Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

dmaengine: dw: set polarity of handshake interface

Browse source 
Intel Quark UART uses DesignWare DMA IP. Though the DMA IP is connected in such
way that handshake interface uses inverted polarity. We have to provide a
possibility to set this in the DMA driver when configuring a channel.

Introduce a new member of custom slave configuration called 'hs_polarity' and
set active low polarity in case this value is 'true'.

Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andy Shevchenko 2016-08-17 19:20:21 +03:00 committed by Greg Kroah-Hartman
parent 9217a5bf66
commit c072e113b8
2 changed files with 6 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
drivers/dma/dw/core.c
View file

@ -143,6 +143,7 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
struct dw_dma *dw = to_dw_dma(dwc->chan.device);
u32 cfghi = DWC_CFGH_FIFO_MODE;
u32 cfglo = DWC_CFGL_CH_PRIOR(dwc->priority);
bool hs_polarity = dwc->dws.hs_polarity;
if (test_bit(DW_DMA_IS_INITIALIZED, &dwc->flags))
return;
@ -150,6 +151,9 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
cfghi |= DWC_CFGH_DST_PER(dwc->dws.dst_id);
cfghi |= DWC_CFGH_SRC_PER(dwc->dws.src_id);
/* Set polarity of handshake interface */
cfglo |= hs_polarity ? DWC_CFGL_HS_DST_POL | DWC_CFGL_HS_SRC_POL : 0;
channel_writel(dwc, CFG_LO, cfglo);
channel_writel(dwc, CFG_HI, cfghi);

2
include/linux/platform_data/dma-dw.h
View file

@ -23,6 +23,7 @@
* @dst_id: dst request line
* @m_master: memory master for transfers on allocated channel
* @p_master: peripheral master for transfers on allocated channel
* @hs_polarity:set active low polarity of handshake interface
*/
struct dw_dma_slave {
struct device *dma_dev;
@ -30,6 +31,7 @@ struct dw_dma_slave {
u8 dst_id;
u8 m_master;
u8 p_master;
bool hs_polarity;
};
/**