Loading...
Note: File does not exist in v3.15.
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
25static void mcip_setup_per_cpu(int cpu)
26{
27 smp_ipi_irq_setup(cpu, IPI_IRQ);
28 smp_ipi_irq_setup(cpu, SOFTIRQ_IRQ);
29}
30
31static void mcip_ipi_send(int cpu)
32{
33 unsigned long flags;
34 int ipi_was_pending;
35
36 /* ARConnect can only send IPI to others */
37 if (unlikely(cpu == raw_smp_processor_id())) {
38 arc_softirq_trigger(SOFTIRQ_IRQ);
39 return;
40 }
41
42 raw_spin_lock_irqsave(&mcip_lock, flags);
43
44 /*
45 * If receiver already has a pending interrupt, elide sending this one.
46 * Linux cross core calling works well with concurrent IPIs
47 * coalesced into one
48 * see arch/arc/kernel/smp.c: ipi_send_msg_one()
49 */
50 __mcip_cmd(CMD_INTRPT_READ_STATUS, cpu);
51 ipi_was_pending = read_aux_reg(ARC_REG_MCIP_READBACK);
52 if (!ipi_was_pending)
53 __mcip_cmd(CMD_INTRPT_GENERATE_IRQ, cpu);
54
55 raw_spin_unlock_irqrestore(&mcip_lock, flags);
56}
57
58static void mcip_ipi_clear(int irq)
59{
60 unsigned int cpu, c;
61 unsigned long flags;
62
63 if (unlikely(irq == SOFTIRQ_IRQ)) {
64 arc_softirq_clear(irq);
65 return;
66 }
67
68 raw_spin_lock_irqsave(&mcip_lock, flags);
69
70 /* Who sent the IPI */
71 __mcip_cmd(CMD_INTRPT_CHECK_SOURCE, 0);
72
73 cpu = read_aux_reg(ARC_REG_MCIP_READBACK); /* 1,2,4,8... */
74
75 /*
76 * In rare case, multiple concurrent IPIs sent to same target can
77 * possibly be coalesced by MCIP into 1 asserted IRQ, so @cpus can be
78 * "vectored" (multiple bits sets) as opposed to typical single bit
79 */
80 do {
81 c = __ffs(cpu); /* 0,1,2,3 */
82 __mcip_cmd(CMD_INTRPT_GENERATE_ACK, c);
83 cpu &= ~(1U << c);
84 } while (cpu);
85
86 raw_spin_unlock_irqrestore(&mcip_lock, flags);
87}
88
89static void mcip_probe_n_setup(void)
90{
91 struct mcip_bcr mp;
92
93 READ_BCR(ARC_REG_MCIP_BCR, mp);
94
95 sprintf(smp_cpuinfo_buf,
96 "Extn [SMP]\t: ARConnect (v%d): %d cores with %s%s%s%s\n",
97 mp.ver, mp.num_cores,
98 IS_AVAIL1(mp.ipi, "IPI "),
99 IS_AVAIL1(mp.idu, "IDU "),
100 IS_AVAIL1(mp.dbg, "DEBUG "),
101 IS_AVAIL1(mp.gfrc, "GFRC"));
102
103 cpuinfo_arc700[0].extn.gfrc = mp.gfrc;
104
105 if (mp.dbg) {
106 __mcip_cmd_data(CMD_DEBUG_SET_SELECT, 0, 0xf);
107 __mcip_cmd_data(CMD_DEBUG_SET_MASK, 0xf, 0xf);
108 }
109}
110
111struct plat_smp_ops plat_smp_ops = {
112 .info = smp_cpuinfo_buf,
113 .init_early_smp = mcip_probe_n_setup,
114 .init_per_cpu = mcip_setup_per_cpu,
115 .ipi_send = mcip_ipi_send,
116 .ipi_clear = mcip_ipi_clear,
117};
118
119#endif
120
121/***************************************************************************
122 * ARCv2 Interrupt Distribution Unit (IDU)
123 *
124 * Connects external "COMMON" IRQs to core intc, providing:
125 * -dynamic routing (IRQ affinity)
126 * -load balancing (Round Robin interrupt distribution)
127 * -1:N distribution
128 *
129 * It physically resides in the MCIP hw block
130 */
131
132#include <linux/irqchip.h>
133#include <linux/of.h>
134#include <linux/of_irq.h>
135
136/*
137 * Set the DEST for @cmn_irq to @cpu_mask (1 bit per core)
138 */
139static void idu_set_dest(unsigned int cmn_irq, unsigned int cpu_mask)
140{
141 __mcip_cmd_data(CMD_IDU_SET_DEST, cmn_irq, cpu_mask);
142}
143
144static void idu_set_mode(unsigned int cmn_irq, unsigned int lvl,
145 unsigned int distr)
146{
147 union {
148 unsigned int word;
149 struct {
150 unsigned int distr:2, pad:2, lvl:1, pad2:27;
151 };
152 } data;
153
154 data.distr = distr;
155 data.lvl = lvl;
156 __mcip_cmd_data(CMD_IDU_SET_MODE, cmn_irq, data.word);
157}
158
159static void idu_irq_mask(struct irq_data *data)
160{
161 unsigned long flags;
162
163 raw_spin_lock_irqsave(&mcip_lock, flags);
164 __mcip_cmd_data(CMD_IDU_SET_MASK, data->hwirq, 1);
165 raw_spin_unlock_irqrestore(&mcip_lock, flags);
166}
167
168static void idu_irq_unmask(struct irq_data *data)
169{
170 unsigned long flags;
171
172 raw_spin_lock_irqsave(&mcip_lock, flags);
173 __mcip_cmd_data(CMD_IDU_SET_MASK, data->hwirq, 0);
174 raw_spin_unlock_irqrestore(&mcip_lock, flags);
175}
176
177static int
178idu_irq_set_affinity(struct irq_data *data, const struct cpumask *cpumask,
179 bool force)
180{
181 unsigned long flags;
182 cpumask_t online;
183 unsigned int destination_bits;
184 unsigned int distribution_mode;
185
186 /* errout if no online cpu per @cpumask */
187 if (!cpumask_and(&online, cpumask, cpu_online_mask))
188 return -EINVAL;
189
190 raw_spin_lock_irqsave(&mcip_lock, flags);
191
192 destination_bits = cpumask_bits(&online)[0];
193 idu_set_dest(data->hwirq, destination_bits);
194
195 if (ffs(destination_bits) == fls(destination_bits))
196 distribution_mode = IDU_M_DISTRI_DEST;
197 else
198 distribution_mode = IDU_M_DISTRI_RR;
199
200 idu_set_mode(data->hwirq, IDU_M_TRIG_LEVEL, distribution_mode);
201
202 raw_spin_unlock_irqrestore(&mcip_lock, flags);
203
204 return IRQ_SET_MASK_OK;
205}
206
207static void idu_irq_enable(struct irq_data *data)
208{
209 /*
210 * By default send all common interrupts to all available online CPUs.
211 * The affinity of common interrupts in IDU must be set manually since
212 * in some cases the kernel will not call irq_set_affinity() by itself:
213 * 1. When the kernel is not configured with support of SMP.
214 * 2. When the kernel is configured with support of SMP but upper
215 * interrupt controllers does not support setting of the affinity
216 * and cannot propagate it to IDU.
217 */
218 idu_irq_set_affinity(data, cpu_online_mask, false);
219 idu_irq_unmask(data);
220}
221
222static struct irq_chip idu_irq_chip = {
223 .name = "MCIP IDU Intc",
224 .irq_mask = idu_irq_mask,
225 .irq_unmask = idu_irq_unmask,
226 .irq_enable = idu_irq_enable,
227#ifdef CONFIG_SMP
228 .irq_set_affinity = idu_irq_set_affinity,
229#endif
230
231};
232
233static irq_hw_number_t idu_first_hwirq;
234
235static void idu_cascade_isr(struct irq_desc *desc)
236{
237 struct irq_domain *idu_domain = irq_desc_get_handler_data(desc);
238 struct irq_chip *core_chip = irq_desc_get_chip(desc);
239 irq_hw_number_t core_hwirq = irqd_to_hwirq(irq_desc_get_irq_data(desc));
240 irq_hw_number_t idu_hwirq = core_hwirq - idu_first_hwirq;
241
242 chained_irq_enter(core_chip, desc);
243 generic_handle_irq(irq_find_mapping(idu_domain, idu_hwirq));
244 chained_irq_exit(core_chip, desc);
245}
246
247static int idu_irq_map(struct irq_domain *d, unsigned int virq, irq_hw_number_t hwirq)
248{
249 irq_set_chip_and_handler(virq, &idu_irq_chip, handle_level_irq);
250 irq_set_status_flags(virq, IRQ_MOVE_PCNTXT);
251
252 return 0;
253}
254
255static int idu_irq_xlate(struct irq_domain *d, struct device_node *n,
256 const u32 *intspec, unsigned int intsize,
257 irq_hw_number_t *out_hwirq, unsigned int *out_type)
258{
259 /*
260 * Ignore value of interrupt distribution mode for common interrupts in
261 * IDU which resides in intspec[1] since setting an affinity using value
262 * from Device Tree is deprecated in ARC.
263 */
264 *out_hwirq = intspec[0];
265 *out_type = IRQ_TYPE_NONE;
266
267 return 0;
268}
269
270static const struct irq_domain_ops idu_irq_ops = {
271 .xlate = idu_irq_xlate,
272 .map = idu_irq_map,
273};
274
275/*
276 * [16, 23]: Statically assigned always private-per-core (Timers, WDT, IPI)
277 * [24, 23+C]: If C > 0 then "C" common IRQs
278 * [24+C, N]: Not statically assigned, private-per-core
279 */
280
281
282static int __init
283idu_of_init(struct device_node *intc, struct device_node *parent)
284{
285 struct irq_domain *domain;
286 /* Read IDU BCR to confirm nr_irqs */
287 int nr_irqs = of_irq_count(intc);
288 int i, virq;
289 struct mcip_bcr mp;
290
291 READ_BCR(ARC_REG_MCIP_BCR, mp);
292
293 if (!mp.idu)
294 panic("IDU not detected, but DeviceTree using it");
295
296 pr_info("MCIP: IDU referenced from Devicetree %d irqs\n", nr_irqs);
297
298 domain = irq_domain_add_linear(intc, nr_irqs, &idu_irq_ops, NULL);
299
300 /* Parent interrupts (core-intc) are already mapped */
301
302 for (i = 0; i < nr_irqs; i++) {
303 /*
304 * Return parent uplink IRQs (towards core intc) 24,25,.....
305 * this step has been done before already
306 * however we need it to get the parent virq and set IDU handler
307 * as first level isr
308 */
309 virq = irq_of_parse_and_map(intc, i);
310 if (!i)
311 idu_first_hwirq = irqd_to_hwirq(irq_get_irq_data(virq));
312
313 irq_set_chained_handler_and_data(virq, idu_cascade_isr, domain);
314 }
315
316 __mcip_cmd(CMD_IDU_ENABLE, 0);
317
318 return 0;
319}
320IRQCHIP_DECLARE(arcv2_idu_intc, "snps,archs-idu-intc", idu_of_init);