1// SPDX-License-Identifier: GPL-2.0
2/*
3 * AMD CDX bus driver MSI support
4 *
5 * Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
6 */
7
8#include <linux/of.h>
9#include <linux/of_device.h>
10#include <linux/of_address.h>
11#include <linux/of_irq.h>
12#include <linux/irq.h>
13#include <linux/irqdomain.h>
14#include <linux/msi.h>
15#include <linux/cdx/cdx_bus.h>
16
17#include "cdx.h"
18
19static void cdx_msi_write_msg(struct irq_data *irq_data, struct msi_msg *msg)
20{
21	struct msi_desc *msi_desc = irq_data_get_msi_desc(irq_data);
22	struct cdx_device *cdx_dev = to_cdx_device(msi_desc->dev);
23
24	/* We would not operate on msg here rather we wait for irq_bus_sync_unlock()
25	 * to be called from preemptible task context.
26	 */
27	msi_desc->msg = *msg;
28	cdx_dev->msi_write_pending = true;
29}
30
31static void cdx_msi_write_irq_lock(struct irq_data *irq_data)
32{
33	struct msi_desc *msi_desc = irq_data_get_msi_desc(irq_data);
34	struct cdx_device *cdx_dev = to_cdx_device(msi_desc->dev);
35
36	mutex_lock(&cdx_dev->irqchip_lock);
37}
38
39static void cdx_msi_write_irq_unlock(struct irq_data *irq_data)
40{
41	struct msi_desc *msi_desc = irq_data_get_msi_desc(irq_data);
42	struct cdx_device *cdx_dev = to_cdx_device(msi_desc->dev);
43	struct cdx_controller *cdx = cdx_dev->cdx;
44	struct cdx_device_config dev_config;
45
46	if (!cdx_dev->msi_write_pending) {
47		mutex_unlock(&cdx_dev->irqchip_lock);
48		return;
49	}
50
51	cdx_dev->msi_write_pending = false;
52	mutex_unlock(&cdx_dev->irqchip_lock);
53
54	dev_config.msi.msi_index = msi_desc->msi_index;
55	dev_config.msi.data = msi_desc->msg.data;
56	dev_config.msi.addr = ((u64)(msi_desc->msg.address_hi) << 32) | msi_desc->msg.address_lo;
57
58	/*
59	 * dev_configure() is a controller callback which can interact with
60	 * Firmware or other entities, and can sleep, so invoke this function
61	 * outside of the mutex held region.
62	 */
63	dev_config.type = CDX_DEV_MSI_CONF;
64	if (cdx->ops->dev_configure)
65		cdx->ops->dev_configure(cdx, cdx_dev->bus_num, cdx_dev->dev_num, &dev_config);
66}
67
68int cdx_enable_msi(struct cdx_device *cdx_dev)
69{
70	struct cdx_controller *cdx = cdx_dev->cdx;
71	struct cdx_device_config dev_config;
72
73	dev_config.type = CDX_DEV_MSI_ENABLE;
74	dev_config.msi_enable = true;
75	if (cdx->ops->dev_configure) {
76		return cdx->ops->dev_configure(cdx, cdx_dev->bus_num, cdx_dev->dev_num,
77					       &dev_config);
78	}
79
80	return -EOPNOTSUPP;
81}
82EXPORT_SYMBOL_GPL(cdx_enable_msi);
83
84void cdx_disable_msi(struct cdx_device *cdx_dev)
85{
86	struct cdx_controller *cdx = cdx_dev->cdx;
87	struct cdx_device_config dev_config;
88
89	dev_config.type = CDX_DEV_MSI_ENABLE;
90	dev_config.msi_enable = false;
91	if (cdx->ops->dev_configure)
92		cdx->ops->dev_configure(cdx, cdx_dev->bus_num, cdx_dev->dev_num, &dev_config);
93}
94EXPORT_SYMBOL_GPL(cdx_disable_msi);
95
96static struct irq_chip cdx_msi_irq_chip = {
97	.name			= "CDX-MSI",
98	.irq_mask		= irq_chip_mask_parent,
99	.irq_unmask		= irq_chip_unmask_parent,
100	.irq_eoi		= irq_chip_eoi_parent,
101	.irq_set_affinity	= msi_domain_set_affinity,
102	.irq_write_msi_msg	= cdx_msi_write_msg,
103	.irq_bus_lock		= cdx_msi_write_irq_lock,
104	.irq_bus_sync_unlock	= cdx_msi_write_irq_unlock
105};
106
107/* Convert an msi_desc to a unique identifier within the domain. */
108static irq_hw_number_t cdx_domain_calc_hwirq(struct cdx_device *dev,
109					     struct msi_desc *desc)
110{
111	return ((irq_hw_number_t)dev->msi_dev_id << 10) | desc->msi_index;
112}
113
114static void cdx_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
115{
116	arg->desc = desc;
117	arg->hwirq = cdx_domain_calc_hwirq(to_cdx_device(desc->dev), desc);
118}
119
120static int cdx_msi_prepare(struct irq_domain *msi_domain,
121			   struct device *dev,
122			   int nvec, msi_alloc_info_t *info)
123{
124	struct cdx_device *cdx_dev = to_cdx_device(dev);
125	struct device *parent = cdx_dev->cdx->dev;
126	struct msi_domain_info *msi_info;
127	u32 dev_id;
128	int ret;
129
130	/* Retrieve device ID from requestor ID using parent device */
131	ret = of_map_id(parent->of_node, cdx_dev->msi_dev_id, "msi-map", "msi-map-mask",
132			NULL, &dev_id);
133	if (ret) {
134		dev_err(dev, "of_map_id failed for MSI: %d\n", ret);
135		return ret;
136	}
137
138#ifdef GENERIC_MSI_DOMAIN_OPS
139	/* Set the device Id to be passed to the GIC-ITS */
140	info->scratchpad[0].ul = dev_id;
141#endif
142
143	msi_info = msi_get_domain_info(msi_domain->parent);
144
145	return msi_info->ops->msi_prepare(msi_domain->parent, dev, nvec, info);
146}
147
148static struct msi_domain_ops cdx_msi_ops = {
149	.msi_prepare	= cdx_msi_prepare,
150	.set_desc	= cdx_msi_set_desc
151};
152
153static struct msi_domain_info cdx_msi_domain_info = {
154	.ops	= &cdx_msi_ops,
155	.chip	= &cdx_msi_irq_chip,
156	.flags	= MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
157		  MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS | MSI_FLAG_FREE_MSI_DESCS
158};
159
160struct irq_domain *cdx_msi_domain_init(struct device *dev)
161{
162	struct device_node *np = dev->of_node;
163	struct fwnode_handle *fwnode_handle;
164	struct irq_domain *cdx_msi_domain;
165	struct device_node *parent_node;
166	struct irq_domain *parent;
167
168	fwnode_handle = of_node_to_fwnode(np);
169
170	parent_node = of_parse_phandle(np, "msi-map", 1);
171	if (!parent_node) {
172		dev_err(dev, "msi-map not present on cdx controller\n");
173		return NULL;
174	}
175
176	parent = irq_find_matching_fwnode(of_node_to_fwnode(parent_node), DOMAIN_BUS_NEXUS);
177	if (!parent || !msi_get_domain_info(parent)) {
178		dev_err(dev, "unable to locate ITS domain\n");
179		return NULL;
180	}
181
182	cdx_msi_domain = msi_create_irq_domain(fwnode_handle, &cdx_msi_domain_info, parent);
183	if (!cdx_msi_domain) {
184		dev_err(dev, "unable to create CDX-MSI domain\n");
185		return NULL;
186	}
187
188	dev_dbg(dev, "CDX-MSI domain created\n");
189
190	return cdx_msi_domain;
191}
192EXPORT_SYMBOL_NS_GPL(cdx_msi_domain_init, CDX_BUS_CONTROLLER);
193