mirror of
https://github.com/torvalds/linux.git
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132 lines
3.9 KiB
C
132 lines
3.9 KiB
C
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/*
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* PCI Backend Operations - respond to PCI requests from Frontend
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*
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* Author: Ryan Wilson <hap9@epoch.ncsc.mil>
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*/
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#include <linux/module.h>
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#include <linux/wait.h>
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#include <linux/bitops.h>
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#include <xen/events.h>
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#include <linux/sched.h>
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#include "pciback.h"
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int verbose_request;
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module_param(verbose_request, int, 0644);
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/* Ensure a device is "turned off" and ready to be exported.
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* (Also see pciback_config_reset to ensure virtual configuration space is
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* ready to be re-exported)
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*/
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void pciback_reset_device(struct pci_dev *dev)
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{
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u16 cmd;
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/* Disable devices (but not bridges) */
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if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) {
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pci_disable_device(dev);
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pci_write_config_word(dev, PCI_COMMAND, 0);
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dev->is_busmaster = 0;
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} else {
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pci_read_config_word(dev, PCI_COMMAND, &cmd);
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if (cmd & (PCI_COMMAND_INVALIDATE)) {
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cmd &= ~(PCI_COMMAND_INVALIDATE);
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pci_write_config_word(dev, PCI_COMMAND, cmd);
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dev->is_busmaster = 0;
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}
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}
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}
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/*
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* Now the same evtchn is used for both pcifront conf_read_write request
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* as well as pcie aer front end ack. We use a new work_queue to schedule
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* pciback conf_read_write service for avoiding confict with aer_core
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* do_recovery job which also use the system default work_queue
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*/
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void test_and_schedule_op(struct pciback_device *pdev)
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{
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/* Check that frontend is requesting an operation and that we are not
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* already processing a request */
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if (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags)
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&& !test_and_set_bit(_PDEVF_op_active, &pdev->flags)) {
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queue_work(pciback_wq, &pdev->op_work);
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}
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/*_XEN_PCIB_active should have been cleared by pcifront. And also make
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sure pciback is waiting for ack by checking _PCIB_op_pending*/
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if (!test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
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&& test_bit(_PCIB_op_pending, &pdev->flags)) {
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wake_up(&aer_wait_queue);
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}
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}
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/* Performing the configuration space reads/writes must not be done in atomic
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* context because some of the pci_* functions can sleep (mostly due to ACPI
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* use of semaphores). This function is intended to be called from a work
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* queue in process context taking a struct pciback_device as a parameter */
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void pciback_do_op(struct work_struct *data)
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{
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struct pciback_device *pdev =
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container_of(data, struct pciback_device, op_work);
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struct pci_dev *dev;
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struct xen_pci_op *op = &pdev->sh_info->op;
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dev = pciback_get_pci_dev(pdev, op->domain, op->bus, op->devfn);
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if (dev == NULL)
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op->err = XEN_PCI_ERR_dev_not_found;
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else {
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switch (op->cmd) {
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case XEN_PCI_OP_conf_read:
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op->err = pciback_config_read(dev,
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op->offset, op->size, &op->value);
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break;
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case XEN_PCI_OP_conf_write:
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op->err = pciback_config_write(dev,
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op->offset, op->size, op->value);
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break;
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#ifdef CONFIG_PCI_MSI
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case XEN_PCI_OP_enable_msi:
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op->err = pciback_enable_msi(pdev, dev, op);
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break;
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case XEN_PCI_OP_disable_msi:
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op->err = pciback_disable_msi(pdev, dev, op);
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break;
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case XEN_PCI_OP_enable_msix:
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op->err = pciback_enable_msix(pdev, dev, op);
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break;
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case XEN_PCI_OP_disable_msix:
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op->err = pciback_disable_msix(pdev, dev, op);
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break;
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#endif
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default:
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op->err = XEN_PCI_ERR_not_implemented;
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break;
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}
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}
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/* Tell the driver domain that we're done. */
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wmb();
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clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
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notify_remote_via_irq(pdev->evtchn_irq);
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/* Mark that we're done. */
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smp_mb__before_clear_bit(); /* /after/ clearing PCIF_active */
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clear_bit(_PDEVF_op_active, &pdev->flags);
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smp_mb__after_clear_bit(); /* /before/ final check for work */
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/* Check to see if the driver domain tried to start another request in
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* between clearing _XEN_PCIF_active and clearing _PDEVF_op_active.
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*/
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test_and_schedule_op(pdev);
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}
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irqreturn_t pciback_handle_event(int irq, void *dev_id)
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{
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struct pciback_device *pdev = dev_id;
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test_and_schedule_op(pdev);
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return IRQ_HANDLED;
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}
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