Home | History | Annotate | Line # | Download | only in fdt
fdt_intr.c revision 1.26.4.1
      1 /* $NetBSD: fdt_intr.c,v 1.26.4.1 2021/04/03 22:28:44 thorpej Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2015-2018 Jared McNeill <jmcneill (at) invisible.ca>
      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 ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * 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 __KERNEL_RCSID(0, "$NetBSD: fdt_intr.c,v 1.26.4.1 2021/04/03 22:28:44 thorpej Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/atomic.h>
     34 #include <sys/bus.h>
     35 #include <sys/kmem.h>
     36 #include <sys/queue.h>
     37 #include <sys/mutex.h>
     38 #include <sys/condvar.h>
     39 
     40 #include <libfdt.h>
     41 #include <dev/fdt/fdtvar.h>
     42 #include <dev/fdt/fdt_private.h>
     43 
     44 struct fdtbus_interrupt_controller {
     45 	device_t ic_dev;
     46 	int ic_phandle;
     47 	const struct fdtbus_interrupt_controller_func *ic_funcs;
     48 
     49 	LIST_ENTRY(fdtbus_interrupt_controller) ic_next;
     50 };
     51 
     52 static LIST_HEAD(, fdtbus_interrupt_controller) fdtbus_interrupt_controllers =
     53     LIST_HEAD_INITIALIZER(fdtbus_interrupt_controllers);
     54 
     55 struct fdtbus_interrupt_cookie {
     56 	struct fdtbus_interrupt_controller *c_ic;
     57 	void *c_ih;
     58 
     59 	LIST_ENTRY(fdtbus_interrupt_cookie) c_next;
     60 	uint32_t c_refcnt;
     61 };
     62 
     63 static LIST_HEAD(, fdtbus_interrupt_cookie) fdtbus_interrupt_cookies =
     64     LIST_HEAD_INITIALIZER(fdtbus_interrupt_cookies);
     65 static kmutex_t fdtbus_interrupt_cookie_mutex;
     66 static kcondvar_t fdtbus_interrupt_cookie_wait;
     67 static bool fdtbus_interrupt_cookies_wanted;
     68 
     69 static const u_int *	get_specifier_by_index(int, int, int *);
     70 static const u_int *	get_specifier_from_map(int, const u_int *, int *);
     71 
     72 void
     73 fdtbus_intr_init(void)
     74 {
     75 
     76 	mutex_init(&fdtbus_interrupt_cookie_mutex, MUTEX_DEFAULT, IPL_HIGH);
     77 	cv_init(&fdtbus_interrupt_cookie_wait, "fdtintr");
     78 }
     79 
     80 /*
     81  * Find the interrupt controller for a given node. This function will either
     82  * return the phandle of the interrupt controller for this node, or the phandle
     83  * of a node containing an interrupt-map table that can be used to find the
     84  * real interrupt controller.
     85  */
     86 static int
     87 fdtbus_get_interrupt_parent(int phandle)
     88 {
     89 	int iparent = phandle;
     90 
     91 	do {
     92 		/*
     93 		 * If the node is an interrupt-controller, we are done. Note that
     94 		 * a node cannot be an interrupt-controller for itself, so we skip
     95 		 * the leaf node here.
     96 		 */
     97 		if (phandle != iparent && of_hasprop(iparent, "interrupt-controller"))
     98 			return iparent;
     99 
    100 		/*
    101 		 * If the node has an explicit interrupt-parent, follow the reference.
    102 		 */
    103 		if (of_hasprop(iparent, "interrupt-parent"))
    104 			return fdtbus_get_phandle(iparent, "interrupt-parent");
    105 
    106 		/*
    107 		 * If the node has an interrupt-map, use it. The caller is responsible
    108 		 * for parsing the interrupt-map and finding the real interrupt parent.
    109 		 */
    110 		if (phandle != iparent && of_hasprop(iparent, "interrupt-map"))
    111 			return iparent;
    112 
    113 		/*
    114 		 * Continue searching up the tree.
    115 		 */
    116 		iparent = OF_parent(iparent);
    117 	} while (iparent > 0);
    118 
    119 	return 0;
    120 }
    121 
    122 static struct fdtbus_interrupt_controller *
    123 fdtbus_get_interrupt_controller(int phandle)
    124 {
    125 	struct fdtbus_interrupt_controller * ic;
    126 	LIST_FOREACH(ic, &fdtbus_interrupt_controllers, ic_next) {
    127 		if (ic->ic_phandle == phandle)
    128 			return ic;
    129 	}
    130 	return NULL;
    131 }
    132 
    133 int
    134 fdtbus_register_interrupt_controller(device_t dev, int phandle,
    135     const struct fdtbus_interrupt_controller_func *funcs)
    136 {
    137 	struct fdtbus_interrupt_controller *ic;
    138 
    139 	ic = kmem_alloc(sizeof(*ic), KM_SLEEP);
    140 	ic->ic_dev = dev;
    141 	ic->ic_phandle = phandle;
    142 	ic->ic_funcs = funcs;
    143 
    144 	LIST_INSERT_HEAD(&fdtbus_interrupt_controllers, ic, ic_next);
    145 
    146 	return 0;
    147 }
    148 
    149 static struct fdtbus_interrupt_cookie *
    150 fdtbus_get_interrupt_cookie(void *cookie)
    151 {
    152 	struct fdtbus_interrupt_cookie *c;
    153 
    154 	mutex_enter(&fdtbus_interrupt_cookie_mutex);
    155 	LIST_FOREACH(c, &fdtbus_interrupt_cookies, c_next) {
    156 		if (c->c_ih == cookie) {
    157 			c->c_refcnt++;
    158 			KASSERT(c->c_refcnt > 0);
    159 			break;
    160 		}
    161 	}
    162 	mutex_exit(&fdtbus_interrupt_cookie_mutex);
    163 	return c;
    164 }
    165 
    166 static void
    167 fdtbus_put_interrupt_cookie(struct fdtbus_interrupt_cookie *c)
    168 {
    169 
    170 	mutex_enter(&fdtbus_interrupt_cookie_mutex);
    171 	KASSERT(c->c_refcnt > 0);
    172 	c->c_refcnt--;
    173 	if (fdtbus_interrupt_cookies_wanted) {
    174 		fdtbus_interrupt_cookies_wanted = false;
    175 		cv_signal(&fdtbus_interrupt_cookie_wait);
    176 	}
    177 	mutex_exit(&fdtbus_interrupt_cookie_mutex);
    178 }
    179 
    180 void *
    181 fdtbus_intr_establish(int phandle, u_int index, int ipl, int flags,
    182     int (*func)(void *), void *arg)
    183 {
    184 	return fdtbus_intr_establish_xname(phandle, index, ipl, flags,
    185 	    func, arg, NULL);
    186 }
    187 
    188 void *
    189 fdtbus_intr_establish_xname(int phandle, u_int index, int ipl, int flags,
    190     int (*func)(void *), void *arg, const char *xname)
    191 {
    192 	const u_int *specifier;
    193 	int ihandle;
    194 
    195 	specifier = get_specifier_by_index(phandle, index, &ihandle);
    196 	if (specifier == NULL)
    197 		return NULL;
    198 
    199 	return fdtbus_intr_establish_raw(ihandle, specifier, ipl,
    200 	    flags, func, arg, xname);
    201 }
    202 
    203 void *
    204 fdtbus_intr_establish_byname(int phandle, const char *name, int ipl,
    205     int flags, int (*func)(void *), void *arg, const char *xname)
    206 {
    207 	u_int index;
    208 	int err;
    209 
    210 	err = fdtbus_get_index(phandle, "interrupt-names", name, &index);
    211 	if (err != 0)
    212 		return NULL;
    213 
    214 	return fdtbus_intr_establish_xname(phandle, index, ipl, flags, func,
    215 	    arg, xname);
    216 }
    217 
    218 void *
    219 fdtbus_intr_establish_raw(int ihandle, const u_int *specifier, int ipl,
    220     int flags, int (*func)(void *), void *arg, const char *xname)
    221 {
    222 	struct fdtbus_interrupt_controller *ic;
    223 	struct fdtbus_interrupt_cookie *c;
    224 	void *ih;
    225 
    226 	ic = fdtbus_get_interrupt_controller(ihandle);
    227 	if (ic == NULL) {
    228 		printf("%s: ihandle %d is not a controller\n",__func__,ihandle);
    229 		return NULL;
    230 	}
    231 
    232 	c = kmem_zalloc(sizeof(*c), KM_SLEEP);
    233 	c->c_ic = ic;
    234 	mutex_enter(&fdtbus_interrupt_cookie_mutex);
    235 	LIST_INSERT_HEAD(&fdtbus_interrupt_cookies, c, c_next);
    236 	mutex_exit(&fdtbus_interrupt_cookie_mutex);
    237 
    238 	/*
    239 	 * XXX This leaves a small window where the handler is registered
    240 	 * (and thus could be called) before the cookie on the list has a
    241 	 * valid lookup key (and thus can be found).  This will cause a
    242 	 * panic in fdt_intr_mask() if that is called from the handler before
    243 	 * this situation is resolved.  For now we just cross our fingers
    244 	 * and hope that the device won't actually interrupt until we return.
    245 	 */
    246 	ih = ic->ic_funcs->establish(ic->ic_dev, __UNCONST(specifier),
    247 	    ipl, flags, func, arg, xname);
    248 	if (ih != NULL) {
    249 		atomic_store_release(&c->c_ih, ih);
    250 	} else {
    251 		mutex_enter(&fdtbus_interrupt_cookie_mutex);
    252 		LIST_REMOVE(c, c_next);
    253 		mutex_exit(&fdtbus_interrupt_cookie_mutex);
    254 		kmem_free(c, sizeof(*c));
    255 	}
    256 
    257 	return ih;
    258 }
    259 
    260 void
    261 fdtbus_intr_disestablish(int phandle, void *cookie)
    262 {
    263 	struct fdtbus_interrupt_cookie *c;
    264 
    265 	if ((c = fdtbus_get_interrupt_cookie(cookie)) == NULL) {
    266 		panic("%s: interrupt handle not valid", __func__);
    267 	}
    268 
    269 	const struct fdtbus_interrupt_controller *ic = c->c_ic;
    270 	ic->ic_funcs->disestablish(ic->ic_dev, cookie);
    271 
    272 	/*
    273 	 * Wait for any dangling references other than ours to
    274 	 * drain away.
    275 	 */
    276 	mutex_enter(&fdtbus_interrupt_cookie_mutex);
    277 	while (c->c_refcnt != 1) {
    278 		KASSERT(c->c_refcnt > 0);
    279 		fdtbus_interrupt_cookies_wanted = true;
    280 		cv_wait(&fdtbus_interrupt_cookie_wait,
    281 			&fdtbus_interrupt_cookie_mutex);
    282 	}
    283 	LIST_REMOVE(c, c_next);
    284 	mutex_exit(&fdtbus_interrupt_cookie_mutex);
    285 
    286 	kmem_free(c, sizeof(*c));
    287 }
    288 
    289 void
    290 fdtbus_intr_mask(int phandle, void *cookie)
    291 {
    292 	struct fdtbus_interrupt_cookie *c;
    293 
    294 	if ((c = fdtbus_get_interrupt_cookie(cookie)) == NULL) {
    295 		panic("%s: interrupt handle not valid", __func__);
    296 	}
    297 
    298 	struct fdtbus_interrupt_controller * const ic = c->c_ic;
    299 
    300 	if (ic->ic_funcs->mask == NULL) {
    301 		panic("%s: no 'mask' method for %s", __func__,
    302 		    device_xname(ic->ic_dev));
    303 	}
    304 
    305 	ic->ic_funcs->mask(ic->ic_dev, cookie);
    306 	fdtbus_put_interrupt_cookie(c);
    307 }
    308 
    309 void
    310 fdtbus_intr_unmask(int phandle, void *cookie)
    311 {
    312 	struct fdtbus_interrupt_cookie *c;
    313 
    314 	if ((c = fdtbus_get_interrupt_cookie(cookie)) == NULL) {
    315 		panic("%s: interrupt handle not valid", __func__);
    316 	}
    317 
    318 	struct fdtbus_interrupt_controller * const ic = c->c_ic;
    319 
    320 	if (ic->ic_funcs->unmask == NULL) {
    321 		panic("%s: no 'unmask' method for %s", __func__,
    322 		    device_xname(ic->ic_dev));
    323 	}
    324 
    325 	ic->ic_funcs->unmask(ic->ic_dev, cookie);
    326 	fdtbus_put_interrupt_cookie(c);
    327 }
    328 
    329 bool
    330 fdtbus_intr_str(int phandle, u_int index, char *buf, size_t buflen)
    331 {
    332 	const u_int *specifier;
    333 	int ihandle;
    334 
    335 	specifier = get_specifier_by_index(phandle, index, &ihandle);
    336 	if (specifier == NULL)
    337 		return false;
    338 
    339 	return fdtbus_intr_str_raw(ihandle, specifier, buf, buflen);
    340 }
    341 
    342 bool
    343 fdtbus_intr_str_raw(int ihandle, const u_int *specifier, char *buf, size_t buflen)
    344 {
    345 	struct fdtbus_interrupt_controller *ic;
    346 
    347 	ic = fdtbus_get_interrupt_controller(ihandle);
    348 	if (ic == NULL)
    349 		return false;
    350 
    351 	return ic->ic_funcs->intrstr(ic->ic_dev, __UNCONST(specifier), buf, buflen);
    352 }
    353 
    354 static int
    355 find_address_cells(int phandle)
    356 {
    357 	uint32_t cells;
    358 
    359 	if (of_getprop_uint32(phandle, "#address-cells", &cells) != 0)
    360 		cells = 2;
    361 
    362 	return cells;
    363 }
    364 
    365 static int
    366 find_interrupt_cells(int phandle)
    367 {
    368 	uint32_t cells;
    369 
    370 	while (phandle > 0) {
    371 		if (of_getprop_uint32(phandle, "#interrupt-cells", &cells) == 0)
    372 			return cells;
    373 		phandle = OF_parent(phandle);
    374 	}
    375 	return 0;
    376 }
    377 
    378 static const u_int *
    379 get_specifier_from_map(int phandle, const u_int *interrupt_spec, int *piphandle)
    380 {
    381 	const u_int *result = NULL;
    382 	int len, resid;
    383 
    384 	const u_int *data = fdtbus_get_prop(phandle, "interrupt-map", &len);
    385 	if (data == NULL || len <= 0)
    386 		return NULL;
    387 	resid = len;
    388 
    389 	/* child unit address: #address-cells prop of child bus node */
    390 	const int cua_cells = find_address_cells(phandle);
    391 	/* child interrupt specifier: #interrupt-cells of the nexus node */
    392 	const int cis_cells = find_interrupt_cells(phandle);
    393 
    394 	/* Offset (in cells) from map entry to child unit address specifier */
    395 	const u_int cua_off = 0;
    396 	/* Offset (in cells) from map entry to child interrupt specifier */
    397 	const u_int cis_off = cua_off + cua_cells;
    398 	/* Offset (in cells) from map entry to interrupt parent phandle */
    399 	const u_int ip_off = cis_off + cis_cells;
    400 	/* Offset (in cells) from map entry to parent unit specifier */
    401 	const u_int pus_off = ip_off + 1;
    402 
    403 	const u_int *p = (const u_int *)data;
    404 	while (resid > 0) {
    405 		/* Interrupt parent phandle */
    406 		const u_int iparent = fdtbus_get_phandle_from_native(be32toh(p[ip_off]));
    407 
    408 		/* parent unit specifier: #address-cells of the interrupt parent */
    409 		const u_int pus_cells = find_address_cells(iparent);
    410 		/* parent interrupt specifier: #interrupt-cells of the interrupt parent */
    411 		const u_int pis_cells = find_interrupt_cells(iparent);
    412 
    413 		/* Offset (in cells) from map entry to parent interrupt specifier */
    414 		const u_int pis_off = pus_off + pus_cells;
    415 
    416 #ifdef FDT_INTR_DEBUG
    417 		printf(" intr map (len %d):", pis_off + pis_cells);
    418 		for (int i = 0; i < pis_off + pis_cells; i++)
    419 			printf(" %08x", p[i]);
    420 		printf("\n");
    421 #endif
    422 
    423 		if (memcmp(&p[cis_off], interrupt_spec, cis_cells * 4) == 0) {
    424 #ifdef FDT_INTR_DEBUG
    425 			const int slen = pus_cells + pis_cells;
    426 			printf(" intr map match iparent %08x slen %d:", iparent, slen);
    427 			for (int i = 0; i < slen; i++)
    428 				printf(" %08x", p[pus_off + i]);
    429 			printf("\n");
    430 #endif
    431 			result = &p[pus_off];
    432 			*piphandle = iparent;
    433 			goto done;
    434 		}
    435 		/* Determine the length of the entry and skip that many
    436 		 * 32 bit words
    437 		 */
    438 		const u_int reclen = pis_off + pis_cells;
    439 		resid -= reclen * sizeof(u_int);
    440 		p += reclen;
    441 	}
    442 
    443 done:
    444 	return result;
    445 }
    446 
    447 
    448 static const u_int *
    449 get_specifier_from_extended(int phandle, int pindex, int *piphandle)
    450 {
    451 	const u_int *result = NULL;
    452 	struct fdt_phandle_data data;
    453 
    454 	if (fdtbus_get_phandle_with_data(phandle, "interrupts-extended",
    455 		"#interrupt-cells", pindex, &data) == 0) {
    456 		*piphandle = data.phandle;
    457 		result = data.values;
    458 	}
    459 
    460 	return result;
    461 }
    462 
    463 static const u_int *
    464 get_specifier_by_index(int phandle, int pindex, int *piphandle)
    465 {
    466 	const u_int *node_specifier;
    467 	int interrupt_parent, interrupt_cells, len;
    468 
    469 	if (of_hasprop(phandle, "interrupts-extended"))
    470 		return get_specifier_from_extended(phandle, pindex, piphandle);
    471 
    472 	interrupt_parent = fdtbus_get_interrupt_parent(phandle);
    473 	if (interrupt_parent <= 0)
    474 		return NULL;
    475 
    476 	node_specifier = fdtbus_get_prop(phandle, "interrupts", &len);
    477 	if (node_specifier == NULL)
    478 		return NULL;
    479 
    480 	interrupt_cells = find_interrupt_cells(interrupt_parent);
    481 	if (interrupt_cells <= 0)
    482 		return NULL;
    483 
    484 	const u_int spec_length = len / 4;
    485 	const u_int nintr = spec_length / interrupt_cells;
    486 	if (pindex >= nintr)
    487 		return NULL;
    488 
    489 	node_specifier += (interrupt_cells * pindex);
    490 
    491 	if (of_hasprop(interrupt_parent, "interrupt-map"))
    492 		return get_specifier_from_map(interrupt_parent, node_specifier, piphandle);
    493 
    494 	*piphandle = interrupt_parent;
    495 
    496 	return node_specifier;
    497 }
    498