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/smp.h>
10#include <linux/interrupt.h>
11#include <linux/init.h>
12#include <linux/cpu.h>
13#include <linux/of.h>
14#include <linux/spinlock.h>
15#include <linux/module.h>
16
17#include <asm/prom.h>
18#include <asm/io.h>
19#include <asm/smp.h>
20#include <asm/irq.h>
21#include <asm/errno.h>
22#include <asm/xics.h>
23#include <asm/kvm_ppc.h>
24#include <asm/dbell.h>
25
26struct icp_ipl {
27	union {
28		u32 word;
29		u8 bytes[4];
30	} xirr_poll;
31	union {
32		u32 word;
33		u8 bytes[4];
34	} xirr;
35	u32 dummy;
36	union {
37		u32 word;
38		u8 bytes[4];
39	} qirr;
40	u32 link_a;
41	u32 link_b;
42	u32 link_c;
43};
44
45static struct icp_ipl __iomem *icp_native_regs[NR_CPUS];
46
47static inline unsigned int icp_native_get_xirr(void)
48{
49	int cpu = smp_processor_id();
50	unsigned int xirr;
51
52	/* Handled an interrupt latched by KVM */
53	xirr = kvmppc_get_xics_latch();
54	if (xirr)
55		return xirr;
56
57	return in_be32(&icp_native_regs[cpu]->xirr.word);
58}
59
60static inline void icp_native_set_xirr(unsigned int value)
61{
62	int cpu = smp_processor_id();
63
64	out_be32(&icp_native_regs[cpu]->xirr.word, value);
65}
66
67static inline void icp_native_set_cppr(u8 value)
68{
69	int cpu = smp_processor_id();
70
71	out_8(&icp_native_regs[cpu]->xirr.bytes[0], value);
72}
73
74static inline void icp_native_set_qirr(int n_cpu, u8 value)
75{
76	out_8(&icp_native_regs[n_cpu]->qirr.bytes[0], value);
77}
78
79static void icp_native_set_cpu_priority(unsigned char cppr)
80{
81	xics_set_base_cppr(cppr);
82	icp_native_set_cppr(cppr);
83	iosync();
84}
85
86void icp_native_eoi(struct irq_data *d)
87{
88	unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
89
90	iosync();
91	icp_native_set_xirr((xics_pop_cppr() << 24) | hw_irq);
92}
93
94static void icp_native_teardown_cpu(void)
95{
96	int cpu = smp_processor_id();
97
98	/* Clear any pending IPI */
99	icp_native_set_qirr(cpu, 0xff);
100}
101
102static void icp_native_flush_ipi(void)
103{
104	/* We take the ipi irq but and never return so we
105	 * need to EOI the IPI, but want to leave our priority 0
106	 *
107	 * should we check all the other interrupts too?
108	 * should we be flagging idle loop instead?
109	 * or creating some task to be scheduled?
110	 */
111
112	icp_native_set_xirr((0x00 << 24) | XICS_IPI);
113}
114
115static unsigned int icp_native_get_irq(void)
116{
117	unsigned int xirr = icp_native_get_xirr();
118	unsigned int vec = xirr & 0x00ffffff;
119	unsigned int irq;
120
121	if (vec == XICS_IRQ_SPURIOUS)
122		return 0;
123
124	irq = irq_find_mapping(xics_host, vec);
125	if (likely(irq)) {
126		xics_push_cppr(vec);
127		return irq;
128	}
129
130	/* We don't have a linux mapping, so have rtas mask it. */
131	xics_mask_unknown_vec(vec);
132
133	/* We might learn about it later, so EOI it */
134	icp_native_set_xirr(xirr);
135
136	return 0;
137}
138
139#ifdef CONFIG_SMP
140
141static void icp_native_cause_ipi(int cpu)
142{
143	kvmppc_set_host_ipi(cpu);
144	icp_native_set_qirr(cpu, IPI_PRIORITY);
145}
146
147#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
148void icp_native_cause_ipi_rm(int cpu)
149{
150	/*
151	 * Currently not used to send IPIs to another CPU
152	 * on the same core. Only caller is KVM real mode.
153	 * Need the physical address of the XICS to be
154	 * previously saved in kvm_hstate in the paca.
155	 */
156	void __iomem *xics_phys;
157
158	/*
159	 * Just like the cause_ipi functions, it is required to
160	 * include a full barrier before causing the IPI.
161	 */
162	xics_phys = paca_ptrs[cpu]->kvm_hstate.xics_phys;
163	mb();
164	__raw_rm_writeb(IPI_PRIORITY, xics_phys + XICS_MFRR);
165}
166#endif
167
168/*
169 * Called when an interrupt is received on an off-line CPU to
170 * clear the interrupt, so that the CPU can go back to nap mode.
171 */
172void icp_native_flush_interrupt(void)
173{
174	unsigned int xirr = icp_native_get_xirr();
175	unsigned int vec = xirr & 0x00ffffff;
176
177	if (vec == XICS_IRQ_SPURIOUS)
178		return;
179	if (vec == XICS_IPI) {
180		/* Clear pending IPI */
181		int cpu = smp_processor_id();
182		kvmppc_clear_host_ipi(cpu);
183		icp_native_set_qirr(cpu, 0xff);
184	} else {
185		pr_err("XICS: hw interrupt 0x%x to offline cpu, disabling\n",
186		       vec);
187		xics_mask_unknown_vec(vec);
188	}
189	/* EOI the interrupt */
190	icp_native_set_xirr(xirr);
191}
192
193void xics_wake_cpu(int cpu)
194{
195	icp_native_set_qirr(cpu, IPI_PRIORITY);
196}
197EXPORT_SYMBOL_GPL(xics_wake_cpu);
198
199static irqreturn_t icp_native_ipi_action(int irq, void *dev_id)
200{
201	int cpu = smp_processor_id();
202
203	kvmppc_clear_host_ipi(cpu);
204	icp_native_set_qirr(cpu, 0xff);
205
206	return smp_ipi_demux();
207}
208
209#endif /* CONFIG_SMP */
210
211static int __init icp_native_map_one_cpu(int hw_id, unsigned long addr,
212					 unsigned long size)
213{
214	char *rname;
215	int i, cpu = -1;
216
217	/* This may look gross but it's good enough for now, we don't quite
218	 * have a hard -> linux processor id matching.
219	 */
220	for_each_possible_cpu(i) {
221		if (!cpu_present(i))
222			continue;
223		if (hw_id == get_hard_smp_processor_id(i)) {
224			cpu = i;
225			break;
226		}
227	}
228
229	/* Fail, skip that CPU. Don't print, it's normal, some XICS come up
230	 * with way more entries in there than you have CPUs
231	 */
232	if (cpu == -1)
233		return 0;
234
235	rname = kasprintf(GFP_KERNEL, "CPU %d [0x%x] Interrupt Presentation",
236			  cpu, hw_id);
237
238	if (!request_mem_region(addr, size, rname)) {
239		pr_warn("icp_native: Could not reserve ICP MMIO for CPU %d, interrupt server #0x%x\n",
240			cpu, hw_id);
241		return -EBUSY;
242	}
243
244	icp_native_regs[cpu] = ioremap(addr, size);
245	kvmppc_set_xics_phys(cpu, addr);
246	if (!icp_native_regs[cpu]) {
247		pr_warn("icp_native: Failed ioremap for CPU %d, interrupt server #0x%x, addr %#lx\n",
248			cpu, hw_id, addr);
249		release_mem_region(addr, size);
250		return -ENOMEM;
251	}
252	return 0;
253}
254
255static int __init icp_native_init_one_node(struct device_node *np,
256					   unsigned int *indx)
257{
258	unsigned int ilen;
259	const __be32 *ireg;
260	int i;
261	int reg_tuple_size;
262	int num_servers = 0;
263
264	/* This code does the theorically broken assumption that the interrupt
265	 * server numbers are the same as the hard CPU numbers.
266	 * This happens to be the case so far but we are playing with fire...
267	 * should be fixed one of these days. -BenH.
268	 */
269	ireg = of_get_property(np, "ibm,interrupt-server-ranges", &ilen);
270
271	/* Do that ever happen ? we'll know soon enough... but even good'old
272	 * f80 does have that property ..
273	 */
274	WARN_ON((ireg == NULL) || (ilen != 2*sizeof(u32)));
275
276	if (ireg) {
277		*indx = of_read_number(ireg, 1);
278		if (ilen >= 2*sizeof(u32))
279			num_servers = of_read_number(ireg + 1, 1);
280	}
281
282	ireg = of_get_property(np, "reg", &ilen);
283	if (!ireg) {
284		pr_err("icp_native: Can't find interrupt reg property");
285		return -1;
286	}
287
288	reg_tuple_size = (of_n_addr_cells(np) + of_n_size_cells(np)) * 4;
289	if (((ilen % reg_tuple_size) != 0)
290	    || (num_servers && (num_servers != (ilen / reg_tuple_size)))) {
291		pr_err("icp_native: ICP reg len (%d) != num servers (%d)",
292		       ilen / reg_tuple_size, num_servers);
293		return -1;
294	}
295
296	for (i = 0; i < (ilen / reg_tuple_size); i++) {
297		struct resource r;
298		int err;
299
300		err = of_address_to_resource(np, i, &r);
301		if (err) {
302			pr_err("icp_native: Could not translate ICP MMIO"
303			       " for interrupt server 0x%x (%d)\n", *indx, err);
304			return -1;
305		}
306
307		if (icp_native_map_one_cpu(*indx, r.start, resource_size(&r)))
308			return -1;
309
310		(*indx)++;
311	}
312	return 0;
313}
314
315static const struct icp_ops icp_native_ops = {
316	.get_irq	= icp_native_get_irq,
317	.eoi		= icp_native_eoi,
318	.set_priority	= icp_native_set_cpu_priority,
319	.teardown_cpu	= icp_native_teardown_cpu,
320	.flush_ipi	= icp_native_flush_ipi,
321#ifdef CONFIG_SMP
322	.ipi_action	= icp_native_ipi_action,
323	.cause_ipi	= icp_native_cause_ipi,
324#endif
325};
326
327int __init icp_native_init(void)
328{
329	struct device_node *np;
330	u32 indx = 0;
331	int found = 0;
332
333	for_each_compatible_node(np, NULL, "ibm,ppc-xicp")
334		if (icp_native_init_one_node(np, &indx) == 0)
335			found = 1;
336	if (!found) {
337		for_each_node_by_type(np,
338			"PowerPC-External-Interrupt-Presentation") {
339				if (icp_native_init_one_node(np, &indx) == 0)
340					found = 1;
341		}
342	}
343
344	if (found == 0)
345		return -ENODEV;
346
347	icp_ops = &icp_native_ops;
348
349	return 0;
350}
351