dca: disable dca on IOAT ver.3.0 multiple-IOH platforms

Direct Cache Access is not supported on IOAT ver.3.0 multiple-IOH platforms.
This patch blocks registering of dca providers when multiple IOH detected with IOAT ver.3.0.

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 79 insertions, 6 deletions

diff --git a/drivers/dca/dca-core.c b/drivers/dca/dca-core.c
index 8661c84a105d..b98c67664ae7 100644
--- a/drivers/dca/dca-core.c
+++ b/drivers/dca/dca-core.c
@@ -39,6 +39,10 @@ static DEFINE_SPINLOCK(dca_lock);
 
 static LIST_HEAD(dca_domains);
 
+static BLOCKING_NOTIFIER_HEAD(dca_provider_chain);
+
+static int dca_providers_blocked;
+
 static struct pci_bus *dca_pci_rc_from_dev(struct device *dev)
 {
         struct pci_dev *pdev = to_pci_dev(dev);
@@ -70,6 +74,60 @@ static void dca_free_domain(struct dca_domain *domain)
         kfree(domain);
 }
 
+static int dca_provider_ioat_ver_3_0(struct device *dev)
+{
+        struct pci_dev *pdev = to_pci_dev(dev);
+
+        return ((pdev->vendor == PCI_VENDOR_ID_INTEL) &&
+                ((pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG0) ||
+                (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG1) ||
+                (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG2) ||
+                (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG3) ||
+                (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG4) ||
+                (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG5) ||
+                (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG6) ||
+                (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG7)));
+}
+
+static void unregister_dca_providers(void)
+{
+        struct dca_provider *dca, *_dca;
+        struct list_head unregistered_providers;
+        struct dca_domain *domain;
+        unsigned long flags;
+
+        blocking_notifier_call_chain(&dca_provider_chain,
+                                     DCA_PROVIDER_REMOVE, NULL);
+
+        INIT_LIST_HEAD(&unregistered_providers);
+
+        spin_lock_irqsave(&dca_lock, flags);
+
+        if (list_empty(&dca_domains)) {
+                spin_unlock_irqrestore(&dca_lock, flags);
+                return;
+        }
+
+        /* at this point only one domain in the list is expected */
+        domain = list_first_entry(&dca_domains, struct dca_domain, node);
+        if (!domain)
+                return;
+
+        list_for_each_entry_safe(dca, _dca, &domain->dca_providers, node) {
+                list_del(&dca->node);
+                list_add(&dca->node, &unregistered_providers);
+        }
+
+        dca_free_domain(domain);
+
+        spin_unlock_irqrestore(&dca_lock, flags);
+
+        list_for_each_entry_safe(dca, _dca, &unregistered_providers, node) {
+                dca_sysfs_remove_provider(dca);
+                list_del(&dca->node);
+        }
+}
+
 static struct dca_domain *dca_find_domain(struct pci_bus *rc)
 {
         struct dca_domain *domain;
@@ -90,9 +148,13 @@ static struct dca_domain *dca_get_domain(struct device *dev)
         domain = dca_find_domain(rc);
 
         if (!domain) {
-                domain = dca_allocate_domain(rc);
-                if (domain)
-                        list_add(&domain->node, &dca_domains);
+                if (dca_provider_ioat_ver_3_0(dev) && !list_empty(&dca_domains)) {
+                        dca_providers_blocked = 1;
+                } else {
+                        domain = dca_allocate_domain(rc);
+                        if (domain)
+                                list_add(&domain->node, &dca_domains);
+                }
         }
 
         return domain;
@@ -293,8 +355,6 @@ void free_dca_provider(struct dca_provider *dca)
 }
 EXPORT_SYMBOL_GPL(free_dca_provider);
 
-static BLOCKING_NOTIFIER_HEAD(dca_provider_chain);
-
 /**
  * register_dca_provider - register a dca provider
  * @dca - struct created by alloc_dca_provider()
@@ -306,6 +366,13 @@ int register_dca_provider(struct dca_provider *dca, struct device *dev)
         unsigned long flags;
         struct dca_domain *domain;
 
+        spin_lock_irqsave(&dca_lock, flags);
+        if (dca_providers_blocked) {
+                spin_unlock_irqrestore(&dca_lock, flags);
+                return -ENODEV;
+        }
+        spin_unlock_irqrestore(&dca_lock, flags);
+
         err = dca_sysfs_add_provider(dca, dev);
         if (err)
                 return err;
@@ -313,7 +380,13 @@ int register_dca_provider(struct dca_provider *dca, struct device *dev)
         spin_lock_irqsave(&dca_lock, flags);
         domain = dca_get_domain(dev);
         if (!domain) {
-                spin_unlock_irqrestore(&dca_lock, flags);
+                if (dca_providers_blocked) {
+                        spin_unlock_irqrestore(&dca_lock, flags);
+                        dca_sysfs_remove_provider(dca);
+                        unregister_dca_providers();
+                } else {
+                        spin_unlock_irqrestore(&dca_lock, flags);
+                }
                 return -ENODEV;
         }
         list_add(&dca->node, &domain->dca_providers);