Hi, > From: Serge Semin, Sent: Friday, June 10, 2022 6:15 PM > > Instead of splitting the 64-bits IOs up into two 32-bits ones it's > possible to use an available set of the non-atomic readq/writeq methods > implemented exactly for such cases. They are defined in the dedicated > header files io-64-nonatomic-lo-hi.h/io-64-nonatomic-hi-lo.h. So in case > if the 64-bits readq/writeq methods are unavailable on some platforms at > consideration, the corresponding drivers can have any of these headers > included and stop locally re-implementing the 64-bits IO accessors taking > into account the non-atomic nature of the included methods. Let's do that > in the DW eDMA driver too. Note by doing so we can discard the > CONFIG_64BIT config ifdefs from the code. Also note that if a platform > doesn't support 64-bit DBI IOs then the corresponding accessors will just > directly call the lo_hi_readq()/lo_hi_writeq() methods. > > Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > --- > drivers/dma/dw-edma/dw-edma-v0-core.c | 71 +++++++++------------------ > 1 file changed, 24 insertions(+), 47 deletions(-) > > diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c > index e6d611176891..4348d2323125 100644 > --- a/drivers/dma/dw-edma/dw-edma-v0-core.c > +++ b/drivers/dma/dw-edma/dw-edma-v0-core.c <snip> > @@ -417,18 +404,8 @@ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first) > SET_CH_32(dw, chan->dir, chan->id, ch_control1, > (DW_EDMA_V0_CCS | DW_EDMA_V0_LLE)); > /* Linked list */ > - if ((chan->dw->chip->flags & DW_EDMA_CHIP_32BIT_DBI) || I'm trying to use this patch series, but I could not apply this patch. I investigated why, and then IIUC the DW_EDMA_CHIP_32BIT_DBI flag doesn't exist on the following based patches: https://patchwork.kernel.org/project/linux-pci/cover/20220624143947.8991-1-Sergey.Semin@xxxxxxxxxxxxxxxxxxxx/ https://patchwork.kernel.org/project/linux-dmaengine/cover/20220524152159.2370739-1-Frank.Li@xxxxxxx/ According to the comment from Zhi Li [1], the flag can be skipped by the fixed patch [2]. That's why the flag doesn't exist on the based patches. [1] https://patchwork.kernel.org/project/linux-dmaengine/patch/20220503005801.1714345-9-Frank.Li@xxxxxxx/#24844332 [2] https://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine.git/commit/?h=fixes&id=8fc5133d6d4da65cad6b73152fc714ad3d7f91c1 Since both codes in #ifdef and #else are the same, we can just remove code of the #else part. But, what do you think? ----- #ifdef CONFIG_64BIT /* llp is not aligned on 64bit -> keep 32bit accesses */ SET_CH_32(dw, chan->dir, chan->id, llp.lsb, lower_32_bits(chunk->ll_region.paddr)); SET_CH_32(dw, chan->dir, chan->id, llp.msb, upper_32_bits(chunk->ll_region.paddr)); #else /* CONFIG_64BIT */ SET_CH_32(dw, chan->dir, chan->id, llp.lsb, lower_32_bits(chunk->ll_region.paddr)); SET_CH_32(dw, chan->dir, chan->id, llp.msb, upper_32_bits(chunk->ll_region.paddr)); #endif /* CONFIG_64BIT */ ----- Best regards, Yoshihiro Shimoda > - !IS_ENABLED(CONFIG_64BIT)) { > - SET_CH_32(dw, chan->dir, chan->id, llp.lsb, > - lower_32_bits(chunk->ll_region.paddr)); > - SET_CH_32(dw, chan->dir, chan->id, llp.msb, > - upper_32_bits(chunk->ll_region.paddr)); > - } else { > - #ifdef CONFIG_64BIT > - SET_CH_64(dw, chan->dir, chan->id, llp.reg, > - chunk->ll_region.paddr); > - #endif > - } > + SET_CH_64(dw, chan->dir, chan->id, llp.reg, > + chunk->ll_region.paddr); > } > /* Doorbell */ > SET_RW_32(dw, chan->dir, doorbell, > -- > 2.35.1
