Merge branch 'pci/ptm'

- Leave Precision Time Measurement disabled until a driver enables it to
  avoid PCIe errors (Mika Westerberg)

* pci/ptm:
  PCI/PTM: Do not enable PTM automatically for Root and Switch Upstream Ports
  PCI/PTM: Drop pci_enable_ptm() granularity parameter

6 files changed, 48 insertions, 43 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index ebf48feffb30..b35c4e4ecd2a 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -5028,7 +5028,7 @@ static int ice_init(struct ice_pf *pf)
 	}
 
 	if (pf->hw.mac_type == ICE_MAC_E830) {
-		err = pci_enable_ptm(pf->pdev, NULL);
+		err = pci_enable_ptm(pf->pdev);
 		if (err)
 			dev_dbg(dev, "PCIe PTM not supported by PCIe bus/controller\n");
 	}
diff --git a/drivers/net/ethernet/intel/idpf/idpf_main.c b/drivers/net/ethernet/intel/idpf/idpf_main.c
index 0dd741dcfcdb..ab3c409e587b 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_main.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_main.c
@@ -257,7 +257,7 @@ static int idpf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto err_free;
 	}
 
-	err = pci_enable_ptm(pdev, NULL);
+	err = pci_enable_ptm(pdev);
 	if (err)
 		pci_dbg(pdev, "PCIe PTM is not supported by PCIe bus/controller\n");
 
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 27e5c2109138..b030acf94ac4 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -7123,7 +7123,7 @@ static int igc_probe(struct pci_dev *pdev,
 	if (err)
 		goto err_pci_reg;
 
-	err = pci_enable_ptm(pdev, NULL);
+	err = pci_enable_ptm(pdev);
 	if (err < 0)
 		dev_info(&pdev->dev, "PCIe PTM not supported by PCIe bus/controller\n");
 
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
index fdc3ba20912e..0b94d4ed0ef6 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
@@ -960,7 +960,7 @@ static int mlx5_pci_init(struct mlx5_core_dev *dev, struct pci_dev *pdev,
 
 	mlx5_pci_vsc_init(dev);
 
-	pci_enable_ptm(pdev, NULL);
+	pci_enable_ptm(pdev);
 
 	return 0;
 
diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c
index 91a598ed534c..a41ffd1914de 100644
--- a/drivers/pci/pcie/ptm.c
+++ b/drivers/pci/pcie/ptm.c
@@ -52,6 +52,7 @@ void pci_ptm_init(struct pci_dev *dev)
 		return;
 
 	dev->ptm_cap = ptm;
+	atomic_set(&dev->ptm_enable_cnt, 0);
 	pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_PTM, sizeof(u32));
 
 	pci_read_config_dword(dev, ptm + PCI_PTM_CAP, &cap);
@@ -85,10 +86,6 @@ void pci_ptm_init(struct pci_dev *dev)
 		dev->ptm_responder = 1;
 	if (cap & PCI_PTM_CAP_REQ)
 		dev->ptm_requester = 1;
-
-	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
-	    pci_pcie_type(dev) == PCI_EXP_TYPE_UPSTREAM)
-		pci_enable_ptm(dev, NULL);
 }
 
 void pci_save_ptm_state(struct pci_dev *dev)
@@ -129,26 +126,11 @@ void pci_restore_ptm_state(struct pci_dev *dev)
 static int __pci_enable_ptm(struct pci_dev *dev)
 {
 	u16 ptm = dev->ptm_cap;
-	struct pci_dev *ups;
 	u32 ctrl;
 
 	if (!ptm)
 		return -EINVAL;
 
-	/*
-	 * A device uses local PTM Messages to request time information
-	 * from a PTM Root that's farther upstream.  Every device along the
-	 * path must support PTM and have it enabled so it can handle the
-	 * messages.  Therefore, if this device is not a PTM Root, the
-	 * upstream link partner must have PTM enabled before we can enable
-	 * PTM.
-	 */
-	if (!dev->ptm_root) {
-		ups = pci_upstream_ptm(dev);
-		if (!ups || !ups->ptm_enabled)
-			return -EINVAL;
-	}
-
 	switch (pci_pcie_type(dev)) {
 	case PCI_EXP_TYPE_ROOT_PORT:
 		if (!dev->ptm_root)
@@ -182,27 +164,46 @@ static int __pci_enable_ptm(struct pci_dev *dev)
 /**
  * pci_enable_ptm() - Enable Precision Time Measurement
  * @dev: PCI device
- * @granularity: pointer to return granularity
  *
- * Enable Precision Time Measurement for @dev.  If successful and
- * @granularity is non-NULL, return the Effective Granularity.
+ * Enable Precision Time Measurement for @dev.
  *
  * Return: zero if successful, or -EINVAL if @dev lacks a PTM Capability or
  * is not a PTM Root and lacks an upstream path of PTM-enabled devices.
  */
-int pci_enable_ptm(struct pci_dev *dev, u8 *granularity)
+int pci_enable_ptm(struct pci_dev *dev)
 {
 	int rc;
 	char clock_desc[8];
 
-	rc = __pci_enable_ptm(dev);
-	if (rc)
-		return rc;
+	/*
+	 * A device uses local PTM Messages to request time information
+	 * from a PTM Root that's farther upstream. Every device along
+	 * the path must support PTM and have it enabled so it can
+	 * handle the messages. Therefore, if this device is not a PTM
+	 * Root, the upstream link partner must have PTM enabled before
+	 * we can enable PTM.
+	 */
+	if (!dev->ptm_root) {
+		struct pci_dev *parent;
+
+		parent = pci_upstream_ptm(dev);
+		if (!parent)
+			return -EINVAL;
+		/* Enable PTM for the parent */
+		rc = pci_enable_ptm(parent);
+		if (rc)
+			return rc;
+	}
 
-	dev->ptm_enabled = 1;
+	/* Already enabled? */
+	if (atomic_inc_return(&dev->ptm_enable_cnt) > 1)
+		return 0;
 
-	if (granularity)
-		*granularity = dev->ptm_granularity;
+	rc = __pci_enable_ptm(dev);
+	if (rc) {
+		atomic_dec(&dev->ptm_enable_cnt);
+		return rc;
+	}
 
 	switch (dev->ptm_granularity) {
 	case 0:
@@ -244,27 +245,31 @@ static void __pci_disable_ptm(struct pci_dev *dev)
  */
 void pci_disable_ptm(struct pci_dev *dev)
 {
-	if (dev->ptm_enabled) {
+	struct pci_dev *parent;
+
+	if (atomic_dec_and_test(&dev->ptm_enable_cnt))
 		__pci_disable_ptm(dev);
-		dev->ptm_enabled = 0;
-	}
+
+	parent = pci_upstream_ptm(dev);
+	if (parent)
+		pci_disable_ptm(parent);
 }
 EXPORT_SYMBOL(pci_disable_ptm);
 
 /*
- * Disable PTM, but preserve dev->ptm_enabled so we silently re-enable it on
+ * Disable PTM, but preserve dev->ptm_enable_cnt so we silently re-enable it on
  * resume if necessary.
  */
 void pci_suspend_ptm(struct pci_dev *dev)
 {
-	if (dev->ptm_enabled)
+	if (atomic_read(&dev->ptm_enable_cnt))
 		__pci_disable_ptm(dev);
 }
 
 /* If PTM was enabled before suspend, re-enable it when resuming */
 void pci_resume_ptm(struct pci_dev *dev)
 {
-	if (dev->ptm_enabled)
+	if (atomic_read(&dev->ptm_enable_cnt))
 		__pci_enable_ptm(dev);
 }
 
@@ -273,7 +278,7 @@ bool pcie_ptm_enabled(struct pci_dev *dev)
 	if (!dev)
 		return false;
 
-	return dev->ptm_enabled;
+	return atomic_read(&dev->ptm_enable_cnt);
 }
 EXPORT_SYMBOL(pcie_ptm_enabled);
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 482dd8460dd9..47c5b0c09ffb 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -518,7 +518,7 @@ struct pci_dev {
 	unsigned int	ptm_root:1;
 	unsigned int	ptm_responder:1;
 	unsigned int	ptm_requester:1;
-	unsigned int	ptm_enabled:1;
+	atomic_t	ptm_enable_cnt;
 	u8		ptm_granularity;
 #endif
 #ifdef CONFIG_PCI_MSI
@@ -1973,11 +1973,11 @@ struct pci_ptm_debugfs {
 };
 
 #ifdef CONFIG_PCIE_PTM
-int pci_enable_ptm(struct pci_dev *dev, u8 *granularity);
+int pci_enable_ptm(struct pci_dev *dev);
 void pci_disable_ptm(struct pci_dev *dev);
 bool pcie_ptm_enabled(struct pci_dev *dev);
 #else
-static inline int pci_enable_ptm(struct pci_dev *dev, u8 *granularity)
+static inline int pci_enable_ptm(struct pci_dev *dev)
 { return -EINVAL; }
 static inline void pci_disable_ptm(struct pci_dev *dev) { }
 static inline bool pcie_ptm_enabled(struct pci_dev *dev)