On Mon, Jul 27, 2020 at 09:18:31AM +0000, Peng Fan wrote: > > Subject: Re: [PATCH 00/10] remoteproc: imx_rproc: support iMX8M and early > > boot > > > > On Mon, Jul 27, 2020 at 06:44:32AM +0000, Peng Fan wrote: > > > Hi Oleksij, > > > > > > > Subject: Re: [PATCH 00/10] remoteproc: imx_rproc: support iMX8M and > > > > early boot > > > > > > > > Hi, > > > > > > > > On Fri, Jul 24, 2020 at 04:08:03PM +0800, Peng Fan wrote: > > > > > This patchset is to support i.MX8MQ/M coproc booted before linux. > > > > > Since i.MX8MQ/M was not supported, several patches are needed to > > > > > first support the platform, then support early boot case. > > > > > > > > > > I intended to included i.MX8QM/QXP, but that would introduce a > > > > > large patchset, so not included. But the clk/syscon optional patch > > > > > for i.MX8QM/QXP was still kept here to avoid rebase error. > > > > > > > > Thank you for your work. > > > > > > > > Can you please provide more information about big picture of this work. > > > > > > > > If I see it correctly, we have here support for i.MX8MM, which seems > > > > to be able to fully control Cortex M4 (enable CPU core, etc...). > > > > > > Yes. > > > > In this case, I would recommend to mainline the i.MX8MM part > > first/separately. > > Only the last patch is to support earlyboot, all others is imx8mm part. ok > > > > > > > > > > And other case, where remoteproc is running on application processor > > > > and can't or should not touch M4 (i.MX7ULP, i.MX8QM/QXP..). Since M4 > > > > provides some functionality, you are trying to reuse remoteproc > > > > framework to get resource table present in ELF header and to > > > > dynamically load things. For some reasons this header provides more > > > > information then needed, so you are changing the ELF parser in the kernel > > to workaround it. > > > > > > Not exactly. > > > > > > For i.MX8MM, we support two cases. M4 kicked by U-Boot, M4 kicked by > > Linux remoteproc. > > > For i.MX8QM/QXP, the typical usecase is M4 kicked by SCFW, but we will > > > also add M4 kicked by Linux remoteproc. > > > For i.MX7ULP, I would only support M4 dual boot case, M4 control > > everything. > > > > From current state of discussion, i'm not sure what role plays remoteproc in > > the scenario where M4 is started before linux. Especially if we are not using > > resource table. > > We are using resource table from an address, not in elf file. > This is the new feature in Linux-next to support coproc booted early. > > > > > > The reason the change the elf parser is that when M4 elf is loaded by > > > Linux remoteproc, It use memset to clear area. > > > > The use of memset, depends on ELF format. Fix/change the linker script on > > your firmware and memset will be never called. > > > > > However we use ioremap, memset on ARM64 will report crash to device > > > nGnRE memory. And we could not use ioremap_wc to TCM area, since it > > > could have data correctly written into TCM. > > > > I have strong feeling, that we are talking about badly or not properly > > formatted ELF binary. I would prefer to double check it, before we will apply > > fixes on wrong place. > > > > > Maintainer not wanna to drop memset in common code, and TI guys > > > suggest add i.MX specific elf stuff. So I add elf handler in i.MX code. > > > > I think, removing memset may damage current users of imx_rproc driver. > > Since, like I said: the use of memset depends on ELF format. > > In my elf file, the last PT_LOAD contains data/bss/heap/stack. I'll check > with our MCU guys, we only need the specific data loaded. > > Elf file type is EXEC (Executable file) > Entry point 0x1ffe0355 > There are 3 program headers, starting at offset 52 > > Program Headers: > Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align > LOAD 0x010000 0x1ffe0000 0x1ffe0000 0x00240 0x00240 R 0x10000 > LOAD 0x010240 0x1ffe0240 0x1ffe0240 0x03e90 0x03e90 RWE 0x10000 > LOAD 0x020000 0x20000000 0x1ffe40d0 0x00068 0x0ad00 RW 0x10000 > > Section to Segment mapping: > Segment Sections... > 00 .interrupts > 01 .resource_table .text .ARM .init_array .fini_array > 02 .data .bss .heap .stack Here is an example of formatting ELF for remoteproc: https://git.pengutronix.de/cgit/ore/OSELAS.BSP-Pengutronix-DualKit/tree/local_src/remoteproc-elf/linker.ld https://git.pengutronix.de/cgit/ore/OSELAS.BSP-Pengutronix-DualKit/tree/local_src/remoteproc-elf/imx7m4.S In this example I pack linux in to remoteproc elf image and start linux on imx7d-m4 part. Will be interesting if you can do the same on imx8* SoCs ;) Regards, Oleksij -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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