[PATCH 0/6] Expose RPi4'd bootloader configuration
Soon to be released versions of RPi4's firmware will take of care passing their bootloader's configuration to the OS by copying it into memory and creating a reserved memory node in the board's DT. In order to make use of this information, this series introduces a new generic nvmem driver that maps reserved-memory nodes into nvmem devices. An alternative approach, less nice IMO, would be to create a platform-specific 'soc' driver. Regards, Nicolas --- Nicolas Saenz Julienne (6): dt-bindings: nvmem: Add bindings for rmem driver nvmem: Add driver to expose reserved memory as nvmem ARM: dts: bcm2711: Add reserved memory template to hold firmware configuration ARM: dts: bcm2711: Expose boot-loader configuration arm64: defconfig: Enable nvmem's rmem driver ARM: multi_v7_defconfig: Enable nvmem's rmem driver .../devicetree/bindings/nvmem/rmem.yaml | 35 +++ arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 25 + arch/arm/configs/multi_v7_defconfig | 1 + arch/arm64/configs/defconfig | 1 + drivers/nvmem/Kconfig | 8 ++ drivers/nvmem/Makefile| 2 + drivers/nvmem/rmem.c | 92 +++ 7 files changed, 164 insertions(+) create mode 100644 Documentation/devicetree/bindings/nvmem/rmem.yaml create mode 100644 drivers/nvmem/rmem.c -- 2.29.2
Re: [PATCH 0/6] Expose RPi4'd bootloader configuration
On Tue, 2020-12-15 at 16:56 +0100, Nicolas Saenz Julienne wrote: > Soon to be released versions of RPi4's firmware will take of care > passing their bootloader's configuration to the OS by copying it into > memory and creating a reserved memory node in the board's DT. In order > to make use of this information, this series introduces a new generic > nvmem driver that maps reserved-memory nodes into nvmem devices. > > An alternative approach, less nice IMO, would be to create a > platform-specific 'soc' driver. > > Regards, > Nicolas There's a typo in the Subject, it should look like this: 'Expose RPi4's bootloader configuration' Regards, Nicolas signature.asc Description: This is a digitally signed message part
Re: [PATCH 0/6] Expose RPi4'd bootloader configuration
On Tue, Dec 15, 2020 at 04:56:20PM +0100, Nicolas Saenz Julienne wrote: > Soon to be released versions of RPi4's firmware will take of care > passing their bootloader's configuration to the OS by copying it into > memory and creating a reserved memory node in the board's DT. In order > to make use of this information, this series introduces a new generic > nvmem driver that maps reserved-memory nodes into nvmem devices. > > An alternative approach, less nice IMO, would be to create a > platform-specific 'soc' driver. What kind of information is this and how would the kernel use it? -- Catalin
Re: [PATCH 0/6] Expose RPi4'd bootloader configuration
Hi Catalin, On Tue, 2020-12-15 at 18:44 +, Catalin Marinas wrote: > On Tue, Dec 15, 2020 at 04:56:20PM +0100, Nicolas Saenz Julienne wrote: > > Soon to be released versions of RPi4's firmware will take of care > > passing their bootloader's configuration to the OS by copying it into > > memory and creating a reserved memory node in the board's DT. In order > > to make use of this information, this series introduces a new generic > > nvmem driver that maps reserved-memory nodes into nvmem devices. > > > > An alternative approach, less nice IMO, would be to create a > > platform-specific 'soc' driver. > > What kind of information is this and how would the kernel use it? Sorry, I wasn't clear enough, the ultimate goal is to use this information from user-space, through nvmem's sysfs interface. The kernel itself has no use for it. Regards, Nicolas signature.asc Description: This is a digitally signed message part
Re: [PATCH 0/6] Expose RPi4'd bootloader configuration
On Tue, Dec 15, 2020 at 1:01 PM Nicolas Saenz Julienne wrote: > > Hi Catalin, > > On Tue, 2020-12-15 at 18:44 +, Catalin Marinas wrote: > > On Tue, Dec 15, 2020 at 04:56:20PM +0100, Nicolas Saenz Julienne wrote: > > > Soon to be released versions of RPi4's firmware will take of care > > > passing their bootloader's configuration to the OS by copying it into > > > memory and creating a reserved memory node in the board's DT. In order > > > to make use of this information, this series introduces a new generic > > > nvmem driver that maps reserved-memory nodes into nvmem devices. > > > > > > An alternative approach, less nice IMO, would be to create a > > > platform-specific 'soc' driver. > > > > What kind of information is this and how would the kernel use it? > > Sorry, I wasn't clear enough, the ultimate goal is to use this information > from > user-space, through nvmem's sysfs interface. The kernel itself has no use for > it. That still leaves the first question. Rob
Re: [PATCH 0/6] Expose RPi4'd bootloader configuration
Hi Rob, thanks for having a look at this. On Tue, 2020-12-15 at 13:54 -0600, Rob Herring wrote: > On Tue, Dec 15, 2020 at 1:01 PM Nicolas Saenz Julienne > wrote: > > > > Hi Catalin, > > > > On Tue, 2020-12-15 at 18:44 +, Catalin Marinas wrote: > > > On Tue, Dec 15, 2020 at 04:56:20PM +0100, Nicolas Saenz Julienne wrote: > > > > Soon to be released versions of RPi4's firmware will take of care > > > > passing their bootloader's configuration to the OS by copying it into > > > > memory and creating a reserved memory node in the board's DT. In order > > > > to make use of this information, this series introduces a new generic > > > > nvmem driver that maps reserved-memory nodes into nvmem devices. > > > > > > > > An alternative approach, less nice IMO, would be to create a > > > > platform-specific 'soc' driver. > > > > > > What kind of information is this and how would the kernel use it? > > > > Sorry, I wasn't clear enough, the ultimate goal is to use this information > > from > > user-space, through nvmem's sysfs interface. The kernel itself has no use > > for > > it. > > That still leaves the first question. It's the bootloader configuration, stuff like boot order, TFTP IP, etc... See more here: https://www.raspberrypi.org/documentation/hardware/raspberrypi/bcm2711_bootloader_config.md I'll add a new paragraph explaining all this on next version's cover letter. Regards, Nicolas signature.asc Description: This is a digitally signed message part
