drivers: dma: dma_mcux_lpc: Add register backup and restore

Add for the case that the registers are not kept in some
low power modes.

Signed-off-by: Jason Yu <zejiang.yu@nxp.com>

Author: zejiang0jason

drivers/dma/dma_mcux_lpc.c

@@ -29,6 +29,28 @@
 
 LOG_MODULE_REGISTER(dma_mcux_lpc, CONFIG_DMA_LOG_LEVEL);
 
+#if CONFIG_PM_DEVICE
+/*
+ * Data structures to backup DMA registers when the
+ * register content lost in low power modes.
+ */
+struct dma_backup_reg {
+	/*
+	 * Backup the control registers.
+	 * Don't need to backup CTRL and SRAMBASE, they
+	 * are configured in function DMA_Init.
+	 */
+	uint32_t enableset;	/* Register ENABLESET */
+	uint32_t intenset;	/* Register INTENSET */
+};
+
+struct dma_ch_backup_reg {
+	/* Don't need to backup status register CTLSTAT. */
+	uint32_t cfg;		/* Register CFG */
+	uint32_t xfercfg;	/* Register XFERCFG */
+};
+#endif /* CONFIG_PM_DEVICE */
+
 struct dma_mcux_lpc_config {
 	DMA_Type *base;
 	uint32_t otrig_base_address;
@@ -54,6 +76,9 @@ struct channel_data {
 	uint8_t num_of_descriptors;
 	bool descriptors_queued;
 	bool busy;
+#if CONFIG_PM_DEVICE
+	struct dma_ch_backup_reg backup_reg;
+#endif /* CONFIG_PM_DEVICE */
 };
 
 struct dma_otrig {
@@ -68,6 +93,9 @@ struct dma_mcux_lpc_dma_data {
 	struct dma_otrig *otrig_array;
 	int8_t *channel_index;
 	uint8_t num_channels_used;
+#if CONFIG_PM_DEVICE
+	struct dma_backup_reg backup_reg;
+#endif /* CONFIG_PM_DEVICE */
 };
 
 struct k_spinlock configuring_otrigs;
@@ -948,6 +976,69 @@ static int dma_mcux_lpc_get_attribute(const struct device *dev, uint32_t type, u
 	return 0;
 }
 
+#if CONFIG_PM_DEVICE
+static void dma_mcux_lpc_backup_reg(const struct device *dev)
+{
+	struct dma_mcux_lpc_dma_data *dma_data = dev->data;
+	const struct dma_mcux_lpc_config *config = dev->config;
+	struct channel_data *p_channel_data;
+	uint32_t virtual_channel;
+	DMA_Type *dma_base = DEV_BASE(dev);
+
+	dma_data->backup_reg.enableset = dma_base->COMMON[0].ENABLESET;
+	dma_data->backup_reg.intenset  = dma_base->COMMON[0].INTENSET;
+
+	/* Only backup the used channels */
+	virtual_channel = 0;
+	for (uint32_t channel = 0; channel < config->num_of_channels; channel++) {
+		if (dma_data->channel_index[channel] != -1) {
+			p_channel_data = &dma_data->channel_data[virtual_channel];
+
+			p_channel_data->backup_reg.xfercfg = dma_base->CHANNEL[channel].XFERCFG;
+			p_channel_data->backup_reg.cfg     = dma_base->CHANNEL[channel].CFG;
+			virtual_channel++;
+		}
+	}
+}
+
+static void dma_mcux_lpc_restore_reg(const struct device *dev)
+{
+	struct dma_mcux_lpc_dma_data *dma_data = dev->data;
+	const struct dma_mcux_lpc_config *config = dev->config;
+	struct channel_data *p_channel_data;
+	uint32_t virtual_channel;
+	DMA_Type *dma_base = DEV_BASE(dev);
+
+	dma_base->COMMON[0].ENABLESET = dma_data->backup_reg.enableset;
+	dma_base->COMMON[0].INTENSET  = dma_data->backup_reg.intenset;
+
+	/* Only backup the used channels */
+	virtual_channel = 0;
+	for (uint32_t channel = 0; channel < config->num_of_channels; channel++) {
+		if (dma_data->channel_index[channel] != -1) {
+			p_channel_data = &dma_data->channel_data[virtual_channel];
+
+			dma_base->CHANNEL[channel].XFERCFG = p_channel_data->backup_reg.xfercfg;
+			dma_base->CHANNEL[channel].CFG     = p_channel_data->backup_reg.cfg;
+			virtual_channel++;
+		}
+	}
+}
+
+#else /* !CONFIG_PM_DEVICE */
+
+static inline static void dma_mcux_lpc_backup_reg(const struct device *dev)
+{
+	ARG_UNUSED(dev);
+}
+
+static inline static void dma_mcux_lpc_restore_reg(const struct device *dev)
+{
+	ARG_UNUSED(dev);
+}
+
+#endif /* CONFIG_PM_DEVICE */
+
 static int dma_mcux_lpc_pm_action(const struct device *dev, enum pm_device_action action)
 {
 	switch (action) {
@@ -956,9 +1047,11 @@ static int dma_mcux_lpc_pm_action(const struct device *dev, enum pm_device_actio
 	case PM_DEVICE_ACTION_SUSPEND:
 		break;
 	case PM_DEVICE_ACTION_TURN_OFF:
+		dma_mcux_lpc_backup_reg(dev);
 		break;
 	case PM_DEVICE_ACTION_TURN_ON:
 		DMA_Init(DEV_BASE(dev));
+		dma_mcux_lpc_restore_reg(dev);
 		break;
 	default:
 		return -ENOTSUP;