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>

8 files changed, 467 insertions, 48 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;
diff --git a/drivers/dma/ioat.c b/drivers/dma/ioat.c
index 16e0fd8facfb..9b16a3af9a0a 100644
--- a/drivers/dma/ioat.c
+++ b/drivers/dma/ioat.c
@@ -47,6 +47,16 @@ static struct pci_device_id ioat_pci_tbl[] = {
 
         /* I/OAT v2 platforms */
         { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_SNB) },
+
+        /* I/OAT v3 platforms */
+        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_TBG0) },
+        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_TBG1) },
+        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_TBG2) },
+        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_TBG3) },
+        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_TBG4) },
+        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_TBG5) },
+        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_TBG6) },
+        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_TBG7) },
         { 0, }
 };
 
@@ -83,6 +93,11 @@ static int ioat_setup_functionality(struct pci_dev *pdev, void __iomem *iobase)
                 if (device->dma && ioat_dca_enabled)
                         device->dca = ioat2_dca_init(pdev, iobase);
                 break;
+        case IOAT_VER_3_0:
+                device->dma = ioat_dma_probe(pdev, iobase);
+                if (device->dma && ioat_dca_enabled)
+                        device->dca = ioat3_dca_init(pdev, iobase);
+                break;
         default:
                 err = -ENODEV;
                 break;
diff --git a/drivers/dma/ioat_dca.c b/drivers/dma/ioat_dca.c
index 9e922760b7ff..6cf622da0286 100644
--- a/drivers/dma/ioat_dca.c
+++ b/drivers/dma/ioat_dca.c
@@ -37,12 +37,18 @@
 #include "ioatdma_registers.h"
 
 /*
- * Bit 16 of a tag map entry is the "valid" bit, if it is set then bits 0:15
+ * Bit 7 of a tag map entry is the "valid" bit, if it is set then bits 0:6
  * contain the bit number of the APIC ID to map into the DCA tag.  If the valid
  * bit is not set, then the value must be 0 or 1 and defines the bit in the tag.
  */
 #define DCA_TAG_MAP_VALID 0x80
 
+#define DCA3_TAG_MAP_BIT_TO_INV 0x80
+#define DCA3_TAG_MAP_BIT_TO_SEL 0x40
+#define DCA3_TAG_MAP_LITERAL_VAL 0x1
+
+#define DCA_TAG_MAP_MASK 0xDF
+
 /*
  * "Legacy" DCA systems do not implement the DCA register set in the
  * I/OAT device.  Software needs direct support for their tag mappings.
@@ -95,6 +101,7 @@ struct ioat_dca_slot {
 };
 
 #define IOAT_DCA_MAX_REQ 6
+#define IOAT3_DCA_MAX_REQ 2
 
 struct ioat_dca_priv {
         void __iomem            *iobase;
@@ -171,7 +178,9 @@ static int ioat_dca_remove_requester(struct dca_provider *dca,
         return -ENODEV;
 }
 
-static u8 ioat_dca_get_tag(struct dca_provider *dca, int cpu)
+static u8 ioat_dca_get_tag(struct dca_provider *dca,
+                           struct device *dev,
+                           int cpu)
 {
         struct ioat_dca_priv *ioatdca = dca_priv(dca);
         int i, apic_id, bit, value;
@@ -193,10 +202,26 @@ static u8 ioat_dca_get_tag(struct dca_provider *dca, int cpu)
         return tag;
 }
 
+static int ioat_dca_dev_managed(struct dca_provider *dca,
+                                struct device *dev)
+{
+        struct ioat_dca_priv *ioatdca = dca_priv(dca);
+        struct pci_dev *pdev;
+        int i;
+
+        pdev = to_pci_dev(dev);
+        for (i = 0; i < ioatdca->max_requesters; i++) {
+                if (ioatdca->req_slots[i].pdev == pdev)
+                        return 1;
+        }
+        return 0;
+}
+
 static struct dca_ops ioat_dca_ops = {
         .add_requester          = ioat_dca_add_requester,
         .remove_requester       = ioat_dca_remove_requester,
         .get_tag                = ioat_dca_get_tag,
+        .dev_managed            = ioat_dca_dev_managed,
 };
 
 
@@ -207,6 +232,8 @@ struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase)
         u8 *tag_map = NULL;
         int i;
         int err;
+        u8 version;
+        u8 max_requesters;
 
         if (!system_has_dca_enabled(pdev))
                 return NULL;
@@ -237,15 +264,20 @@ struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase)
         if (tag_map == NULL)
                 return NULL;
 
+        version = readb(iobase + IOAT_VER_OFFSET);
+        if (version == IOAT_VER_3_0)
+                max_requesters = IOAT3_DCA_MAX_REQ;
+        else
+                max_requesters = IOAT_DCA_MAX_REQ;
+
         dca = alloc_dca_provider(&ioat_dca_ops,
                         sizeof(*ioatdca) +
-                        (sizeof(struct ioat_dca_slot) * IOAT_DCA_MAX_REQ));
+                        (sizeof(struct ioat_dca_slot) * max_requesters));
         if (!dca)
                 return NULL;
 
         ioatdca = dca_priv(dca);
-        ioatdca->max_requesters = IOAT_DCA_MAX_REQ;
-
+        ioatdca->max_requesters = max_requesters;
         ioatdca->dca_base = iobase + 0x54;
 
         /* copy over the APIC ID to DCA tag mapping */
@@ -323,11 +355,13 @@ static int ioat2_dca_remove_requester(struct dca_provider *dca,
         return -ENODEV;
 }
 
-static u8 ioat2_dca_get_tag(struct dca_provider *dca, int cpu)
+static u8 ioat2_dca_get_tag(struct dca_provider *dca,
+                            struct device *dev,
+                            int cpu)
 {
         u8 tag;
 
-        tag = ioat_dca_get_tag(dca, cpu);
+        tag = ioat_dca_get_tag(dca, dev, cpu);
         tag = (~tag) & 0x1F;
         return tag;
 }
@@ -336,6 +370,7 @@ static struct dca_ops ioat2_dca_ops = {
         .add_requester          = ioat2_dca_add_requester,
         .remove_requester       = ioat2_dca_remove_requester,
         .get_tag                = ioat2_dca_get_tag,
+        .dev_managed            = ioat_dca_dev_managed,
 };
 
 static int ioat2_dca_count_dca_slots(void __iomem *iobase, u16 dca_offset)
@@ -425,3 +460,198 @@ struct dca_provider *ioat2_dca_init(struct pci_dev *pdev, void __iomem *iobase)
 
         return dca;
 }
+
+static int ioat3_dca_add_requester(struct dca_provider *dca, struct device *dev)
+{
+        struct ioat_dca_priv *ioatdca = dca_priv(dca);
+        struct pci_dev *pdev;
+        int i;
+        u16 id;
+        u16 global_req_table;
+
+        /* This implementation only supports PCI-Express */
+        if (dev->bus != &pci_bus_type)
+                return -ENODEV;
+        pdev = to_pci_dev(dev);
+        id = dcaid_from_pcidev(pdev);
+
+        if (ioatdca->requester_count == ioatdca->max_requesters)
+                return -ENODEV;
+
+        for (i = 0; i < ioatdca->max_requesters; i++) {
+                if (ioatdca->req_slots[i].pdev == NULL) {
+                        /* found an empty slot */
+                        ioatdca->requester_count++;
+                        ioatdca->req_slots[i].pdev = pdev;
+                        ioatdca->req_slots[i].rid = id;
+                        global_req_table =
+                              readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET);
+                        writel(id | IOAT_DCA_GREQID_VALID,
+                               ioatdca->iobase + global_req_table + (i * 4));
+                        return i;
+                }
+        }
+        /* Error, ioatdma->requester_count is out of whack */
+        return -EFAULT;
+}
+
+static int ioat3_dca_remove_requester(struct dca_provider *dca,
+                                      struct device *dev)
+{
+        struct ioat_dca_priv *ioatdca = dca_priv(dca);
+        struct pci_dev *pdev;
+        int i;
+        u16 global_req_table;
+
+        /* This implementation only supports PCI-Express */
+        if (dev->bus != &pci_bus_type)
+                return -ENODEV;
+        pdev = to_pci_dev(dev);
+
+        for (i = 0; i < ioatdca->max_requesters; i++) {
+                if (ioatdca->req_slots[i].pdev == pdev) {
+                        global_req_table =
+                              readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET);
+                        writel(0, ioatdca->iobase + global_req_table + (i * 4));
+                        ioatdca->req_slots[i].pdev = NULL;
+                        ioatdca->req_slots[i].rid = 0;
+                        ioatdca->requester_count--;
+                        return i;
+                }
+        }
+        return -ENODEV;
+}
+
+static u8 ioat3_dca_get_tag(struct dca_provider *dca,
+                            struct device *dev,
+                            int cpu)
+{
+        u8 tag;
+
+        struct ioat_dca_priv *ioatdca = dca_priv(dca);
+        int i, apic_id, bit, value;
+        u8 entry;
+
+        tag = 0;
+        apic_id = cpu_physical_id(cpu);
+
+        for (i = 0; i < IOAT_TAG_MAP_LEN; i++) {
+                entry = ioatdca->tag_map[i];
+                if (entry & DCA3_TAG_MAP_BIT_TO_SEL) {
+                        bit = entry &
+                                ~(DCA3_TAG_MAP_BIT_TO_SEL | DCA3_TAG_MAP_BIT_TO_INV);
+                        value = (apic_id & (1 << bit)) ? 1 : 0;
+                } else if (entry & DCA3_TAG_MAP_BIT_TO_INV) {
+                        bit = entry & ~DCA3_TAG_MAP_BIT_TO_INV;
+                        value = (apic_id & (1 << bit)) ? 0 : 1;
+                } else {
+                        value = (entry & DCA3_TAG_MAP_LITERAL_VAL) ? 1 : 0;
+                }
+                tag |= (value << i);
+        }
+
+        return tag;
+}
+
+static struct dca_ops ioat3_dca_ops = {
+        .add_requester          = ioat3_dca_add_requester,
+        .remove_requester       = ioat3_dca_remove_requester,
+        .get_tag                = ioat3_dca_get_tag,
+        .dev_managed            = ioat_dca_dev_managed,
+};
+
+static int ioat3_dca_count_dca_slots(void *iobase, u16 dca_offset)
+{
+        int slots = 0;
+        u32 req;
+        u16 global_req_table;
+
+        global_req_table = readw(iobase + dca_offset + IOAT3_DCA_GREQID_OFFSET);
+        if (global_req_table == 0)
+                return 0;
+
+        do {
+                req = readl(iobase + global_req_table + (slots * sizeof(u32)));
+                slots++;
+        } while ((req & IOAT_DCA_GREQID_LASTID) == 0);
+
+        return slots;
+}
+
+struct dca_provider *ioat3_dca_init(struct pci_dev *pdev, void __iomem *iobase)
+{
+        struct dca_provider *dca;
+        struct ioat_dca_priv *ioatdca;
+        int slots;
+        int i;
+        int err;
+        u16 dca_offset;
+        u16 csi_fsb_control;
+        u16 pcie_control;
+        u8 bit;
+
+        union {
+                u64 full;
+                struct {
+                        u32 low;
+                        u32 high;
+                };
+        } tag_map;
+
+        if (!system_has_dca_enabled(pdev))
+                return NULL;
+
+        dca_offset = readw(iobase + IOAT_DCAOFFSET_OFFSET);
+        if (dca_offset == 0)
+                return NULL;
+
+        slots = ioat3_dca_count_dca_slots(iobase, dca_offset);
+        if (slots == 0)
+                return NULL;
+
+        dca = alloc_dca_provider(&ioat3_dca_ops,
+                                 sizeof(*ioatdca)
+                                      + (sizeof(struct ioat_dca_slot) * slots));
+        if (!dca)
+                return NULL;
+
+        ioatdca = dca_priv(dca);
+        ioatdca->iobase = iobase;
+        ioatdca->dca_base = iobase + dca_offset;
+        ioatdca->max_requesters = slots;
+
+        /* some bios might not know to turn these on */
+        csi_fsb_control = readw(ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET);
+        if ((csi_fsb_control & IOAT3_CSI_CONTROL_PREFETCH) == 0) {
+                csi_fsb_control |= IOAT3_CSI_CONTROL_PREFETCH;
+                writew(csi_fsb_control,
+                       ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET);
+        }
+        pcie_control = readw(ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET);
+        if ((pcie_control & IOAT3_PCI_CONTROL_MEMWR) == 0) {
+                pcie_control |= IOAT3_PCI_CONTROL_MEMWR;
+                writew(pcie_control,
+                       ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET);
+        }
+
+
+        /* TODO version, compatibility and configuration checks */
+
+        /* copy out the APIC to DCA tag map */
+        tag_map.low =
+                readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_LOW);
+        tag_map.high =
+                readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_HIGH);
+        for (i = 0; i < 8; i++) {
+                bit = tag_map.full >> (8 * i);
+                ioatdca->tag_map[i] = bit & DCA_TAG_MAP_MASK;
+        }
+
+        err = register_dca_provider(dca, &pdev->dev);
+        if (err) {
+                free_dca_provider(dca);
+                return NULL;
+        }
+
+        return dca;
+}
diff --git a/drivers/dma/ioat_dma.c b/drivers/dma/ioat_dma.c
index ece5a0e3a335..a52156e56886 100644
--- a/drivers/dma/ioat_dma.c
+++ b/drivers/dma/ioat_dma.c
@@ -53,6 +53,12 @@ MODULE_PARM_DESC(ioat_pending_level,
 static void ioat_dma_chan_reset_part2(struct work_struct *work);
 static void ioat_dma_chan_watchdog(struct work_struct *work);
 
+/*
+ * workaround for IOAT ver.3.0 null descriptor issue
+ * (channel returns error when size is 0)
+ */
+#define NULL_DESC_BUFFER_SIZE 1
+
 /* internal functions */
 static void ioat_dma_start_null_desc(struct ioat_dma_chan *ioat_chan);
 static void ioat_dma_memcpy_cleanup(struct ioat_dma_chan *ioat_chan);
@@ -129,6 +135,38 @@ static int ioat_dma_enumerate_channels(struct ioatdma_device *device)
         int i;
         struct ioat_dma_chan *ioat_chan;
 
+        /*
+         * IOAT ver.3 workarounds
+         */
+        if (device->version == IOAT_VER_3_0) {
+                u32 chan_err_mask;
+                u16 dev_id;
+                u32 dmauncerrsts;
+
+                /*
+                 * Write CHANERRMSK_INT with 3E07h to mask out the errors
+                 * that can cause stability issues for IOAT ver.3
+                 */
+                chan_err_mask = 0x3E07;
+                pci_write_config_dword(device->pdev,
+                        IOAT_PCI_CHANERRMASK_INT_OFFSET,
+                        chan_err_mask);
+
+                /*
+                 * Clear DMAUNCERRSTS Cfg-Reg Parity Error status bit
+                 * (workaround for spurious config parity error after restart)
+                 */
+                pci_read_config_word(device->pdev,
+                        IOAT_PCI_DEVICE_ID_OFFSET,
+                        &dev_id);
+                if (dev_id == PCI_DEVICE_ID_INTEL_IOAT_TBG0) {
+                        dmauncerrsts = 0x10;
+                        pci_write_config_dword(device->pdev,
+                                IOAT_PCI_DMAUNCERRSTS_OFFSET,
+                                dmauncerrsts);
+                }
+        }
+
         device->common.chancnt = readb(device->reg_base + IOAT_CHANCNT_OFFSET);
         xfercap_scale = readb(device->reg_base + IOAT_XFERCAP_OFFSET);
         xfercap = (xfercap_scale == 0 ? -1 : (1UL << xfercap_scale));
@@ -473,6 +511,13 @@ static dma_cookie_t ioat1_tx_submit(struct dma_async_tx_descriptor *tx)
                 prev = new;
         } while (len && (new = ioat1_dma_get_next_descriptor(ioat_chan)));
 
+        if (!new) {
+                dev_err(&ioat_chan->device->pdev->dev,
+                        "tx submit failed\n");
+                spin_unlock_bh(&ioat_chan->desc_lock);
+                return -ENOMEM;
+        }
+
         hw->ctl = IOAT_DMA_DESCRIPTOR_CTL_CP_STS;
         if (new->async_tx.callback) {
                 hw->ctl |= IOAT_DMA_DESCRIPTOR_CTL_INT_GN;
@@ -558,7 +603,14 @@ static dma_cookie_t ioat2_tx_submit(struct dma_async_tx_descriptor *tx)
                 desc_count++;
         } while (len && (new = ioat2_dma_get_next_descriptor(ioat_chan)));
 
-        hw->ctl = IOAT_DMA_DESCRIPTOR_CTL_CP_STS;
+        if (!new) {
+                dev_err(&ioat_chan->device->pdev->dev,
+                        "tx submit failed\n");
+                spin_unlock_bh(&ioat_chan->desc_lock);
+                return -ENOMEM;
+        }
+
+        hw->ctl |= IOAT_DMA_DESCRIPTOR_CTL_CP_STS;
         if (new->async_tx.callback) {
                 hw->ctl |= IOAT_DMA_DESCRIPTOR_CTL_INT_GN;
                 if (first != new) {
@@ -629,6 +681,7 @@ static struct ioat_desc_sw *ioat_dma_alloc_descriptor(
                 desc_sw->async_tx.tx_submit = ioat1_tx_submit;
                 break;
         case IOAT_VER_2_0:
+        case IOAT_VER_3_0:
                 desc_sw->async_tx.tx_submit = ioat2_tx_submit;
                 break;
         }
@@ -779,6 +832,7 @@ static void ioat_dma_free_chan_resources(struct dma_chan *chan)
                 }
                 break;
         case IOAT_VER_2_0:
+        case IOAT_VER_3_0:
                 list_for_each_entry_safe(desc, _desc,
                                          ioat_chan->free_desc.next, node) {
                         list_del(&desc->node);
@@ -868,7 +922,8 @@ ioat2_dma_get_next_descriptor(struct ioat_dma_chan *ioat_chan)
 
                 /* set up the noop descriptor */
                 noop_desc = to_ioat_desc(ioat_chan->used_desc.next);
-                noop_desc->hw->size = 0;
+                /* set size to non-zero value (channel returns error when size is 0) */
+                noop_desc->hw->size = NULL_DESC_BUFFER_SIZE;
                 noop_desc->hw->ctl = IOAT_DMA_DESCRIPTOR_NUL;
                 noop_desc->hw->src_addr = 0;
                 noop_desc->hw->dst_addr = 0;
@@ -918,6 +973,7 @@ static struct ioat_desc_sw *ioat_dma_get_next_descriptor(
                 return ioat1_dma_get_next_descriptor(ioat_chan);
                 break;
         case IOAT_VER_2_0:
+        case IOAT_VER_3_0:
                 return ioat2_dma_get_next_descriptor(ioat_chan);
                 break;
         }
@@ -1061,10 +1117,12 @@ static void ioat_dma_memcpy_cleanup(struct ioat_dma_chan *ioat_chan)
                  * perhaps we're stuck so hard that the watchdog can't go off?
                  * try to catch it after 2 seconds
                  */
-                if (time_after(jiffies,
-                               ioat_chan->last_completion_time + HZ*WATCHDOG_DELAY)) {
-                        ioat_dma_chan_watchdog(&(ioat_chan->device->work.work));
-                        ioat_chan->last_completion_time = jiffies;
+                if (ioat_chan->device->version != IOAT_VER_3_0) {
+                        if (time_after(jiffies,
+                                       ioat_chan->last_completion_time + HZ*WATCHDOG_DELAY)) {
+                                ioat_dma_chan_watchdog(&(ioat_chan->device->work.work));
+                                ioat_chan->last_completion_time = jiffies;
+                        }
                 }
                 return;
         }
@@ -1120,6 +1178,7 @@ static void ioat_dma_memcpy_cleanup(struct ioat_dma_chan *ioat_chan)
                 }
                 break;
         case IOAT_VER_2_0:
+        case IOAT_VER_3_0:
                 /* has some other thread has already cleaned up? */
                 if (ioat_chan->used_desc.prev == NULL)
                         break;
@@ -1223,10 +1282,19 @@ static void ioat_dma_start_null_desc(struct ioat_dma_chan *ioat_chan)
         spin_lock_bh(&ioat_chan->desc_lock);
 
         desc = ioat_dma_get_next_descriptor(ioat_chan);
+
+        if (!desc) {
+                dev_err(&ioat_chan->device->pdev->dev,
+                        "Unable to start null desc - get next desc failed\n");
+                spin_unlock_bh(&ioat_chan->desc_lock);
+                return;
+        }
+
         desc->hw->ctl = IOAT_DMA_DESCRIPTOR_NUL
                                 | IOAT_DMA_DESCRIPTOR_CTL_INT_GN
                                 | IOAT_DMA_DESCRIPTOR_CTL_CP_STS;
-        desc->hw->size = 0;
+        /* set size to non-zero value (channel returns error when size is 0) */
+        desc->hw->size = NULL_DESC_BUFFER_SIZE;
         desc->hw->src_addr = 0;
         desc->hw->dst_addr = 0;
         async_tx_ack(&desc->async_tx);
@@ -1244,6 +1312,7 @@ static void ioat_dma_start_null_desc(struct ioat_dma_chan *ioat_chan)
                         + IOAT_CHANCMD_OFFSET(ioat_chan->device->version));
                 break;
         case IOAT_VER_2_0:
+        case IOAT_VER_3_0:
                 writel(((u64) desc->async_tx.phys) & 0x00000000FFFFFFFF,
                        ioat_chan->reg_base + IOAT2_CHAINADDR_OFFSET_LOW);
                 writel(((u64) desc->async_tx.phys) >> 32,
@@ -1562,6 +1631,7 @@ struct ioatdma_device *ioat_dma_probe(struct pci_dev *pdev,
                                                 ioat1_dma_memcpy_issue_pending;
                 break;
         case IOAT_VER_2_0:
+        case IOAT_VER_3_0:
                 device->common.device_prep_dma_memcpy = ioat2_dma_prep_memcpy;
                 device->common.device_issue_pending =
                                                 ioat2_dma_memcpy_issue_pending;
@@ -1585,9 +1655,11 @@ struct ioatdma_device *ioat_dma_probe(struct pci_dev *pdev,
 
         dma_async_device_register(&device->common);
 
-        INIT_DELAYED_WORK(&device->work, ioat_dma_chan_watchdog);
-        schedule_delayed_work(&device->work,
-                              WATCHDOG_DELAY);
+        if (device->version != IOAT_VER_3_0) {
+                INIT_DELAYED_WORK(&device->work, ioat_dma_chan_watchdog);
+                schedule_delayed_work(&device->work,
+                                      WATCHDOG_DELAY);
+        }
 
         return device;
 
@@ -1621,7 +1693,9 @@ void ioat_dma_remove(struct ioatdma_device *device)
         pci_release_regions(device->pdev);
         pci_disable_device(device->pdev);
 
-        cancel_delayed_work(&device->work);
+        if (device->version != IOAT_VER_3_0) {
+                cancel_delayed_work(&device->work);
+        }
 
         list_for_each_entry_safe(chan, _chan,
                                  &device->common.channels, device_node) {
diff --git a/drivers/dma/ioatdma.h b/drivers/dma/ioatdma.h
index 685adb62aa5a..a3306d0e1372 100644
--- a/drivers/dma/ioatdma.h
+++ b/drivers/dma/ioatdma.h
@@ -29,7 +29,7 @@
 #include <linux/pci_ids.h>
 #include <net/tcp.h>
 
-#define IOAT_DMA_VERSION  "2.18"
+#define IOAT_DMA_VERSION  "3.30"
 
 enum ioat_interrupt {
         none = 0,
@@ -135,6 +135,7 @@ static inline void ioat_set_tcp_copy_break(struct ioatdma_device *dev)
         #ifdef CONFIG_NET_DMA
         switch (dev->version) {
         case IOAT_VER_1_2:
+        case IOAT_VER_3_0:
                 sysctl_tcp_dma_copybreak = 4096;
                 break;
         case IOAT_VER_2_0:
@@ -150,11 +151,13 @@ struct ioatdma_device *ioat_dma_probe(struct pci_dev *pdev,
 void ioat_dma_remove(struct ioatdma_device *device);
 struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase);
 struct dca_provider *ioat2_dca_init(struct pci_dev *pdev, void __iomem *iobase);
+struct dca_provider *ioat3_dca_init(struct pci_dev *pdev, void __iomem *iobase);
 #else
 #define ioat_dma_probe(pdev, iobase)    NULL
 #define ioat_dma_remove(device)         do { } while (0)
 #define ioat_dca_init(pdev, iobase)     NULL
 #define ioat2_dca_init(pdev, iobase)    NULL
+#define ioat3_dca_init(pdev, iobase)    NULL
 #endif
 
 #endif /* IOATDMA_H */
diff --git a/drivers/dma/ioatdma_hw.h b/drivers/dma/ioatdma_hw.h
index dd470fa91d86..f1ae2c776f74 100644
--- a/drivers/dma/ioatdma_hw.h
+++ b/drivers/dma/ioatdma_hw.h
@@ -35,6 +35,7 @@
 #define IOAT_PCI_SID            0x8086
 #define IOAT_VER_1_2            0x12    /* Version 1.2 */
 #define IOAT_VER_2_0            0x20    /* Version 2.0 */
+#define IOAT_VER_3_0            0x30    /* Version 3.0 */
 
 struct ioat_dma_descriptor {
         uint32_t        size;
diff --git a/drivers/dma/ioatdma_registers.h b/drivers/dma/ioatdma_registers.h
index 9832d7ebd931..827cb503cac6 100644
--- a/drivers/dma/ioatdma_registers.h
+++ b/drivers/dma/ioatdma_registers.h
@@ -25,6 +25,10 @@
 #define IOAT_PCI_DMACTRL_DMA_EN                 0x00000001
 #define IOAT_PCI_DMACTRL_MSI_EN                 0x00000002
 
+#define IOAT_PCI_DEVICE_ID_OFFSET               0x02
+#define IOAT_PCI_DMAUNCERRSTS_OFFSET            0x148
+#define IOAT_PCI_CHANERRMASK_INT_OFFSET         0x184
+
 /* MMIO Device Registers */
 #define IOAT_CHANCNT_OFFSET                     0x00    /*  8-bit */
 
@@ -149,7 +153,23 @@
 #define IOAT_DCA_GREQID_VALID       0x20000000
 #define IOAT_DCA_GREQID_LASTID      0x80000000
 
+#define IOAT3_CSI_CAPABILITY_OFFSET 0x08
+#define IOAT3_CSI_CAPABILITY_PREFETCH    0x1
+
+#define IOAT3_PCI_CAPABILITY_OFFSET 0x0A
+#define IOAT3_PCI_CAPABILITY_MEMWR  0x1
+
+#define IOAT3_CSI_CONTROL_OFFSET    0x0C
+#define IOAT3_CSI_CONTROL_PREFETCH  0x1
+
+#define IOAT3_PCI_CONTROL_OFFSET    0x0E
+#define IOAT3_PCI_CONTROL_MEMWR     0x1
+
+#define IOAT3_APICID_TAG_MAP_OFFSET 0x10
+#define IOAT3_APICID_TAG_MAP_OFFSET_LOW  0x10
+#define IOAT3_APICID_TAG_MAP_OFFSET_HIGH 0x14
 
+#define IOAT3_DCA_GREQID_OFFSET     0x02
 
 #define IOAT1_CHAINADDR_OFFSET          0x0C    /* 64-bit Descriptor Chain Address Register */
 #define IOAT2_CHAINADDR_OFFSET          0x10    /* 64-bit Descriptor Chain Address Register */