From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from na01-by2-obe.outbound.protection.outlook.com (mail-by2on0105.outbound.protection.outlook.com [207.46.100.105]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id DB56C1A0BB5 for ; Thu, 9 Oct 2014 03:30:41 +1100 (EST) Message-ID: <1412785827.13320.532.camel@snotra.buserror.net> Subject: Re: [PATCH v2 1/2] spi: fsl-spi: Fix parameter ram offset setup for CPM1 From: Scott Wood To: leroy christophe Date: Wed, 8 Oct 2014 11:30:27 -0500 In-Reply-To: <5435649F.5070908@c-s.fr> References: <20141003164916.DBD631AAFA2@localhost.localdomain> <1412368198.13320.434.camel@snotra.buserror.net> <542FE1C4.7000403@c-s.fr> <1412640953.13320.502.camel@snotra.buserror.net> <5435649F.5070908@c-s.fr> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Cc: Mark Brown , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 2014-10-08 at 18:21 +0200, leroy christophe wrote: > Le 07/10/2014 02:15, Scott Wood a écrit : > > On Sat, 2014-10-04 at 14:02 +0200, christophe leroy wrote: > >> What should it look like if that offset had to be in the device tree ? > > If the offset is not relocatable or discoverable, it should stay in the > > device tree. If you have an old chip you wouldn't have > > fsl,cpm1-spi-reloc and thus you'd still have "0x3d80 0x30" in reg. > This index is from the start of the dual port RAM. It is 0x2000 above > the start of the CPM area. > In the DTS, we have: > > soc@ff000000 { > compatible = "fsl,mpc885", "fsl,pq1-soc"; > #address-cells = <1>; > #size-cells = <1>; > device_type = "soc"; > ranges = <0x0 0xff000000 0x28000>; > bus-frequency = <0>; > clock-frequency = <0>; > > cpm@9c0 { > #address-cells = <1>; > #size-cells = <1>; > compatible = "fsl,mpc885-cpm", "fsl,cpm1"; > ranges; > reg = <0x9c0 0x40>; > brg-frequency = <0>; > interrupts = <0>; // cpm error interrupt > interrupt-parent = <&CPM_PIC>; > > muram@2000 { > #address-cells = <1>; > #size-cells = <1>; > ranges = <0x0 0x2000 0x2000>; > > data@0 { > compatible = "fsl,cpm-muram-data"; > reg = <0x0 0x1c00>; > }; > }; > > spi: spi@a80 { > #address-cells = <1>; > #size-cells = <0>; > cell-index = <0>; > compatible = "fsl,spi", "fsl,cpm1-spi"; > reg = <0xa80 0x30 0x3d80 0x30>; > interrupts = <5>; > interrupt-parent = <&CPM_PIC>; > mode = "cpu"; > > > The binding allows me to do an of_iomap() on the parameter RAM, hence to > get access to the relocation index which is inside it. > But if the relocation index is 0, I have to calculate it by myself > because the calling function expects it in return. > The binding is also supposed to tell that the muram is at 0xff002000. > But I don't know how I can get this info and use it to calculate the > index of my param RAM ? I need to calculate the index which is 1d80 > (0x3d80 - 0x2000) What binding are you talking about? There is no published binding for this yet. As for what the driver should do, it should do an of_iomap(), but what it does with the resulting memory depends on the compatible. For fsl,cpm1-spi, the result would be the parameter RAM for the device. For fsl,cpm1-spi-reloc and fsl,cpm2-spi, it would be the relocation register. The driver would either read the contents of the register, or write a different offset. My understanding is that the relocation register would only be zero on the chips where we'd use fsl,cpm1-spi, not fsl,cpm1-spi-reloc. -Scott