From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.phycore.de ([217.6.246.34] helo=root.phytec.de) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cdZpJ-0005WI-O8 for barebox@lists.infradead.org; Tue, 14 Feb 2017 09:55:20 +0000 References: <4bcf7de3-5ced-3575-9495-c1f4f20ce60c@phytec.de> <20170213192247.gjld5b33genwav2a@pengutronix.de> From: Wadim Egorov Message-ID: <6ff1f0fb-5847-e927-0602-a61c35a58e5b@phytec.de> Date: Tue, 14 Feb 2017 10:54:49 +0100 MIME-Version: 1.0 In-Reply-To: <20170213192247.gjld5b33genwav2a@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: barebox PBL question To: Sascha Hauer Cc: "barebox@lists.infradead.org" On 13.02.2017 20:22, Sascha Hauer wrote: > On Mon, Feb 13, 2017 at 04:13:48PM +0100, Wadim Egorov wrote: >> Hi, >> >> I would like to add SPL support for the RK3288 SoC to barebox. But I am >> facing >> a few problems. >> >> The maximum size of the SPL image which the ROM code will read is 32KB. >> I was thinking to use the PBL feature for the SPL part. But using the >> the pbl code (with decompression) seems to be not a good idea, because >> it's size >> is already about 30K. I think this is an overhead. > In a test build here the pbl code is 6KiB. The rest is the devicetree > included in the binary (which I disabled in the test build). The dtb can > be compressed which should give you enough space even in 32KiB. OK, I think I checked the wrong file size. pblb is the bare binary file > >> But now I wonder how to generate two different images with a single build. >> A SPL image, which should not exceed 32K and a barebox. >> >> I have problems to fully understand the PBL mechanism. >> Why are the builds always adding the barebox.bin images to the PBL part? > The idea is to create an image that contains the PBL and attached to it > the compressed barebox image. If your ROM only allows a certain image > size then make sure the PBL is small enough and tell the ROM to only > load the PBL part of the image. Ideally the PBL then detects from where > the PBL is loaded (by reading back the bootsource the SoC provides) and > reads the rest of the image into SDRAM (or, for sake of simplicity, the > whole image inculding PBL again) ty for clarification > >> Here is an example, cat .zbarebox.cmd >> >> ld -EL -Map arch/arm/pbl/zbarebox.map --gc-sections -static -o >> arch/arm/pbl/zbarebox -e pbl_start -T arch/arm/pbl/zbarebox.lds >> --start-group common/built-in-pbl.o [...] arch/arm/pbl/piggy.shipped.o >> --end-group >> >> piggy.shipped.o is barebox.bin, which is added in piggy.shipped.S: >> >> .incbin "arch/arm/pbl/piggy.shipped" > You should use PBL_MULTI_IMAGES instead. In fact, the existing Rockchip > port already does this. > > I think your entry function should look something like: > > ENTRY_FUNCTION(start_rk3288_phycore_som, r0, r1, r2) > { > arm_cpu_lowlevel_init(); > > if (inside_sdram(get_pc())) > barebox_arm_entry(0x0, SZ_1G, fdt); > > rk3288_phycore_setup_sdram(); > > jump_back_to_rom(); > } > > I don't know how jump_back_to_rom() should be implemented. Do you have > to return from the entry function to the ROM or does the ROM provide some API > which can be used to chainload the rest of the image? No, there is no API in the ROM. In u-boot the spl will return to bootrom in board_init_f(), then bootrom loads u-boot binary. Regards, Wadim > > What you'll need additionally is a tool which encapsulates the image into > a SoC specific container suitable for the ROM. > > Sascha > _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox