[PATCH v4 05/10] riscv: Add support for MIPS GIC syscon on RISC-V SoCs

[Uros Stajic]

From: Chao-ying Fu <cfu at mips.com>

Add basic support for the MIPS GIC syscon used on the P8700 SoC.
Enables access to interrupt control via device tree matching.

Signed-off-by: Chao-ying Fu <cfu at mips.com>
Signed-off-by: Uros Stajic <uros.stajic at htecgroup.com>
---
 arch/riscv/Kconfig                  | 11 +++++++
 arch/riscv/lib/Makefile             |  1 +
 arch/riscv/lib/mips_gic.c           | 47 +++++++++++++++++++++++++++++
 board/mips/boston-riscv/MAINTAINERS |  1 +
 4 files changed, 60 insertions(+)
 create mode 100644 arch/riscv/lib/mips_gic.c

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 9e176522e73..6e1c0686db5 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -389,6 +389,17 @@ config SIFIVE_CACHE
 	help
 	  This enables the operations to configure SiFive cache
 
+config MIPS_GIC
+	bool
+	depends on RISCV_MMODE || SPL_RISCV_MMODE
+	select REGMAP
+	select SYSCON
+	select SPL_REGMAP if SPL
+	select SPL_SYSCON if SPL
+	help
+	  The MIPS GIC block holds memory-mapped control and status registers
+	  associated with software and timer interrupts.
+
 config ANDES_PLICSW
 	bool
 	depends on RISCV_MMODE || SPL_RISCV_MMODE
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index db8d235c699..692b56cc3f0 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_SYS_CACHE_THEAD_CMO) += thead_cmo.o
 ifeq ($(CONFIG_$(PHASE_)RISCV_MMODE),y)
 obj-$(CONFIG_$(PHASE_)RISCV_ACLINT) += aclint_ipi.o
 obj-$(CONFIG_ANDES_PLICSW) += andes_plicsw.o
+obj-$(CONFIG_MIPS_GIC) += mips_gic.o
 else
 obj-$(CONFIG_SBI) += sbi.o
 obj-$(CONFIG_SBI_IPI) += sbi_ipi.o
diff --git a/arch/riscv/lib/mips_gic.c b/arch/riscv/lib/mips_gic.c
new file mode 100644
index 00000000000..7d761c58e74
--- /dev/null
+++ b/arch/riscv/lib/mips_gic.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021, Chao-ying Fu <cfu at mips.com>
+ *
+ * U-Boot syscon driver for MIPS GIC.
+ */
+
+#include <dm.h>
+#include <regmap.h>
+#include <syscon.h>
+#include <asm/io.h>
+#include <asm/syscon.h>
+#include <linux/err.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int riscv_init_ipi(void)
+{
+	return 0;
+}
+
+int riscv_send_ipi(int hart)
+{
+	return 0;
+}
+
+int riscv_clear_ipi(int hart)
+{
+	return 0;
+}
+
+int riscv_get_ipi(int hart, int *pending)
+{
+	return 0;
+}
+
+static const struct udevice_id mips_gic_ids[] = {
+	{ .compatible = "mips,gic0", .data = RISCV_SYSCON_PLICSW },
+	{ }
+};
+
+U_BOOT_DRIVER(mips_gic) = {
+	.name		= "mips_gic",
+	.id		= UCLASS_SYSCON,
+	.of_match	= mips_gic_ids,
+	.flags		= DM_FLAG_PRE_RELOC,
+};
diff --git a/board/mips/boston-riscv/MAINTAINERS b/board/mips/boston-riscv/MAINTAINERS
index bc59a628c79..0d9a951441f 100644
--- a/board/mips/boston-riscv/MAINTAINERS
+++ b/board/mips/boston-riscv/MAINTAINERS
@@ -8,3 +8,4 @@ F:  arch/riscv/include/asm/arch-p8700/
 F:  configs/boston-p8700_defconfig
 F:  arch/riscv/dts/boston-p8700.dts
 F:  drivers/gpio/eg20t-gpio.c
+F:  arch/riscv/lib/mips_gic.c
-- 
2.34.1