ARM: Prepare Realtek RTD1195

Introduce ARCH_REALTEK Kconfig option also for 32-bit Arm.

Override the text offset to cope with boot ROM occupying first 0xa800
bytes and further reservations up to 0xf4000 (compare Device Tree).

Add a custom machine_desc to enforce memory carveout for I/O registers.

Signed-off-by: Andreas Färber <[e-mail]>

MAINTAINERS

···
 L:	[e-mail] (moderated for non-subscribers)
 S:	Maintained
 F:	Documentation/devicetree/bindings/arm/realtek.yaml
+F:	arch/arm/mach-realtek/
 F:	arch/arm64/boot/dts/realtek/
 
 ARM/RENESAS ARM64 ARCHITECTURE

arch/arm/Kconfig

···
 
 source "arch/arm/mach-rda/Kconfig"
 
+source "arch/arm/mach-realtek/Kconfig"
+
 source "arch/arm/mach-realview/Kconfig"
 
 source "arch/arm/mach-rockchip/Kconfig"

arch/arm/Makefile

···
 textofs-y	:= 0x00008000
 # We don't want the htc bootloader to corrupt kernel during resume
 textofs-$(CONFIG_PM_H1940)      := 0x00108000
+# RTD1195 has Boot ROM at start of address space
+textofs-$(CONFIG_ARCH_REALTEK)  := 0x00108000
 # SA1111 DMA bug: we don't want the kernel to live in precious DMA-able memory
 ifeq ($(CONFIG_ARCH_SA1100),y)
 textofs-$(CONFIG_SA1111) := 0x00208000
···
 machine-$(CONFIG_ARCH_PXA)		+= pxa
 machine-$(CONFIG_ARCH_QCOM)		+= qcom
 machine-$(CONFIG_ARCH_RDA)		+= rda
+machine-$(CONFIG_ARCH_REALTEK)		+= realtek
 machine-$(CONFIG_ARCH_REALVIEW)		+= realview
 machine-$(CONFIG_ARCH_ROCKCHIP)		+= rockchip
 machine-$(CONFIG_ARCH_RPC)		+= rpc

arch/arm/mach-realtek/Kconfig

···
+# SPDX-License-Identifier: GPL-2.0-or-later
+menuconfig ARCH_REALTEK
+	bool "Realtek SoCs"
+	depends on ARCH_MULTI_V7
+	select ARM_GIC
+	select ARM_GLOBAL_TIMER
+	select CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
+	select GENERIC_IRQ_CHIP
+	select RESET_CONTROLLER
+	help
+	  This enables support for the Realtek RTD1195 SoC family.

arch/arm/mach-realtek/Makefile

···
+# SPDX-License-Identifier: GPL-2.0-or-later
+obj-y += rtd1195.o

arch/arm/mach-realtek/rtd1195.c

···
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Realtek RTD1195
+ *
+ * Copyright (c) 2017-2019 Andreas Färber
+ */
+
+#include <linux/memblock.h>
+#include <asm/mach/arch.h>
+
+static void __init rtd1195_memblock_remove(phys_addr_t base, phys_addr_t size)
+{
+	int ret;
+
+	ret = memblock_remove(base, size);
+	if (ret)
+		pr_err("Failed to remove memblock %pa (%d)\n", &base, ret);
+}
+
+static void __init rtd1195_reserve(void)
+{
+	/* Exclude boot ROM from RAM */
+	rtd1195_memblock_remove(0x00000000, 0x0000a800);
+
+	/* Exclude peripheral register spaces from RAM */
+	rtd1195_memblock_remove(0x18000000, 0x00070000);
+	rtd1195_memblock_remove(0x18100000, 0x01000000);
+}
+
+static const char *const rtd1195_dt_compat[] __initconst = {
+	"realtek,rtd1195",
+	NULL
+};
+
+DT_MACHINE_START(rtd1195, "Realtek RTD1195")
+	.dt_compat = rtd1195_dt_compat,
+	.reserve = rtd1195_reserve,
+	.l2c_aux_val = 0x0,
+	.l2c_aux_mask = ~0x0,
+MACHINE_END