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authorChristian Lamparter <chunkeey@gmail.com>2018-07-16 22:56:34 +0200
committerMathias Kresin <dev@kresin.me>2018-07-19 18:54:40 +0200
commit8a0ad2660a027e88550a08268093b7e0c993b556 (patch)
tree5482ab0e892645609d90f1cc591b8408e351b47e
parenta297324a135a699eb872e37461fad34a09281122 (diff)
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apm821xx: fix sata access freezes
The original vendor's driver programmed the dma controller's AHB HPROT values to enable bufferable, privileged mode. This along with the "same priorty for both channels" fixes the freezes according to @takimata, @And.short, that have been reported on the forum by @ticerex. Furtheremore, @takimata reported that the patch also improved the performance of the HDDs considerably: |<https://forum.lede-project.org/t/wd-mybook-live-duo-two-disks/16195/55> |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. Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
-rw-r--r--target/linux/apm821xx/patches-4.14/302-dw-dma-hprot-fix-and-equal-priortiy.patch25
1 files changed, 25 insertions, 0 deletions
diff --git a/target/linux/apm821xx/patches-4.14/302-dw-dma-hprot-fix-and-equal-priortiy.patch b/target/linux/apm821xx/patches-4.14/302-dw-dma-hprot-fix-and-equal-priortiy.patch
new file mode 100644
index 0000000..c6e4331
--- /dev/null
+++ b/target/linux/apm821xx/patches-4.14/302-dw-dma-hprot-fix-and-equal-priortiy.patch
@@ -0,0 +1,25 @@
+--- a/drivers/dma/dw/core.c
++++ b/drivers/dma/dw/core.c
+@@ -167,6 +167,8 @@ static void dwc_initialize_chan_dw(struc
+ cfghi |= DWC_CFGH_DST_PER(dwc->dws.dst_id);
+ cfghi |= DWC_CFGH_SRC_PER(dwc->dws.src_id);
+
++ cfghi |= DWC_CFGH_PROTCTL(3); /* bufferable + privileged access */
++
+ /* Set polarity of handshake interface */
+ cfglo |= hs_polarity ? DWC_CFGL_HS_DST_POL | DWC_CFGL_HS_SRC_POL : 0;
+
+@@ -1293,11 +1295,8 @@ int dw_dma_probe(struct dw_dma_chip *chi
+ else
+ list_add(&dwc->chan.device_node, &dw->dma.channels);
+
+- /* 7 is highest priority & 0 is lowest. */
+- if (pdata->chan_priority == CHAN_PRIORITY_ASCENDING)
+- dwc->priority = pdata->nr_channels - i - 1;
+- else
+- dwc->priority = i;
++ /* set all channels to the same priority */
++ dwc->priority = pdata->nr_channels - 1;
+
+ dwc->ch_regs = &__dw_regs(dw)->CHAN[i];
+ spin_lock_init(&dwc->lock);