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
27struct 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
46static struct icp_ipl __iomem *icp_native_regs[NR_CPUS];
47
48static 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
61static 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
68static 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
75static 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
80static 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
87void 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
95static 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
103static 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
116static 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
142static 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
149void 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 */
173void 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
194void xics_wake_cpu(int cpu)
195{
196	icp_native_set_qirr(cpu, IPI_PRIORITY);
197}
198EXPORT_SYMBOL_GPL(xics_wake_cpu);
199
200static 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
212static 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 (!request_mem_region(addr, size, rname)) {
240		pr_warn("icp_native: Could not reserve ICP MMIO for CPU %d, interrupt server #0x%x\n",
241			cpu, hw_id);
242		return -EBUSY;
243	}
244
245	icp_native_regs[cpu] = ioremap(addr, size);
246	kvmppc_set_xics_phys(cpu, addr);
247	if (!icp_native_regs[cpu]) {
248		pr_warn("icp_native: Failed ioremap for CPU %d, interrupt server #0x%x, addr %#lx\n",
249			cpu, hw_id, addr);
250		release_mem_region(addr, size);
251		return -ENOMEM;
252	}
253	return 0;
254}
255
256static int __init icp_native_init_one_node(struct device_node *np,
257					   unsigned int *indx)
258{
259	unsigned int ilen;
260	const __be32 *ireg;
261	int i;
262	int num_reg;
263	int num_servers = 0;
264
265	/* This code does the theorically broken assumption that the interrupt
266	 * server numbers are the same as the hard CPU numbers.
267	 * This happens to be the case so far but we are playing with fire...
268	 * should be fixed one of these days. -BenH.
269	 */
270	ireg = of_get_property(np, "ibm,interrupt-server-ranges", &ilen);
271
272	/* Do that ever happen ? we'll know soon enough... but even good'old
273	 * f80 does have that property ..
274	 */
275	WARN_ON((ireg == NULL) || (ilen != 2*sizeof(u32)));
276
277	if (ireg) {
278		*indx = of_read_number(ireg, 1);
279		if (ilen >= 2*sizeof(u32))
280			num_servers = of_read_number(ireg + 1, 1);
281	}
282
283	num_reg = of_address_count(np);
284	if (num_servers && (num_servers != num_reg)) {
285		pr_err("icp_native: ICP reg len (%d) != num servers (%d)",
286		       num_reg, num_servers);
287		return -1;
288	}
289
290	for (i = 0; i < num_reg; i++) {
291		struct resource r;
292		int err;
293
294		err = of_address_to_resource(np, i, &r);
295		if (err) {
296			pr_err("icp_native: Could not translate ICP MMIO"
297			       " for interrupt server 0x%x (%d)\n", *indx, err);
298			return -1;
299		}
300
301		if (icp_native_map_one_cpu(*indx, r.start, resource_size(&r)))
302			return -1;
303
304		(*indx)++;
305	}
306	return 0;
307}
308
309static const struct icp_ops icp_native_ops = {
310	.get_irq	= icp_native_get_irq,
311	.eoi		= icp_native_eoi,
312	.set_priority	= icp_native_set_cpu_priority,
313	.teardown_cpu	= icp_native_teardown_cpu,
314	.flush_ipi	= icp_native_flush_ipi,
315#ifdef CONFIG_SMP
316	.ipi_action	= icp_native_ipi_action,
317	.cause_ipi	= icp_native_cause_ipi,
318#endif
319};
320
321int __init icp_native_init(void)
322{
323	struct device_node *np;
324	u32 indx = 0;
325	int found = 0;
326
327	for_each_compatible_node(np, NULL, "ibm,ppc-xicp")
328		if (icp_native_init_one_node(np, &indx) == 0)
329			found = 1;
330	if (!found) {
331		for_each_node_by_type(np,
332			"PowerPC-External-Interrupt-Presentation") {
333				if (icp_native_init_one_node(np, &indx) == 0)
334					found = 1;
335		}
336	}
337
338	if (found == 0)
339		return -ENODEV;
340
341	icp_ops = &icp_native_ops;
342
343	return 0;
344}
345