drivers/acpi/gsi.c

   1 /*
   2  * ACPI GSI IRQ layer
   3  *
   4  * Copyright (C) 2015 ARM Ltd.
   5  * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
   6  *
   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.
  10  */
  11 #include <linux/acpi.h>
  12 #include <linux/irq.h>
  13 #include <linux/irqdomain.h>
  14
  15 enum acpi_irq_model_id acpi_irq_model;
  16
  17 static unsigned int acpi_gsi_get_irq_type(int trigger, int polarity)
  18 {
  19         switch (polarity) {
  20         case ACPI_ACTIVE_LOW:
  21                 return trigger == ACPI_EDGE_SENSITIVE ?
  22                        IRQ_TYPE_EDGE_FALLING :
  23                        IRQ_TYPE_LEVEL_LOW;
  24         case ACPI_ACTIVE_HIGH:
  25                 return trigger == ACPI_EDGE_SENSITIVE ?
  26                        IRQ_TYPE_EDGE_RISING :
  27                        IRQ_TYPE_LEVEL_HIGH;
  28         case ACPI_ACTIVE_BOTH:
  29                 if (trigger == ACPI_EDGE_SENSITIVE)
  30                         return IRQ_TYPE_EDGE_BOTH;
  31         default:
  32                 return IRQ_TYPE_NONE;
  33         }
  34 }
  35
  36 /**
  37  * acpi_gsi_to_irq() - Retrieve the linux irq number for a given GSI
  38  * @gsi: GSI IRQ number to map
  39  * @irq: pointer where linux IRQ number is stored
  40  *
  41  * irq location updated with irq value [>0 on success, 0 on failure]
  42  *
  43  * Returns: linux IRQ number on success (>0)
  44  *          -EINVAL on failure
  45  */
  46 int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
  47 {
  48         /*
  49          * Only default domain is supported at present, always find
  50          * the mapping corresponding to default domain by passing NULL
  51          * as irq_domain parameter
  52          */
  53         *irq = irq_find_mapping(NULL, gsi);
  54         /*
  55          * *irq == 0 means no mapping, that should
  56          * be reported as a failure
  57          */
  58         return (*irq > 0) ? *irq : -EINVAL;
  59 }
  60 EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
  61
  62 /**
  63  * acpi_register_gsi() - Map a GSI to a linux IRQ number
  64  * @dev: device for which IRQ has to be mapped
  65  * @gsi: GSI IRQ number
  66  * @trigger: trigger type of the GSI number to be mapped
  67  * @polarity: polarity of the GSI to be mapped
  68  *
  69  * Returns: a valid linux IRQ number on success
  70  *          -EINVAL on failure
  71  */
  72 int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
  73                       int polarity)
  74 {
  75         unsigned int irq;
  76         unsigned int irq_type = acpi_gsi_get_irq_type(trigger, polarity);
  77
  78         /*
  79          * There is no way at present to look-up the IRQ domain on ACPI,
  80          * hence always create mapping referring to the default domain
  81          * by passing NULL as irq_domain parameter
  82          */
  83         irq = irq_create_mapping(NULL, gsi);
  84         if (!irq)
  85                 return -EINVAL;
  86
  87         /* Set irq type if specified and different than the current one */
  88         if (irq_type != IRQ_TYPE_NONE &&
  89                 irq_type != irq_get_trigger_type(irq))
  90                 irq_set_irq_type(irq, irq_type);
  91         return irq;
  92 }
  93 EXPORT_SYMBOL_GPL(acpi_register_gsi);
  94
  95 /**
  96  * acpi_unregister_gsi() - Free a GSI<->linux IRQ number mapping
  97  * @gsi: GSI IRQ number
  98  */
  99 void acpi_unregister_gsi(u32 gsi)
 100 {
 101         int irq = irq_find_mapping(NULL, gsi);
 102
 103         irq_dispose_mapping(irq);
 104 }
 105 EXPORT_SYMBOL_GPL(acpi_unregister_gsi);