1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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__FBSDID("$FreeBSD$");
31
32#include <sys/endian.h>
33#include <sys/param.h>
34#include <sys/kernel.h>
35#include <sys/lock.h>
36#include <sys/mutex.h>
37#include <sys/systm.h>
38#include <sys/proc.h>
39
40#include <vm/vm.h>
41#include <vm/vm_page.h>
42#include <vm/pmap.h>
43
44#include <machine/bus.h>
45#include <machine/md_var.h>
46#include <machine/pcb.h>
47#include <machine/rtas.h>
48#include <machine/stdarg.h>
49
50#include <dev/ofw/openfirm.h>
51
52static MALLOC_DEFINE(M_RTAS, "rtas", "Run Time Abstraction Service");
53
54static vm_offset_t	rtas_bounce_phys;
55static caddr_t		rtas_bounce_virt;
56static off_t		rtas_bounce_offset;
57static size_t		rtas_bounce_size;
58static uintptr_t	rtas_private_data;
59static struct mtx	rtas_mtx;
60static phandle_t	rtas;
61
62/* From ofwcall.S */
63int rtascall(vm_offset_t callbuffer, uintptr_t rtas_privdat);
64extern uintptr_t	rtas_entry;
65extern register_t	rtasmsr;
66
67/*
68 * After the VM is up, allocate RTAS memory and instantiate it
69 */
70
71static void rtas_setup(void *);
72
73SYSINIT(rtas_setup, SI_SUB_KMEM, SI_ORDER_ANY, rtas_setup, NULL);
74
75static void
76rtas_setup(void *junk)
77{
78	ihandle_t rtasi;
79	cell_t rtas_size = 0, rtas_ptr;
80	char path[31];
81	int result;
82
83	rtas = OF_finddevice("/rtas");
84	if (rtas == -1) {
85		rtas = 0;
86		return;
87	}
88	OF_package_to_path(rtas, path, sizeof(path));
89
90	mtx_init(&rtas_mtx, "RTAS", NULL, MTX_SPIN);
91
92	/* RTAS must be called with everything turned off in MSR */
93	rtasmsr = mfmsr();
94	rtasmsr &= ~(PSL_IR | PSL_DR | PSL_EE | PSL_SE | PSL_LE);
95	#ifdef __powerpc64__
96	rtasmsr &= ~PSL_SF;
97	#endif
98
99	/*
100	 * Allocate rtas_size + one page of contiguous, wired physical memory
101	 * that can fit into a 32-bit address space and accessed from real mode.
102	 * This is used both to bounce arguments and for RTAS private data.
103	 *
104	 * It must be 4KB-aligned and not cross a 256 MB boundary.
105	 */
106
107	OF_getencprop(rtas, "rtas-size", &rtas_size, sizeof(rtas_size));
108	rtas_size = round_page(rtas_size);
109	rtas_bounce_virt = contigmalloc(rtas_size + PAGE_SIZE, M_RTAS, 0, 0,
110	    ulmin(platform_real_maxaddr(), BUS_SPACE_MAXADDR_32BIT),
111	    4096, 256*1024*1024);
112
113	rtas_private_data = vtophys(rtas_bounce_virt);
114	rtas_bounce_virt += rtas_size;	/* Actual bounce area */
115	rtas_bounce_phys = vtophys(rtas_bounce_virt);
116	rtas_bounce_size = PAGE_SIZE;
117
118	/*
119	 * Instantiate RTAS. We always use the 32-bit version.
120	 */
121
122	if (OF_hasprop(rtas, "linux,rtas-entry") &&
123	    OF_hasprop(rtas, "linux,rtas-base")) {
124		OF_getencprop(rtas, "linux,rtas-base", &rtas_ptr,
125		    sizeof(rtas_ptr));
126		rtas_private_data = rtas_ptr;
127		OF_getencprop(rtas, "linux,rtas-entry", &rtas_ptr,
128		    sizeof(rtas_ptr));
129	} else {
130		rtasi = OF_open(path);
131		if (rtasi == 0) {
132			rtas = 0;
133			printf("Error initializing RTAS: could not open "
134			    "node\n");
135			return;
136		}
137
138		result = OF_call_method("instantiate-rtas", rtasi, 1, 1,
139		    (cell_t)rtas_private_data, &rtas_ptr);
140		OF_close(rtasi);
141
142		if (result != 0) {
143			rtas = 0;
144			rtas_ptr = 0;
145			printf("Error initializing RTAS (%d)\n", result);
146			return;
147		}
148	}
149
150	rtas_entry = (uintptr_t)(rtas_ptr);
151}
152
153static cell_t
154rtas_real_map(const void *buf, size_t len)
155{
156	cell_t phys;
157
158	mtx_assert(&rtas_mtx, MA_OWNED);
159
160	/*
161	 * Make sure the bounce page offset satisfies any reasonable
162	 * alignment constraint.
163	 */
164	rtas_bounce_offset += sizeof(register_t) -
165	    (rtas_bounce_offset % sizeof(register_t));
166
167	if (rtas_bounce_offset + len > rtas_bounce_size) {
168		panic("Oversize RTAS call!");
169		return 0;
170	}
171
172	if (buf != NULL)
173		memcpy(rtas_bounce_virt + rtas_bounce_offset, buf, len);
174	else
175		return (0);
176
177	phys = rtas_bounce_phys + rtas_bounce_offset;
178	rtas_bounce_offset += len;
179
180	return (phys);
181}
182
183static void
184rtas_real_unmap(cell_t physaddr, void *buf, size_t len)
185{
186	mtx_assert(&rtas_mtx, MA_OWNED);
187
188	if (physaddr == 0)
189		return;
190
191	memcpy(buf, rtas_bounce_virt + (physaddr - rtas_bounce_phys), len);
192}
193
194/* Check if we have RTAS */
195int
196rtas_exists(void)
197{
198	return (rtas != 0);
199}
200
201/* Call an RTAS method by token */
202int
203rtas_call_method(cell_t token, int nargs, int nreturns, ...)
204{
205	vm_offset_t argsptr;
206	jmp_buf env, *oldfaultbuf;
207	va_list ap;
208	struct {
209		cell_t token;
210		cell_t nargs;
211		cell_t nreturns;
212		cell_t args_n_results[12];
213	} args;
214	int n, result;
215
216	if (!rtas_exists() || nargs + nreturns > 12)
217		return (-1);
218
219	args.token = htobe32(token);
220	va_start(ap, nreturns);
221
222	mtx_lock_spin(&rtas_mtx);
223	rtas_bounce_offset = 0;
224
225	args.nargs = htobe32(nargs);
226	args.nreturns = htobe32(nreturns);
227
228	for (n = 0; n < nargs; n++)
229		args.args_n_results[n] = htobe32(va_arg(ap, cell_t));
230
231	argsptr = rtas_real_map(&args, sizeof(args));
232
233	/* Get rid of any stale machine checks that have been waiting.  */
234	__asm __volatile ("sync; isync");
235	oldfaultbuf = curthread->td_pcb->pcb_onfault;
236	curthread->td_pcb->pcb_onfault = &env;
237	if (!setjmp(env)) {
238		__asm __volatile ("sync");
239		result = rtascall(argsptr, rtas_private_data);
240		__asm __volatile ("sync; isync");
241	} else {
242		result = RTAS_HW_ERROR;
243	}
244	curthread->td_pcb->pcb_onfault = oldfaultbuf;
245	__asm __volatile ("sync");
246
247	rtas_real_unmap(argsptr, &args, sizeof(args));
248	mtx_unlock_spin(&rtas_mtx);
249
250	if (result < 0)
251		return (result);
252
253	for (n = nargs; n < nargs + nreturns; n++)
254		*va_arg(ap, cell_t *) = be32toh(args.args_n_results[n]);
255	return (result);
256}
257
258/* Look up an RTAS token */
259cell_t
260rtas_token_lookup(const char *method)
261{
262	cell_t token;
263
264	if (!rtas_exists())
265		return (-1);
266
267	if (OF_getencprop(rtas, method, &token, sizeof(token)) == -1)
268		return (-1);
269
270	return (token);
271}
272