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scsi: cxlflash: Reset hardware queue context via specified register

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Per the SISLite specification, context_reset() writes 0x1 to the LSB of the
reset register. When the AFU processes this reset request, it is expected
to clear the bit after reset is complete. The current implementation simply
checks that the entire value read back is not 1, instead of masking off the
LSB and evaluating it for a change to 0. Should the AFU manipulate other
bits during the reset (reading back a value of 0xF for example), successful
completion will be prematurely indicated given the existing logic.

Additionally, in the event that the context reset operation fails, there
does not currently exist a way to provide feedback to the initiator of the
reset. This poses a problem for the rare case that a context reset fails as
the caller will proceed on the assumption that all is well.

To remedy these issues, refactor the context reset routine to only mask off
the LSB when evaluating for success and return status to the caller. Also
update the context reset handler parameters to pass a hardware queue
reference instead of a single command to better reflect that the entire
queue associated with the context is impacted by the reset.

Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Uma Krishnan
2017-06-21 21:14:02 -05:00
committed by Martin K. Petersen
parent 539d890cec
commit a96851d337
2 changed files with 47 additions and 38 deletions
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2
drivers/scsi/cxlflash/common.h
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@@ -211,7 +211,7 @@ struct hwq {
struct afu {
struct hwq hwqs[CXLFLASH_MAX_HWQS];
int (*send_cmd)(struct afu *, struct afu_cmd *);
void (*context_reset)(struct afu_cmd *);
int (*context_reset)(struct hwq *);
/* AFU HW */
struct cxlflash_afu_map __iomem *afu_map; /* entire MMIO map */