From: CQ Tang <cq.t...@intel.com>

Requires: https://patchwork.kernel.org/patch/9593891

After a FLR, pci-states need to be restored. This patch saves PASID features
and PRI reqs cached.

Cc: Jean-Phillipe Brucker <jean-philippe.bruc...@arm.com>
Cc: David Woodhouse <dw...@infradead.org>
Cc: iommu@lists.linux-foundation.org

Signed-off-by: CQ Tang <cq.t...@intel.com>
Signed-off-by: Ashok Raj <ashok....@intel.com>
---
 drivers/pci/ats.c       | 65 +++++++++++++++++++++++++++++++++++++------------
 drivers/pci/pci.c       |  3 +++
 include/linux/pci-ats.h | 10 ++++++++
 include/linux/pci.h     |  6 +++++
 4 files changed, 69 insertions(+), 15 deletions(-)

diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index 2126497..a769955 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -160,17 +160,16 @@ int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
        if (!pos)
                return -EINVAL;
 
-       pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
        pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
-       if ((control & PCI_PRI_CTRL_ENABLE) ||
-           !(status & PCI_PRI_STATUS_STOPPED))
+       if (!(status & PCI_PRI_STATUS_STOPPED))
                return -EBUSY;
 
        pci_read_config_dword(pdev, pos + 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);
 
-       control |= PCI_PRI_CTRL_ENABLE;
+       control = PCI_PRI_CTRL_ENABLE;
        pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
 
        pdev->pri_enabled = 1;
@@ -206,6 +205,29 @@ void pci_disable_pri(struct pci_dev *pdev)
 EXPORT_SYMBOL_GPL(pci_disable_pri);
 
 /**
+ * pci_restore_pri_state - Restore PRI
+ * @pdev: PCI device structure
+ *
+ */
+void pci_restore_pri_state(struct pci_dev *pdev)
+{
+   u16 control = PCI_PRI_CTRL_ENABLE;
+   u32 reqs = pdev->pri_reqs_alloc;
+   int pos;
+
+   pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
+   if (!pos)
+       return;
+
+   if (!pdev->pri_enabled)
+       return;
+
+   pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);
+   pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
+}
+EXPORT_SYMBOL_GPL(pci_restore_pri_state);
+
+/**
  * pci_reset_pri - Resets device's PRI state
  * @pdev: PCI device structure
  *
@@ -224,12 +246,7 @@ int pci_reset_pri(struct pci_dev *pdev)
        if (!pos)
                return -EINVAL;
 
-       pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
-       if (control & PCI_PRI_CTRL_ENABLE)
-               return -EBUSY;
-
-       control |= PCI_PRI_CTRL_RESET;
-
+       control = PCI_PRI_CTRL_RESET;
        pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
 
        return 0;
@@ -259,12 +276,7 @@ int pci_enable_pasid(struct pci_dev *pdev, int features)
        if (!pos)
                return -EINVAL;
 
-       pci_read_config_word(pdev, pos + PCI_PASID_CTRL, &control);
        pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
-
-       if (control & PCI_PASID_CTRL_ENABLE)
-               return -EINVAL;
-
        supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;
 
        /* User wants to enable anything unsupported? */
@@ -272,6 +284,7 @@ int pci_enable_pasid(struct pci_dev *pdev, int features)
                return -EINVAL;
 
        control = PCI_PASID_CTRL_ENABLE | features;
+       pdev->pasid_features = features;
 
        pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
 
@@ -305,6 +318,28 @@ void pci_disable_pasid(struct pci_dev *pdev)
 EXPORT_SYMBOL_GPL(pci_disable_pasid);
 
 /**
+ * pci_restore_pasid_state - Restore PASID capabilities.
+ * @pdev: PCI device structure
+ *
+ */
+void pci_restore_pasid_state(struct pci_dev *pdev)
+{
+   u16 control;
+   int pos;
+
+   pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
+   if (!pos)
+       return;
+
+   if (!pdev->pasid_enabled)
+       return;
+
+   control = PCI_PASID_CTRL_ENABLE | pdev->pasid_features;
+   pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
+}
+EXPORT_SYMBOL_GPL(pci_restore_pasid_state);
+
+/**
  * pci_pasid_features - Check which PASID features are supported
  * @pdev: PCI device structure
  *
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 7904d02..c9a6510 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -28,6 +28,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/pci_hotplug.h>
 #include <linux/vmalloc.h>
+#include <linux/pci-ats.h>
 #include <asm/setup.h>
 #include <asm/dma.h>
 #include <linux/aer.h>
@@ -1171,6 +1172,8 @@ void pci_restore_state(struct pci_dev *dev)
 
        /* PCI Express register must be restored first */
        pci_restore_pcie_state(dev);
+       pci_restore_pasid_state(dev);
+       pci_restore_pri_state(dev);
        pci_restore_ats_state(dev);
        pci_restore_vc_state(dev);
 
diff --git a/include/linux/pci-ats.h b/include/linux/pci-ats.h
index 57e0b82..782fb8e 100644
--- a/include/linux/pci-ats.h
+++ b/include/linux/pci-ats.h
@@ -7,6 +7,7 @@
 
 int pci_enable_pri(struct pci_dev *pdev, u32 reqs);
 void pci_disable_pri(struct pci_dev *pdev);
+void pci_restore_pri_state(struct pci_dev *pdev);
 int pci_reset_pri(struct pci_dev *pdev);
 
 #else /* CONFIG_PCI_PRI */
@@ -20,6 +21,10 @@ static inline void pci_disable_pri(struct pci_dev *pdev)
 {
 }
 
+static inline void pci_restore_pri_state(struct pci_dev *pdev)
+{
+}
+
 static inline int pci_reset_pri(struct pci_dev *pdev)
 {
        return -ENODEV;
@@ -31,6 +36,7 @@ static inline int pci_reset_pri(struct pci_dev *pdev)
 
 int pci_enable_pasid(struct pci_dev *pdev, int features);
 void pci_disable_pasid(struct pci_dev *pdev);
+void pci_restore_pasid_state(struct pci_dev *pdev);
 int pci_pasid_features(struct pci_dev *pdev);
 int pci_max_pasids(struct pci_dev *pdev);
 
@@ -45,6 +51,10 @@ static inline void pci_disable_pasid(struct pci_dev *pdev)
 {
 }
 
+static inline void pci_restore_pasid_state(struct pci_dev *pdev)
+{
+}
+
 static inline int pci_pasid_features(struct pci_dev *pdev)
 {
        return -EINVAL;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index bee980e..1ddb8e0 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -395,6 +395,12 @@ struct pci_dev {
        u8              ats_stu;        /* ATS Smallest Translation Unit */
        atomic_t        ats_ref_cnt;    /* number of VFs with ATS enabled */
 #endif
+#ifdef CONFIG_PCI_PRI
+       u32             pri_reqs_alloc; /* Number of PRI requests allocated */
+#endif
+#ifdef CONFIG_PCI_PASID
+       u16             pasid_features;
+#endif
        phys_addr_t rom; /* Physical address of ROM if it's not from the BAR */
        size_t romlen; /* Length of ROM if it's not from the BAR */
        char *driver_override; /* Driver name to force a match */
-- 
2.7.4

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