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nand_testing.md

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Nand testing

Warning: Most of these tests are destructive in nature.

Accessing the desired device

In order to test a particular device, that device must not be in use by the rest of the system. There are two ways to make that happen:

  • Prevent other drivers from binding to the device. This may involve building the system with modified binding rules for the driver that normally binds to the desired device, or passing kernel command line arguments to disable that driver.

  • Unbind devices that are bound to the desired device.

For example, in order to use a test tool against the core nand driver, nandpart devices may be removed like so:

$ unbind /dev/sys/platform/05:00:f/aml-raw_nand/nand/fvm

Warning: Before removing a particular device, remove its descendants. By extension, file systems must be unmounted before a block device is removed. Note that this requirement is likely to render a running system unusable, as the backing for the OS may be going away. Netboot may be the only viable option.

Note that all other devices created by nandpart must also be removed. Use driver dump to inspect the device tree.

Protocol testing

nand-test is an integration test that performs basic tests of nand protocol drivers.

For example, this command will test an existing ram-nand device making sure the test does not modify anything outside blocks [100, 109]:

$ /boot/test/sys/nand-test --device /dev/sys/platform/00:00:2e/nand-ctl/ram-nand-0 --first-block 100 --num-blocks 10

Correctness testing

nand-util is a troubleshooting tool that can perform a simple read-reliability test.

$ nand-util --device /dev/sys/platform/00:00:2e/nand-ctl/ram-nand-0 --check

Inspection / manipulation

$ nand-util --device /dev/sys/platform/05:00:f/aml-raw_nand/nand --info
$ nand-util --device /dev/sys/platform/05:00:f/aml-raw_nand/nand/fvm --read --block 1 --page 2

Grab an image

nand-util can also be used to grab an image of the nand contents:

Note: If a file system is already mounted, unbind will fail, and forcing it to work is likely to render the system unusable. Remember to netboot or use Zedboot as needed.

$ unbind /dev/sys/platform/05:00:f/aml-raw_nand/nand/fvm/ftl/block
$ unbind /dev/sys/platform/05:00:f/aml-raw_nand/nand/fvm/ftl
$ nand-util --device /dev/sys/platform/05:00:f/aml-raw_nand/nand/fvm --save --file /tmp/image

Transfer the image file to the host:

$ out/default/host-tools/netcp :/tmp/image /tmp/saved_image_file

Replay

A saved nand image can be loaded on top of a ram-nand device using nand-loader.

First, transfer the image to a device running Zircon. For example, on the host:

echo /nand.dmp=/tmp/saved_image_file > /tmp/manifest.txt
out/default/host-tools/minfs /tmp/image.dsk create --manifest /tmp/manifest.txt
fx set bringup.x64
fx build
fx qemu -k -- -hda /tmp/image.dsk

Then, inside zircon:

$ mkdir data/a
$ mount /dev/class/block/000 data/a
$ nand-loader data/a/nand.dmp