trace: dma: Add atomic and nowait DMA tracing support.

Add support for DMA trace to run in atomic and IRQ contexts. Currently
DMA trace would sleep between DMA copies and enter atomic state when
inserting new tarce data into the trace buffer.

This patch adds new DMA _nowait() APIs that dont sleep and _atomic() APIs
for trace logging that can be safely called in atomic context.

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

Author: lrgirdwo

src/audio/dma-trace.c

@@ -47,9 +47,7 @@ static uint64_t trace_work(void *data, uint64_t delay)
 	struct dma_trace_buf *buffer = &d->dmatb;
 	struct dma_sg_config *config = &d->config;
 	unsigned long flags;
-	int32_t offset = 0;
 	uint32_t avail = buffer->avail;
-	uint32_t bytes_copied = 0;
 	uint32_t size;
 	uint32_t hsize;
 	uint32_t lsize;
@@ -58,53 +56,51 @@ static uint64_t trace_work(void *data, uint64_t delay)
 	if (avail == 0)
 		return DMA_TRACE_US;
 
+	/* make sure we dont write more than buffer */
+	if (avail > DMA_TRACE_LOCAL_SIZE)
+		avail = DMA_TRACE_LOCAL_SIZE;
+
 	/* copy to host in sections if we wrap */
-	while (avail > 0) {
-
-		lsize = hsize = avail;
-
-		/* host buffer wrap ? */
-		if (d->host_offset + buffer->avail > d->host_size)
-			hsize = d->host_offset + buffer->avail - d->host_size;
-
-		/* local buffer wrap ? */
-		if (buffer->r_ptr > buffer->w_ptr)
-			lsize = buffer->end_addr - buffer->r_ptr;
-
-		/* get smallest size */
-		if (hsize < lsize)
-			size = hsize;
-		else
-			size = lsize;
-
-		/* writeback trace data */
-		dcache_writeback_region((void*)buffer->r_ptr, size);
-
-		/* copy this section to host */
-		offset = dma_copy_to_host(&d->dc, config, d->host_offset,
-			buffer->r_ptr, size);
-		if (offset < 0) {
-			trace_buffer_error("ebb");
-			goto out;
-		}
-
-		/* update host pointer and check for wrap */
-		d->host_offset += size;
-		if (d->host_offset + size >= d->host_size)
-			d->host_offset = 0;
-
-		/* update local pointer and check for wrap */
-		buffer->r_ptr += size;
-		if (buffer->r_ptr >= buffer->end_addr)
-			buffer->r_ptr = buffer->addr;
-
-		avail -= size;
-		bytes_copied += size;
+	lsize = hsize = avail;
+
+	/* host buffer wrap ? */
+	if (d->host_offset + avail > d->host_size)
+		hsize = d->host_size - d->host_offset;
+
+	/* local buffer wrap ? */
+	if (buffer->r_ptr + avail > buffer->end_addr)
+		lsize = buffer->end_addr - buffer->r_ptr;
+
+	/* get smallest size */
+	if (hsize < lsize)
+		size = hsize;
+	else
+		size = lsize;
+
+	/* writeback trace data */
+	dcache_writeback_region((void*)buffer->r_ptr, size);
+
+	/* copy this section to host */
+	size = dma_copy_to_host_nowait(&d->dc, config, d->host_offset,
+		buffer->r_ptr, size);
+	if (size < 0) {
+		trace_buffer_error("ebb");
+		goto out;
 	}
 
+	/* update host pointer and check for wrap */
+	d->host_offset += size;
+	if (d->host_offset + size >= d->host_size)
+		d->host_offset = 0;
+
+	/* update local pointer and check for wrap */
+	buffer->r_ptr += size;
+	if (buffer->r_ptr >= buffer->end_addr)
+		buffer->r_ptr = buffer->addr;
+
 out:
 	spin_lock_irq(&d->lock, flags);
-	buffer->avail -= bytes_copied;
+	buffer->avail -= size;
 	spin_unlock_irq(&d->lock, flags);
 
 	/* reschedule the trace copying work */
@@ -172,32 +168,28 @@ int dma_trace_enable(struct dma_trace_data *d)
 {
 	/* validate DMA context */
 	if (d->dc.dmac == NULL || d->dc.chan < 0) {
-		trace_buffer_error("eem");
+		trace_error_atomic(TRACE_CLASS_BUFFER, "eem");
 		return -ENODEV;
 	}
 
 	/* TODO: fix crash when enabled */
-	//d->enabled = 1;
+	d->enabled = 1;
 	work_schedule_default(&d->dmat_work, DMA_TRACE_US);
 	return 0;
 }
 
-void dtrace_event(const char *e, uint32_t length)
+static void dtrace_add_event(const char *e, uint32_t length)
 {
-	struct dma_trace_buf *buffer = NULL;
-	int margin = 0;
-	unsigned long flags;
+	struct dma_trace_buf *buffer = &trace_data->dmatb;
+	int margin;
 
-	if (trace_data == NULL || length == 0)
-		return;
+	margin = buffer->end_addr - buffer->w_ptr;
 
-	buffer = &trace_data->dmatb;
-	if (buffer == NULL)
+	/* validate */
+	if (margin <= 0) {
+		trace_buffer_error("emm");
 		return;
-
-	spin_lock_irq(&trace_data->lock, flags);
-
-	margin = buffer->end_addr - buffer->w_ptr;
+	}
 
 	/* check for buffer wrap */
 	if (margin > length) {
@@ -216,9 +208,45 @@ void dtrace_event(const char *e, uint32_t length)
 	}
 
 	buffer->avail += length;
+}
+
+void dtrace_event(const char *e, uint32_t length)
+{
+	struct dma_trace_buf *buffer = NULL;
+	unsigned long flags;
+
+	if (trace_data == NULL || length == 0)
+		return;
+
+	if (!trace_data->enabled)
+		return;
+
+	buffer = &trace_data->dmatb;
+	if (buffer == NULL)
+		return;
+
+	spin_lock_irq(&trace_data->lock, flags);
+	dtrace_add_event(e, length);
 	spin_unlock_irq(&trace_data->lock, flags);
 
 	/* schedule copy now if buffer > 50% full */
 	if (trace_data->enabled && buffer->avail >= (DMA_TRACE_LOCAL_SIZE / 2))
 		work_reschedule_default(&trace_data->dmat_work, 100);
 }
+
+void dtrace_event_atomic(const char *e, uint32_t length)
+{
+	struct dma_trace_buf *buffer = NULL;
+
+	if (trace_data == NULL || length == 0)
+		return;
+
+	if (!trace_data->enabled)
+		return;
+
+	buffer = &trace_data->dmatb;
+	if (buffer == NULL)
+		return;
+
+	dtrace_add_event(e, length);
+}

src/include/reef/audio/dma-trace.h

@@ -69,5 +69,6 @@ int dma_trace_host_buffer(struct dma_trace_data *d, struct dma_sg_elem *elem,
 int dma_trace_enable(struct dma_trace_data *d);
 
 void dtrace_event(const char *e, uint32_t size);
+void dtrace_event_atomic(const char *e, uint32_t length);
 
 #endif

src/include/reef/dma.h

@@ -249,9 +249,13 @@ static inline void dma_copy_free(struct dma_copy *dc)
 /* DMA copy data from host to DSP */
 int dma_copy_from_host(struct dma_copy *dc, struct dma_sg_config *host_sg,
 	int32_t host_offset, void *local_ptr, int32_t size);
+int dma_copy_from_host_nowait(struct dma_copy *dc, struct dma_sg_config *host_sg,
+	int32_t host_offset, void *local_ptr, int32_t size);
 
 /* DMA copy data from DSP to host */
 int dma_copy_to_host(struct dma_copy *dc, struct dma_sg_config *host_sg,
 	int32_t host_offset, void *local_ptr, int32_t size);
+int dma_copy_to_host_nowait(struct dma_copy *dc, struct dma_sg_config *host_sg,
+	int32_t host_offset, void *local_ptr, int32_t size);
 
 #endif

src/include/reef/trace.h

@@ -95,33 +95,45 @@
 
 void _trace_event(uint32_t event);
 void _trace_error(uint32_t event);
+void _trace_event_atomic(uint32_t event);
+void _trace_error_atomic(uint32_t event);
 void trace_off(void);
 void trace_init(struct reef * reef);
 
 #if TRACE
 
 #define trace_event(__c, __e) \
 	_trace_event(__c | (__e[0] << 16) | (__e[1] <<8) | __e[2])
+#define trace_event_atomic(__c, __e) \
+	_trace_event_atomic(__c | (__e[0] << 16) | (__e[1] <<8) | __e[2])
 
 #define trace_value(x)	_trace_event(x)
+#define trace_value_atomic(x)	_trace_event_atomic(x)
 
 #define trace_point(x) platform_trace_point(x)
 
 /* verbose tracing */
 #if TRACEV
 #define tracev_event(__c, __e) trace_event(__c, __e)
 #define tracev_value(x)	_trace_event(x)
+#define tracev_event_atomic(__c, __e) trace_event_atomic(__c, __e)
+#define tracev_value_atomic(x)	_trace_event_atomic(x)
 #else
 #define tracev_event(__c, __e)
 #define tracev_value(x)
+#define tracev_event_atomic(__c, __e)
+#define tracev_value_atomic(x)
 #endif
 
 /* error tracing */
 #if TRACEE
 #define trace_error(__c, __e) \
 	_trace_error(__c | (__e[0] << 16) | (__e[1] <<8) | __e[2])
+#define trace_error_atomic(__c, __e) \
+	_trace_error_atomic(__c | (__e[0] << 16) | (__e[1] <<8) | __e[2])
 #else
 #define trace_error(__c, __e)
+#define trace_error_atomic(__c, __e)
 #endif
 
 #else