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path: root/drivers/dma/ioat_dca.c
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Diffstat (limited to 'drivers/dma/ioat_dca.c')
-rw-r--r--drivers/dma/ioat_dca.c26
1 files changed, 25 insertions, 1 deletions
diff --git a/drivers/dma/ioat_dca.c b/drivers/dma/ioat_dca.c
index 6cf622da0286..c012a1e15043 100644
--- a/drivers/dma/ioat_dca.c
+++ b/drivers/dma/ioat_dca.c
@@ -1,6 +1,6 @@
/*
* Intel I/OAT DMA Linux driver
- * Copyright(c) 2007 Intel Corporation.
+ * Copyright(c) 2007 - 2009 Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
@@ -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);