Re: [PATCH v3 1/3] i3c: master: dw: Report actual GET CCC payload length on success
"NG, TZE YEE" <[email protected]>
| Newsgroups | org.infradead.lists.linux-i3c,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On 20/6/2026 3:21 am, Frank Li wrote: > On Wed, Jun 10, 2026 at 06:54:06PM -0700, [email protected] wrote: >> From: Adrian Ng Ho Yin <[email protected]> >> >> On successful GET CCC transfers, set dests[0].payload.len from >> RESPONSE_PORT_DATA_LEN so the I3C core receives the number of bytes >> actually read. Core helpers such as i3c_master_getmrl_locked() use >> dest.payload.len after the transfer to interpret the response. >> >> Save the requested length in a local variable before programming the >> hardware so the caller's buffer size is not conflated with the bytes >> received. >> >> Signed-off-by: Adrian Ng Ho Yin <[email protected]> >> Signed-off-by: Tze Yee Ng <[email protected]> >> --- >> drivers/i3c/master/dw-i3c-master.c | 12 +++++++++--- >> 1 file changed, 9 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c >> index 655693a2187e..06fdf8857b9c 100644 >> --- a/drivers/i3c/master/dw-i3c-master.c >> +++ b/drivers/i3c/master/dw-i3c-master.c >> @@ -751,21 +751,24 @@ static int dw_i3c_ccc_set(struct dw_i3c_master *master, >> static int dw_i3c_ccc_get(struct dw_i3c_master *master, struct i3c_ccc_cmd *ccc) >> { >> struct dw_i3c_cmd *cmd; >> + u16 req_len; >> int ret, pos; >> >> pos = dw_i3c_master_get_addr_pos(master, ccc->dests[0].addr); >> if (pos < 0) >> return pos; >> >> + req_len = ccc->dests[0].payload.len; >> + >> struct dw_i3c_xfer *xfer __free(kfree) = dw_i3c_master_alloc_xfer(master, 1); >> if (!xfer) >> return -ENOMEM; >> >> cmd = xfer->cmds; >> cmd->rx_buf = ccc->dests[0].payload.data; >> - cmd->rx_len = ccc->dests[0].payload.len; >> + cmd->rx_len = req_len; >> >> - cmd->cmd_hi = COMMAND_PORT_ARG_DATA_LEN(ccc->dests[0].payload.len) | >> + cmd->cmd_hi = COMMAND_PORT_ARG_DATA_LEN(req_len) | >> COMMAND_PORT_TRANSFER_ARG; > > not sure how req_len help it. Prevously everything copy into cmd. now copy > req_len then copy to cmd, > > No difference? > You are correct. Saving req_len here does nothing useful as payload.len is never getting overwritten. I will drop req_len in v4; keep using ccc->dests[0].payload.len when setting up cmd->rx_len / COMMAND_PORT_ARG_DATA_LEN.>> >> cmd->cmd_lo = COMMAND_PORT_READ_TRANSFER | >> @@ -780,7 +783,10 @@ static int dw_i3c_ccc_get(struct dw_i3c_master *master, struct i3c_ccc_cmd *ccc) >> dw_i3c_master_dequeue_xfer(master, xfer); >> >> ret = xfer->ret; >> - if (xfer->cmds[0].error == RESPONSE_ERROR_IBA_NACK) >> + cmd = &xfer->cmds[0]; >> + if (!ret) >> + ccc->dests[0].payload.len = cmd->rx_len; > > Only this line is validate. > > Frank >> + if (cmd->error == RESPONSE_ERROR_IBA_NACK) >> ccc->err = I3C_ERROR_M2; >> >> return ret; >> -- >> 2.43.7 >> -- linux-i3c mailing list [email protected] http://lists.infradead.org/mailman/listinfo/linux-i3c