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PCI: only save/restore existent registers in the PCIe capability
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PCIe 1.1 base neither requires the endpoint to implement the entire
PCIe capability structure nor specifies default values of registers
that are not implemented by the device. So we only save and restore
registers that must be implemented by different device types if the
device PCIe capability version is 1.

PCIe 1.1 Capability Structure Expansion ECN and PCIe 2.0 requires
all registers in the PCIe capability to be either implemented or
hardwired to 0. Their PCIe capability version is 2.

Signed-off-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
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Yu Zhao authored and Jesse Barnes committed Apr 22, 2009
1 parent b10ceb5 commit 1b6b8ce
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Showing 2 changed files with 57 additions and 14 deletions.
70 changes: 56 additions & 14 deletions drivers/pci/pci.c
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Original file line number Diff line number Diff line change
Expand Up @@ -681,11 +681,34 @@ EXPORT_SYMBOL(pci_choose_state);

#define PCI_EXP_SAVE_REGS 7

#define pcie_cap_has_devctl(type, flags) 1
#define pcie_cap_has_lnkctl(type, flags) \
((flags & PCI_EXP_FLAGS_VERS) > 1 || \
(type == PCI_EXP_TYPE_ROOT_PORT || \
type == PCI_EXP_TYPE_ENDPOINT || \
type == PCI_EXP_TYPE_LEG_END))
#define pcie_cap_has_sltctl(type, flags) \
((flags & PCI_EXP_FLAGS_VERS) > 1 || \
((type == PCI_EXP_TYPE_ROOT_PORT) || \
(type == PCI_EXP_TYPE_DOWNSTREAM && \
(flags & PCI_EXP_FLAGS_SLOT))))
#define pcie_cap_has_rtctl(type, flags) \
((flags & PCI_EXP_FLAGS_VERS) > 1 || \
(type == PCI_EXP_TYPE_ROOT_PORT || \
type == PCI_EXP_TYPE_RC_EC))
#define pcie_cap_has_devctl2(type, flags) \
((flags & PCI_EXP_FLAGS_VERS) > 1)
#define pcie_cap_has_lnkctl2(type, flags) \
((flags & PCI_EXP_FLAGS_VERS) > 1)
#define pcie_cap_has_sltctl2(type, flags) \
((flags & PCI_EXP_FLAGS_VERS) > 1)

static int pci_save_pcie_state(struct pci_dev *dev)
{
int pos, i = 0;
struct pci_cap_saved_state *save_state;
u16 *cap;
u16 flags;

pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
if (pos <= 0)
Expand All @@ -698,13 +721,22 @@ static int pci_save_pcie_state(struct pci_dev *dev)
}
cap = (u16 *)&save_state->data[0];

pci_read_config_word(dev, pos + PCI_EXP_DEVCTL, &cap[i++]);
pci_read_config_word(dev, pos + PCI_EXP_LNKCTL, &cap[i++]);
pci_read_config_word(dev, pos + PCI_EXP_SLTCTL, &cap[i++]);
pci_read_config_word(dev, pos + PCI_EXP_RTCTL, &cap[i++]);
pci_read_config_word(dev, pos + PCI_EXP_DEVCTL2, &cap[i++]);
pci_read_config_word(dev, pos + PCI_EXP_LNKCTL2, &cap[i++]);
pci_read_config_word(dev, pos + PCI_EXP_SLTCTL2, &cap[i++]);
pci_read_config_word(dev, pos + PCI_EXP_FLAGS, &flags);

if (pcie_cap_has_devctl(dev->pcie_type, flags))
pci_read_config_word(dev, pos + PCI_EXP_DEVCTL, &cap[i++]);
if (pcie_cap_has_lnkctl(dev->pcie_type, flags))
pci_read_config_word(dev, pos + PCI_EXP_LNKCTL, &cap[i++]);
if (pcie_cap_has_sltctl(dev->pcie_type, flags))
pci_read_config_word(dev, pos + PCI_EXP_SLTCTL, &cap[i++]);
if (pcie_cap_has_rtctl(dev->pcie_type, flags))
pci_read_config_word(dev, pos + PCI_EXP_RTCTL, &cap[i++]);
if (pcie_cap_has_devctl2(dev->pcie_type, flags))
pci_read_config_word(dev, pos + PCI_EXP_DEVCTL2, &cap[i++]);
if (pcie_cap_has_lnkctl2(dev->pcie_type, flags))
pci_read_config_word(dev, pos + PCI_EXP_LNKCTL2, &cap[i++]);
if (pcie_cap_has_sltctl2(dev->pcie_type, flags))
pci_read_config_word(dev, pos + PCI_EXP_SLTCTL2, &cap[i++]);

return 0;
}
Expand All @@ -714,20 +746,30 @@ static void pci_restore_pcie_state(struct pci_dev *dev)
int i = 0, pos;
struct pci_cap_saved_state *save_state;
u16 *cap;
u16 flags;

save_state = pci_find_saved_cap(dev, PCI_CAP_ID_EXP);
pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
if (!save_state || pos <= 0)
return;
cap = (u16 *)&save_state->data[0];

pci_write_config_word(dev, pos + PCI_EXP_DEVCTL, cap[i++]);
pci_write_config_word(dev, pos + PCI_EXP_LNKCTL, cap[i++]);
pci_write_config_word(dev, pos + PCI_EXP_SLTCTL, cap[i++]);
pci_write_config_word(dev, pos + PCI_EXP_RTCTL, cap[i++]);
pci_write_config_word(dev, pos + PCI_EXP_DEVCTL2, cap[i++]);
pci_write_config_word(dev, pos + PCI_EXP_LNKCTL2, cap[i++]);
pci_write_config_word(dev, pos + PCI_EXP_SLTCTL2, cap[i++]);
pci_read_config_word(dev, pos + PCI_EXP_FLAGS, &flags);

if (pcie_cap_has_devctl(dev->pcie_type, flags))
pci_write_config_word(dev, pos + PCI_EXP_DEVCTL, cap[i++]);
if (pcie_cap_has_lnkctl(dev->pcie_type, flags))
pci_write_config_word(dev, pos + PCI_EXP_LNKCTL, cap[i++]);
if (pcie_cap_has_sltctl(dev->pcie_type, flags))
pci_write_config_word(dev, pos + PCI_EXP_SLTCTL, cap[i++]);
if (pcie_cap_has_rtctl(dev->pcie_type, flags))
pci_write_config_word(dev, pos + PCI_EXP_RTCTL, cap[i++]);
if (pcie_cap_has_devctl2(dev->pcie_type, flags))
pci_write_config_word(dev, pos + PCI_EXP_DEVCTL2, cap[i++]);
if (pcie_cap_has_lnkctl2(dev->pcie_type, flags))
pci_write_config_word(dev, pos + PCI_EXP_LNKCTL2, cap[i++]);
if (pcie_cap_has_sltctl2(dev->pcie_type, flags))
pci_write_config_word(dev, pos + PCI_EXP_SLTCTL2, cap[i++]);
}


Expand Down
1 change: 1 addition & 0 deletions include/linux/pci_regs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -376,6 +376,7 @@
#define PCI_EXP_TYPE_DOWNSTREAM 0x6 /* Downstream Port */
#define PCI_EXP_TYPE_PCI_BRIDGE 0x7 /* PCI/PCI-X Bridge */
#define PCI_EXP_TYPE_RC_END 0x9 /* Root Complex Integrated Endpoint */
#define PCI_EXP_TYPE_RC_EC 0x10 /* Root Complex Event Collector */
#define PCI_EXP_FLAGS_SLOT 0x0100 /* Slot implemented */
#define PCI_EXP_FLAGS_IRQ 0x3e00 /* Interrupt message number */
#define PCI_EXP_DEVCAP 4 /* Device capabilities */
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