drivers/base/auxiliary_sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES
   4  */
   5
   6 #include <linux/auxiliary_bus.h>
   7 #include <linux/slab.h>
   8
   9 #define AUXILIARY_MAX_IRQ_NAME 11
  10
  11 struct auxiliary_irq_info {
  12         struct device_attribute sysfs_attr;
  13         char name[AUXILIARY_MAX_IRQ_NAME];
  14 };
  15
  16 static struct attribute *auxiliary_irq_attrs[] = {
  17         NULL
  18 };
  19
  20 static const struct attribute_group auxiliary_irqs_group = {
  21         .name = "irqs",
  22         .attrs = auxiliary_irq_attrs,
  23 };
  24
  25 static int auxiliary_irq_dir_prepare(struct auxiliary_device *auxdev)
  26 {
  27         int ret = 0;
  28
  29         guard(mutex)(&auxdev->sysfs.lock);
  30         if (auxdev->sysfs.irq_dir_exists)
  31                 return 0;
  32
  33         ret = devm_device_add_group(&auxdev->dev, &auxiliary_irqs_group);
  34         if (ret)
  35                 return ret;
  36
  37         auxdev->sysfs.irq_dir_exists = true;
  38         xa_init(&auxdev->sysfs.irqs);
  39         return 0;
  40 }
  41
  42 /**
  43  * auxiliary_device_sysfs_irq_add - add a sysfs entry for the given IRQ
  44  * @auxdev: auxiliary bus device to add the sysfs entry.
  45  * @irq: The associated interrupt number.
  46  *
  47  * This function should be called after auxiliary device have successfully
  48  * received the irq.
  49  * The driver is responsible to add a unique irq for the auxiliary device. The
  50  * driver can invoke this function from multiple thread context safely for
  51  * unique irqs of the auxiliary devices. The driver must not invoke this API
  52  * multiple times if the irq is already added previously.
  53  *
  54  * Return: zero on success or an error code on failure.
  55  */
  56 int auxiliary_device_sysfs_irq_add(struct auxiliary_device *auxdev, int irq)
  57 {
  58         struct auxiliary_irq_info *info __free(kfree) = NULL;
  59         struct device *dev = &auxdev->dev;
  60         int ret;
  61
  62         ret = auxiliary_irq_dir_prepare(auxdev);
  63         if (ret)
  64                 return ret;
  65
  66         info = kzalloc(sizeof(*info), GFP_KERNEL);
  67         if (!info)
  68                 return -ENOMEM;
  69
  70         sysfs_attr_init(&info->sysfs_attr.attr);
  71         snprintf(info->name, AUXILIARY_MAX_IRQ_NAME, "%d", irq);
  72
  73         ret = xa_insert(&auxdev->sysfs.irqs, irq, info, GFP_KERNEL);
  74         if (ret)
  75                 return ret;
  76
  77         info->sysfs_attr.attr.name = info->name;
  78         ret = sysfs_add_file_to_group(&dev->kobj, &info->sysfs_attr.attr,
  79                                       auxiliary_irqs_group.name);
  80         if (ret)
  81                 goto sysfs_add_err;
  82
  83         xa_store(&auxdev->sysfs.irqs, irq, no_free_ptr(info), GFP_KERNEL);
  84         return 0;
  85
  86 sysfs_add_err:
  87         xa_erase(&auxdev->sysfs.irqs, irq);
  88         return ret;
  89 }
  90 EXPORT_SYMBOL_GPL(auxiliary_device_sysfs_irq_add);
  91
  92 /**
  93  * auxiliary_device_sysfs_irq_remove - remove a sysfs entry for the given IRQ
  94  * @auxdev: auxiliary bus device to add the sysfs entry.
  95  * @irq: the IRQ to remove.
  96  *
  97  * This function should be called to remove an IRQ sysfs entry.
  98  * The driver must invoke this API when IRQ is released by the device.
  99  */
 100 void auxiliary_device_sysfs_irq_remove(struct auxiliary_device *auxdev, int irq)
 101 {
 102         struct auxiliary_irq_info *info __free(kfree) = xa_load(&auxdev->sysfs.irqs, irq);
 103         struct device *dev = &auxdev->dev;
 104
 105         if (!info) {
 106                 dev_err(&auxdev->dev, "IRQ %d doesn't exist\n", irq);
 107                 return;
 108         }
 109         sysfs_remove_file_from_group(&dev->kobj, &info->sysfs_attr.attr,
 110                                      auxiliary_irqs_group.name);
 111         xa_erase(&auxdev->sysfs.irqs, irq);
 112 }
 113 EXPORT_SYMBOL_GPL(auxiliary_device_sysfs_irq_remove);