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PCI/ASPM: Move pci_save_ltr_state() to aspm.c

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Even when CONFIG_PCIEASPM is not set, we save and restore the LTR
Capability so that if ASPM L1.2 and LTR were configured by the platform,
ASPM L1.2 will still work after suspend/resume, when that platform
configuration may be lost. See dbbfadf231 ("PCI/ASPM: Save LTR Capability
for suspend/resume").

Since ASPM L1.2 depends on the LTR Capability, move the save/restore code
to the part of aspm.c that is always compiled regardless of
CONFIG_PCIEASPM.  No functional change intended.

Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20240128233212.1139663-5-david.e.box@linux.intel.com
[bhelgaas: commit log, reorder to make this a pure move]
Link: https://lore.kernel.org/r/20240223205851.114931-4-helgaas@kernel.org
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
David E. Box 2024-02-23 14:58:49 -06:00 committed by Bjorn Helgaas
parent f3994bba82
commit 1e11b5494c
3 changed files with 45 additions and 40 deletions
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40
drivers/pci/pci.c
View File

@ -1689,46 +1689,6 @@ static void pci_restore_pcix_state(struct pci_dev *dev)
pci_write_config_word(dev, pos + PCI_X_CMD, cap[i++]);
}
static void pci_save_ltr_state(struct pci_dev *dev)
{
int ltr;
struct pci_cap_saved_state *save_state;
u32 *cap;
if (!pci_is_pcie(dev))
return;
ltr = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_LTR);
if (!ltr)
return;
save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_LTR);
if (!save_state) {
pci_err(dev, "no suspend buffer for LTR; ASPM issues possible after resume\n");
return;
}
/* Some broken devices only support dword access to LTR */
cap = &save_state->cap.data[0];
pci_read_config_dword(dev, ltr + PCI_LTR_MAX_SNOOP_LAT, cap);
}
static void pci_restore_ltr_state(struct pci_dev *dev)
{
struct pci_cap_saved_state *save_state;
int ltr;
u32 *cap;
save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_LTR);
ltr = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_LTR);
if (!save_state || !ltr)
return;
/* Some broken devices only support dword access to LTR */
cap = &save_state->cap.data[0];
pci_write_config_dword(dev, ltr + PCI_LTR_MAX_SNOOP_LAT, *cap);
}
/**
* pci_save_state - save the PCI configuration space of a device before
* suspending

5
drivers/pci/pci.h
View File

@ -567,6 +567,11 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
bool pcie_wait_for_link(struct pci_dev *pdev, bool active);
int pcie_retrain_link(struct pci_dev *pdev, bool use_lt);
/* ASPM-related functionality we need even without CONFIG_PCIEASPM */
void pci_save_ltr_state(struct pci_dev *dev);
void pci_restore_ltr_state(struct pci_dev *dev);
#ifdef CONFIG_PCIEASPM
void pcie_aspm_init_link_state(struct pci_dev *pdev);
void pcie_aspm_exit_link_state(struct pci_dev *pdev);

40
drivers/pci/pcie/aspm.c
View File

@ -24,6 +24,46 @@
#include "../pci.h"
void pci_save_ltr_state(struct pci_dev *dev)
{
int ltr;
struct pci_cap_saved_state *save_state;
u32 *cap;
if (!pci_is_pcie(dev))
return;
ltr = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_LTR);
if (!ltr)
return;
save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_LTR);
if (!save_state) {
pci_err(dev, "no suspend buffer for LTR; ASPM issues possible after resume\n");
return;
}
/* Some broken devices only support dword access to LTR */
cap = &save_state->cap.data[0];
pci_read_config_dword(dev, ltr + PCI_LTR_MAX_SNOOP_LAT, cap);
}
void pci_restore_ltr_state(struct pci_dev *dev)
{
struct pci_cap_saved_state *save_state;
int ltr;
u32 *cap;
save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_LTR);
ltr = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_LTR);
if (!save_state || !ltr)
return;
/* Some broken devices only support dword access to LTR */
cap = &save_state->cap.data[0];
pci_write_config_dword(dev, ltr + PCI_LTR_MAX_SNOOP_LAT, *cap);
}
#ifdef CONFIG_PCIEASPM
#ifdef MODULE_PARAM_PREFIX