mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-18 10:48:51 +00:00
15c6935b0c
This patch contains UDM-design.txt, which is document containing general description of the driver model. The remaining files contains descriptions of conversion process of particular subsystems. Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
48 lines
1.6 KiB
Text
48 lines
1.6 KiB
Text
The U-Boot Driver Model Project
|
|
===============================
|
|
TPM system analysis
|
|
===================
|
|
Marek Vasut <marek.vasut@gmail.com>
|
|
2012-02-23
|
|
|
|
I) Overview
|
|
-----------
|
|
|
|
There is currently only one TPM chip driver available and therefore the API
|
|
controlling it is very much based on this. The API is very simple:
|
|
|
|
int tis_open(void);
|
|
int tis_close(void);
|
|
int tis_sendrecv(const u8 *sendbuf, size_t send_size,
|
|
u8 *recvbuf, size_t *recv_len);
|
|
|
|
The command operating the TPM chip only provides operations to send and receive
|
|
bytes from the chip.
|
|
|
|
II) Approach
|
|
------------
|
|
|
|
The API can't be generalised too much considering there's only one TPM chip
|
|
supported. But it's a good idea to split the tis_sendrecv() function in two
|
|
functions. Therefore the new API will use register the TPM chip by calling:
|
|
|
|
tpm_device_register(struct instance *i, const struct tpm_ops *ops);
|
|
|
|
And the struct tpm_ops will contain the following members:
|
|
|
|
struct tpm_ops {
|
|
int (*tpm_open)(struct instance *i);
|
|
int (*tpm_close)(struct instance *i);
|
|
int (*tpm_send)(const uint8_t *buf, const size_t size);
|
|
int (*tpm_recv)(uint8_t *buf, size_t *size);
|
|
};
|
|
|
|
The behaviour of "tpm_open()" and "tpm_close()" will basically copy the
|
|
behaviour of "tis_open()" and "tis_close()". The "tpm_send()" will be based on
|
|
the "tis_senddata()" and "tis_recv()" will be based on "tis_readresponse()".
|
|
|
|
III) Analysis of in-tree drivers
|
|
--------------------------------
|
|
|
|
There is only one in-tree driver present, the "drivers/tpm/generic_lpc_tpm.c",
|
|
which will be simply converted as outlined in previous chapter.
|