debug_stream: text_msg: Add CONFIG_SOF_DEBUG_STREAM_SLOT_FORCE_MAX_CPUS

The CONFIG_SOF_DEBUG_STREAM_SLOT_FORCE_MAX_CPUS option limit the
number of debug stream slot section to lower number than the actual
number of cores.  In some situations a high number of cpu sections
shrinks the circular buffer size so much that it limit debugging. With
this option its possible to use fewer sections. The downside is that
the cpus above the number of sections can not send any debug stream
messages.

Signed-off-by: Jyri Sarha <jyri.sarha@linux.intel.com>

Author: Jyri Sarha

src/debug/debug_stream/Kconfig

@@ -45,6 +45,17 @@ config SOF_DEBUG_STREAM_THREAD_INFO_INTERVAL
 	  Decides how often thread info runs and checks execution cycle
 	  statistics and stack usage.
 
+config SOF_DEBUG_STREAM_SLOT_FORCE_MAX_CPUS
+	int "Number of cpu sections slot is divided to"
+	default MP_MAX_NUM_CPUS
+	range 1 MP_MAX_NUM_CPUS
+	help
+	  In some situations a high number of cpu sections shrinks the
+	  circular buffer size so much that it limit debugging. With
+	  this option its possible to use fewer sections. The downside
+	  is that the cpus above the number of sections can not send
+	  any debug stream messages.
+
 config SOF_DEBUG_STREAM_TEXT_MSG
 	bool "Enable text message sending through Debug-Stream"
 	help

src/debug/debug_stream/debug_stream_slot.c

@@ -19,7 +19,7 @@ struct cpu_mutex {
 } __aligned(CONFIG_DCACHE_LINE_SIZE);
 
 /* CPU specific mutexes for each circular buffer */
-static struct cpu_mutex cpu_mutex[CONFIG_MP_MAX_NUM_CPUS];
+static struct cpu_mutex cpu_mutex[CONFIG_SOF_DEBUG_STREAM_SLOT_FORCE_MAX_CPUS];
 
 #ifdef CONFIG_INTEL_ADSP_DEBUG_SLOT_MANAGER
 static struct debug_stream_slot_hdr *dbg_stream_slot;
@@ -54,6 +54,12 @@ debug_stream_get_circular_buffer(struct debug_stream_section_descriptor *desc, u
 		return NULL;
 	}
 
+	if (core >= CONFIG_SOF_DEBUG_STREAM_SLOT_FORCE_MAX_CPUS) {
+		LOG_DBG("No section for cpu %u >= %u ", core,
+			CONFIG_SOF_DEBUG_STREAM_SLOT_FORCE_MAX_CPUS);
+		return NULL;
+	}
+
 	*desc = hdr->section_desc[core];
 	LOG_DBG("Section %u (desc %u %u %u)", core, desc->core_id, desc->buf_words, desc->offset);
 
@@ -116,18 +122,18 @@ int debug_stream_slot_send_record(struct debug_stream_record *rec)
 static int debug_stream_slot_init(void)
 {
 	struct debug_stream_slot_hdr *hdr = debug_stream_get_slot();
+	unsigned int max_num_cpus = CONFIG_SOF_DEBUG_STREAM_SLOT_FORCE_MAX_CPUS;
 	size_t hdr_size = ALIGN_UP(offsetof(struct debug_stream_slot_hdr,
-					    section_desc[CONFIG_MP_MAX_NUM_CPUS]),
+					    section_desc[max_num_cpus]),
 				   CONFIG_DCACHE_LINE_SIZE);
 	size_t section_area_size = ADSP_DW_SLOT_SIZE - hdr_size;
-	size_t section_size = ALIGN_DOWN(section_area_size /
-					 CONFIG_MP_MAX_NUM_CPUS,
+	size_t section_size = ALIGN_DOWN(section_area_size / max_num_cpus,
 					 CONFIG_DCACHE_LINE_SIZE);
 	size_t offset = hdr_size;
 	int i;
 
 	LOG_INF("%u sections of %u bytes, hdr %u, section area %u",
-		CONFIG_MP_MAX_NUM_CPUS, section_size, hdr_size,
+		max_num_cpus, section_size, hdr_size,
 		section_area_size);
 
 #ifdef CONFIG_INTEL_ADSP_DEBUG_SLOT_MANAGER
@@ -142,9 +148,9 @@ static int debug_stream_slot_init(void)
 
 	hdr->hdr.magic = DEBUG_STREAM_IDENTIFIER;
 	hdr->hdr.hdr_size = hdr_size;
-	hdr->total_size = hdr_size + CONFIG_MP_MAX_NUM_CPUS * section_size;
-	hdr->num_sections = CONFIG_MP_MAX_NUM_CPUS;
-	for (i = 0; i < CONFIG_MP_MAX_NUM_CPUS; i++) {
+	hdr->total_size = hdr_size + max_num_cpus * section_size;
+	hdr->num_sections = max_num_cpus;
+	for (i = 0; i < max_num_cpus; i++) {
 		hdr->section_desc[i].core_id = i;
 		hdr->section_desc[i].buf_words =
 			(section_size - offsetof(struct debug_stream_circular_buf, data[0]))/
@@ -154,7 +160,7 @@ static int debug_stream_slot_init(void)
 			i, section_size, offset);
 		offset += section_size;
 	}
-	for (i = 0; i < CONFIG_MP_MAX_NUM_CPUS; i++) {
+	for (i = 0; i < max_num_cpus; i++) {
 		struct debug_stream_section_descriptor desc = { 0 };
 		struct debug_stream_circular_buf *buf =
 			debug_stream_get_circular_buffer(&desc, i);