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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>
hifive-unleashed-5.1
Maciej Sosnowski 2009-02-26 11:04:23 +01:00 committed by Dan Williams
parent 1d93e52eb4
commit 49bc46360d
1 changed files with 24 additions and 0 deletions
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24
drivers/dma/ioat_dca.c
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@ -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);