2 * MSI framework for platform devices
4 * Copyright (C) 2015 ARM Limited, All Rights Reserved.
5 * Author: Marc Zyngier <marc.zyngier@arm.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
20 #include <linux/device.h>
21 #include <linux/idr.h>
22 #include <linux/irq.h>
23 #include <linux/irqdomain.h>
24 #include <linux/msi.h>
25 #include <linux/slab.h>
27 #define DEV_ID_SHIFT 24
30 * Internal data structure containing a (made up, but unique) devid
31 * and the callback to write the MSI message.
33 struct platform_msi_priv_data {
34 irq_write_msi_msg_t write_msg;
38 /* The devid allocator */
39 static DEFINE_IDA(platform_msi_devid_ida);
41 #ifdef GENERIC_MSI_DOMAIN_OPS
43 * Convert an msi_desc to a globaly unique identifier (per-device
44 * devid + msi_desc position in the msi_list).
46 static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
50 devid = desc->platform.msi_priv_data->devid;
52 return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index;
55 static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
58 arg->hwirq = platform_msi_calc_hwirq(desc);
61 static int platform_msi_init(struct irq_domain *domain,
62 struct msi_domain_info *info,
63 unsigned int virq, irq_hw_number_t hwirq,
64 msi_alloc_info_t *arg)
66 struct irq_data *data;
68 irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
69 info->chip, info->chip_data);
72 * Save the MSI descriptor in handler_data so that the
73 * irq_write_msi_msg callback can retrieve it (and the
76 data = irq_domain_get_irq_data(domain, virq);
77 data->handler_data = arg->desc;
82 #define platform_msi_set_desc NULL
83 #define platform_msi_init NULL
86 static void platform_msi_update_dom_ops(struct msi_domain_info *info)
88 struct msi_domain_ops *ops = info->ops;
92 if (ops->msi_init == NULL)
93 ops->msi_init = platform_msi_init;
94 if (ops->set_desc == NULL)
95 ops->set_desc = platform_msi_set_desc;
98 static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
100 struct msi_desc *desc = irq_data_get_irq_handler_data(data);
101 struct platform_msi_priv_data *priv_data;
103 priv_data = desc->platform.msi_priv_data;
105 priv_data->write_msg(desc, msg);
108 static void platform_msi_update_chip_ops(struct msi_domain_info *info)
110 struct irq_chip *chip = info->chip;
114 chip->irq_mask = irq_chip_mask_parent;
115 if (!chip->irq_unmask)
116 chip->irq_unmask = irq_chip_unmask_parent;
118 chip->irq_eoi = irq_chip_eoi_parent;
119 if (!chip->irq_set_affinity)
120 chip->irq_set_affinity = msi_domain_set_affinity;
121 if (!chip->irq_write_msi_msg)
122 chip->irq_write_msi_msg = platform_msi_write_msg;
125 static void platform_msi_free_descs(struct device *dev)
127 struct msi_desc *desc, *tmp;
129 list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) {
130 list_del(&desc->list);
131 free_msi_entry(desc);
135 static int platform_msi_alloc_descs(struct device *dev, int nvec,
136 struct platform_msi_priv_data *data)
141 for (i = 0; i < nvec; i++) {
142 struct msi_desc *desc;
144 desc = alloc_msi_entry(dev);
148 desc->platform.msi_priv_data = data;
149 desc->platform.msi_index = i;
152 list_add_tail(&desc->list, dev_to_msi_list(dev));
156 /* Clean up the mess */
157 platform_msi_free_descs(dev);
166 * platform_msi_create_irq_domain - Create a platform MSI interrupt domain
167 * @np: Optional device-tree node of the interrupt controller
168 * @info: MSI domain info
169 * @parent: Parent irq domain
171 * Updates the domain and chip ops and creates a platform MSI
175 * A domain pointer or NULL in case of failure.
177 struct irq_domain *platform_msi_create_irq_domain(struct device_node *np,
178 struct msi_domain_info *info,
179 struct irq_domain *parent)
181 struct irq_domain *domain;
183 if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
184 platform_msi_update_dom_ops(info);
185 if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
186 platform_msi_update_chip_ops(info);
188 domain = msi_create_irq_domain(np, info, parent);
190 domain->bus_token = DOMAIN_BUS_PLATFORM_MSI;
196 * platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev
197 * @dev: The device for which to allocate interrupts
198 * @nvec: The number of interrupts to allocate
199 * @write_msi_msg: Callback to write an interrupt message for @dev
202 * Zero for success, or an error code in case of failure
204 int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
205 irq_write_msi_msg_t write_msi_msg)
207 struct platform_msi_priv_data *priv_data;
211 * Limit the number of interrupts to 256 per device. Should we
212 * need to bump this up, DEV_ID_SHIFT should be adjusted
213 * accordingly (which would impact the max number of MSI
216 if (!dev->msi_domain || !write_msi_msg || !nvec ||
217 nvec > (1 << (32 - DEV_ID_SHIFT)))
220 if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) {
221 dev_err(dev, "Incompatible msi_domain, giving up\n");
225 /* Already had a helping of MSI? Greed... */
226 if (!list_empty(dev_to_msi_list(dev)))
229 priv_data = kzalloc(sizeof(*priv_data), GFP_KERNEL);
233 priv_data->devid = ida_simple_get(&platform_msi_devid_ida,
234 0, 1 << DEV_ID_SHIFT, GFP_KERNEL);
235 if (priv_data->devid < 0) {
236 err = priv_data->devid;
240 priv_data->write_msg = write_msi_msg;
242 err = platform_msi_alloc_descs(dev, nvec, priv_data);
246 err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec);
253 platform_msi_free_descs(dev);
255 ida_simple_remove(&platform_msi_devid_ida, priv_data->devid);
263 * platform_msi_domain_free_irqs - Free MSI interrupts for @dev
264 * @dev: The device for which to free interrupts
266 void platform_msi_domain_free_irqs(struct device *dev)
268 struct msi_desc *desc;
270 desc = first_msi_entry(dev);
272 struct platform_msi_priv_data *data;
274 data = desc->platform.msi_priv_data;
276 ida_simple_remove(&platform_msi_devid_ida, data->devid);
280 msi_domain_free_irqs(dev->msi_domain, dev);
281 platform_msi_free_descs(dev);