[3.8.y.z extended stable] Patch "ioatdma: channel reset scheme fixup on Intel Atom S1200 platforms" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    ioatdma: channel reset scheme fixup on Intel Atom S1200 platforms

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.21.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 4d61ec9b5c2b41d853f7afae7611acec2e276fc6 Mon Sep 17 00:00:00 2001
From: Dave Jiang <dave.jiang at intel.com>
Date: Tue, 26 Mar 2013 15:42:47 -0700
Subject: ioatdma: channel reset scheme fixup on Intel Atom S1200 platforms

commit 8a52b9ff1154a68b6a2a8da9a31a87e52f5f6418 upstream.

BugLink: http://bugs.launchpad.net/bugs/1291113

The Intel Atom S1200 family ioatdma changed the channel reset behavior.
It does a reset similar to PCI FLR by resetting all the MSIX
registers. We have to re-init msix interrupts because of this. This
workaround is only specific to this platform and is not expected to carry
over to the later generations.

Signed-off-by: Dave Jiang <dave.jiang at intel.com>
Acked-by: Dan Williams <djbw at fb.com>
Signed-off-by: Vinod Koul <vinod.koul at intel.com>
(back ported from commit 8a52b9ff1154a68b6a2a8da9a31a87e52f5f6418)

[Tim Gardner] Back port notes: I implemented enough of this patch to support
device->irq_mode storage, upon which da87ca4d4ca101f177fffd84f1f0a5e4c0343557
(ioat: fix tasklet tear down) is dependent.

Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/dma/ioat/dma.c |  8 +++++++-
 drivers/dma/ioat/dma.h | 10 ++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index 1a68a8b..459e2ee 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -889,7 +889,7 @@ MODULE_PARM_DESC(ioat_interrupt_style,
  * ioat_dma_setup_interrupts - setup interrupt handler
  * @device: ioat device
  */
-static int ioat_dma_setup_interrupts(struct ioatdma_device *device)
+int ioat_dma_setup_interrupts(struct ioatdma_device *device)
 {
 	struct ioat_chan_common *chan;
 	struct pci_dev *pdev = device->pdev;
@@ -938,6 +938,7 @@ msix:
 		}
 	}
 	intrctrl |= IOAT_INTRCTRL_MSIX_VECTOR_CONTROL;
+	device->irq_mode = IOAT_MSIX;
 	goto done;

 msix_single_vector:
@@ -953,6 +954,7 @@ msix_single_vector:
 		pci_disable_msix(pdev);
 		goto msi;
 	}
+	device->irq_mode = IOAT_MSIX_SINGLE;
 	goto done;

 msi:
@@ -966,6 +968,7 @@ msi:
 		pci_disable_msi(pdev);
 		goto intx;
 	}
+	device->irq_mode = IOAT_MSIX;
 	goto done;

 intx:
@@ -974,6 +977,7 @@ intx:
 	if (err)
 		goto err_no_irq;

+	device->irq_mode = IOAT_INTX;
 done:
 	if (device->intr_quirk)
 		device->intr_quirk(device);
@@ -984,9 +988,11 @@ done:
 err_no_irq:
 	/* Disable all interrupt generation */
 	writeb(0, device->reg_base + IOAT_INTRCTRL_OFFSET);
+	device->irq_mode = IOAT_NOIRQ;
 	dev_err(dev, "no usable interrupts\n");
 	return err;
 }
+EXPORT_SYMBOL(ioat_dma_setup_interrupts);

 static void ioat_disable_interrupts(struct ioatdma_device *device)
 {
diff --git a/drivers/dma/ioat/dma.h b/drivers/dma/ioat/dma.h
index 087935f..84f91ce 100644
--- a/drivers/dma/ioat/dma.h
+++ b/drivers/dma/ioat/dma.h
@@ -48,6 +48,14 @@
  */
 #define NULL_DESC_BUFFER_SIZE 1

+enum ioat_irq_mode {
+	IOAT_NOIRQ = 0,
+	IOAT_MSIX,
+	IOAT_MSIX_SINGLE,
+	IOAT_MSI,
+	IOAT_INTX
+};
+
 /**
  * struct ioatdma_device - internal representation of a IOAT device
  * @pdev: PCI-Express device
@@ -77,6 +85,7 @@ struct ioatdma_device {
 	struct msix_entry msix_entries[4];
 	struct ioat_chan_common *idx[4];
 	struct dca_provider *dca;
+	enum ioat_irq_mode irq_mode;
 	void (*intr_quirk)(struct ioatdma_device *device);
 	int (*enumerate_channels)(struct ioatdma_device *device);
 	int (*reset_hw)(struct ioat_chan_common *chan);
@@ -320,6 +329,7 @@ bool ioat_cleanup_preamble(struct ioat_chan_common *chan,
 			   dma_addr_t *phys_complete);
 void ioat_kobject_add(struct ioatdma_device *device, struct kobj_type *type);
 void ioat_kobject_del(struct ioatdma_device *device);
+int ioat_dma_setup_interrupts(struct ioatdma_device *device);
 extern const struct sysfs_ops ioat_sysfs_ops;
 extern struct ioat_sysfs_entry ioat_version_attr;
 extern struct ioat_sysfs_entry ioat_cap_attr;
--
1.8.3.2