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      1 /*	$NetBSD: intc_fdt.c,v 1.8 2025/02/09 10:08:37 skrll Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2023 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Nick Hudson
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. 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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include "opt_multiprocessor.h"
     33 
     34 #include <sys/cdefs.h>
     35 __KERNEL_RCSID(0, "$NetBSD: intc_fdt.c,v 1.8 2025/02/09 10:08:37 skrll Exp $");
     36 
     37 #include <sys/param.h>
     38 
     39 #include <sys/bus.h>
     40 #include <sys/cpu.h>
     41 #include <sys/device.h>
     42 #include <sys/evcnt.h>
     43 #include <sys/kmem.h>
     44 #include <sys/intr.h>
     45 
     46 #include <dev/fdt/fdtvar.h>
     47 
     48 #include <machine/frame.h>
     49 #include <machine/machdep.h>
     50 #include <machine/sysreg.h>
     51 
     52 static const struct device_compatible_entry compat_data[] = {
     53 	{ .compat = "riscv,cpu-intc" },
     54 	DEVICE_COMPAT_EOL
     55 };
     56 
     57 
     58 struct intc_irqhandler;
     59 struct intc_irq;
     60 
     61 typedef int (*intcih_t)(void *);
     62 
     63 struct intc_irqhandler {
     64 	struct intc_irq		 *ih_irq;
     65 	intcih_t		  ih_fn;
     66 	void			 *ih_arg;
     67 	TAILQ_ENTRY(intc_irqhandler)
     68 				  ih_next;
     69 };
     70 
     71 struct intc_irq {
     72 	struct intc_fdt_softc	*intr_sc;
     73 	void			*intr_ih;
     74 	void			*intr_arg;
     75 	int			 intr_refcnt;
     76 	int			 intr_ipl;
     77 	int			 intr_source;
     78 	int			 intr_istflags;
     79 	struct evcnt *pcpu_evs;
     80 	TAILQ_HEAD(, intc_irqhandler)
     81 				 intr_handlers;
     82 };
     83 
     84 
     85 struct intc_fdt_softc {
     86 	device_t		 sc_dev;
     87 	bus_space_tag_t		 sc_bst;
     88 	bus_space_handle_t	 sc_bsh;
     89 
     90 	struct intc_irq		*sc_irq[IRQ_NSOURCES];
     91 
     92 	struct evcnt		 sc_evs[IRQ_NSOURCES];
     93 
     94 	struct cpu_info 	*sc_ci;
     95 	cpuid_t			 sc_hartid;
     96 };
     97 
     98 static const char * const intc_sources[IRQ_NSOURCES] = {
     99 	/* Software interrupts */
    100 	"(reserved)",
    101 	"Supervisor software",
    102 	"Virtual Supervisor software",
    103 	"Machine software",
    104 
    105 	/* Timer interrupts */
    106 	"(reserved)",
    107 	"Supervisor timer",
    108 	"Virtual Supervisor timer",
    109 	"Machine timer",
    110 
    111 	/* External interrupts */
    112 	"(reserved)",
    113 	"Supervisor external",
    114 	"Virtual Supervisor external",
    115 	"Machine external",
    116 
    117 	"(reserved)",
    118 	"Supervisor guest external.",
    119 	"(reserved)",
    120 	"(reserved)"
    121 };
    122 
    123 #ifndef MULTIPROCESSOR
    124 struct intc_fdt_softc *intc_sc;
    125 #endif
    126 
    127 
    128 static inline struct intc_fdt_softc *
    129 intc_getsc(struct cpu_info *ci)
    130 {
    131 #ifdef MULTIPROCESSOR
    132 	return ci->ci_intcsoftc;
    133 #else
    134 	return intc_sc;
    135 #endif
    136 }
    137 
    138 static void *
    139 intc_intr_establish(struct intc_fdt_softc *sc, u_int source, u_int ipl,
    140     u_int istflags, int (*func)(void *), void *arg, const char *xname)
    141 {
    142 	if (source > IRQ_NSOURCES)
    143 		return NULL;
    144 
    145 	const device_t dev = sc->sc_dev;
    146 	struct intc_irq *irq = sc->sc_irq[source];
    147 	if (irq == NULL) {
    148 		irq = kmem_alloc(sizeof(*irq), KM_SLEEP);
    149 		irq->intr_sc = sc;
    150 		irq->intr_refcnt = 0;
    151 		irq->intr_arg = arg;
    152 		irq->intr_ipl = ipl;
    153 		irq->intr_istflags = istflags;
    154 		irq->intr_source = source;
    155 		TAILQ_INIT(&irq->intr_handlers);
    156 		sc->sc_irq[source] = irq;
    157 
    158 		evcnt_attach_dynamic(&sc->sc_evs[source], EVCNT_TYPE_INTR, NULL,
    159 		    device_xname(sc->sc_dev), intc_sources[source]);
    160 	} else {
    161 		if (irq->intr_arg == NULL || arg == NULL) {
    162 			device_printf(dev,
    163 			    "cannot share irq with NULL-arg handler\n");
    164 			return NULL;
    165 		}
    166 		if (irq->intr_ipl != ipl) {
    167 			device_printf(dev,
    168 			    "cannot share irq with different ipl\n");
    169 			return NULL;
    170 		}
    171 		if (irq->intr_istflags != istflags) {
    172 			device_printf(dev,
    173 			    "cannot share irq between mpsafe/non-mpsafe\n");
    174 			return NULL;
    175 		}
    176 	}
    177 
    178 	struct intc_irqhandler *irqh = kmem_alloc(sizeof(*irqh), KM_SLEEP);
    179 	irqh->ih_irq = irq;
    180 	irqh->ih_fn = func;
    181 	irqh->ih_arg = arg;
    182 
    183 	irq->intr_refcnt++;
    184 	TAILQ_INSERT_TAIL(&irq->intr_handlers, irqh, ih_next);
    185 
    186 	/*
    187 	 * XXX interrupt_distribute(9) assumes that any interrupt
    188 	 * handle can be used as an input to the MD interrupt_distribute
    189 	 * implementation, so we are forced to return the handle
    190 	 * we got back from intr_establish().  Upshot is that the
    191 	 * input to bcm2835_icu_fdt_disestablish() is ambiguous for
    192 	 * shared IRQs, rendering them un-disestablishable.
    193 	 */
    194 
    195 	return irqh;
    196 }
    197 
    198 
    199 static void *
    200 intc_fdt_establish(device_t dev, u_int *specifier, int ipl, int flags,
    201     int (*func)(void *), void *arg, const char *xname)
    202 {
    203 	struct intc_fdt_softc * const sc = device_private(dev);
    204 
    205 	/*
    206 	 * 1st (and only) cell is the interrupt source, e.g.
    207 	 *  1  IRQ_SUPERVISOR_SOFTWARE
    208 	 *  5  IRQ_SUPERVISOR_TIMER
    209 	 *  9  IRQ_SUPERVISOR_EXTERNAL
    210 	 */
    211 
    212 	const u_int source = be32toh(specifier[0]);
    213 	const u_int mpsafe = (flags & FDT_INTR_MPSAFE) ? IST_MPSAFE : 0;
    214 
    215 	return intc_intr_establish(sc, source, ipl, mpsafe, func, arg, xname);
    216 }
    217 
    218 static void
    219 intc_fdt_disestablish(device_t dev, void *ih)
    220 {
    221 #if 0
    222 	struct intc_fdt_softc * const sc = device_private(dev);
    223 #endif
    224 }
    225 
    226 static bool
    227 intc_fdt_intrstr(device_t dev, u_int *specifier, char *buf, size_t buflen)
    228 {
    229 	if (!specifier)
    230 		return false;
    231 
    232 	struct intc_fdt_softc * const sc = device_private(dev);
    233 	if (sc->sc_ci == NULL)
    234 		return false;
    235 
    236 	const u_int source = be32toh(specifier[0]);
    237 	snprintf(buf, buflen, "cpu%u/%s #%u", cpu_index(sc->sc_ci),
    238 	    intc_sources[source], source);
    239 
    240 	return true;
    241 }
    242 
    243 
    244 struct fdtbus_interrupt_controller_func intc_fdt_funcs = {
    245 	.establish = intc_fdt_establish,
    246 	.disestablish = intc_fdt_disestablish,
    247 	.intrstr = intc_fdt_intrstr
    248 };
    249 
    250 
    251 static void
    252 intc_intr_handler(struct trapframe *tf, register_t epc, register_t status,
    253     register_t cause)
    254 {
    255 	const int ppl = splhigh();
    256 	struct cpu_info * const ci = curcpu();
    257 	unsigned long pending;
    258 	int ipl;
    259 
    260 	KASSERT(CAUSE_INTERRUPT_P(cause));
    261 
    262 	struct intc_fdt_softc * const sc = intc_getsc(ci);
    263 
    264 	ci->ci_intr_depth++;
    265 	ci->ci_data.cpu_nintr++;
    266 
    267 	while (ppl < (ipl = splintr(&pending))) {
    268 		if (pending == 0)
    269 			continue;
    270 
    271 		splx(ipl);
    272 
    273 		int source = ffs(pending) - 1;
    274 		struct intc_irq *irq = sc->sc_irq[source];
    275 		sc->sc_evs[source].ev_count++;
    276 
    277 		KASSERTMSG(irq != NULL, "source %d\n", source);
    278 
    279 		if (irq) {
    280 			struct intc_irqhandler *iih;
    281 
    282 			bool mpsafe =
    283 			    source != IRQ_SUPERVISOR_EXTERNAL ||
    284 			    (irq->intr_istflags & IST_MPSAFE) != 0;
    285 			struct clockframe cf = {
    286 				.cf_epc = epc,
    287 				.cf_status = status,
    288 				.cf_intr_depth = ci->ci_intr_depth
    289 			};
    290 
    291 			if (!mpsafe) {
    292 				KERNEL_LOCK(1, NULL);
    293 			}
    294 
    295 			TAILQ_FOREACH(iih, &irq->intr_handlers, ih_next) {
    296 				int handled =
    297 				    iih->ih_fn(iih->ih_arg ? iih->ih_arg : &cf);
    298 				if (handled)
    299 					break;
    300 			}
    301 
    302 			if (!mpsafe) {
    303 				KERNEL_UNLOCK_ONE(NULL);
    304 			}
    305 		}
    306 		splhigh();
    307 	}
    308 	ci->ci_intr_depth--;
    309 	splx(ppl);
    310 }
    311 
    312 
    313 
    314 static int
    315 intc_match(device_t parent, cfdata_t cf, void *aux)
    316 {
    317 	struct fdt_attach_args * const faa = aux;
    318 	return of_compatible_match(faa->faa_phandle, compat_data);
    319 }
    320 
    321 static void
    322 intc_attach(device_t parent, device_t self, void *aux)
    323 {
    324 	const struct fdt_attach_args * const faa = aux;
    325 	const int phandle = faa->faa_phandle;
    326 
    327 	int error = fdtbus_register_interrupt_controller(self, phandle,
    328 	    &intc_fdt_funcs);
    329 	if (error) {
    330 		aprint_error(": couldn't register with fdtbus: %d\n", error);
    331 		return;
    332 	}
    333 
    334 	struct cpu_info * const ci = device_private(parent);
    335 	if (ci == NULL) {
    336 		aprint_naive(": disabled\n");
    337 		aprint_normal(": disabled\n");
    338 		return;
    339 	}
    340 	aprint_naive("\n");
    341 	aprint_normal(": local interrupt controller\n");
    342 
    343 	struct intc_fdt_softc * const sc = device_private(self);
    344 
    345 	riscv_intr_set_handler(intc_intr_handler);
    346 
    347 	sc->sc_dev = self;
    348 	sc->sc_ci = ci;
    349 	sc->sc_hartid = ci->ci_cpuid;
    350 
    351 	intc_intr_establish(sc, IRQ_SUPERVISOR_TIMER, IPL_SCHED, IST_MPSAFE,
    352 	    riscv_timer_intr, NULL, "clock");
    353 #ifdef MULTIPROCESSOR
    354 	ci->ci_intcsoftc = sc;
    355 	intc_intr_establish(sc, IRQ_SUPERVISOR_SOFTWARE, IPL_HIGH, IST_MPSAFE,
    356 	    riscv_ipi_intr, NULL, "ipi");
    357 #else
    358 	intc_sc = sc;
    359 #endif
    360 }
    361 
    362 CFATTACH_DECL_NEW(intc_fdt, sizeof(struct intc_fdt_softc),
    363 	intc_match, intc_attach, NULL, NULL);
    364