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