diff options
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/ioat_dca.c | 24 |
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); |