Commit 69139244 authored by Amey Narkhede's avatar Amey Narkhede Committed by Bjorn Helgaas
Browse files

PCI: Cache PCIe Device Capabilities register 

Add a new member called devcap in struct pci_dev for caching the PCIe
Device Capabilities register to avoid reading PCI_EXP_DEVCAP multiple
times.

Refactor pcie_has_flr() to use cached device capabilities.

Link: https://lore.kernel.org/r/20210817180500.1253-2-ameynarkhede03@gmail.com


Signed-off-by: default avatarAmey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarRaphael Norwitz <raphael.norwitz@nutanix.com>
parent e73f0f0e

drivers/pci/pci.c

+2 −4
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#include <linux/vmalloc.h>

#include <asm/dma.h>

#include <linux/aer.h>

#include <linux/bitfield.h>

#include "pci.h"



DEFINE_MUTEX(pci_slot_mutex);
@@ -4630,13 +4631,10 @@ EXPORT_SYMBOL(pci_wait_for_pending_transaction); 
 */

bool pcie_has_flr(struct pci_dev *dev)

{

	u32 cap;



	if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)

		return false;



	pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);

	return cap & PCI_EXP_DEVCAP_FLR;

	return FIELD_GET(PCI_EXP_DEVCAP_FLR, dev->devcap) == 1;

}

EXPORT_SYMBOL_GPL(pcie_has_flr);

drivers/pci/probe.c

+3 −2
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/hypervisor.h>

#include <linux/irqdomain.h>

#include <linux/pm_runtime.h>

#include <linux/bitfield.h>

#include "pci.h"



#define CARDBUS_LATENCY_TIMER	176	/* secondary latency timer */
@@ -1498,8 +1499,8 @@ void set_pcie_port_type(struct pci_dev *pdev) 
	pdev->pcie_cap = pos;

	pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, &reg16);

	pdev->pcie_flags_reg = reg16;

	pci_read_config_word(pdev, pos + PCI_EXP_DEVCAP, &reg16);

	pdev->pcie_mpss = reg16 & PCI_EXP_DEVCAP_PAYLOAD;

	pci_read_config_dword(pdev, pos + PCI_EXP_DEVCAP, &pdev->devcap);

	pdev->pcie_mpss = FIELD_GET(PCI_EXP_DEVCAP_PAYLOAD, pdev->devcap);



	parent = pci_upstream_bridge(pdev);

	if (!parent)

include/linux/pci.h

+1 −0
Original line number Diff line number Diff line
@@ -333,6 +333,7 @@ struct pci_dev { 
	struct rcec_ea	*rcec_ea;	/* RCEC cached endpoint association */

	struct pci_dev  *rcec;          /* Associated RCEC device */

#endif

	u32		devcap;		/* PCIe Device Capabilities */

	u8		pcie_cap;	/* PCIe capability offset */

	u8		msi_cap;	/* MSI capability offset */

	u8		msix_cap;	/* MSI-X capability offset */