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 <linux/wait.h>
8 #include <linux/bitops.h>
9 #include <xen/events.h>
10 #include <linux/sched.h>
14 module_param(verbose_request, int, 0644);
16 /* Ensure a device is "turned off" and ready to be exported.
17 * (Also see pciback_config_reset to ensure virtual configuration space is
18 * ready to be re-exported)
20 void pciback_reset_device(struct pci_dev *dev)
24 /* Disable devices (but not bridges) */
25 if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) {
26 pci_disable_device(dev);
28 pci_write_config_word(dev, PCI_COMMAND, 0);
30 dev->is_busmaster = 0;
32 pci_read_config_word(dev, PCI_COMMAND, &cmd);
33 if (cmd & (PCI_COMMAND_INVALIDATE)) {
34 cmd &= ~(PCI_COMMAND_INVALIDATE);
35 pci_write_config_word(dev, PCI_COMMAND, cmd);
37 dev->is_busmaster = 0;
42 * Now the same evtchn is used for both pcifront conf_read_write request
43 * as well as pcie aer front end ack. We use a new work_queue to schedule
44 * pciback conf_read_write service for avoiding confict with aer_core
45 * do_recovery job which also use the system default work_queue
47 void test_and_schedule_op(struct pciback_device *pdev)
49 /* Check that frontend is requesting an operation and that we are not
50 * already processing a request */
51 if (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags)
52 && !test_and_set_bit(_PDEVF_op_active, &pdev->flags)) {
53 queue_work(pciback_wq, &pdev->op_work);
55 /*_XEN_PCIB_active should have been cleared by pcifront. And also make
56 sure pciback is waiting for ack by checking _PCIB_op_pending*/
57 if (!test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
58 && test_bit(_PCIB_op_pending, &pdev->flags)) {
59 wake_up(&aer_wait_queue);
63 /* Performing the configuration space reads/writes must not be done in atomic
64 * context because some of the pci_* functions can sleep (mostly due to ACPI
65 * use of semaphores). This function is intended to be called from a work
66 * queue in process context taking a struct pciback_device as a parameter */
68 void pciback_do_op(struct work_struct *data)
70 struct pciback_device *pdev =
71 container_of(data, struct pciback_device, op_work);
73 struct xen_pci_op *op = &pdev->sh_info->op;
75 dev = pciback_get_pci_dev(pdev, op->domain, op->bus, op->devfn);
78 op->err = XEN_PCI_ERR_dev_not_found;
81 case XEN_PCI_OP_conf_read:
82 op->err = pciback_config_read(dev,
83 op->offset, op->size, &op->value);
85 case XEN_PCI_OP_conf_write:
86 op->err = pciback_config_write(dev,
87 op->offset, op->size, op->value);
90 case XEN_PCI_OP_enable_msi:
91 op->err = pciback_enable_msi(pdev, dev, op);
93 case XEN_PCI_OP_disable_msi:
94 op->err = pciback_disable_msi(pdev, dev, op);
96 case XEN_PCI_OP_enable_msix:
97 op->err = pciback_enable_msix(pdev, dev, op);
99 case XEN_PCI_OP_disable_msix:
100 op->err = pciback_disable_msix(pdev, dev, op);
104 op->err = XEN_PCI_ERR_not_implemented;
108 /* Tell the driver domain that we're done. */
110 clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
111 notify_remote_via_irq(pdev->evtchn_irq);
113 /* Mark that we're done. */
114 smp_mb__before_clear_bit(); /* /after/ clearing PCIF_active */
115 clear_bit(_PDEVF_op_active, &pdev->flags);
116 smp_mb__after_clear_bit(); /* /before/ final check for work */
118 /* Check to see if the driver domain tried to start another request in
119 * between clearing _XEN_PCIF_active and clearing _PDEVF_op_active.
121 test_and_schedule_op(pdev);
124 irqreturn_t pciback_handle_event(int irq, void *dev_id)
126 struct pciback_device *pdev = dev_id;
128 test_and_schedule_op(pdev);