From: marex@denx.de (Marek Vasut) Date: Thu, 4 Jun 2015 17:20:54 +0200 Subject: [PATCH 11/11] dt: Exynos: add Snow SPI NOR node. In-Reply-To: <556FB222.2070406@samsung.com> References: <3234c12c90eabbeeb6d33604a324231937e309ec.1433364398.git.hramrach@gmail.com> <556FB222.2070406@samsung.com> Message-ID: <201506041720.54666.marex@denx.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thursday, June 04, 2015 at 04:04:18 AM, Krzysztof Kozlowski wrote: > On 04.06.2015 06:26, Michal Suchanek wrote: > > The Snow has onboard SPI NOR flash which contains the bootloader. > > > > Add DT node for this flash chip. The flash is rated 133MHz but the pl330 > > controller can transfer only up to 128 bytes at this speed so use more > > conservative settings. Even at 40MHz pl330 can transfer at most 64k with > > the current driver. > > > > Signed-off-by: Michal Suchanek > > --- > > > > arch/arm/boot/dts/exynos5250-snow.dts | 12 ++++++++++++ > > 1 file changed, 12 insertions(+) > > > > diff --git a/arch/arm/boot/dts/exynos5250-snow.dts > > b/arch/arm/boot/dts/exynos5250-snow.dts index 1fa72cf..38e4cda 100644 > > --- a/arch/arm/boot/dts/exynos5250-snow.dts > > +++ b/arch/arm/boot/dts/exynos5250-snow.dts > > @@ -691,6 +691,18 @@ > > > > num-cs = <1>; > > cs-gpios = <&gpa2 5 0>; > > status = "okay"; > > > > + flash: m25p80 at 0 { > > The indentation looks odd. This should be at the same level as "status". > > > + #address-cells = <1>; > > + #size-cells = <1>; > > + compatible = "jedec,spi-nor"; > > + reg = <0>; > > + spi-max-frequency = <40000000>; > > So actually you wanted 133 MHz but as a workaround for DMA issue you use > 40 MHz, right? Could you add here a small TODO note in comment about it? I disagree. There is a problem, the problem should actually be analyzed and fixed, not just postponed with some TODO nonsense. Best regards, Marek Vasut