Re: [PATCH v3 3/4] dmaengine: Add Broadcom SBA RAID driver
From: Anup Patel
Date: Mon Feb 13 2017 - 23:00:12 EST
On Mon, Feb 13, 2017 at 2:43 PM, Anup Patel <anup.patel@xxxxxxxxxxxx> wrote:
> On Fri, Feb 10, 2017 at 11:20 PM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
>> On Fri, Feb 10, 2017 at 1:07 AM, Anup Patel <anup.patel@xxxxxxxxxxxx> wrote:
>>> The Broadcom stream buffer accelerator (SBA) provides offloading
>>> capabilities for RAID operations. This SBA offload engine is
>>> accessible via Broadcom SoC specific ring manager.
>>> This patch adds Broadcom SBA RAID driver which provides one
>>> DMA device with RAID capabilities using one or more Broadcom
>>> SoC specific ring manager channels. The SBA RAID driver in its
>>> current shape implements memcpy, xor, and pq operations.
>>> Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxxxx>
>>> Reviewed-by: Ray Jui <ray.jui@xxxxxxxxxxxx>
>>> drivers/dma/Kconfig | 13 +
>>> drivers/dma/Makefile | 1 +
>>> drivers/dma/bcm-sba-raid.c | 1711 ++++++++++++++++++++++++++++++++++++++++++++
>>> 3 files changed, 1725 insertions(+)
>>> create mode 100644 drivers/dma/bcm-sba-raid.c
>>> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
>>> index 263495d..bf8fb84 100644
>>> --- a/drivers/dma/Kconfig
>>> +++ b/drivers/dma/Kconfig
>>> @@ -99,6 +99,19 @@ config AXI_DMAC
>>> controller is often used in Analog Device's reference designs for FPGA
>>> +config BCM_SBA_RAID
>>> + tristate "Broadcom SBA RAID engine support"
>>> + depends on (ARM64 && MAILBOX && RAID6_PQ) || COMPILE_TEST
>>> + select DMA_ENGINE
>>> + select DMA_ENGINE_RAID
>>> + select ASYNC_TX_ENABLE_CHANNEL_SWITCH
>> ASYNC_TX_ENABLE_CHANNEL_SWITCH violates the DMA mapping API and
>> Russell has warned it's especially problematic on ARM . If you
>> need channel switching for this offload engine to be useful then you
>> need to move DMA mapping and channel switching responsibilities to MD
>> : http://lists.infradead.org/pipermail/linux-arm-kernel/2011-January/036753.html
> Actually driver works fine with/without
> ASYNC_TX_ENABLE_CHANNEL_SWITCH enabled
> so I am fine with removing dependency on this config option.
I stand corrected.
Previously, when I had tried removing
from BCM_SBA_RAID config option it worked because other
drivers such xgene-dma and mv_xor_v2 are selecting this option.
The BCM-SBA-RAID driver requires
There is no issue reported for
with ARM64 kernel.
The issue you pointed out was with ARM kernel.
We will have to select
for BCM-SBA-RAID driver
just like other ARM64 RAID drivers such
as xgene-dma and mv_xor_v2.
(Refer, XGENE_DMA and MV_XOR_V2 options)