1/*
2 * Copyright 2006, Segher Boessenkool, IBM Corporation.
3 * Copyright 2006-2007, Michael Ellerman, IBM Corporation.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; version 2 of the
8 * License.
9 *
10 */
11
12#include <linux/irq.h>
13#include <linux/msi.h>
14#include <asm/mpic.h>
15#include <asm/prom.h>
16#include <asm/hw_irq.h>
17#include <asm/ppc-pci.h>
18#include <asm/msi_bitmap.h>
19
20#include "mpic.h"
21
22/* A bit ugly, can we get this from the pci_dev somehow? */
23static struct mpic *msi_mpic;
24
25static void mpic_u3msi_mask_irq(struct irq_data *data)
26{
27	pci_msi_mask_irq(data);
28	mpic_mask_irq(data);
29}
30
31static void mpic_u3msi_unmask_irq(struct irq_data *data)
32{
33	mpic_unmask_irq(data);
34	pci_msi_unmask_irq(data);
35}
36
37static struct irq_chip mpic_u3msi_chip = {
38	.irq_shutdown		= mpic_u3msi_mask_irq,
39	.irq_mask		= mpic_u3msi_mask_irq,
40	.irq_unmask		= mpic_u3msi_unmask_irq,
41	.irq_eoi		= mpic_end_irq,
42	.irq_set_type		= mpic_set_irq_type,
43	.irq_set_affinity	= mpic_set_affinity,
44	.name			= "MPIC-U3MSI",
45};
46
47static u64 read_ht_magic_addr(struct pci_dev *pdev, unsigned int pos)
48{
49	u8 flags;
50	u32 tmp;
51	u64 addr;
52
53	pci_read_config_byte(pdev, pos + HT_MSI_FLAGS, &flags);
54
55	if (flags & HT_MSI_FLAGS_FIXED)
56		return HT_MSI_FIXED_ADDR;
57
58	pci_read_config_dword(pdev, pos + HT_MSI_ADDR_LO, &tmp);
59	addr = tmp & HT_MSI_ADDR_LO_MASK;
60	pci_read_config_dword(pdev, pos + HT_MSI_ADDR_HI, &tmp);
61	addr = addr | ((u64)tmp << 32);
62
63	return addr;
64}
65
66static u64 find_ht_magic_addr(struct pci_dev *pdev, unsigned int hwirq)
67{
68	struct pci_bus *bus;
69	unsigned int pos;
70
71	for (bus = pdev->bus; bus && bus->self; bus = bus->parent) {
72		pos = pci_find_ht_capability(bus->self, HT_CAPTYPE_MSI_MAPPING);
73		if (pos)
74			return read_ht_magic_addr(bus->self, pos);
75	}
76
77	return 0;
78}
79
80static u64 find_u4_magic_addr(struct pci_dev *pdev, unsigned int hwirq)
81{
82	struct pci_controller *hose = pci_bus_to_host(pdev->bus);
83
84	/* U4 PCIe MSIs need to write to the special register in
85	 * the bridge that generates interrupts. There should be
86	 * theorically a register at 0xf8005000 where you just write
87	 * the MSI number and that triggers the right interrupt, but
88	 * unfortunately, this is busted in HW, the bridge endian swaps
89	 * the value and hits the wrong nibble in the register.
90	 *
91	 * So instead we use another register set which is used normally
92	 * for converting HT interrupts to MPIC interrupts, which decodes
93	 * the interrupt number as part of the low address bits
94	 *
95	 * This will not work if we ever use more than one legacy MSI in
96	 * a block but we never do. For one MSI or multiple MSI-X where
97	 * each interrupt address can be specified separately, it works
98	 * just fine.
99	 */
100	if (of_device_is_compatible(hose->dn, "u4-pcie") ||
101	    of_device_is_compatible(hose->dn, "U4-pcie"))
102		return 0xf8004000 | (hwirq << 4);
103
104	return 0;
105}
106
107static void u3msi_teardown_msi_irqs(struct pci_dev *pdev)
108{
109	struct msi_desc *entry;
110	irq_hw_number_t hwirq;
111
112        list_for_each_entry(entry, &pdev->msi_list, list) {
113		if (entry->irq == NO_IRQ)
114			continue;
115
116		hwirq = virq_to_hw(entry->irq);
117		irq_set_msi_desc(entry->irq, NULL);
118		irq_dispose_mapping(entry->irq);
119		msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, 1);
120	}
121
122	return;
123}
124
125static int u3msi_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
126{
127	unsigned int virq;
128	struct msi_desc *entry;
129	struct msi_msg msg;
130	u64 addr;
131	int hwirq;
132
133	if (type == PCI_CAP_ID_MSIX)
134		pr_debug("u3msi: MSI-X untested, trying anyway.\n");
135
136	/* If we can't find a magic address then MSI ain't gonna work */
137	if (find_ht_magic_addr(pdev, 0) == 0 &&
138	    find_u4_magic_addr(pdev, 0) == 0) {
139		pr_debug("u3msi: no magic address found for %s\n",
140			 pci_name(pdev));
141		return -ENXIO;
142	}
143
144	list_for_each_entry(entry, &pdev->msi_list, list) {
145		hwirq = msi_bitmap_alloc_hwirqs(&msi_mpic->msi_bitmap, 1);
146		if (hwirq < 0) {
147			pr_debug("u3msi: failed allocating hwirq\n");
148			return hwirq;
149		}
150
151		addr = find_ht_magic_addr(pdev, hwirq);
152		if (addr == 0)
153			addr = find_u4_magic_addr(pdev, hwirq);
154		msg.address_lo = addr & 0xFFFFFFFF;
155		msg.address_hi = addr >> 32;
156
157		virq = irq_create_mapping(msi_mpic->irqhost, hwirq);
158		if (virq == NO_IRQ) {
159			pr_debug("u3msi: failed mapping hwirq 0x%x\n", hwirq);
160			msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, 1);
161			return -ENOSPC;
162		}
163
164		irq_set_msi_desc(virq, entry);
165		irq_set_chip(virq, &mpic_u3msi_chip);
166		irq_set_irq_type(virq, IRQ_TYPE_EDGE_RISING);
167
168		pr_debug("u3msi: allocated virq 0x%x (hw 0x%x) addr 0x%lx\n",
169			  virq, hwirq, (unsigned long)addr);
170
171		printk("u3msi: allocated virq 0x%x (hw 0x%x) addr 0x%lx\n",
172			  virq, hwirq, (unsigned long)addr);
173		msg.data = hwirq;
174		pci_write_msi_msg(virq, &msg);
175
176		hwirq++;
177	}
178
179	return 0;
180}
181
182int mpic_u3msi_init(struct mpic *mpic)
183{
184	int rc;
185
186	rc = mpic_msi_init_allocator(mpic);
187	if (rc) {
188		pr_debug("u3msi: Error allocating bitmap!\n");
189		return rc;
190	}
191
192	pr_debug("u3msi: Registering MPIC U3 MSI callbacks.\n");
193
194	BUG_ON(msi_mpic);
195	msi_mpic = mpic;
196
197	WARN_ON(ppc_md.setup_msi_irqs);
198	ppc_md.setup_msi_irqs = u3msi_setup_msi_irqs;
199	ppc_md.teardown_msi_irqs = u3msi_teardown_msi_irqs;
200
201	return 0;
202}
203