1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright 2006, Segher Boessenkool, IBM Corporation.
4 * Copyright 2006-2007, Michael Ellerman, IBM Corporation.
5 */
6
7 #include <linux/irq.h>
8 #include <linux/msi.h>
9 #include <asm/mpic.h>
10 #include <asm/prom.h>
11 #include <asm/hw_irq.h>
12 #include <asm/ppc-pci.h>
13 #include <asm/msi_bitmap.h>
14
15 #include "mpic.h"
16
17 /* A bit ugly, can we get this from the pci_dev somehow? */
18 static struct mpic *msi_mpic;
19
mpic_u3msi_mask_irq(struct irq_data * data)20 static void mpic_u3msi_mask_irq(struct irq_data *data)
21 {
22 pci_msi_mask_irq(data);
23 mpic_mask_irq(data);
24 }
25
mpic_u3msi_unmask_irq(struct irq_data * data)26 static void mpic_u3msi_unmask_irq(struct irq_data *data)
27 {
28 mpic_unmask_irq(data);
29 pci_msi_unmask_irq(data);
30 }
31
32 static struct irq_chip mpic_u3msi_chip = {
33 .irq_shutdown = mpic_u3msi_mask_irq,
34 .irq_mask = mpic_u3msi_mask_irq,
35 .irq_unmask = mpic_u3msi_unmask_irq,
36 .irq_eoi = mpic_end_irq,
37 .irq_set_type = mpic_set_irq_type,
38 .irq_set_affinity = mpic_set_affinity,
39 .name = "MPIC-U3MSI",
40 };
41
read_ht_magic_addr(struct pci_dev * pdev,unsigned int pos)42 static u64 read_ht_magic_addr(struct pci_dev *pdev, unsigned int pos)
43 {
44 u8 flags;
45 u32 tmp;
46 u64 addr;
47
48 pci_read_config_byte(pdev, pos + HT_MSI_FLAGS, &flags);
49
50 if (flags & HT_MSI_FLAGS_FIXED)
51 return HT_MSI_FIXED_ADDR;
52
53 pci_read_config_dword(pdev, pos + HT_MSI_ADDR_LO, &tmp);
54 addr = tmp & HT_MSI_ADDR_LO_MASK;
55 pci_read_config_dword(pdev, pos + HT_MSI_ADDR_HI, &tmp);
56 addr = addr | ((u64)tmp << 32);
57
58 return addr;
59 }
60
find_ht_magic_addr(struct pci_dev * pdev,unsigned int hwirq)61 static u64 find_ht_magic_addr(struct pci_dev *pdev, unsigned int hwirq)
62 {
63 struct pci_bus *bus;
64 unsigned int pos;
65
66 for (bus = pdev->bus; bus && bus->self; bus = bus->parent) {
67 pos = pci_find_ht_capability(bus->self, HT_CAPTYPE_MSI_MAPPING);
68 if (pos)
69 return read_ht_magic_addr(bus->self, pos);
70 }
71
72 return 0;
73 }
74
find_u4_magic_addr(struct pci_dev * pdev,unsigned int hwirq)75 static u64 find_u4_magic_addr(struct pci_dev *pdev, unsigned int hwirq)
76 {
77 struct pci_controller *hose = pci_bus_to_host(pdev->bus);
78
79 /* U4 PCIe MSIs need to write to the special register in
80 * the bridge that generates interrupts. There should be
81 * theorically a register at 0xf8005000 where you just write
82 * the MSI number and that triggers the right interrupt, but
83 * unfortunately, this is busted in HW, the bridge endian swaps
84 * the value and hits the wrong nibble in the register.
85 *
86 * So instead we use another register set which is used normally
87 * for converting HT interrupts to MPIC interrupts, which decodes
88 * the interrupt number as part of the low address bits
89 *
90 * This will not work if we ever use more than one legacy MSI in
91 * a block but we never do. For one MSI or multiple MSI-X where
92 * each interrupt address can be specified separately, it works
93 * just fine.
94 */
95 if (of_device_is_compatible(hose->dn, "u4-pcie") ||
96 of_device_is_compatible(hose->dn, "U4-pcie"))
97 return 0xf8004000 | (hwirq << 4);
98
99 return 0;
100 }
101
u3msi_teardown_msi_irqs(struct pci_dev * pdev)102 static void u3msi_teardown_msi_irqs(struct pci_dev *pdev)
103 {
104 struct msi_desc *entry;
105 irq_hw_number_t hwirq;
106
107 for_each_pci_msi_entry(entry, pdev) {
108 if (!entry->irq)
109 continue;
110
111 hwirq = virq_to_hw(entry->irq);
112 irq_set_msi_desc(entry->irq, NULL);
113 irq_dispose_mapping(entry->irq);
114 msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, 1);
115 }
116
117 return;
118 }
119
u3msi_setup_msi_irqs(struct pci_dev * pdev,int nvec,int type)120 static int u3msi_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
121 {
122 unsigned int virq;
123 struct msi_desc *entry;
124 struct msi_msg msg;
125 u64 addr;
126 int hwirq;
127
128 if (type == PCI_CAP_ID_MSIX)
129 pr_debug("u3msi: MSI-X untested, trying anyway.\n");
130
131 /* If we can't find a magic address then MSI ain't gonna work */
132 if (find_ht_magic_addr(pdev, 0) == 0 &&
133 find_u4_magic_addr(pdev, 0) == 0) {
134 pr_debug("u3msi: no magic address found for %s\n",
135 pci_name(pdev));
136 return -ENXIO;
137 }
138
139 for_each_pci_msi_entry(entry, pdev) {
140 hwirq = msi_bitmap_alloc_hwirqs(&msi_mpic->msi_bitmap, 1);
141 if (hwirq < 0) {
142 pr_debug("u3msi: failed allocating hwirq\n");
143 return hwirq;
144 }
145
146 addr = find_ht_magic_addr(pdev, hwirq);
147 if (addr == 0)
148 addr = find_u4_magic_addr(pdev, hwirq);
149 msg.address_lo = addr & 0xFFFFFFFF;
150 msg.address_hi = addr >> 32;
151
152 virq = irq_create_mapping(msi_mpic->irqhost, hwirq);
153 if (!virq) {
154 pr_debug("u3msi: failed mapping hwirq 0x%x\n", hwirq);
155 msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, 1);
156 return -ENOSPC;
157 }
158
159 irq_set_msi_desc(virq, entry);
160 irq_set_chip(virq, &mpic_u3msi_chip);
161 irq_set_irq_type(virq, IRQ_TYPE_EDGE_RISING);
162
163 pr_debug("u3msi: allocated virq 0x%x (hw 0x%x) addr 0x%lx\n",
164 virq, hwirq, (unsigned long)addr);
165
166 printk("u3msi: allocated virq 0x%x (hw 0x%x) addr 0x%lx\n",
167 virq, hwirq, (unsigned long)addr);
168 msg.data = hwirq;
169 pci_write_msi_msg(virq, &msg);
170
171 hwirq++;
172 }
173
174 return 0;
175 }
176
mpic_u3msi_init(struct mpic * mpic)177 int mpic_u3msi_init(struct mpic *mpic)
178 {
179 int rc;
180 struct pci_controller *phb;
181
182 rc = mpic_msi_init_allocator(mpic);
183 if (rc) {
184 pr_debug("u3msi: Error allocating bitmap!\n");
185 return rc;
186 }
187
188 pr_debug("u3msi: Registering MPIC U3 MSI callbacks.\n");
189
190 BUG_ON(msi_mpic);
191 msi_mpic = mpic;
192
193 list_for_each_entry(phb, &hose_list, list_node) {
194 WARN_ON(phb->controller_ops.setup_msi_irqs);
195 phb->controller_ops.setup_msi_irqs = u3msi_setup_msi_irqs;
196 phb->controller_ops.teardown_msi_irqs = u3msi_teardown_msi_irqs;
197 }
198
199 return 0;
200 }
201
