Commit 72b3a644 authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

Merge branch 'pci/ptm' 

- Save/restore Precision Time Measurement Capability for suspend/resume
  (David E. Box)

- Disable PTM during suspend to save power (David E. Box)

* pci/ptm:
  PCI: Disable PTM during suspend to save power
  PCI/PTM: Save/restore Precision Time Measurement Capability for suspend/resume
parents ff163da9 a697f072

drivers/pci/pci.c

+26 −1
Original line number Diff line number Diff line
@@ -1561,6 +1561,7 @@ int pci_save_state(struct pci_dev *dev) 
	pci_save_aspm_l1ss_state(dev);

	pci_save_dpc_state(dev);

	pci_save_aer_state(dev);

	pci_save_ptm_state(dev);

	return pci_save_vc_state(dev);

}

EXPORT_SYMBOL(pci_save_state);
@@ -1673,6 +1674,7 @@ void pci_restore_state(struct pci_dev *dev) 
	pci_restore_vc_state(dev);

	pci_restore_rebar_state(dev);

	pci_restore_dpc_state(dev);

	pci_restore_ptm_state(dev);



	pci_aer_clear_status(dev);

	pci_restore_aer_state(dev);
@@ -2602,12 +2604,24 @@ int pci_prepare_to_sleep(struct pci_dev *dev) 
	if (target_state == PCI_POWER_ERROR)

		return -EIO;



	/*

	 * There are systems (for example, Intel mobile chips since Coffee

	 * Lake) where the power drawn while suspended can be significantly

	 * reduced by disabling PTM on PCIe root ports as this allows the

	 * port to enter a lower-power PM state and the SoC to reach a

	 * lower-power idle state as a whole.

	 */

	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)

		pci_disable_ptm(dev);



	pci_enable_wake(dev, target_state, wakeup);



	error = pci_set_power_state(dev, target_state);



	if (error)

	if (error) {

		pci_enable_wake(dev, target_state, false);

		pci_restore_ptm_state(dev);

	}



	return error;

}
@@ -2645,12 +2659,23 @@ int pci_finish_runtime_suspend(struct pci_dev *dev) 


	dev->runtime_d3cold = target_state == PCI_D3cold;



	/*

	 * There are systems (for example, Intel mobile chips since Coffee

	 * Lake) where the power drawn while suspended can be significantly

	 * reduced by disabling PTM on PCIe root ports as this allows the

	 * port to enter a lower-power PM state and the SoC to reach a

	 * lower-power idle state as a whole.

	 */

	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)

		pci_disable_ptm(dev);



	__pci_enable_wake(dev, target_state, pci_dev_run_wake(dev));



	error = pci_set_power_state(dev, target_state);



	if (error) {

		pci_enable_wake(dev, target_state, false);

		pci_restore_ptm_state(dev);

		dev->runtime_d3cold = false;

	}

drivers/pci/pci.h

+10 −0
Original line number Diff line number Diff line
@@ -524,6 +524,16 @@ static inline int pci_iov_bus_range(struct pci_bus *bus) 


#endif /* CONFIG_PCI_IOV */



#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 *);



static inline resource_size_t pci_resource_alignment(struct pci_dev *dev,

drivers/pci/pcie/ptm.c

+60 −0
Original line number Diff line number Diff line
@@ -29,6 +29,64 @@ static void pci_ptm_info(struct pci_dev *dev) 
		 dev->ptm_root ? " (root)" : "", clock_desc);

}



void pci_disable_ptm(struct pci_dev *dev)

{

	int ptm;

	u16 ctrl;



	if (!pci_is_pcie(dev))

		return;



	ptm = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM);

	if (!ptm)

		return;



	pci_read_config_word(dev, ptm + PCI_PTM_CTRL, &ctrl);

	ctrl &= ~(PCI_PTM_CTRL_ENABLE | PCI_PTM_CTRL_ROOT);

	pci_write_config_word(dev, ptm + PCI_PTM_CTRL, ctrl);

}



void pci_save_ptm_state(struct pci_dev *dev)

{

	int ptm;

	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;



	save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_PTM);

	if (!save_state) {

		pci_err(dev, "no suspend buffer for PTM\n");

		return;

	}



	cap = (u16 *)&save_state->cap.data[0];

	pci_read_config_word(dev, ptm + PCI_PTM_CTRL, cap);

}



void pci_restore_ptm_state(struct pci_dev *dev)

{

	struct pci_cap_saved_state *save_state;

	int ptm;

	u16 *cap;



	if (!pci_is_pcie(dev))

		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)

		return;



	cap = (u16 *)&save_state->cap.data[0];

	pci_write_config_word(dev, ptm + PCI_PTM_CTRL, *cap);

}



void pci_ptm_init(struct pci_dev *dev)

{

	int pos;
@@ -65,6 +123,8 @@ void pci_ptm_init(struct pci_dev *dev) 
	if (!pos)

		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);

	local_clock = (cap & PCI_PTM_GRANULARITY_MASK) >> 8;

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