scsi: hisi_sas: workaround a SoC SATA IO processing bug

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This patch provides a workaround a SoC bug where SATA IPTTs for
different devices may conflict.

The workaround solution requests the following:
1. SATA device id must be even and not equal to SAS IPTT.
2. SATA device can not share the same IPTT with other SAS or
   SATA device.

Besides we shall consider IPTT value 0 is reserved for another SoC bug
(STP device open link at firstly after SAS controller reset).

To sum up, the solution is: Each SATA device uses independent and
continuous 32 even IPTT from 64 to 4094, then v2 hw can only support 63
SATA devices.  All SAS device(SSP/SMP devices) share odd IPTT value from
1 to 4095.

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

...

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Xiaofei Tan 2017-04-10 21:21:57 +08:00 • committed by Martin K. Petersen

parent c7b9d369e4

commit 32ccba52f1

2 changed files with 72 additions and 13 deletions

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2

drivers/scsi/hisi_sas/hisi_sas.h

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83

drivers/scsi/hisi_sas/hisi_sas_v2_hw.c

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