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. 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") Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Signed-off-by: Christian Lamparter <chunkeey@xxxxxxxxx> --- I've included the "LGTM" from Andy from the v2 series and transformed it into a reviewed-by tag. --- 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 d0c3e50b39fb..2c5ca1961256 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 f01b2c173fa6..31ff8113c3de 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..1a1d58ebffbf 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) + unsigned char protctl; }; #endif /* _PLATFORM_DATA_DMA_DW_H */ -- 2.19.1
