1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * MSI support for PPC4xx SoCs using High Speed Transfer Assist (HSTA) for
4 * generation of the interrupt.
5 *
6 * Copyright �� 2013 Alistair Popple <alistair@popple.id.au> IBM Corporation
7 */
8
9#include <linux/kernel.h>
10#include <linux/interrupt.h>
11#include <linux/msi.h>
12#include <linux/of.h>
13#include <linux/of_irq.h>
14#include <linux/platform_device.h>
15#include <linux/pci.h>
16#include <linux/semaphore.h>
17#include <asm/msi_bitmap.h>
18#include <asm/ppc-pci.h>
19
20struct ppc4xx_hsta_msi {
21	struct device *dev;
22
23	/* The ioremapped HSTA MSI IO space */
24	u32 __iomem *data;
25
26	/* Physical address of HSTA MSI IO space */
27	u64 address;
28	struct msi_bitmap bmp;
29
30	/* An array mapping offsets to hardware IRQs */
31	int *irq_map;
32
33	/* Number of hwirqs supported */
34	int irq_count;
35};
36static struct ppc4xx_hsta_msi ppc4xx_hsta_msi;
37
38static int hsta_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
39{
40	struct msi_msg msg;
41	struct msi_desc *entry;
42	int irq, hwirq;
43	u64 addr;
44
45	/* We don't support MSI-X */
46	if (type == PCI_CAP_ID_MSIX) {
47		pr_debug("%s: MSI-X not supported.\n", __func__);
48		return -EINVAL;
49	}
50
51	msi_for_each_desc(entry, &dev->dev, MSI_DESC_NOTASSOCIATED) {
52		irq = msi_bitmap_alloc_hwirqs(&ppc4xx_hsta_msi.bmp, 1);
53		if (irq < 0) {
54			pr_debug("%s: Failed to allocate msi interrupt\n",
55				 __func__);
56			return irq;
57		}
58
59		hwirq = ppc4xx_hsta_msi.irq_map[irq];
60		if (!hwirq) {
61			pr_err("%s: Failed mapping irq %d\n", __func__, irq);
62			return -EINVAL;
63		}
64
65		/*
66		 * HSTA generates interrupts on writes to 128-bit aligned
67		 * addresses.
68		 */
69		addr = ppc4xx_hsta_msi.address + irq*0x10;
70		msg.address_hi = upper_32_bits(addr);
71		msg.address_lo = lower_32_bits(addr);
72
73		/* Data is not used by the HSTA. */
74		msg.data = 0;
75
76		pr_debug("%s: Setup irq %d (0x%0llx)\n", __func__, hwirq,
77			 (((u64) msg.address_hi) << 32) | msg.address_lo);
78
79		if (irq_set_msi_desc(hwirq, entry)) {
80			pr_err(
81			"%s: Invalid hwirq %d specified in device tree\n",
82			__func__, hwirq);
83			msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
84			return -EINVAL;
85		}
86		pci_write_msi_msg(hwirq, &msg);
87	}
88
89	return 0;
90}
91
92static int hsta_find_hwirq_offset(int hwirq)
93{
94	int irq;
95
96	/* Find the offset given the hwirq */
97	for (irq = 0; irq < ppc4xx_hsta_msi.irq_count; irq++)
98		if (ppc4xx_hsta_msi.irq_map[irq] == hwirq)
99			return irq;
100
101	return -EINVAL;
102}
103
104static void hsta_teardown_msi_irqs(struct pci_dev *dev)
105{
106	struct msi_desc *entry;
107	int irq;
108
109	msi_for_each_desc(entry, &dev->dev, MSI_DESC_ASSOCIATED) {
110		irq = hsta_find_hwirq_offset(entry->irq);
111
112		/* entry->irq should always be in irq_map */
113		BUG_ON(irq < 0);
114		irq_set_msi_desc(entry->irq, NULL);
115		msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
116		pr_debug("%s: Teardown IRQ %u (index %u)\n", __func__,
117			 entry->irq, irq);
118		entry->irq = 0;
119	}
120}
121
122static int hsta_msi_probe(struct platform_device *pdev)
123{
124	struct device *dev = &pdev->dev;
125	struct resource *mem;
126	int irq, ret, irq_count;
127	struct pci_controller *phb;
128
129	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
130	if (!mem) {
131		dev_err(dev, "Unable to get mmio space\n");
132		return -EINVAL;
133	}
134
135	irq_count = of_irq_count(dev->of_node);
136	if (!irq_count) {
137		dev_err(dev, "Unable to find IRQ range\n");
138		return -EINVAL;
139	}
140
141	ppc4xx_hsta_msi.dev = dev;
142	ppc4xx_hsta_msi.address = mem->start;
143	ppc4xx_hsta_msi.data = ioremap(mem->start, resource_size(mem));
144	ppc4xx_hsta_msi.irq_count = irq_count;
145	if (!ppc4xx_hsta_msi.data) {
146		dev_err(dev, "Unable to map memory\n");
147		return -ENOMEM;
148	}
149
150	ret = msi_bitmap_alloc(&ppc4xx_hsta_msi.bmp, irq_count, dev->of_node);
151	if (ret)
152		goto out;
153
154	ppc4xx_hsta_msi.irq_map = kmalloc_array(irq_count, sizeof(int),
155						GFP_KERNEL);
156	if (!ppc4xx_hsta_msi.irq_map) {
157		ret = -ENOMEM;
158		goto out1;
159	}
160
161	/* Setup a mapping from irq offsets to hardware irq numbers */
162	for (irq = 0; irq < irq_count; irq++) {
163		ppc4xx_hsta_msi.irq_map[irq] =
164			irq_of_parse_and_map(dev->of_node, irq);
165		if (!ppc4xx_hsta_msi.irq_map[irq]) {
166			dev_err(dev, "Unable to map IRQ\n");
167			ret = -EINVAL;
168			goto out2;
169		}
170	}
171
172	list_for_each_entry(phb, &hose_list, list_node) {
173		phb->controller_ops.setup_msi_irqs = hsta_setup_msi_irqs;
174		phb->controller_ops.teardown_msi_irqs = hsta_teardown_msi_irqs;
175	}
176	return 0;
177
178out2:
179	kfree(ppc4xx_hsta_msi.irq_map);
180
181out1:
182	msi_bitmap_free(&ppc4xx_hsta_msi.bmp);
183
184out:
185	iounmap(ppc4xx_hsta_msi.data);
186	return ret;
187}
188
189static const struct of_device_id hsta_msi_ids[] = {
190	{
191		.compatible = "ibm,hsta-msi",
192	},
193	{}
194};
195
196static struct platform_driver hsta_msi_driver = {
197	.probe = hsta_msi_probe,
198	.driver = {
199		.name = "hsta-msi",
200		.of_match_table = hsta_msi_ids,
201	},
202};
203
204static int hsta_msi_init(void)
205{
206	return platform_driver_register(&hsta_msi_driver);
207}
208subsys_initcall(hsta_msi_init);
209