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Upstream: clarify baytrail IPC #564
Description
Question from @dbaluta:
static int byt_send_msg(struct snd_sof_dev *sdev, struct snd_sof_ipc_msg *msg)
{
u64 cmd = msg->header;
/* send the message */
sof_mailbox_write(sdev, sdev->host_box.offset, msg->msg_data,
msg->msg_size);
snd_sof_dsp_write64(sdev, BYT_DSP_BAR, SHIM_IPCX,
cmd | SHIM_BYT_IPCX_BUSY);
return 0;
}why do we mask cmd with shim bitfields?
Activity
xiulipan commentedon Jan 22, 2019
@plbossart
This is not mask. This is some assemble of the register. The highest bit of SHIM_IPCX is busy bit.
#define SHIM_BYT_IPCX_BUSY BIT_ULL(63)And we put the our ipc cmd header into the lower 32 bit as data for this ipc. Will check register cmd matches mailbox cmd later in DSP FW.
dbaluta commentedon Jan 29, 2019
@xiulipan for me it looked like 'cmd' is never used by the FW. Can you point me where there is this check for cmd matching cmd mailbox in DSP FW?
I couldn't find it so for this reason I've created #586
Anyhow, due to my amazing skills with github I deleted my local branch so PR got automatically closed. I've reopened it now.
xiulipan commentedon Feb 10, 2019
@dbaluta I will continue to check that within #586
Thanks for pointing out some old remaining unused thing. Yes the CMD in SHIM is not used beside some log message I think.
dbaluta commentedon Feb 10, 2019
@xiulipan thanks for looking into this. The log message in SOF was cleaned up with
thesofproject/sof@7c37501
plbossart commentedon Jun 10, 2019
closing, we've removed the use of the cmd argument in the kernel
cachefiles: fix slab-use-after-free in cachefiles_ondemand_daemon_read()
btrfs: do not WARN_ON() if we have PageError set
ring-buffer: Do not trigger WARN_ON() due to a commit_overrun