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1/*
2 * ARC ARConnect (MultiCore IP) support (formerly known as MCIP)
3 *
4 * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/smp.h>
12#include <linux/irq.h>
13#include <linux/irqchip/chained_irq.h>
14#include <linux/spinlock.h>
15#include <soc/arc/mcip.h>
16#include <asm/irqflags-arcv2.h>
17#include <asm/setup.h>
18
19static DEFINE_RAW_SPINLOCK(mcip_lock);
20
21#ifdef CONFIG_SMP
22
23static char smp_cpuinfo_buf[128];
24
25/*
26 * Set mask to halt GFRC if any online core in SMP cluster is halted.
27 * Only works for ARC HS v3.0+, on earlier versions has no effect.
28 */
29static void mcip_update_gfrc_halt_mask(int cpu)
30{
31 struct bcr_generic gfrc;
32 unsigned long flags;
33 u32 gfrc_halt_mask;
34
35 READ_BCR(ARC_REG_GFRC_BUILD, gfrc);
36
37 /*
38 * CMD_GFRC_SET_CORE and CMD_GFRC_READ_CORE commands were added in
39 * GFRC 0x3 version.
40 */
41 if (gfrc.ver < 0x3)
42 return;
43
44 raw_spin_lock_irqsave(&mcip_lock, flags);
45
46 __mcip_cmd(CMD_GFRC_READ_CORE, 0);
47 gfrc_halt_mask = read_aux_reg(ARC_REG_MCIP_READBACK);
48 gfrc_halt_mask |= BIT(cpu);
49 __mcip_cmd_data(CMD_GFRC_SET_CORE, 0, gfrc_halt_mask);
50
51 raw_spin_unlock_irqrestore(&mcip_lock, flags);
52}
53
54static void mcip_update_debug_halt_mask(int cpu)
55{
56 u32 mcip_mask = 0;
57 unsigned long flags;
58
59 raw_spin_lock_irqsave(&mcip_lock, flags);
60
61 /*
62 * mcip_mask is same for CMD_DEBUG_SET_SELECT and CMD_DEBUG_SET_MASK
63 * commands. So read it once instead of reading both CMD_DEBUG_READ_MASK
64 * and CMD_DEBUG_READ_SELECT.
65 */
66 __mcip_cmd(CMD_DEBUG_READ_SELECT, 0);
67 mcip_mask = read_aux_reg(ARC_REG_MCIP_READBACK);
68
69 mcip_mask |= BIT(cpu);
70
71 __mcip_cmd_data(CMD_DEBUG_SET_SELECT, 0, mcip_mask);
72 /*
73 * Parameter specified halt cause:
74 * STATUS32[H]/actionpoint/breakpoint/self-halt
75 * We choose all of them (0xF).
76 */
77 __mcip_cmd_data(CMD_DEBUG_SET_MASK, 0xF, mcip_mask);
78
79 raw_spin_unlock_irqrestore(&mcip_lock, flags);
80}
81
82static void mcip_setup_per_cpu(int cpu)
83{
84 struct mcip_bcr mp;
85
86 READ_BCR(ARC_REG_MCIP_BCR, mp);
87
88 smp_ipi_irq_setup(cpu, IPI_IRQ);
89 smp_ipi_irq_setup(cpu, SOFTIRQ_IRQ);
90
91 /* Update GFRC halt mask as new CPU came online */
92 if (mp.gfrc)
93 mcip_update_gfrc_halt_mask(cpu);
94
95 /* Update MCIP debug mask as new CPU came online */
96 if (mp.dbg)
97 mcip_update_debug_halt_mask(cpu);
98}
99
100static void mcip_ipi_send(int cpu)
101{
102 unsigned long flags;
103 int ipi_was_pending;
104
105 /* ARConnect can only send IPI to others */
106 if (unlikely(cpu == raw_smp_processor_id())) {
107 arc_softirq_trigger(SOFTIRQ_IRQ);
108 return;
109 }
110
111 raw_spin_lock_irqsave(&mcip_lock, flags);
112
113 /*
114 * If receiver already has a pending interrupt, elide sending this one.
115 * Linux cross core calling works well with concurrent IPIs
116 * coalesced into one
117 * see arch/arc/kernel/smp.c: ipi_send_msg_one()
118 */
119 __mcip_cmd(CMD_INTRPT_READ_STATUS, cpu);
120 ipi_was_pending = read_aux_reg(ARC_REG_MCIP_READBACK);
121 if (!ipi_was_pending)
122 __mcip_cmd(CMD_INTRPT_GENERATE_IRQ, cpu);
123
124 raw_spin_unlock_irqrestore(&mcip_lock, flags);
125}
126
127static void mcip_ipi_clear(int irq)
128{
129 unsigned int cpu, c;
130 unsigned long flags;
131
132 if (unlikely(irq == SOFTIRQ_IRQ)) {
133 arc_softirq_clear(irq);
134 return;
135 }
136
137 raw_spin_lock_irqsave(&mcip_lock, flags);
138
139 /* Who sent the IPI */
140 __mcip_cmd(CMD_INTRPT_CHECK_SOURCE, 0);
141
142 cpu = read_aux_reg(ARC_REG_MCIP_READBACK); /* 1,2,4,8... */
143
144 /*
145 * In rare case, multiple concurrent IPIs sent to same target can
146 * possibly be coalesced by MCIP into 1 asserted IRQ, so @cpus can be
147 * "vectored" (multiple bits sets) as opposed to typical single bit
148 */
149 do {
150 c = __ffs(cpu); /* 0,1,2,3 */
151 __mcip_cmd(CMD_INTRPT_GENERATE_ACK, c);
152 cpu &= ~(1U << c);
153 } while (cpu);
154
155 raw_spin_unlock_irqrestore(&mcip_lock, flags);
156}
157
158static void mcip_probe_n_setup(void)
159{
160 struct mcip_bcr mp;
161
162 READ_BCR(ARC_REG_MCIP_BCR, mp);
163
164 sprintf(smp_cpuinfo_buf,
165 "Extn [SMP]\t: ARConnect (v%d): %d cores with %s%s%s%s\n",
166 mp.ver, mp.num_cores,
167 IS_AVAIL1(mp.ipi, "IPI "),
168 IS_AVAIL1(mp.idu, "IDU "),
169 IS_AVAIL1(mp.dbg, "DEBUG "),
170 IS_AVAIL1(mp.gfrc, "GFRC"));
171
172 cpuinfo_arc700[0].extn.gfrc = mp.gfrc;
173}
174
175struct plat_smp_ops plat_smp_ops = {
176 .info = smp_cpuinfo_buf,
177 .init_early_smp = mcip_probe_n_setup,
178 .init_per_cpu = mcip_setup_per_cpu,
179 .ipi_send = mcip_ipi_send,
180 .ipi_clear = mcip_ipi_clear,
181};
182
183#endif
184
185/***************************************************************************
186 * ARCv2 Interrupt Distribution Unit (IDU)
187 *
188 * Connects external "COMMON" IRQs to core intc, providing:
189 * -dynamic routing (IRQ affinity)
190 * -load balancing (Round Robin interrupt distribution)
191 * -1:N distribution
192 *
193 * It physically resides in the MCIP hw block
194 */
195
196#include <linux/irqchip.h>
197#include <linux/of.h>
198#include <linux/of_irq.h>
199
200/*
201 * Set the DEST for @cmn_irq to @cpu_mask (1 bit per core)
202 */
203static void idu_set_dest(unsigned int cmn_irq, unsigned int cpu_mask)
204{
205 __mcip_cmd_data(CMD_IDU_SET_DEST, cmn_irq, cpu_mask);
206}
207
208static void idu_set_mode(unsigned int cmn_irq, unsigned int lvl,
209 unsigned int distr)
210{
211 union {
212 unsigned int word;
213 struct {
214 unsigned int distr:2, pad:2, lvl:1, pad2:27;
215 };
216 } data;
217
218 data.distr = distr;
219 data.lvl = lvl;
220 __mcip_cmd_data(CMD_IDU_SET_MODE, cmn_irq, data.word);
221}
222
223static void idu_irq_mask_raw(irq_hw_number_t hwirq)
224{
225 unsigned long flags;
226
227 raw_spin_lock_irqsave(&mcip_lock, flags);
228 __mcip_cmd_data(CMD_IDU_SET_MASK, hwirq, 1);
229 raw_spin_unlock_irqrestore(&mcip_lock, flags);
230}
231
232static void idu_irq_mask(struct irq_data *data)
233{
234 idu_irq_mask_raw(data->hwirq);
235}
236
237static void idu_irq_unmask(struct irq_data *data)
238{
239 unsigned long flags;
240
241 raw_spin_lock_irqsave(&mcip_lock, flags);
242 __mcip_cmd_data(CMD_IDU_SET_MASK, data->hwirq, 0);
243 raw_spin_unlock_irqrestore(&mcip_lock, flags);
244}
245
246static int
247idu_irq_set_affinity(struct irq_data *data, const struct cpumask *cpumask,
248 bool force)
249{
250 unsigned long flags;
251 cpumask_t online;
252 unsigned int destination_bits;
253 unsigned int distribution_mode;
254
255 /* errout if no online cpu per @cpumask */
256 if (!cpumask_and(&online, cpumask, cpu_online_mask))
257 return -EINVAL;
258
259 raw_spin_lock_irqsave(&mcip_lock, flags);
260
261 destination_bits = cpumask_bits(&online)[0];
262 idu_set_dest(data->hwirq, destination_bits);
263
264 if (ffs(destination_bits) == fls(destination_bits))
265 distribution_mode = IDU_M_DISTRI_DEST;
266 else
267 distribution_mode = IDU_M_DISTRI_RR;
268
269 idu_set_mode(data->hwirq, IDU_M_TRIG_LEVEL, distribution_mode);
270
271 raw_spin_unlock_irqrestore(&mcip_lock, flags);
272
273 return IRQ_SET_MASK_OK;
274}
275
276static void idu_irq_enable(struct irq_data *data)
277{
278 /*
279 * By default send all common interrupts to all available online CPUs.
280 * The affinity of common interrupts in IDU must be set manually since
281 * in some cases the kernel will not call irq_set_affinity() by itself:
282 * 1. When the kernel is not configured with support of SMP.
283 * 2. When the kernel is configured with support of SMP but upper
284 * interrupt controllers does not support setting of the affinity
285 * and cannot propagate it to IDU.
286 */
287 idu_irq_set_affinity(data, cpu_online_mask, false);
288 idu_irq_unmask(data);
289}
290
291static struct irq_chip idu_irq_chip = {
292 .name = "MCIP IDU Intc",
293 .irq_mask = idu_irq_mask,
294 .irq_unmask = idu_irq_unmask,
295 .irq_enable = idu_irq_enable,
296#ifdef CONFIG_SMP
297 .irq_set_affinity = idu_irq_set_affinity,
298#endif
299
300};
301
302static void idu_cascade_isr(struct irq_desc *desc)
303{
304 struct irq_domain *idu_domain = irq_desc_get_handler_data(desc);
305 struct irq_chip *core_chip = irq_desc_get_chip(desc);
306 irq_hw_number_t core_hwirq = irqd_to_hwirq(irq_desc_get_irq_data(desc));
307 irq_hw_number_t idu_hwirq = core_hwirq - FIRST_EXT_IRQ;
308
309 chained_irq_enter(core_chip, desc);
310 generic_handle_irq(irq_find_mapping(idu_domain, idu_hwirq));
311 chained_irq_exit(core_chip, desc);
312}
313
314static int idu_irq_map(struct irq_domain *d, unsigned int virq, irq_hw_number_t hwirq)
315{
316 irq_set_chip_and_handler(virq, &idu_irq_chip, handle_level_irq);
317 irq_set_status_flags(virq, IRQ_MOVE_PCNTXT);
318
319 return 0;
320}
321
322static const struct irq_domain_ops idu_irq_ops = {
323 .xlate = irq_domain_xlate_onecell,
324 .map = idu_irq_map,
325};
326
327/*
328 * [16, 23]: Statically assigned always private-per-core (Timers, WDT, IPI)
329 * [24, 23+C]: If C > 0 then "C" common IRQs
330 * [24+C, N]: Not statically assigned, private-per-core
331 */
332
333
334static int __init
335idu_of_init(struct device_node *intc, struct device_node *parent)
336{
337 struct irq_domain *domain;
338 int nr_irqs;
339 int i, virq;
340 struct mcip_bcr mp;
341 struct mcip_idu_bcr idu_bcr;
342
343 READ_BCR(ARC_REG_MCIP_BCR, mp);
344
345 if (!mp.idu)
346 panic("IDU not detected, but DeviceTree using it");
347
348 READ_BCR(ARC_REG_MCIP_IDU_BCR, idu_bcr);
349 nr_irqs = mcip_idu_bcr_to_nr_irqs(idu_bcr);
350
351 pr_info("MCIP: IDU supports %u common irqs\n", nr_irqs);
352
353 domain = irq_domain_add_linear(intc, nr_irqs, &idu_irq_ops, NULL);
354
355 /* Parent interrupts (core-intc) are already mapped */
356
357 for (i = 0; i < nr_irqs; i++) {
358 /* Mask all common interrupts by default */
359 idu_irq_mask_raw(i);
360
361 /*
362 * Return parent uplink IRQs (towards core intc) 24,25,.....
363 * this step has been done before already
364 * however we need it to get the parent virq and set IDU handler
365 * as first level isr
366 */
367 virq = irq_create_mapping(NULL, i + FIRST_EXT_IRQ);
368 BUG_ON(!virq);
369 irq_set_chained_handler_and_data(virq, idu_cascade_isr, domain);
370 }
371
372 __mcip_cmd(CMD_IDU_ENABLE, 0);
373
374 return 0;
375}
376IRQCHIP_DECLARE(arcv2_idu_intc, "snps,archs-idu-intc", idu_of_init);