base_fw: Extend fw_config with information about the host buffer size

The host buffer default or minimum size can be platform dependent and it is
not know by the host.
It is in sole discretion of the firmware and the hardware where it is
running and can be changed by recompiling the firmware.

Add new tlv item to fw_config with ID 33 and store the host DMA default
period size, which is the indication of the default, minimum size of the
host buffer in ms.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

Author: ujfalusi

src/audio/base_fw.c

@@ -44,6 +44,27 @@ DECLARE_TR_CTX(basefw_comp_tr, SOF_UUID(basefw_uuid), LOG_LEVEL_INFO);
 static struct ipc4_system_time_info global_system_time_info;
 static uint64_t global_cycle_delta;
 
+__cold static uint32_t get_host_buffer_size(void)
+{
+	struct sof_dma *dma_host;
+	uint32_t periods;
+
+	assert_can_be_cold();
+
+	dma_host = sof_dma_get(SOF_DMA_DIR_HMEM_TO_LMEM, 0, SOF_DMA_DEV_HOST,
+			       SOF_DMA_ACCESS_SHARED);
+	if (!dma_host) {
+		LOG_WRN("Failed to get host DMA channel");
+		return 0;
+	}
+
+	periods = dma_host->plat_data.period_count;
+
+	sof_dma_put(dma_host);
+
+	return periods;
+}
+
 __cold static int basefw_config(uint32_t *data_offset, char *data)
 {
 	uint16_t version[4] = {SOF_MAJOR, SOF_MINOR, SOF_MICRO, SOF_BUILD};
@@ -124,6 +145,11 @@ __cold static int basefw_config(uint32_t *data_offset, char *data)
 
 	tuple = tlv_next(tuple);
 
+	tlv_value_uint32_set(tuple, IPC4_FW_MIN_HOST_BUFFER_PERIODS,
+			     get_host_buffer_size());
+
+	tuple = tlv_next(tuple);
+
 	/* add platform specific tuples */
 	basefw_vendor_fw_config(&plat_data_offset, (char *)tuple);
 

src/include/ipc4/base_fw.h

@@ -373,6 +373,8 @@ enum ipc4_fw_config_params {
 	IPC4_DMI_FORCE_L1_EXIT = 28,
 	/* FW context save on D3 entry */
 	IPC4_FW_CONTEXT_SAVE = 29,
+	/* Minimum size of host buffer in ms */
+	IPC4_FW_MIN_HOST_BUFFER_PERIODS = 33,
 	/* Total number of FW config parameters  */
 	IPC4_FW_CFG_PARAMS_COUNT,
 	/* Max config parameter id */