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
28 #define MAX_DEV_MSIS (1 << (32 - DEV_ID_SHIFT))
31 * Internal data structure containing a (made up, but unique) devid
32 * and the callback to write the MSI message.
34 struct platform_msi_priv_data {
35 irq_write_msi_msg_t write_msg;
39 /* The devid allocator */
40 static DEFINE_IDA(platform_msi_devid_ida);
42 #ifdef GENERIC_MSI_DOMAIN_OPS
44 * Convert an msi_desc to a globaly unique identifier (per-device
45 * devid + msi_desc position in the msi_list).
47 static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
51 devid = desc->platform.msi_priv_data->devid;
53 return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index;
56 static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
59 arg->hwirq = platform_msi_calc_hwirq(desc);
62 static int platform_msi_init(struct irq_domain *domain,
63 struct msi_domain_info *info,
64 unsigned int virq, irq_hw_number_t hwirq,
65 msi_alloc_info_t *arg)
67 return irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
68 info->chip, info->chip_data);
71 #define platform_msi_set_desc NULL
72 #define platform_msi_init NULL
75 static void platform_msi_update_dom_ops(struct msi_domain_info *info)
77 struct msi_domain_ops *ops = info->ops;
81 if (ops->msi_init == NULL)
82 ops->msi_init = platform_msi_init;
83 if (ops->set_desc == NULL)
84 ops->set_desc = platform_msi_set_desc;
87 static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
89 struct msi_desc *desc = irq_data_get_msi_desc(data);
90 struct platform_msi_priv_data *priv_data;
92 priv_data = desc->platform.msi_priv_data;
94 priv_data->write_msg(desc, msg);
97 static void platform_msi_update_chip_ops(struct msi_domain_info *info)
99 struct irq_chip *chip = info->chip;
103 chip->irq_mask = irq_chip_mask_parent;
104 if (!chip->irq_unmask)
105 chip->irq_unmask = irq_chip_unmask_parent;
107 chip->irq_eoi = irq_chip_eoi_parent;
108 if (!chip->irq_set_affinity)
109 chip->irq_set_affinity = msi_domain_set_affinity;
110 if (!chip->irq_write_msi_msg)
111 chip->irq_write_msi_msg = platform_msi_write_msg;
114 static void platform_msi_free_descs(struct device *dev, int base, int nvec)
116 struct msi_desc *desc, *tmp;
118 list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) {
119 if (desc->platform.msi_index >= base &&
120 desc->platform.msi_index < (base + nvec)) {
121 list_del(&desc->list);
122 free_msi_entry(desc);
127 static int platform_msi_alloc_descs(struct device *dev, int nvec,
128 struct platform_msi_priv_data *data)
131 struct msi_desc *desc;
134 if (!list_empty(dev_to_msi_list(dev))) {
135 desc = list_last_entry(dev_to_msi_list(dev),
136 struct msi_desc, list);
137 base = desc->platform.msi_index + 1;
140 for (i = 0; i < nvec; i++) {
141 desc = alloc_msi_entry(dev);
145 desc->platform.msi_priv_data = data;
146 desc->platform.msi_index = base + i;
149 list_add_tail(&desc->list, dev_to_msi_list(dev));
153 /* Clean up the mess */
154 platform_msi_free_descs(dev, base, nvec);
163 * platform_msi_create_irq_domain - Create a platform MSI interrupt domain
164 * @fwnode: Optional fwnode of the interrupt controller
165 * @info: MSI domain info
166 * @parent: Parent irq domain
168 * Updates the domain and chip ops and creates a platform MSI
172 * A domain pointer or NULL in case of failure.
174 struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode,
175 struct msi_domain_info *info,
176 struct irq_domain *parent)
178 struct irq_domain *domain;
180 if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
181 platform_msi_update_dom_ops(info);
182 if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
183 platform_msi_update_chip_ops(info);
185 domain = msi_create_irq_domain(fwnode, info, parent);
187 domain->bus_token = DOMAIN_BUS_PLATFORM_MSI;
192 static struct platform_msi_priv_data *
193 platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec,
194 irq_write_msi_msg_t write_msi_msg)
196 struct platform_msi_priv_data *datap;
198 * Limit the number of interrupts to 256 per device. Should we
199 * need to bump this up, DEV_ID_SHIFT should be adjusted
200 * accordingly (which would impact the max number of MSI
203 if (!dev->msi_domain || !write_msi_msg || !nvec || nvec > MAX_DEV_MSIS)
204 return ERR_PTR(-EINVAL);
206 if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) {
207 dev_err(dev, "Incompatible msi_domain, giving up\n");
208 return ERR_PTR(-EINVAL);
211 /* Already had a helping of MSI? Greed... */
212 if (!list_empty(dev_to_msi_list(dev)))
213 return ERR_PTR(-EBUSY);
215 datap = kzalloc(sizeof(*datap), GFP_KERNEL);
217 return ERR_PTR(-ENOMEM);
219 datap->devid = ida_simple_get(&platform_msi_devid_ida,
220 0, 1 << DEV_ID_SHIFT, GFP_KERNEL);
221 if (datap->devid < 0) {
222 int err = datap->devid;
227 datap->write_msg = write_msi_msg;
232 static void platform_msi_free_priv_data(struct platform_msi_priv_data *data)
234 ida_simple_remove(&platform_msi_devid_ida, data->devid);
239 * platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev
240 * @dev: The device for which to allocate interrupts
241 * @nvec: The number of interrupts to allocate
242 * @write_msi_msg: Callback to write an interrupt message for @dev
245 * Zero for success, or an error code in case of failure
247 int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
248 irq_write_msi_msg_t write_msi_msg)
250 struct platform_msi_priv_data *priv_data;
253 priv_data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
254 if (IS_ERR(priv_data))
255 return PTR_ERR(priv_data);
257 err = platform_msi_alloc_descs(dev, nvec, priv_data);
259 goto out_free_priv_data;
261 err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec);
268 platform_msi_free_descs(dev, 0, nvec);
270 platform_msi_free_priv_data(priv_data);
276 * platform_msi_domain_free_irqs - Free MSI interrupts for @dev
277 * @dev: The device for which to free interrupts
279 void platform_msi_domain_free_irqs(struct device *dev)
281 if (!list_empty(dev_to_msi_list(dev))) {
282 struct msi_desc *desc;
284 desc = first_msi_entry(dev);
285 platform_msi_free_priv_data(desc->platform.msi_priv_data);
288 msi_domain_free_irqs(dev->msi_domain, dev);
289 platform_msi_free_descs(dev, 0, MAX_DEV_MSIS);