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 */
21 static int ibm_get_xive;
22 static int ibm_set_xive;
23 static int ibm_int_on;
24 static int ibm_int_off;
25 
26 static int ics_rtas_map(struct ics *ics, unsigned int virq);
27 static void ics_rtas_mask_unknown(struct ics *ics, unsigned long vec);
28 static long ics_rtas_get_server(struct ics *ics, unsigned long vec);
29 static int ics_rtas_host_match(struct ics *ics, struct device_node *node);
30 
31 /* Only one global & state struct ics */
32 static 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 
39 static 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 
70 static 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 
86 static 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 
110 static 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 
121 static 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 
160 static 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 
169 static 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 
189 static void ics_rtas_mask_unknown(struct ics *ics, unsigned long vec)
190 {
191 	ics_rtas_mask_real_irq(vec);
192 }
193 
194 static 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 
204 static 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