1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2011 Nathan Whitehorn
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30#include <sys/endian.h>
31#include <sys/param.h>
32#include <sys/kernel.h>
33#include <sys/lock.h>
34#include <sys/mutex.h>
35#include <sys/systm.h>
36#include <sys/proc.h>
37
38#include <vm/vm.h>
39#include <vm/vm_page.h>
40#include <vm/pmap.h>
41
42#include <machine/bus.h>
43#include <machine/md_var.h>
44#include <machine/pcb.h>
45#include <machine/rtas.h>
46#include <machine/stdarg.h>
47
48#include <dev/ofw/openfirm.h>
49
50static MALLOC_DEFINE(M_RTAS, "rtas", "Run Time Abstraction Service");
51
52static vm_offset_t	rtas_bounce_phys;
53static caddr_t		rtas_bounce_virt;
54static off_t		rtas_bounce_offset;
55static size_t		rtas_bounce_size;
56static uintptr_t	rtas_private_data;
57static struct mtx	rtas_mtx;
58static phandle_t	rtas;
59
60/* From ofwcall.S */
61int rtascall(vm_offset_t callbuffer, uintptr_t rtas_privdat);
62extern uintptr_t	rtas_entry;
63extern register_t	rtasmsr;
64
65/*
66 * After the VM is up, allocate RTAS memory and instantiate it
67 */
68
69static void rtas_setup(void *);
70
71SYSINIT(rtas_setup, SI_SUB_KMEM, SI_ORDER_ANY, rtas_setup, NULL);
72
73static void
74rtas_setup(void *junk)
75{
76	ihandle_t rtasi;
77	cell_t rtas_size = 0, rtas_ptr;
78	char path[31];
79	int result;
80
81	rtas = OF_finddevice("/rtas");
82	if (rtas == -1) {
83		rtas = 0;
84		return;
85	}
86	OF_package_to_path(rtas, path, sizeof(path));
87
88	mtx_init(&rtas_mtx, "RTAS", NULL, MTX_SPIN);
89
90	/* RTAS must be called with everything turned off in MSR */
91	rtasmsr = mfmsr();
92	rtasmsr &= ~(PSL_IR | PSL_DR | PSL_EE | PSL_SE | PSL_LE);
93	#ifdef __powerpc64__
94	rtasmsr &= ~PSL_SF;
95	#endif
96
97	/*
98	 * Allocate rtas_size + one page of contiguous, wired physical memory
99	 * that can fit into a 32-bit address space and accessed from real mode.
100	 * This is used both to bounce arguments and for RTAS private data.
101	 *
102	 * It must be 4KB-aligned and not cross a 256 MB boundary.
103	 */
104
105	OF_getencprop(rtas, "rtas-size", &rtas_size, sizeof(rtas_size));
106	rtas_size = round_page(rtas_size);
107	rtas_bounce_virt = contigmalloc(rtas_size + PAGE_SIZE, M_RTAS, 0, 0,
108	    ulmin(platform_real_maxaddr(), BUS_SPACE_MAXADDR_32BIT),
109	    4096, 256*1024*1024);
110
111	rtas_private_data = vtophys(rtas_bounce_virt);
112	rtas_bounce_virt += rtas_size;	/* Actual bounce area */
113	rtas_bounce_phys = vtophys(rtas_bounce_virt);
114	rtas_bounce_size = PAGE_SIZE;
115
116	/*
117	 * Instantiate RTAS. We always use the 32-bit version.
118	 */
119
120	if (OF_hasprop(rtas, "linux,rtas-entry") &&
121	    OF_hasprop(rtas, "linux,rtas-base")) {
122		OF_getencprop(rtas, "linux,rtas-base", &rtas_ptr,
123		    sizeof(rtas_ptr));
124		rtas_private_data = rtas_ptr;
125		OF_getencprop(rtas, "linux,rtas-entry", &rtas_ptr,
126		    sizeof(rtas_ptr));
127	} else {
128		rtasi = OF_open(path);
129		if (rtasi == 0) {
130			rtas = 0;
131			printf("Error initializing RTAS: could not open "
132			    "node\n");
133			return;
134		}
135
136		result = OF_call_method("instantiate-rtas", rtasi, 1, 1,
137		    (cell_t)rtas_private_data, &rtas_ptr);
138		OF_close(rtasi);
139
140		if (result != 0) {
141			rtas = 0;
142			rtas_ptr = 0;
143			printf("Error initializing RTAS (%d)\n", result);
144			return;
145		}
146	}
147
148	rtas_entry = (uintptr_t)(rtas_ptr);
149}
150
151static cell_t
152rtas_real_map(const void *buf, size_t len)
153{
154	cell_t phys;
155
156	mtx_assert(&rtas_mtx, MA_OWNED);
157
158	/*
159	 * Make sure the bounce page offset satisfies any reasonable
160	 * alignment constraint.
161	 */
162	rtas_bounce_offset += sizeof(register_t) -
163	    (rtas_bounce_offset % sizeof(register_t));
164
165	if (rtas_bounce_offset + len > rtas_bounce_size) {
166		panic("Oversize RTAS call!");
167		return 0;
168	}
169
170	if (buf != NULL)
171		memcpy(rtas_bounce_virt + rtas_bounce_offset, buf, len);
172	else
173		return (0);
174
175	phys = rtas_bounce_phys + rtas_bounce_offset;
176	rtas_bounce_offset += len;
177
178	return (phys);
179}
180
181static void
182rtas_real_unmap(cell_t physaddr, void *buf, size_t len)
183{
184	mtx_assert(&rtas_mtx, MA_OWNED);
185
186	if (physaddr == 0)
187		return;
188
189	memcpy(buf, rtas_bounce_virt + (physaddr - rtas_bounce_phys), len);
190}
191
192/* Check if we have RTAS */
193int
194rtas_exists(void)
195{
196	return (rtas != 0);
197}
198
199/* Call an RTAS method by token */
200int
201rtas_call_method(cell_t token, int nargs, int nreturns, ...)
202{
203	vm_offset_t argsptr;
204	jmp_buf env, *oldfaultbuf;
205	va_list ap;
206	struct {
207		cell_t token;
208		cell_t nargs;
209		cell_t nreturns;
210		cell_t args_n_results[12];
211	} args;
212	int n, result;
213
214	if (!rtas_exists() || nargs + nreturns > 12)
215		return (-1);
216
217	args.token = htobe32(token);
218	va_start(ap, nreturns);
219
220	mtx_lock_spin(&rtas_mtx);
221	rtas_bounce_offset = 0;
222
223	args.nargs = htobe32(nargs);
224	args.nreturns = htobe32(nreturns);
225
226	for (n = 0; n < nargs; n++)
227		args.args_n_results[n] = htobe32(va_arg(ap, cell_t));
228
229	argsptr = rtas_real_map(&args, sizeof(args));
230
231	/* Get rid of any stale machine checks that have been waiting.  */
232	__asm __volatile ("sync; isync");
233	oldfaultbuf = curthread->td_pcb->pcb_onfault;
234	curthread->td_pcb->pcb_onfault = &env;
235	if (!setjmp(env)) {
236		__asm __volatile ("sync");
237		result = rtascall(argsptr, rtas_private_data);
238		__asm __volatile ("sync; isync");
239	} else {
240		result = RTAS_HW_ERROR;
241	}
242	curthread->td_pcb->pcb_onfault = oldfaultbuf;
243	__asm __volatile ("sync");
244
245	rtas_real_unmap(argsptr, &args, sizeof(args));
246	mtx_unlock_spin(&rtas_mtx);
247
248	if (result < 0)
249		return (result);
250
251	for (n = nargs; n < nargs + nreturns; n++)
252		*va_arg(ap, cell_t *) = be32toh(args.args_n_results[n]);
253	return (result);
254}
255
256/* Look up an RTAS token */
257cell_t
258rtas_token_lookup(const char *method)
259{
260	cell_t token;
261
262	if (!rtas_exists())
263		return (-1);
264
265	if (OF_getencprop(rtas, method, &token, sizeof(token)) == -1)
266		return (-1);
267
268	return (token);
269}
270