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