xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

dmaengine: dw: Introduce max burst length hw config

Browse Source 
IP core of the DW DMA controller may be synthesized with different
max burst length of the transfers per each channel. According to Synopsis
having the fixed maximum burst transactions length may provide some
performance gain. At the same time setting up the source and destination
multi size exceeding the max burst length limitation may cause a serious
problems. In our case the DMA transaction just hangs up. In order to fix
this lets introduce the max burst length platform config of the DW DMA
controller device and don't let the DMA channels configuration code
exceed the burst length hardware limitation.

Note the maximum burst length parameter can be detected either in runtime
from the DWC parameter registers or from the dedicated DT property.
Depending on the IP core configuration the maximum value can vary from
channel to channel so by overriding the channel slave max_burst capability
we make sure a DMA consumer will get the channel-specific max burst
length.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200723005848.31907-10-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Serge Semin
2020-07-23 03:58:47 +03:00
committed by Vinod Koul
parent 585d35451e
commit ca7f285171
4 changed files with 26 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
include/linux/platform_data/dma-dw.h
View File

@@ -44,6 +44,8 @@ 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.
* @max_burst: Maximum value of burst transaction size supported by hardware
* per channel (in units of CTL.SRC_TR_WIDTH/CTL.DST_TR_WIDTH).
* @protctl: Protection control signals setting per channel.
*/
struct dw_dma_platform_data {
@@ -58,6 +60,7 @@ 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];
u32 max_burst[DW_DMA_MAX_NR_CHANNELS];
#define CHAN_PROTCTL_PRIVILEGED BIT(0)
#define CHAN_PROTCTL_BUFFERABLE BIT(1)
#define CHAN_PROTCTL_CACHEABLE BIT(2)