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Subject[PATCH v7 2/7] PCI/ATS: Cache PRI capability check result
Date
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

Currently, PRI capability checks are repeated across all PRI API's.
Instead, cache the capability check result in pci_pri_init() and use it
in other PRI API's.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
drivers/pci/ats.c | 56 +++++++++++++++++++++++++--------------------
include/linux/pci.h | 1 +
2 files changed, 32 insertions(+), 25 deletions(-)

diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index cdd936d10f68..b863562b6702 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -16,6 +16,19 @@

#include "pci.h"

+static void pci_pri_init(struct pci_dev *pdev)
+{
+#ifdef CONFIG_PCI_PRI
+ int pos;
+
+ pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
+ if (!pos)
+ return;
+
+ pdev->pri_cap = pos;
+#endif
+}
+
void pci_ats_init(struct pci_dev *dev)
{
int pos;
@@ -28,6 +41,8 @@ void pci_ats_init(struct pci_dev *dev)
return;

dev->ats_cap = pos;
+
+ pci_pri_init(dev);
}

/**
@@ -180,26 +195,25 @@ int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
{
u16 control, status;
u32 max_requests;
- int pos;

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

- pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
- if (!pos)
+ if (!pdev->pri_cap)
return -EINVAL;

- pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
+ pci_read_config_word(pdev, pdev->pri_cap + 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, pdev->pri_cap + 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, pdev->pri_cap + 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, pdev->pri_cap + PCI_PRI_CTRL, control);

pdev->pri_enabled = 1;

@@ -216,18 +230,16 @@ EXPORT_SYMBOL_GPL(pci_enable_pri);
void pci_disable_pri(struct pci_dev *pdev)
{
u16 control;
- int pos;

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

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

- pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
+ pci_read_config_word(pdev, pdev->pri_cap + PCI_PRI_CTRL, &control);
control &= ~PCI_PRI_CTRL_ENABLE;
- pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
+ pci_write_config_word(pdev, pdev->pri_cap + PCI_PRI_CTRL, control);

pdev->pri_enabled = 0;
}
@@ -241,17 +253,15 @@ void pci_restore_pri_state(struct pci_dev *pdev)
{
u16 control = PCI_PRI_CTRL_ENABLE;
u32 reqs = pdev->pri_reqs_alloc;
- int pos;

if (!pdev->pri_enabled)
return;

- pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
- if (!pos)
+ if (!pdev->pri_cap)
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, pdev->pri_cap + PCI_PRI_ALLOC_REQ, reqs);
+ pci_write_config_word(pdev, pdev->pri_cap + PCI_PRI_CTRL, control);
}
EXPORT_SYMBOL_GPL(pci_restore_pri_state);

@@ -265,17 +275,15 @@ EXPORT_SYMBOL_GPL(pci_restore_pri_state);
int pci_reset_pri(struct pci_dev *pdev)
{
u16 control;
- int pos;

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

- pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
- if (!pos)
+ if (!pdev->pri_cap)
return -EINVAL;

control = PCI_PRI_CTRL_RESET;
- pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
+ pci_write_config_word(pdev, pdev->pri_cap + PCI_PRI_CTRL, control);

return 0;
}
@@ -410,13 +418,11 @@ EXPORT_SYMBOL_GPL(pci_pasid_features);
int pci_prg_resp_pasid_required(struct pci_dev *pdev)
{
u16 status;
- int pos;

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

- pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
+ pci_read_config_word(pdev, pdev->pri_cap + PCI_PRI_STATUS, &status);

if (status & PCI_PRI_STATUS_PASID)
return 1;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 82e4cd1b7ac3..79991984c4cd 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -455,6 +455,7 @@ struct pci_dev {
atomic_t ats_ref_cnt; /* Number of VFs with ATS enabled */
#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
--
2.21.0
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