40 lines
1.8 KiB
Plaintext
40 lines
1.8 KiB
Plaintext
# 64 byte NVMe, Read command (a NVM command) that is suitable for:
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# sg_raw --cmdfile=<this_file_name> --nvm --request=2048 <nvme_device>
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#
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# The address field (at byte offset 24, 8 bytes and little endian) gives
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# special meaning to the highest address pointers:
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# ffffffff fffffffe use address of data-in buffer
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# ffffffff fffffffd use address of data-out buffer
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#
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# The data length field (at byte offset 36, 4 bytes and little endian)
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# gives special meaning to the highest block counts:
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# fffffffe use byte length of data-in buffer
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# fffffffd use byte length of data-out buffer
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#
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# 512 byte logical block size is assumed. Read 4 blocks hence 2048 bytes.
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# The first LBA read is 0x12345 and the namespace is 1. If successful
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# the four blocks will be read into the data-in buffer. Submission queue
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# 0 is used (the same queue that Admin commands use). The NVM opcode for
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# the Read command is 0x2 and appears in the first command byte.
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02 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00
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00 00 00 00 00 00 00 00 fe ff ff ff ff ff ff ff
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00 00 00 00 fe ff ff ff 45 23 01 00 00 00 00 00
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03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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# Notice NVMe uses its quirky "0's based" number of blocks so
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# 03 appears at byte offset 48 to mean "read 4 blocks".
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#
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# A typical invocation in Linux and FreeBSD would look like this:
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# sg_raw --cmdfile=nvme_read_ctl.hex --nvm -r 2048
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# --outfile=t.bin /dev/nvme0n1
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# In FreeBSD the device name would be /dev/nvme0ns1
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#
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# Notice the '--nvm' option which is needed to distinguish a NVM
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# command from an Admin command as Admin commands are the default
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# in this utility.
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#
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# This utility (and most others in the package) aligns data-in and
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# data-out buffers to the beginning of pages which are 4096 bytes
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# long at a minimum. This is the way NVMe likes things as well.
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