shell: add log_status and mtrace_dump commands

Add two new SOF shell commands for in-firmware log introspection
without rebuilding or attaching host-side tooling.

  sof log_status   - list every Zephyr log backend with its index,
                     internal id, active/inactive state and name,
                     plus the total number of registered log sources
                     in the local domain. Read-only, uses Zephyr's
                     public log_backend_*/log_src_cnt_get() API.

  sof mtrace_dump  - snapshot the unread portion of the ADSP mtrace
                     SRAM ring buffer and print it to the shell
                     without advancing host_ptr, so the host-side
                     mtrace-reader.py keeps receiving the same bytes.

The mtrace slot is re-acquired through adsp_dw_request_slot() when
CONFIG_INTEL_ADSP_DEBUG_SLOT_MANAGER=y (the slot manager returns the
already allocated slot), otherwise via ADSP_DW->slots[] directly. The
slot layout mirrors the one in zephyr/subsys/logging/backends/
log_backend_adsp_mtrace.c.

Two new Kconfigs (default y):
  CONFIG_SOF_SHELL_LOG_INFO     (depends on LOG)
  CONFIG_SOF_SHELL_MTRACE_DUMP  (depends on LOG_BACKEND_ADSP_MTRACE)

Per-source runtime log_level was intentionally not added: it would
require CONFIG_LOG_RUNTIME_FILTERING=y (extra per-call overhead) and
Zephyr already ships an equivalent 'log' shell command
(CONFIG_LOG_CMDS=y). Update zephyr/shell.md.

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>

Author: lrgirdwo

zephyr/Kconfig

@@ -488,6 +488,35 @@ config SOF_SHELL_SCHED_INFO
 	  own lock during the walk; schedulers without an implementation are
 	  silently skipped.
 
+config SOF_SHELL_LOG_INFO
+	bool "Log subsystem status command"
+	default y
+	depends on SHELL && LOG
+	help
+	  Enables the 'sof log_status' shell command, which lists every
+	  registered Zephyr log backend with its index, internal id,
+	  active/inactive state and name, plus the total number of
+	  registered log sources in the local domain.
+
+	  Read-only and cheap; useful for confirming which backends
+	  (uart_console, adsp_mtrace, adsp_hda, ...) are alive without
+	  having to enable CONFIG_LOG_RUNTIME_FILTERING and the much
+	  larger Zephyr 'log' shell module.
+
+config SOF_SHELL_MTRACE_DUMP
+	bool "mtrace SRAM buffer snapshot command"
+	default y
+	depends on SHELL && LOG_BACKEND_ADSP_MTRACE
+	help
+	  Enables the 'sof mtrace_dump' shell command which prints the
+	  unread portion of the ADSP mtrace SRAM ring buffer (the same
+	  buffer normally consumed by host-side mtrace-reader.py).
+
+	  The snapshot does NOT advance the host_ptr, so it is safe to
+	  use while a host consumer is running: the host will still
+	  receive every byte. Useful when no host driver is attached
+	  (e.g. early bring-up over UART shell only).
+
 endmenu # SOF shell commands
 
 config SOF_VREGIONS

zephyr/shell.md

@@ -87,7 +87,7 @@ debug or testing. Items get ticked off as commands land on `topic/shell`.
 | IPC inject | `ipc_inject <hex>`, `ipc_queue` | TODO |
 | Audio buffers | `buffer_list`, `buffer_info <id>` | **DONE (task 2)** |
 | **Scheduler** | `sched_tasks`, `sched_load`, `task_info <task>` | **DONE (task 3)** |
-| Logging / trace | `log_level <component> <lvl>`, `log_filter`, `mtrace_dump`, `trace_stats` | TODO |
+| Logging / trace | `log_status`, `mtrace_dump` (snapshot) | **DONE (task 4)** &mdash; runtime per-source `log_level` deferred (needs `CONFIG_LOG_RUNTIME_FILTERING`, see notes) |
 | Telemetry / perf | `perf_status`, `perf_reset`, `cpu_load` | TODO |
 | Notifications | `notify_subscribers`, `notify_stats` | TODO |
 | Debug window / mailbox | `dbgwin_dump <slot>`, `mailbox_hex` | TODO |
@@ -112,7 +112,7 @@ debug or testing. Items get ticked off as commands land on `topic/shell`.
 1. **`ipc_stats` / `ipc_last`** &mdash; DONE.
 2. **`buffer_list` / `buffer_info`** &mdash; DONE.
 3. **`sched_tasks` / `sched_load`** &mdash; DONE.
-4. `log_level` / `mtrace_dump` &mdash; runtime log tuning without rebuild.
+4. **`log_status` / `mtrace_dump`** &mdash; DONE.
 5. `crash_log` / `bt` &mdash; pair with the `crash-*` artifacts in the tree.
 6. `perf_status` &mdash; wraps SOF telemetry counters.
 7. `dai_list` / `dma_chan_status` &mdash; link/DMA blind spot.
@@ -221,3 +221,47 @@ debug or testing. Items get ticked off as commands land on `topic/shell`.
   targets).
 - `task_info <uid>` lookup, deadline-miss counts and per-core
   aggregation could be added on top of the same op.
+
+## Task 4 &mdash; `log_status` / `mtrace_dump`
+
+### Commands
+
+| Command | Description |
+|---|---|
+| `sof log_status` | List every Zephyr log backend (idx, internal id, active state, name) plus the total number of registered log sources in the local domain. Read-only. |
+| `sof mtrace_dump` | Print the unread portion of the ADSP mtrace SRAM ring buffer as a snapshot, *without* advancing `host_ptr`. Safe to use while host-side `mtrace-reader.py` is running. |
+
+### Implementation
+
+- `log_status` uses Zephyr's public log backend API
+  (`log_backend_count_get()`, `log_backend_get()`,
+  `log_backend_is_active()`, `log_backend_id_get()`,
+  `log_src_cnt_get()`); no new state is added.
+- `mtrace_dump` re-acquires the existing mtrace slot:
+  - With `CONFIG_INTEL_ADSP_DEBUG_SLOT_MANAGER=y` (default on PTL/MTL/LNL):
+    via `adsp_dw_request_slot()` with the same descriptor type
+    (`ADSP_DW_SLOT_DEBUG_LOG | core 0`); the slot manager returns the
+    already-allocated slot.
+  - Otherwise: directly indexes
+    `ADSP_DW->slots[ADSP_DW_SLOT_NUM_MTRACE]`.
+  - The slot layout (`{host_ptr, dsp_ptr, data[]}`) mirrors the one in
+    [zephyr/subsys/logging/backends/log_backend_adsp_mtrace.c](../../zephyr/subsys/logging/backends/log_backend_adsp_mtrace.c).
+  - We read from `host_ptr` to `dsp_ptr` byte-by-byte and write to the
+    shell, but never store back to `host_ptr`, so the host-side
+    consumer keeps seeing the same bytes.
+- Two new Kconfigs (default `y`):
+  - `CONFIG_SOF_SHELL_LOG_INFO` (depends on `LOG`)
+  - `CONFIG_SOF_SHELL_MTRACE_DUMP` (depends on `LOG_BACKEND_ADSP_MTRACE`)
+- Shell commands in [zephyr/sof_shell.c](zephyr/sof_shell.c).
+
+### Notes / follow-ups
+
+- Per-source runtime `log_level` setting was deliberately deferred: it
+  requires `CONFIG_LOG_RUNTIME_FILTERING=y` (extra per-call overhead)
+  and Zephyr already ships an equivalent `log` shell command
+  (`CONFIG_LOG_CMDS=y`). If we ever need it we should reuse Zephyr's
+  command rather than reimplement it.
+- `mtrace_dump` shows raw text exactly as the backend formatted it; a
+  future option could format output in pages or filter by severity.
+- A `mtrace_dump --consume` mode (advance `host_ptr`) is intentionally
+  not provided to avoid silently breaking host-side tooling.

zephyr/sof_shell.c

@@ -1855,6 +1855,101 @@ __cold static int cmd_sof_sched_load(const struct shell *sh,
 
 #endif /* CONFIG_SOF_SHELL_SCHED_INFO */
 
+#if CONFIG_SOF_SHELL_LOG_INFO
+
+#include <zephyr/logging/log_backend.h>
+#include <zephyr/logging/log_ctrl.h>
+
+__cold static int cmd_sof_log_status(const struct shell *sh,
+				     size_t argc, char *argv[])
+{
+	int n = log_backend_count_get();
+	int i;
+
+	shell_print(sh, "Log backends: %d, sources: %u",
+		    n, log_src_cnt_get(Z_LOG_LOCAL_DOMAIN_ID));
+	shell_print(sh, "  idx  id  active  name");
+
+	for (i = 0; i < n; i++) {
+		const struct log_backend *be = log_backend_get(i);
+
+		if (!be)
+			continue;
+		shell_print(sh, "  %3d  %3u   %-3s    %s",
+			    i, log_backend_id_get(be),
+			    log_backend_is_active(be) ? "yes" : "no",
+			    be->name ? be->name : "?");
+	}
+
+	return 0;
+}
+
+#endif /* CONFIG_SOF_SHELL_LOG_INFO */
+
+#if CONFIG_SOF_SHELL_MTRACE_DUMP
+
+#include <adsp_debug_window.h>
+
+/* must match the layout used by zephyr/subsys/logging/backends/log_backend_adsp_mtrace.c */
+struct sof_shell_mtrace_slot {
+	uint32_t host_ptr;
+	uint32_t dsp_ptr;
+	uint8_t data[ADSP_DW_SLOT_SIZE - 2 * sizeof(uint32_t)];
+} __packed;
+
+#define SOF_SHELL_MTRACE_BUF_SIZE (ADSP_DW_SLOT_SIZE - 2 * sizeof(uint32_t))
+#define SOF_SHELL_MTRACE_TYPE(core) \
+	(ADSP_DW_SLOT_DEBUG_LOG | ((core) & ADSP_DW_SLOT_CORE_MASK))
+
+__cold static int cmd_sof_mtrace_dump(const struct shell *sh,
+				      size_t argc, char *argv[])
+{
+	struct sof_shell_mtrace_slot *slot;
+	uint32_t r, w, len, i;
+
+#ifdef CONFIG_INTEL_ADSP_DEBUG_SLOT_MANAGER
+	struct adsp_dw_desc desc = { .type = SOF_SHELL_MTRACE_TYPE(0) };
+
+	slot = adsp_dw_request_slot(&desc, NULL);
+#else
+	slot = (struct sof_shell_mtrace_slot *)
+		ADSP_DW->slots[ADSP_DW_SLOT_NUM_MTRACE];
+#endif
+	if (!slot) {
+		shell_print(sh, "mtrace slot not available");
+		return -ENODEV;
+	}
+
+	r = slot->host_ptr;
+	w = slot->dsp_ptr;
+
+	if (r == w) {
+		shell_print(sh, "mtrace: empty (host_ptr=dsp_ptr=%u)", r);
+		return 0;
+	}
+
+	if (w > r)
+		len = w - r;
+	else
+		len = SOF_SHELL_MTRACE_BUF_SIZE - r + w;
+
+	shell_print(sh,
+		    "mtrace: host_ptr=%u dsp_ptr=%u unread=%u bytes (snapshot)",
+		    r, w, len);
+
+	/* print byte-by-byte without advancing host_ptr; preserves host consumer */
+	for (i = 0; i < len; i++) {
+		uint32_t off = (r + i) % SOF_SHELL_MTRACE_BUF_SIZE;
+
+		shell_fprintf(sh, SHELL_NORMAL, "%c", slot->data[off]);
+	}
+	shell_fprintf(sh, SHELL_NORMAL, "\n");
+
+	return 0;
+}
+
+#endif /* CONFIG_SOF_SHELL_MTRACE_DUMP */
+
 SHELL_STATIC_SUBCMD_SET_CREATE(sof_commands,
 	SHELL_CMD(test_inject_sched_gap, NULL,
 		  "Inject a gap to audio scheduling\n",
@@ -2031,6 +2126,18 @@ SHELL_STATIC_SUBCMD_SET_CREATE(sof_commands,
 		  cmd_sof_sched_load),
 #endif
 
+#if CONFIG_SOF_SHELL_LOG_INFO
+	SHELL_CMD(log_status, NULL,
+		  "List Zephyr log backends with state and source count\n",
+		  cmd_sof_log_status),
+#endif
+
+#if CONFIG_SOF_SHELL_MTRACE_DUMP
+	SHELL_CMD(mtrace_dump, NULL,
+		  "Snapshot the mtrace SRAM ring buffer (does not advance host_ptr)\n",
+		  cmd_sof_mtrace_dump),
+#endif
+
 	SHELL_SUBCMD_SET_END
 );