lkml.org 
[lkml]   [2020]   [Jun]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[PATCH v2 0/2] introduce fallback to pio in spi core
Date
Introudce fallback pio way at spi core level so that the tx/rx buffer
mapped by spi core for dma could be unmap and fallback pio again. Hence no
need the below patch where 'dma_sync_sg_for_devic' to sync fresh data back
into 'device' memory and sync to 'cpu' again in spi core.
https://www.spinics.net/lists/arm-kernel/msg812236.html

If you want to use this fallback feature, please set xfer->error with
SPI_TRANS_FAIL_NO_START in case dma transfer failed(but no any data push
into spi bus yet) in spi client driver and add 'master->fallback' checking
in your can_dma() to ensure spi core can fallback to pio next time.

change from:
v2:
1. Add error flag in stuct spi_transfer and fallback to pio if spi client
return SPI_TRANS_FAIL_NO_START failure before dma transfer start.
2. Remove SPI_MASTER_FALLBACK set on master->flags since the above error
flag could ensure no any impact for other spi client drivers which don't
need this feature.

Robin Gong (2):
spi: introduce fallback to pio
spi: imx: add fallback feature

drivers/spi/spi-imx.c | 23 +++++------------------
drivers/spi/spi.c | 11 +++++++++++
include/linux/spi/spi.h | 4 ++++
3 files changed, 20 insertions(+), 18 deletions(-)

--
2.7.4

\
 
 \ /
  Last update: 2020-06-16 16:42    [W:0.054 / U:0.844 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site