PCI/PTM: Cache PTM Capability offset

Cache the PTM Capability offset instead of searching for it every time we
enable/disable PTM or save/restore PTM state.  No functional change
intended.

Link: https://lore.kernel.org/r/20220909202505.314195-2-helgaas@kernel.org
Tested-by: Rajvi Jingar <rajvi.jingar@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c
index 368a254..85382c1 100644 (file)
--- a/drivers/pci/pcie/ptm.c
+++ b/drivers/pci/pcie/ptm.c
@@ -31,13 +31,9 @@ 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)
                return;
 
@@ -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];
@@ -87,7 +78,7 @@ void pci_restore_ptm_state(struct pci_dev *dev)
 
 void pci_ptm_init(struct pci_dev *dev)
 {
-       int pos;
+       u16 ptm;
        u32 cap, ctrl;
        u8 local_clock;
        struct pci_dev *ups;
@@ -117,13 +108,14 @@ 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);
+       if (!ptm)
                return;
 
+       dev->ptm_cap = ptm;
        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;
 
        /*
@@ -148,7 +140,7 @@ 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);
@@ -156,18 +148,19 @@ void pci_ptm_init(struct pci_dev *dev)
 
 int pci_enable_ptm(struct pci_dev *dev, u8 *granularity)
 {
-       int pos;
+       u16 ptm;
        u32 cap, ctrl;
        struct pci_dev *ups;
 
        if (!pci_is_pcie(dev))
                return -EINVAL;
 
-       pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM);
-       if (!pos)
+       ptm = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM);
+       if (!ptm)
                return -EINVAL;
 
-       pci_read_config_dword(dev, pos + PCI_PTM_CAP, &cap);
+       dev->ptm_cap = ptm;
+       pci_read_config_dword(dev, ptm + PCI_PTM_CAP, &cap);
        if (!(cap & PCI_PTM_CAP_REQ))
                return -EINVAL;
 
@@ -192,7 +185,7 @@ 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 060af91..54be939 100644 (file)
--- 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 */
        unsigned int    ptm_root:1;
        unsigned int    ptm_enabled:1;
        u8              ptm_granularity;