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PCI interrupts work

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Ciro Santilli
2017-06-17 22:58:00 +01:00
parent 4b7ce59e45
commit de6c179fc0
2 changed files with 50 additions and 12 deletions
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47
kernel_module/pci.c
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@@ -22,6 +22,7 @@ Grep QEMU source for the device description, and keep it open at all times!
#include <linux/cdev.h> /* cdev_ */
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
@@ -46,22 +47,23 @@ Grep QEMU source for the device description, and keep it open at all times!
* memory_region_init_io(&edu->mmio, OBJECT(edu), &edu_mmio_ops, edu,
* "edu-mmio", 1 << 20);
* pci_register_bar(pdev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &edu->mmio);
* */
**/
#define BAR 0
#define CDEV_NAME "lkmc_pci"
#define EDU_DEVICE_ID 0x11e8
#define IO_IRQ_ACK 0x64
#define IO_IRQ_STATUS 0x24
#define QEMU_VENDOR_ID 0x1234
MODULE_LICENSE("GPL");
/**
* 0x1234: QEMU vendor ID
* 0x11e8: edu device ID
*/
static struct pci_device_id pci_ids[] = {
{ PCI_DEVICE(0x1234, 0x11e8), },
{ PCI_DEVICE(QEMU_VENDOR_ID, EDU_DEVICE_ID), },
{ 0, }
};
MODULE_DEVICE_TABLE(pci, pci_ids);
static int pci_irq;
static int major;
static struct pci_dev *pdev;
static void __iomem *mmio;
@@ -119,6 +121,26 @@ static struct file_operations fops = {
.write = write,
};
static irqreturn_t irq_handler(int irq, void *dev)
{
int devi;
irqreturn_t ret;
u32 irq_status;
devi = *(int *)dev;
if (devi == major) {
irq_status = ioread32(mmio + IO_IRQ_STATUS);
pr_info("interrupt irq = %d dev = %d irq_status = %llx\n",
irq, devi, (unsigned long long)irq_status);
/* Must do this ACK, or else the interrupts just keeps firing. */
iowrite32(irq_status, mmio + IO_IRQ_ACK);
ret = IRQ_HANDLED;
} else {
ret = IRQ_NONE;
}
return ret;
}
/**
* Called just after insmod if the hardware device is connected,
* not called otherwise.
@@ -128,6 +150,8 @@ static struct file_operations fops = {
*/
static int pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
u8 val;
pr_info("pci_probe\n");
major = register_chrdev(0, CDEV_NAME, &fops);
pdev = dev;
@@ -141,9 +165,16 @@ static int pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
}
mmio = pci_iomap(pdev, BAR, pci_resource_len(pdev, BAR));
/* IRQ setup. */
pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &val);
pci_irq = val;
if (request_irq(pci_irq, irq_handler, IRQF_SHARED, "pci_irq_handler0", &major) < 0) {
dev_err(&(dev->dev), "request_irq\n");
goto error;
}
/* Optional sanity checks. The PCI is ready now, all of this could also be called from fops. */
{
u8 val;
unsigned i;
/* Check that we are using MEM instead of IO.
@@ -168,13 +199,13 @@ static int pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
pci_read_config_byte(pdev, i, &val);
pr_info("config %x %x\n", i, val);
}
pr_info("irq %x\n", pci_irq);
/* Initial value of the IO memory. */
for (i = 0; i < 0x28; i += 4) {
pr_info("io %x %x\n", i, ioread32((void*)(mmio + i)));
}
}
return 0;
error:
return 1;