drivers/base/platform-msi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * MSI framework for platform devices
   4  *
   5  * Copyright (C) 2015 ARM Limited, All Rights Reserved.
   6  * Author: Marc Zyngier <marc.zyngier@arm.com>
   7  * Copyright (C) 2022 Linutronix GmbH
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/irqdomain.h>
  12 #include <linux/msi.h>
  13
  14 /*
  15  * This indirection can go when platform_device_msi_init_and_alloc_irqs()
  16  * is switched to a proper irq_chip::irq_write_msi_msg() callback. Keep it
  17  * simple for now.
  18  */
  19 static void platform_msi_write_msi_msg(struct irq_data *d, struct msi_msg *msg)
  20 {
  21         irq_write_msi_msg_t cb = d->chip_data;
  22
  23         cb(irq_data_get_msi_desc(d), msg);
  24 }
  25
  26 static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
  27 {
  28         arg->desc = desc;
  29         arg->hwirq = desc->msi_index;
  30 }
  31
  32 static const struct msi_domain_template platform_msi_template = {
  33         .chip = {
  34                 .name                   = "pMSI",
  35                 .irq_mask               = irq_chip_mask_parent,
  36                 .irq_unmask             = irq_chip_unmask_parent,
  37                 .irq_write_msi_msg      = platform_msi_write_msi_msg,
  38                 /* The rest is filled in by the platform MSI parent */
  39         },
  40
  41         .ops = {
  42                 .set_desc               = platform_msi_set_desc,
  43         },
  44
  45         .info = {
  46                 .bus_token              = DOMAIN_BUS_DEVICE_MSI,
  47         },
  48 };
  49
  50 /**
  51  * platform_device_msi_init_and_alloc_irqs - Initialize platform device MSI
  52  *                                           and allocate interrupts for @dev
  53  * @dev:                The device for which to allocate interrupts
  54  * @nvec:               The number of interrupts to allocate
  55  * @write_msi_msg:      Callback to write an interrupt message for @dev
  56  *
  57  * Returns:
  58  * Zero for success, or an error code in case of failure
  59  *
  60  * This creates a MSI domain on @dev which has @dev->msi.domain as
  61  * parent. The parent domain sets up the new domain. The domain has
  62  * a fixed size of @nvec. The domain is managed by devres and will
  63  * be removed when the device is removed.
  64  *
  65  * Note: For migration purposes this falls back to the original platform_msi code
  66  *       up to the point where all platforms have been converted to the MSI
  67  *       parent model.
  68  */
  69 int platform_device_msi_init_and_alloc_irqs(struct device *dev, unsigned int nvec,
  70                                             irq_write_msi_msg_t write_msi_msg)
  71 {
  72         struct irq_domain *domain = dev->msi.domain;
  73
  74         if (!domain || !write_msi_msg)
  75                 return -EINVAL;
  76
  77         /*
  78          * @write_msi_msg is stored in the resulting msi_domain_info::data.
  79          * The underlying domain creation mechanism will assign that
  80          * callback to the resulting irq chip.
  81          */
  82         if (!msi_create_device_irq_domain(dev, MSI_DEFAULT_DOMAIN,
  83                                           &platform_msi_template,
  84                                           nvec, NULL, write_msi_msg))
  85                 return -ENODEV;
  86
  87         return msi_domain_alloc_irqs_range(dev, MSI_DEFAULT_DOMAIN, 0, nvec - 1);
  88 }
  89 EXPORT_SYMBOL_GPL(platform_device_msi_init_and_alloc_irqs);
  90
  91 /**
  92  * platform_device_msi_free_irqs_all - Free all interrupts for @dev
  93  * @dev:        The device for which to free interrupts
  94  */
  95 void platform_device_msi_free_irqs_all(struct device *dev)
  96 {
  97         msi_domain_free_irqs_all(dev, MSI_DEFAULT_DOMAIN);
  98 }
  99 EXPORT_SYMBOL_GPL(platform_device_msi_free_irqs_all);