439 lines
11 KiB
C
439 lines
11 KiB
C
/*
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* PCI Backend - Functions for creating a virtual configuration space for
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* exported PCI Devices.
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* It's dangerous to allow PCI Driver Domains to change their
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* device's resources (memory, i/o ports, interrupts). We need to
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* restrict changes to certain PCI Configuration registers:
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* BARs, INTERRUPT_PIN, most registers in the header...
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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/kernel.h>
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#include <linux/pci.h>
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#include "pciback.h"
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#include "conf_space.h"
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#include "conf_space_quirks.h"
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#define DRV_NAME "xen-pciback"
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static int permissive;
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module_param(permissive, bool, 0644);
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/* This is where xen_pcibk_read_config_byte, xen_pcibk_read_config_word,
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* xen_pcibk_write_config_word, and xen_pcibk_write_config_byte are created. */
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#define DEFINE_PCI_CONFIG(op, size, type) \
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int xen_pcibk_##op##_config_##size \
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(struct pci_dev *dev, int offset, type value, void *data) \
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{ \
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return pci_##op##_config_##size(dev, offset, value); \
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}
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DEFINE_PCI_CONFIG(read, byte, u8 *)
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DEFINE_PCI_CONFIG(read, word, u16 *)
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DEFINE_PCI_CONFIG(read, dword, u32 *)
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DEFINE_PCI_CONFIG(write, byte, u8)
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DEFINE_PCI_CONFIG(write, word, u16)
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DEFINE_PCI_CONFIG(write, dword, u32)
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static int conf_space_read(struct pci_dev *dev,
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const struct config_field_entry *entry,
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int offset, u32 *value)
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{
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int ret = 0;
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const struct config_field *field = entry->field;
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*value = 0;
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switch (field->size) {
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case 1:
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if (field->u.b.read)
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ret = field->u.b.read(dev, offset, (u8 *) value,
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entry->data);
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break;
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case 2:
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if (field->u.w.read)
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ret = field->u.w.read(dev, offset, (u16 *) value,
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entry->data);
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break;
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case 4:
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if (field->u.dw.read)
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ret = field->u.dw.read(dev, offset, value, entry->data);
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break;
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}
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return ret;
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}
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static int conf_space_write(struct pci_dev *dev,
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const struct config_field_entry *entry,
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int offset, u32 value)
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{
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int ret = 0;
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const struct config_field *field = entry->field;
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switch (field->size) {
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case 1:
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if (field->u.b.write)
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ret = field->u.b.write(dev, offset, (u8) value,
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entry->data);
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break;
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case 2:
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if (field->u.w.write)
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ret = field->u.w.write(dev, offset, (u16) value,
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entry->data);
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break;
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case 4:
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if (field->u.dw.write)
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ret = field->u.dw.write(dev, offset, value,
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entry->data);
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break;
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}
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return ret;
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}
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static inline u32 get_mask(int size)
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{
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if (size == 1)
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return 0xff;
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else if (size == 2)
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return 0xffff;
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else
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return 0xffffffff;
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}
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static inline int valid_request(int offset, int size)
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{
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/* Validate request (no un-aligned requests) */
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if ((size == 1 || size == 2 || size == 4) && (offset % size) == 0)
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return 1;
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return 0;
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}
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static inline u32 merge_value(u32 val, u32 new_val, u32 new_val_mask,
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int offset)
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{
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if (offset >= 0) {
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new_val_mask <<= (offset * 8);
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new_val <<= (offset * 8);
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} else {
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new_val_mask >>= (offset * -8);
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new_val >>= (offset * -8);
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}
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val = (val & ~new_val_mask) | (new_val & new_val_mask);
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return val;
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}
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static int pcibios_err_to_errno(int err)
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{
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switch (err) {
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case PCIBIOS_SUCCESSFUL:
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return XEN_PCI_ERR_success;
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case PCIBIOS_DEVICE_NOT_FOUND:
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return XEN_PCI_ERR_dev_not_found;
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case PCIBIOS_BAD_REGISTER_NUMBER:
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return XEN_PCI_ERR_invalid_offset;
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case PCIBIOS_FUNC_NOT_SUPPORTED:
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return XEN_PCI_ERR_not_implemented;
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case PCIBIOS_SET_FAILED:
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return XEN_PCI_ERR_access_denied;
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}
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return err;
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}
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int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size,
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u32 *ret_val)
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{
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int err = 0;
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struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
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const struct config_field_entry *cfg_entry;
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const struct config_field *field;
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int req_start, req_end, field_start, field_end;
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/* if read fails for any reason, return 0
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* (as if device didn't respond) */
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u32 value = 0, tmp_val;
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if (unlikely(verbose_request))
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printk(KERN_DEBUG DRV_NAME ": %s: read %d bytes at 0x%x\n",
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pci_name(dev), size, offset);
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if (!valid_request(offset, size)) {
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err = XEN_PCI_ERR_invalid_offset;
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goto out;
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}
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/* Get the real value first, then modify as appropriate */
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switch (size) {
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case 1:
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err = pci_read_config_byte(dev, offset, (u8 *) &value);
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break;
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case 2:
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err = pci_read_config_word(dev, offset, (u16 *) &value);
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break;
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case 4:
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err = pci_read_config_dword(dev, offset, &value);
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break;
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}
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list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
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field = cfg_entry->field;
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req_start = offset;
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req_end = offset + size;
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field_start = OFFSET(cfg_entry);
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field_end = OFFSET(cfg_entry) + field->size;
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if ((req_start >= field_start && req_start < field_end)
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|| (req_end > field_start && req_end <= field_end)) {
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err = conf_space_read(dev, cfg_entry, field_start,
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&tmp_val);
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if (err)
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goto out;
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value = merge_value(value, tmp_val,
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get_mask(field->size),
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field_start - req_start);
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}
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}
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out:
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if (unlikely(verbose_request))
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printk(KERN_DEBUG DRV_NAME ": %s: read %d bytes at 0x%x = %x\n",
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pci_name(dev), size, offset, value);
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*ret_val = value;
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return pcibios_err_to_errno(err);
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}
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int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value)
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{
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int err = 0, handled = 0;
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struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
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const struct config_field_entry *cfg_entry;
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const struct config_field *field;
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u32 tmp_val;
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int req_start, req_end, field_start, field_end;
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if (unlikely(verbose_request))
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printk(KERN_DEBUG
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DRV_NAME ": %s: write request %d bytes at 0x%x = %x\n",
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pci_name(dev), size, offset, value);
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if (!valid_request(offset, size))
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return XEN_PCI_ERR_invalid_offset;
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list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
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field = cfg_entry->field;
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req_start = offset;
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req_end = offset + size;
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field_start = OFFSET(cfg_entry);
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field_end = OFFSET(cfg_entry) + field->size;
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if ((req_start >= field_start && req_start < field_end)
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|| (req_end > field_start && req_end <= field_end)) {
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tmp_val = 0;
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err = xen_pcibk_config_read(dev, field_start,
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field->size, &tmp_val);
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if (err)
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break;
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tmp_val = merge_value(tmp_val, value, get_mask(size),
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req_start - field_start);
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err = conf_space_write(dev, cfg_entry, field_start,
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tmp_val);
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/* handled is set true here, but not every byte
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* may have been written! Properly detecting if
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* every byte is handled is unnecessary as the
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* flag is used to detect devices that need
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* special helpers to work correctly.
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*/
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handled = 1;
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}
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}
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if (!handled && !err) {
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/* By default, anything not specificially handled above is
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* read-only. The permissive flag changes this behavior so
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* that anything not specifically handled above is writable.
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* This means that some fields may still be read-only because
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* they have entries in the config_field list that intercept
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* the write and do nothing. */
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if (dev_data->permissive || permissive) {
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switch (size) {
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case 1:
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err = pci_write_config_byte(dev, offset,
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(u8) value);
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break;
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case 2:
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err = pci_write_config_word(dev, offset,
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(u16) value);
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break;
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case 4:
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err = pci_write_config_dword(dev, offset,
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(u32) value);
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break;
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}
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} else if (!dev_data->warned_on_write) {
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dev_data->warned_on_write = 1;
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dev_warn(&dev->dev, "Driver tried to write to a "
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"read-only configuration space field at offset"
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" 0x%x, size %d. This may be harmless, but if "
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"you have problems with your device:\n"
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"1) see permissive attribute in sysfs\n"
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"2) report problems to the xen-devel "
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"mailing list along with details of your "
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"device obtained from lspci.\n", offset, size);
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}
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}
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return pcibios_err_to_errno(err);
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}
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void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev)
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{
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struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
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struct config_field_entry *cfg_entry, *t;
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const struct config_field *field;
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dev_dbg(&dev->dev, "free-ing dynamically allocated virtual "
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"configuration space fields\n");
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if (!dev_data)
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return;
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list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
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field = cfg_entry->field;
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if (field->clean) {
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field->clean((struct config_field *)field);
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kfree(cfg_entry->data);
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list_del(&cfg_entry->list);
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kfree(cfg_entry);
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}
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}
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}
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void xen_pcibk_config_reset_dev(struct pci_dev *dev)
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{
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struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
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const struct config_field_entry *cfg_entry;
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const struct config_field *field;
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dev_dbg(&dev->dev, "resetting virtual configuration space\n");
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if (!dev_data)
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return;
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list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
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field = cfg_entry->field;
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if (field->reset)
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field->reset(dev, OFFSET(cfg_entry), cfg_entry->data);
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}
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}
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void xen_pcibk_config_free_dev(struct pci_dev *dev)
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{
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struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
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struct config_field_entry *cfg_entry, *t;
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const struct config_field *field;
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dev_dbg(&dev->dev, "free-ing virtual configuration space fields\n");
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if (!dev_data)
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return;
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list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
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list_del(&cfg_entry->list);
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field = cfg_entry->field;
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if (field->release)
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field->release(dev, OFFSET(cfg_entry), cfg_entry->data);
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kfree(cfg_entry);
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}
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}
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int xen_pcibk_config_add_field_offset(struct pci_dev *dev,
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const struct config_field *field,
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unsigned int base_offset)
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{
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int err = 0;
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struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
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struct config_field_entry *cfg_entry;
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void *tmp;
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cfg_entry = kmalloc(sizeof(*cfg_entry), GFP_KERNEL);
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if (!cfg_entry) {
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err = -ENOMEM;
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goto out;
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}
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cfg_entry->data = NULL;
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cfg_entry->field = field;
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cfg_entry->base_offset = base_offset;
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/* silently ignore duplicate fields */
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err = xen_pcibk_field_is_dup(dev, OFFSET(cfg_entry));
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if (err)
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goto out;
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if (field->init) {
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tmp = field->init(dev, OFFSET(cfg_entry));
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if (IS_ERR(tmp)) {
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err = PTR_ERR(tmp);
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goto out;
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}
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cfg_entry->data = tmp;
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}
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dev_dbg(&dev->dev, "added config field at offset 0x%02x\n",
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OFFSET(cfg_entry));
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list_add_tail(&cfg_entry->list, &dev_data->config_fields);
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out:
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if (err)
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kfree(cfg_entry);
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return err;
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}
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/* This sets up the device's virtual configuration space to keep track of
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* certain registers (like the base address registers (BARs) so that we can
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* keep the client from manipulating them directly.
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*/
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int xen_pcibk_config_init_dev(struct pci_dev *dev)
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{
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int err = 0;
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struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
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dev_dbg(&dev->dev, "initializing virtual configuration space\n");
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INIT_LIST_HEAD(&dev_data->config_fields);
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err = xen_pcibk_config_header_add_fields(dev);
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if (err)
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goto out;
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err = xen_pcibk_config_capability_add_fields(dev);
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if (err)
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goto out;
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err = xen_pcibk_config_quirks_init(dev);
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out:
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return err;
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}
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int xen_pcibk_config_init(void)
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{
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return xen_pcibk_config_capability_init();
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}
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