drivers/pci/htirq.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * File:        htirq.c
   4  * Purpose:     Hypertransport Interrupt Capability
   5  *
   6  * Copyright (C) 2006 Linux Networx
   7  * Copyright (C) Eric Biederman <ebiederman@lnxi.com>
   8  */
   9
  10 #include <linux/irq.h>
  11 #include <linux/pci.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/export.h>
  14 #include <linux/slab.h>
  15 #include <linux/htirq.h>
  16
  17 /* Global ht irq lock.
  18  *
  19  * This is needed to serialize access to the data port in hypertransport
  20  * irq capability.
  21  *
  22  * With multiple simultaneous hypertransport irq devices it might pay
  23  * to make this more fine grained.  But start with simple, stupid, and correct.
  24  */
  25 static DEFINE_SPINLOCK(ht_irq_lock);
  26
  27 void write_ht_irq_msg(unsigned int irq, struct ht_irq_msg *msg)
  28 {
  29         struct ht_irq_cfg *cfg = irq_get_handler_data(irq);
  30         unsigned long flags;
  31
  32         spin_lock_irqsave(&ht_irq_lock, flags);
  33         if (cfg->msg.address_lo != msg->address_lo) {
  34                 pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx);
  35                 pci_write_config_dword(cfg->dev, cfg->pos + 4, msg->address_lo);
  36         }
  37         if (cfg->msg.address_hi != msg->address_hi) {
  38                 pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx + 1);
  39                 pci_write_config_dword(cfg->dev, cfg->pos + 4, msg->address_hi);
  40         }
  41         if (cfg->update)
  42                 cfg->update(cfg->dev, irq, msg);
  43         spin_unlock_irqrestore(&ht_irq_lock, flags);
  44         cfg->msg = *msg;
  45 }
  46
  47 void fetch_ht_irq_msg(unsigned int irq, struct ht_irq_msg *msg)
  48 {
  49         struct ht_irq_cfg *cfg = irq_get_handler_data(irq);
  50
  51         *msg = cfg->msg;
  52 }
  53
  54 void mask_ht_irq(struct irq_data *data)
  55 {
  56         struct ht_irq_cfg *cfg = irq_data_get_irq_handler_data(data);
  57         struct ht_irq_msg msg = cfg->msg;
  58
  59         msg.address_lo |= 1;
  60         write_ht_irq_msg(data->irq, &msg);
  61 }
  62
  63 void unmask_ht_irq(struct irq_data *data)
  64 {
  65         struct ht_irq_cfg *cfg = irq_data_get_irq_handler_data(data);
  66         struct ht_irq_msg msg = cfg->msg;
  67
  68         msg.address_lo &= ~1;
  69         write_ht_irq_msg(data->irq, &msg);
  70 }
  71
  72 /**
  73  * __ht_create_irq - create an irq and attach it to a device.
  74  * @dev: The hypertransport device to find the irq capability on.
  75  * @idx: Which of the possible irqs to attach to.
  76  * @update: Function to be called when changing the htirq message
  77  *
  78  * The irq number of the new irq or a negative error value is returned.
  79  */
  80 int __ht_create_irq(struct pci_dev *dev, int idx, ht_irq_update_t *update)
  81 {
  82         int max_irq, pos, irq;
  83         unsigned long flags;
  84         u32 data;
  85
  86         pos = pci_find_ht_capability(dev, HT_CAPTYPE_IRQ);
  87         if (!pos)
  88                 return -EINVAL;
  89
  90         /* Verify the idx I want to use is in range */
  91         spin_lock_irqsave(&ht_irq_lock, flags);
  92         pci_write_config_byte(dev, pos + 2, 1);
  93         pci_read_config_dword(dev, pos + 4, &data);
  94         spin_unlock_irqrestore(&ht_irq_lock, flags);
  95
  96         max_irq = (data >> 16) & 0xff;
  97         if (idx > max_irq)
  98                 return -EINVAL;
  99
 100         irq = arch_setup_ht_irq(idx, pos, dev, update);
 101         if (irq > 0)
 102                 dev_dbg(&dev->dev, "irq %d for HT\n", irq);
 103
 104         return irq;
 105 }
 106 EXPORT_SYMBOL(__ht_create_irq);
 107
 108 /**
 109  * ht_create_irq - create an irq and attach it to a device.
 110  * @dev: The hypertransport device to find the irq capability on.
 111  * @idx: Which of the possible irqs to attach to.
 112  *
 113  * ht_create_irq needs to be called for all hypertransport devices
 114  * that generate irqs.
 115  *
 116  * The irq number of the new irq or a negative error value is returned.
 117  */
 118 int ht_create_irq(struct pci_dev *dev, int idx)
 119 {
 120         return __ht_create_irq(dev, idx, NULL);
 121 }
 122 EXPORT_SYMBOL(ht_create_irq);
 123
 124 /**
 125  * ht_destroy_irq - destroy an irq created with ht_create_irq
 126  * @irq: irq to be destroyed
 127  *
 128  * This reverses ht_create_irq removing the specified irq from
 129  * existence.  The irq should be free before this happens.
 130  */
 131 void ht_destroy_irq(unsigned int irq)
 132 {
 133         arch_teardown_ht_irq(irq);
 134 }
 135 EXPORT_SYMBOL(ht_destroy_irq);