1// SPDX-License-Identifier: GPL-2.0
2#include <linux/types.h>
3#include <linux/kernel.h>
4#include <linux/irq.h>
5#include <linux/smp.h>
6#include <linux/interrupt.h>
7#include <linux/init.h>
8#include <linux/cpu.h>
9#include <linux/of.h>
10#include <linux/spinlock.h>
11#include <linux/msi.h>
12
13#include <asm/prom.h>
14#include <asm/smp.h>
15#include <asm/machdep.h>
16#include <asm/irq.h>
17#include <asm/errno.h>
18#include <asm/xics.h>
19#include <asm/rtas.h>
20
21/* RTAS service tokens */
22static int ibm_get_xive;
23static int ibm_set_xive;
24static int ibm_int_on;
25static int ibm_int_off;
26
27static int ics_rtas_map(struct ics *ics, unsigned int virq);
28static void ics_rtas_mask_unknown(struct ics *ics, unsigned long vec);
29static long ics_rtas_get_server(struct ics *ics, unsigned long vec);
30static int ics_rtas_host_match(struct ics *ics, struct device_node *node);
31
32/* Only one global & state struct ics */
33static struct ics ics_rtas = {
34	.map		= ics_rtas_map,
35	.mask_unknown	= ics_rtas_mask_unknown,
36	.get_server	= ics_rtas_get_server,
37	.host_match	= ics_rtas_host_match,
38};
39
40static void ics_rtas_unmask_irq(struct irq_data *d)
41{
42	unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
43	int call_status;
44	int server;
45
46	pr_devel("xics: unmask virq %d [hw 0x%x]\n", d->irq, hw_irq);
47
48	if (hw_irq == XICS_IPI || hw_irq == XICS_IRQ_SPURIOUS)
49		return;
50
51	server = xics_get_irq_server(d->irq, irq_data_get_affinity_mask(d), 0);
52
53	call_status = rtas_call_reentrant(ibm_set_xive, 3, 1, NULL, hw_irq,
54					  server, DEFAULT_PRIORITY);
55	if (call_status != 0) {
56		printk(KERN_ERR
57			"%s: ibm_set_xive irq %u server %x returned %d\n",
58			__func__, hw_irq, server, call_status);
59		return;
60	}
61
62	/* Now unmask the interrupt (often a no-op) */
63	call_status = rtas_call_reentrant(ibm_int_on, 1, 1, NULL, hw_irq);
64	if (call_status != 0) {
65		printk(KERN_ERR "%s: ibm_int_on irq=%u returned %d\n",
66			__func__, hw_irq, call_status);
67		return;
68	}
69}
70
71static unsigned int ics_rtas_startup(struct irq_data *d)
72{
73#ifdef CONFIG_PCI_MSI
74	/*
75	 * The generic MSI code returns with the interrupt disabled on the
76	 * card, using the MSI mask bits. Firmware doesn't appear to unmask
77	 * at that level, so we do it here by hand.
78	 */
79	if (irq_data_get_msi_desc(d))
80		pci_msi_unmask_irq(d);
81#endif
82	/* unmask it */
83	ics_rtas_unmask_irq(d);
84	return 0;
85}
86
87static void ics_rtas_mask_real_irq(unsigned int hw_irq)
88{
89	int call_status;
90
91	if (hw_irq == XICS_IPI)
92		return;
93
94	call_status = rtas_call_reentrant(ibm_int_off, 1, 1, NULL, hw_irq);
95	if (call_status != 0) {
96		printk(KERN_ERR "%s: ibm_int_off irq=%u returned %d\n",
97			__func__, hw_irq, call_status);
98		return;
99	}
100
101	/* Have to set XIVE to 0xff to be able to remove a slot */
102	call_status = rtas_call_reentrant(ibm_set_xive, 3, 1, NULL, hw_irq,
103					  xics_default_server, 0xff);
104	if (call_status != 0) {
105		printk(KERN_ERR "%s: ibm_set_xive(0xff) irq=%u returned %d\n",
106			__func__, hw_irq, call_status);
107		return;
108	}
109}
110
111static void ics_rtas_mask_irq(struct irq_data *d)
112{
113	unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
114
115	pr_devel("xics: mask virq %d [hw 0x%x]\n", d->irq, hw_irq);
116
117	if (hw_irq == XICS_IPI || hw_irq == XICS_IRQ_SPURIOUS)
118		return;
119	ics_rtas_mask_real_irq(hw_irq);
120}
121
122static int ics_rtas_set_affinity(struct irq_data *d,
123				 const struct cpumask *cpumask,
124				 bool force)
125{
126	unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
127	int status;
128	int xics_status[2];
129	int irq_server;
130
131	if (hw_irq == XICS_IPI || hw_irq == XICS_IRQ_SPURIOUS)
132		return -1;
133
134	status = rtas_call_reentrant(ibm_get_xive, 1, 3, xics_status, hw_irq);
135
136	if (status) {
137		printk(KERN_ERR "%s: ibm,get-xive irq=%u returns %d\n",
138			__func__, hw_irq, status);
139		return -1;
140	}
141
142	irq_server = xics_get_irq_server(d->irq, cpumask, 1);
143	if (irq_server == -1) {
144		pr_warn("%s: No online cpus in the mask %*pb for irq %d\n",
145			__func__, cpumask_pr_args(cpumask), d->irq);
146		return -1;
147	}
148
149	status = rtas_call_reentrant(ibm_set_xive, 3, 1, NULL,
150				     hw_irq, irq_server, xics_status[1]);
151
152	if (status) {
153		printk(KERN_ERR "%s: ibm,set-xive irq=%u returns %d\n",
154			__func__, hw_irq, status);
155		return -1;
156	}
157
158	return IRQ_SET_MASK_OK;
159}
160
161static struct irq_chip ics_rtas_irq_chip = {
162	.name = "XICS",
163	.irq_startup = ics_rtas_startup,
164	.irq_mask = ics_rtas_mask_irq,
165	.irq_unmask = ics_rtas_unmask_irq,
166	.irq_eoi = NULL, /* Patched at init time */
167	.irq_set_affinity = ics_rtas_set_affinity,
168	.irq_set_type = xics_set_irq_type,
169	.irq_retrigger = xics_retrigger,
170};
171
172static int ics_rtas_map(struct ics *ics, unsigned int virq)
173{
174	unsigned int hw_irq = (unsigned int)virq_to_hw(virq);
175	int status[2];
176	int rc;
177
178	if (WARN_ON(hw_irq == XICS_IPI || hw_irq == XICS_IRQ_SPURIOUS))
179		return -EINVAL;
180
181	/* Check if RTAS knows about this interrupt */
182	rc = rtas_call_reentrant(ibm_get_xive, 1, 3, status, hw_irq);
183	if (rc)
184		return -ENXIO;
185
186	irq_set_chip_and_handler(virq, &ics_rtas_irq_chip, handle_fasteoi_irq);
187	irq_set_chip_data(virq, &ics_rtas);
188
189	return 0;
190}
191
192static void ics_rtas_mask_unknown(struct ics *ics, unsigned long vec)
193{
194	ics_rtas_mask_real_irq(vec);
195}
196
197static long ics_rtas_get_server(struct ics *ics, unsigned long vec)
198{
199	int rc, status[2];
200
201	rc = rtas_call_reentrant(ibm_get_xive, 1, 3, status, vec);
202	if (rc)
203		return -1;
204	return status[0];
205}
206
207static int ics_rtas_host_match(struct ics *ics, struct device_node *node)
208{
209	/* IBM machines have interrupt parents of various funky types for things
210	 * like vdevices, events, etc... The trick we use here is to match
211	 * everything here except the legacy 8259 which is compatible "chrp,iic"
212	 */
213	return !of_device_is_compatible(node, "chrp,iic");
214}
215
216__init int ics_rtas_init(void)
217{
218	ibm_get_xive = rtas_token("ibm,get-xive");
219	ibm_set_xive = rtas_token("ibm,set-xive");
220	ibm_int_on  = rtas_token("ibm,int-on");
221	ibm_int_off = rtas_token("ibm,int-off");
222
223	/* We enable the RTAS "ICS" if RTAS is present with the
224	 * appropriate tokens
225	 */
226	if (ibm_get_xive == RTAS_UNKNOWN_SERVICE ||
227	    ibm_set_xive == RTAS_UNKNOWN_SERVICE)
228		return -ENODEV;
229
230	/* We need to patch our irq chip's EOI to point to the
231	 * right ICP
232	 */
233	ics_rtas_irq_chip.irq_eoi = icp_ops->eoi;
234
235	/* Register ourselves */
236	xics_register_ics(&ics_rtas);
237
238	return 0;
239}
240
241