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PCI/ATS: Cache PRI Capability offset
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Previously each PRI interface searched for the PRI Capability.  Cache the
capability offset the first time we use it instead of searching each time.

[bhelgaas: commit log, reorder patch to later, call pci_pri_init() from
pci_init_capabilities()]
Link: https://lore.kernel.org/r/0c5495d376faf6dbb8eb2165204c474438aaae65.156
7029860.git.sathyanarayanan.kuppuswamy@linux.intel.com
Link: https://lore.kernel.org/r/20190905193146.90250-5-helgaas@kernel.org
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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Kuppuswamy Sathyanarayanan authored and Bjorn Helgaas committed Oct 15, 2019
1 parent 3ad6219 commit c065190
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Showing 4 changed files with 36 additions and 25 deletions.
51 changes: 26 additions & 25 deletions drivers/pci/ats.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -159,6 +159,11 @@ int pci_ats_page_aligned(struct pci_dev *pdev)
EXPORT_SYMBOL_GPL(pci_ats_page_aligned);

#ifdef CONFIG_PCI_PRI
void pci_pri_init(struct pci_dev *pdev)
{
pdev->pri_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
}

/**
* pci_enable_pri - Enable PRI capability
* @ pdev: PCI device structure
Expand All @@ -169,7 +174,7 @@ int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
{
u16 control, status;
u32 max_requests;
int pos;
int pri = pdev->pri_cap;

/*
* VFs must not implement the PRI Capability. If their PF
Expand All @@ -185,21 +190,20 @@ int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
if (WARN_ON(pdev->pri_enabled))
return -EBUSY;

pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
if (!pos)
if (!pri)
return -EINVAL;

pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
pci_read_config_word(pdev, pri + PCI_PRI_STATUS, &status);
if (!(status & PCI_PRI_STATUS_STOPPED))
return -EBUSY;

pci_read_config_dword(pdev, pos + PCI_PRI_MAX_REQ, &max_requests);
pci_read_config_dword(pdev, pri + PCI_PRI_MAX_REQ, &max_requests);
reqs = min(max_requests, reqs);
pdev->pri_reqs_alloc = reqs;
pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);
pci_write_config_dword(pdev, pri + PCI_PRI_ALLOC_REQ, reqs);

control = PCI_PRI_CTRL_ENABLE;
pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
pci_write_config_word(pdev, pri + PCI_PRI_CTRL, control);

pdev->pri_enabled = 1;

Expand All @@ -216,7 +220,7 @@ EXPORT_SYMBOL_GPL(pci_enable_pri);
void pci_disable_pri(struct pci_dev *pdev)
{
u16 control;
int pos;
int pri = pdev->pri_cap;

/* VFs share the PF PRI */
if (pdev->is_virtfn)
Expand All @@ -225,13 +229,12 @@ void pci_disable_pri(struct pci_dev *pdev)
if (WARN_ON(!pdev->pri_enabled))
return;

pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
if (!pos)
if (!pri)
return;

pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
pci_read_config_word(pdev, pri + PCI_PRI_CTRL, &control);
control &= ~PCI_PRI_CTRL_ENABLE;
pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
pci_write_config_word(pdev, pri + PCI_PRI_CTRL, control);

pdev->pri_enabled = 0;
}
Expand All @@ -245,20 +248,19 @@ void pci_restore_pri_state(struct pci_dev *pdev)
{
u16 control = PCI_PRI_CTRL_ENABLE;
u32 reqs = pdev->pri_reqs_alloc;
int pos;
int pri = pdev->pri_cap;

if (pdev->is_virtfn)
return;

if (!pdev->pri_enabled)
return;

pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
if (!pos)
if (!pri)
return;

pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);
pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
pci_write_config_dword(pdev, pri + PCI_PRI_ALLOC_REQ, reqs);
pci_write_config_word(pdev, pri + PCI_PRI_CTRL, control);
}
EXPORT_SYMBOL_GPL(pci_restore_pri_state);

Expand All @@ -272,20 +274,19 @@ EXPORT_SYMBOL_GPL(pci_restore_pri_state);
int pci_reset_pri(struct pci_dev *pdev)
{
u16 control;
int pos;
int pri = pdev->pri_cap;

if (pdev->is_virtfn)
return 0;

if (WARN_ON(pdev->pri_enabled))
return -EBUSY;

pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
if (!pos)
if (!pri)
return -EINVAL;

control = PCI_PRI_CTRL_RESET;
pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
pci_write_config_word(pdev, pri + PCI_PRI_CTRL, control);

return 0;
}
Expand All @@ -301,16 +302,16 @@ EXPORT_SYMBOL_GPL(pci_reset_pri);
int pci_prg_resp_pasid_required(struct pci_dev *pdev)
{
u16 status;
int pos;
int pri;

if (pdev->is_virtfn)
pdev = pci_physfn(pdev);

pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
if (!pos)
pri = pdev->pri_cap;
if (!pri)
return 0;

pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
pci_read_config_word(pdev, pri + PCI_PRI_STATUS, &status);

if (status & PCI_PRI_STATUS_PASID)
return 1;
Expand Down
6 changes: 6 additions & 0 deletions drivers/pci/pci.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -456,6 +456,12 @@ static inline void pci_ats_init(struct pci_dev *d) { }
static inline void pci_restore_ats_state(struct pci_dev *dev) { }
#endif /* CONFIG_PCI_ATS */

#ifdef CONFIG_PCI_PRI
void pci_pri_init(struct pci_dev *dev);
#else
static inline void pci_pri_init(struct pci_dev *dev) { }
#endif

#ifdef CONFIG_PCI_IOV
int pci_iov_init(struct pci_dev *dev);
void pci_iov_release(struct pci_dev *dev);
Expand Down
3 changes: 3 additions & 0 deletions drivers/pci/probe.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2324,6 +2324,9 @@ static void pci_init_capabilities(struct pci_dev *dev)
/* Address Translation Services */
pci_ats_init(dev);

/* Page Request Interface */
pci_pri_init(dev);

/* Enable ACS P2P upstream forwarding */
pci_enable_acs(dev);

Expand Down
1 change: 1 addition & 0 deletions include/linux/pci.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -454,6 +454,7 @@ struct pci_dev {
u8 ats_stu; /* ATS Smallest Translation Unit */
#endif
#ifdef CONFIG_PCI_PRI
u16 pri_cap; /* PRI Capability offset */
u32 pri_reqs_alloc; /* Number of PRI requests allocated */
#endif
#ifdef CONFIG_PCI_PASID
Expand Down

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