lib: os: mpsc_pbuf: Add optional debug features

Added optional debug prints. Logging cannot be used because
mpsc pbuf is used by the logging.

Added option to clear packet memory after allocation. Option is
enabled in Kconfig.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>

Author: nordic-krch

lib/os/Kconfig

@@ -68,6 +68,13 @@ config MPSC_PBUF
 	  storing variable length packets in a circular way and operate directly
 	  on the buffer memory.
 
+if MPSC_PBUF
+config MPSC_CLEAR_ALLOCATED
+	bool "Clear allocated packet"
+	help
+	  When enabled packet space is zeroed before returning from allocation.
+endif
+
 rsource "Kconfig.cbprintf"
 
 endmenu

lib/os/mpsc_pbuf.c

@@ -5,6 +5,26 @@
  */
 #include <sys/mpsc_pbuf.h>
 
+#define MPSC_PBUF_DEBUG 0
+
+#define MPSC_PBUF_DBG(buffer, ...) do { \
+	if (MPSC_PBUF_DEBUG) { \
+		printk(__VA_ARGS__); \
+		if (buffer) { \
+			mpsc_state_print(buffer); \
+		} \
+	} \
+} while (0)
+
+static inline void mpsc_state_print(struct mpsc_pbuf_buffer *buffer)
+{
+	if (MPSC_PBUF_DEBUG) {
+		printk("wr:%d/%d, rd:%d/%d\n",
+			buffer->wr_idx, buffer->tmp_wr_idx,
+			buffer->rd_idx, buffer->tmp_rd_idx);
+	}
+}
+
 void mpsc_pbuf_init(struct mpsc_pbuf_buffer *buffer,
 		    const struct mpsc_pbuf_buffer_config *cfg)
 {
@@ -188,6 +208,7 @@ union mpsc_pbuf_generic *mpsc_pbuf_alloc(struct mpsc_pbuf_buffer *buffer,
 	bool cont;
 	uint32_t free_wlen;
 
+	MPSC_PBUF_DBG(buffer, "alloc %d words, ", (int)wlen);
 	do {
 		k_spinlock_key_t key;
 		bool wrap;
@@ -230,6 +251,13 @@ union mpsc_pbuf_generic *mpsc_pbuf_alloc(struct mpsc_pbuf_buffer *buffer,
 		}
 	} while (cont);
 
+	MPSC_PBUF_DBG(buffer, "allocated %p ", item);
+
+	if (IS_ENABLED(CONFIG_MPSC_CLEAR_ALLOCATED) && item) {
+		/* During test fill with 0's to simplify message comparison */
+		memset(item, 0, sizeof(int) * wlen);
+	}
+
 	return item;
 }
 
@@ -243,6 +271,7 @@ void mpsc_pbuf_commit(struct mpsc_pbuf_buffer *buffer,
 	item->hdr.valid = 1;
 	buffer->wr_idx = idx_inc(buffer, buffer->wr_idx, wlen);
 	k_spin_unlock(&buffer->lock, key);
+	MPSC_PBUF_DBG(buffer, "committed %p ", item);
 }
 
 void mpsc_pbuf_put_word_ext(struct mpsc_pbuf_buffer *buffer,
@@ -368,6 +397,9 @@ union mpsc_pbuf_generic *mpsc_pbuf_claim(struct mpsc_pbuf_buffer *buffer)
 			}
 		}
 
+		if (!cont) {
+			MPSC_PBUF_DBG(buffer, "claimed: %p ", item);
+		}
 		k_spin_unlock(&buffer->lock, key);
 	} while (cont);
 
@@ -388,6 +420,7 @@ void mpsc_pbuf_free(struct mpsc_pbuf_buffer *buffer,
 	} else {
 		item->skip.len = wlen;
 	}
+	MPSC_PBUF_DBG(buffer, "freed: %p ", item);
 
 	k_spin_unlock(&buffer->lock, key);
 	k_sem_give(&buffer->sem);