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);
29 dev->is_busmaster = 0;
31 pci_read_config_word(dev, PCI_COMMAND, &cmd);
32 if (cmd & (PCI_COMMAND_INVALIDATE)) {
33 cmd &= ~(PCI_COMMAND_INVALIDATE);
34 pci_write_config_word(dev, PCI_COMMAND, cmd);
36 dev->is_busmaster = 0;
41 static inline void test_and_schedule_op(struct pciback_device *pdev)
43 /* Check that frontend is requesting an operation and that we are not
44 * already processing a request */
45 if (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags)
46 && !test_and_set_bit(_PDEVF_op_active, &pdev->flags))
47 schedule_work(&pdev->op_work);
50 /* Performing the configuration space reads/writes must not be done in atomic
51 * context because some of the pci_* functions can sleep (mostly due to ACPI
52 * use of semaphores). This function is intended to be called from a work
53 * queue in process context taking a struct pciback_device as a parameter */
54 void pciback_do_op(void *data)
56 struct pciback_device *pdev = data;
58 struct xen_pci_op *op = &pdev->sh_info->op;
60 dev = pciback_get_pci_dev(pdev, op->domain, op->bus, op->devfn);
63 op->err = XEN_PCI_ERR_dev_not_found;
64 else if (op->cmd == XEN_PCI_OP_conf_read)
65 op->err = pciback_config_read(dev, op->offset, op->size,
67 else if (op->cmd == XEN_PCI_OP_conf_write)
68 op->err = pciback_config_write(dev, op->offset, op->size,
71 op->err = XEN_PCI_ERR_not_implemented;
73 /* Tell the driver domain that we're done. */
75 clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
76 notify_remote_via_irq(pdev->evtchn_irq);
78 /* Mark that we're done. */
79 smp_mb__before_clear_bit(); /* /after/ clearing PCIF_active */
80 clear_bit(_PDEVF_op_active, &pdev->flags);
81 smp_mb__after_clear_bit(); /* /before/ final check for work */
83 /* Check to see if the driver domain tried to start another request in
84 * between clearing _XEN_PCIF_active and clearing _PDEVF_op_active. */
85 test_and_schedule_op(pdev);
88 irqreturn_t pciback_handle_event(int irq, void *dev_id, struct pt_regs *regs)
90 struct pciback_device *pdev = dev_id;
92 test_and_schedule_op(pdev);