Merge pull request 'added generic SPI docs' (#38) from shmalebx9/lbwww:dev into master

Reviewed-on: https://codeberg.org/libreboot/lbwww/pulls/38

site/docs/install/spi.md

@@ -18,6 +18,7 @@ libreboot currently documents how to use these SPI programmers:
 
 * Raspberry Pi (RPi)
 * BeagleBone Black (BBB)
+* Libre Computer 'Le Potato'
 
 Many other SPI programmers exist. More of them will be documented on this page,
 at a date in the future. You can otherwise figure it out on your own; certain
@@ -153,6 +154,14 @@ directly.
 Software configuration
 ======================
 
+General/Le potato
+-----------------
+
+The [generic guide](spi_generic.md) is intended to help those looking to use an
+SBC which is not listed in this guide.
+The guide will, however, use the libre computer 'Le Potato' as a reference board.
+If you have that board, you should refer to the [generic guide.](spi_generic.md)
+
 BeagleBone Black (BBB)
 ----------------------
 

site/docs/install/spi_generic.md

@@ -0,0 +1,103 @@
+---
+title: Generic SPI Flashing Guide
+x-toc-enable: true
+...
+
+There are a plethora of single board computers with which you can flash libreboot to a SOIC chip.
+Some users might be daunted by the price of a raspberry pi.
+This guide is intended to help users looking to use a programmer which is not listed in the [main guide.](spi.md)
+As an example, this guide will use the [libre computer 'le potato.'](https://libre.computer/products/aml-s905x-cc/)
+You should note however, that this guide is intended to demonstrate how to set up any SBC with SPI programming capabilities for flashing libreboot.
+
+If you are wondering about which SBC to buy, keep these things in mind:
+
++ The board *must* support SPI (look at the specs/pinout to find out if it does)
++ It is easier to use a board that supports raspbian/raspberry pi OS
++ Boards often require their own kernel patches which rarely get upstreamed
+
+All of this means that you should try to find a board that is *known* to support SPI on an OS for which there are available images.
+It is *not* enough to know that the board itself supports SPI.
+
+Selecting an Operating System
+=============================
+
+In theory, any linux based operating system will do.
+In practice, many distros are highly limited when it comes to single-board-computers.
+SBCs often require specialized kernel patches which are rarely upstreamed.
+Additionally, armhf boards (like the le potato) are not supported in most modern distros.
+
+In light of the above facts, it is a good general rule to use a distro aimed at supporting SBCs.
+[Armbian](https://www.armbian.com/) is one such distro you might use.
+Note that not all armbian images support SPI.
+If your SBC supports [Raspbian](https://www.raspberrypi.com/software/) then using it will make your work much easier.
+As a bonus, you may refer to the [main guide](spi.md) if the SBC you have supports raspbian, should you get confused with this guide.
+
+Connecting to your Programmer
+=============================
+
+Many SBC operating systems enable ssh by default.
+If the OS you chose does not enable ssh on first boot, try checking the distro documentation and looking for terms such as 'headless install.'
+
+You will need the IP address of your programmer to continue.
+Connecting via ethernet is generally easier than doing so with WiFi.
+Check your distro's docs if you wish to connect with WiFi only.
+To determine the IP address of your programmer, log in to your AP/Router web interface.
+If you're not sure the IP address of your AP, it is likely `192.168.1.1.`
+You can determine the correct IP address with `ip r` on a linux machine.
+You should see your programmer somewhere on the homepage, depending on your router firmware.
+This author recommends using [https://openwrt.org/](https://openwrt.org/) for your router firmware.
+
+SSH to your programmer using the default credentials as specified in your distro's docs.
+The IP address is the one determined in the earlier step.
+For example:
+
+`ssh root@192.168.0.167`
+
+Finding GPIO Pins
+=================
+
+If you have determined that a board supports SPI then the only step left is to
+determine the correct location of the SPI pins.
+The board will have the pinout in its documentation.
+The Le potato board has the same pinout as the raspberry pi so you can refer to the [main SPIC documentation.](spi.md#gpio-pins-on-raspberry-pi-rpi-40-pin)
+
+If your board is not raspberry pi compatible, refer to the [wiring table.](spi.html#soic8dip8wson8-wiring-diagram)
+Match each of the categories in the 'signal' column with those in the 'pin' column.
+Using this method, you can theoretically use any single board computer with SPI support.
+
+Enabling SPI
+============
+
+The modules needed and methods to enable SPI vary based on the SBC you choose.
+You should always make sure there is a well documented method for enabling SPI on your SBC before purchasing.
+In the case of the *le potato,* SPI is enabled by activating the correct overlays as such (raspbian):
+
+```
+sudo ldto enable spicc spicc-spidev
+sudo ldto merge spicc spicc-spidev
+```
+
+Using Flashrom
+==============
+
+Most linux distros will provide flashrom in their default repositories.
+You can also download flashrom in binary form with [libreboot utils.](https://libreboot.org/download.html#https)
+Here is an example using raspbian:
+
+```
+sudo apt update
+sudo apt install flashrom
+```
+
+Reading/writing from SPI works respectively as such:
+
+```
+sudo ./flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=32768 -r /path/to/read.bin
+sudo ./flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=32768 -w /path/to/libreboot.rom
+```
+
+Note that `spispeed` varies based on the board in question.
+A standard lower limit is *512.*
+For example, to read on a board with a lower SPI speed, you may try:
+
+	sudo ./flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=512 -r /path/to/read.bin