LCOV - code coverage report
Current view: top level - drivers/pci - setup-irq.c (source / functions) Hit Total Coverage
Test: combined.info Lines: 8 20 40.0 %
Date: 2022-04-01 13:59:58 Functions: 1 1 100.0 %
Branches: 1 10 10.0 %

           Branch data     Line data    Source code
       1                 :            : // SPDX-License-Identifier: GPL-2.0
       2                 :            : /*
       3                 :            :  * Support routines for initializing a PCI subsystem
       4                 :            :  *
       5                 :            :  * Extruded from code written by
       6                 :            :  *      Dave Rusling (david.rusling@reo.mts.dec.com)
       7                 :            :  *      David Mosberger (davidm@cs.arizona.edu)
       8                 :            :  *      David Miller (davem@redhat.com)
       9                 :            :  */
      10                 :            : 
      11                 :            : 
      12                 :            : #include <linux/kernel.h>
      13                 :            : #include <linux/pci.h>
      14                 :            : #include <linux/errno.h>
      15                 :            : #include <linux/ioport.h>
      16                 :            : #include <linux/cache.h>
      17                 :            : #include "pci.h"
      18                 :            : 
      19                 :        390 : void pci_assign_irq(struct pci_dev *dev)
      20                 :            : {
      21                 :        390 :         u8 pin;
      22                 :        390 :         u8 slot = -1;
      23                 :        390 :         int irq = 0;
      24                 :        390 :         struct pci_host_bridge *hbrg = pci_find_host_bridge(dev->bus);
      25                 :            : 
      26         [ +  - ]:        390 :         if (!(hbrg->map_irq)) {
      27                 :        390 :                 pci_dbg(dev, "runtime IRQ mapping not provided by arch\n");
      28                 :        390 :                 return;
      29                 :            :         }
      30                 :            : 
      31                 :            :         /* If this device is not on the primary bus, we need to figure out
      32                 :            :            which interrupt pin it will come in on.   We know which slot it
      33                 :            :            will come in on 'cos that slot is where the bridge is.   Each
      34                 :            :            time the interrupt line passes through a PCI-PCI bridge we must
      35                 :            :            apply the swizzle function.  */
      36                 :            : 
      37                 :          0 :         pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
      38                 :            :         /* Cope with illegal. */
      39         [ #  # ]:          0 :         if (pin > 4)
      40                 :          0 :                 pin = 1;
      41                 :            : 
      42         [ #  # ]:          0 :         if (pin) {
      43                 :            :                 /* Follow the chain of bridges, swizzling as we go.  */
      44         [ #  # ]:          0 :                 if (hbrg->swizzle_irq)
      45                 :          0 :                         slot = (*(hbrg->swizzle_irq))(dev, &pin);
      46                 :            : 
      47                 :            :                 /*
      48                 :            :                  * If a swizzling function is not used map_irq must
      49                 :            :                  * ignore slot
      50                 :            :                  */
      51                 :          0 :                 irq = (*(hbrg->map_irq))(dev, slot, pin);
      52         [ #  # ]:          0 :                 if (irq == -1)
      53                 :          0 :                         irq = 0;
      54                 :            :         }
      55                 :          0 :         dev->irq = irq;
      56                 :            : 
      57                 :          0 :         pci_dbg(dev, "assign IRQ: got %d\n", dev->irq);
      58                 :            : 
      59                 :            :         /* Always tell the device, so the driver knows what is
      60                 :            :            the real IRQ to use; the device does not use it. */
      61                 :          0 :         pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq);
      62                 :            : }

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