ASoC: SOF: add fw_info_box support

FW can share some information with host driver, .e.g fw status, pipeline
status and volume status. On ipc4 platform it is located in memory
windows 0 with size of struct sof_ipc4_fw_reg.

With this patch, ipc4 driver can find fw information in fw_info_box

Signed-off-by: Rander Wang <[e-mail]>
Reviewed-by: Pierre-Louis Bossart <[e-mail]>
Reviewed-by: Ranjani Sridharan <[e-mail]>
Reviewed-by: Bard Liao <[e-mail]>
Signed-off-by: Peter Ujfalusi <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

sound/soc/sof/ipc4-priv.h

···
 #include "sof-priv.h"
 
 /* The DSP window indices are fixed */
+#define SOF_IPC4_INBOX_WINDOW_IDX	0
 #define SOF_IPC4_OUTBOX_WINDOW_IDX	1
 #define SOF_IPC4_DEBUG_WINDOW_IDX	2
 

sound/soc/sof/ipc4.c

···
 #include <sound/sof/ipc4/header.h>
 #include "sof-priv.h"
 #include "sof-audio.h"
+#include "ipc4-fw-reg.h"
 #include "ipc4-priv.h"
 #include "ops.h"
 
···
 	outbox_offset = snd_sof_dsp_get_window_offset(sdev, SOF_IPC4_OUTBOX_WINDOW_IDX);
 	outbox_size = SOF_IPC4_MSG_MAX_SIZE;
 
+	sdev->fw_info_box.offset = snd_sof_dsp_get_window_offset(sdev, SOF_IPC4_INBOX_WINDOW_IDX);
+	sdev->fw_info_box.size = sizeof(struct sof_ipc4_fw_registers);
 	sdev->dsp_box.offset = inbox_offset;
 	sdev->dsp_box.size = inbox_size;
 	sdev->host_box.offset = outbox_offset;

sound/soc/sof/sof-priv.h

···
 
 	/* IPC */
 	struct snd_sof_ipc *ipc;
+	struct snd_sof_mailbox fw_info_box;	/* FW shared memory */
 	struct snd_sof_mailbox dsp_box;		/* DSP initiated IPC */
 	struct snd_sof_mailbox host_box;	/* Host initiated IPC */
 	struct snd_sof_mailbox stream_box;	/* Stream position update */