diff options
Diffstat (limited to 'drivers/dma/ioat/dca.c')
| -rw-r--r-- | drivers/dma/ioat/dca.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/dma/ioat/dca.c b/drivers/dma/ioat/dca.c index abd9038e06b1..d6668071bd0d 100644 --- a/drivers/dma/ioat/dca.c +++ b/drivers/dma/ioat/dca.c @@ -604,6 +604,23 @@ static int ioat3_dca_count_dca_slots(void *iobase, u16 dca_offset) return slots; } +static inline int dca3_tag_map_invalid(u8 *tag_map) +{ + /* + * If the tag map is not programmed by the BIOS the default is: + * 0x80 0x80 0x80 0x80 0x80 0x00 0x00 0x00 + * + * This an invalid map and will result in only 2 possible tags + * 0x1F and 0x00. 0x00 is an invalid DCA tag so we know that + * this entire definition is invalid. + */ + return ((tag_map[0] == DCA_TAG_MAP_VALID) && + (tag_map[1] == DCA_TAG_MAP_VALID) && + (tag_map[2] == DCA_TAG_MAP_VALID) && + (tag_map[3] == DCA_TAG_MAP_VALID) && + (tag_map[4] == DCA_TAG_MAP_VALID)); +} + struct dca_provider * __devinit ioat3_dca_init(struct pci_dev *pdev, void __iomem *iobase) { @@ -674,6 +691,12 @@ ioat3_dca_init(struct pci_dev *pdev, void __iomem *iobase) ioatdca->tag_map[i] = bit & DCA_TAG_MAP_MASK; } + if (dca3_tag_map_invalid(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); |