| Message ID | 20200508105304.14065-7-Sergey.Semin@baikalelectronics.ru (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | dmaengine: dw: Take Baikal-T1 SoC DW DMAC peculiarities into account | expand |
On Fri, May 08, 2020 at 01:53:04PM +0300, Serge Semin wrote: > Full multi-block transfers functionality is enabled in DW DMA > controller only if CHx_MULTI_BLK_EN is set. But LLP-based transfers > can be executed only if hardcode channel x LLP register feature isn't > enabled, which can be switched on at the IP core synthesis for > optimization. If it's enabled then the LLP register is hardcoded to > zero, so the blocks chaining based on the LLPs is unsupported. > This one is good. Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Feel free to reassemble the series, so, Vinod can apply it independently. > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> > Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> > Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> > Cc: Paul Burton <paulburton@kernel.org> > Cc: Ralf Baechle <ralf@linux-mips.org> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > Cc: Dan Williams <dan.j.williams@intel.com> > Cc: Rob Herring <robh+dt@kernel.org> > Cc: linux-mips@vger.kernel.org > Cc: devicetree@vger.kernel.org > > --- > > Changelog v2: > - Rearrange SoBs. > - Add comment about why hardware accelerated LLP list support depends > on both MBLK_EN and HC_LLP configs setting. > - Use explicit bits state comparison operator. > --- > drivers/dma/dw/core.c | 11 ++++++++++- > drivers/dma/dw/regs.h | 1 + > 2 files changed, 11 insertions(+), 1 deletion(-) > > diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c > index 5b76ccc857fd..3179d45df662 100644 > --- a/drivers/dma/dw/core.c > +++ b/drivers/dma/dw/core.c > @@ -1180,8 +1180,17 @@ int do_dma_probe(struct dw_dma_chip *chip) > */ > dwc->block_size = > (4 << ((pdata->block_size >> 4 * i) & 0xf)) - 1; > + > + /* > + * According to the DW DMA databook the true scatter- > + * gether LLPs aren't available if either multi-block > + * config is disabled (CHx_MULTI_BLK_EN == 0) or the > + * LLP register is hard-coded to zeros > + * (CHx_HC_LLP == 1). > + */ > dwc->nollp = > - (dwc_params >> DWC_PARAMS_MBLK_EN & 0x1) == 0; > + (dwc_params >> DWC_PARAMS_MBLK_EN & 0x1) == 0 || > + (dwc_params >> DWC_PARAMS_HC_LLP & 0x1) == 1; > dwc->max_burst = > (0x4 << (dwc_params >> DWC_PARAMS_MSIZE & 0x7)); > } else { > diff --git a/drivers/dma/dw/regs.h b/drivers/dma/dw/regs.h > index f581d4809b71..a8af19d0eabd 100644 > --- a/drivers/dma/dw/regs.h > +++ b/drivers/dma/dw/regs.h > @@ -126,6 +126,7 @@ struct dw_dma_regs { > > /* Bitfields in DWC_PARAMS */ > #define DWC_PARAMS_MSIZE 16 /* max group transaction size */ > +#define DWC_PARAMS_HC_LLP 13 /* set LLP register to zero */ > #define DWC_PARAMS_MBLK_EN 11 /* multi block transfer */ > > /* bursts size */ > -- > 2.25.1 >
diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c index 5b76ccc857fd..3179d45df662 100644 --- a/drivers/dma/dw/core.c +++ b/drivers/dma/dw/core.c @@ -1180,8 +1180,17 @@ int do_dma_probe(struct dw_dma_chip *chip) */ dwc->block_size = (4 << ((pdata->block_size >> 4 * i) & 0xf)) - 1; + + /* + * According to the DW DMA databook the true scatter- + * gether LLPs aren't available if either multi-block + * config is disabled (CHx_MULTI_BLK_EN == 0) or the + * LLP register is hard-coded to zeros + * (CHx_HC_LLP == 1). + */ dwc->nollp = - (dwc_params >> DWC_PARAMS_MBLK_EN & 0x1) == 0; + (dwc_params >> DWC_PARAMS_MBLK_EN & 0x1) == 0 || + (dwc_params >> DWC_PARAMS_HC_LLP & 0x1) == 1; dwc->max_burst = (0x4 << (dwc_params >> DWC_PARAMS_MSIZE & 0x7)); } else { diff --git a/drivers/dma/dw/regs.h b/drivers/dma/dw/regs.h index f581d4809b71..a8af19d0eabd 100644 --- a/drivers/dma/dw/regs.h +++ b/drivers/dma/dw/regs.h @@ -126,6 +126,7 @@ struct dw_dma_regs { /* Bitfields in DWC_PARAMS */ #define DWC_PARAMS_MSIZE 16 /* max group transaction size */ +#define DWC_PARAMS_HC_LLP 13 /* set LLP register to zero */ #define DWC_PARAMS_MBLK_EN 11 /* multi block transfer */ /* bursts size */
Full multi-block transfers functionality is enabled in DW DMA controller only if CHx_MULTI_BLK_EN is set. But LLP-based transfers can be executed only if hardcode channel x LLP register feature isn't enabled, which can be switched on at the IP core synthesis for optimization. If it's enabled then the LLP register is hardcoded to zero, so the blocks chaining based on the LLPs is unsupported. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Paul Burton <paulburton@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org --- Changelog v2: - Rearrange SoBs. - Add comment about why hardware accelerated LLP list support depends on both MBLK_EN and HC_LLP configs setting. - Use explicit bits state comparison operator. --- drivers/dma/dw/core.c | 11 ++++++++++- drivers/dma/dw/regs.h | 1 + 2 files changed, 11 insertions(+), 1 deletion(-)