On 2 April 2016 at 02:23, Gwendal Grignou <gwendal@xxxxxxxxxxxx> wrote: > On Thu, Jan 14, 2016 at 5:16 AM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: >> On 28 December 2015 at 15:12, Alex Lemberg <Alex.Lemberg@xxxxxxxxxxx> wrote: >>> Hi Ulf, >>> >>> We succeeded to run FFU via new mmc multi-command ioctl without any code modification, >>> but only by using Single Sector commands (CMD24). >>> >>> From running the FFU and from code review, we see two minor issues in this way of running FFU: >>> 1. There is no support for Multiple Block write commands (CMD25) in existing IOCTL implementation - >> >> That's right. But I guess we cope without the multiple block support!? >> >> Although, I wonder how hard it would be to add it... >> >>> seems like there is no polling for the card status on data transfer completion. >> >> We should fix that! >> >> In the rpmb case, we check the status so we can probably trigger that >> code to run for CMD24/25 as well. >> >>> (The kernel FFU implementation supports FFU using Multiple Block Write commands). >>> 2. As you probably remember, there are two ways to install the new FW in the end of FFU process - >>> In case MODE_OPERATION_CODES field is not supported by the device, the host sets to NORMAL state >> >> Before starting the update, you can find out which mode that is >> supported and take relevant actions, right? >> >>> and initiates a CMD0/HW_Reset/Power cycle to install the new firmware. >> >> Yes, but that's fragile - as discussed earlier. >> >> What we really need to do is to also remove the "card" device from the >> system, as otherwise we may have invalid data in its member variables >> and who knows what issues that can cause to upper levels. >> >>> This sequence cannot be done via multi-command ioctl, and requires manual reset of the device/platform. >> >> Yepp, it seems so at least for now. Perhaps we can think of a way to >> improve this? >> >>> (The kernel FFU implementation supports both FW install methods). >>> >>> For running FFU via new mmc multi-command ioctl, we have modified mmc-utils and add new functionality for FFU. >>> Please let us know if you want us to submit the patch for mmc-utils FFU functionality via multi-command ioctl. >> >> Yes please. Don't forget to send this to Chris as well! > I am arriving after the battle, but I have finally rebased the eMMC > FFU kernel ffu code to 4.x. It is based on what Avi and Alex have > written. > As stated earlier, the advantage over using MMC_MUTLI_CMD is we can > force a reset and rescan of the card without asking the user to reboot > their machine. No matter what, I think the problem is how you would *safely* deal with the reset. Especially in the case when the eMMC already has an mounted file system on it. Just doing something that *might* work, isn't good enough to me. > Also, by only sending a firmware name over the ioctl, we can use Kees' > work for firmware validation (https://lwn.net/Articles/605432/). The request_firmware() interface would indeed be good to use. Although unless we can figure out a way on how to safely deal with reset, we will have to live without request_firmware(). > To prevent downloading firmware from unknown source, we would reject > some commands (like SWITCH with FFU_MODE) in the kernel > MMC_IOC/MULTI_CMD ioctl handler. I don't follow, can you elaborate on this please. Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
