trace: core: add trace_flush()

This patch adds a new trace_flush() feature to flush
the last remaining trace messages during panic.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Yan Wang <yan.wang@linux.intel.com>

src/include/reef/dma-trace.h

@@ -72,6 +72,7 @@ int dma_trace_init_complete(struct dma_trace_data *d);
 int dma_trace_host_buffer(struct dma_trace_data *d, struct dma_sg_elem *elem,
 	uint32_t host_size);
 int dma_trace_enable(struct dma_trace_data *d);
+void dma_trace_flush(void *t);
 
 void dtrace_event(const char *e, uint32_t size);
 void dtrace_event_atomic(const char *e, uint32_t length);

src/include/reef/panic.h

@@ -34,6 +34,7 @@
 #include <reef/reef.h>
 #include <reef/mailbox.h>
 #include <reef/interrupt.h>
+#include <reef/trace.h>
 #include <platform/platform.h>
 #include <uapi/ipc.h>
 #include <stdint.h>
@@ -59,8 +60,13 @@ static inline void panic_rewind(uint32_t p, uint32_t stack_rewind_frames)
 
 	/* TODO: send IPC oops message to host */
 
-	/* panic and loop forever */
+	/* panic */
 	platform_panic(p);
+
+	/* flush last trace messages */
+	trace_flush();
+
+	/* and loop forever */
 	while (1) {};
 }
 

src/include/reef/trace.h

@@ -106,6 +106,7 @@ void _trace_error(uint32_t event);
 void _trace_error_value(uint32_t event);
 void _trace_event_atomic(uint32_t event);
 void _trace_error_atomic(uint32_t event);
+void trace_flush(void);
 void trace_off(void);
 void trace_init(struct reef * reef);
 

src/lib/dma-trace.c

@@ -36,6 +36,7 @@
 #include <arch/cache.h>
 #include <platform/timer.h>
 #include <platform/dma.h>
+#include <platform/platform.h>
 #include <reef/lock.h>
 #include <stdint.h>
 
@@ -285,6 +286,40 @@ int dma_trace_enable(struct dma_trace_data *d)
 	return 0;
 }
 
+void dma_trace_flush(void *t)
+{
+	struct dma_trace_buf *buffer = &trace_data->dmatb;
+	uint32_t avail = buffer->avail;
+	int32_t size;
+	int32_t wrap_count;
+
+	/* number of bytes to flush */
+	if (avail > DMA_FLUSH_TRACE_SIZE) {
+		size = DMA_FLUSH_TRACE_SIZE;
+	} else {
+		/* check for buffer wrap */
+		if (buffer->w_ptr > buffer->r_ptr)
+			size = buffer->w_ptr - buffer->r_ptr;
+		else
+			size = buffer->end_addr - buffer->r_ptr +
+				buffer->w_ptr - buffer->addr;
+	}
+
+	/* check for buffer wrap */
+	if (buffer->w_ptr - size < buffer->addr) {
+		wrap_count = buffer->w_ptr - buffer->addr;
+		memcpy(t, buffer->end_addr - (size - wrap_count),
+		       size - wrap_count);
+		memcpy(t + (size - wrap_count), buffer->addr,
+		       wrap_count);
+	} else {
+		memcpy(t, buffer->w_ptr - size, size);
+	}
+
+	/* writeback trace data */
+	dcache_writeback_region(t, size);
+}
+
 static void dtrace_add_event(const char *e, uint32_t length)
 {
 	struct dma_trace_buf *buffer = &trace_data->dmatb;

src/lib/trace.c

@@ -136,6 +136,17 @@ void _trace_event_atomic(uint32_t event)
 	dtrace_event_atomic((const char*)dt, sizeof(uint64_t) * 2);
 }
 
+void trace_flush(void)
+{
+	volatile uint64_t *t;
+
+	/* get mailbox position */
+	t = (volatile uint64_t *)(MAILBOX_TRACE_BASE + trace.pos);
+
+	/* flush dma trace messages */
+	dma_trace_flush((void *)t);
+}
+
 void trace_off(void)
 {
 	trace.enable = 0;

src/platform/apollolake/include/platform/platform.h

@@ -88,6 +88,9 @@ struct reef;
 /* local buffer size of DMA tracing */
 #define DMA_TRACE_LOCAL_SIZE	HOST_PAGE_SIZE
 
+/* trace bytes flushed during panic */
+#define DMA_FLUSH_TRACE_SIZE    (MAILBOX_TRACE_SIZE >> 2)
+
 /* the interval of DMA trace copying */
 #define DMA_TRACE_PERIOD		500000
 

src/platform/baytrail/include/platform/platform.h

@@ -82,6 +82,9 @@ struct reef;
 /* local buffer size of DMA tracing */
 #define DMA_TRACE_LOCAL_SIZE	HOST_PAGE_SIZE
 
+/* trace bytes flushed during panic */
+#define DMA_FLUSH_TRACE_SIZE	(MAILBOX_TRACE_SIZE >> 2)
+
 /* the interval of DMA trace copying */
 #define DMA_TRACE_PERIOD		500000
 

src/platform/cannonlake/include/platform/platform.h

@@ -92,6 +92,9 @@ struct reef;
 /* local buffer size of DMA tracing */
 #define DMA_TRACE_LOCAL_SIZE	HOST_PAGE_SIZE
 
+/* trace bytes flushed during panic */
+#define DMA_FLUSH_TRACE_SIZE    (MAILBOX_TRACE_SIZE >> 2)
+
 /* the interval of DMA trace copying */
 #define DMA_TRACE_PERIOD		500000
 

src/platform/haswell/include/platform/platform.h

@@ -81,6 +81,9 @@ struct reef;
 /* local buffer size of DMA tracing */
 #define DMA_TRACE_LOCAL_SIZE	HOST_PAGE_SIZE
 
+/* trace bytes flushed during panic */
+#define DMA_FLUSH_TRACE_SIZE    (MAILBOX_TRACE_SIZE >> 2)
+
 /* the interval of DMA trace copying */
 #define DMA_TRACE_PERIOD	500000