1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright 2011 IBM Corporation.
4 */
5
6 #include <linux/types.h>
7 #include <linux/kernel.h>
8 #include <linux/irq.h>
9 #include <linux/irqdomain.h>
10 #include <linux/smp.h>
11 #include <linux/interrupt.h>
12 #include <linux/init.h>
13 #include <linux/cpu.h>
14 #include <linux/of.h>
15 #include <linux/of_address.h>
16 #include <linux/spinlock.h>
17 #include <linux/module.h>
18
19 #include <asm/io.h>
20 #include <asm/smp.h>
21 #include <asm/irq.h>
22 #include <asm/errno.h>
23 #include <asm/xics.h>
24 #include <asm/kvm_ppc.h>
25 #include <asm/dbell.h>
26
27 struct icp_ipl {
28 union {
29 u32 word;
30 u8 bytes[4];
31 } xirr_poll;
32 union {
33 u32 word;
34 u8 bytes[4];
35 } xirr;
36 u32 dummy;
37 union {
38 u32 word;
39 u8 bytes[4];
40 } qirr;
41 u32 link_a;
42 u32 link_b;
43 u32 link_c;
44 };
45
46 static struct icp_ipl __iomem *icp_native_regs[NR_CPUS];
47
48 static inline unsigned int icp_native_get_xirr(void)
49 {
50 int cpu = smp_processor_id();
51 unsigned int xirr;
52
53 /* Handled an interrupt latched by KVM */
54 xirr = kvmppc_get_xics_latch();
55 if (xirr)
56 return xirr;
57
58 return in_be32(&icp_native_regs[cpu]->xirr.word);
59 }
60
61 static inline void icp_native_set_xirr(unsigned int value)
62 {
63 int cpu = smp_processor_id();
64
65 out_be32(&icp_native_regs[cpu]->xirr.word, value);
66 }
67
68 static inline void icp_native_set_cppr(u8 value)
69 {
70 int cpu = smp_processor_id();
71
72 out_8(&icp_native_regs[cpu]->xirr.bytes[0], value);
73 }
74
75 static inline void icp_native_set_qirr(int n_cpu, u8 value)
76 {
77 out_8(&icp_native_regs[n_cpu]->qirr.bytes[0], value);
78 }
79
80 static void icp_native_set_cpu_priority(unsigned char cppr)
81 {
82 xics_set_base_cppr(cppr);
83 icp_native_set_cppr(cppr);
84 iosync();
85 }
86
87 void icp_native_eoi(struct irq_data *d)
88 {
89 unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
90
91 iosync();
92 icp_native_set_xirr((xics_pop_cppr() << 24) | hw_irq);
93 }
94
95 static void icp_native_teardown_cpu(void)
96 {
97 int cpu = smp_processor_id();
98
99 /* Clear any pending IPI */
100 icp_native_set_qirr(cpu, 0xff);
101 }
102
103 static void icp_native_flush_ipi(void)
104 {
105 /* We take the ipi irq but and never return so we
106 * need to EOI the IPI, but want to leave our priority 0
107 *
108 * should we check all the other interrupts too?
109 * should we be flagging idle loop instead?
110 * or creating some task to be scheduled?
111 */
112
113 icp_native_set_xirr((0x00 << 24) | XICS_IPI);
114 }
115
116 static unsigned int icp_native_get_irq(void)
117 {
118 unsigned int xirr = icp_native_get_xirr();
119 unsigned int vec = xirr & 0x00ffffff;
120 unsigned int irq;
121
122 if (vec == XICS_IRQ_SPURIOUS)
123 return 0;
124
125 irq = irq_find_mapping(xics_host, vec);
126 if (likely(irq)) {
127 xics_push_cppr(vec);
128 return irq;
129 }
130
131 /* We don't have a linux mapping, so have rtas mask it. */
132 xics_mask_unknown_vec(vec);
133
134 /* We might learn about it later, so EOI it */
135 icp_native_set_xirr(xirr);
136
137 return 0;
138 }
139
140 #ifdef CONFIG_SMP
141
142 static void icp_native_cause_ipi(int cpu)
143 {
144 kvmppc_set_host_ipi(cpu);
145 icp_native_set_qirr(cpu, IPI_PRIORITY);
146 }
147
148 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
149 void icp_native_cause_ipi_rm(int cpu)
150 {
151 /*
152 * Currently not used to send IPIs to another CPU
153 * on the same core. Only caller is KVM real mode.
154 * Need the physical address of the XICS to be
155 * previously saved in kvm_hstate in the paca.
156 */
157 void __iomem *xics_phys;
158
159 /*
160 * Just like the cause_ipi functions, it is required to
161 * include a full barrier before causing the IPI.
162 */
163 xics_phys = paca_ptrs[cpu]->kvm_hstate.xics_phys;
164 mb();
165 __raw_rm_writeb(IPI_PRIORITY, xics_phys + XICS_MFRR);
166 }
167 #endif
168
169 /*
170 * Called when an interrupt is received on an off-line CPU to
171 * clear the interrupt, so that the CPU can go back to nap mode.
172 */
173 void icp_native_flush_interrupt(void)
174 {
175 unsigned int xirr = icp_native_get_xirr();
176 unsigned int vec = xirr & 0x00ffffff;
177
178 if (vec == XICS_IRQ_SPURIOUS)
179 return;
180 if (vec == XICS_IPI) {
181 /* Clear pending IPI */
182 int cpu = smp_processor_id();
183 kvmppc_clear_host_ipi(cpu);
184 icp_native_set_qirr(cpu, 0xff);
185 } else {
186 pr_err("XICS: hw interrupt 0x%x to offline cpu, disabling\n",
187 vec);
188 xics_mask_unknown_vec(vec);
189 }
190 /* EOI the interrupt */
191 icp_native_set_xirr(xirr);
192 }
193
194 void xics_wake_cpu(int cpu)
195 {
196 icp_native_set_qirr(cpu, IPI_PRIORITY);
197 }
198 EXPORT_SYMBOL_GPL(xics_wake_cpu);
199
200 static irqreturn_t icp_native_ipi_action(int irq, void *dev_id)
201 {
202 int cpu = smp_processor_id();
203
204 kvmppc_clear_host_ipi(cpu);
205 icp_native_set_qirr(cpu, 0xff);
206
207 return smp_ipi_demux();
208 }
209
210 #endif /* CONFIG_SMP */
211
212 static int __init icp_native_map_one_cpu(int hw_id, unsigned long addr,
213 unsigned long size)
214 {
215 char *rname;
216 int i, cpu = -1;
217
218 /* This may look gross but it's good enough for now, we don't quite
219 * have a hard -> linux processor id matching.
220 */
221 for_each_possible_cpu(i) {
222 if (!cpu_present(i))
223 continue;
224 if (hw_id == get_hard_smp_processor_id(i)) {
225 cpu = i;
226 break;
227 }
228 }
229
230 /* Fail, skip that CPU. Don't print, it's normal, some XICS come up
231 * with way more entries in there than you have CPUs
232 */
233 if (cpu == -1)
234 return 0;
235
236 rname = kasprintf(GFP_KERNEL, "CPU %d [0x%x] Interrupt Presentation",
237 cpu, hw_id);
238
239 if (!rname)
240 return -ENOMEM;
241 if (!request_mem_region(addr, size, rname)) {
242 pr_warn("icp_native: Could not reserve ICP MMIO for CPU %d, interrupt server #0x%x\n",
243 cpu, hw_id);
244 return -EBUSY;
245 }
246
247 icp_native_regs[cpu] = ioremap(addr, size);
248 kvmppc_set_xics_phys(cpu, addr);
249 if (!icp_native_regs[cpu]) {
250 pr_warn("icp_native: Failed ioremap for CPU %d, interrupt server #0x%x, addr %#lx\n",
251 cpu, hw_id, addr);
252 release_mem_region(addr, size);
253 return -ENOMEM;
254 }
255 return 0;
256 }
257
258 static int __init icp_native_init_one_node(struct device_node *np,
259 unsigned int *indx)
260 {
261 unsigned int ilen;
262 const __be32 *ireg;
263 int i;
264 int num_reg;
265 int num_servers = 0;
266
267 /* This code does the theorically broken assumption that the interrupt
268 * server numbers are the same as the hard CPU numbers.
269 * This happens to be the case so far but we are playing with fire...
270 * should be fixed one of these days. -BenH.
271 */
272 ireg = of_get_property(np, "ibm,interrupt-server-ranges", &ilen);
273
274 /* Do that ever happen ? we'll know soon enough... but even good'old
275 * f80 does have that property ..
276 */
277 WARN_ON((ireg == NULL) || (ilen != 2*sizeof(u32)));
278
279 if (ireg) {
280 *indx = of_read_number(ireg, 1);
281 if (ilen >= 2*sizeof(u32))
282 num_servers = of_read_number(ireg + 1, 1);
283 }
284
285 num_reg = of_address_count(np);
286 if (num_servers && (num_servers != num_reg)) {
287 pr_err("icp_native: ICP reg len (%d) != num servers (%d)",
288 num_reg, num_servers);
289 return -1;
290 }
291
292 for (i = 0; i < num_reg; i++) {
293 struct resource r;
294 int err;
295
296 err = of_address_to_resource(np, i, &r);
297 if (err) {
298 pr_err("icp_native: Could not translate ICP MMIO"
299 " for interrupt server 0x%x (%d)\n", *indx, err);
300 return -1;
301 }
302
303 if (icp_native_map_one_cpu(*indx, r.start, resource_size(&r)))
304 return -1;
305
306 (*indx)++;
307 }
308 return 0;
309 }
310
311 static const struct icp_ops icp_native_ops = {
312 .get_irq = icp_native_get_irq,
313 .eoi = icp_native_eoi,
314 .set_priority = icp_native_set_cpu_priority,
315 .teardown_cpu = icp_native_teardown_cpu,
316 .flush_ipi = icp_native_flush_ipi,
317 #ifdef CONFIG_SMP
318 .ipi_action = icp_native_ipi_action,
319 .cause_ipi = icp_native_cause_ipi,
320 #endif
321 };
322
323 int __init icp_native_init(void)
324 {
325 struct device_node *np;
326 u32 indx = 0;
327 int found = 0;
328
329 for_each_compatible_node(np, NULL, "ibm,ppc-xicp")
330 if (icp_native_init_one_node(np, &indx) == 0)
331 found = 1;
332 if (!found) {
333 for_each_node_by_type(np,
334 "PowerPC-External-Interrupt-Presentation") {
335 if (icp_native_init_one_node(np, &indx) == 0)
336 found = 1;
337 }
338 }
339
340 if (found == 0)
341 return -ENODEV;
342
343 icp_ops = &icp_native_ops;
344
345 return 0;
346 }
347
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