ARM: uniphier: support Debug UART

For ARM32 architecture, CONFIG_DEBUG_LL is available for early
low-level debugging (and actually UniPhier 32bit SoCs use it), but
ARM64 architecture does not support it.  Instead, CONFIG_DEBUG_UART
is available as an architecture-independent debug facility.

This commit supports it on all the UniPhier SoCs (including the new
ARMv8 SoCs), which is very useful for new SoC bringups.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

arch/arm/mach-uniphier/Makefile

@@ -28,5 +28,6 @@ obj-y += boot-mode/
 obj-y += dram/
 
 obj-$(CONFIG_MICRO_SUPPORT_CARD) += micro-support-card.o
+obj-$(CONFIG_DEBUG_UART_UNIPHIER) += debug-uart/
 
 obj-$(CONFIG_CPU_V7) += arm32/

arch/arm/mach-uniphier/debug-uart/Makefile

@@ -0,0 +1,17 @@
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+ifdef CONFIG_SPL_BUILD
+obj-$(CONFIG_ARCH_UNIPHIER_SLD3)	+= debug-uart-sld3.o
+obj-$(CONFIG_ARCH_UNIPHIER_LD4)		+= debug-uart-ld4.o
+obj-$(CONFIG_ARCH_UNIPHIER_PRO4)	+= debug-uart-pro4.o
+obj-$(CONFIG_ARCH_UNIPHIER_SLD8)	+= debug-uart-sld8.o
+obj-$(CONFIG_ARCH_UNIPHIER_PRO5)	+= debug-uart-pro5.o
+obj-$(CONFIG_ARCH_UNIPHIER_PXS2)	+= debug-uart-pxs2.o
+obj-$(CONFIG_ARCH_UNIPHIER_LD6B)	+= debug-uart-ld6b.o
+obj-$(CONFIG_ARCH_UNIPHIER_LD11)	+= debug-uart-ld20.o
+obj-$(CONFIG_ARCH_UNIPHIER_LD20)	+= debug-uart-ld20.o
+endif
+
+obj-y					+= debug-uart.o

arch/arm/mach-uniphier/debug-uart/debug-uart-ld20.c

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2016 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+
+#include "../sc64-regs.h"
+#include "../sg-regs.h"
+#include "debug-uart.h"
+
+#define UNIPHIER_LD20_UART_CLK		58820000
+
+unsigned int uniphier_ld20_debug_uart_init(void)
+{
+	u32 tmp;
+
+	sg_set_iectrl(54);		/* TXD0 */
+	sg_set_iectrl(58);		/* TXD1 */
+	sg_set_iectrl(90);		/* TXD2 */
+	sg_set_iectrl(94);		/* TXD3 */
+	sg_set_pinsel(54, 0, 8, 4);	/* TXD0 -> TXD0 */
+	sg_set_pinsel(58, 1, 8, 4);	/* SPITXD1 -> TXD1 */
+	sg_set_pinsel(90, 1, 8, 4);	/* PC0WE -> TXD2 */
+	sg_set_pinsel(94, 1, 8, 4);	/* PCD00 -> TXD3 */
+
+	tmp = readl(SC_CLKCTRL4);
+	tmp |= SC_CLKCTRL4_PERI;
+	writel(tmp, SC_CLKCTRL4);
+
+	return DIV_ROUND_CLOSEST(UNIPHIER_LD20_UART_CLK, 16 * CONFIG_BAUDRATE);
+}

arch/arm/mach-uniphier/debug-uart/debug-uart-ld4.c

@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2016 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <linux/kernel.h>
+
+#include "../sg-regs.h"
+#include "debug-uart.h"
+
+#define UNIPHIER_LD4_UART_CLK		36864000
+
+unsigned int uniphier_ld4_debug_uart_init(void)
+{
+	sg_set_iectrl(0);
+	sg_set_pinsel(88, 1, 8, 4);	/* HSDOUT6 -> TXD0 */
+
+	return DIV_ROUND_CLOSEST(UNIPHIER_LD4_UART_CLK, 16 * CONFIG_BAUDRATE);
+}

arch/arm/mach-uniphier/debug-uart/debug-uart-ld6b.c

@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2016 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+
+#include "../sc-regs.h"
+#include "../sg-regs.h"
+#include "debug-uart.h"
+
+#define UNIPHIER_LD6B_UART_CLK		88888888
+
+unsigned int uniphier_ld6b_debug_uart_init(void)
+{
+	u32 tmp;
+
+	sg_set_iectrl(0);
+	sg_set_pinsel(135, 3, 8, 4);	/* PORT10 -> TXD0 */
+	sg_set_pinsel(115, 0, 8, 4);	/* TXD1 -> TXD1 */
+	sg_set_pinsel(113, 2, 8, 4);	/* SBO0 -> TXD2 */
+
+	tmp = readl(SC_CLKCTRL);
+	tmp |= SC_CLKCTRL_CEN_PERI;
+	writel(tmp, SC_CLKCTRL);
+
+	return DIV_ROUND_CLOSEST(UNIPHIER_LD6B_UART_CLK, 16 * CONFIG_BAUDRATE);
+}

arch/arm/mach-uniphier/debug-uart/debug-uart-pro4.c

@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2016 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+
+#include "../sc-regs.h"
+#include "../sg-regs.h"
+#include "debug-uart.h"
+
+#define UNIPHIER_PRO4_UART_CLK		73728000
+
+unsigned int uniphier_pro4_debug_uart_init(void)
+{
+	u32 tmp;
+
+	sg_set_iectrl(0);
+	sg_set_pinsel(128, 0, 4, 8);	/* TXD0 -> TXD0 */
+
+	writel(1, SG_LOADPINCTRL);
+
+	tmp = readl(SC_CLKCTRL);
+	tmp |= SC_CLKCTRL_CEN_PERI;
+	writel(tmp, SC_CLKCTRL);
+
+	return DIV_ROUND_CLOSEST(UNIPHIER_PRO4_UART_CLK, 16 * CONFIG_BAUDRATE);
+}

arch/arm/mach-uniphier/debug-uart/debug-uart-pro5.c

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2016 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+
+#include "../sc-regs.h"
+#include "../sg-regs.h"
+#include "debug-uart.h"
+
+#define UNIPHIER_PRO5_UART_CLK		73728000
+
+unsigned int uniphier_pro5_debug_uart_init(void)
+{
+	u32 tmp;
+
+	sg_set_iectrl(0);
+	sg_set_pinsel(47, 0, 4, 8);	/* TXD0 -> TXD0 */
+	sg_set_pinsel(49, 0, 4, 8);	/* TXD1 -> TXD1 */
+	sg_set_pinsel(51, 0, 4, 8);	/* TXD2 -> TXD2 */
+	sg_set_pinsel(53, 0, 4, 8);	/* TXD3 -> TXD3 */
+
+	writel(1, SG_LOADPINCTRL);
+
+	tmp = readl(SC_CLKCTRL);
+	tmp |= SC_CLKCTRL_CEN_PERI;
+	writel(tmp, SC_CLKCTRL);
+
+	return DIV_ROUND_CLOSEST(UNIPHIER_PRO5_UART_CLK, 16 * CONFIG_BAUDRATE);
+}

arch/arm/mach-uniphier/debug-uart/debug-uart-pxs2.c

@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2016 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+
+#include "../sc-regs.h"
+#include "../sg-regs.h"
+#include "debug-uart.h"
+
+#define UNIPHIER_PXS2_UART_CLK		88888888
+
+unsigned int uniphier_pxs2_debug_uart_init(void)
+{
+	u32 tmp;
+
+	sg_set_iectrl(0);
+	sg_set_pinsel(217, 8, 8, 4);	/* TXD0 -> TXD0 */
+	sg_set_pinsel(115, 8, 8, 4);	/* TXD1 -> TXD1 */
+	sg_set_pinsel(113, 8, 8, 4);	/* TXD2 -> TXD2 */
+	sg_set_pinsel(219, 8, 8, 4);	/* TXD3 -> TXD3 */
+
+	tmp = readl(SC_CLKCTRL);
+	tmp |= SC_CLKCTRL_CEN_PERI;
+	writel(tmp, SC_CLKCTRL);
+
+	return DIV_ROUND_CLOSEST(UNIPHIER_PXS2_UART_CLK, 16 * CONFIG_BAUDRATE);
+}

arch/arm/mach-uniphier/debug-uart/debug-uart-sld3.c

@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2016 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+
+#include "../bcu/bcu-regs.h"
+#include "../sc-regs.h"
+#include "../sg-regs.h"
+#include "debug-uart.h"
+
+#define UNIPHIER_SLD3_UART_CLK		36864000
+
+unsigned int uniphier_sld3_debug_uart_init(void)
+{
+	u32 tmp;
+
+	sg_set_pinsel(64, 1, 4, 4);	/* TXD0 -> TXD0 */
+
+	writel(0x24440000, BCSCR5);
+
+	tmp = readl(SC_CLKCTRL);
+	tmp |= SC_CLKCTRL_CEN_PERI;
+	writel(tmp, SC_CLKCTRL);
+
+	return DIV_ROUND_CLOSEST(UNIPHIER_SLD3_UART_CLK, 16 * CONFIG_BAUDRATE);
+}

arch/arm/mach-uniphier/debug-uart/debug-uart-sld8.c

@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2016 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <linux/kernel.h>
+
+#include "../sg-regs.h"
+#include "debug-uart.h"
+
+#define UNIPHIER_SLD8_UART_CLK		80000000
+
+unsigned int uniphier_sld8_debug_uart_init(void)
+{
+	sg_set_iectrl(0);
+	sg_set_pinsel(70, 3, 8, 4);	/* HSDOUT6 -> TXD0 */
+
+	return DIV_ROUND_CLOSEST(UNIPHIER_SLD8_UART_CLK, 16 * CONFIG_BAUDRATE);
+}

arch/arm/mach-uniphier/debug-uart/debug-uart.c

@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2016 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <debug_uart.h>
+#include <linux/io.h>
+#include <linux/serial_reg.h>
+
+#include "../soc-info.h"
+#include "debug-uart.h"
+
+#define UNIPHIER_UART_TX		0x00
+#define UNIPHIER_UART_LCR_MCR		0x10
+#define UNIPHIER_UART_LSR		0x14
+#define UNIPHIER_UART_LDR		0x24
+
+static void _debug_uart_putc(int c)
+{
+	void __iomem *base = (void __iomem *)CONFIG_DEBUG_UART_BASE;
+
+	while (!(readl(base + UNIPHIER_UART_LSR) & UART_LSR_THRE))
+		;
+
+	writel(c, base + UNIPHIER_UART_TX);
+}
+
+void _debug_uart_init(void)
+{
+	void __iomem *base = (void __iomem *)CONFIG_DEBUG_UART_BASE;
+	unsigned int divisor;
+
+	switch (uniphier_get_soc_type()) {
+#if defined(CONFIG_ARCH_UNIPHIER_SLD3)
+	case SOC_UNIPHIER_SLD3:
+		divisor = uniphier_sld3_debug_uart_init();
+		break;
+#endif
+#if defined(CONFIG_ARCH_UNIPHIER_LD4)
+	case SOC_UNIPHIER_LD4:
+		divisor = uniphier_ld4_debug_uart_init();
+		break;
+#endif
+#if defined(CONFIG_ARCH_UNIPHIER_PRO4)
+	case SOC_UNIPHIER_PRO4:
+		divisor = uniphier_pro4_debug_uart_init();
+		break;
+#endif
+#if defined(CONFIG_ARCH_UNIPHIER_SLD8)
+	case SOC_UNIPHIER_SLD8:
+		divisor = uniphier_sld8_debug_uart_init();
+		break;
+#endif
+#if defined(CONFIG_ARCH_UNIPHIER_PRO5)
+	case SOC_UNIPHIER_PRO5:
+		divisor = uniphier_pro5_debug_uart_init();
+		break;
+#endif
+#if defined(CONFIG_ARCH_UNIPHIER_PXS2)
+	case SOC_UNIPHIER_PXS2:
+		divisor = uniphier_pxs2_debug_uart_init();
+		break;
+#endif
+#if defined(CONFIG_ARCH_UNIPHIER_LD6B)
+	case SOC_UNIPHIER_LD6B:
+		divisor = uniphier_ld6b_debug_uart_init();
+		break;
+#endif
+#if defined(CONFIG_ARCH_UNIPHIER_LD11) || defined(CONFIG_ARCH_UNIPHIER_LD20)
+	case SOC_UNIPHIER_LD11:
+	case SOC_UNIPHIER_LD20:
+		divisor = uniphier_ld20_debug_uart_init();
+		break;
+#endif
+	default:
+		return;
+	}
+
+	writel(UART_LCR_WLEN8 << 8, base + UNIPHIER_UART_LCR_MCR);
+
+	writel(divisor, base + UNIPHIER_UART_LDR);
+}
+DEBUG_UART_FUNCS

arch/arm/mach-uniphier/debug-uart/debug-uart.h

@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2016 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _MACH_DEBUG_UART_H
+#define _MACH_DEBUG_UART_H
+
+unsigned int uniphier_sld3_debug_uart_init(void);
+unsigned int uniphier_ld4_debug_uart_init(void);
+unsigned int uniphier_pro4_debug_uart_init(void);
+unsigned int uniphier_sld8_debug_uart_init(void);
+unsigned int uniphier_pro5_debug_uart_init(void);
+unsigned int uniphier_pxs2_debug_uart_init(void);
+unsigned int uniphier_ld6b_debug_uart_init(void);
+unsigned int uniphier_ld11_debug_uart_init(void);
+unsigned int uniphier_ld20_debug_uart_init(void);
+
+#endif /* _MACH_DEBUG_UART_H */

arch/arm/mach-uniphier/init/init.c

@@ -5,6 +5,7 @@
  */
 
 #include <common.h>
+#include <debug_uart.h>
 #include <spl.h>
 
 #include "../init.h"
@@ -14,6 +15,10 @@ void spl_board_init(void)
 {
 	const struct uniphier_board_data *param;
 
+#ifdef CONFIG_DEBUG_UART
+	debug_uart_init();
+#endif
+
 	param = uniphier_get_board_param();
 	if (!param)
 		hang();

drivers/serial/Kconfig

@@ -169,6 +169,15 @@ config DEBUG_UART_PIC32
 	  will need to provide parameters to make this work. The driver will
 	  be available until the real driver model serial is running.
 
+config DEBUG_UART_UNIPHIER
+	bool "UniPhier on-chip UART"
+	depends on ARCH_UNIPHIER
+	help
+	  Select this to enable a debug UART using the UniPhier on-chip UART.
+	  You will need to provide DEBUG_UART_BASE to make this work.  The
+	  driver will be available until the real driver-model serial is
+	  running.
+
 endchoice
 
 config DEBUG_UART_BASE