linux-kernel - [PATCH v3 05/10] PCI/PTM: Add pci_disable

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Message-Id: <20220906222351.64760-6-helgaas@kernel.org>
Date:   Tue,  6 Sep 2022 17:23:46 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Kai-Heng Feng <kai.heng.feng@...onical.com>,
        Rajvi Jingar <rajvi.jingar@...ux.intel.com>,
        "Rafael J . Wysocki" <rafael@...nel.org>
Cc:     Koba Ko <koba.ko@...onical.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        "David E . Box" <david.e.box@...ux.intel.com>,
        Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        linux-pci@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Bjorn Helgaas <bhelgaas@...gle.com>
Subject: [PATCH v3 05/10] PCI/PTM: Add pci_disable_ptm() wrapper

From: Bjorn Helgaas <bhelgaas@...gle.com>

Implement pci_disable_ptm() as a wrapper around an internal
__pci_disable_ptm() that we can use during suspend to disable PTM without
clearing dev->ptm_enabled.  A future commit will re-enable PTM during
resume when dev->ptm_enabled is set.

Export pci_disable_ptm(), which *does* clear dev->ptm_enabled, for use by
drivers that want to disable PTM.

Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
---
 drivers/pci/pci.h      | 2 --
 drivers/pci/pcie/ptm.c | 9 ++++++++-
 include/linux/pci.h    | 2 ++
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 785f31086313..91a465460d0f 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -507,11 +507,9 @@ static inline int pci_iov_bus_range(struct pci_bus *bus)
 #ifdef CONFIG_PCIE_PTM
 void pci_save_ptm_state(struct pci_dev *dev);
 void pci_restore_ptm_state(struct pci_dev *dev);
-void pci_disable_ptm(struct pci_dev *dev);
 #else
 static inline void pci_save_ptm_state(struct pci_dev *dev) { }
 static inline void pci_restore_ptm_state(struct pci_dev *dev) { }
-static inline void pci_disable_ptm(struct pci_dev *dev) { }
 #endif
 
 unsigned long pci_cardbus_resource_alignment(struct resource *);
diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c
index ac51cd84793f..762299984469 100644
--- a/drivers/pci/pcie/ptm.c
+++ b/drivers/pci/pcie/ptm.c
@@ -29,7 +29,7 @@ static void pci_ptm_info(struct pci_dev *dev)
 		 dev->ptm_root ? " (root)" : "", clock_desc);
 }
 
-void pci_disable_ptm(struct pci_dev *dev)
+static void __pci_disable_ptm(struct pci_dev *dev)
 {
 	int ptm = dev->ptm_cap;
 	u16 ctrl;
@@ -42,6 +42,13 @@ void pci_disable_ptm(struct pci_dev *dev)
 	pci_write_config_word(dev, ptm + PCI_PTM_CTRL, ctrl);
 }
 
+void pci_disable_ptm(struct pci_dev *dev)
+{
+	__pci_disable_ptm(dev);
+	dev->ptm_enabled = 0;
+}
+EXPORT_SYMBOL(pci_disable_ptm);
+
 void pci_save_ptm_state(struct pci_dev *dev)
 {
 	int ptm = dev->ptm_cap;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 54be939023a3..cb5f796e3319 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1678,10 +1678,12 @@ bool pci_ats_disabled(void);
 
 #ifdef CONFIG_PCIE_PTM
 int pci_enable_ptm(struct pci_dev *dev, u8 *granularity);
+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)
 { return -EINVAL; }
+static inline void pci_disable_ptm(struct pci_dev *dev) { }
 static inline bool pcie_ptm_enabled(struct pci_dev *dev)
 { return false; }
 #endif
-- 
2.25.1