+ Jens Hi Stefano, On Tue, Mar 11, 2025 at 11:01:29AM +0100, Stefano Garzarella wrote: > This driver does not support interrupts, and receiving the response is > synchronous with sending the command. > > It used an internal buffer to cache the response when .send() is called, > and then return it when .recv() is called. > > Let's simplify the driver by implementing the new send_recv() op, so that > we can also remove the 4KB internal buffer used to cache the response. Looks like a nice cleanup to me but it needs to be tested. Jens, can you give this patch a try? > > Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx> > --- > Note: I don't know how to test this driver, so I just build it. > If someone can test it, or tell me how to do, it will be great! The fTPM is now maintained as part of OP-TEE project here [1]. The instructions to test it on Qemu can be found here [2] as part of CI pipeline. [1] https://github.com/OP-TEE/optee_ftpm [2] https://github.com/OP-TEE/optee_ftpm/blob/master/.github/workflows/ci.yml -Sumit > --- > drivers/char/tpm/tpm_ftpm_tee.h | 4 -- > drivers/char/tpm/tpm_ftpm_tee.c | 86 ++++++++------------------------- > 2 files changed, 21 insertions(+), 69 deletions(-) > > diff --git a/drivers/char/tpm/tpm_ftpm_tee.h b/drivers/char/tpm/tpm_ftpm_tee.h > index f98daa7bf68c..72b2f5c41274 100644 > --- a/drivers/char/tpm/tpm_ftpm_tee.h > +++ b/drivers/char/tpm/tpm_ftpm_tee.h > @@ -23,16 +23,12 @@ > * @chip: struct tpm_chip instance registered with tpm framework. > * @state: internal state > * @session: fTPM TA session identifier. > - * @resp_len: cached response buffer length. > - * @resp_buf: cached response buffer. > * @ctx: TEE context handler. > * @shm: Memory pool shared with fTPM TA in TEE. > */ > struct ftpm_tee_private { > struct tpm_chip *chip; > u32 session; > - size_t resp_len; > - u8 resp_buf[MAX_RESPONSE_SIZE]; > struct tee_context *ctx; > struct tee_shm *shm; > }; > diff --git a/drivers/char/tpm/tpm_ftpm_tee.c b/drivers/char/tpm/tpm_ftpm_tee.c > index 139556b21cc6..f0393d843780 100644 > --- a/drivers/char/tpm/tpm_ftpm_tee.c > +++ b/drivers/char/tpm/tpm_ftpm_tee.c > @@ -31,45 +31,19 @@ static const uuid_t ftpm_ta_uuid = > 0x82, 0xCB, 0x34, 0x3F, 0xB7, 0xF3, 0x78, 0x96); > > /** > - * ftpm_tee_tpm_op_recv() - retrieve fTPM response. > - * @chip: the tpm_chip description as specified in driver/char/tpm/tpm.h. > - * @buf: the buffer to store data. > - * @count: the number of bytes to read. > - * > - * Return: > - * In case of success the number of bytes received. > - * On failure, -errno. > - */ > -static int ftpm_tee_tpm_op_recv(struct tpm_chip *chip, u8 *buf, size_t count) > -{ > - struct ftpm_tee_private *pvt_data = dev_get_drvdata(chip->dev.parent); > - size_t len; > - > - len = pvt_data->resp_len; > - if (count < len) { > - dev_err(&chip->dev, > - "%s: Invalid size in recv: count=%zd, resp_len=%zd\n", > - __func__, count, len); > - return -EIO; > - } > - > - memcpy(buf, pvt_data->resp_buf, len); > - pvt_data->resp_len = 0; > - > - return len; > -} > - > -/** > - * ftpm_tee_tpm_op_send() - send TPM commands through the TEE shared memory. > + * ftpm_tee_tpm_op_send_recv() - send TPM commands through the TEE shared memory > + * and retrieve the response. > * @chip: the tpm_chip description as specified in driver/char/tpm/tpm.h > - * @buf: the buffer to send. > - * @len: the number of bytes to send. > + * @buf: the buffer to send and to store the response. > + * @buf_len: the size of the buffer. > + * @cmd_len: the number of bytes to send. > * > * Return: > - * In case of success, returns 0. > + * In case of success, returns the number of bytes received. > * On failure, -errno > */ > -static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t len) > +static int ftpm_tee_tpm_op_send_recv(struct tpm_chip *chip, u8 *buf, > + size_t buf_len, size_t cmd_len) > { > struct ftpm_tee_private *pvt_data = dev_get_drvdata(chip->dev.parent); > size_t resp_len; > @@ -80,16 +54,15 @@ static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t len) > struct tee_param command_params[4]; > struct tee_shm *shm = pvt_data->shm; > > - if (len > MAX_COMMAND_SIZE) { > + if (cmd_len > MAX_COMMAND_SIZE) { > dev_err(&chip->dev, > "%s: len=%zd exceeds MAX_COMMAND_SIZE supported by fTPM TA\n", > - __func__, len); > + __func__, cmd_len); > return -EIO; > } > > memset(&transceive_args, 0, sizeof(transceive_args)); > memset(command_params, 0, sizeof(command_params)); > - pvt_data->resp_len = 0; > > /* Invoke FTPM_OPTEE_TA_SUBMIT_COMMAND function of fTPM TA */ > transceive_args = (struct tee_ioctl_invoke_arg) { > @@ -103,7 +76,7 @@ static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t len) > .attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT, > .u.memref = { > .shm = shm, > - .size = len, > + .size = cmd_len, > .shm_offs = 0, > }, > }; > @@ -115,7 +88,7 @@ static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t len) > return PTR_ERR(temp_buf); > } > memset(temp_buf, 0, (MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE)); > - memcpy(temp_buf, buf, len); > + memcpy(temp_buf, buf, cmd_len); > > command_params[1] = (struct tee_param) { > .attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT, > @@ -156,38 +129,21 @@ static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t len) > __func__, resp_len); > return -EIO; > } > + if (resp_len > buf_len) { > + dev_err(&chip->dev, > + "%s: Invalid size in recv: buf_len=%zd, resp_len=%zd\n", > + __func__, buf_len, resp_len); > + return -EIO; > + } > > - /* sanity checks look good, cache the response */ > - memcpy(pvt_data->resp_buf, temp_buf, resp_len); > - pvt_data->resp_len = resp_len; > - > - return 0; > -} > - > -static void ftpm_tee_tpm_op_cancel(struct tpm_chip *chip) > -{ > - /* not supported */ > -} > - > -static u8 ftpm_tee_tpm_op_status(struct tpm_chip *chip) > -{ > - return 0; > -} > + memcpy(buf, temp_buf, resp_len); > > -static bool ftpm_tee_tpm_req_canceled(struct tpm_chip *chip, u8 status) > -{ > - return false; > + return resp_len; > } > > static const struct tpm_class_ops ftpm_tee_tpm_ops = { > .flags = TPM_OPS_AUTO_STARTUP, > - .recv = ftpm_tee_tpm_op_recv, > - .send = ftpm_tee_tpm_op_send, > - .cancel = ftpm_tee_tpm_op_cancel, > - .status = ftpm_tee_tpm_op_status, > - .req_complete_mask = 0, > - .req_complete_val = 0, > - .req_canceled = ftpm_tee_tpm_req_canceled, > + .send_recv = ftpm_tee_tpm_op_send_recv, > }; > > /* > -- > 2.48.1 > >
