271 lines
6.7 KiB
C
271 lines
6.7 KiB
C
/*
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* MSI framework for platform devices
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*
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* Copyright (C) 2015 ARM Limited, All Rights Reserved.
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* Author: Marc Zyngier <marc.zyngier@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/device.h>
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#include <linux/idr.h>
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#include <linux/irq.h>
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#include <linux/irqdomain.h>
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#include <linux/msi.h>
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#include <linux/slab.h>
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#define DEV_ID_SHIFT 24
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/*
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* Internal data structure containing a (made up, but unique) devid
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* and the callback to write the MSI message.
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*/
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struct platform_msi_priv_data {
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irq_write_msi_msg_t write_msg;
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int devid;
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};
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/* The devid allocator */
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static DEFINE_IDA(platform_msi_devid_ida);
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#ifdef GENERIC_MSI_DOMAIN_OPS
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/*
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* Convert an msi_desc to a globaly unique identifier (per-device
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* devid + msi_desc position in the msi_list).
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*/
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static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
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{
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u32 devid;
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devid = desc->platform.msi_priv_data->devid;
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return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index;
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}
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static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
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{
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arg->desc = desc;
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arg->hwirq = platform_msi_calc_hwirq(desc);
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}
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static int platform_msi_init(struct irq_domain *domain,
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struct msi_domain_info *info,
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unsigned int virq, irq_hw_number_t hwirq,
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msi_alloc_info_t *arg)
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{
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return irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
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info->chip, info->chip_data);
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}
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#else
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#define platform_msi_set_desc NULL
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#define platform_msi_init NULL
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#endif
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static void platform_msi_update_dom_ops(struct msi_domain_info *info)
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{
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struct msi_domain_ops *ops = info->ops;
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BUG_ON(!ops);
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if (ops->msi_init == NULL)
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ops->msi_init = platform_msi_init;
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if (ops->set_desc == NULL)
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ops->set_desc = platform_msi_set_desc;
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}
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static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
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{
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struct msi_desc *desc = irq_data_get_msi_desc(data);
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struct platform_msi_priv_data *priv_data;
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priv_data = desc->platform.msi_priv_data;
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priv_data->write_msg(desc, msg);
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}
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static void platform_msi_update_chip_ops(struct msi_domain_info *info)
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{
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struct irq_chip *chip = info->chip;
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BUG_ON(!chip);
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if (!chip->irq_mask)
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chip->irq_mask = irq_chip_mask_parent;
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if (!chip->irq_unmask)
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chip->irq_unmask = irq_chip_unmask_parent;
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if (!chip->irq_eoi)
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chip->irq_eoi = irq_chip_eoi_parent;
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if (!chip->irq_set_affinity)
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chip->irq_set_affinity = msi_domain_set_affinity;
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if (!chip->irq_write_msi_msg)
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chip->irq_write_msi_msg = platform_msi_write_msg;
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}
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static void platform_msi_free_descs(struct device *dev)
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{
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struct msi_desc *desc, *tmp;
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list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) {
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list_del(&desc->list);
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free_msi_entry(desc);
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}
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}
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static int platform_msi_alloc_descs(struct device *dev, int nvec,
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struct platform_msi_priv_data *data)
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{
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int i;
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for (i = 0; i < nvec; i++) {
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struct msi_desc *desc;
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desc = alloc_msi_entry(dev);
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if (!desc)
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break;
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desc->platform.msi_priv_data = data;
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desc->platform.msi_index = i;
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desc->nvec_used = 1;
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list_add_tail(&desc->list, dev_to_msi_list(dev));
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}
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if (i != nvec) {
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/* Clean up the mess */
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platform_msi_free_descs(dev);
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return -ENOMEM;
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}
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return 0;
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}
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/**
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* platform_msi_create_irq_domain - Create a platform MSI interrupt domain
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* @fwnode: Optional fwnode of the interrupt controller
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* @info: MSI domain info
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* @parent: Parent irq domain
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*
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* Updates the domain and chip ops and creates a platform MSI
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* interrupt domain.
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*
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* Returns:
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* A domain pointer or NULL in case of failure.
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*/
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struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode,
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struct msi_domain_info *info,
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struct irq_domain *parent)
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{
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struct irq_domain *domain;
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if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
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platform_msi_update_dom_ops(info);
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if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
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platform_msi_update_chip_ops(info);
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domain = msi_create_irq_domain(fwnode, info, parent);
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if (domain)
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domain->bus_token = DOMAIN_BUS_PLATFORM_MSI;
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return domain;
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}
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/**
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* platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev
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* @dev: The device for which to allocate interrupts
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* @nvec: The number of interrupts to allocate
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* @write_msi_msg: Callback to write an interrupt message for @dev
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*
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* Returns:
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* Zero for success, or an error code in case of failure
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*/
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int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
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irq_write_msi_msg_t write_msi_msg)
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{
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struct platform_msi_priv_data *priv_data;
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int err;
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/*
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* Limit the number of interrupts to 256 per device. Should we
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* need to bump this up, DEV_ID_SHIFT should be adjusted
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* accordingly (which would impact the max number of MSI
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* capable devices).
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*/
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if (!dev->msi_domain || !write_msi_msg || !nvec ||
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nvec > (1 << (32 - DEV_ID_SHIFT)))
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return -EINVAL;
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if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) {
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dev_err(dev, "Incompatible msi_domain, giving up\n");
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return -EINVAL;
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}
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/* Already had a helping of MSI? Greed... */
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if (!list_empty(dev_to_msi_list(dev)))
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return -EBUSY;
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priv_data = kzalloc(sizeof(*priv_data), GFP_KERNEL);
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if (!priv_data)
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return -ENOMEM;
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priv_data->devid = ida_simple_get(&platform_msi_devid_ida,
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0, 1 << DEV_ID_SHIFT, GFP_KERNEL);
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if (priv_data->devid < 0) {
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err = priv_data->devid;
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goto out_free_data;
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}
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priv_data->write_msg = write_msi_msg;
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err = platform_msi_alloc_descs(dev, nvec, priv_data);
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if (err)
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goto out_free_id;
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err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec);
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if (err)
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goto out_free_desc;
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return 0;
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out_free_desc:
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platform_msi_free_descs(dev);
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out_free_id:
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ida_simple_remove(&platform_msi_devid_ida, priv_data->devid);
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out_free_data:
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kfree(priv_data);
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return err;
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}
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/**
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* platform_msi_domain_free_irqs - Free MSI interrupts for @dev
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* @dev: The device for which to free interrupts
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*/
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void platform_msi_domain_free_irqs(struct device *dev)
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{
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struct msi_desc *desc;
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desc = first_msi_entry(dev);
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if (desc) {
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struct platform_msi_priv_data *data;
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data = desc->platform.msi_priv_data;
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ida_simple_remove(&platform_msi_devid_ida, data->devid);
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kfree(data);
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}
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msi_domain_free_irqs(dev->msi_domain, dev);
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platform_msi_free_descs(dev);
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}
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