I/OAT: Add support for MSI and MSI-X

Add support for MSI and MSI-X interrupt handling, including the ability
to choose the desired interrupt method.

Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>
[bunk@kernel.org: drivers/dma/ioat_dma.c: make 3 functions static]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 304 insertions, 66 deletions

diff --git a/drivers/dma/ioat_dma.c b/drivers/dma/ioat_dma.c
index eef83ea291a3..66c5bb53211b 100644
--- a/drivers/dma/ioat_dma.c
+++ b/drivers/dma/ioat_dma.c
@@ -47,6 +47,65 @@
 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);
 
+static struct ioat_dma_chan *ioat_lookup_chan_by_index(struct ioatdma_device *device,
+                                                       int index)
+{
+        return device->idx[index];
+}
+
+/**
+ * ioat_dma_do_interrupt - handler used for single vector interrupt mode
+ * @irq: interrupt id
+ * @data: interrupt data
+ */
+static irqreturn_t ioat_dma_do_interrupt(int irq, void *data)
+{
+        struct ioatdma_device *instance = data;
+        struct ioat_dma_chan *ioat_chan;
+        unsigned long attnstatus;
+        int bit;
+        u8 intrctrl;
+
+        intrctrl = readb(instance->reg_base + IOAT_INTRCTRL_OFFSET);
+
+        if (!(intrctrl & IOAT_INTRCTRL_MASTER_INT_EN))
+                return IRQ_NONE;
+
+        if (!(intrctrl & IOAT_INTRCTRL_INT_STATUS)) {
+                writeb(intrctrl, instance->reg_base + IOAT_INTRCTRL_OFFSET);
+                return IRQ_NONE;
+        }
+
+        attnstatus = readl(instance->reg_base + IOAT_ATTNSTATUS_OFFSET);
+        for_each_bit(bit, &attnstatus, BITS_PER_LONG) {
+                ioat_chan = ioat_lookup_chan_by_index(instance, bit);
+                tasklet_schedule(&ioat_chan->cleanup_task);
+        }
+
+        writeb(intrctrl, instance->reg_base + IOAT_INTRCTRL_OFFSET);
+        return IRQ_HANDLED;
+}
+
+/**
+ * ioat_dma_do_interrupt_msix - handler used for vector-per-channel interrupt mode
+ * @irq: interrupt id
+ * @data: interrupt data
+ */
+static irqreturn_t ioat_dma_do_interrupt_msix(int irq, void *data)
+{
+        struct ioat_dma_chan *ioat_chan = data;
+
+        tasklet_schedule(&ioat_chan->cleanup_task);
+
+        return IRQ_HANDLED;
+}
+
+static void ioat_dma_cleanup_tasklet(unsigned long data);
+
+/**
+ * ioat_dma_enumerate_channels - find and initialize the device's channels
+ * @device: the device to be enumerated
+ */
 static int ioat_dma_enumerate_channels(struct ioatdma_device *device)
 {
         u8 xfercap_scale;
@@ -76,6 +135,11 @@ static int ioat_dma_enumerate_channels(struct ioatdma_device *device)
                 ioat_chan->common.device = &device->common;
                 list_add_tail(&ioat_chan->common.device_node,
                               &device->common.channels);
+                device->idx[i] = ioat_chan;
+                tasklet_init(&ioat_chan->cleanup_task,
+                             ioat_dma_cleanup_tasklet,
+                             (unsigned long) ioat_chan);
+                tasklet_disable(&ioat_chan->cleanup_task);
         }
         return device->common.chancnt;
 }
@@ -234,6 +298,7 @@ static int ioat_dma_alloc_chan_resources(struct dma_chan *chan)
         writel(((u64) ioat_chan->completion_addr) >> 32,
                ioat_chan->reg_base + IOAT_CHANCMP_OFFSET_HIGH);
 
+        tasklet_enable(&ioat_chan->cleanup_task);
         ioat_dma_start_null_desc(ioat_chan);
         return i;
 }
@@ -245,9 +310,14 @@ static void ioat_dma_free_chan_resources(struct dma_chan *chan)
         struct ioat_desc_sw *desc, *_desc;
         int in_use_descs = 0;
 
+        tasklet_disable(&ioat_chan->cleanup_task);
         ioat_dma_memcpy_cleanup(ioat_chan);
 
+        /* Delay 100ms after reset to allow internal DMA logic to quiesce
+         * before removing DMA descriptor resources.
+         */
         writeb(IOAT_CHANCMD_RESET, ioat_chan->reg_base + IOAT_CHANCMD_OFFSET);
+        mdelay(100);
 
         spin_lock_bh(&ioat_chan->desc_lock);
         list_for_each_entry_safe(desc, _desc, &ioat_chan->used_desc, node) {
@@ -276,6 +346,34 @@ static void ioat_dma_free_chan_resources(struct dma_chan *chan)
                         in_use_descs - 1);
 
         ioat_chan->last_completion = ioat_chan->completion_addr = 0;
+        ioat_chan->pending = 0;
+}
+/**
+ * ioat_dma_get_next_descriptor - return the next available descriptor
+ * @ioat_chan: IOAT DMA channel handle
+ *
+ * Gets the next descriptor from the chain, and must be called with the
+ * channel's desc_lock held.  Allocates more descriptors if the channel
+ * has run out.
+ */
+static struct ioat_desc_sw *ioat_dma_get_next_descriptor(
+                                                struct ioat_dma_chan *ioat_chan)
+{
+        struct ioat_desc_sw *new = NULL;
+
+        if (!list_empty(&ioat_chan->free_desc)) {
+                new = to_ioat_desc(ioat_chan->free_desc.next);
+                list_del(&new->node);
+        } else {
+                /* try to get another desc */
+                new = ioat_dma_alloc_descriptor(ioat_chan, GFP_ATOMIC);
+                /* will this ever happen? */
+                /* TODO add upper limit on these */
+                BUG_ON(!new);
+        }
+
+        prefetch(new->hw);
+        return new;
 }
 
 static struct dma_async_tx_descriptor *ioat_dma_prep_memcpy(
@@ -300,17 +398,7 @@ static struct dma_async_tx_descriptor *ioat_dma_prep_memcpy(
 
         spin_lock_bh(&ioat_chan->desc_lock);
         while (len) {
-                if (!list_empty(&ioat_chan->free_desc)) {
-                        new = to_ioat_desc(ioat_chan->free_desc.next);
-                        list_del(&new->node);
-                } else {
-                        /* try to get another desc */
-                        new = ioat_dma_alloc_descriptor(ioat_chan, GFP_ATOMIC);
-                        /* will this ever happen? */
-                        /* TODO add upper limit on these */
-                        BUG_ON(!new);
-                }
-
+                new = ioat_dma_get_next_descriptor(ioat_chan);
                 copy = min((u32) len, ioat_chan->xfercap);
 
                 new->hw->size = copy;
@@ -360,6 +448,14 @@ static void ioat_dma_memcpy_issue_pending(struct dma_chan *chan)
         }
 }
 
+static void ioat_dma_cleanup_tasklet(unsigned long data)
+{
+        struct ioat_dma_chan *chan = (void *)data;
+        ioat_dma_memcpy_cleanup(chan);
+        writew(IOAT_CHANCTRL_INT_DISABLE,
+               chan->reg_base + IOAT_CHANCTRL_OFFSET);
+}
+
 static void ioat_dma_memcpy_cleanup(struct ioat_dma_chan *ioat_chan)
 {
         unsigned long phys_complete;
@@ -397,6 +493,7 @@ static void ioat_dma_memcpy_cleanup(struct ioat_dma_chan *ioat_chan)
                 return;
         }
 
+        cookie = 0;
         spin_lock_bh(&ioat_chan->desc_lock);
         list_for_each_entry_safe(desc, _desc, &ioat_chan->used_desc, node) {
 
@@ -509,48 +606,13 @@ static enum dma_status ioat_dma_is_complete(struct dma_chan *chan,
 
 /* PCI API */
 
-static irqreturn_t ioat_do_interrupt(int irq, void *data)
-{
-        struct ioatdma_device *instance = data;
-        unsigned long attnstatus;
-        u8 intrctrl;
-
-        intrctrl = readb(instance->reg_base + IOAT_INTRCTRL_OFFSET);
-
-        if (!(intrctrl & IOAT_INTRCTRL_MASTER_INT_EN))
-                return IRQ_NONE;
-
-        if (!(intrctrl & IOAT_INTRCTRL_INT_STATUS)) {
-                writeb(intrctrl, instance->reg_base + IOAT_INTRCTRL_OFFSET);
-                return IRQ_NONE;
-        }
-
-        attnstatus = readl(instance->reg_base + IOAT_ATTNSTATUS_OFFSET);
-
-        printk(KERN_ERR "ioatdma: interrupt! status %lx\n", attnstatus);
-
-        writeb(intrctrl, instance->reg_base + IOAT_INTRCTRL_OFFSET);
-        return IRQ_HANDLED;
-}
-
 static void ioat_dma_start_null_desc(struct ioat_dma_chan *ioat_chan)
 {
         struct ioat_desc_sw *desc;
 
         spin_lock_bh(&ioat_chan->desc_lock);
 
-        if (!list_empty(&ioat_chan->free_desc)) {
-                desc = to_ioat_desc(ioat_chan->free_desc.next);
-                list_del(&desc->node);
-        } else {
-                /* try to get another desc */
-                spin_unlock_bh(&ioat_chan->desc_lock);
-                desc = ioat_dma_alloc_descriptor(ioat_chan, GFP_KERNEL);
-                spin_lock_bh(&ioat_chan->desc_lock);
-                /* will this ever happen? */
-                BUG_ON(!desc);
-        }
-
+        desc = ioat_dma_get_next_descriptor(ioat_chan);
         desc->hw->ctl = IOAT_DMA_DESCRIPTOR_NUL;
         desc->hw->next = 0;
         desc->async_tx.ack = 1;
@@ -571,7 +633,11 @@ static void ioat_dma_start_null_desc(struct ioat_dma_chan *ioat_chan)
  */
 #define IOAT_TEST_SIZE 2000
 
-static int ioat_self_test(struct ioatdma_device *device)
+/**
+ * ioat_dma_self_test - Perform a IOAT transaction to verify the HW works.
+ * @device: device to be tested
+ */
+static int ioat_dma_self_test(struct ioatdma_device *device)
 {
         int i;
         u8 *src;
@@ -639,6 +705,161 @@ out:
         return err;
 }
 
+static char ioat_interrupt_style[32] = "msix";
+module_param_string(ioat_interrupt_style, ioat_interrupt_style,
+                    sizeof(ioat_interrupt_style), 0644);
+MODULE_PARM_DESC(ioat_interrupt_style,
+                 "set ioat interrupt style: msix (default), "
+                 "msix-single-vector, msi, intx)");
+
+/**
+ * ioat_dma_setup_interrupts - setup interrupt handler
+ * @device: ioat device
+ */
+static int ioat_dma_setup_interrupts(struct ioatdma_device *device)
+{
+        struct ioat_dma_chan *ioat_chan;
+        int err, i, j, msixcnt;
+        u8 intrctrl = 0;
+
+        if (!strcmp(ioat_interrupt_style, "msix"))
+                goto msix;
+        if (!strcmp(ioat_interrupt_style, "msix-single-vector"))
+                goto msix_single_vector;
+        if (!strcmp(ioat_interrupt_style, "msi"))
+                goto msi;
+        if (!strcmp(ioat_interrupt_style, "intx"))
+                goto intx;
+
+msix:
+        /* The number of MSI-X vectors should equal the number of channels */
+        msixcnt = device->common.chancnt;
+        for (i = 0; i < msixcnt; i++)
+                device->msix_entries[i].entry = i;
+
+        err = pci_enable_msix(device->pdev, device->msix_entries, msixcnt);
+        if (err < 0)
+                goto msi;
+        if (err > 0)
+                goto msix_single_vector;
+
+        for (i = 0; i < msixcnt; i++) {
+                ioat_chan = ioat_lookup_chan_by_index(device, i);
+                err = request_irq(device->msix_entries[i].vector,
+                                  ioat_dma_do_interrupt_msix,
+                                  0, "ioat-msix", ioat_chan);
+                if (err) {
+                        for (j = 0; j < i; j++) {
+                                ioat_chan =
+                                        ioat_lookup_chan_by_index(device, j);
+                                free_irq(device->msix_entries[j].vector,
+                                         ioat_chan);
+                        }
+                        goto msix_single_vector;
+                }
+        }
+        intrctrl |= IOAT_INTRCTRL_MSIX_VECTOR_CONTROL;
+        device->irq_mode = msix_multi_vector;
+        goto done;
+
+msix_single_vector:
+        device->msix_entries[0].entry = 0;
+        err = pci_enable_msix(device->pdev, device->msix_entries, 1);
+        if (err)
+                goto msi;
+
+        err = request_irq(device->msix_entries[0].vector, ioat_dma_do_interrupt,
+                          0, "ioat-msix", device);
+        if (err) {
+                pci_disable_msix(device->pdev);
+                goto msi;
+        }
+        device->irq_mode = msix_single_vector;
+        goto done;
+
+msi:
+        err = pci_enable_msi(device->pdev);
+        if (err)
+                goto intx;
+
+        err = request_irq(device->pdev->irq, ioat_dma_do_interrupt,
+                          0, "ioat-msi", device);
+        if (err) {
+                pci_disable_msi(device->pdev);
+                goto intx;
+        }
+        /*
+         * CB 1.2 devices need a bit set in configuration space to enable MSI
+         */
+        if (device->version == IOAT_VER_1_2) {
+                u32 dmactrl;
+                pci_read_config_dword(device->pdev,
+                                      IOAT_PCI_DMACTRL_OFFSET, &dmactrl);
+                dmactrl |= IOAT_PCI_DMACTRL_MSI_EN;
+                pci_write_config_dword(device->pdev,
+                                       IOAT_PCI_DMACTRL_OFFSET, dmactrl);
+        }
+        device->irq_mode = msi;
+        goto done;
+
+intx:
+        err = request_irq(device->pdev->irq, ioat_dma_do_interrupt,
+                          IRQF_SHARED, "ioat-intx", device);
+        if (err)
+                goto err_no_irq;
+        device->irq_mode = intx;
+
+done:
+        intrctrl |= IOAT_INTRCTRL_MASTER_INT_EN;
+        writeb(intrctrl, device->reg_base + IOAT_INTRCTRL_OFFSET);
+        return 0;
+
+err_no_irq:
+        /* Disable all interrupt generation */
+        writeb(0, device->reg_base + IOAT_INTRCTRL_OFFSET);
+        dev_err(&device->pdev->dev, "no usable interrupts\n");
+        device->irq_mode = none;
+        return -1;
+}
+
+/**
+ * ioat_dma_remove_interrupts - remove whatever interrupts were set
+ * @device: ioat device
+ */
+static void ioat_dma_remove_interrupts(struct ioatdma_device *device)
+{
+        struct ioat_dma_chan *ioat_chan;
+        int i;
+
+        /* Disable all interrupt generation */
+        writeb(0, device->reg_base + IOAT_INTRCTRL_OFFSET);
+
+        switch (device->irq_mode) {
+        case msix_multi_vector:
+                for (i = 0; i < device->common.chancnt; i++) {
+                        ioat_chan = ioat_lookup_chan_by_index(device, i);
+                        free_irq(device->msix_entries[i].vector, ioat_chan);
+                }
+                pci_disable_msix(device->pdev);
+                break;
+        case msix_single_vector:
+                free_irq(device->msix_entries[0].vector, device);
+                pci_disable_msix(device->pdev);
+                break;
+        case msi:
+                free_irq(device->pdev->irq, device);
+                pci_disable_msi(device->pdev);
+                break;
+        case intx:
+                free_irq(device->pdev->irq, device);
+                break;
+        case none:
+                dev_warn(&device->pdev->dev,
+                         "call to %s without interrupts setup\n", __func__);
+        }
+        device->irq_mode = none;
+}
+
 struct ioatdma_device *ioat_dma_probe(struct pci_dev *pdev,
                                       void __iomem *iobase)
 {
@@ -684,21 +905,16 @@ struct ioatdma_device *ioat_dma_probe(struct pci_dev *pdev,
         device->common.device_issue_pending = ioat_dma_memcpy_issue_pending;
         device->common.device_dependency_added = ioat_dma_dependency_added;
         device->common.dev = &pdev->dev;
-        printk(KERN_INFO "ioatdma: Intel(R) I/OAT DMA Engine found,"
-               " %d channels, device version 0x%02x\n",
-               device->common.chancnt, device->version);
+        dev_err(&device->pdev->dev,
+                "ioatdma: Intel(R) I/OAT DMA Engine found,"
+                " %d channels, device version 0x%02x\n",
+                device->common.chancnt, device->version);
 
-        pci_set_drvdata(pdev, device);
-        err = request_irq(pdev->irq, &ioat_do_interrupt, IRQF_SHARED, "ioat",
-                device);
+        err = ioat_dma_setup_interrupts(device);
         if (err)
-                goto err_irq;
-
-        writeb(IOAT_INTRCTRL_MASTER_INT_EN,
-               device->reg_base + IOAT_INTRCTRL_OFFSET);
-        pci_set_master(pdev);
+                goto err_setup_interrupts;
 
-        err = ioat_self_test(device);
+        err = ioat_dma_self_test(device);
         if (err)
                 goto err_self_test;
 
@@ -707,8 +923,8 @@ struct ioatdma_device *ioat_dma_probe(struct pci_dev *pdev,
         return device;
 
 err_self_test:
-        free_irq(device->pdev->irq, device);
-err_irq:
+        ioat_dma_remove_interrupts(device);
+err_setup_interrupts:
         pci_pool_destroy(device->completion_pool);
 err_completion_pool:
         pci_pool_destroy(device->dma_pool);
@@ -716,8 +932,8 @@ err_dma_pool:
         kfree(device);
 err_kzalloc:
         iounmap(iobase);
-        printk(KERN_ERR
-               "ioatdma: Intel(R) I/OAT DMA Engine initialization failed\n");
+        dev_err(&device->pdev->dev,
+                "ioatdma: Intel(R) I/OAT DMA Engine initialization failed\n");
         return NULL;
 }
 
@@ -728,7 +944,7 @@ void ioat_dma_remove(struct ioatdma_device *device)
 
         dma_async_device_unregister(&device->common);
 
-        free_irq(device->pdev->irq, device);
+        ioat_dma_remove_interrupts(device);
 
         pci_pool_destroy(device->dma_pool);
         pci_pool_destroy(device->completion_pool);
diff --git a/drivers/dma/ioatdma.h b/drivers/dma/ioatdma.h
index 0b8ffbde1e61..2abf0b88a973 100644
--- a/drivers/dma/ioatdma.h
+++ b/drivers/dma/ioatdma.h
@@ -28,6 +28,14 @@
 #include <linux/cache.h>
 #include <linux/pci_ids.h>
 
+enum ioat_interrupt {
+        none = 0,
+        msix_multi_vector = 1,
+        msix_single_vector = 2,
+        msi = 3,
+        intx = 4,
+};
+
 #define IOAT_LOW_COMPLETION_MASK        0xffffffc0
 
 /**
@@ -46,6 +54,9 @@ struct ioatdma_device {
         struct pci_pool *completion_pool;
         struct dma_device common;
         u8 version;
+        enum ioat_interrupt irq_mode;
+        struct msix_entry msix_entries[4];
+        struct ioat_dma_chan *idx[4];
 };
 
 /**
@@ -94,6 +105,7 @@ struct ioat_dma_chan {
                         u32 high;
                 };
         } *completion_virt;
+        struct tasklet_struct cleanup_task;
 };
 
 /* wrapper around hardware descriptor format + additional software fields */
diff --git a/drivers/dma/ioatdma_registers.h b/drivers/dma/ioatdma_registers.h
index a30c7349075a..baaab5ea146a 100644
--- a/drivers/dma/ioatdma_registers.h
+++ b/drivers/dma/ioatdma_registers.h
@@ -1,5 +1,5 @@
 /*
- * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
+ * Copyright(c) 2004 - 2007 Intel Corporation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the Free
@@ -21,6 +21,9 @@
 #ifndef _IOAT_REGISTERS_H_
 #define _IOAT_REGISTERS_H_
 
+#define IOAT_PCI_DMACTRL_OFFSET                 0x48
+#define IOAT_PCI_DMACTRL_DMA_EN                 0x00000001
+#define IOAT_PCI_DMACTRL_MSI_EN                 0x00000002
 
 /* MMIO Device Registers */
 #define IOAT_CHANCNT_OFFSET                     0x00    /*  8-bit */
@@ -39,6 +42,7 @@
 #define IOAT_INTRCTRL_MASTER_INT_EN             0x01    /* Master Interrupt Enable */
 #define IOAT_INTRCTRL_INT_STATUS                0x02    /* ATTNSTATUS -or- Channel Int */
 #define IOAT_INTRCTRL_INT                       0x04    /* INT_STATUS -and- MASTER_INT_EN */
+#define IOAT_INTRCTRL_MSIX_VECTOR_CONTROL       0x08    /* Enable all MSI-X vectors */
 
 #define IOAT_ATTNSTATUS_OFFSET                  0x04    /* Each bit is a channel */
 
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 638165f571da..b9fb8ee3308b 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -8,6 +8,12 @@
  */
 #include <asm/bitops.h>
 
+#define for_each_bit(bit, addr, size) \
+        for ((bit) = find_first_bit((addr), (size)); \
+             (bit) < (size); \
+             (bit) = find_next_bit((addr), (size), (bit) + 1))
+
+
 static __inline__ int get_bitmask_order(unsigned int count)
 {
         int order;