diff options
Diffstat (limited to 'drivers/xen/xen-pciback/pciback_ops.c')
| -rw-r--r-- | drivers/xen/xen-pciback/pciback_ops.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/drivers/xen/xen-pciback/pciback_ops.c b/drivers/xen/xen-pciback/pciback_ops.c new file mode 100644 index 000000000000..2b9a93e1fdee --- /dev/null +++ b/drivers/xen/xen-pciback/pciback_ops.c @@ -0,0 +1,131 @@ +/* + * PCI Backend Operations - respond to PCI requests from Frontend + * + * Author: Ryan Wilson <hap9@epoch.ncsc.mil> + */ +#include <linux/module.h> +#include <linux/wait.h> +#include <linux/bitops.h> +#include <xen/events.h> +#include <linux/sched.h> +#include "pciback.h" + +int verbose_request; +module_param(verbose_request, int, 0644); + +/* Ensure a device is "turned off" and ready to be exported. + * (Also see pciback_config_reset to ensure virtual configuration space is + * ready to be re-exported) + */ +void pciback_reset_device(struct pci_dev *dev) +{ + u16 cmd; + + /* Disable devices (but not bridges) */ + if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) { + pci_disable_device(dev); + + pci_write_config_word(dev, PCI_COMMAND, 0); + + dev->is_busmaster = 0; + } else { + pci_read_config_word(dev, PCI_COMMAND, &cmd); + if (cmd & (PCI_COMMAND_INVALIDATE)) { + cmd &= ~(PCI_COMMAND_INVALIDATE); + pci_write_config_word(dev, PCI_COMMAND, cmd); + + dev->is_busmaster = 0; + } + } +} +/* +* Now the same evtchn is used for both pcifront conf_read_write request +* as well as pcie aer front end ack. We use a new work_queue to schedule +* pciback conf_read_write service for avoiding confict with aer_core +* do_recovery job which also use the system default work_queue +*/ +void test_and_schedule_op(struct pciback_device *pdev) +{ + /* Check that frontend is requesting an operation and that we are not + * already processing a request */ + if (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags) + && !test_and_set_bit(_PDEVF_op_active, &pdev->flags)) { + queue_work(pciback_wq, &pdev->op_work); + } + /*_XEN_PCIB_active should have been cleared by pcifront. And also make + sure pciback is waiting for ack by checking _PCIB_op_pending*/ + if (!test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags) + && test_bit(_PCIB_op_pending, &pdev->flags)) { + wake_up(&aer_wait_queue); + } +} + +/* Performing the configuration space reads/writes must not be done in atomic + * context because some of the pci_* functions can sleep (mostly due to ACPI + * use of semaphores). This function is intended to be called from a work + * queue in process context taking a struct pciback_device as a parameter */ + +void pciback_do_op(struct work_struct *data) +{ + struct pciback_device *pdev = + container_of(data, struct pciback_device, op_work); + struct pci_dev *dev; + struct xen_pci_op *op = &pdev->sh_info->op; + + dev = pciback_get_pci_dev(pdev, op->domain, op->bus, op->devfn); + + if (dev == NULL) + op->err = XEN_PCI_ERR_dev_not_found; + else { + switch (op->cmd) { + case XEN_PCI_OP_conf_read: + op->err = pciback_config_read(dev, + op->offset, op->size, &op->value); + break; + case XEN_PCI_OP_conf_write: + op->err = pciback_config_write(dev, + op->offset, op->size, op->value); + break; +#ifdef CONFIG_PCI_MSI + case XEN_PCI_OP_enable_msi: + op->err = pciback_enable_msi(pdev, dev, op); + break; + case XEN_PCI_OP_disable_msi: + op->err = pciback_disable_msi(pdev, dev, op); + break; + case XEN_PCI_OP_enable_msix: + op->err = pciback_enable_msix(pdev, dev, op); + break; + case XEN_PCI_OP_disable_msix: + op->err = pciback_disable_msix(pdev, dev, op); + break; +#endif + default: + op->err = XEN_PCI_ERR_not_implemented; + break; + } + } + /* Tell the driver domain that we're done. */ + wmb(); + clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags); + notify_remote_via_irq(pdev->evtchn_irq); + + /* Mark that we're done. */ + smp_mb__before_clear_bit(); /* /after/ clearing PCIF_active */ + clear_bit(_PDEVF_op_active, &pdev->flags); + smp_mb__after_clear_bit(); /* /before/ final check for work */ + + /* Check to see if the driver domain tried to start another request in + * between clearing _XEN_PCIF_active and clearing _PDEVF_op_active. + */ + test_and_schedule_op(pdev); +} + +irqreturn_t pciback_handle_event(int irq, void *dev_id) +{ + struct pciback_device *pdev = dev_id; + + test_and_schedule_op(pdev); + + return IRQ_HANDLED; +} |