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fdt_intr.c revision 1.25
      1 /* $NetBSD: fdt_intr.c,v 1.25 2020/02/16 20:28:18 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 1.25 2020/02/16 20:28:18 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_SPIN, 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 	const u_int *specifier;
    185 	int ihandle;
    186 
    187 	specifier = get_specifier_by_index(phandle, index, &ihandle);
    188 	if (specifier == NULL)
    189 		return NULL;
    190 
    191 	return fdtbus_intr_establish_raw(ihandle, specifier, ipl,
    192 	    flags, func, arg);
    193 }
    194 
    195 void *
    196 fdtbus_intr_establish_byname(int phandle, const char *name, int ipl,
    197     int flags, int (*func)(void *), void *arg)
    198 {
    199 	u_int index;
    200 	int err;
    201 
    202 	err = fdtbus_get_index(phandle, "interrupt-names", name, &index);
    203 	if (err != 0)
    204 		return NULL;
    205 
    206 	return fdtbus_intr_establish(phandle, index, ipl, flags, func, arg);
    207 }
    208 
    209 void *
    210 fdtbus_intr_establish_raw(int ihandle, const u_int *specifier, int ipl,
    211     int flags, int (*func)(void *), void *arg)
    212 {
    213 	struct fdtbus_interrupt_controller *ic;
    214 	struct fdtbus_interrupt_cookie *c;
    215 	void *ih;
    216 
    217 	ic = fdtbus_get_interrupt_controller(ihandle);
    218 	if (ic == NULL) {
    219 		printf("%s: ihandle %d is not a controller\n",__func__,ihandle);
    220 		return NULL;
    221 	}
    222 
    223 	c = kmem_zalloc(sizeof(*c), KM_SLEEP);
    224 	c->c_ic = ic;
    225 	mutex_enter(&fdtbus_interrupt_cookie_mutex);
    226 	LIST_INSERT_HEAD(&fdtbus_interrupt_cookies, c, c_next);
    227 	mutex_exit(&fdtbus_interrupt_cookie_mutex);
    228 
    229 	/*
    230 	 * XXX This leaves a small window where the handler is registered
    231 	 * (and thus could be called) before the cookie on the list has a
    232 	 * valid lookup key (and thus can be found).  This will cause a
    233 	 * panic in fdt_intr_mask() if that is called from the handler before
    234 	 * this situation is resolved.  For now we just cross our fingers
    235 	 * and hope that the device won't actually interrupt until we return.
    236 	 */
    237 	ih = ic->ic_funcs->establish(ic->ic_dev, __UNCONST(specifier),
    238 	    ipl, flags, func, arg);
    239 	if (ih != NULL) {
    240 		atomic_store_release(&c->c_ih, ih);
    241 	} else {
    242 		mutex_enter(&fdtbus_interrupt_cookie_mutex);
    243 		LIST_REMOVE(c, c_next);
    244 		mutex_exit(&fdtbus_interrupt_cookie_mutex);
    245 		kmem_free(c, sizeof(*c));
    246 	}
    247 
    248 	return ih;
    249 }
    250 
    251 void
    252 fdtbus_intr_disestablish(int phandle, void *cookie)
    253 {
    254 	struct fdtbus_interrupt_cookie *c;
    255 
    256 	if ((c = fdtbus_get_interrupt_cookie(cookie)) == NULL) {
    257 		panic("%s: interrupt handle not valid", __func__);
    258 	}
    259 
    260 	const struct fdtbus_interrupt_controller *ic = c->c_ic;
    261 	ic->ic_funcs->disestablish(ic->ic_dev, cookie);
    262 
    263 	/*
    264 	 * Wait for any dangling references other than ours to
    265 	 * drain away.
    266 	 */
    267 	mutex_enter(&fdtbus_interrupt_cookie_mutex);
    268 	while (c->c_refcnt != 1) {
    269 		KASSERT(c->c_refcnt > 0);
    270 		fdtbus_interrupt_cookies_wanted = true;
    271 		cv_wait(&fdtbus_interrupt_cookie_wait,
    272 			&fdtbus_interrupt_cookie_mutex);
    273 	}
    274 	LIST_REMOVE(c, c_next);
    275 	mutex_exit(&fdtbus_interrupt_cookie_mutex);
    276 
    277 	kmem_free(c, sizeof(*c));
    278 }
    279 
    280 void
    281 fdtbus_intr_mask(int phandle, void *cookie)
    282 {
    283 	struct fdtbus_interrupt_cookie *c;
    284 
    285 	if ((c = fdtbus_get_interrupt_cookie(cookie)) == NULL) {
    286 		panic("%s: interrupt handle not valid", __func__);
    287 	}
    288 
    289 	struct fdtbus_interrupt_controller * const ic = c->c_ic;
    290 
    291 	if (ic->ic_funcs->mask == NULL) {
    292 		panic("%s: no 'mask' method for %s", __func__,
    293 		    device_xname(ic->ic_dev));
    294 	}
    295 
    296 	ic->ic_funcs->mask(ic->ic_dev, cookie);
    297 	fdtbus_put_interrupt_cookie(c);
    298 }
    299 
    300 void
    301 fdtbus_intr_unmask(int phandle, void *cookie)
    302 {
    303 	struct fdtbus_interrupt_cookie *c;
    304 
    305 	if ((c = fdtbus_get_interrupt_cookie(cookie)) == NULL) {
    306 		panic("%s: interrupt handle not valid", __func__);
    307 	}
    308 
    309 	struct fdtbus_interrupt_controller * const ic = c->c_ic;
    310 
    311 	if (ic->ic_funcs->unmask == NULL) {
    312 		panic("%s: no 'unmask' method for %s", __func__,
    313 		    device_xname(ic->ic_dev));
    314 	}
    315 
    316 	ic->ic_funcs->unmask(ic->ic_dev, cookie);
    317 	fdtbus_put_interrupt_cookie(c);
    318 }
    319 
    320 bool
    321 fdtbus_intr_str(int phandle, u_int index, char *buf, size_t buflen)
    322 {
    323 	const u_int *specifier;
    324 	int ihandle;
    325 
    326 	specifier = get_specifier_by_index(phandle, index, &ihandle);
    327 	if (specifier == NULL)
    328 		return false;
    329 
    330 	return fdtbus_intr_str_raw(ihandle, specifier, buf, buflen);
    331 }
    332 
    333 bool
    334 fdtbus_intr_str_raw(int ihandle, const u_int *specifier, char *buf, size_t buflen)
    335 {
    336 	struct fdtbus_interrupt_controller *ic;
    337 
    338 	ic = fdtbus_get_interrupt_controller(ihandle);
    339 	if (ic == NULL)
    340 		return false;
    341 
    342 	return ic->ic_funcs->intrstr(ic->ic_dev, __UNCONST(specifier), buf, buflen);
    343 }
    344 
    345 static int
    346 find_address_cells(int phandle)
    347 {
    348 	uint32_t cells;
    349 
    350 	if (of_getprop_uint32(phandle, "#address-cells", &cells) != 0)
    351 		cells = 2;
    352 
    353 	return cells;
    354 }
    355 
    356 static int
    357 find_interrupt_cells(int phandle)
    358 {
    359 	uint32_t cells;
    360 
    361 	while (phandle > 0) {
    362 		if (of_getprop_uint32(phandle, "#interrupt-cells", &cells) == 0)
    363 			return cells;
    364 		phandle = OF_parent(phandle);
    365 	}
    366 	return 0;
    367 }
    368 
    369 static const u_int *
    370 get_specifier_from_map(int phandle, const u_int *interrupt_spec, int *piphandle)
    371 {
    372 	const u_int *result = NULL;
    373 	int len, resid;
    374 
    375 	const u_int *data = fdtbus_get_prop(phandle, "interrupt-map", &len);
    376 	if (data == NULL || len <= 0)
    377 		return NULL;
    378 	resid = len;
    379 
    380 	/* child unit address: #address-cells prop of child bus node */
    381 	const int cua_cells = find_address_cells(phandle);
    382 	/* child interrupt specifier: #interrupt-cells of the nexus node */
    383 	const int cis_cells = find_interrupt_cells(phandle);
    384 
    385 	/* Offset (in cells) from map entry to child unit address specifier */
    386 	const u_int cua_off = 0;
    387 	/* Offset (in cells) from map entry to child interrupt specifier */
    388 	const u_int cis_off = cua_off + cua_cells;
    389 	/* Offset (in cells) from map entry to interrupt parent phandle */
    390 	const u_int ip_off = cis_off + cis_cells;
    391 	/* Offset (in cells) from map entry to parent unit specifier */
    392 	const u_int pus_off = ip_off + 1;
    393 
    394 	const u_int *p = (const u_int *)data;
    395 	while (resid > 0) {
    396 		/* Interrupt parent phandle */
    397 		const u_int iparent = fdtbus_get_phandle_from_native(be32toh(p[ip_off]));
    398 
    399 		/* parent unit specifier: #address-cells of the interrupt parent */
    400 		const u_int pus_cells = find_address_cells(iparent);
    401 		/* parent interrupt specifier: #interrupt-cells of the interrupt parent */
    402 		const u_int pis_cells = find_interrupt_cells(iparent);
    403 
    404 		/* Offset (in cells) from map entry to parent interrupt specifier */
    405 		const u_int pis_off = pus_off + pus_cells;
    406 
    407 #ifdef FDT_INTR_DEBUG
    408 		printf(" intr map (len %d):", pis_off + pis_cells);
    409 		for (int i = 0; i < pis_off + pis_cells; i++)
    410 			printf(" %08x", p[i]);
    411 		printf("\n");
    412 #endif
    413 
    414 		if (memcmp(&p[cis_off], interrupt_spec, cis_cells * 4) == 0) {
    415 #ifdef FDT_INTR_DEBUG
    416 			const int slen = pus_cells + pis_cells;
    417 			printf(" intr map match iparent %08x slen %d:", iparent, slen);
    418 			for (int i = 0; i < slen; i++)
    419 				printf(" %08x", p[pus_off + i]);
    420 			printf("\n");
    421 #endif
    422 			result = &p[pus_off];
    423 			*piphandle = iparent;
    424 			goto done;
    425 		}
    426 		/* Determine the length of the entry and skip that many
    427 		 * 32 bit words
    428 		 */
    429 		const u_int reclen = pis_off + pis_cells;
    430 		resid -= reclen * sizeof(u_int);
    431 		p += reclen;
    432 	}
    433 
    434 done:
    435 	return result;
    436 }
    437 
    438 
    439 static const u_int *
    440 get_specifier_from_extended(int phandle, int pindex, int *piphandle)
    441 {
    442 	const u_int *result = NULL;
    443 	struct fdt_phandle_data data;
    444 
    445 	if (fdtbus_get_phandle_with_data(phandle, "interrupts-extended",
    446 		"#interrupt-cells", pindex, &data) == 0) {
    447 		*piphandle = data.phandle;
    448 		result = data.values;
    449 	}
    450 
    451 	return result;
    452 }
    453 
    454 static const u_int *
    455 get_specifier_by_index(int phandle, int pindex, int *piphandle)
    456 {
    457 	const u_int *node_specifier;
    458 	int interrupt_parent, interrupt_cells, len;
    459 
    460 	if (of_hasprop(phandle, "interrupts-extended"))
    461 		return get_specifier_from_extended(phandle, pindex, piphandle);
    462 
    463 	interrupt_parent = fdtbus_get_interrupt_parent(phandle);
    464 	if (interrupt_parent <= 0)
    465 		return NULL;
    466 
    467 	node_specifier = fdtbus_get_prop(phandle, "interrupts", &len);
    468 	if (node_specifier == NULL)
    469 		return NULL;
    470 
    471 	interrupt_cells = find_interrupt_cells(interrupt_parent);
    472 	if (interrupt_cells <= 0)
    473 		return NULL;
    474 
    475 	const u_int spec_length = len / 4;
    476 	const u_int nintr = spec_length / interrupt_cells;
    477 	if (pindex >= nintr)
    478 		return NULL;
    479 
    480 	node_specifier += (interrupt_cells * pindex);
    481 
    482 	if (of_hasprop(interrupt_parent, "interrupt-map"))
    483 		return get_specifier_from_map(interrupt_parent, node_specifier, piphandle);
    484 
    485 	*piphandle = interrupt_parent;
    486 
    487 	return node_specifier;
    488 }
    489