/*
* PCI Backend - Functions for creating a virtual configuration space for
* exported PCI Devices.
* It's dangerous to allow PCI Driver Domains to change their
* device's resources (memory, i/o ports, interrupts). We need to
* restrict changes to certain PCI Configuration registers:
* BARs, INTERRUPT_PIN, most registers in the header...
*
* Author: Ryan Wilson <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include "pciback.h"
#include "conf_space.h"
#include "conf_space_quirks.h"
static bool permissive;
module_param(permissive, bool, 0644);
/* This is where xen_pcibk_read_config_byte, xen_pcibk_read_config_word,
* xen_pcibk_write_config_word, and xen_pcibk_write_config_byte are created. */
#define DEFINE_PCI_CONFIG(op, size, type) \
int xen_pcibk_##op##_config_##size \
(struct pci_dev *dev, int offset, type value, void *data) \
{ \
return pci_##op##_config_##size(dev, offset, value); \
}
DEFINE_PCI_CONFIG(read, byte, u8 *)
DEFINE_PCI_CONFIG(read, word, u16 *)
DEFINE_PCI_CONFIG(read, dword, u32 *)
DEFINE_PCI_CONFIG(write, byte, u8)
DEFINE_PCI_CONFIG(write, word, u16)
DEFINE_PCI_CONFIG(write, dword, u32)
static int conf_space_read(struct pci_dev *dev,
const struct config_field_entry *entry,
int offset, u32 *value)
{
int ret = 0;
const struct config_field *field = entry->field;
*value = 0;
switch (field->size) {
case 1:
if (field->u.b.read)
ret = field->u.b.read(dev, offset, (u8 *) value,
entry->data);
break;
case 2:
if (field->u.w.read)
ret = field->u.w.read(dev, offset, (u16 *) value,
entry->data);
break;
case 4:
if (field->u.dw.read)
ret = field->u.dw.read(dev, offset, value, entry->data);
break;
}
return ret;
}
static int conf_space_write(struct pci_dev *dev,
const struct config_field_entry *entry,
int offset, u32 value)
{
int ret = 0;
const struct config_field *field = entry->field;
switch (field->size) {
case 1:
if (field->u.b.write)
ret = field->u.b.write(dev, offset, (u8) value,
entry->data);
break;
case 2:
if (field->u.w.write)
ret = field->u.w.write(dev, offset, (u16) value,
entry->data);
break;
case 4:
if (field->u.dw.write)
ret = field->u.dw.write(dev, offset, value,
entry->data);
break;
}
return ret;
}
static inline u32 get_mask(int size)
{
if (size == 1)
return 0xff;
else if (size == 2)
return 0xffff;
else
return 0xffffffff;
}
static inline int valid_request(int offset, int size)
{
/* Validate request (no un-aligned requests) */
if ((size == 1 || size == 2 || size == 4) && (offset % size) == 0)
return 1;
return 0;
}
static inline u32 merge_value(u32 val, u32 new_val, u32 new_val_mask,
int offset)
{
if (offset >= 0) {
new_val_mask <<= (offset * 8);
new_val <<= (offset * 8);
} else {
new_val_mask >>= (offset * -8);
new_val >>= (offset * -8);
}
val = (val & ~new_val_mask) | (new_val & new_val_mask);
return val;
}
static int xen_pcibios_err_to_errno(int err)
{
switch (err) {
case PCIBIOS_SUCCESSFUL:
return XEN_PCI_ERR_success;
case PCIBIOS_DEVICE_NOT_FOUND:
return XEN_PCI_ERR_dev_not_found;
case PCIBIOS_BAD_REGISTER_NUMBER:
return XEN_PCI_ERR_invalid_offset;
case PCIBIOS_FUNC_NOT_SUPPORTED:
return XEN_PCI_ERR_not_implemented;
case PCIBIOS_SET_FAILED:
return XEN_PCI_ERR_access_denied;
}
return err;
}
int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size,
u32 *ret_val)
{
int err = 0;
struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
const struct config_field_entry *cfg_entry;
const struct config_field *field;
int req_start, req_end, field_start, field_end;
/* if read fails for any reason, return 0
* (as if device didn't respond) */
u32 value = 0, tmp_val;
if (unlikely(verbose_request))
printk(KERN_DEBUG DRV_NAME ": %s: read %d bytes at 0x%x\n",
pci_name(dev), size, offset);
if (!valid_request(offset, size)) {
err = XEN_PCI_ERR_invalid_offset;
goto out;
}
/* Get the real value first, then modify as appropriate */
switch (size) {
case 1:
err = pci_read_config_byte(dev, offset, (u8 *) &value);
break;
case 2:
err = pci_read_config_word(dev, offset, (u16 *) &value);
break;
case 4:
err = pci_read_config_dword(dev, offset, &value);
break;
}
list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
field = cfg_entry->field;
req_start = offset;
req_end = offset + size;
field_start = OFFSET(cfg_entry);
field_end = OFFSET(cfg_entry) + field->size;
if ((req_start >= field_start && req_start < field_end)
|| (req_end > field_start && req_end <= field_end)) {
err = conf_space_read(dev, cfg_entry, field_start,
&tmp_val);
if (err)
goto out;
value = merge_value(value, tmp_val,
get_mask(field->size),
field_start - req_start);
}
}
out:
if (unlikely(verbose_request))
printk(KERN_DEBUG DRV_NAME ": %s: read %d bytes at 0x%x = %x\n",
pci_name(dev), size, offset, value);
*ret_val = value;
return xen_pcibios_err_to_errno(err);
}
int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value)
{
int err = 0, handled = 0;
struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
const struct config_field_entry *cfg_entry;
const struct config_field *field;
u32 tmp_val;
int req_start, req_end, field_start, field_end;
if (unlikely(verbose_request))
printk(KERN_DEBUG
DRV_NAME ": %s: write request %d bytes at 0x%x = %x\n",
pci_name(dev), size, offset, value);
if (!valid_request(offset, size))
return XEN_PCI_ERR_invalid_offset;
list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
field = cfg_entry->field;
req_start = offset;
req_end = offset + size;
field_start = OFFSET(cfg_entry);
field_end = OFFSET(cfg_entry) + field->size;
if ((req_start >= field_start && req_start < field_end)
|| (req_end > field_start && req_end <= field_end)) {
tmp_val = 0;
err = xen_pcibk_config_read(dev, field_start,
field->size, &tmp_val);
if (err)
break;
tmp_val = merge_value(tmp_val, value, get_mask(size),
req_start - field_start);
err = conf_space_write(dev, cfg_entry, field_start,
tmp_val);
/* handled is set true here, but not every byte
* may have been written! Properly detecting if
* every byte is handled is unnecessary as the
* flag is used to detect devices that need
* special helpers to work correctly.
*/
handled = 1;
}
}
if (!handled && !err) {
/* By default, anything not specificially handled above is
* read-only. The permissive flag changes this behavior so
* that anything not specifically handled above is writable.
* This means that some fields may still be read-only because
* they have entries in the config_field list that intercept
* the write and do nothing. */
if (dev_data->permissive || permissive) {
switch (size) {
case 1:
err = pci_write_config_byte(dev, offset,
(u8) value);
break;
case 2:
err = pci_write_config_word(dev, offset,
(u16) value);
break;
case 4:
err = pci_write_config_dword(dev, offset,
(u32) value);
break;
}
} else if (!dev_data->warned_on_write) {
dev_data->warned_on_write = 1;
dev_warn(&dev->dev, "Driver tried to write to a "
"read-only configuration space field at offset"
" 0x%x, size %d. This may be harmless, but if "
"you have problems with your device:\n"
"1) see permissive attribute in sysfs\n"
"2) report problems to the xen-devel "
"mailing list along with details of your "
"device obtained from lspci.\n", offset, size);
}
}
return xen_pcibios_err_to_errno(err);
}
void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev)
{
struct xen_pcibk_d
