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 
icp_native_get_xirr(void)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 
icp_native_set_xirr(unsigned int value)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 
icp_native_set_cppr(u8 value)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 
icp_native_set_qirr(int n_cpu,u8 value)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 
icp_native_set_cpu_priority(unsigned char cppr)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 
icp_native_eoi(struct irq_data * d)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 
icp_native_teardown_cpu(void)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 
icp_native_flush_ipi(void)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 
icp_native_get_irq(void)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 
icp_native_cause_ipi(int cpu)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 /*
149  * Called when an interrupt is received on an off-line CPU to
150  * clear the interrupt, so that the CPU can go back to nap mode.
151  */
icp_native_flush_interrupt(void)152 void icp_native_flush_interrupt(void)
153 {
154 	unsigned int xirr = icp_native_get_xirr();
155 	unsigned int vec = xirr & 0x00ffffff;
156 
157 	if (vec == XICS_IRQ_SPURIOUS)
158 		return;
159 	if (vec == XICS_IPI) {
160 		/* Clear pending IPI */
161 		int cpu = smp_processor_id();
162 		kvmppc_clear_host_ipi(cpu);
163 		icp_native_set_qirr(cpu, 0xff);
164 	} else {
165 		pr_err("XICS: hw interrupt 0x%x to offline cpu, disabling\n",
166 		       vec);
167 		xics_mask_unknown_vec(vec);
168 	}
169 	/* EOI the interrupt */
170 	icp_native_set_xirr(xirr);
171 }
172 
xics_wake_cpu(int cpu)173 void xics_wake_cpu(int cpu)
174 {
175 	icp_native_set_qirr(cpu, IPI_PRIORITY);
176 }
177 EXPORT_SYMBOL_GPL(xics_wake_cpu);
178 
icp_native_ipi_action(int irq,void * dev_id)179 static irqreturn_t icp_native_ipi_action(int irq, void *dev_id)
180 {
181 	int cpu = smp_processor_id();
182 
183 	kvmppc_clear_host_ipi(cpu);
184 	icp_native_set_qirr(cpu, 0xff);
185 
186 	return smp_ipi_demux();
187 }
188 
189 #endif /* CONFIG_SMP */
190 
icp_native_map_one_cpu(int hw_id,unsigned long addr,unsigned long size)191 static int __init icp_native_map_one_cpu(int hw_id, unsigned long addr,
192 					 unsigned long size)
193 {
194 	char *rname;
195 	int i, cpu = -1;
196 
197 	/* This may look gross but it's good enough for now, we don't quite
198 	 * have a hard -> linux processor id matching.
199 	 */
200 	for_each_possible_cpu(i) {
201 		if (!cpu_present(i))
202 			continue;
203 		if (hw_id == get_hard_smp_processor_id(i)) {
204 			cpu = i;
205 			break;
206 		}
207 	}
208 
209 	/* Fail, skip that CPU. Don't print, it's normal, some XICS come up
210 	 * with way more entries in there than you have CPUs
211 	 */
212 	if (cpu == -1)
213 		return 0;
214 
215 	rname = kasprintf(GFP_KERNEL, "CPU %d [0x%x] Interrupt Presentation",
216 			  cpu, hw_id);
217 
218 	if (!rname)
219 		return -ENOMEM;
220 	if (!request_mem_region(addr, size, rname)) {
221 		pr_warn("icp_native: Could not reserve ICP MMIO for CPU %d, interrupt server #0x%x\n",
222 			cpu, hw_id);
223 		return -EBUSY;
224 	}
225 
226 	icp_native_regs[cpu] = ioremap(addr, size);
227 	kvmppc_set_xics_phys(cpu, addr);
228 	if (!icp_native_regs[cpu]) {
229 		pr_warn("icp_native: Failed ioremap for CPU %d, interrupt server #0x%x, addr %#lx\n",
230 			cpu, hw_id, addr);
231 		release_mem_region(addr, size);
232 		return -ENOMEM;
233 	}
234 	return 0;
235 }
236 
icp_native_init_one_node(struct device_node * np,unsigned int * indx)237 static int __init icp_native_init_one_node(struct device_node *np,
238 					   unsigned int *indx)
239 {
240 	unsigned int ilen;
241 	const __be32 *ireg;
242 	int i;
243 	int num_reg;
244 	int num_servers = 0;
245 
246 	/* This code does the theorically broken assumption that the interrupt
247 	 * server numbers are the same as the hard CPU numbers.
248 	 * This happens to be the case so far but we are playing with fire...
249 	 * should be fixed one of these days. -BenH.
250 	 */
251 	ireg = of_get_property(np, "ibm,interrupt-server-ranges", &ilen);
252 
253 	/* Do that ever happen ? we'll know soon enough... but even good'old
254 	 * f80 does have that property ..
255 	 */
256 	WARN_ON((ireg == NULL) || (ilen != 2*sizeof(u32)));
257 
258 	if (ireg) {
259 		*indx = of_read_number(ireg, 1);
260 		if (ilen >= 2*sizeof(u32))
261 			num_servers = of_read_number(ireg + 1, 1);
262 	}
263 
264 	num_reg = of_address_count(np);
265 	if (num_servers && (num_servers != num_reg)) {
266 		pr_err("icp_native: ICP reg len (%d) != num servers (%d)",
267 		       num_reg, num_servers);
268 		return -1;
269 	}
270 
271 	for (i = 0; i < num_reg; i++) {
272 		struct resource r;
273 		int err;
274 
275 		err = of_address_to_resource(np, i, &r);
276 		if (err) {
277 			pr_err("icp_native: Could not translate ICP MMIO"
278 			       " for interrupt server 0x%x (%d)\n", *indx, err);
279 			return -1;
280 		}
281 
282 		if (icp_native_map_one_cpu(*indx, r.start, resource_size(&r)))
283 			return -1;
284 
285 		(*indx)++;
286 	}
287 	return 0;
288 }
289 
290 static const struct icp_ops icp_native_ops = {
291 	.get_irq	= icp_native_get_irq,
292 	.eoi		= icp_native_eoi,
293 	.set_priority	= icp_native_set_cpu_priority,
294 	.teardown_cpu	= icp_native_teardown_cpu,
295 	.flush_ipi	= icp_native_flush_ipi,
296 #ifdef CONFIG_SMP
297 	.ipi_action	= icp_native_ipi_action,
298 	.cause_ipi	= icp_native_cause_ipi,
299 #endif
300 };
301 
icp_native_init(void)302 int __init icp_native_init(void)
303 {
304 	struct device_node *np;
305 	u32 indx = 0;
306 	int found = 0;
307 
308 	for_each_compatible_node(np, NULL, "ibm,ppc-xicp")
309 		if (icp_native_init_one_node(np, &indx) == 0)
310 			found = 1;
311 	if (!found) {
312 		for_each_node_by_type(np,
313 			"PowerPC-External-Interrupt-Presentation") {
314 				if (icp_native_init_one_node(np, &indx) == 0)
315 					found = 1;
316 		}
317 	}
318 
319 	if (found == 0)
320 		return -ENODEV;
321 
322 	icp_ops = &icp_native_ops;
323 
324 	return 0;
325 }
326