On 2019-08-19 17:21, Pierre-Louis Bossart wrote:
On 8/17/19 10:21 AM, Cezary Rojewski wrote:
On 2019-08-15 17:44, Pierre-Louis Bossart wrote:
From: Daniel Baluta <daniel.baluta@xxxxxxx>
Add support for the audio DSP hardware found on NXP i.MX8 platform.
Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxx>
Signed-off-by: Pierre-Louis Bossart
<pierre-louis.bossart@xxxxxxxxxxxxxxx>
+static void imx8_get_reply(struct snd_sof_dev *sdev)
+{
+ struct snd_sof_ipc_msg *msg = sdev->msg;
+ struct sof_ipc_reply reply;
+ int ret = 0;
+
+ if (!msg) {
+ dev_warn(sdev->dev, "unexpected ipc interrupt\n");
+ return;
+ }
+
+ /* get reply */
+ sof_mailbox_read(sdev, sdev->host_box.offset, &reply,
sizeof(reply));
+
+ if (reply.error < 0) {
+ memcpy(msg->reply_data, &reply, sizeof(reply));
+ ret = reply.error;
+ } else {
+ /* reply has correct size? */
+ if (reply.hdr.size != msg->reply_size) {
+ dev_err(sdev->dev, "error: reply expected %zu got %u
bytes\n",
+ msg->reply_size, reply.hdr.size);
+ ret = -EINVAL;
+ }
+
+ /* read the message */
+ if (msg->reply_size > 0)
+ sof_mailbox_read(sdev, sdev->host_box.offset,
+ msg->reply_data, msg->reply_size);
+ }
+
+ msg->reply_error = ret;
+}
Assuming reply.hdr.size is coming from HW IPC regs, msg object is
representing application side - SW, kernel. If so, is msg->reply_size
value an estimated size (which can be overestimated since exact size
may be unknown by the host) -or- the exact size of incoming IPC reply?
The estimated-case is usually permissive as long as assumed size is >=
reply.hdr.size - dev_err needed. In the exact-case, it should be
viewed as a requirement. If such "requirement" fails, is it valid to
read mailbox regardless? Is this to extract some error-debug payload
sent by FW?
Just curious, please feel free to correct me here, Pierre.
I don't quite understand the question. There is no use of HW IPC
registers (as done in SKL) since this is not portable across hardware.
There *may* be information sent over IPC registers but that would have
to be done in platform-specific ways - as will be done for Intel to e.g.
avoid using memory windows that may not be powered.
TLDR:
Was wondering about sof_mailbox_read being invoked regardless of
size-check outcome (dev_err reports size mismatch after all).
Given your answer, guess the error-payload may still be sent back so
it's preferable to read the uplink despite the unexpected circumstances
- size mismatch.
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