2 * PCI Backend Operations - respond to PCI requests from Frontend
4 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
6 #include <linux/module.h>
7 #include <asm/bitops.h>
8 #include <xen/evtchn.h>
11 int verbose_request = 0;
12 module_param(verbose_request, int, 0644);
14 /* Ensure a device is "turned off" and ready to be exported.
15 * (Also see pciback_config_reset to ensure virtual configuration space is
16 * ready to be re-exported)
18 void pciback_reset_device(struct pci_dev *dev)
22 /* Disable devices (but not bridges) */
23 if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) {
24 pci_disable_device(dev);
26 pci_write_config_word(dev, PCI_COMMAND, 0);
28 dev->is_busmaster = 0;
30 pci_read_config_word(dev, PCI_COMMAND, &cmd);
31 if (cmd & (PCI_COMMAND_INVALIDATE)) {
32 cmd &= ~(PCI_COMMAND_INVALIDATE);
33 pci_write_config_word(dev, PCI_COMMAND, cmd);
35 dev->is_busmaster = 0;
40 static inline void test_and_schedule_op(struct pciback_device *pdev)
42 /* Check that frontend is requesting an operation and that we are not
43 * already processing a request */
44 if (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags)
45 && !test_and_set_bit(_PDEVF_op_active, &pdev->flags))
46 schedule_delayed_work(&pdev->op_work, 0);
49 /* Performing the configuration space reads/writes must not be done in atomic
50 * context because some of the pci_* functions can sleep (mostly due to ACPI
51 * use of semaphores). This function is intended to be called from a work
52 * queue in process context taking a struct pciback_device as a parameter */
53 void pciback_do_op(struct work_struct *work)
55 struct pciback_device *pdev = container_of(work, struct pciback_device, op_work.work);
57 struct xen_pci_op *op = &pdev->sh_info->op;
59 dev = pciback_get_pci_dev(pdev, op->domain, op->bus, op->devfn);
62 op->err = XEN_PCI_ERR_dev_not_found;
63 else if (op->cmd == XEN_PCI_OP_conf_read)
64 op->err = pciback_config_read(dev, op->offset, op->size,
66 else if (op->cmd == XEN_PCI_OP_conf_write)
67 op->err = pciback_config_write(dev, op->offset, op->size,
70 op->err = XEN_PCI_ERR_not_implemented;
72 /* Tell the driver domain that we're done. */
74 clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
75 notify_remote_via_irq(pdev->evtchn_irq);
77 /* Mark that we're done. */
78 smp_mb__before_clear_bit(); /* /after/ clearing PCIF_active */
79 clear_bit(_PDEVF_op_active, &pdev->flags);
80 smp_mb__after_clear_bit(); /* /before/ final check for work */
82 /* Check to see if the driver domain tried to start another request in
83 * between clearing _XEN_PCIF_active and clearing _PDEVF_op_active. */
84 test_and_schedule_op(pdev);
87 irqreturn_t pciback_handle_event(int irq, void *dev_id)
89 struct pciback_device *pdev = dev_id;
91 test_and_schedule_op(pdev);