drivers: dma: sdma: Make access to DMA channel stats atomic

DMA channel stats like pending_length or free is not protected
and can be modified in parallel by a consumer and a producer.

This can result in non-atomic updates which in turn will result
in using stale data.

Fix this by making regions of code accessing dma stats atomic.

Fixes: e94c86f ("drivers: dma: Add initial support for NXP SDMA")
Signed-off-by: Daniel Baluta <[email protected]>

Author: dbaluta

drivers/dma/dma_nxp_sdma.c

@@ -376,11 +376,14 @@ static int dma_nxp_sdma_get_status(const struct device *dev, uint32_t channel,
 {
 	struct sdma_dev_data *dev_data = dev->data;
 	struct sdma_channel_data *chan_data;
+	unsigned int key;
 
 	chan_data = &dev_data->chan[channel];
 
+	key = irq_lock();
 	stat->free = chan_data->stat.free;
 	stat->pending_length = chan_data->stat.pending_length;
+	irq_unlock(key);
 
 	return 0;
 }
@@ -390,18 +393,21 @@ static int dma_nxp_sdma_reload(const struct device *dev, uint32_t channel, uint3
 {
 	struct sdma_dev_data *dev_data = dev->data;
 	struct sdma_channel_data *chan_data;
+	unsigned int key;
 
 	chan_data = &dev_data->chan[channel];
 
 	if (!size) {
 		return 0;
 	}
 
+	key = irq_lock();
 	if (chan_data->direction == MEMORY_TO_PERIPHERAL) {
 		dma_nxp_sdma_produce(chan_data, size);
 	} else {
 		dma_nxp_sdma_consume(chan_data, size);
 	}
+	irq_unlock(key);
 
 	return 0;
 }