From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cyrille Pitchen Subject: Re: [PATCH v2 5/6] ARM: at91: change compatibility string for sama5d3x gem Date: Thu, 24 Jul 2014 17:57:42 +0200 Message-ID: <53D12CF6.6070502@atmel.com> References: <20140724151529.GA26190@leverpostej> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "nicolas.ferre@atmel.com" , "davem@davemloft.net" , "linux-arm-kernel@lists.infradead.org" , "netdev@vger.kernel.org" , "soren.brinkmann@xilinx.com" , "linux-kernel@vger.kernel.org" To: Mark Rutland Return-path: In-Reply-To: <20140724151529.GA26190@leverpostej> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Le 24/07/2014 17:15, Mark Rutland a =E9crit : > On Thu, Jul 24, 2014 at 12:51:02PM +0100, Cyrille Pitchen wrote: >> this new compatibility string prevents macb/gem driver from using th= e >> scatter-gather and gso features on sama5d3x boards. >=20 > What will happen were the driver to attempt to use the features on th= is > board? >=20 > How will this affect existing DTBs? >=20 > Thanks, > Mark. > Hi Mark, patch 2 for then scatter-gather feature introducted a new compatible st= ring "atmel,sama5d3-gem". Its associated config has the MACB_CAPS_SG_DISABLE= D flag so the feature is not available indeed. patch 2 also set the very same flag for the config associated to the al= ready=20 existing strings "cdns,pc302-gem" and "cdns,gem". Then if you don't upd= ate=20 your device tree, the scatter-gather feature won't be enabled for gem a= nyway.=20 However SG feature will be enabled for the old macb. The main idea is to do the change in two steps to avoid indroducing bug= s. This series of patches is the first step. Later an additionnal patch may be=20 introduced to enable SG feature for gem on all platforms but sama5d3x. = This=20 should be done by removing the MACB_CAPS_SG_DISABLED flag from pc302gem= _config. Till then you don't need to update your device tree. =46or now, the SG feature is known to be broken on sama5d3x and there i= s work in=20 progress with Cadence support to fix this issue. It seems to be specifi= c to=20 sama5d3x gem. SG feature was successfully tested on sama5d3x macb and a= lso on=20 sama5d4 gem. Regards, Cyrille >> >> Signed-off-by: Cyrille Pitchen >> --- >> arch/arm/boot/dts/sama5d3_gmac.dtsi | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/arm/boot/dts/sama5d3_gmac.dtsi b/arch/arm/boot/dts= /sama5d3_gmac.dtsi >> index a6cb050..de5ed59 100644 >> --- a/arch/arm/boot/dts/sama5d3_gmac.dtsi >> +++ b/arch/arm/boot/dts/sama5d3_gmac.dtsi >> @@ -74,7 +74,7 @@ >> }; >> =20 >> macb0: ethernet@f0028000 { >> - compatible =3D "cdns,pc302-gem", "cdns,gem"; >> + compatible =3D "atmel,sama5d3-gem"; >> reg =3D <0xf0028000 0x100>; >> interrupts =3D <34 IRQ_TYPE_LEVEL_HIGH 3>; >> pinctrl-names =3D "default"; >> --=20 >> 1.8.2.2 >> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >>