On 08/10/2016 12:19 PM, Tom Yan wrote:
On 10 August 2016 at 15:41, David Milburn <dmilburn@xxxxxxxxxx> wrote:
Hi,
The 168 makes AHCI_CMD_TBL_SZ equal to 2816
AHCI_CMD_TBL_SZ = AHCI_CMD_TBL_HDR_SZ + (AHCI_MAX_SG * 16)
AHCI_CMD_TBL_SZ = 128 + (168 * 16)
I think if you add in AHCI_CMD_SLOT_SZ (1024) and AHCI_RX_FIS_SZ (256)
the DMA is 4K aligned, I think that is where the 168 came from.
Looks like the right guess. Though AHCI_PORT_PRIV_DMA_SZ is not:
AHCI_CMD_SLOT_SZ (1024) + AHCI_CMD_TBL_SZ (2816) + AHCI_RX_FIS_SZ (256) = 4096
but:
AHCI_CMD_SLOT_SZ (1024) + AHCI_CMD_TBL_AR_SZ (2816 * 32 = 90112) +
AHCI_RX_FIS_SZ (256) = 91392
and AHCI_PORT_PRIV_FBS_DMA_SZ is:
AHCI_CMD_SLOT_SZ (1024) + AHCI_CMD_TBL_AR_SZ (2816 * 32 = 90112) +
AHCI_RX_FIS_SZ * 16 (4096) = 95232
Yes, but in both cases mem_dma gets adjusted for AHCI_CMD_SLOT_SZ (1024)
and rx_fis_sz (256 or 4096 in fbs case).
Thanks,
David
--
To unsubscribe from this list: send the line "unsubscribe linux-block" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
