diff options
| author | Christian Lamparter <chunkeey@gmail.com> | 2018-11-17 17:17:21 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-17 20:38:07 +0100 |
| commit | 2d91b55213fd41c116013dc39d9ec20f2011c9ea (patch) | |
| tree | 2d6a8c4ce5143f2562609f183ea77a07930f2add /include | |
| parent | 2a1723f99c3b9d19361b70660a29e0f93577a424 (diff) | |
dmaengine: dw-dmac: implement dma protection control setting
[ Upstream commit 7b0c03ecc42fb223baf015877fee9d517c2c8af1 ]
This patch adds a new device-tree property that allows to
specify the dma protection control bits for the all of the
DMA controller's channel uniformly.
Setting the "correct" bits can have a huge impact on the
PPC460EX and APM82181 that use this DMA engine in combination
with a DesignWare' SATA-II core (sata_dwc_460ex driver).
In the OpenWrt Forum, the user takimata reported that:
|It seems your patch unleashed the full power of the SATA port.
|Where I was previously hitting a really hard limit at around
|82 MB/s for reading and 27 MB/s for writing, I am now getting this:
|
|root@OpenWrt:/mnt# time dd if=/dev/zero of=tempfile bs=1M count=1024
|1024+0 records in
|1024+0 records out
|real 0m 13.65s
|user 0m 0.01s
|sys 0m 11.89s
|
|root@OpenWrt:/mnt# time dd if=tempfile of=/dev/null bs=1M count=1024
|1024+0 records in
|1024+0 records out
|real 0m 8.41s
|user 0m 0.01s
|sys 0m 4.70s
|
|This means: 121 MB/s reading and 75 MB/s writing!
|
|The drive is a WD Green WD10EARX taken from an older MBL Single.
|I repeated the test a few times with even larger files to rule out
|any caching, I'm still seeing the same great performance. OpenWrt is
|now completely on par with the original MBL firmware's performance.
Another user And.short reported:
|I can report that your fix worked! Boots up fine with two
|drives even with more partitions, and no more reboot on
|concurrent disk access!
A closer look into the sata_dwc_460ex code revealed that
the driver did initally set the correct protection control
bits. However, this feature was lost when the sata_dwc_460ex
driver was converted to the generic DMA driver framework.
BugLink: https://forum.openwrt.org/t/wd-mybook-live-duo-two-disks/16195/55
BugLink: https://forum.openwrt.org/t/wd-mybook-live-duo-two-disks/16195/50
Fixes: 8b3444852a2b ("sata_dwc_460ex: move to generic DMA driver")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/platform_data/dma-dw.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/platform_data/dma-dw.h b/include/linux/platform_data/dma-dw.h index 896cb71a382c..1a1d58ebffbf 100644 --- a/include/linux/platform_data/dma-dw.h +++ b/include/linux/platform_data/dma-dw.h @@ -49,6 +49,7 @@ struct dw_dma_slave { * @data_width: Maximum data width supported by hardware per AHB master * (in bytes, power of 2) * @multi_block: Multi block transfers supported by hardware per channel. + * @protctl: Protection control signals setting per channel. */ struct dw_dma_platform_data { unsigned int nr_channels; @@ -65,6 +66,11 @@ struct dw_dma_platform_data { unsigned char nr_masters; unsigned char data_width[DW_DMA_MAX_NR_MASTERS]; unsigned char multi_block[DW_DMA_MAX_NR_CHANNELS]; +#define CHAN_PROTCTL_PRIVILEGED BIT(0) +#define CHAN_PROTCTL_BUFFERABLE BIT(1) +#define CHAN_PROTCTL_CACHEABLE BIT(2) +#define CHAN_PROTCTL_MASK GENMASK(2, 0) + unsigned char protctl; }; #endif /* _PLATFORM_DATA_DMA_DW_H */ |