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![Thomas Gleixner](/assets/img/avatar_default.png)
The allocation code is overly complex. It tries to have the MSI index space packed, which is not working when an interrupt is freed. There is no requirement for this. The only requirement is that the MSI index is unique. Move the MSI descriptor allocation into msi_domain_populate_irqs() and use the Linux interrupt number as MSI index which fulfils the unique requirement. This requires to lock the MSI descriptors which makes the lock order reverse to the regular MSI alloc/free functions vs. the domain mutex. Assign a seperate lockdep class for these MSI device domains. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Nishanth Menon <nm@ti.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20211206210748.956731741@linutronix.de
350 lines
9.7 KiB
C
350 lines
9.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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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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#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 21
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#define MAX_DEV_MSIS (1 << (32 - DEV_ID_SHIFT))
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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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struct device *dev;
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void *host_data;
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msi_alloc_info_t arg;
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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 = desc->dev->msi.data->platform_data->devid;
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return (devid << (32 - DEV_ID_SHIFT)) | desc->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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static void platform_msi_set_proxy_dev(msi_alloc_info_t *arg)
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{
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arg->flags |= MSI_ALLOC_FLAGS_PROXY_DEVICE;
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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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#define platform_msi_set_proxy_dev(x) do {} while(0)
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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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desc->dev->msi.data->platform_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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if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE) &&
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!(chip->flags & IRQCHIP_SUPPORTS_LEVEL_MSI)))
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info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
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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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info->flags |= MSI_FLAG_DEV_SYSFS | MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS |
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MSI_FLAG_FREE_MSI_DESCS;
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domain = msi_create_irq_domain(fwnode, info, parent);
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if (domain)
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irq_domain_update_bus_token(domain, DOMAIN_BUS_PLATFORM_MSI);
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return domain;
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}
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static int platform_msi_alloc_priv_data(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 *datap;
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int err;
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/*
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* Limit the number of interrupts to 2048 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 || nvec > MAX_DEV_MSIS)
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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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err = msi_setup_device_data(dev);
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if (err)
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return err;
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/* Already initialized? */
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if (dev->msi.data->platform_data)
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return -EBUSY;
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datap = kzalloc(sizeof(*datap), GFP_KERNEL);
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if (!datap)
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return -ENOMEM;
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datap->devid = ida_simple_get(&platform_msi_devid_ida,
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0, 1 << DEV_ID_SHIFT, GFP_KERNEL);
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if (datap->devid < 0) {
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err = datap->devid;
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kfree(datap);
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return err;
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}
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datap->write_msg = write_msi_msg;
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datap->dev = dev;
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dev->msi.data->platform_data = datap;
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return 0;
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}
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static void platform_msi_free_priv_data(struct device *dev)
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{
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struct platform_msi_priv_data *data = dev->msi.data->platform_data;
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dev->msi.data->platform_data = NULL;
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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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/**
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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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int err;
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err = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
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if (err)
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return err;
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err = msi_domain_alloc_irqs(dev->msi.domain, dev, nvec);
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if (err)
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platform_msi_free_priv_data(dev);
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return err;
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}
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EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs);
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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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msi_domain_free_irqs(dev->msi.domain, dev);
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platform_msi_free_priv_data(dev);
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}
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EXPORT_SYMBOL_GPL(platform_msi_domain_free_irqs);
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/**
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* platform_msi_get_host_data - Query the private data associated with
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* a platform-msi domain
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* @domain: The platform-msi domain
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*
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* Return: The private data provided when calling
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* platform_msi_create_device_domain().
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*/
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void *platform_msi_get_host_data(struct irq_domain *domain)
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{
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struct platform_msi_priv_data *data = domain->host_data;
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return data->host_data;
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}
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static struct lock_class_key platform_device_msi_lock_class;
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/**
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* __platform_msi_create_device_domain - Create a platform-msi device domain
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*
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* @dev: The device generating the MSIs
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* @nvec: The number of MSIs that need to be allocated
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* @is_tree: flag to indicate tree hierarchy
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* @write_msi_msg: Callback to write an interrupt message for @dev
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* @ops: The hierarchy domain operations to use
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* @host_data: Private data associated to this domain
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*
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* Return: An irqdomain for @nvec interrupts on success, NULL in case of error.
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*
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* This is for interrupt domains which stack on a platform-msi domain
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* created by platform_msi_create_irq_domain(). @dev->msi.domain points to
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* that platform-msi domain which is the parent for the new domain.
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*/
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struct irq_domain *
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__platform_msi_create_device_domain(struct device *dev,
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unsigned int nvec,
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bool is_tree,
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irq_write_msi_msg_t write_msi_msg,
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const struct irq_domain_ops *ops,
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void *host_data)
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{
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struct platform_msi_priv_data *data;
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struct irq_domain *domain;
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int err;
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err = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
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if (err)
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return NULL;
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/*
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* Use a separate lock class for the MSI descriptor mutex on
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* platform MSI device domains because the descriptor mutex nests
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* into the domain mutex. See alloc/free below.
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*/
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lockdep_set_class(&dev->msi.data->mutex, &platform_device_msi_lock_class);
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data = dev->msi.data->platform_data;
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data->host_data = host_data;
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domain = irq_domain_create_hierarchy(dev->msi.domain, 0,
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is_tree ? 0 : nvec,
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dev->fwnode, ops, data);
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if (!domain)
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goto free_priv;
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platform_msi_set_proxy_dev(&data->arg);
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err = msi_domain_prepare_irqs(domain->parent, dev, nvec, &data->arg);
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if (err)
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goto free_domain;
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return domain;
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free_domain:
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irq_domain_remove(domain);
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free_priv:
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platform_msi_free_priv_data(dev);
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return NULL;
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}
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/**
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* platform_msi_device_domain_free - Free interrupts associated with a platform-msi
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* device domain
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*
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* @domain: The platform-msi device domain
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* @virq: The base irq from which to perform the free operation
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* @nr_irqs: How many interrupts to free from @virq
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*/
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void platform_msi_device_domain_free(struct irq_domain *domain, unsigned int virq,
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unsigned int nr_irqs)
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{
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struct platform_msi_priv_data *data = domain->host_data;
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msi_lock_descs(data->dev);
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irq_domain_free_irqs_common(domain, virq, nr_irqs);
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msi_free_msi_descs_range(data->dev, MSI_DESC_ALL, virq, virq + nr_irqs - 1);
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msi_unlock_descs(data->dev);
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}
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/**
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* platform_msi_device_domain_alloc - Allocate interrupts associated with
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* a platform-msi device domain
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*
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* @domain: The platform-msi device domain
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* @virq: The base irq from which to perform the allocate operation
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* @nr_irqs: How many interrupts to allocate from @virq
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*
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* Return 0 on success, or an error code on failure. Must be called
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* with irq_domain_mutex held (which can only be done as part of a
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* top-level interrupt allocation).
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*/
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int platform_msi_device_domain_alloc(struct irq_domain *domain, unsigned int virq,
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unsigned int nr_irqs)
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{
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struct platform_msi_priv_data *data = domain->host_data;
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struct device *dev = data->dev;
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return msi_domain_populate_irqs(domain->parent, dev, virq, nr_irqs, &data->arg);
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}
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