xref: /openbmc/linux/arch/powerpc/include/asm/smu.h (revision 12eb4683)
1 #ifndef _SMU_H
2 #define _SMU_H
3 
4 /*
5  * Definitions for talking to the SMU chip in newer G5 PowerMacs
6  */
7 #ifdef __KERNEL__
8 #include <linux/list.h>
9 #endif
10 #include <linux/types.h>
11 
12 /*
13  * Known SMU commands
14  *
15  * Most of what is below comes from looking at the Open Firmware driver,
16  * though this is still incomplete and could use better documentation here
17  * or there...
18  */
19 
20 
21 /*
22  * Partition info commands
23  *
24  * These commands are used to retrieve the sdb-partition-XX datas from
25  * the SMU. The length is always 2. First byte is the subcommand code
26  * and second byte is the partition ID.
27  *
28  * The reply is 6 bytes:
29  *
30  *  - 0..1 : partition address
31  *  - 2    : a byte containing the partition ID
32  *  - 3    : length (maybe other bits are rest of header ?)
33  *
34  * The data must then be obtained with calls to another command:
35  * SMU_CMD_MISC_ee_GET_DATABLOCK_REC (described below).
36  */
37 #define SMU_CMD_PARTITION_COMMAND		0x3e
38 #define   SMU_CMD_PARTITION_LATEST		0x01
39 #define   SMU_CMD_PARTITION_BASE		0x02
40 #define   SMU_CMD_PARTITION_UPDATE		0x03
41 
42 
43 /*
44  * Fan control
45  *
46  * This is a "mux" for fan control commands. The command seem to
47  * act differently based on the number of arguments. With 1 byte
48  * of argument, this seem to be queries for fans status, setpoint,
49  * etc..., while with 0xe arguments, we will set the fans speeds.
50  *
51  * Queries (1 byte arg):
52  * ---------------------
53  *
54  * arg=0x01: read RPM fans status
55  * arg=0x02: read RPM fans setpoint
56  * arg=0x11: read PWM fans status
57  * arg=0x12: read PWM fans setpoint
58  *
59  * the "status" queries return the current speed while the "setpoint" ones
60  * return the programmed/target speed. It _seems_ that the result is a bit
61  * mask in the first byte of active/available fans, followed by 6 words (16
62  * bits) containing the requested speed.
63  *
64  * Setpoint (14 bytes arg):
65  * ------------------------
66  *
67  * first arg byte is 0 for RPM fans and 0x10 for PWM. Second arg byte is the
68  * mask of fans affected by the command. Followed by 6 words containing the
69  * setpoint value for selected fans in the mask (or 0 if mask value is 0)
70  */
71 #define SMU_CMD_FAN_COMMAND			0x4a
72 
73 
74 /*
75  * Battery access
76  *
77  * Same command number as the PMU, could it be same syntax ?
78  */
79 #define SMU_CMD_BATTERY_COMMAND			0x6f
80 #define   SMU_CMD_GET_BATTERY_INFO		0x00
81 
82 /*
83  * Real time clock control
84  *
85  * This is a "mux", first data byte contains the "sub" command.
86  * The "RTC" part of the SMU controls the date, time, powerup
87  * timer, but also a PRAM
88  *
89  * Dates are in BCD format on 7 bytes:
90  * [sec] [min] [hour] [weekday] [month day] [month] [year]
91  * with month being 1 based and year minus 100
92  */
93 #define SMU_CMD_RTC_COMMAND			0x8e
94 #define   SMU_CMD_RTC_SET_PWRUP_TIMER		0x00 /* i: 7 bytes date */
95 #define   SMU_CMD_RTC_GET_PWRUP_TIMER		0x01 /* o: 7 bytes date */
96 #define   SMU_CMD_RTC_STOP_PWRUP_TIMER		0x02
97 #define   SMU_CMD_RTC_SET_PRAM_BYTE_ACC		0x20 /* i: 1 byte (address?) */
98 #define   SMU_CMD_RTC_SET_PRAM_AUTOINC		0x21 /* i: 1 byte (data?) */
99 #define   SMU_CMD_RTC_SET_PRAM_LO_BYTES 	0x22 /* i: 10 bytes */
100 #define   SMU_CMD_RTC_SET_PRAM_HI_BYTES 	0x23 /* i: 10 bytes */
101 #define   SMU_CMD_RTC_GET_PRAM_BYTE		0x28 /* i: 1 bytes (address?) */
102 #define   SMU_CMD_RTC_GET_PRAM_LO_BYTES 	0x29 /* o: 10 bytes */
103 #define   SMU_CMD_RTC_GET_PRAM_HI_BYTES 	0x2a /* o: 10 bytes */
104 #define	  SMU_CMD_RTC_SET_DATETIME		0x80 /* i: 7 bytes date */
105 #define   SMU_CMD_RTC_GET_DATETIME		0x81 /* o: 7 bytes date */
106 
107  /*
108   * i2c commands
109   *
110   * To issue an i2c command, first is to send a parameter block to the
111   * the SMU. This is a command of type 0x9a with 9 bytes of header
112   * eventually followed by data for a write:
113   *
114   * 0: bus number (from device-tree usually, SMU has lots of busses !)
115   * 1: transfer type/format (see below)
116   * 2: device address. For combined and combined4 type transfers, this
117   *    is the "write" version of the address (bit 0x01 cleared)
118   * 3: subaddress length (0..3)
119   * 4: subaddress byte 0 (or only byte for subaddress length 1)
120   * 5: subaddress byte 1
121   * 6: subaddress byte 2
122   * 7: combined address (device address for combined mode data phase)
123   * 8: data length
124   *
125   * The transfer types are the same good old Apple ones it seems,
126   * that is:
127   *   - 0x00: Simple transfer
128   *   - 0x01: Subaddress transfer (addr write + data tx, no restart)
129   *   - 0x02: Combined transfer (addr write + restart + data tx)
130   *
131   * This is then followed by actual data for a write.
132   *
133   * At this point, the OF driver seems to have a limitation on transfer
134   * sizes of 0xd bytes on reads and 0x5 bytes on writes. I do not know
135   * whether this is just an OF limit due to some temporary buffer size
136   * or if this is an SMU imposed limit. This driver has the same limitation
137   * for now as I use a 0x10 bytes temporary buffer as well
138   *
139   * Once that is completed, a response is expected from the SMU. This is
140   * obtained via a command of type 0x9a with a length of 1 byte containing
141   * 0 as the data byte. OF also fills the rest of the data buffer with 0xff's
142   * though I can't tell yet if this is actually necessary. Once this command
143   * is complete, at this point, all I can tell is what OF does. OF tests
144   * byte 0 of the reply:
145   *   - on read, 0xfe or 0xfc : bus is busy, wait (see below) or nak ?
146   *   - on read, 0x00 or 0x01 : reply is in buffer (after the byte 0)
147   *   - on write, < 0 -> failure (immediate exit)
148   *   - else, OF just exists (without error, weird)
149   *
150   * So on read, there is this wait-for-busy thing when getting a 0xfc or
151   * 0xfe result. OF does a loop of up to 64 retries, waiting 20ms and
152   * doing the above again until either the retries expire or the result
153   * is no longer 0xfe or 0xfc
154   *
155   * The Darwin I2C driver is less subtle though. On any non-success status
156   * from the response command, it waits 5ms and tries again up to 20 times,
157   * it doesn't differenciate between fatal errors or "busy" status.
158   *
159   * This driver provides an asynchronous paramblock based i2c command
160   * interface to be used either directly by low level code or by a higher
161   * level driver interfacing to the linux i2c layer. The current
162   * implementation of this relies on working timers & timer interrupts
163   * though, so be careful of calling context for now. This may be "fixed"
164   * in the future by adding a polling facility.
165   */
166 #define SMU_CMD_I2C_COMMAND			0x9a
167           /* transfer types */
168 #define   SMU_I2C_TRANSFER_SIMPLE	0x00
169 #define   SMU_I2C_TRANSFER_STDSUB	0x01
170 #define   SMU_I2C_TRANSFER_COMBINED	0x02
171 
172 /*
173  * Power supply control
174  *
175  * The "sub" command is an ASCII string in the data, the
176  * data length is that of the string.
177  *
178  * The VSLEW command can be used to get or set the voltage slewing.
179  *  - length 5 (only "VSLEW") : it returns "DONE" and 3 bytes of
180  *    reply at data offset 6, 7 and 8.
181  *  - length 8 ("VSLEWxyz") has 3 additional bytes appended, and is
182  *    used to set the voltage slewing point. The SMU replies with "DONE"
183  * I yet have to figure out their exact meaning of those 3 bytes in
184  * both cases. They seem to be:
185  *  x = processor mask
186  *  y = op. point index
187  *  z = processor freq. step index
188  * I haven't yet decyphered result codes
189  *
190  */
191 #define SMU_CMD_POWER_COMMAND			0xaa
192 #define   SMU_CMD_POWER_RESTART		       	"RESTART"
193 #define   SMU_CMD_POWER_SHUTDOWN		"SHUTDOWN"
194 #define   SMU_CMD_POWER_VOLTAGE_SLEW		"VSLEW"
195 
196 /*
197  * Read ADC sensors
198  *
199  * This command takes one byte of parameter: the sensor ID (or "reg"
200  * value in the device-tree) and returns a 16 bits value
201  */
202 #define SMU_CMD_READ_ADC			0xd8
203 
204 
205 /* Misc commands
206  *
207  * This command seem to be a grab bag of various things
208  *
209  * Parameters:
210  *   1: subcommand
211  */
212 #define SMU_CMD_MISC_df_COMMAND			0xdf
213 
214 /*
215  * Sets "system ready" status
216  *
217  * I did not yet understand how it exactly works or what it does.
218  *
219  * Guessing from OF code, 0x02 activates the display backlight. Apple uses/used
220  * the same codebase for all OF versions. On PowerBooks, this command would
221  * enable the backlight. For the G5s, it only activates the front LED. However,
222  * don't take this for granted.
223  *
224  * Parameters:
225  *   2: status [0x00, 0x01 or 0x02]
226  */
227 #define   SMU_CMD_MISC_df_SET_DISPLAY_LIT	0x02
228 
229 /*
230  * Sets mode of power switch.
231  *
232  * What this actually does is not yet known. Maybe it enables some interrupt.
233  *
234  * Parameters:
235  *   2: enable power switch? [0x00 or 0x01]
236  *   3 (optional): enable nmi? [0x00 or 0x01]
237  *
238  * Returns:
239  *   If parameter 2 is 0x00 and parameter 3 is not specified, returns whether
240  *   NMI is enabled. Otherwise unknown.
241  */
242 #define   SMU_CMD_MISC_df_NMI_OPTION		0x04
243 
244 /* Sets LED dimm offset.
245  *
246  * The front LED dimms itself during sleep. Its brightness (or, well, the PWM
247  * frequency) depends on current time. Therefore, the SMU needs to know the
248  * timezone.
249  *
250  * Parameters:
251  *   2-8: unknown (BCD coding)
252  */
253 #define   SMU_CMD_MISC_df_DIMM_OFFSET		0x99
254 
255 
256 /*
257  * Version info commands
258  *
259  * Parameters:
260  *   1 (optional): Specifies version part to retrieve
261  *
262  * Returns:
263  *   Version value
264  */
265 #define SMU_CMD_VERSION_COMMAND			0xea
266 #define   SMU_VERSION_RUNNING			0x00
267 #define   SMU_VERSION_BASE			0x01
268 #define   SMU_VERSION_UPDATE			0x02
269 
270 
271 /*
272  * Switches
273  *
274  * These are switches whose status seems to be known to the SMU.
275  *
276  * Parameters:
277  *   none
278  *
279  * Result:
280  *   Switch bits (ORed, see below)
281  */
282 #define SMU_CMD_SWITCHES			0xdc
283 
284 /* Switches bits */
285 #define SMU_SWITCH_CASE_CLOSED			0x01
286 #define SMU_SWITCH_AC_POWER			0x04
287 #define SMU_SWITCH_POWER_SWITCH			0x08
288 
289 
290 /*
291  * Misc commands
292  *
293  * This command seem to be a grab bag of various things
294  *
295  * SMU_CMD_MISC_ee_GET_DATABLOCK_REC is used, among others, to
296  * transfer blocks of data from the SMU. So far, I've decrypted it's
297  * usage to retrieve partition data. In order to do that, you have to
298  * break your transfer in "chunks" since that command cannot transfer
299  * more than a chunk at a time. The chunk size used by OF is 0xe bytes,
300  * but it seems that the darwin driver will let you do 0x1e bytes if
301  * your "PMU" version is >= 0x30. You can get the "PMU" version apparently
302  * either in the last 16 bits of property "smu-version-pmu" or as the 16
303  * bytes at offset 1 of "smu-version-info"
304  *
305  * For each chunk, the command takes 7 bytes of arguments:
306  *  byte 0: subcommand code (0x02)
307  *  byte 1: 0x04 (always, I don't know what it means, maybe the address
308  *                space to use or some other nicety. It's hard coded in OF)
309  *  byte 2..5: SMU address of the chunk (big endian 32 bits)
310  *  byte 6: size to transfer (up to max chunk size)
311  *
312  * The data is returned directly
313  */
314 #define SMU_CMD_MISC_ee_COMMAND			0xee
315 #define   SMU_CMD_MISC_ee_GET_DATABLOCK_REC	0x02
316 
317 /* Retrieves currently used watts.
318  *
319  * Parameters:
320  *   1: 0x03 (Meaning unknown)
321  */
322 #define   SMU_CMD_MISC_ee_GET_WATTS		0x03
323 
324 #define   SMU_CMD_MISC_ee_LEDS_CTRL		0x04 /* i: 00 (00,01) [00] */
325 #define   SMU_CMD_MISC_ee_GET_DATA		0x05 /* i: 00 , o: ?? */
326 
327 
328 /*
329  * Power related commands
330  *
331  * Parameters:
332  *   1: subcommand
333  */
334 #define SMU_CMD_POWER_EVENTS_COMMAND		0x8f
335 
336 /* SMU_POWER_EVENTS subcommands */
337 enum {
338 	SMU_PWR_GET_POWERUP_EVENTS      = 0x00,
339 	SMU_PWR_SET_POWERUP_EVENTS      = 0x01,
340 	SMU_PWR_CLR_POWERUP_EVENTS      = 0x02,
341 	SMU_PWR_GET_WAKEUP_EVENTS       = 0x03,
342 	SMU_PWR_SET_WAKEUP_EVENTS       = 0x04,
343 	SMU_PWR_CLR_WAKEUP_EVENTS       = 0x05,
344 
345 	/*
346 	 * Get last shutdown cause
347 	 *
348 	 * Returns:
349 	 *   1 byte (signed char): Last shutdown cause. Exact meaning unknown.
350 	 */
351 	SMU_PWR_LAST_SHUTDOWN_CAUSE	= 0x07,
352 
353 	/*
354 	 * Sets or gets server ID. Meaning or use is unknown.
355 	 *
356 	 * Parameters:
357 	 *   2 (optional): Set server ID (1 byte)
358 	 *
359 	 * Returns:
360 	 *   1 byte (server ID?)
361 	 */
362 	SMU_PWR_SERVER_ID		= 0x08,
363 };
364 
365 /* Power events wakeup bits */
366 enum {
367 	SMU_PWR_WAKEUP_KEY              = 0x01, /* Wake on key press */
368 	SMU_PWR_WAKEUP_AC_INSERT        = 0x02, /* Wake on AC adapter plug */
369 	SMU_PWR_WAKEUP_AC_CHANGE        = 0x04,
370 	SMU_PWR_WAKEUP_LID_OPEN         = 0x08,
371 	SMU_PWR_WAKEUP_RING             = 0x10,
372 };
373 
374 
375 /*
376  * - Kernel side interface -
377  */
378 
379 #ifdef __KERNEL__
380 
381 /*
382  * Asynchronous SMU commands
383  *
384  * Fill up this structure and submit it via smu_queue_command(),
385  * and get notified by the optional done() callback, or because
386  * status becomes != 1
387  */
388 
389 struct smu_cmd;
390 
391 struct smu_cmd
392 {
393 	/* public */
394 	u8			cmd;		/* command */
395 	int			data_len;	/* data len */
396 	int			reply_len;	/* reply len */
397 	void			*data_buf;	/* data buffer */
398 	void			*reply_buf;	/* reply buffer */
399 	int			status;		/* command status */
400 	void			(*done)(struct smu_cmd *cmd, void *misc);
401 	void			*misc;
402 
403 	/* private */
404 	struct list_head	link;
405 };
406 
407 /*
408  * Queues an SMU command, all fields have to be initialized
409  */
410 extern int smu_queue_cmd(struct smu_cmd *cmd);
411 
412 /*
413  * Simple command wrapper. This structure embeds a small buffer
414  * to ease sending simple SMU commands from the stack
415  */
416 struct smu_simple_cmd
417 {
418 	struct smu_cmd	cmd;
419 	u8	       	buffer[16];
420 };
421 
422 /*
423  * Queues a simple command. All fields will be initialized by that
424  * function
425  */
426 extern int smu_queue_simple(struct smu_simple_cmd *scmd, u8 command,
427 			    unsigned int data_len,
428 			    void (*done)(struct smu_cmd *cmd, void *misc),
429 			    void *misc,
430 			    ...);
431 
432 /*
433  * Completion helper. Pass it to smu_queue_simple or as 'done'
434  * member to smu_queue_cmd, it will call complete() on the struct
435  * completion passed in the "misc" argument
436  */
437 extern void smu_done_complete(struct smu_cmd *cmd, void *misc);
438 
439 /*
440  * Synchronous helpers. Will spin-wait for completion of a command
441  */
442 extern void smu_spinwait_cmd(struct smu_cmd *cmd);
443 
444 static inline void smu_spinwait_simple(struct smu_simple_cmd *scmd)
445 {
446 	smu_spinwait_cmd(&scmd->cmd);
447 }
448 
449 /*
450  * Poll routine to call if blocked with irqs off
451  */
452 extern void smu_poll(void);
453 
454 
455 /*
456  * Init routine, presence check....
457  */
458 extern int smu_init(void);
459 extern int smu_present(void);
460 struct platform_device;
461 extern struct platform_device *smu_get_ofdev(void);
462 
463 
464 /*
465  * Common command wrappers
466  */
467 extern void smu_shutdown(void);
468 extern void smu_restart(void);
469 struct rtc_time;
470 extern int smu_get_rtc_time(struct rtc_time *time, int spinwait);
471 extern int smu_set_rtc_time(struct rtc_time *time, int spinwait);
472 
473 /*
474  * SMU command buffer absolute address, exported by pmac_setup,
475  * this is allocated very early during boot.
476  */
477 extern unsigned long smu_cmdbuf_abs;
478 
479 
480 /*
481  * Kenrel asynchronous i2c interface
482  */
483 
484 #define SMU_I2C_READ_MAX	0x1d
485 #define SMU_I2C_WRITE_MAX	0x15
486 
487 /* SMU i2c header, exactly matches i2c header on wire */
488 struct smu_i2c_param
489 {
490 	u8	bus;		/* SMU bus ID (from device tree) */
491 	u8	type;		/* i2c transfer type */
492 	u8	devaddr;	/* device address (includes direction) */
493 	u8	sublen;		/* subaddress length */
494 	u8	subaddr[3];	/* subaddress */
495 	u8	caddr;		/* combined address, filled by SMU driver */
496 	u8	datalen;	/* length of transfer */
497 	u8	data[SMU_I2C_READ_MAX];	/* data */
498 };
499 
500 struct smu_i2c_cmd
501 {
502 	/* public */
503 	struct smu_i2c_param	info;
504 	void			(*done)(struct smu_i2c_cmd *cmd, void *misc);
505 	void			*misc;
506 	int			status; /* 1 = pending, 0 = ok, <0 = fail */
507 
508 	/* private */
509 	struct smu_cmd		scmd;
510 	int			read;
511 	int			stage;
512 	int			retries;
513 	u8			pdata[32];
514 	struct list_head	link;
515 };
516 
517 /*
518  * Call this to queue an i2c command to the SMU. You must fill info,
519  * including info.data for a write, done and misc.
520  * For now, no polling interface is provided so you have to use completion
521  * callback.
522  */
523 extern int smu_queue_i2c(struct smu_i2c_cmd *cmd);
524 
525 
526 #endif /* __KERNEL__ */
527 
528 
529 /*
530  * - SMU "sdb" partitions informations -
531  */
532 
533 
534 /*
535  * Partition header format
536  */
537 struct smu_sdbp_header {
538 	__u8	id;
539 	__u8	len;
540 	__u8	version;
541 	__u8	flags;
542 };
543 
544 
545  /*
546  * demangle 16 and 32 bits integer in some SMU partitions
547  * (currently, afaik, this concerns only the FVT partition
548  * (0x12)
549  */
550 #define SMU_U16_MIX(x)	le16_to_cpu(x)
551 #define SMU_U32_MIX(x)  ((((x) & 0xff00ff00u) >> 8)|(((x) & 0x00ff00ffu) << 8))
552 
553 
554 /* This is the definition of the SMU sdb-partition-0x12 table (called
555  * CPU F/V/T operating points in Darwin). The definition for all those
556  * SMU tables should be moved to some separate file
557  */
558 #define SMU_SDB_FVT_ID			0x12
559 
560 struct smu_sdbp_fvt {
561 	__u32	sysclk;			/* Base SysClk frequency in Hz for
562 					 * this operating point. Value need to
563 					 * be unmixed with SMU_U32_MIX()
564 					 */
565 	__u8	pad;
566 	__u8	maxtemp;		/* Max temp. supported by this
567 					 * operating point
568 					 */
569 
570 	__u16	volts[3];		/* CPU core voltage for the 3
571 					 * PowerTune modes, a mode with
572 					 * 0V = not supported. Value need
573 					 * to be unmixed with SMU_U16_MIX()
574 					 */
575 };
576 
577 /* This partition contains voltage & current sensor calibration
578  * informations
579  */
580 #define SMU_SDB_CPUVCP_ID		0x21
581 
582 struct smu_sdbp_cpuvcp {
583 	__u16	volt_scale;		/* u4.12 fixed point */
584 	__s16	volt_offset;		/* s4.12 fixed point */
585 	__u16	curr_scale;		/* u4.12 fixed point */
586 	__s16	curr_offset;		/* s4.12 fixed point */
587 	__s32	power_quads[3];		/* s4.28 fixed point */
588 };
589 
590 /* This partition contains CPU thermal diode calibration
591  */
592 #define SMU_SDB_CPUDIODE_ID		0x18
593 
594 struct smu_sdbp_cpudiode {
595 	__u16	m_value;		/* u1.15 fixed point */
596 	__s16	b_value;		/* s10.6 fixed point */
597 
598 };
599 
600 /* This partition contains Slots power calibration
601  */
602 #define SMU_SDB_SLOTSPOW_ID		0x78
603 
604 struct smu_sdbp_slotspow {
605 	__u16	pow_scale;		/* u4.12 fixed point */
606 	__s16	pow_offset;		/* s4.12 fixed point */
607 };
608 
609 /* This partition contains machine specific version information about
610  * the sensor/control layout
611  */
612 #define SMU_SDB_SENSORTREE_ID		0x25
613 
614 struct smu_sdbp_sensortree {
615 	__u8	model_id;
616 	__u8	unknown[3];
617 };
618 
619 /* This partition contains CPU thermal control PID informations. So far
620  * only single CPU machines have been seen with an SMU, so we assume this
621  * carries only informations for those
622  */
623 #define SMU_SDB_CPUPIDDATA_ID		0x17
624 
625 struct smu_sdbp_cpupiddata {
626 	__u8	unknown1;
627 	__u8	target_temp_delta;
628 	__u8	unknown2;
629 	__u8	history_len;
630 	__s16	power_adj;
631 	__u16	max_power;
632 	__s32	gp,gr,gd;
633 };
634 
635 
636 /* Other partitions without known structures */
637 #define SMU_SDB_DEBUG_SWITCHES_ID	0x05
638 
639 #ifdef __KERNEL__
640 /*
641  * This returns the pointer to an SMU "sdb" partition data or NULL
642  * if not found. The data format is described below
643  */
644 extern const struct smu_sdbp_header *smu_get_sdb_partition(int id,
645 					unsigned int *size);
646 
647 /* Get "sdb" partition data from an SMU satellite */
648 extern struct smu_sdbp_header *smu_sat_get_sdb_partition(unsigned int sat_id,
649 					int id, unsigned int *size);
650 
651 
652 #endif /* __KERNEL__ */
653 
654 
655 /*
656  * - Userland interface -
657  */
658 
659 /*
660  * A given instance of the device can be configured for 2 different
661  * things at the moment:
662  *
663  *  - sending SMU commands (default at open() time)
664  *  - receiving SMU events (not yet implemented)
665  *
666  * Commands are written with write() of a command block. They can be
667  * "driver" commands (for example to switch to event reception mode)
668  * or real SMU commands. They are made of a header followed by command
669  * data if any.
670  *
671  * For SMU commands (not for driver commands), you can then read() back
672  * a reply. The reader will be blocked or not depending on how the device
673  * file is opened. poll() isn't implemented yet. The reply will consist
674  * of a header as well, followed by the reply data if any. You should
675  * always provide a buffer large enough for the maximum reply data, I
676  * recommand one page.
677  *
678  * It is illegal to send SMU commands through a file descriptor configured
679  * for events reception
680  *
681  */
682 struct smu_user_cmd_hdr
683 {
684 	__u32		cmdtype;
685 #define SMU_CMDTYPE_SMU			0	/* SMU command */
686 #define SMU_CMDTYPE_WANTS_EVENTS	1	/* switch fd to events mode */
687 #define SMU_CMDTYPE_GET_PARTITION	2	/* retrieve an sdb partition */
688 
689 	__u8		cmd;			/* SMU command byte */
690 	__u8		pad[3];			/* padding */
691 	__u32		data_len;		/* Length of data following */
692 };
693 
694 struct smu_user_reply_hdr
695 {
696 	__u32		status;			/* Command status */
697 	__u32		reply_len;		/* Length of data follwing */
698 };
699 
700 #endif /*  _SMU_H */
701