_INDIRECT				0x24
#define	PACKET3_DRAW_INDEX_INDIRECT			0x25
#define	PACKET3_INDEX_BASE				0x26
#define	PACKET3_DRAW_INDEX_2				0x27
#define	PACKET3_CONTEXT_CONTROL				0x28
#define	PACKET3_INDEX_TYPE				0x2A
#define	PACKET3_DRAW_INDIRECT_MULTI			0x2C
#define	PACKET3_DRAW_INDEX_AUTO				0x2D
#define	PACKET3_NUM_INSTANCES				0x2F
#define	PACKET3_DRAW_INDEX_MULTI_AUTO			0x30
#define	PACKET3_INDIRECT_BUFFER_CONST			0x33
#define	PACKET3_STRMOUT_BUFFER_UPDATE			0x34
#define	PACKET3_DRAW_INDEX_OFFSET_2			0x35
#define	PACKET3_DRAW_PREAMBLE				0x36
#define	PACKET3_WRITE_DATA				0x37
#define		WRITE_DATA_DST_SEL(x)                   ((x) << 8)
		/* 0 - register
		 * 1 - memory (sync - via GRBM)
		 * 2 - gl2
		 * 3 - gds
		 * 4 - reserved
		 * 5 - memory (async - direct)
		 */
#define		WR_ONE_ADDR                             (1 << 16)
#define		WR_CONFIRM                              (1 << 20)
#define		WRITE_DATA_CACHE_POLICY(x)              ((x) << 25)
		/* 0 - LRU
		 * 1 - Stream
		 */
#define		WRITE_DATA_ENGINE_SEL(x)                ((x) << 30)
		/* 0 - me
		 * 1 - pfp
		 * 2 - ce
		 */
#define	PACKET3_DRAW_INDEX_INDIRECT_MULTI		0x38
#define	PACKET3_MEM_SEMAPHORE				0x39
#              define PACKET3_SEM_USE_MAILBOX       (0x1 << 16)
#              define PACKET3_SEM_SEL_SIGNAL_TYPE   (0x1 << 20) /* 0 = increment, 1 = write 1 */
#              define PACKET3_SEM_CLIENT_CODE	    ((x) << 24) /* 0 = CP, 1 = CB, 2 = DB */
#              define PACKET3_SEM_SEL_SIGNAL	    (0x6 << 29)
#              define PACKET3_SEM_SEL_WAIT	    (0x7 << 29)
#define	PACKET3_WAIT_REG_MEM				0x3C
#define		WAIT_REG_MEM_FUNCTION(x)                ((x) << 0)
		/* 0 - always
		 * 1 - <
		 * 2 - <=
		 * 3 - ==
		 * 4 - !=
		 * 5 - >=
		 * 6 - >
		 */
#define		WAIT_REG_MEM_MEM_SPACE(x)               ((x) << 4)
		/* 0 - reg
		 * 1 - mem
		 */
#define		WAIT_REG_MEM_OPERATION(x)               ((x) << 6)
		/* 0 - wait_reg_mem
		 * 1 - wr_wait_wr_reg
		 */
#define		WAIT_REG_MEM_ENGINE(x)                  ((x) << 8)
		/* 0 - me
		 * 1 - pfp
		 */
#define	PACKET3_INDIRECT_BUFFER				0x3F
#define		INDIRECT_BUFFER_TCL2_VOLATILE           (1 << 22)
#define		INDIRECT_BUFFER_VALID                   (1 << 23)
#define		INDIRECT_BUFFER_CACHE_POLICY(x)         ((x) << 28)
		/* 0 - LRU
		 * 1 - Stream
		 * 2 - Bypass
		 */
#define	PACKET3_COPY_DATA				0x40
#define	PACKET3_PFP_SYNC_ME				0x42
#define	PACKET3_SURFACE_SYNC				0x43
#              define PACKET3_DEST_BASE_0_ENA      (1 << 0)
#              define PACKET3_DEST_BASE_1_ENA      (1 << 1)
#              define PACKET3_CB0_DEST_BASE_ENA    (1 << 6)
#              define PACKET3_CB1_DEST_BASE_ENA    (1 << 7)
#              define PACKET3_CB2_DEST_BASE_ENA    (1 << 8)
#              define PACKET3_CB3_DEST_BASE_ENA    (1 << 9)
#              define PACKET3_CB4_DEST_BASE_ENA    (1 << 10)
#              define PACKET3_CB5_DEST_BASE_ENA    (1 << 11)
#              define PACKET3_CB6_DEST_BASE_ENA    (1 << 12)
#              define PACKET3_CB7_DEST_BASE_ENA    (1 << 13)
#              define PACKET3_DB_DEST_BASE_ENA     (1 << 14)
#              define PACKET3_TCL1_VOL_ACTION_ENA  (1 << 15)
#              define PACKET3_TC_VOL_ACTION_ENA    (1 << 16) /* L2 */
#              define PACKET3_TC_WB_ACTION_ENA     (1 << 18) /* L2 */
#              define PACKET3_DEST_BASE_2_ENA      (1 << 19)
#              define PACKET3_DEST_BASE_3_ENA      (1 << 21)
#              define PACKET3_TCL1_ACTION_ENA      (1 << 22)
#              define PACKET3_TC_ACTION_ENA        (1 << 23) /* L2 */
#              define PACKET3_CB_ACTION_ENA        (1 << 25)
#              define PACKET3_DB_ACTION_ENA        (1 << 26)
#              define PACKET3_SH_KCACHE_ACTION_ENA (1 << 27)
#              define PACKET3_SH_KCACHE_VOL_ACTION_ENA (1 << 28)
#              define PACKET3_SH_ICACHE_ACTION_ENA (1 << 29)
#define	PACKET3_COND_WRITE				0x45
#define	PACKET3_EVENT_WRITE				0x46
#define		EVENT_TYPE(x)                           ((x) << 0)
#define		EVENT_INDEX(x)                          ((x) << 8)
		/* 0 - any non-TS event
		 * 1 - ZPASS_DONE, PIXEL_PIPE_STAT_*
		 * 2 - SAMPLE_PIPELINESTAT
		 * 3 - SAMPLE_STREAMOUTSTAT*
		 * 4 - *S_PARTIAL_FLUSH
		 * 5 - EOP events
		 * 6 - EOS events
		 */
#define	PACKET3_EVENT_WRITE_EOP				0x47
#define		EOP_TCL1_VOL_ACTION_EN                  (1 << 12)
#define		EOP_TC_VOL_ACTION_EN                    (1 << 13) /* L2 */
#define		EOP_TC_WB_ACTION_EN                     (1 << 15) /* L2 */
#define		EOP_TCL1_ACTION_EN                      (1 << 16)
#define		EOP_TC_ACTION_EN                        (1 << 17) /* L2 */
#define		EOP_TCL2_VOLATILE                       (1 << 24)
#define		EOP_CACHE_POLICY(x)                     ((x) << 25)
		/* 0 - LRU
		 * 1 - Stream
		 * 2 - Bypass
		 */
#define		DATA_SEL(x)                             ((x) << 29)
		/* 0 - discard
		 * 1 - send low 32bit data
		 * 2 - send 64bit data
		 * 3 - send 64bit GPU counter value
		 * 4 - send 64bit sys counter value
		 */
#define		INT_SEL(x)                              ((x) << 24)
		/* 0 - none
		 * 1 - interrupt only (DATA_SEL = 0)
		 * 2 - interrupt when data write is confirmed
		 */
#define		DST_SEL(x)                              ((x) << 16)
		/* 0 - MC
		 * 1 - TC/L2
		 */
#define	PACKET3_EVENT_WRITE_EOS				0x48
#define	PACKET3_RELEASE_MEM				0x49
#define	PACKET3_PREAMBLE_CNTL				0x4A
#              define PACKET3_PREAMBLE_BEGIN_CLEAR_STATE     (2 << 28)
#              define PACKET3_PREAMBLE_END_CLEAR_STATE       (3 << 28)
#define	PACKET3_DMA_DATA				0x50
/* 1. header
 * 2. CONTROL
 * 3. SRC_ADDR_LO or DATA [31:0]
 * 4. SRC_ADDR_HI [31:0]
 * 5. DST_ADDR_LO [31:0]
 * 6. DST_ADDR_HI [7:0]
 * 7. COMMAND [30:21] | BYTE_COUNT [20:0]
 */
/* CONTROL */
#              define PACKET3_DMA_DATA_ENGINE(x)     ((x) << 0)
		/* 0 - ME
		 * 1 - PFP
		 */
#              define PACKET3_DMA_DATA_SRC_CACHE_POLICY(x) ((x) << 13)
		/* 0 - LRU
		 * 1 - Stream
		 * 2 - Bypass
		 */
#              define PACKET3_DMA_DATA_SRC_VOLATILE (1 << 15)
#              define PACKET3_DMA_DATA_DST_SEL(x)  ((x) << 20)
		/* 0 - DST_ADDR using DAS
		 * 1 - GDS
		 * 3 - DST_ADDR using L2
		 */
#              define PACKET3_DMA_DATA_DST_CACHE_POLICY(x) ((x) << 25)
		/* 0 - LRU
		 * 1 - Stream
		 * 2 - Bypass
		 */
#              define PACKET3_DMA_DATA_DST_VOLATILE (1 << 27)
#              define PACKET3_DMA_DATA_SRC_SEL(x)  ((x) << 29)
		/* 0 - SRC_ADDR using SAS
		 * 1 - GDS
		 * 2 - DATA
		 * 3 - SRC_ADDR using L2
		 */
#              define PACKET3_DMA_DATA_CP_SYNC     (1 << 31)
/* COMMAND */
#              define PACKET3_DMA_DATA_DIS_WC      (1 << 21)
#              define PACKET3_DMA_DATA_CMD_SRC_SWAP(x) ((x) << 22)
		/* 0 - none
		 * 1 - 8 in 16
		 * 2 - 8 in 32
		 * 3 - 8 in 64
		 */
#              define PACKET3_DMA_DATA_CMD_DST_SWAP(x) ((x) << 24)
		/* 0 - none
		 * 1 - 8 in 16
		 * 2 - 8 in 32
		 * 3 - 8 in 64
		 */
#              define PACKET3_DMA_DATA_CMD_SAS     (1 << 26)
		/* 0 - memory
		 * 1 - register
		 */
#              define PACKET3_DMA_DATA_CMD_DAS     (1 << 27)
		/* 0 - memory
		 * 1 - register
		 */
#              define PACKET3_DMA_DATA_CMD_SAIC    (1 << 28)
#              define PACKET3_DMA_DATA_CMD_DAIC    (1 << 29)
#              define PACKET3_DMA_DATA_CMD_RAW_WAIT  (1 << 30)
#define	PACKET3_AQUIRE_MEM				0x58
#define	PACKET3_REWIND					0x59
#define	PACKET3_LOAD_UCONFIG_REG			0x5E
#define	PACKET3_LOAD_SH_REG				0x5F
#define	PACKET3_LOAD_CONFIG_REG				0x60
#define	PACKET3_LOAD_CONTEXT_REG			0x61
#define	PACKET3_SET_CONFIG_REG				0x68
#define		PACKET3_SET_CONFIG_REG_START			0x00002000
#define		PACKET3_SET_CONFIG_REG_END			0x00002c00
#define	PACKET3_SET_CONTEXT_REG				0x69
#define		PACKET3_SET_CONTEXT_REG_START			0x0000a000
#define		PACKET3_SET_CONTEXT_REG_END			0x0000a400
#define	PACKET3_SET_CONTEXT_REG_INDIRECT		0x73
#define	PACKET3_SET_SH_REG				0x76
#define		PACKET3_SET_SH_REG_START			0x00002c00
#define		PACKET3_SET_SH_REG_END				0x00003000
#define	PACKET3_SET_SH_REG_OFFSET			0x77
#define	PACKET3_SET_QUEUE_REG				0x78
#define	PACKET3_SET_UCONFIG_REG				0x79
#define		PACKET3_SET_UCONFIG_REG_START			0x0000c000
#define		PACKET3_SET_UCONFIG_REG_END			0x0000c400
#define	PACKET3_SCRATCH_RAM_WRITE			0x7D
#define	PACKET3_SCRATCH_RAM_READ			0x7E
#define	PACKET3_LOAD_CONST_RAM				0x80
#define	PACKET3_WRITE_CONST_RAM				0x81
#define	PACKET3_DUMP_CONST_RAM				0x83
#define	PACKET3_INCREMENT_CE_COUNTER			0x84
#define	PACKET3_INCREMENT_DE_COUNTER			0x85
#define	PACKET3_WAIT_ON_CE_COUNTER			0x86
#define	PACKET3_WAIT_ON_DE_COUNTER_DIFF			0x88
#define	PACKET3_SWITCH_BUFFER				0x8B
#define	PACKET3_SET_RESOURCES				0xA0
#define	PACKET3_MAP_QUEUES				0xA2

#define VCE_CMD_NO_OP		0x00000000
#define VCE_CMD_END		0x00000001
#define VCE_CMD_IB		0x00000002
#define VCE_CMD_FENCE		0x00000003
#define VCE_CMD_TRAP		0x00000004
#define VCE_CMD_IB_AUTO	0x00000005
#define VCE_CMD_SEMAPHORE	0x00000006

#define VCE_CMD_IB_VM           0x00000102
#define VCE_CMD_WAIT_GE         0x00000106
#define VCE_CMD_UPDATE_PTB      0x00000107
#define VCE_CMD_FLUSH_TLB       0x00000108

/* mmPA_SC_RASTER_CONFIG mask */
#define RB_MAP_PKR0(x)				((x) << 0)
#define RB_MAP_PKR0_MASK			(0x3 << 0)
#define RB_MAP_PKR1(x)				((x) << 2)
#define RB_MAP_PKR1_MASK			(0x3 << 2)
#define RB_XSEL2(x)				((x) << 4)
#define RB_XSEL2_MASK				(0x3 << 4)
#define RB_XSEL					(1 << 6)
#define RB_YSEL					(1 << 7)
#define PKR_MAP(x)				((x) << 8)
#define PKR_MAP_MASK				(0x3 << 8)
#define PKR_XSEL(x)				((x) << 10)
#define PKR_XSEL_MASK				(0x3 << 10)
#define PKR_YSEL(x)				((x) << 12)
#define PKR_YSEL_MASK				(0x3 << 12)
#define SC_MAP(x)				((x) << 16)
#define SC_MAP_MASK				(0x3 << 16)
#define SC_XSEL(x)				((x) << 18)
#define SC_XSEL_MASK				(0x3 << 18)
#define SC_YSEL(x)				((x) << 20)
#define SC_YSEL_MASK				(0x3 << 20)
#define SE_MAP(x)				((x) << 24)
#define SE_MAP_MASK				(0x3 << 24)
#define SE_XSEL(x)				((x) << 26)
#define SE_XSEL_MASK				(0x3 << 26)
#define SE_YSEL(x)				((x) << 28)
#define SE_YSEL_MASK				(0x3 << 28)

/* mmPA_SC_RASTER_CONFIG_1 mask */
#define SE_PAIR_MAP(x)				((x) << 0)
#define SE_PAIR_MAP_MASK			(0x3 << 0)
#define SE_PAIR_XSEL(x)				((x) << 2)
#define SE_PAIR_XSEL_MASK			(0x3 << 2)
#define SE_PAIR_YSEL(x)				((x) << 4)
#define SE_PAIR_YSEL_MASK			(0x3 << 4)

#endif