I/OAT: I/OAT version 3.0 support

This patch adds to ioatdma and dca modules
support for Intel I/OAT DMA engine ver.3 (aka CB3 device).
The main features of I/OAT ver.3 are:
 * 8 single channel DMA devices (8 channels total)
 * 8 DCA providers, each can accept 2 requesters
 * 8-bit TAG values and 32-bit extended APIC IDs

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

2 files changed, 105 insertions, 29 deletions

diff --git a/drivers/dca/dca-core.c b/drivers/dca/dca-core.c
index bf5b92f86df7..ec249d2db633 100644
--- a/drivers/dca/dca-core.c
+++ b/drivers/dca/dca-core.c
@@ -28,13 +28,29 @@
 #include <linux/device.h>
 #include <linux/dca.h>
 
-MODULE_LICENSE("GPL");
+#define DCA_VERSION "1.4"
 
-/* For now we're assuming a single, global, DCA provider for the system. */
+MODULE_VERSION(DCA_VERSION);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Intel Corporation");
 
 static DEFINE_SPINLOCK(dca_lock);
 
-static struct dca_provider *global_dca = NULL;
+static LIST_HEAD(dca_providers);
+
+static struct dca_provider *dca_find_provider_by_dev(struct device *dev)
+{
+        struct dca_provider *dca, *ret = NULL;
+
+        list_for_each_entry(dca, &dca_providers, node) {
+                if ((!dev) || (dca->ops->dev_managed(dca, dev))) {
+                        ret = dca;
+                        break;
+                }
+        }
+
+        return ret;
+}
 
 /**
  * dca_add_requester - add a dca client to the list
@@ -42,25 +58,39 @@ static struct dca_provider *global_dca = NULL;
  */
 int dca_add_requester(struct device *dev)
 {
-        int err, slot;
+        struct dca_provider *dca;
+        int err, slot = -ENODEV;
 
-        if (!global_dca)
-                return -ENODEV;
+        if (!dev)
+                return -EFAULT;
 
         spin_lock(&dca_lock);
-        slot = global_dca->ops->add_requester(global_dca, dev);
-        spin_unlock(&dca_lock);
-        if (slot < 0)
+
+        /* check if the requester has not been added already */
+        dca = dca_find_provider_by_dev(dev);
+        if (dca) {
+                spin_unlock(&dca_lock);
+                return -EEXIST;
+        }
+
+        list_for_each_entry(dca, &dca_providers, node) {
+                slot = dca->ops->add_requester(dca, dev);
+                if (slot >= 0)
+                        break;
+        }
+        if (slot < 0) {
+                spin_unlock(&dca_lock);
                 return slot;
+        }
 
-        err = dca_sysfs_add_req(global_dca, dev, slot);
+        err = dca_sysfs_add_req(dca, dev, slot);
         if (err) {
-                spin_lock(&dca_lock);
-                global_dca->ops->remove_requester(global_dca, dev);
+                dca->ops->remove_requester(dca, dev);
                 spin_unlock(&dca_lock);
                 return err;
         }
 
+        spin_unlock(&dca_lock);
         return 0;
 }
 EXPORT_SYMBOL_GPL(dca_add_requester);
@@ -71,30 +101,78 @@ EXPORT_SYMBOL_GPL(dca_add_requester);
  */
 int dca_remove_requester(struct device *dev)
 {
+        struct dca_provider *dca;
         int slot;
-        if (!global_dca)
-                return -ENODEV;
+
+        if (!dev)
+                return -EFAULT;
 
         spin_lock(&dca_lock);
-        slot = global_dca->ops->remove_requester(global_dca, dev);
-        spin_unlock(&dca_lock);
-        if (slot < 0)
+        dca = dca_find_provider_by_dev(dev);
+        if (!dca) {
+                spin_unlock(&dca_lock);
+                return -ENODEV;
+        }
+        slot = dca->ops->remove_requester(dca, dev);
+        if (slot < 0) {
+                spin_unlock(&dca_lock);
                 return slot;
+        }
 
-        dca_sysfs_remove_req(global_dca, slot);
+        dca_sysfs_remove_req(dca, slot);
+
+        spin_unlock(&dca_lock);
         return 0;
 }
 EXPORT_SYMBOL_GPL(dca_remove_requester);
 
 /**
- * dca_get_tag - return the dca tag for the given cpu
+ * dca_common_get_tag - return the dca tag (serves both new and old api)
+ * @dev - the device that wants dca service
  * @cpu - the cpuid as returned by get_cpu()
  */
-u8 dca_get_tag(int cpu)
+u8 dca_common_get_tag(struct device *dev, int cpu)
 {
-        if (!global_dca)
+        struct dca_provider *dca;
+        u8 tag;
+
+        spin_lock(&dca_lock);
+
+        dca = dca_find_provider_by_dev(dev);
+        if (!dca) {
+                spin_unlock(&dca_lock);
                 return -ENODEV;
-        return global_dca->ops->get_tag(global_dca, cpu);
+        }
+        tag = dca->ops->get_tag(dca, dev, cpu);
+
+        spin_unlock(&dca_lock);
+        return tag;
+}
+
+/**
+ * dca3_get_tag - return the dca tag to the requester device
+ *                for the given cpu (new api)
+ * @dev - the device that wants dca service
+ * @cpu - the cpuid as returned by get_cpu()
+ */
+u8 dca3_get_tag(struct device *dev, int cpu)
+{
+        if (!dev)
+                return -EFAULT;
+
+        return dca_common_get_tag(dev, cpu);
+}
+EXPORT_SYMBOL_GPL(dca3_get_tag);
+
+/**
+ * dca_get_tag - return the dca tag for the given cpu (old api)
+ * @cpu - the cpuid as returned by get_cpu()
+ */
+u8 dca_get_tag(int cpu)
+{
+        struct device *dev = NULL;
+
+        return dca_common_get_tag(dev, cpu);
 }
 EXPORT_SYMBOL_GPL(dca_get_tag);
 
@@ -140,12 +218,10 @@ int register_dca_provider(struct dca_provider *dca, struct device *dev)
 {
         int err;
 
-        if (global_dca)
-                return -EEXIST;
         err = dca_sysfs_add_provider(dca, dev);
         if (err)
                 return err;
-        global_dca = dca;
+        list_add(&dca->node, &dca_providers);
         blocking_notifier_call_chain(&dca_provider_chain,
                                      DCA_PROVIDER_ADD, NULL);
         return 0;
@@ -158,11 +234,9 @@ EXPORT_SYMBOL_GPL(register_dca_provider);
  */
 void unregister_dca_provider(struct dca_provider *dca)
 {
-        if (!global_dca)
-                return;
         blocking_notifier_call_chain(&dca_provider_chain,
                                      DCA_PROVIDER_REMOVE, NULL);
-        global_dca = NULL;
+        list_del(&dca->node);
         dca_sysfs_remove_provider(dca);
 }
 EXPORT_SYMBOL_GPL(unregister_dca_provider);
@@ -187,6 +261,7 @@ EXPORT_SYMBOL_GPL(dca_unregister_notify);
 
 static int __init dca_init(void)
 {
+        printk(KERN_ERR "dca service started, version %s\n", DCA_VERSION);
         return dca_sysfs_init();
 }
 
diff --git a/drivers/dca/dca-sysfs.c b/drivers/dca/dca-sysfs.c
index 011328faa5f2..3d47e9d8e34f 100644
--- a/drivers/dca/dca-sysfs.c
+++ b/drivers/dca/dca-sysfs.c
@@ -13,9 +13,10 @@ static spinlock_t dca_idr_lock;
 int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot)
 {
         struct device *cd;
+        static int req_count;
 
         cd = device_create(dca_class, dca->cd, MKDEV(0, slot + 1),
-                           "requester%d", slot);
+                           "requester%d", req_count++);
         if (IS_ERR(cd))
                 return PTR_ERR(cd);
         return 0;