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128 lines
4.7 KiB
128 lines
4.7 KiB
From 2aad36357bbc73bc88ebab35a59a70a8f4ae6ecb Mon Sep 17 00:00:00 2001
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From: Christian Lamparter <chunkeey@gmail.com>
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Date: Wed, 31 Oct 2018 22:27:27 +0100
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Subject: [PATCH 2/2] dmaengine: dw: implement per-channel protection control
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setting
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This patch adds a new device-tree property that allows to
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specify the protection control bits for each DMA channel
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individually.
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Setting the "correct" bits can have a huge impact on the
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PPC460EX and APM82181 that use this DMA engine in combination
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with a DesignWare' SATA-II core (sata_dwc_460ex driver).
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In the OpenWrt Forum, the user takimata reported that:
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|It seems your patch unleashed the full power of the SATA port.
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|Where I was previously hitting a really hard limit at around
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|82 MB/s for reading and 27 MB/s for writing, I am now getting this:
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|root@OpenWrt:/mnt# time dd if=/dev/zero of=tempfile bs=1M count=1024
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|1024+0 records in
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|1024+0 records out
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|real 0m 13.65s
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|user 0m 0.01s
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|sys 0m 11.89s
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|root@OpenWrt:/mnt# time dd if=tempfile of=/dev/null bs=1M count=1024
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|1024+0 records in
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|1024+0 records out
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|real 0m 8.41s
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|user 0m 0.01s
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|sys 0m 4.70s
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|This means: 121 MB/s reading and 75 MB/s writing!
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|The drive is a WD Green WD10EARX taken from an older MBL Single.
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|I repeated the test a few times with even larger files to rule out
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|any caching, I'm still seeing the same great performance. OpenWrt is
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|now completely on par with the original MBL firmware's performance.
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Another user And.short reported:
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|I can report that your fix worked! Boots up fine with two
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|drives even with more partitions, and no more reboot on
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|concurrent disk access!
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A closer look into the sata_dwc_460ex code revealed that
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the driver did initally set the correct protection control
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bits. However, this feature was lost when the sata_dwc_460ex
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driver was converted to the generic DMA driver framework.
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BugLink: https://forum.openwrt.org/t/wd-mybook-live-duo-two-disks/16195/55
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BugLink: https://forum.openwrt.org/t/wd-mybook-live-duo-two-disks/16195/50
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Fixes: 8b3444852a2b ("sata_dwc_460ex: move to generic DMA driver")
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Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
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---
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drivers/dma/dw/core.c | 2 ++
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drivers/dma/dw/platform.c | 12 +++++++++---
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drivers/dma/dw/regs.h | 4 ++++
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include/linux/platform_data/dma-dw.h | 6 ++++++
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4 files changed, 21 insertions(+), 3 deletions(-)
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--- a/drivers/dma/dw/core.c
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+++ b/drivers/dma/dw/core.c
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@@ -160,12 +160,14 @@ static void dwc_initialize_chan_idma32(s
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static void dwc_initialize_chan_dw(struct dw_dma_chan *dwc)
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{
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+ struct dw_dma *dw = to_dw_dma(dwc->chan.device);
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u32 cfghi = DWC_CFGH_FIFO_MODE;
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u32 cfglo = DWC_CFGL_CH_PRIOR(dwc->priority);
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bool hs_polarity = dwc->dws.hs_polarity;
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cfghi |= DWC_CFGH_DST_PER(dwc->dws.dst_id);
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cfghi |= DWC_CFGH_SRC_PER(dwc->dws.src_id);
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+ cfghi |= DWC_CFGH_PROTCTL(dw->pdata->protctl);
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/* Set polarity of handshake interface */
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cfglo |= hs_polarity ? DWC_CFGL_HS_DST_POL | DWC_CFGL_HS_SRC_POL : 0;
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--- a/drivers/dma/dw/platform.c
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+++ b/drivers/dma/dw/platform.c
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@@ -162,6 +162,12 @@ dw_dma_parse_dt(struct platform_device *
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pdata->multi_block[tmp] = 1;
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}
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+ if (!of_property_read_u32(np, "snps,dma-protection-control", &tmp)) {
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+ if (tmp > CHAN_PROTCTL_MASK)
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+ return NULL;
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+ pdata->protctl = tmp;
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+ }
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+
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return pdata;
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}
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#else
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--- a/drivers/dma/dw/regs.h
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+++ b/drivers/dma/dw/regs.h
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@@ -200,6 +200,10 @@ enum dw_dma_msize {
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#define DWC_CFGH_FCMODE (1 << 0)
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#define DWC_CFGH_FIFO_MODE (1 << 1)
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#define DWC_CFGH_PROTCTL(x) ((x) << 2)
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+#define DWC_CFGH_PROTCTL_DATA (0 << 2) /* data access - always set */
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+#define DWC_CFGH_PROTCTL_PRIV (1 << 2) /* privileged -> AHB HPROT[1] */
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+#define DWC_CFGH_PROTCTL_BUFFER (2 << 2) /* bufferable -> AHB HPROT[2] */
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+#define DWC_CFGH_PROTCTL_CACHE (4 << 2) /* cacheable -> AHB HPROT[3] */
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#define DWC_CFGH_DS_UPD_EN (1 << 5)
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#define DWC_CFGH_SS_UPD_EN (1 << 6)
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#define DWC_CFGH_SRC_PER(x) ((x) << 7)
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--- a/include/linux/platform_data/dma-dw.h
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+++ b/include/linux/platform_data/dma-dw.h
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@@ -49,6 +49,7 @@ struct dw_dma_slave {
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* @data_width: Maximum data width supported by hardware per AHB master
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* (in bytes, power of 2)
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* @multi_block: Multi block transfers supported by hardware per channel.
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+ * @protctl: Protection control signals setting per channel.
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*/
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struct dw_dma_platform_data {
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unsigned int nr_channels;
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@@ -65,6 +66,11 @@ struct dw_dma_platform_data {
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unsigned char nr_masters;
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unsigned char data_width[DW_DMA_MAX_NR_MASTERS];
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unsigned char multi_block[DW_DMA_MAX_NR_CHANNELS];
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+#define CHAN_PROTCTL_PRIVILEGED BIT(0)
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+#define CHAN_PROTCTL_BUFFERABLE BIT(1)
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+#define CHAN_PROTCTL_CACHEABLE BIT(2)
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+#define CHAN_PROTCTL_MASK GENMASK(2, 0)
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+ unsigned char protctl;
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};
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#endif /* _PLATFORM_DATA_DMA_DW_H */
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