Blackfin: bf54x: add kconfig for UART2/3 DMA channel assignments

The BF54x lacks dedicated DMA channels for the UART peripherals and need
to be muxed between others.  So add a kconfig option so people can select
which channels the UARTs will use so they can pick between SPORTs and the
less commonly used EPPI/PIXC peripherals.

Signed-off-by: steven miao <realmz6@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

arch/blackfin/kernel/bfin_dma_5xx.c

@@ -84,6 +84,24 @@ static int __init proc_dma_init(void)
 late_initcall(proc_dma_init);
 #endif
 
+static void set_dma_peripheral_map(unsigned int channel, const char *device_id)
+{
+#ifdef CONFIG_BF54x
+	unsigned int per_map;
+
+	switch (channel) {
+		case CH_UART2_RX: per_map = 0xC << 12; break;
+		case CH_UART2_TX: per_map = 0xD << 12; break;
+		case CH_UART3_RX: per_map = 0xE << 12; break;
+		case CH_UART3_TX: per_map = 0xF << 12; break;
+		default:          return;
+	}
+
+	if (strncmp(device_id, "BFIN_UART", 9) == 0)
+		dma_ch[channel].regs->peripheral_map = per_map;
+#endif
+}
+
 /**
  *	request_dma - request a DMA channel
  *
@@ -111,19 +129,7 @@ int request_dma(unsigned int channel, const char *device_id)
 		return -EBUSY;
 	}
 
-#ifdef CONFIG_BF54x
-	if (channel >= CH_UART2_RX && channel <= CH_UART3_TX) {
-		unsigned int per_map;
-		per_map = dma_ch[channel].regs->peripheral_map & 0xFFF;
-		if (strncmp(device_id, "BFIN_UART", 9) == 0)
-			dma_ch[channel].regs->peripheral_map = per_map |
-				((channel - CH_UART2_RX + 0xC)<<12);
-		else
-			dma_ch[channel].regs->peripheral_map = per_map |
-				((channel - CH_UART2_RX + 0x6)<<12);
-	}
-#endif
-
+	set_dma_peripheral_map(channel, device_id);
 	dma_ch[channel].device_id = device_id;
 	dma_ch[channel].irq = 0;
 

arch/blackfin/mach-bf548/Kconfig

@@ -42,6 +42,65 @@ config BF548_ATAPI_ALTERNATIVE_PORT
 	  async address or GPIO port F and G. Select y to route it
 	  to GPIO.
 
+choice
+	prompt "UART2 DMA channel selection"
+	depends on SERIAL_BFIN_UART2
+	default UART2_DMA_RX_ON_DMA18
+	help
+		UART2 DMA channel selection
+		RX -> DMA18
+		TX -> DMA19
+		or
+		RX -> DMA13
+		TX -> DMA14
+
+config UART2_DMA_RX_ON_DMA18
+	bool "UART2 DMA RX -> DMA18 TX -> DMA19"
+	help
+		UART2 DMA channel assignment
+		RX -> DMA18
+		TX -> DMA19
+		use SPORT2 default DMA channel
+
+config UART2_DMA_RX_ON_DMA13
+	bool "UART2 DMA RX -> DMA13 TX -> DMA14"
+	help
+		UART2 DMA channel assignment
+		RX -> DMA13
+		TX -> DMA14
+		use EPPI1 EPPI2 default DMA channel
+endchoice
+
+choice
+	prompt "UART3 DMA channel selection"
+	depends on SERIAL_BFIN_UART3
+	default UART3_DMA_RX_ON_DMA20
+	help
+		UART3 DMA channel selection
+		RX -> DMA20
+		TX -> DMA21
+		or
+		RX -> DMA15
+		TX -> DMA16
+
+config UART3_DMA_RX_ON_DMA20
+	bool "UART3 DMA RX -> DMA20 TX -> DMA21"
+	help
+		UART3 DMA channel assignment
+		RX -> DMA20
+		TX -> DMA21
+		use SPORT3 default DMA channel
+
+config UART3_DMA_RX_ON_DMA15
+	bool "UART3 DMA RX -> DMA15 TX -> DMA16"
+	help
+		UART3 DMA channel assignment
+		RX -> DMA15
+		TX -> DMA16
+		use PIXC default DMA channel
+
+endchoice
+
 comment "Interrupt Priority Assignment"
 menu "Priority"
 

arch/blackfin/mach-bf548/include/mach/dma.h

@@ -27,17 +27,37 @@
 #define CH_PIXC_OVERLAY		16
 #define CH_PIXC_OUTPUT		17
 #define CH_SPORT2_RX		18
-#define CH_UART2_RX		18
 #define CH_SPORT2_TX		19
-#define CH_UART2_TX		19
 #define CH_SPORT3_RX		20
-#define CH_UART3_RX		20
 #define CH_SPORT3_TX		21
-#define CH_UART3_TX		21
 #define CH_SDH			22
 #define CH_NFC			22
 #define CH_SPI2			23
 
+#if defined(CONFIG_UART2_DMA_RX_ON_DMA13)
+#define CH_UART2_RX		13
+#define IRQ_UART2_RX		BFIN_IRQ(37)	/* UART2 RX USE EPP1 (DMA13) Interrupt */
+#define CH_UART2_TX		14
+#define IRQ_UART2_TX		BFIN_IRQ(38)	/* UART2 RX USE EPP1 (DMA14) Interrupt */
+#else						/* Default USE SPORT2's DMA Channel */
+#define CH_UART2_RX		18
+#define IRQ_UART2_RX		BFIN_IRQ(33)	/* UART2 RX (DMA18) Interrupt */
+#define CH_UART2_TX		19
+#define IRQ_UART2_TX		BFIN_IRQ(34)	/* UART2 TX (DMA19) Interrupt */
+#endif
+
+#if defined(CONFIG_UART3_DMA_RX_ON_DMA15)
+#define CH_UART3_RX		15
+#define IRQ_UART3_RX		BFIN_IRQ(64)	/* UART3 RX USE PIXC IN0 (DMA15) Interrupt */
+#define CH_UART3_TX		16
+#define IRQ_UART3_TX		BFIN_IRQ(65)	/* UART3 TX USE PIXC IN1 (DMA16) Interrupt */
+#else						/* Default USE SPORT3's DMA Channel */
+#define CH_UART3_RX		20
+#define IRQ_UART3_RX		BFIN_IRQ(35)	/* UART3 RX (DMA20) Interrupt */
+#define CH_UART3_TX		21
+#define IRQ_UART3_TX		BFIN_IRQ(36)	/* UART3 TX (DMA21) Interrupt */
+#endif
+
 #define CH_MEM_STREAM0_DEST	24
 #define CH_MEM_STREAM0_SRC	25
 #define CH_MEM_STREAM1_DEST	26

arch/blackfin/mach-bf548/include/mach/irq.h

@@ -74,13 +74,9 @@ Events         (highest priority)  EMU         0
 #define IRQ_UART2_ERROR		BFIN_IRQ(31)	/* UART2 Status (Error) Interrupt */
 #define IRQ_CAN0_ERROR		BFIN_IRQ(32)	/* CAN0 Status (Error) Interrupt */
 #define IRQ_SPORT2_RX		BFIN_IRQ(33)	/* SPORT2 RX (DMA18) Interrupt */
-#define IRQ_UART2_RX		BFIN_IRQ(33)	/* UART2 RX (DMA18) Interrupt */
 #define IRQ_SPORT2_TX		BFIN_IRQ(34)	/* SPORT2 TX (DMA19) Interrupt */
-#define IRQ_UART2_TX		BFIN_IRQ(34)	/* UART2 TX (DMA19) Interrupt */
 #define IRQ_SPORT3_RX		BFIN_IRQ(35)	/* SPORT3 RX (DMA20) Interrupt */
-#define IRQ_UART3_RX		BFIN_IRQ(35)	/* UART3 RX (DMA20) Interrupt */
 #define IRQ_SPORT3_TX		BFIN_IRQ(36)	/* SPORT3 TX (DMA21) Interrupt */
-#define IRQ_UART3_TX		BFIN_IRQ(36)	/* UART3 TX (DMA21) Interrupt */
 #define IRQ_EPPI1		BFIN_IRQ(37)	/* EPP1 (DMA13) Interrupt */
 #define IRQ_EPPI2		BFIN_IRQ(38)	/* EPP2 (DMA14) Interrupt */
 #define IRQ_SPI1		BFIN_IRQ(39)	/* SPI1 (DMA5) Interrupt */