1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * ARC ARConnect (MultiCore IP) support (formerly known as MCIP)
4 *
5 * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
6 */
7
8 #include <linux/smp.h>
9 #include <linux/irq.h>
10 #include <linux/irqchip/chained_irq.h>
11 #include <linux/spinlock.h>
12 #include <soc/arc/mcip.h>
13 #include <asm/irqflags-arcv2.h>
14 #include <asm/setup.h>
15
16 static DEFINE_RAW_SPINLOCK(mcip_lock);
17
18 #ifdef CONFIG_SMP
19
20 static char smp_cpuinfo_buf[128];
21
22 /*
23 * Set mask to halt GFRC if any online core in SMP cluster is halted.
24 * Only works for ARC HS v3.0+, on earlier versions has no effect.
25 */
26 static void mcip_update_gfrc_halt_mask(int cpu)
27 {
28 struct bcr_generic gfrc;
29 unsigned long flags;
30 u32 gfrc_halt_mask;
31
32 READ_BCR(ARC_REG_GFRC_BUILD, gfrc);
33
34 /*
35 * CMD_GFRC_SET_CORE and CMD_GFRC_READ_CORE commands were added in
36 * GFRC 0x3 version.
37 */
38 if (gfrc.ver < 0x3)
39 return;
40
41 raw_spin_lock_irqsave(&mcip_lock, flags);
42
43 __mcip_cmd(CMD_GFRC_READ_CORE, 0);
44 gfrc_halt_mask = read_aux_reg(ARC_REG_MCIP_READBACK);
45 gfrc_halt_mask |= BIT(cpu);
46 __mcip_cmd_data(CMD_GFRC_SET_CORE, 0, gfrc_halt_mask);
47
48 raw_spin_unlock_irqrestore(&mcip_lock, flags);
49 }
50
51 static void mcip_update_debug_halt_mask(int cpu)
52 {
53 u32 mcip_mask = 0;
54 unsigned long flags;
55
56 raw_spin_lock_irqsave(&mcip_lock, flags);
57
58 /*
59 * mcip_mask is same for CMD_DEBUG_SET_SELECT and CMD_DEBUG_SET_MASK
60 * commands. So read it once instead of reading both CMD_DEBUG_READ_MASK
61 * and CMD_DEBUG_READ_SELECT.
62 */
63 __mcip_cmd(CMD_DEBUG_READ_SELECT, 0);
64 mcip_mask = read_aux_reg(ARC_REG_MCIP_READBACK);
65
66 mcip_mask |= BIT(cpu);
67
68 __mcip_cmd_data(CMD_DEBUG_SET_SELECT, 0, mcip_mask);
69 /*
70 * Parameter specified halt cause:
71 * STATUS32[H]/actionpoint/breakpoint/self-halt
72 * We choose all of them (0xF).
73 */
74 __mcip_cmd_data(CMD_DEBUG_SET_MASK, 0xF, mcip_mask);
75
76 raw_spin_unlock_irqrestore(&mcip_lock, flags);
77 }
78
79 static void mcip_setup_per_cpu(int cpu)
80 {
81 struct mcip_bcr mp;
82
83 READ_BCR(ARC_REG_MCIP_BCR, mp);
84
85 smp_ipi_irq_setup(cpu, IPI_IRQ);
86 smp_ipi_irq_setup(cpu, SOFTIRQ_IRQ);
87
88 /* Update GFRC halt mask as new CPU came online */
89 if (mp.gfrc)
90 mcip_update_gfrc_halt_mask(cpu);
91
92 /* Update MCIP debug mask as new CPU came online */
93 if (mp.dbg)
94 mcip_update_debug_halt_mask(cpu);
95 }
96
97 static void mcip_ipi_send(int cpu)
98 {
99 unsigned long flags;
100 int ipi_was_pending;
101
102 /* ARConnect can only send IPI to others */
103 if (unlikely(cpu == raw_smp_processor_id())) {
104 arc_softirq_trigger(SOFTIRQ_IRQ);
105 return;
106 }
107
108 raw_spin_lock_irqsave(&mcip_lock, flags);
109
110 /*
111 * If receiver already has a pending interrupt, elide sending this one.
112 * Linux cross core calling works well with concurrent IPIs
113 * coalesced into one
114 * see arch/arc/kernel/smp.c: ipi_send_msg_one()
115 */
116 __mcip_cmd(CMD_INTRPT_READ_STATUS, cpu);
117 ipi_was_pending = read_aux_reg(ARC_REG_MCIP_READBACK);
118 if (!ipi_was_pending)
119 __mcip_cmd(CMD_INTRPT_GENERATE_IRQ, cpu);
120
121 raw_spin_unlock_irqrestore(&mcip_lock, flags);
122 }
123
124 static void mcip_ipi_clear(int irq)
125 {
126 unsigned int cpu, c;
127 unsigned long flags;
128
129 if (unlikely(irq == SOFTIRQ_IRQ)) {
130 arc_softirq_clear(irq);
131 return;
132 }
133
134 raw_spin_lock_irqsave(&mcip_lock, flags);
135
136 /* Who sent the IPI */
137 __mcip_cmd(CMD_INTRPT_CHECK_SOURCE, 0);
138
139 cpu = read_aux_reg(ARC_REG_MCIP_READBACK); /* 1,2,4,8... */
140
141 /*
142 * In rare case, multiple concurrent IPIs sent to same target can
143 * possibly be coalesced by MCIP into 1 asserted IRQ, so @cpus can be
144 * "vectored" (multiple bits sets) as opposed to typical single bit
145 */
146 do {
147 c = __ffs(cpu); /* 0,1,2,3 */
148 __mcip_cmd(CMD_INTRPT_GENERATE_ACK, c);
149 cpu &= ~(1U << c);
150 } while (cpu);
151
152 raw_spin_unlock_irqrestore(&mcip_lock, flags);
153 }
154
155 static void mcip_probe_n_setup(void)
156 {
157 struct mcip_bcr mp;
158
159 READ_BCR(ARC_REG_MCIP_BCR, mp);
160
161 sprintf(smp_cpuinfo_buf,
162 "Extn [SMP]\t: ARConnect (v%d): %d cores with %s%s%s%s\n",
163 mp.ver, mp.num_cores,
164 IS_AVAIL1(mp.ipi, "IPI "),
165 IS_AVAIL1(mp.idu, "IDU "),
166 IS_AVAIL1(mp.dbg, "DEBUG "),
167 IS_AVAIL1(mp.gfrc, "GFRC"));
168 }
169
170 struct plat_smp_ops plat_smp_ops = {
171 .info = smp_cpuinfo_buf,
172 .init_early_smp = mcip_probe_n_setup,
173 .init_per_cpu = mcip_setup_per_cpu,
174 .ipi_send = mcip_ipi_send,
175 .ipi_clear = mcip_ipi_clear,
176 };
177
178 #endif
179
180 /***************************************************************************
181 * ARCv2 Interrupt Distribution Unit (IDU)
182 *
183 * Connects external "COMMON" IRQs to core intc, providing:
184 * -dynamic routing (IRQ affinity)
185 * -load balancing (Round Robin interrupt distribution)
186 * -1:N distribution
187 *
188 * It physically resides in the MCIP hw block
189 */
190
191 #include <linux/irqchip.h>
192 #include <linux/of.h>
193 #include <linux/of_irq.h>
194
195 /*
196 * Set the DEST for @cmn_irq to @cpu_mask (1 bit per core)
197 */
198 static void idu_set_dest(unsigned int cmn_irq, unsigned int cpu_mask)
199 {
200 __mcip_cmd_data(CMD_IDU_SET_DEST, cmn_irq, cpu_mask);
201 }
202
203 static void idu_set_mode(unsigned int cmn_irq, bool set_lvl, unsigned int lvl,
204 bool set_distr, unsigned int distr)
205 {
206 union {
207 unsigned int word;
208 struct {
209 unsigned int distr:2, pad:2, lvl:1, pad2:27;
210 };
211 } data;
212
213 data.word = __mcip_cmd_read(CMD_IDU_READ_MODE, cmn_irq);
214 if (set_distr)
215 data.distr = distr;
216 if (set_lvl)
217 data.lvl = lvl;
218 __mcip_cmd_data(CMD_IDU_SET_MODE, cmn_irq, data.word);
219 }
220
221 static void idu_irq_mask_raw(irq_hw_number_t hwirq)
222 {
223 unsigned long flags;
224
225 raw_spin_lock_irqsave(&mcip_lock, flags);
226 __mcip_cmd_data(CMD_IDU_SET_MASK, hwirq, 1);
227 raw_spin_unlock_irqrestore(&mcip_lock, flags);
228 }
229
230 static void idu_irq_mask(struct irq_data *data)
231 {
232 idu_irq_mask_raw(data->hwirq);
233 }
234
235 static void idu_irq_unmask(struct irq_data *data)
236 {
237 unsigned long flags;
238
239 raw_spin_lock_irqsave(&mcip_lock, flags);
240 __mcip_cmd_data(CMD_IDU_SET_MASK, data->hwirq, 0);
241 raw_spin_unlock_irqrestore(&mcip_lock, flags);
242 }
243
244 static void idu_irq_ack(struct irq_data *data)
245 {
246 unsigned long flags;
247
248 raw_spin_lock_irqsave(&mcip_lock, flags);
249 __mcip_cmd(CMD_IDU_ACK_CIRQ, data->hwirq);
250 raw_spin_unlock_irqrestore(&mcip_lock, flags);
251 }
252
253 static void idu_irq_mask_ack(struct irq_data *data)
254 {
255 unsigned long flags;
256
257 raw_spin_lock_irqsave(&mcip_lock, flags);
258 __mcip_cmd_data(CMD_IDU_SET_MASK, data->hwirq, 1);
259 __mcip_cmd(CMD_IDU_ACK_CIRQ, data->hwirq);
260 raw_spin_unlock_irqrestore(&mcip_lock, flags);
261 }
262
263 static int
264 idu_irq_set_affinity(struct irq_data *data, const struct cpumask *cpumask,
265 bool force)
266 {
267 unsigned long flags;
268 cpumask_t online;
269 unsigned int destination_bits;
270 unsigned int distribution_mode;
271
272 /* errout if no online cpu per @cpumask */
273 if (!cpumask_and(&online, cpumask, cpu_online_mask))
274 return -EINVAL;
275
276 raw_spin_lock_irqsave(&mcip_lock, flags);
277
278 destination_bits = cpumask_bits(&online)[0];
279 idu_set_dest(data->hwirq, destination_bits);
280
281 if (ffs(destination_bits) == fls(destination_bits))
282 distribution_mode = IDU_M_DISTRI_DEST;
283 else
284 distribution_mode = IDU_M_DISTRI_RR;
285
286 idu_set_mode(data->hwirq, false, 0, true, distribution_mode);
287
288 raw_spin_unlock_irqrestore(&mcip_lock, flags);
289
290 return IRQ_SET_MASK_OK;
291 }
292
293 static int idu_irq_set_type(struct irq_data *data, u32 type)
294 {
295 unsigned long flags;
296
297 /*
298 * ARCv2 IDU HW does not support inverse polarity, so these are the
299 * only interrupt types supported.
300 */
301 if (type & ~(IRQ_TYPE_EDGE_RISING | IRQ_TYPE_LEVEL_HIGH))
302 return -EINVAL;
303
304 raw_spin_lock_irqsave(&mcip_lock, flags);
305
306 idu_set_mode(data->hwirq, true,
307 type & IRQ_TYPE_EDGE_RISING ? IDU_M_TRIG_EDGE :
308 IDU_M_TRIG_LEVEL,
309 false, 0);
310
311 raw_spin_unlock_irqrestore(&mcip_lock, flags);
312
313 return 0;
314 }
315
316 static void idu_irq_enable(struct irq_data *data)
317 {
318 /*
319 * By default send all common interrupts to all available online CPUs.
320 * The affinity of common interrupts in IDU must be set manually since
321 * in some cases the kernel will not call irq_set_affinity() by itself:
322 * 1. When the kernel is not configured with support of SMP.
323 * 2. When the kernel is configured with support of SMP but upper
324 * interrupt controllers does not support setting of the affinity
325 * and cannot propagate it to IDU.
326 */
327 idu_irq_set_affinity(data, cpu_online_mask, false);
328 idu_irq_unmask(data);
329 }
330
331 static struct irq_chip idu_irq_chip = {
332 .name = "MCIP IDU Intc",
333 .irq_mask = idu_irq_mask,
334 .irq_unmask = idu_irq_unmask,
335 .irq_ack = idu_irq_ack,
336 .irq_mask_ack = idu_irq_mask_ack,
337 .irq_enable = idu_irq_enable,
338 .irq_set_type = idu_irq_set_type,
339 #ifdef CONFIG_SMP
340 .irq_set_affinity = idu_irq_set_affinity,
341 #endif
342
343 };
344
345 static void idu_cascade_isr(struct irq_desc *desc)
346 {
347 struct irq_domain *idu_domain = irq_desc_get_handler_data(desc);
348 struct irq_chip *core_chip = irq_desc_get_chip(desc);
349 irq_hw_number_t core_hwirq = irqd_to_hwirq(irq_desc_get_irq_data(desc));
350 irq_hw_number_t idu_hwirq = core_hwirq - FIRST_EXT_IRQ;
351
352 chained_irq_enter(core_chip, desc);
353 generic_handle_domain_irq(idu_domain, idu_hwirq);
354 chained_irq_exit(core_chip, desc);
355 }
356
357 static int idu_irq_map(struct irq_domain *d, unsigned int virq, irq_hw_number_t hwirq)
358 {
359 irq_set_chip_and_handler(virq, &idu_irq_chip, handle_level_irq);
360 irq_set_status_flags(virq, IRQ_MOVE_PCNTXT);
361
362 return 0;
363 }
364
365 static const struct irq_domain_ops idu_irq_ops = {
366 .xlate = irq_domain_xlate_onetwocell,
367 .map = idu_irq_map,
368 };
369
370 /*
371 * [16, 23]: Statically assigned always private-per-core (Timers, WDT, IPI)
372 * [24, 23+C]: If C > 0 then "C" common IRQs
373 * [24+C, N]: Not statically assigned, private-per-core
374 */
375
376
377 static int __init
378 idu_of_init(struct device_node *intc, struct device_node *parent)
379 {
380 struct irq_domain *domain;
381 int nr_irqs;
382 int i, virq;
383 struct mcip_bcr mp;
384 struct mcip_idu_bcr idu_bcr;
385
386 READ_BCR(ARC_REG_MCIP_BCR, mp);
387
388 if (!mp.idu)
389 panic("IDU not detected, but DeviceTree using it");
390
391 READ_BCR(ARC_REG_MCIP_IDU_BCR, idu_bcr);
392 nr_irqs = mcip_idu_bcr_to_nr_irqs(idu_bcr);
393
394 pr_info("MCIP: IDU supports %u common irqs\n", nr_irqs);
395
396 domain = irq_domain_add_linear(intc, nr_irqs, &idu_irq_ops, NULL);
397
398 /* Parent interrupts (core-intc) are already mapped */
399
400 for (i = 0; i < nr_irqs; i++) {
401 /* Mask all common interrupts by default */
402 idu_irq_mask_raw(i);
403
404 /*
405 * Return parent uplink IRQs (towards core intc) 24,25,.....
406 * this step has been done before already
407 * however we need it to get the parent virq and set IDU handler
408 * as first level isr
409 */
410 virq = irq_create_mapping(NULL, i + FIRST_EXT_IRQ);
411 BUG_ON(!virq);
412 irq_set_chained_handler_and_data(virq, idu_cascade_isr, domain);
413 }
414
415 __mcip_cmd(CMD_IDU_ENABLE, 0);
416
417 return 0;
418 }
419 IRQCHIP_DECLARE(arcv2_idu_intc, "snps,archs-idu-intc", idu_of_init);
420
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