[PATCH 4/4] PCI/PTM: Cache PTM Capability offset

Bjorn Helgaas
2022-09-02T15:26:21Z

From: Bjorn Helgaas <bhelgaas@google.com>

Cache the PTM Capability offset in struct pci_dev so we don't have to
search for it every time we enable/disable/save/restore. No functional
change intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/pcie/ptm.c | 46 ++++++++++++++++--------------------------
include/linux/pci.h | 1 +
2 files changed, 18 insertions(+), 29 deletions(-)

diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c
index 3115601a85ef..8f38ba7b386c 100644
--- a/drivers/pci/pcie/ptm.c
+++ b/drivers/pci/pcie/ptm.c
@@ -31,14 +31,10 @@ static void pci_ptm_info(struct pci_dev *dev)

void pci_disable_ptm(struct pci_dev *dev)
{
- int ptm;
+ u16 ptm = dev->ptm_cap;
u16 ctrl;

- if (!pci_is_pcie(dev))
- return;
-
- ptm = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM);
- if (!ptm)
+ if (!ptm || !dev->ptm_enabled)
return;

pci_read_config_word(dev, ptm + PCI_PTM_CTRL, &ctrl);
@@ -48,14 +44,10 @@ void pci_disable_ptm(struct pci_dev *dev)

void pci_save_ptm_state(struct pci_dev *dev)
{
- int ptm;
+ u16 ptm = dev->ptm_cap;
struct pci_cap_saved_state *save_state;
u16 *cap;

- if (!pci_is_pcie(dev))
- return;
-
- ptm = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM);
if (!ptm)
return;

@@ -69,16 +61,15 @@ void pci_save_ptm_state(struct pci_dev *dev)

void pci_restore_ptm_state(struct pci_dev *dev)
{
+ u16 ptm = dev->ptm_cap;
struct pci_cap_saved_state *save_state;
- int ptm;
u16 *cap;

- if (!pci_is_pcie(dev))
+ if (!ptm)
return;

save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_PTM);
- ptm = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM);
- if (!save_state || !ptm)
+ if (!save_state)
return;

cap = (u16 *)&save_state->cap.data[0];
@@ -95,10 +86,10 @@ void pci_restore_ptm_state(struct pci_dev *dev)

void pci_ptm_init(struct pci_dev *dev)
{
- int pos;
+ struct pci_dev *ups;
+ u16 ptm;
u32 cap, ctrl;
u8 local_clock;
- struct pci_dev *ups;

if (!pci_is_pcie(dev))
return;
@@ -125,13 +116,14 @@ void pci_ptm_init(struct pci_dev *dev)
return;
}

- pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM);
- if (!pos)
+ ptm = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM);
+ dev->ptm_cap = ptm;
+ if (!ptm)
return;

pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_PTM, sizeof(u16));

- pci_read_config_dword(dev, pos + PCI_PTM_CAP, &cap);
+ pci_read_config_dword(dev, ptm + PCI_PTM_CAP, &cap);
local_clock = (cap & PCI_PTM_GRANULARITY_MASK) >> 8;

/*
@@ -156,7 +148,7 @@ void pci_ptm_init(struct pci_dev *dev)
}

ctrl |= dev->ptm_granularity << 8;
- pci_write_config_dword(dev, pos + PCI_PTM_CTRL, ctrl);
+ pci_write_config_dword(dev, ptm + PCI_PTM_CTRL, ctrl);
dev->ptm_enabled = 1;

pci_ptm_info(dev);
@@ -164,18 +156,14 @@ void pci_ptm_init(struct pci_dev *dev)

int pci_enable_ptm(struct pci_dev *dev, u8 *granularity)
{
- int pos;
+ u16 ptm = dev->ptm_cap;
u32 cap, ctrl;
struct pci_dev *ups;

- if (!pci_is_pcie(dev))
+ if (!ptm)
return -EINVAL;

- pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM);
- if (!pos)
- return -EINVAL;
-
- pci_read_config_dword(dev, pos + PCI_PTM_CAP, &cap);
+ pci_read_config_dword(dev, ptm + PCI_PTM_CAP, &cap);
if (!(cap & PCI_PTM_CAP_REQ))
return -EINVAL;

@@ -200,7 +188,7 @@ int pci_enable_ptm(struct pci_dev *dev, u8 *granularity)

ctrl = PCI_PTM_CTRL_ENABLE;
ctrl |= dev->ptm_granularity << 8;
- pci_write_config_dword(dev, pos + PCI_PTM_CTRL, ctrl);
+ pci_write_config_dword(dev, ptm + PCI_PTM_CTRL, ctrl);
dev->ptm_enabled = 1;

pci_ptm_info(dev);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 060af91bafcd..f6c162d06bff 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -475,6 +475,7 @@ struct pci_dev {
unsigned int broken_cmd_compl:1; /* No compl for some cmds */
#endif
#ifdef CONFIG_PCIE_PTM
+ u16 ptm_cap; /* PTM Capability offset */
unsigned int ptm_root:1;
unsigned int ptm_enabled:1;
u8 ptm_granularity;
--
2.25.1