| Message ID | 20200408173210.3904236-2-t.schramm@manjaro.org |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
| Series | Increase SPI speed on Mikrotik rbm11g and rbm33g | expand |
Hi! On Thu, Apr 9, 2020 at 1:32 AM Tobias Schramm <t.schramm@manjaro.org> wrote: > > Previously the dts were using a value determined by empirical testing, > because of a spi driver/clock bug. The bug was fixed quite some time > ago. 33 MHz is the default clock frequency used by RouterBOOT and thus > safe. > > Signed-off-by: Tobias Schramm <t.schramm@manjaro.org> > --- > target/linux/ramips/dts/mt7621_mikrotik_rbm11g.dts | 4 ++-- > target/linux/ramips/dts/mt7621_mikrotik_rbm33g.dts | 7 ++++--- > 2 files changed, 6 insertions(+), 5 deletions(-) > > diff --git a/target/linux/ramips/dts/mt7621_mikrotik_rbm11g.dts b/target/linux/ramips/dts/mt7621_mikrotik_rbm11g.dts > index aae899c9a6..b0a31602e3 100644 > --- a/target/linux/ramips/dts/mt7621_mikrotik_rbm11g.dts > +++ b/target/linux/ramips/dts/mt7621_mikrotik_rbm11g.dts > @@ -83,8 +83,8 @@ > w25q128@0 { > compatible = "jedec,spi-nor"; > reg = <0>; > - // XXX empiric value to obtain actual 10MHz SCK at the chip > - spi-max-frequency = <3125000>; > + m25p,fast-read; > + spi-max-frequency = <33000000>; m25p,fast-read isn't needed until spi frequency is higher than 50MHz and it affects performance a bit. It can be removed here and below.
Hi, >> @@ -83,8 +83,8 @@ >> w25q128@0 { >> compatible = "jedec,spi-nor"; >> reg = <0>; >> - // XXX empiric value to obtain actual 10MHz SCK at the chip >> - spi-max-frequency = <3125000>; >> + m25p,fast-read; >> + spi-max-frequency = <33000000>; > > m25p,fast-read isn't needed until spi frequency is higher than 50MHz > and it affects performance a bit. > It can be removed here and below. > Ah, snap. Something in the back of my mind told me m25p,fast-read was required from 25 MHz up. I'll send a v2 with it removed Thanks, Tobias
diff --git a/target/linux/ramips/dts/mt7621_mikrotik_rbm11g.dts b/target/linux/ramips/dts/mt7621_mikrotik_rbm11g.dts index aae899c9a6..b0a31602e3 100644 --- a/target/linux/ramips/dts/mt7621_mikrotik_rbm11g.dts +++ b/target/linux/ramips/dts/mt7621_mikrotik_rbm11g.dts @@ -83,8 +83,8 @@ w25q128@0 { compatible = "jedec,spi-nor"; reg = <0>; - // XXX empiric value to obtain actual 10MHz SCK at the chip - spi-max-frequency = <3125000>; + m25p,fast-read; + spi-max-frequency = <33000000>; partitions { compatible = "fixed-partitions"; diff --git a/target/linux/ramips/dts/mt7621_mikrotik_rbm33g.dts b/target/linux/ramips/dts/mt7621_mikrotik_rbm33g.dts index f7889bd68a..84bdaf06f1 100644 --- a/target/linux/ramips/dts/mt7621_mikrotik_rbm33g.dts +++ b/target/linux/ramips/dts/mt7621_mikrotik_rbm33g.dts @@ -93,7 +93,8 @@ w25q40@0 { compatible = "jedec,spi-nor"; reg = <0>; - spi-max-frequency = <3125000>; + m25p,fast-read; + spi-max-frequency = <33000000>; partitions { compatible = "fixed-partitions"; @@ -143,8 +144,8 @@ w25q128@1 { compatible = "jedec,spi-nor"; reg = <1>; - // XXX empiric value to obtain actual 10MHz SCK at the chip - spi-max-frequency = <3125000>; + m25p,fast-read; + spi-max-frequency = <33000000>; partitions { compatible = "fixed-partitions";
Previously the dts were using a value determined by empirical testing, because of a spi driver/clock bug. The bug was fixed quite some time ago. 33 MHz is the default clock frequency used by RouterBOOT and thus safe. Signed-off-by: Tobias Schramm <t.schramm@manjaro.org> --- target/linux/ramips/dts/mt7621_mikrotik_rbm11g.dts | 4 ++-- target/linux/ramips/dts/mt7621_mikrotik_rbm33g.dts | 7 ++++--- 2 files changed, 6 insertions(+), 5 deletions(-)