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/**
*
* @file int.c
* @author Guillermo Marcus
* @date 2009-04-05
* @brief Contains the interrupt handler.
*
*/
#include <linux/version.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/cdev.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <stdbool.h>
#include "base.h"
/**
*
* Acknowledges the receival of an interrupt to the card.
*
* @returns true if the card was acknowledget
* @returns false if the interrupt was not for one of our cards
*
* @see check_acknowlegde_channel
*
*/
static bool pcidriver_irq_acknowledge(pcidriver_privdata_t *privdata)
{
int channel = 0;
atomic_inc(&(privdata->irq_outstanding[channel]));
wake_up_interruptible(&(privdata->irq_queues[channel]));
return true;
}
/**
*
* Handles IRQs. At the moment, this acknowledges the card that this IRQ
* was received and then increases the driver's IRQ counter.
*
* @see pcidriver_irq_acknowledge
*
*/
static irqreturn_t pcidriver_irq_handler(int irq, void *dev_id)
{
pcidriver_privdata_t *privdata = (pcidriver_privdata_t *)dev_id;
if (!pcidriver_irq_acknowledge(privdata))
return IRQ_NONE;
privdata->irq_count++;
return IRQ_HANDLED;
}
/**
*
* If IRQ-handling is enabled, this function will be called from pcidriver_probe
* to initialize the IRQ handling (maps the BARs)
*
*/
int pcidriver_probe_irq(pcidriver_privdata_t *privdata)
{
unsigned char int_pin, int_line;
unsigned long bar_addr, bar_len, bar_flags;
int i;
int err;
for (i = 0; i < 6; i++)
privdata->bars_kmapped[i] = NULL;
for (i = 0; i < 6; i++) {
bar_addr = pci_resource_start(privdata->pdev, i);
bar_len = pci_resource_len(privdata->pdev, i);
bar_flags = pci_resource_flags(privdata->pdev, i);
/* check if it is a valid BAR, skip if not */
if ((bar_addr == 0) || (bar_len == 0))
continue;
/* Skip IO regions (map only mem regions) */
if (bar_flags & IORESOURCE_IO)
continue;
/* Check if the region is available */
if ((err = pci_request_region(privdata->pdev, i, NULL)) != 0) {
mod_info( "Failed to request BAR memory region.\n" );
return err;
}
/* Map it into kernel space. */
/* For x86 this is just a dereference of the pointer, but that is
* not portable. So we need to do the portable way. Thanks Joern!
*/
/* respect the cacheable-bility of the region */
if (bar_flags & IORESOURCE_PREFETCH)
privdata->bars_kmapped[i] = ioremap(bar_addr, bar_len);
else
privdata->bars_kmapped[i] = ioremap_nocache(bar_addr, bar_len);
/* check for error */
if (privdata->bars_kmapped[i] == NULL) {
mod_info( "Failed to remap BAR%d into kernel space.\n", i );
return -EIO;
}
}
/* Initialize the interrupt handler for this device */
/* Initialize the wait queues */
for (i = 0; i < PCIDRIVER_INT_MAXSOURCES; i++) {
init_waitqueue_head(&(privdata->irq_queues[i]));
atomic_set(&(privdata->irq_outstanding[i]), 0);
}
/* Initialize the irq config */
if ((err = pci_read_config_byte(privdata->pdev, PCI_INTERRUPT_PIN, &int_pin)) != 0) {
/* continue without interrupts */
int_pin = 0;
mod_info("Error getting the interrupt pin. Disabling interrupts for this device\n");
}
/* Disable interrupts and activate them if everything can be set up properly */
privdata->irq_enabled = 0;
if (int_pin == 0)
return 0;
if ((err = pci_read_config_byte(privdata->pdev, PCI_INTERRUPT_LINE, &int_line)) != 0) {
mod_info("Error getting the interrupt line. Disabling interrupts for this device\n");
return 0;
}
/* Enable interrupts using MSI mode */
if (!pci_enable_msi(privdata->pdev))
privdata->msi_mode = 1;
/* register interrupt handler */
if ((err = request_irq(privdata->pdev->irq, pcidriver_irq_handler, IRQF_SHARED, MODNAME, privdata)) != 0) {
mod_info("Error registering the interrupt handler. Disabling interrupts for this device\n");
return 0;
}
privdata->irq_enabled = 1;
mod_info("Registered Interrupt Handler at pin %i, line %i, IRQ %i\n", int_pin, int_line, privdata->pdev->irq );
return 0;
}
/**
*
* Frees/cleans up the data structures, called from pcidriver_remove()
*
*/
void pcidriver_remove_irq(pcidriver_privdata_t *privdata)
{
/* Release the IRQ handler */
if (privdata->irq_enabled != 0)
free_irq(privdata->pdev->irq, privdata);
if (privdata->msi_mode) {
pci_disable_msi(privdata->pdev);
privdata->msi_mode = 0;
}
pcidriver_irq_unmap_bars(privdata);
}
/**
*
* Unmaps the BARs and releases them
*
*/
void pcidriver_irq_unmap_bars(pcidriver_privdata_t *privdata)
{
int i;
for (i = 0; i < 6; i++) {
if (privdata->bars_kmapped[i] == NULL)
continue;
iounmap((void*)privdata->bars_kmapped[i]);
pci_release_region(privdata->pdev, i);
}
}
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