DMA: Split the APBH DMA init into block and channel init

This fixes the issue where mxs_dma_init() was called either twice or never,
without introducing any new init hooks.

The idea is to allow each and every device using the APBH DMA block to
configure and request only the channels it uses, instead of making it call init
for all the channels as is now.

The common DMA block init part, which only configures the block, is then called
from CPUs arch_cpu_init() call.

NOTE: This patch depends on:

	http://patchwork.ozlabs.org/patch/150957/Signed-off-by: NMarek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Tested-by: NFabio Estevam <fabio.estevam@freescale.com>

arch/arm/cpu/arm926ejs/mx28/mx28.c

@@ -30,6 +30,7 @@
 #include <asm/errno.h>
 #include <asm/io.h>
 #include <asm/arch/clock.h>
+#include <asm/arch/dma.h>
 #include <asm/arch/gpio.h>
 #include <asm/arch/iomux.h>
 #include <asm/arch/imx-regs.h>
@@ -172,6 +173,11 @@ int arch_cpu_init(void)
 	 */
 	mxs_gpio_init();
 
+#ifdef	CONFIG_APBH_DMA
+	/* Start APBH DMA */
+	mxs_dma_init();
+#endif
+
 	return 0;
 }
 #endif

arch/arm/include/asm/arch-mx28/dma.h

@@ -140,6 +140,8 @@ void mxs_dma_desc_free(struct mxs_dma_desc *);
 int mxs_dma_desc_append(int channel, struct mxs_dma_desc *pdesc);
 
 int mxs_dma_go(int chan);
-int mxs_dma_init(void);
+void mxs_dma_init(void);
+int mxs_dma_init_channel(int chan);
+int mxs_dma_release(int chan);
 
 #endif	/* __DMA_H__ */

drivers/dma/apbh_dma.c

@@ -316,7 +316,7 @@ static int mxs_dma_request(int channel)
  * The channel will NOT be released if it's marked "busy" (see
  * mxs_dma_enable()).
  */
-static int mxs_dma_release(int channel)
+int mxs_dma_release(int channel)
 {
 	struct mxs_dma_chan *pchan;
 	int ret;
@@ -552,12 +552,10 @@ int mxs_dma_go(int chan)
 /*
  * Initialize the DMA hardware
  */
-int mxs_dma_init(void)
+void mxs_dma_init(void)
 {
 	struct mx28_apbh_regs *apbh_regs =
 		(struct mx28_apbh_regs *)MXS_APBH_BASE;
-	struct mxs_dma_chan *pchan;
-	int ret, channel;
 
 	mx28_reset_block(&apbh_regs->hw_apbh_ctrl0_reg);
 
@@ -576,28 +574,26 @@ int mxs_dma_init(void)
 	writel(APBH_CTRL0_APB_BURST_EN,
 		&apbh_regs->hw_apbh_ctrl0_clr);
 #endif
+}
 
-	for (channel = 0; channel < MXS_MAX_DMA_CHANNELS; channel++) {
-		pchan = mxs_dma_channels + channel;
-		pchan->flags = MXS_DMA_FLAGS_VALID;
-
-		ret = mxs_dma_request(channel);
+int mxs_dma_init_channel(int channel)
+{
+	struct mxs_dma_chan *pchan;
+	int ret;
 
-		if (ret) {
-			printf("MXS DMA: Can't acquire DMA channel %i\n",
-				channel);
+	pchan = mxs_dma_channels + channel;
+	pchan->flags = MXS_DMA_FLAGS_VALID;
 
-			goto err;
-		}
+	ret = mxs_dma_request(channel);
 
-		mxs_dma_reset(channel);
-		mxs_dma_ack_irq(channel);
+	if (ret) {
+		printf("MXS DMA: Can't acquire DMA channel %i\n",
+			channel);
+		return ret;
 	}
 
-	return 0;
+	mxs_dma_reset(channel);
+	mxs_dma_ack_irq(channel);
 
-err:
-	while (--channel >= 0)
-		mxs_dma_release(channel);
-	return ret;
+	return 0;
 }

drivers/mmc/mxsmmc.c

@@ -338,6 +338,7 @@ int mxsmmc_initialize(bd_t *bis, int id, int (*wp)(int))
 		(struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
 	struct mmc *mmc = NULL;
 	struct mxsmmc_priv *priv = NULL;
+	int ret;
 
 	mmc = malloc(sizeof(struct mmc));
 	if (!mmc)
@@ -356,6 +357,10 @@ int mxsmmc_initialize(bd_t *bis, int id, int (*wp)(int))
 		return -ENOMEM;
 	}
 
+	ret = mxs_dma_init_channel(id);
+	if (ret)
+		return ret;
+
 	priv->mmc_is_wp = wp;
 	priv->id = id;
 	switch (id) {

drivers/mtd/nand/mxs_nand.c

@@ -1058,7 +1058,7 @@ int mxs_nand_init(struct mxs_nand_info *info)
 {
 	struct mx28_gpmi_regs *gpmi_regs =
 		(struct mx28_gpmi_regs *)MXS_GPMI_BASE;
-	int i = 0;
+	int i = 0, j;
 
 	info->desc = malloc(sizeof(struct mxs_dma_desc *) *
 				MXS_NAND_DMA_DESCRIPTOR_COUNT);
@@ -1073,7 +1073,11 @@ int mxs_nand_init(struct mxs_nand_info *info)
 	}
 
 	/* Init the DMA controller. */
-	mxs_dma_init();
+	for (j = MXS_DMA_CHANNEL_AHB_APBH_GPMI0;
+		j <= MXS_DMA_CHANNEL_AHB_APBH_GPMI7; j++) {
+		if (mxs_dma_init_channel(j))
+			goto err3;
+	}
 
 	/* Reset the GPMI block. */
 	mx28_reset_block(&gpmi_regs->hw_gpmi_ctrl0_reg);
@@ -1089,6 +1093,9 @@ int mxs_nand_init(struct mxs_nand_info *info)
 
 	return 0;
 
+err3:
+	for (--j; j >= 0; j--)
+		mxs_dma_release(j);
 err2:
 	free(info->desc);
 err1: