diff --git a/arch/arm/include/asm/arch-mxs/dma.h b/arch/arm/include/asm/arch-mxs/dma.h
index a0a0ea5..1ac8696 100644
--- a/arch/arm/include/asm/arch-mxs/dma.h
+++ b/arch/arm/include/asm/arch-mxs/dma.h
@@ -40,6 +40,19 @@
 /*
  * MXS DMA channels
  */
+#if defined(CONFIG_MX23)
+enum {
+	MXS_DMA_CHANNEL_AHB_APBH_LCDIF = 0,
+	MXS_DMA_CHANNEL_AHB_APBH_SSP0,
+	MXS_DMA_CHANNEL_AHB_APBH_SSP1,
+	MXS_DMA_CHANNEL_AHB_APBH_RESERVED0,
+	MXS_DMA_CHANNEL_AHB_APBH_GPMI0,
+	MXS_DMA_CHANNEL_AHB_APBH_GPMI1,
+	MXS_DMA_CHANNEL_AHB_APBH_GPMI2,
+	MXS_DMA_CHANNEL_AHB_APBH_GPMI3,
+	MXS_MAX_DMA_CHANNELS,
+};
+#elif defined(CONFIG_MX28)
 enum {
 	MXS_DMA_CHANNEL_AHB_APBH_SSP0 = 0,
 	MXS_DMA_CHANNEL_AHB_APBH_SSP1,
@@ -53,9 +66,13 @@ enum {
 	MXS_DMA_CHANNEL_AHB_APBH_GPMI5,
 	MXS_DMA_CHANNEL_AHB_APBH_GPMI6,
 	MXS_DMA_CHANNEL_AHB_APBH_GPMI7,
-	MXS_DMA_CHANNEL_AHB_APBH_SSP,
+	MXS_DMA_CHANNEL_AHB_APBH_HSADC,
+	MXS_DMA_CHANNEL_AHB_APBH_LCDIF,
+	MXS_DMA_CHANNEL_AHB_APBH_RESERVED0,
+	MXS_DMA_CHANNEL_AHB_APBH_RESERVED1,
 	MXS_MAX_DMA_CHANNELS,
 };
+#endif
 
 /*
  * MXS DMA hardware command.
diff --git a/arch/arm/include/asm/arch-mxs/regs-ssp.h b/arch/arm/include/asm/arch-mxs/regs-ssp.h
index 9b30f56..5920f9b 100644
--- a/arch/arm/include/asm/arch-mxs/regs-ssp.h
+++ b/arch/arm/include/asm/arch-mxs/regs-ssp.h
@@ -74,6 +74,32 @@ struct mxs_ssp_regs {
 };
 #endif
 
+static inline int mxs_ssp_bus_id_valid(int bus)
+{
+#if defined(CONFIG_MX23)
+	const unsigned int mxs_ssp_chan_count = 2;
+#elif defined(CONFIG_MX28)
+	const unsigned int mxs_ssp_chan_count = 4;
+#endif
+
+	if (bus >= mxs_ssp_chan_count)
+		return 0;
+
+	if (bus < 0)
+		return 0;
+
+	return 1;
+}
+
+static inline int mxs_ssp_clock_by_bus(unsigned int clock)
+{
+#if defined(CONFIG_MX23)
+	return 0;
+#elif defined(CONFIG_MX28)
+	return clock;
+#endif
+}
+
 static inline struct mxs_ssp_regs *mxs_ssp_regs_by_bus(unsigned int port)
 {
 	switch (port) {
diff --git a/drivers/mmc/mxsmmc.c b/drivers/mmc/mxsmmc.c
index ae0f378..939d549 100644
--- a/drivers/mmc/mxsmmc.c
+++ b/drivers/mmc/mxsmmc.c
@@ -53,12 +53,6 @@ struct mxsmmc_priv {
 	struct mxs_dma_desc	*desc;
 };
 
-#if defined(CONFIG_MX23)
-static const unsigned int mxsmmc_id_offset = 1;
-#elif defined(CONFIG_MX28)
-static const unsigned int mxsmmc_id_offset = 0;
-#endif
-
 #define	MXSMMC_MAX_TIMEOUT	10000
 #define MXSMMC_SMALL_TRANSFER	512
 
@@ -137,7 +131,7 @@ static int mxsmmc_send_cmd_dma(struct mxsmmc_priv *priv, struct mmc_data *data)
 	priv->desc->cmd.data |= MXS_DMA_DESC_IRQ | MXS_DMA_DESC_DEC_SEM |
 				(data_count << MXS_DMA_DESC_BYTES_OFFSET);
 
-	dmach = MXS_DMA_CHANNEL_AHB_APBH_SSP0 + priv->id + mxsmmc_id_offset;
+	dmach = MXS_DMA_CHANNEL_AHB_APBH_SSP0 + priv->id;
 	mxs_dma_desc_append(dmach, priv->desc);
 	if (mxs_dma_go(dmach)) {
 		bounce_buffer_stop(&bbstate);
@@ -390,15 +384,9 @@ int mxsmmc_initialize(bd_t *bis, int id, int (*wp)(int), int (*cd)(int))
 	struct mmc *mmc = NULL;
 	struct mxsmmc_priv *priv = NULL;
 	int ret;
-#if defined(CONFIG_MX23)
-	const unsigned int mxsmmc_max_id = 2;
-	const unsigned int mxsmmc_clk_id = 0;
-#elif defined(CONFIG_MX28)
-	const unsigned int mxsmmc_max_id = 4;
-	const unsigned int mxsmmc_clk_id = id;
-#endif
+	const unsigned int mxsmmc_clk_id = mxs_ssp_clock_by_bus(id);
 
-	if (id >= mxsmmc_max_id)
+	if (mxs_ssp_bus_id_valid(id))
 		return -ENODEV;
 
 	mmc = malloc(sizeof(struct mmc));
@@ -418,7 +406,7 @@ int mxsmmc_initialize(bd_t *bis, int id, int (*wp)(int), int (*cd)(int))
 		return -ENOMEM;
 	}
 
-	ret = mxs_dma_init_channel(id + mxsmmc_id_offset);
+	ret = mxs_dma_init_channel(MXS_DMA_CHANNEL_AHB_APBH_SSP0 + id);
 	if (ret)
 		return ret;
 
diff --git a/drivers/spi/mxs_spi.c b/drivers/spi/mxs_spi.c
index bb865b7..5f2fd18 100644
--- a/drivers/spi/mxs_spi.c
+++ b/drivers/spi/mxs_spi.c
@@ -70,7 +70,7 @@ void spi_init(void)
 int spi_cs_is_valid(unsigned int bus, unsigned int cs)
 {
 	/* MXS SPI: 4 ports and 3 chip selects maximum */
-	if (bus > 3 || cs > 2)
+	if (mxs_ssp_bus_id_valid(bus) || cs > 2)
 		return 0;
 	else
 		return 1;
@@ -92,7 +92,7 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
 	if (!mxs_slave)
 		return NULL;
 
-	if (mxs_dma_init_channel(bus))
+	if (mxs_dma_init_channel(MXS_DMA_CHANNEL_AHB_APBH_SSP0 + bus))
 		goto err_init;
 
 	mxs_slave->slave.bus = bus;