ARM: shmobile: Add early debugging support using SCIF(A)

Add serial port debug macros for the SCIF(A) serial ports.
This includes all supported shmobile SoCs, except for EMEV2.

The configuration logic (both Kconfig and #ifdef) is more complicated than
one would expect, for several reasons:
1. Not all SoCs have the same serial devices, and they're not always
at the same addresses.
2. There are two different types: SCIF and SCIFA. Fortunately they can
easily be distinguished by physical address.
3. Not all boards use the same serial port for the console.
The defaults correspond to the boards that are supported in
mainline. If you want to use a different serial port, just change
the value of CONFIG_DEBUG_UART_PHYS, and the rest will auto-adapt.
4. debug_ll_io_init() maps the SCIF(A) registers to a fixed virtual
address. 0xfdxxxxxx was chosen, as it should lie below VMALLOC_END
= 0xff000000, and must not conflict with the 2 MiB reserved region
at PCI_IO_VIRT_BASE = 0xfee00000.
- On SoCs not using the legacy machine_desc.map_io(),
debug_ll_io_init() is called by the ARM core code.
- On SoCs using the legacy machine_desc.map_io(),
debug_ll_io_init() must be called explicitly. Calls are added
for r8a7740, r8a7779, sh7372, and sh73a0.

This was derived from the r8a7790 version by Laurent Pinchart.

Signed-off-by: Geert Uytterhoeven <[e-mail]>
Acked-by: Laurent Pinchart <[e-mail]>
Acked-by: Arnd Bergmann <[e-mail]>
Tested-by: Simon Horman <[e-mail]>
Signed-off-by: Simon Horman <[e-mail]>

MAINTAINERS

···
 F:	arch/arm/configs/mackerel_defconfig
 F:	arch/arm/configs/marzen_defconfig
 F:	arch/arm/configs/shmobile_defconfig
+F:	arch/arm/include/debug/renesas-scif.S
 F:	arch/arm/mach-shmobile/
 F:	drivers/sh/
 

arch/arm/Kconfig.debug

···
 		  Say Y here if you want kernel low-level debugging support
 		  on Rockchip RK32xx based platforms.
 
+	config DEBUG_R7S72100_SCIF2
+		bool "Kernel low-level debugging messages via SCIF2 on R7S72100"
+		depends on ARCH_R7S72100
+		help
+		  Say Y here if you want kernel low-level debugging support
+		  via SCIF2 on Renesas RZ/A1H (R7S72100).
+
+	config DEBUG_RCAR_GEN1_SCIF0
+		bool "Kernel low-level debugging messages via SCIF0 on R8A7778"
+		depends on ARCH_R8A7778
+		help
+		  Say Y here if you want kernel low-level debugging support
+		  via SCIF0 on Renesas R-Car M1A (R8A7778).
+
+	config DEBUG_RCAR_GEN1_SCIF2
+		bool "Kernel low-level debugging messages via SCIF2 on R8A7779"
+		depends on ARCH_R8A7779
+		help
+		  Say Y here if you want kernel low-level debugging support
+		  via SCIF2 on Renesas R-Car H1 (R8A7779).
+
+	config DEBUG_RCAR_GEN2_SCIF0
+		bool "Kernel low-level debugging messages via SCIF0 on R8A7790/R8A7791/R8A7793)"
+		depends on ARCH_R8A7790 || ARCH_R8A7791 || ARCH_R8A7793
+		help
+		  Say Y here if you want kernel low-level debugging support
+		  via SCIF0 on Renesas R-Car H2 (R8A7790), M2-W (R8A7791), or
+		  M2-N (R8A7793).
+
+	config DEBUG_RCAR_GEN2_SCIF2
+		bool "Kernel low-level debugging messages via SCIF2 on R8A7794"
+		depends on ARCH_R8A7794
+		help
+		  Say Y here if you want kernel low-level debugging support
+		  via SCIF2 on Renesas R-Car E2 (R8A7794).
+
+	config DEBUG_RMOBILE_SCIFA0
+		bool "Kernel low-level debugging messages via SCIFA0 on R8A73A4/SH7372"
+		depends on ARCH_R8A73A4 || ARCH_SH7372
+		help
+		  Say Y here if you want kernel low-level debugging support
+		  via SCIFA0 on Renesas R-Mobile APE6 (R8A73A4) or SH-Mobile
+		  AP4 (SH7372).
+
+	config DEBUG_RMOBILE_SCIFA1
+		bool "Kernel low-level debugging messages via SCIFA1 on R8A7740"
+		depends on ARCH_R8A7740
+		help
+		  Say Y here if you want kernel low-level debugging support
+		  via SCIFA1 on Renesas R-Mobile A1 (R8A7740).
+
+	config DEBUG_RMOBILE_SCIFA4
+		bool "Kernel low-level debugging messages via SCIFA4 on SH73A0"
+		depends on ARCH_SH73A0
+		help
+		  Say Y here if you want kernel low-level debugging support
+		  via SCIFA4 on Renesas SH-Mobile AG5 (SH73A0).
+
 	config DEBUG_S3C_UART0
 		depends on PLAT_SAMSUNG
 		select DEBUG_EXYNOS_UART if ARCH_EXYNOS
···
 				 DEBUG_IMX6SX_UART
 	default "debug/msm.S" if DEBUG_MSM_UART || DEBUG_QCOM_UARTDM
 	default "debug/omap2plus.S" if DEBUG_OMAP2PLUS_UART
+	default "debug/renesas-scif.S" if DEBUG_R7S72100_SCIF2
+	default "debug/renesas-scif.S" if DEBUG_RCAR_GEN1_SCIF0
+	default "debug/renesas-scif.S" if DEBUG_RCAR_GEN1_SCIF2
+	default "debug/renesas-scif.S" if DEBUG_RCAR_GEN2_SCIF0
+	default "debug/renesas-scif.S" if DEBUG_RCAR_GEN2_SCIF2
+	default "debug/renesas-scif.S" if DEBUG_RMOBILE_SCIFA0
+	default "debug/renesas-scif.S" if DEBUG_RMOBILE_SCIFA1
+	default "debug/renesas-scif.S" if DEBUG_RMOBILE_SCIFA4
 	default "debug/s3c24xx.S" if DEBUG_S3C24XX_UART
 	default "debug/s5pv210.S" if DEBUG_S5PV210_UART
 	default "debug/sirf.S" if DEBUG_SIRFPRIMA2_UART1 || DEBUG_SIRFMARCO_UART1
···
 	default 0xd4018000 if DEBUG_MMP_UART3
 	default 0xe0000000 if ARCH_SPEAR13XX
 	default 0xe4007000 if DEBUG_HIP04_UART
+	default 0xe6c40000 if DEBUG_RMOBILE_SCIFA0
+	default 0xe6c50000 if DEBUG_RMOBILE_SCIFA1
+	default 0xe6c80000 if DEBUG_RMOBILE_SCIFA4
+	default 0xe6e58000 if DEBUG_RCAR_GEN2_SCIF2
+	default 0xe6e60000 if DEBUG_RCAR_GEN2_SCIF0
+	default 0xe8008000 if DEBUG_R7S72100_SCIF2
 	default 0xf0000be0 if ARCH_EBSA110
 	default 0xf1012000 if DEBUG_MVEBU_UART_ALTERNATE
 	default 0xf1012000 if ARCH_DOVE || ARCH_MV78XX0 || \
···
 	default 0xff690000 if DEBUG_RK32_UART2
 	default 0xffc02000 if DEBUG_SOCFPGA_UART
 	default 0xffd82340 if ARCH_IOP13XX
+	default 0xffe40000 if DEBUG_RCAR_GEN1_SCIF0
+	default 0xffe42000 if DEBUG_RCAR_GEN1_SCIF2
 	default 0xfff36000 if DEBUG_HIGHBANK_UART
 	default 0xfffe8600 if DEBUG_UART_BCM63XX
 	default 0xfffff700 if ARCH_IOP33X
 	depends on DEBUG_LL_UART_8250 || DEBUG_LL_UART_PL01X || \
 		DEBUG_LL_UART_EFM32 || \
 		DEBUG_UART_8250 || DEBUG_UART_PL01X || DEBUG_MESON_UARTAO || \
-		DEBUG_MSM_UART || DEBUG_QCOM_UARTDM || DEBUG_S3C24XX_UART || \
+		DEBUG_MSM_UART || DEBUG_QCOM_UARTDM || DEBUG_R7S72100_SCIF2 || \
+		DEBUG_RCAR_GEN1_SCIF0 || DEBUG_RCAR_GEN1_SCIF2 || \
+		DEBUG_RCAR_GEN2_SCIF0 || DEBUG_RCAR_GEN2_SCIF2 || \
+		DEBUG_RMOBILE_SCIFA0 || DEBUG_RMOBILE_SCIFA1 || \
+		DEBUG_RMOBILE_SCIFA4 || DEBUG_S3C24XX_UART || \
 		DEBUG_UART_BCM63XX
 
 config DEBUG_UART_VIRT

arch/arm/include/debug/renesas-scif.S

···
+/*
+ * Renesas SCIF(A) debugging macro include header
+ *
+ * Based on r8a7790.S
+ *
+ * Copyright (C) 2012-2013 Renesas Electronics Corporation
+ * Copyright (C) 1994-1999 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#define SCIF_PHYS	CONFIG_DEBUG_UART_PHYS
+#define SCIF_VIRT	((SCIF_PHYS & 0x00ffffff) | 0xfd000000)
+
+#if CONFIG_DEBUG_UART_PHYS < 0xe6e00000
+/* SCIFA */
+#define FTDR		0x20
+#define FSR		0x14
+#else
+/* SCIF */
+#define FTDR		0x0c
+#define FSR		0x10
+#endif
+
+#define TDFE	(1 << 5)
+#define TEND	(1 << 6)
+
+	.macro	addruart, rp, rv, tmp
+	ldr	\rp, =SCIF_PHYS
+	ldr	\rv, =SCIF_VIRT
+	.endm
+
+	.macro	waituart, rd, rx
+1001:	ldrh	\rd, [\rx, #FSR]
+	tst	\rd, #TDFE
+	beq	1001b
+	.endm
+
+	.macro	senduart, rd, rx
+	strb	\rd, [\rx, #FTDR]
+	ldrh	\rd, [\rx, #FSR]
+	bic	\rd, \rd, #TEND
+	strh	\rd, [\rx, #FSR]
+	.endm
+
+	.macro	busyuart, rd, rx
+1001:	ldrh	\rd, [\rx, #FSR]
+	tst	\rd, #TEND
+	beq	1001b
+	.endm

arch/arm/mach-shmobile/setup-r8a7740.c

···
 
 void __init r8a7740_map_io(void)
 {
+	debug_ll_io_init();
 	iotable_init(r8a7740_io_desc, ARRAY_SIZE(r8a7740_io_desc));
 }
 

arch/arm/mach-shmobile/setup-r8a7779.c

···
 
 void __init r8a7779_map_io(void)
 {
+	debug_ll_io_init();
 	iotable_init(r8a7779_io_desc, ARRAY_SIZE(r8a7779_io_desc));
 }
 

arch/arm/mach-shmobile/setup-sh7372.c

···
 
 void __init sh7372_map_io(void)
 {
+	debug_ll_io_init();
 	iotable_init(sh7372_io_desc, ARRAY_SIZE(sh7372_io_desc));
 }
 

arch/arm/mach-shmobile/setup-sh73a0.c

···
 
 void __init sh73a0_map_io(void)
 {
+	debug_ll_io_init();
 	iotable_init(sh73a0_io_desc, ARRAY_SIZE(sh73a0_io_desc));
 }