path: root/drivers/pci/xen-pcifront.c

/*
 * Xen PCI Frontend.
 *
 *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <xen/xenbus.h>
#include <xen/events.h>
#include <xen/grant_table.h>
#include <xen/page.h>
#include <linux/spinlock.h>
#include <linux/pci.h>
#include <linux/msi.h>
#include <xen/interface/io/pciif.h>
#include <asm/xen/pci.h>
#include <linux/interrupt.h>
#include <linux/atomic.h>
#include <linux/workqueue.h>
#include <linux/bitops.h>
#include <linux/time.h>

#define INVALID_GRANT_REF (0)
#define INVALID_EVTCHN    (-1)

struct pci_bus_entry {
	struct list_head list;
	struct pci_bus *bus;
};

#define _PDEVB_op_active		(0)
#define PDEVB_op_active			(1 << (_PDEVB_op_active))

struct pcifront_device {
	struct xenbus_device *xdev;
	struct list_head root_buses;

	int evtchn;
	int gnt_ref;

	int irq;

	/* Lock this when doing any operations in sh_info */
	spinlock_t sh_info_lock;
	struct xen_pci_sharedinfo *sh_info;
	struct work_struct op_work;
	unsigned long flags;

};

struct pcifront_sd {
	int domain;
	struct pcifront_device *pdev;
};

static inline struct pcifront_device *
pcifront_get_pdev(struct pcifront_sd *sd)
{
	return sd->pdev;
}

static inline void pcifront_init_sd(struct pcifront_sd *sd,
				    unsigned int domain, unsigned int bus,
				    struct pcifront_device *pdev)
{
	sd->domain = domain;
	sd->pdev = pdev;
}

static DEFINE_SPINLOCK(pcifront_dev_lock);
static struct pcifront_device *pcifront_dev;

static int verbose_request;
module_param(verbose_request, int, 0644);

static int errno_to_pcibios_err(int errno)
{
	switch (errno) {
	case XEN_PCI_ERR_success:
		return PCIBIOS_SUCCESSFUL;

	case XEN_PCI_ERR_dev_not_found:
		return PCIBIOS_DEVICE_NOT_FOUND;

	case XEN_PCI_ERR_invalid_offset:
	case XEN_PCI_ERR_op_failed:
		return PCIBIOS_BAD_REGISTER_NUMBER;

	case XEN_PCI_ERR_not_implemented:
		return PCIBIOS_FUNC_NOT_SUPPORTED;

	case XEN_PCI_ERR_access_denied:
		return PCIBIOS_SET_FAILED;
	}
	return errno;
}

static inline void schedule_pcifront_aer_op(struct pcifront_device *pdev)
{
	if (test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
		&& !test_and_set_bit(_PDEVB_op_active, &pdev->flags)) {
		dev_dbg(&pdev->xdev->dev, "schedule aer frontend job\n");
		schedule_work(&pdev->op_work);
	}
}

static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
{
	int err = 0;
	struct xen_pci_op *active_op = &pdev->sh_info->op;
	unsigned long irq_flags;
	evtchn_port_t port = pdev->evtchn;
	unsigned irq = pdev->irq;
	s64 ns, ns_timeout;
	struct timeval tv;

	spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);

	memcpy(active_op, op, sizeof(struct xen_pci_op));

	/* Go */
	wmb();
	set_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
	notify_remote_via_evtchn(port);

	/*
	 * We set a poll timeout of 3 seconds but give up on return after
	 * 2 seconds. It is better to time out too late rather than too early
	 * (in the latter case we end up continually re-executing poll() with a
	 * timeout in the past). 1s difference gives plenty of slack for error.
	 */
	do_gettimeofday(&tv);
	ns_timeout =