From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.visioncatalog.de ([217.6.246.34] helo=root.phytec.de) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cdbNt-0001Ao-CW for barebox@lists.infradead.org; Tue, 14 Feb 2017 11:35:03 +0000 References: <4bcf7de3-5ced-3575-9495-c1f4f20ce60c@phytec.de> <20170213192247.gjld5b33genwav2a@pengutronix.de> <6ff1f0fb-5847-e927-0602-a61c35a58e5b@phytec.de> <20170214104833.k5oubzucxb3o67rf@pengutronix.de> From: Wadim Egorov Message-ID: Date: Tue, 14 Feb 2017 12:34:37 +0100 MIME-Version: 1.0 In-Reply-To: <20170214104833.k5oubzucxb3o67rf@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 14.02.2017 11:48, Sascha Hauer wrote: > On Tue, Feb 14, 2017 at 10:54:49AM +0100, Wadim Egorov wrote: >> 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. > The ENTRY_FUNCTION macro is not prepared for returning to the caller. > > You'll have to replace it with something like: > > void __section(.text_head_entry_start_rk3288_phycore_som) > start_start_imx6q_sabrelite(uint32_t r0, uint32_t r1, uint32_t r2) > > This makes sure the link register is preserved and is jumped to at the > end of the function. > > You could also send me some hardware, I could provide some better help > then. I know this early bringup can be tricky ;) I will send you our hardware. After the redesign :) > > Sascha > _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox