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authorMaciej Sosnowski <maciej.sosnowski@intel.com>2009-02-26 11:04:23 +0100
committerDan Williams <dan.j.williams@intel.com>2009-03-05 00:04:39 +0100
commit49bc46360d68156ce82b2b1a12badb80078453a0 (patch)
treedf7f187e26e3443384074376f52e47e516cf1bca
parentdmaengine: update kerneldoc (diff)
downloadlinux-49bc46360d68156ce82b2b1a12badb80078453a0.tar.xz
linux-49bc46360d68156ce82b2b1a12badb80078453a0.zip
I/OAT: add verification for proper APICID_TAG_MAP setting by BIOS
BIOS versions for systems with I/OAT ver.2 have been found which fail to program APICID_TAG_MAP for DCA. The ioatdma driver should recognize incorrectly set APICID_TAG_MAP and disable DCA in that case. Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Shannon Nelson <shannon.nelson@intel.com> Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
-rw-r--r--drivers/dma/ioat_dca.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/dma/ioat_dca.c b/drivers/dma/ioat_dca.c
index 6cf622da0286..78705ca7d36a 100644
--- a/drivers/dma/ioat_dca.c
+++ b/drivers/dma/ioat_dca.c
@@ -49,6 +49,23 @@
#define DCA_TAG_MAP_MASK 0xDF
+/* expected tag map bytes for I/OAT ver.2 */
+#define DCA2_TAG_MAP_BYTE0 0x80
+#define DCA2_TAG_MAP_BYTE1 0x0
+#define DCA2_TAG_MAP_BYTE2 0x81
+#define DCA2_TAG_MAP_BYTE3 0x82
+#define DCA2_TAG_MAP_BYTE4 0x82
+
+/* verify if tag map matches expected values */
+static inline int dca2_tag_map_valid(u8 *tag_map)
+{
+ return ((tag_map[0] == DCA2_TAG_MAP_BYTE0) &&
+ (tag_map[1] == DCA2_TAG_MAP_BYTE1) &&
+ (tag_map[2] == DCA2_TAG_MAP_BYTE2) &&
+ (tag_map[3] == DCA2_TAG_MAP_BYTE3) &&
+ (tag_map[4] == DCA2_TAG_MAP_BYTE4));
+}
+
/*
* "Legacy" DCA systems do not implement the DCA register set in the
* I/OAT device. Software needs direct support for their tag mappings.
@@ -452,6 +469,13 @@ struct dca_provider *ioat2_dca_init(struct pci_dev *pdev, void __iomem *iobase)
ioatdca->tag_map[i] = 0;
}
+ if (!dca2_tag_map_valid(ioatdca->tag_map)) {
+ dev_err(&pdev->dev, "APICID_TAG_MAP set incorrectly by BIOS, "
+ "disabling DCA\n");
+ free_dca_provider(dca);
+ return NULL;
+ }
+
err = register_dca_provider(dca, &pdev->dev);
if (err) {
free_dca_provider(dca);