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Subject[PATCH v4 2/7] PCI/ATS: Initialize PRI in pci_ats_init()
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. Also, since PRI is a shared resource between PF/VF,
initialize default values for common PRI features in pci_pri_init().

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
drivers/pci/ats.c | 83 +++++++++++++++++++++++++++++++--------------
include/linux/pci.h | 1 +
2 files changed, 59 insertions(+), 25 deletions(-)

diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index f9eeb7db0db3..a14ab20f1c28 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -16,6 +16,40 @@

#include "pci.h"

+#ifdef CONFIG_PCI_PRI
+static void pci_pri_init(struct pci_dev *pdev)
+{
+ u32 max_requests;
+ int pos;
+
+ /*
+ * As per PCIe r4.0, sec 9.3.7.11, only PF is permitted to
+ * implement PRI and all associated VFs can only use it.
+ * Since PF already initialized the PRI parameters there is
+ * no need to proceed further.
+ */
+ if (pdev->is_virtfn)
+ return;
+
+ pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
+ if (!pos)
+ return;
+
+ pci_read_config_dword(pdev, pos + PCI_PRI_MAX_REQ, &max_requests);
+
+ /*
+ * Since PRI is a shared resource between PF and VF, we must not
+ * configure Outstanding Page Allocation Quota as a per device
+ * resource in pci_enable_pri(). So use maximum value possible
+ * as default value.
+ */
+ pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, max_requests);
+
+ pdev->pri_reqs_alloc = max_requests;
+ pdev->pri_cap = pos;
+}
+#endif
+
void pci_ats_init(struct pci_dev *dev)
{
int pos;
@@ -28,6 +62,10 @@ void pci_ats_init(struct pci_dev *dev)
return;

dev->ats_cap = pos;
+
+#ifdef CONFIG_PCI_PRI
+ pci_pri_init(dev);
+#endif
}

/**
@@ -175,31 +213,34 @@ EXPORT_SYMBOL_GPL(pci_ats_page_aligned);
* @ pdev: PCI device structure
*
* Returns 0 on success, negative value on error
+ *
+ * TODO: Since PRI is a shared resource between PF/VF, don't update
+ * Outstanding Page Allocation Quota in the same API as a per device
+ * feature.
*/
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 +257,16 @@ 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 +280,15 @@ 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 +302,15 @@ 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 +445,11 @@ 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 dd436da7eccc..f3fe625bc8bb 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -452,6 +452,7 @@ 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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