Re: [PATCH 1/1] arm64: dts: qcom: msm8994: Reserve gpio ranges

From: Petr Vorel <petr.vorel@gmail.com>
To: Konrad Dybcio <konradybcio@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	MSM <linux-arm-msm@vger.kernel.org>,
	Andy Gross <agross@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Ricardo Ribalda <ribalda@kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>
Subject: Re: [PATCH 1/1] arm64: dts: qcom: msm8994: Reserve gpio ranges
Date: Fri, 9 Apr 2021 05:19:30 +0200	[thread overview]
Message-ID: <YG/HwrzRcm7bwgFe@pevik> (raw)
In-Reply-To: <ea376d51-cd6c-0028-9602-d007c2bba71e@gmail.com>

Hi Konrad,
> Hi,

> to clear up some confusion:


> On Qualcomm boards GPIOs that are used for "secure" (duh) peripherals,
> like a fingerprint scanner, are not allowed to be controlled from Linux (the "non-secure world").
> Trying to do so causes an immediate reboot due to "attempting to violate the security".
Thanks for an explanation.

> The GPIOs seem to all be iterated over on boot, except for the ones specified in "gpio-reserved-ranges".
> As a result, if such "secure" GPIOs are not declared in the DT, the board essentially dies on TLMM (pinctrl) probe
> (which happens veeeery early - so that all other peripherals can set the pins as they see fit)
> and that's very unpleasant to debug. Without this patch, Petr's device will simply not boot.
Exactly.

> So, why did it work before!?


> Well, either the GPIOs weren't iterated over, or the TLMM (pinctrl) driver wasn't in place back then.
I suppose GPIOs not being iterated over is the case for first fix (i.e. fixing
3edfb7bd76bd "gpiolib: Show correct direction from the beginning").

> As for the initrd crash.. perhaps you have an Android initrd which dies as soon as it doesn't detect SELINUX and a couple of other options.. You might want to try postmarketOS's one, or any other Linux distro's armv7/aarch64 initrd. To replace it, simply use abootimg like so:
No, that's postmarketOS initrd which dies

before a99163e9e708d5d773b7de6da952fcddc341f977:
[   17.421112] ALSA device list:
[   17.426233]   No soundcard?[   17.436163] Freeing unused kernel memory: 5760K
[   17.436462] Run /init as init process
[   17.439499]   with arguments:
[   17.443330]     /init
[   17.446277]     PMOS_NO_OUTPUT_REDIRECT
[   17.448535]   with environment:
[   17.452172]     HOME=/
[   17.455303]     TERM=linux
### postmarketOS initramfs ###
Configuring kernel firmware image search path
/init: line 56: can't create /proc/sys/kernel/hotplug: nonexistent directory
Trying to mount subpartitions for 10 seconds...

after a99163e9e708d5d773b7de6da952fcddc341f977:
[   17.383267] calling  regulator_init_complete+0x0/0x4c @ 1
[   17.390129] initcall regulator_init_complete+0x0/0x4c returned 0 after 6 usecs
[   17.395682] calling  of_platform_sync_state_init+0x0/0x18 @ 1
[   17.402800] initcall of_platform_sync_state_init+0x0/0x18 returned 0 after 3 usecs
[   17.408616] calling  alsa_sound_last_init+0x0/0x88 @ 1
[   17.416077] ALSA device list:
[   17.421198]   No soundcardű[   17.431360] Freeing unused kernel memory: 5824K
[   17.431633] Run /init as init process
[   17.434700]   with arguments:
[   17.438535]     /init
[   17.441477]     PMOS_NO_OUTPUT_REDIRECT
[   17.443737]   with environment:
[   17.447381]     HOME=/
[   17.450496]     TERM=linux
D -     15494 - pm_driver_init, Delta

> abootimg -u boot.img -r ramdisk.img


> If it says something something "too small", add


> -c "bootsize=30000000"


> to make the boot.img exactly 30 million bytes (or change it as you see fit).
abootimg is really ok, this is not the issue.

> Konrad

Kind regards,
Petr