Re: [edk2-platform][PATCH v2 1/2] Platforms/RaspberryPi: Add RPi4 settings to Readme

["Pete Batard" <pete@akeo.ie>]

On 2020.06.15 22:43, Samer El-Haj-Mahmoud wrote:
> Add a section to the the RPi4 Readme for 'Configuration Settings', with
> instructions on scripting from the UEFI Shell.
> 
> Cc: Leif Lindholm <leif@nuviainc.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
> Cc: Pete Batard <pete@akeo.ie>
> Cc: Andrei Warkentin <awarkentin@vmware.com>
> Signed-off-by: Samer El-Haj-Mahmoud <samer.el-haj-mahmoud@arm.com>
> ---
>   Platform/RaspberryPi/RPi4/Readme.md | 74 +++++++++++++++++++-
>   1 file changed, 73 insertions(+), 1 deletion(-)
> 
> diff --git a/Platform/RaspberryPi/RPi4/Readme.md b/Platform/RaspberryPi/RPi4/Readme.md
> index 03eb6c391aca..98388e3caba1 100644
> --- a/Platform/RaspberryPi/RPi4/Readme.md
> +++ b/Platform/RaspberryPi/RPi4/Readme.md
> @@ -143,4 +143,76 @@ all functionality may be available.
>   
>   - Network booting via onboard NIC.
>   - SPCR hardcodes type to PL011, and thus will not expose correct
> -  (miniUART) UART if DT overlays to switch UART are used on Pi 4B.
> \ No newline at end of file
> +  (miniUART) UART if DT overlays to switch UART are used on Pi 4B.
> +
> +# Configuration Settings
> +The Raspberry Pi UEFI configuration settings can be viewed and changed using both the UI configuration menu (under `Device Manager` -> `Raspberry Pi Configuration`), as well as the UEFI Shell. To configure using the UEFI Shell, use `setvar` command to read/write the UEFI variables with GUID = `CD7CC258-31DB-22E6-9F22-63B0B8EED6B5`.
> +
> +The syntax to read a setting is:
> +```
> +setvar <NAME> -guid CD7CC258-31DB-22E6-9F22-63B0B8EED6B5
> +```
> +
> +The syntax to write a setting is:
> +```
> +setvar <NAME> -guid CD7CC258-31DB-22E6-9F22-63B0B8EED6B5 -bs -rt -nv =<VALUE>
> +```
> +
> +For string-type settings (e.g. Asset Tag), the syntax to write is:
> +```
> +setvar <NAME> -guid CD7CC258-31DB-22E6-9F22-63B0B8EED6B5 -bs -rt -nv =L"<VALUE>" =0x0000
> +```
> +
> +UEFI Setting                 |    NAME               |  VALUE
> +-----------------------------|-----------------------|-----------------------------
> +**CPU Configuration**        |
> +CPU Clock                    | `CpuClock` | Low = `0x00000000`<br> Default = `0x00000001` (default)<br> Max = `0x00000002`<br> Custom = `0x00000003`
> +CPU Clock Rate (MHz)         | `CustomCpuClock` | Hex numeric value, 4-bytes<br> (e.g. `0x000005DC` for 1500 MHz)
> +**Display Configuration**    |
> +Virtual 640x480              | `DisplayEnableScaledVModes` | Checked = Bit 0 set (i.e.  `<DisplayEnableScaledVModes> \| 0x01`)
> +Virtual 800x600              | `DisplayEnableScaledVModes` | Checked = Bit 1 set (i.e.  `<DisplayEnableScaledVModes> \| 0x02`)
> +Virtual 1024x768             | `DisplayEnableScaledVModes` | Checked = Bit 2 set (i.e.  `<DisplayEnableScaledVModes> \| 0x04`)
> +Virtual 720p                 | `DisplayEnableScaledVModes` | Checked = Bit 3 set (i.e.  `<DisplayEnableScaledVModes> \| 0x08`)
> +Virtual 1080p                | `DisplayEnableScaledVModes` | Checked = Bit 4 set (i.e.  `<DisplayEnableScaledVModes> \| 0x10`)
> +Native resolution            | `DisplayEnableScaledVModes` | Checked = Bit 5 set (i.e.  `<DisplayEnableScaledVModes> \| 0x20`) (default)
> +Screenshot support           | `DisplayEnableSShot` | Control-Alt-F12 = `0x00000001` (default)<br> Not Enabled = `0x00000000`
> +**Advanced Configuration**   |
> +Limit RAM to 3 GB            | `RamLimitTo3GB` | Disable = `0x00000000` <br> Enabled= `0x00000001` (default)
> +System Table Selection       | `SystemTableMode`| ACPI = `0x00000000` (default)<br> ACPI + Devicetree = `0x00000001` <br> Devicetree = `0x00000002`
> +Asset Tag                    | `AssetTag` | String, 32 characters or less (e.g. `L"ABCD123"`)<br> (default `L""`)
> +**SD/MMC Configuration**     |
> +uSD/eMMC Routing             | `SdIsArasan` | Arasan SDHC = `0x00000001` (default) <br> eMMC2 SDHCI = `0x00000000`
> +Multi-Block Support          | `MmcDisableMulti` | Multi-block transfers = `0x00000000` (default)<br> Single block transfers = `0x00000001`
> +uSD Max Bus Width            | `MmcForce1Bit` | 4-bit Mode = `0x00000000`  (default)<br> 1-bit Mode = `0x00000001`
> +uSD Force Default Speed      | `MmcForceDefaultSpeed` | Allow High Speed = `0x00000000` (default)<br> Force Default Speed = `0x00000001`
> +SD Default Speed (MHz)       | `MmcSdDefaultSpeedMHz` | Hex numeric value, 4-bytes (e.g. `0x00000019` for 25 MHz)<br>(default 25)
> +SD High Speed (MHz)          | `MmcSdHighSpeedMHz` | Hex numeric value, 4-bytes (e.g. `0x00000032` for 50 MHz)<br>(default 50)
> +**Debugging Configuration**  |
> +JTAG Routing                 | `DebugEnableJTAG` | Enable JTAG via GPIO = `0x00000001`<br> Disable JTAG= `0x00000000` (default)
> +
> +**Examples:**
> +
> +- To read the 'System Table Selection' setting :
> +```
> +setvar SystemTableMode -guid CD7CC258-31DB-22E6-9F22-63B0B8EED6B5
> +```
> +
> +- To change the 'System Table Selection' setting to 'Devicetree' :
> +```
> +setvar SystemTableMode -guid CD7CC258-31DB-22E6-9F22-63B0B8EED6B5 -bs -rt -nv =0x00000002
> +```
> +
> +- To read the 'Limit RAM to 3 GB' setting:
> +```
> +setvar RamLimitTo3GB -guid CD7CC258-31DB-22E6-9F22-63B0B8EED6B5
> +```
> +
> +- To change the 'Limit RAM to 3 GB' setting to 'Disabled':
> +```
> +setvar RamLimitTo3GB -guid CD7CC258-31DB-22E6-9F22-63B0B8EED6B5 -bs -rt -nv =0x00000000
> +```
> +
> +- To change the Asset Tag to the string "ASSET-TAG-123" :
> +```
> +setvar AssetTag -guid CD7CC258-31DB-22E6-9F22-63B0B8EED6B5 -bs -rt -nv =L"ASSET-TAG-123" =0x0000
> +```
> 

Reviewed-by: Pete Batard <pete@akeo.ie>