MIPS: generic: Add support for Microsemi Ocelot

Introduce support for the MIPS based Microsemi Ocelot SoCs.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Allan Nielsen <Allan.Nielsen@microsemi.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/18858/
[jhogan@kernel.org: update ocelot_defconfig specification]
Signed-off-by: James Hogan <jhogan@kernel.org>

3 files changed, 95 insertions, 0 deletions

diff --git a/arch/mips/generic/Kconfig b/arch/mips/generic/Kconfig
index 2ff3b17bfab1..ba9b2c8cce68 100644
--- a/arch/mips/generic/Kconfig
+++ b/arch/mips/generic/Kconfig
@@ -27,6 +27,22 @@ config LEGACY_BOARD_SEAD3
 	  Enable this to include support for booting on MIPS SEAD-3 FPGA-based
 	  development boards, which boot using a legacy boot protocol.
 
+comment "MSCC Ocelot doesn't work with SEAD3 enabled"
+	depends on LEGACY_BOARD_SEAD3
+
+config LEGACY_BOARD_OCELOT
+	bool "Support MSCC Ocelot boards"
+	depends on LEGACY_BOARD_SEAD3=n
+	select LEGACY_BOARDS
+	select MSCC_OCELOT
+
+config MSCC_OCELOT
+	bool
+	select GPIOLIB
+	select MSCC_OCELOT_IRQ
+	select SYS_HAS_EARLY_PRINTK
+	select USE_GENERIC_EARLY_PRINTK_8250
+
 comment "FIT/UHI Boards"
 
 config FIT_IMAGE_FDT_BOSTON
diff --git a/arch/mips/generic/Makefile b/arch/mips/generic/Makefile
index 5c31e0c4697d..d03a36f869a4 100644
--- a/arch/mips/generic/Makefile
+++ b/arch/mips/generic/Makefile
@@ -14,5 +14,6 @@ obj-y += proc.o
 
 obj-$(CONFIG_YAMON_DT_SHIM)		+= yamon-dt.o
 obj-$(CONFIG_LEGACY_BOARD_SEAD3)	+= board-sead3.o
+obj-$(CONFIG_LEGACY_BOARD_OCELOT)	+= board-ocelot.o
 obj-$(CONFIG_KEXEC)			+= kexec.o
 obj-$(CONFIG_VIRT_BOARD_RANCHU)		+= board-ranchu.o
diff --git a/arch/mips/generic/board-ocelot.c b/arch/mips/generic/board-ocelot.c
new file mode 100644
index 000000000000..06d92fb37769
--- /dev/null
+++ b/arch/mips/generic/board-ocelot.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/*
+ * Microsemi MIPS SoC support
+ *
+ * Copyright (c) 2017 Microsemi Corporation
+ */
+#include <asm/machine.h>
+#include <asm/prom.h>
+
+#define DEVCPU_GCB_CHIP_REGS_CHIP_ID	0x71070000
+#define CHIP_ID_PART_ID			GENMASK(27, 12)
+
+#define OCELOT_PART_ID			(0x7514 << 12)
+
+#define UART_UART			0x70100000
+
+static __init bool ocelot_detect(void)
+{
+	u32 rev;
+	int idx;
+
+	/* Look for the TLB entry set up by redboot before trying to use it */
+	write_c0_entryhi(DEVCPU_GCB_CHIP_REGS_CHIP_ID);
+	mtc0_tlbw_hazard();
+	tlb_probe();
+	tlb_probe_hazard();
+	idx = read_c0_index();
+	if (idx < 0)
+		return 0;
+
+	/* A TLB entry exists, lets assume its usable and check the CHIP ID */
+	rev = __raw_readl((void __iomem *)DEVCPU_GCB_CHIP_REGS_CHIP_ID);
+
+	if ((rev & CHIP_ID_PART_ID) != OCELOT_PART_ID)
+		return 0;
+
+	/* Copy command line from bootloader early for Initrd detection */
+	if (fw_arg0 < 10 && (fw_arg1 & 0xFFF00000) == 0x80000000) {
+		unsigned int prom_argc = fw_arg0;
+		const char **prom_argv = (const char **)fw_arg1;
+
+		if (prom_argc > 1 && strlen(prom_argv[1]) > 0)
+			/* ignore all built-in args if any f/w args given */
+			strcpy(arcs_cmdline, prom_argv[1]);
+	}
+
+	return 1;
+}
+
+static void __init ocelot_earlyprintk_init(void)
+{
+	void __iomem *uart_base;
+
+	uart_base = ioremap_nocache(UART_UART, 0x20);
+	setup_8250_early_printk_port((unsigned long)uart_base, 2, 50000);
+}
+
+static void __init ocelot_late_init(void)
+{
+	ocelot_earlyprintk_init();
+}
+
+static __init const void *ocelot_fixup_fdt(const void *fdt,
+					   const void *match_data)
+{
+	/* This has to be done so late because ioremap needs to work */
+	late_time_init = ocelot_late_init;
+
+	return fdt;
+}
+
+extern char __dtb_ocelot_pcb123_begin[];
+
+MIPS_MACHINE(ocelot) = {
+	.fdt = __dtb_ocelot_pcb123_begin,
+	.fixup_fdt = ocelot_fixup_fdt,
+	.detect = ocelot_detect,
+};