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Commit 49bc4636 authored by Maciej Sosnowski's avatar Maciej Sosnowski Committed by Dan Williams
Browse files

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: default avatarMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: default avatarShannon Nelson <shannon.nelson@intel.com>
Acked-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 1d93e52e

drivers/dma/ioat_dca.c

+24 −0
Original line number Diff line number Diff line
@@ -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);