1 /*
2  * ePAPR hcall interface
3  *
4  * Copyright 2008-2011 Freescale Semiconductor, Inc.
5  *
6  * Author: Timur Tabi <timur@freescale.com>
7  *
8  * This file is provided under a dual BSD/GPL license.  When using or
9  * redistributing this file, you may do so under either license.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions are met:
13  *     * Redistributions of source code must retain the above copyright
14  *       notice, this list of conditions and the following disclaimer.
15  *     * Redistributions in binary form must reproduce the above copyright
16  *       notice, this list of conditions and the following disclaimer in the
17  *       documentation and/or other materials provided with the distribution.
18  *     * Neither the name of Freescale Semiconductor nor the
19  *       names of its contributors may be used to endorse or promote products
20  *       derived from this software without specific prior written permission.
21  *
22  *
23  * ALTERNATIVELY, this software may be distributed under the terms of the
24  * GNU General Public License ("GPL") as published by the Free Software
25  * Foundation, either version 2 of that License or (at your option) any
26  * later version.
27  *
28  * THIS SOFTWARE IS PROVIDED BY Freescale Semiconductor ``AS IS'' AND ANY
29  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
30  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
31  * DISCLAIMED. IN NO EVENT SHALL Freescale Semiconductor BE LIABLE FOR ANY
32  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
33  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
34  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
35  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
37  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 /* A "hypercall" is an "sc 1" instruction.  This header file provides C
41  * wrapper functions for the ePAPR hypervisor interface.  It is inteded
42  * for use by Linux device drivers and other operating systems.
43  *
44  * The hypercalls are implemented as inline assembly, rather than assembly
45  * language functions in a .S file, for optimization.  It allows
46  * the caller to issue the hypercall instruction directly, improving both
47  * performance and memory footprint.
48  */
49 
50 #ifndef _EPAPR_HCALLS_H
51 #define _EPAPR_HCALLS_H
52 
53 #include <uapi/asm/epapr_hcalls.h>
54 
55 #ifndef __ASSEMBLY__
56 #include <linux/types.h>
57 #include <linux/errno.h>
58 #include <asm/byteorder.h>
59 
60 /*
61  * Hypercall register clobber list
62  *
63  * These macros are used to define the list of clobbered registers during a
64  * hypercall.  Technically, registers r0 and r3-r12 are always clobbered,
65  * but the gcc inline assembly syntax does not allow us to specify registers
66  * on the clobber list that are also on the input/output list.  Therefore,
67  * the lists of clobbered registers depends on the number of register
68  * parmeters ("+r" and "=r") passed to the hypercall.
69  *
70  * Each assembly block should use one of the HCALL_CLOBBERSx macros.  As a
71  * general rule, 'x' is the number of parameters passed to the assembly
72  * block *except* for r11.
73  *
74  * If you're not sure, just use the smallest value of 'x' that does not
75  * generate a compilation error.  Because these are static inline functions,
76  * the compiler will only check the clobber list for a function if you
77  * compile code that calls that function.
78  *
79  * r3 and r11 are not included in any clobbers list because they are always
80  * listed as output registers.
81  *
82  * XER, CTR, and LR are currently listed as clobbers because it's uncertain
83  * whether they will be clobbered.
84  *
85  * Note that r11 can be used as an output parameter.
86  *
87  * The "memory" clobber is only necessary for hcalls where the Hypervisor
88  * will read or write guest memory. However, we add it to all hcalls because
89  * the impact is minimal, and we want to ensure that it's present for the
90  * hcalls that need it.
91 */
92 
93 /* List of common clobbered registers.  Do not use this macro. */
94 #define EV_HCALL_CLOBBERS "r0", "r12", "xer", "ctr", "lr", "cc", "memory"
95 
96 #define EV_HCALL_CLOBBERS8 EV_HCALL_CLOBBERS
97 #define EV_HCALL_CLOBBERS7 EV_HCALL_CLOBBERS8, "r10"
98 #define EV_HCALL_CLOBBERS6 EV_HCALL_CLOBBERS7, "r9"
99 #define EV_HCALL_CLOBBERS5 EV_HCALL_CLOBBERS6, "r8"
100 #define EV_HCALL_CLOBBERS4 EV_HCALL_CLOBBERS5, "r7"
101 #define EV_HCALL_CLOBBERS3 EV_HCALL_CLOBBERS4, "r6"
102 #define EV_HCALL_CLOBBERS2 EV_HCALL_CLOBBERS3, "r5"
103 #define EV_HCALL_CLOBBERS1 EV_HCALL_CLOBBERS2, "r4"
104 
105 extern bool epapr_paravirt_enabled;
106 extern u32 epapr_hypercall_start[];
107 
108 #ifdef CONFIG_EPAPR_PARAVIRT
109 int __init epapr_paravirt_early_init(void);
110 #else
111 static inline int epapr_paravirt_early_init(void) { return 0; }
112 #endif
113 
114 /*
115  * We use "uintptr_t" to define a register because it's guaranteed to be a
116  * 32-bit integer on a 32-bit platform, and a 64-bit integer on a 64-bit
117  * platform.
118  *
119  * All registers are either input/output or output only.  Registers that are
120  * initialized before making the hypercall are input/output.  All
121  * input/output registers are represented with "+r".  Output-only registers
122  * are represented with "=r".  Do not specify any unused registers.  The
123  * clobber list will tell the compiler that the hypercall modifies those
124  * registers, which is good enough.
125  */
126 
127 /**
128  * ev_int_set_config - configure the specified interrupt
129  * @interrupt: the interrupt number
130  * @config: configuration for this interrupt
131  * @priority: interrupt priority
132  * @destination: destination CPU number
133  *
134  * Returns 0 for success, or an error code.
135  */
136 static inline unsigned int ev_int_set_config(unsigned int interrupt,
137 	uint32_t config, unsigned int priority, uint32_t destination)
138 {
139 	register uintptr_t r11 __asm__("r11");
140 	register uintptr_t r3 __asm__("r3");
141 	register uintptr_t r4 __asm__("r4");
142 	register uintptr_t r5 __asm__("r5");
143 	register uintptr_t r6 __asm__("r6");
144 
145 	r11 = EV_HCALL_TOKEN(EV_INT_SET_CONFIG);
146 	r3  = interrupt;
147 	r4  = config;
148 	r5  = priority;
149 	r6  = destination;
150 
151 	asm volatile("bl	epapr_hypercall_start"
152 		: "+r" (r11), "+r" (r3), "+r" (r4), "+r" (r5), "+r" (r6)
153 		: : EV_HCALL_CLOBBERS4
154 	);
155 
156 	return r3;
157 }
158 
159 /**
160  * ev_int_get_config - return the config of the specified interrupt
161  * @interrupt: the interrupt number
162  * @config: returned configuration for this interrupt
163  * @priority: returned interrupt priority
164  * @destination: returned destination CPU number
165  *
166  * Returns 0 for success, or an error code.
167  */
168 static inline unsigned int ev_int_get_config(unsigned int interrupt,
169 	uint32_t *config, unsigned int *priority, uint32_t *destination)
170 {
171 	register uintptr_t r11 __asm__("r11");
172 	register uintptr_t r3 __asm__("r3");
173 	register uintptr_t r4 __asm__("r4");
174 	register uintptr_t r5 __asm__("r5");
175 	register uintptr_t r6 __asm__("r6");
176 
177 	r11 = EV_HCALL_TOKEN(EV_INT_GET_CONFIG);
178 	r3 = interrupt;
179 
180 	asm volatile("bl	epapr_hypercall_start"
181 		: "+r" (r11), "+r" (r3), "=r" (r4), "=r" (r5), "=r" (r6)
182 		: : EV_HCALL_CLOBBERS4
183 	);
184 
185 	*config = r4;
186 	*priority = r5;
187 	*destination = r6;
188 
189 	return r3;
190 }
191 
192 /**
193  * ev_int_set_mask - sets the mask for the specified interrupt source
194  * @interrupt: the interrupt number
195  * @mask: 0=enable interrupts, 1=disable interrupts
196  *
197  * Returns 0 for success, or an error code.
198  */
199 static inline unsigned int ev_int_set_mask(unsigned int interrupt,
200 	unsigned int mask)
201 {
202 	register uintptr_t r11 __asm__("r11");
203 	register uintptr_t r3 __asm__("r3");
204 	register uintptr_t r4 __asm__("r4");
205 
206 	r11 = EV_HCALL_TOKEN(EV_INT_SET_MASK);
207 	r3 = interrupt;
208 	r4 = mask;
209 
210 	asm volatile("bl	epapr_hypercall_start"
211 		: "+r" (r11), "+r" (r3), "+r" (r4)
212 		: : EV_HCALL_CLOBBERS2
213 	);
214 
215 	return r3;
216 }
217 
218 /**
219  * ev_int_get_mask - returns the mask for the specified interrupt source
220  * @interrupt: the interrupt number
221  * @mask: returned mask for this interrupt (0=enabled, 1=disabled)
222  *
223  * Returns 0 for success, or an error code.
224  */
225 static inline unsigned int ev_int_get_mask(unsigned int interrupt,
226 	unsigned int *mask)
227 {
228 	register uintptr_t r11 __asm__("r11");
229 	register uintptr_t r3 __asm__("r3");
230 	register uintptr_t r4 __asm__("r4");
231 
232 	r11 = EV_HCALL_TOKEN(EV_INT_GET_MASK);
233 	r3 = interrupt;
234 
235 	asm volatile("bl	epapr_hypercall_start"
236 		: "+r" (r11), "+r" (r3), "=r" (r4)
237 		: : EV_HCALL_CLOBBERS2
238 	);
239 
240 	*mask = r4;
241 
242 	return r3;
243 }
244 
245 /**
246  * ev_int_eoi - signal the end of interrupt processing
247  * @interrupt: the interrupt number
248  *
249  * This function signals the end of processing for the specified
250  * interrupt, which must be the interrupt currently in service. By
251  * definition, this is also the highest-priority interrupt.
252  *
253  * Returns 0 for success, or an error code.
254  */
255 static inline unsigned int ev_int_eoi(unsigned int interrupt)
256 {
257 	register uintptr_t r11 __asm__("r11");
258 	register uintptr_t r3 __asm__("r3");
259 
260 	r11 = EV_HCALL_TOKEN(EV_INT_EOI);
261 	r3 = interrupt;
262 
263 	asm volatile("bl	epapr_hypercall_start"
264 		: "+r" (r11), "+r" (r3)
265 		: : EV_HCALL_CLOBBERS1
266 	);
267 
268 	return r3;
269 }
270 
271 /**
272  * ev_byte_channel_send - send characters to a byte stream
273  * @handle: byte stream handle
274  * @count: (input) num of chars to send, (output) num chars sent
275  * @buffer: pointer to a 16-byte buffer
276  *
277  * @buffer must be at least 16 bytes long, because all 16 bytes will be
278  * read from memory into registers, even if count < 16.
279  *
280  * Returns 0 for success, or an error code.
281  */
282 static inline unsigned int ev_byte_channel_send(unsigned int handle,
283 	unsigned int *count, const char buffer[EV_BYTE_CHANNEL_MAX_BYTES])
284 {
285 	register uintptr_t r11 __asm__("r11");
286 	register uintptr_t r3 __asm__("r3");
287 	register uintptr_t r4 __asm__("r4");
288 	register uintptr_t r5 __asm__("r5");
289 	register uintptr_t r6 __asm__("r6");
290 	register uintptr_t r7 __asm__("r7");
291 	register uintptr_t r8 __asm__("r8");
292 	const uint32_t *p = (const uint32_t *) buffer;
293 
294 	r11 = EV_HCALL_TOKEN(EV_BYTE_CHANNEL_SEND);
295 	r3 = handle;
296 	r4 = *count;
297 	r5 = be32_to_cpu(p[0]);
298 	r6 = be32_to_cpu(p[1]);
299 	r7 = be32_to_cpu(p[2]);
300 	r8 = be32_to_cpu(p[3]);
301 
302 	asm volatile("bl	epapr_hypercall_start"
303 		: "+r" (r11), "+r" (r3),
304 		  "+r" (r4), "+r" (r5), "+r" (r6), "+r" (r7), "+r" (r8)
305 		: : EV_HCALL_CLOBBERS6
306 	);
307 
308 	*count = r4;
309 
310 	return r3;
311 }
312 
313 /**
314  * ev_byte_channel_receive - fetch characters from a byte channel
315  * @handle: byte channel handle
316  * @count: (input) max num of chars to receive, (output) num chars received
317  * @buffer: pointer to a 16-byte buffer
318  *
319  * The size of @buffer must be at least 16 bytes, even if you request fewer
320  * than 16 characters, because we always write 16 bytes to @buffer.  This is
321  * for performance reasons.
322  *
323  * Returns 0 for success, or an error code.
324  */
325 static inline unsigned int ev_byte_channel_receive(unsigned int handle,
326 	unsigned int *count, char buffer[EV_BYTE_CHANNEL_MAX_BYTES])
327 {
328 	register uintptr_t r11 __asm__("r11");
329 	register uintptr_t r3 __asm__("r3");
330 	register uintptr_t r4 __asm__("r4");
331 	register uintptr_t r5 __asm__("r5");
332 	register uintptr_t r6 __asm__("r6");
333 	register uintptr_t r7 __asm__("r7");
334 	register uintptr_t r8 __asm__("r8");
335 	uint32_t *p = (uint32_t *) buffer;
336 
337 	r11 = EV_HCALL_TOKEN(EV_BYTE_CHANNEL_RECEIVE);
338 	r3 = handle;
339 	r4 = *count;
340 
341 	asm volatile("bl	epapr_hypercall_start"
342 		: "+r" (r11), "+r" (r3), "+r" (r4),
343 		  "=r" (r5), "=r" (r6), "=r" (r7), "=r" (r8)
344 		: : EV_HCALL_CLOBBERS6
345 	);
346 
347 	*count = r4;
348 	p[0] = cpu_to_be32(r5);
349 	p[1] = cpu_to_be32(r6);
350 	p[2] = cpu_to_be32(r7);
351 	p[3] = cpu_to_be32(r8);
352 
353 	return r3;
354 }
355 
356 /**
357  * ev_byte_channel_poll - returns the status of the byte channel buffers
358  * @handle: byte channel handle
359  * @rx_count: returned count of bytes in receive queue
360  * @tx_count: returned count of free space in transmit queue
361  *
362  * This function reports the amount of data in the receive queue (i.e. the
363  * number of bytes you can read), and the amount of free space in the transmit
364  * queue (i.e. the number of bytes you can write).
365  *
366  * Returns 0 for success, or an error code.
367  */
368 static inline unsigned int ev_byte_channel_poll(unsigned int handle,
369 	unsigned int *rx_count,	unsigned int *tx_count)
370 {
371 	register uintptr_t r11 __asm__("r11");
372 	register uintptr_t r3 __asm__("r3");
373 	register uintptr_t r4 __asm__("r4");
374 	register uintptr_t r5 __asm__("r5");
375 
376 	r11 = EV_HCALL_TOKEN(EV_BYTE_CHANNEL_POLL);
377 	r3 = handle;
378 
379 	asm volatile("bl	epapr_hypercall_start"
380 		: "+r" (r11), "+r" (r3), "=r" (r4), "=r" (r5)
381 		: : EV_HCALL_CLOBBERS3
382 	);
383 
384 	*rx_count = r4;
385 	*tx_count = r5;
386 
387 	return r3;
388 }
389 
390 /**
391  * ev_int_iack - acknowledge an interrupt
392  * @handle: handle to the target interrupt controller
393  * @vector: returned interrupt vector
394  *
395  * If handle is zero, the function returns the next interrupt source
396  * number to be handled irrespective of the hierarchy or cascading
397  * of interrupt controllers. If non-zero, specifies a handle to the
398  * interrupt controller that is the target of the acknowledge.
399  *
400  * Returns 0 for success, or an error code.
401  */
402 static inline unsigned int ev_int_iack(unsigned int handle,
403 	unsigned int *vector)
404 {
405 	register uintptr_t r11 __asm__("r11");
406 	register uintptr_t r3 __asm__("r3");
407 	register uintptr_t r4 __asm__("r4");
408 
409 	r11 = EV_HCALL_TOKEN(EV_INT_IACK);
410 	r3 = handle;
411 
412 	asm volatile("bl	epapr_hypercall_start"
413 		: "+r" (r11), "+r" (r3), "=r" (r4)
414 		: : EV_HCALL_CLOBBERS2
415 	);
416 
417 	*vector = r4;
418 
419 	return r3;
420 }
421 
422 /**
423  * ev_doorbell_send - send a doorbell to another partition
424  * @handle: doorbell send handle
425  *
426  * Returns 0 for success, or an error code.
427  */
428 static inline unsigned int ev_doorbell_send(unsigned int handle)
429 {
430 	register uintptr_t r11 __asm__("r11");
431 	register uintptr_t r3 __asm__("r3");
432 
433 	r11 = EV_HCALL_TOKEN(EV_DOORBELL_SEND);
434 	r3 = handle;
435 
436 	asm volatile("bl	epapr_hypercall_start"
437 		: "+r" (r11), "+r" (r3)
438 		: : EV_HCALL_CLOBBERS1
439 	);
440 
441 	return r3;
442 }
443 
444 /**
445  * ev_idle -- wait for next interrupt on this core
446  *
447  * Returns 0 for success, or an error code.
448  */
449 static inline unsigned int ev_idle(void)
450 {
451 	register uintptr_t r11 __asm__("r11");
452 	register uintptr_t r3 __asm__("r3");
453 
454 	r11 = EV_HCALL_TOKEN(EV_IDLE);
455 
456 	asm volatile("bl	epapr_hypercall_start"
457 		: "+r" (r11), "=r" (r3)
458 		: : EV_HCALL_CLOBBERS1
459 	);
460 
461 	return r3;
462 }
463 
464 #ifdef CONFIG_EPAPR_PARAVIRT
465 static inline unsigned long epapr_hypercall(unsigned long *in,
466 			    unsigned long *out,
467 			    unsigned long nr)
468 {
469 	register unsigned long r0 asm("r0");
470 	register unsigned long r3 asm("r3") = in[0];
471 	register unsigned long r4 asm("r4") = in[1];
472 	register unsigned long r5 asm("r5") = in[2];
473 	register unsigned long r6 asm("r6") = in[3];
474 	register unsigned long r7 asm("r7") = in[4];
475 	register unsigned long r8 asm("r8") = in[5];
476 	register unsigned long r9 asm("r9") = in[6];
477 	register unsigned long r10 asm("r10") = in[7];
478 	register unsigned long r11 asm("r11") = nr;
479 	register unsigned long r12 asm("r12");
480 
481 	asm volatile("bl	epapr_hypercall_start"
482 		     : "=r"(r0), "=r"(r3), "=r"(r4), "=r"(r5), "=r"(r6),
483 		       "=r"(r7), "=r"(r8), "=r"(r9), "=r"(r10), "=r"(r11),
484 		       "=r"(r12)
485 		     : "r"(r3), "r"(r4), "r"(r5), "r"(r6), "r"(r7), "r"(r8),
486 		       "r"(r9), "r"(r10), "r"(r11)
487 		     : "memory", "cc", "xer", "ctr", "lr");
488 
489 	out[0] = r4;
490 	out[1] = r5;
491 	out[2] = r6;
492 	out[3] = r7;
493 	out[4] = r8;
494 	out[5] = r9;
495 	out[6] = r10;
496 	out[7] = r11;
497 
498 	return r3;
499 }
500 #else
501 static unsigned long epapr_hypercall(unsigned long *in,
502 				   unsigned long *out,
503 				   unsigned long nr)
504 {
505 	return EV_UNIMPLEMENTED;
506 }
507 #endif
508 
509 static inline long epapr_hypercall0_1(unsigned int nr, unsigned long *r2)
510 {
511 	unsigned long in[8] = {0};
512 	unsigned long out[8];
513 	unsigned long r;
514 
515 	r = epapr_hypercall(in, out, nr);
516 	*r2 = out[0];
517 
518 	return r;
519 }
520 
521 static inline long epapr_hypercall0(unsigned int nr)
522 {
523 	unsigned long in[8] = {0};
524 	unsigned long out[8];
525 
526 	return epapr_hypercall(in, out, nr);
527 }
528 
529 static inline long epapr_hypercall1(unsigned int nr, unsigned long p1)
530 {
531 	unsigned long in[8] = {0};
532 	unsigned long out[8];
533 
534 	in[0] = p1;
535 	return epapr_hypercall(in, out, nr);
536 }
537 
538 static inline long epapr_hypercall2(unsigned int nr, unsigned long p1,
539 				    unsigned long p2)
540 {
541 	unsigned long in[8] = {0};
542 	unsigned long out[8];
543 
544 	in[0] = p1;
545 	in[1] = p2;
546 	return epapr_hypercall(in, out, nr);
547 }
548 
549 static inline long epapr_hypercall3(unsigned int nr, unsigned long p1,
550 				    unsigned long p2, unsigned long p3)
551 {
552 	unsigned long in[8] = {0};
553 	unsigned long out[8];
554 
555 	in[0] = p1;
556 	in[1] = p2;
557 	in[2] = p3;
558 	return epapr_hypercall(in, out, nr);
559 }
560 
561 static inline long epapr_hypercall4(unsigned int nr, unsigned long p1,
562 				    unsigned long p2, unsigned long p3,
563 				    unsigned long p4)
564 {
565 	unsigned long in[8] = {0};
566 	unsigned long out[8];
567 
568 	in[0] = p1;
569 	in[1] = p2;
570 	in[2] = p3;
571 	in[3] = p4;
572 	return epapr_hypercall(in, out, nr);
573 }
574 #endif /* !__ASSEMBLY__ */
575 #endif /* _EPAPR_HCALLS_H */
576