On Sat, Nov 10, 2018 at 05:28:31PM +0100, Christian Lamparter wrote: > This patch adds a new device-tree property that allows to > specify the dma protection control bits for the all of the > DMA controller's channel uniformly. > > Setting the "correct" bits can have a huge impact on the > PPC460EX and APM82181 that use this DMA engine in combination > with a DesignWare' SATA-II core (sata_dwc_460ex driver). > > In the OpenWrt Forum, the user takimata reported that: > |It seems your patch unleashed the full power of the SATA port. > |Where I was previously hitting a really hard limit at around > |82 MB/s for reading and 27 MB/s for writing, I am now getting this: > | > |root@OpenWrt:/mnt# time dd if=/dev/zero of=tempfile bs=1M count=1024 > |1024+0 records in > |1024+0 records out > |real 0m 13.65s > |user 0m 0.01s > |sys 0m 11.89s > | > |root@OpenWrt:/mnt# time dd if=tempfile of=/dev/null bs=1M count=1024 > |1024+0 records in > |1024+0 records out > |real 0m 8.41s > |user 0m 0.01s > |sys 0m 4.70s > | > |This means: 121 MB/s reading and 75 MB/s writing! > | > |The drive is a WD Green WD10EARX taken from an older MBL Single. > |I repeated the test a few times with even larger files to rule out > |any caching, I'm still seeing the same great performance. OpenWrt is > |now completely on par with the original MBL firmware's performance. > > Another user And.short reported: > |I can report that your fix worked! Boots up fine with two > |drives even with more partitions, and no more reboot on > |concurrent disk access! > > A closer look into the sata_dwc_460ex code revealed that > the driver did initally set the correct protection control > bits. However, this feature was lost when the sata_dwc_460ex > driver was converted to the generic DMA driver framework. LGTM, though minor style comment below. > > BugLink: https://forum.openwrt.org/t/wd-mybook-live-duo-two-disks/16195/55 > BugLink: https://forum.openwrt.org/t/wd-mybook-live-duo-two-disks/16195/50 > Fixes: 8b3444852a2b ("sata_dwc_460ex: move to generic DMA driver") > Signed-off-by: Christian Lamparter <chunkeey@xxxxxxxxx> > --- > drivers/dma/dw/core.c | 2 ++ > drivers/dma/dw/platform.c | 6 ++++++ > drivers/dma/dw/regs.h | 4 ++++ > include/linux/platform_data/dma-dw.h | 6 ++++++ > 4 files changed, 18 insertions(+) > > diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c > index f43e6dafe446..0772d2d6cc68 100644 > --- a/drivers/dma/dw/core.c > +++ b/drivers/dma/dw/core.c > @@ -160,12 +160,14 @@ static void dwc_initialize_chan_idma32(struct dw_dma_chan *dwc) > > static void dwc_initialize_chan_dw(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; > > cfghi |= DWC_CFGH_DST_PER(dwc->dws.dst_id); > cfghi |= DWC_CFGH_SRC_PER(dwc->dws.src_id); > + cfghi |= DWC_CFGH_PROTCTL(dw->pdata->protctl); > > /* Set polarity of handshake interface */ > cfglo |= hs_polarity ? DWC_CFGL_HS_DST_POL | DWC_CFGL_HS_SRC_POL : 0; > diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c > index f62dd0944908..c299ff181bb6 100644 > --- a/drivers/dma/dw/platform.c > +++ b/drivers/dma/dw/platform.c > @@ -162,6 +162,12 @@ dw_dma_parse_dt(struct platform_device *pdev) > pdata->multi_block[tmp] = 1; > } > > + if (!of_property_read_u32(np, "snps,dma-protection-control", &tmp)) { > + if (tmp > CHAN_PROTCTL_MASK) > + return NULL; > + pdata->protctl = tmp; > + } > + > return pdata; > } > #else > diff --git a/drivers/dma/dw/regs.h b/drivers/dma/dw/regs.h > index 09e7dfdbb790..646c9c960c07 100644 > --- a/drivers/dma/dw/regs.h > +++ b/drivers/dma/dw/regs.h > @@ -200,6 +200,10 @@ enum dw_dma_msize { > #define DWC_CFGH_FCMODE (1 << 0) > #define DWC_CFGH_FIFO_MODE (1 << 1) > #define DWC_CFGH_PROTCTL(x) ((x) << 2) > +#define DWC_CFGH_PROTCTL_DATA (0 << 2) /* data access - always set */ > +#define DWC_CFGH_PROTCTL_PRIV (1 << 2) /* privileged -> AHB HPROT[1] */ > +#define DWC_CFGH_PROTCTL_BUFFER (2 << 2) /* bufferable -> AHB HPROT[2] */ > +#define DWC_CFGH_PROTCTL_CACHE (4 << 2) /* cacheable -> AHB HPROT[3] */ > #define DWC_CFGH_DS_UPD_EN (1 << 5) > #define DWC_CFGH_SS_UPD_EN (1 << 6) > #define DWC_CFGH_SRC_PER(x) ((x) << 7) > diff --git a/include/linux/platform_data/dma-dw.h b/include/linux/platform_data/dma-dw.h > index 896cb71a382c..b7b9d4a56bb0 100644 > --- a/include/linux/platform_data/dma-dw.h > +++ b/include/linux/platform_data/dma-dw.h > @@ -49,6 +49,7 @@ 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. > + * @protctl: Protection control signals setting per channel. > */ > struct dw_dma_platform_data { > unsigned int nr_channels; > @@ -65,6 +66,11 @@ 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]; > +#define CHAN_PROTCTL_PRIVILEGED BIT(0) > +#define CHAN_PROTCTL_BUFFERABLE BIT(1) > +#define CHAN_PROTCTL_CACHEABLE BIT(2) > +#define CHAN_PROTCTL_MASK GENMASK(2, 0) TAB vs. SPACE. > + unsigned char protctl; > }; > > #endif /* _PLATFORM_DATA_DMA_DW_H */ > -- > 2.19.1 > -- With Best Regards, Andy Shevchenko
