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Ensure the controller's MDTS is accounted for in max_xfer_size.

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The controller's IDENTIFY data contains MDTS (Max Data Transfer Size) to
allow the controller to specify the maximum I/O data transfer size.  nvme(4)
already provides a default maximum, but make sure it does not exceed what
MDTS reports.

Sponsored by:	Intel
Reviewed by:	carl
This commit is contained in:
Jim Harris 2013-03-26 21:16:53 +00:00
parent cb5b7c1304
commit 02e3348484
2 changed files with 13 additions and 0 deletions
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10
sys/dev/nvme/nvme_ctrlr.c
View File

@ -457,6 +457,14 @@ nvme_ctrlr_identify(struct nvme_controller *ctrlr)
nvme_chatham_populate_cdata(ctrlr);
#endif
/*
* Use MDTS to ensure our default max_xfer_size doesn't exceed what the
* controller supports.
*/
if (ctrlr->cdata.mdts > 0)
ctrlr->max_xfer_size = min(ctrlr->max_xfer_size,
ctrlr->min_page_size * (1 << (ctrlr->cdata.mdts)));
return (0);
}
@ -923,6 +931,8 @@ nvme_ctrlr_construct(struct nvme_controller *ctrlr, device_t dev)
if (cap_hi.bits.dstrd != 0)
return (ENXIO);
ctrlr->min_page_size = 1 << (12 + cap_hi.bits.mpsmin);
/* Get ready timeout value from controller, in units of 500ms. */
cap_lo.raw = nvme_mmio_read_4(ctrlr, cap_lo);
ctrlr->ready_timeout_in_ms = cap_lo.bits.to * 500;

3
sys/dev/nvme/nvme_private.h
View File

@ -265,6 +265,9 @@ struct nvme_controller {
/** maximum i/o size in bytes */
uint32_t max_xfer_size;
/** minimum page size supported by this controller in bytes */
uint32_t min_page_size;
/** interrupt coalescing time period (in microseconds) */
uint32_t int_coal_time;