source: trunk/packages/xen-3.1/xen-3.1/linux-2.6-xen-sparse/drivers/xen/pciback/pciback_ops.c @ 34

Last change on this file since 34 was 34, checked in by hartmans, 18 years ago

Add xen and xen-common

File size: 2.8 KB
Line 
1/*
2 * PCI Backend Operations - respond to PCI requests from Frontend
3 *
4 *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
5 */
6#include <linux/module.h>
7#include <asm/bitops.h>
8#include <xen/evtchn.h>
9#include "pciback.h"
10
11int verbose_request = 0;
12module_param(verbose_request, int, 0644);
13
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)
17 */
18void pciback_reset_device(struct pci_dev *dev)
19{
20        u16 cmd;
21
22        /* Disable devices (but not bridges) */
23        if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) {
24                pci_disable_device(dev);
25
26                pci_write_config_word(dev, PCI_COMMAND, 0);
27
28                dev->is_enabled = 0;
29                dev->is_busmaster = 0;
30        } else {
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);
35
36                        dev->is_busmaster = 0;
37                }
38        }
39}
40
41static inline void test_and_schedule_op(struct pciback_device *pdev)
42{
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);
48}
49
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 */
54void pciback_do_op(void *data)
55{
56        struct pciback_device *pdev = data;
57        struct pci_dev *dev;
58        struct xen_pci_op *op = &pdev->sh_info->op;
59
60        dev = pciback_get_pci_dev(pdev, op->domain, op->bus, op->devfn);
61
62        if (dev == NULL)
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,
66                                              &op->value);
67        else if (op->cmd == XEN_PCI_OP_conf_write)
68                op->err = pciback_config_write(dev, op->offset, op->size,
69                                               op->value);
70        else
71                op->err = XEN_PCI_ERR_not_implemented;
72
73        /* Tell the driver domain that we're done. */ 
74        wmb();
75        clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
76        notify_remote_via_irq(pdev->evtchn_irq);
77
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 */
82
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);
86}
87
88irqreturn_t pciback_handle_event(int irq, void *dev_id, struct pt_regs *regs)
89{
90        struct pciback_device *pdev = dev_id;
91
92        test_and_schedule_op(pdev);
93
94        return IRQ_HANDLED;
95}
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