I/OAT: Add support for version 2 of ioatdma device

Add support for version 2 of the ioatdma device.  This device handles
the descriptor chain and DCA services slightly differently:
 - Instead of moving the dma descriptors between a busy and an idle chain,
   this new version uses a single circular chain so that we don't have
   rewrite the next_descriptor pointers as we add new requests, and the
   device doesn't need to re-read the last descriptor.
 - The new device has the DCA tags defined internally instead of needing
   them defined statically.

Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Cc: "Williams, Dan J" <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 164 insertions, 0 deletions

diff --git a/drivers/dma/ioat_dca.c b/drivers/dma/ioat_dca.c
index ba985715b803..0fa8a98051a8 100644
--- a/drivers/dma/ioat_dca.c
+++ b/drivers/dma/ioat_dca.c
@@ -261,3 +261,167 @@ struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase)
         return dca;
 }
 
+
+static int ioat2_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 + IOAT_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 ioat2_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 + IOAT_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 ioat2_dca_get_tag(struct dca_provider *dca, int cpu)
+{
+        u8 tag;
+
+        tag = ioat_dca_get_tag(dca, cpu);
+        tag = (~tag) & 0x1F;
+        return tag;
+}
+
+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,
+};
+
+static int ioat2_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 + IOAT_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 *ioat2_dca_init(struct pci_dev *pdev, void __iomem *iobase)
+{
+        struct dca_provider *dca;
+        struct ioat_dca_priv *ioatdca;
+        int slots;
+        int i;
+        int err;
+        u32 tag_map;
+        u16 dca_offset;
+        u16 csi_fsb_control;
+        u16 pcie_control;
+        u8 bit;
+
+        if (!system_has_dca_enabled(pdev))
+                return NULL;
+
+        dca_offset = readw(iobase + IOAT_DCAOFFSET_OFFSET);
+        if (dca_offset == 0)
+                return NULL;
+
+        slots = ioat2_dca_count_dca_slots(iobase, dca_offset);
+        if (slots == 0)
+                return NULL;
+
+        dca = alloc_dca_provider(&ioat2_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 + IOAT_FSB_CAP_ENABLE_OFFSET);
+        if ((csi_fsb_control & IOAT_FSB_CAP_ENABLE_PREFETCH) == 0) {
+                csi_fsb_control |= IOAT_FSB_CAP_ENABLE_PREFETCH;
+                writew(csi_fsb_control,
+                       ioatdca->dca_base + IOAT_FSB_CAP_ENABLE_OFFSET);
+        }
+        pcie_control = readw(ioatdca->dca_base + IOAT_PCI_CAP_ENABLE_OFFSET);
+        if ((pcie_control & IOAT_PCI_CAP_ENABLE_MEMWR) == 0) {
+                pcie_control |= IOAT_PCI_CAP_ENABLE_MEMWR;
+                writew(pcie_control,
+                       ioatdca->dca_base + IOAT_PCI_CAP_ENABLE_OFFSET);
+        }
+
+
+        /* TODO version, compatibility and configuration checks */
+
+        /* copy out the APIC to DCA tag map */
+        tag_map = readl(ioatdca->dca_base + IOAT_APICID_TAG_MAP_OFFSET);
+        for (i = 0; i < 5; i++) {
+                bit = (tag_map >> (4 * i)) & 0x0f;
+                if (bit < 8)
+                        ioatdca->tag_map[i] = bit | DCA_TAG_MAP_VALID;
+                else
+                        ioatdca->tag_map[i] = 0;
+        }
+
+        err = register_dca_provider(dca, &pdev->dev);
+        if (err) {
+                free_dca_provider(dca);
+                return NULL;
+        }
+
+        return dca;
+}