[PATCH v2 19/20] power: reset: add drivers for generic syscon reset and poweroff

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Many SoC reset/poweroff mechanisms can be represented using this generic
binding. Of the boards we support, at least the virt machines can
be rebooted and powered off by it. Import the Linux v5.11 state
of the driver to support this.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 arch/riscv/Kconfig                    |  1 +
 arch/riscv/dts/erizo.dtsi             |  2 +-
 drivers/clocksource/Kconfig           |  2 +-
 drivers/clocksource/timer-riscv.c     | 18 +++++-
 drivers/power/reset/Kconfig           | 14 ++++
 drivers/power/reset/Makefile          |  2 +
 drivers/power/reset/syscon-poweroff.c | 76 ++++++++++++++++++++++
 drivers/power/reset/syscon-reboot.c   | 92 +++++++++++++++++++++++++++
 8 files changed, 204 insertions(+), 3 deletions(-)
 create mode 100644 drivers/power/reset/syscon-poweroff.c
 create mode 100644 drivers/power/reset/syscon-reboot.c

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 50c4d145cf54..6e8bfdef14db 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -32,6 +32,7 @@ config MACH_ERIZO
 	select HAS_NMON
 	select USE_COMPRESSED_DTB
 	select RISCV_M_MODE
+	select RISCV_TIMER
 
 endchoice
 
diff --git a/arch/riscv/dts/erizo.dtsi b/arch/riscv/dts/erizo.dtsi
index 07534798ac75..e854a48ae55c 100644
--- a/arch/riscv/dts/erizo.dtsi
+++ b/arch/riscv/dts/erizo.dtsi
@@ -22,7 +22,7 @@
 
 		cpu@0 {
 			device_type = "cpu";
-			compatible = "cliffordwolf,picorv32";
+			compatible = "cliffordwolf,picorv32", "riscv";
 			clocks = <&ref_clk>;
 			reg = <0>;
 		};
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 2d8f5113ad8d..7bc69afd7820 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -101,7 +101,7 @@ config CLOCKSOURCE_TI_32K
 
 config RISCV_TIMER
 	bool "Timer for the RISC-V platform" if COMPILE_TEST
-	depends on RISCV && RISCV_SBI
+	depends on RISCV
 	help
 	  This enables the per-hart timer built into all RISC-V systems, which
 	  is accessed via both the SBI and the rdcycle instruction.  This is
diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
index 637285fd78a7..eb5ba2d8c226 100644
--- a/drivers/clocksource/timer-riscv.c
+++ b/drivers/clocksource/timer-riscv.c
@@ -13,7 +13,7 @@
 #include <asm/timer.h>
 #include <asm/csr.h>
 
-static u64 notrace riscv_timer_get_count(void)
+static u64 notrace riscv_timer_get_count_sbi(void)
 {
 	__maybe_unused u32 hi, lo;
 
@@ -28,6 +28,22 @@ static u64 notrace riscv_timer_get_count(void)
 	return ((u64)hi << 32) | lo;
 }
 
+static u64 notrace riscv_timer_get_count_rdcycle(void)
+{
+	u64 ticks;
+	asm volatile("rdcycle %0" : "=r" (ticks));
+
+	return ticks;
+}
+
+static u64 notrace riscv_timer_get_count(void)
+{
+	if (IS_ENABLED(CONFIG_RISCV_SBI))
+		return riscv_timer_get_count_sbi();
+	else
+		return riscv_timer_get_count_rdcycle();
+}
+
 static struct clocksource riscv_clocksource = {
 	.read		= riscv_timer_get_count,
 	.mask		= CLOCKSOURCE_MASK(64),
diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index f65e1f67fd59..e60037a6e637 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -14,3 +14,17 @@ config SYSCON_REBOOT_MODE
 	  get reboot mode arguments and store it in SYSCON mapped
 	  register, then the bootloader can read it to take different
 	  action according to the mode.
+
+config POWER_RESET_SYSCON
+	bool "Generic SYSCON regmap reset driver"
+	depends on OFDEVICE
+	select MFD_SYSCON
+	help
+	  Reboot support for generic SYSCON mapped register reset.
+
+config POWER_RESET_SYSCON_POWEROFF
+	bool "Generic SYSCON regmap poweroff driver"
+	depends on OFDEVICE
+	select MFD_SYSCON
+	help
+	  Poweroff support for generic SYSCON mapped register poweroff.
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index 56feec78cf26..a490dce87333 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -1,3 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_REBOOT_MODE) += reboot-mode.o
 obj-$(CONFIG_SYSCON_REBOOT_MODE) += syscon-reboot-mode.o
+obj-$(CONFIG_POWER_RESET_SYSCON) += syscon-reboot.o
+obj-$(CONFIG_POWER_RESET_SYSCON_POWEROFF) += syscon-poweroff.o
diff --git a/drivers/power/reset/syscon-poweroff.c b/drivers/power/reset/syscon-poweroff.c
new file mode 100644
index 000000000000..3664c4d8bd08
--- /dev/null
+++ b/drivers/power/reset/syscon-poweroff.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Generic Syscon Poweroff Driver
+ *
+ * Copyright (c) 2015, National Instruments Corp.
+ * Author: Moritz Fischer <moritz.fischer@ettus.com>
+ */
+
+#include <common.h>
+#include <init.h>
+#include <poweroff.h>
+#include <mfd/syscon.h>
+
+static struct regmap *map;
+static u32 offset;
+static u32 value;
+static u32 mask;
+
+static void syscon_poweroff(struct poweroff_handler *handler)
+{
+	/* Issue the poweroff */
+	regmap_update_bits(map, offset, mask, value);
+
+	mdelay(1000);
+
+	pr_emerg("Unable to poweroff system\n");
+}
+
+static int syscon_poweroff_probe(struct device_d *dev)
+{
+	int mask_err, value_err;
+
+	map = syscon_regmap_lookup_by_phandle(dev->device_node, "regmap");
+	if (IS_ERR(map)) {
+		dev_err(dev, "unable to get syscon");
+		return PTR_ERR(map);
+	}
+
+	if (of_property_read_u32(dev->device_node, "offset", &offset)) {
+		dev_err(dev, "unable to read 'offset'");
+		return -EINVAL;
+	}
+
+	value_err = of_property_read_u32(dev->device_node, "value", &value);
+	mask_err = of_property_read_u32(dev->device_node, "mask", &mask);
+	if (value_err && mask_err) {
+		dev_err(dev, "unable to read 'value' and 'mask'");
+		return -EINVAL;
+	}
+
+	if (value_err) {
+		/* support old binding */
+		value = mask;
+		mask = 0xFFFFFFFF;
+	} else if (mask_err) {
+		/* support value without mask*/
+		mask = 0xFFFFFFFF;
+	}
+
+	poweroff_handler_register_fn(syscon_poweroff);
+
+	return 0;
+}
+
+static const struct of_device_id syscon_poweroff_of_match[] = {
+	{ .compatible = "syscon-poweroff" },
+	{}
+};
+
+static struct driver_d syscon_poweroff_driver = {
+	.name = "syscon-poweroff",
+	.of_compatible = syscon_poweroff_of_match,
+	.probe = syscon_poweroff_probe,
+};
+
+coredevice_platform_driver(syscon_poweroff_driver);
diff --git a/drivers/power/reset/syscon-reboot.c b/drivers/power/reset/syscon-reboot.c
new file mode 100644
index 000000000000..2dbb6c1ddcb8
--- /dev/null
+++ b/drivers/power/reset/syscon-reboot.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Generic Syscon Reboot Driver
+ *
+ * Copyright (c) 2013, Applied Micro Circuits Corporation
+ * Author: Feng Kan <fkan@apm.com>
+ */
+#include <common.h>
+#include <init.h>
+#include <restart.h>
+#include <mfd/syscon.h>
+
+struct syscon_reboot_context {
+	struct regmap *map;
+	u32 offset;
+	u32 value;
+	u32 mask;
+	struct restart_handler restart_handler;
+};
+
+static void __noreturn syscon_restart_handle(struct restart_handler *this)
+{
+	struct syscon_reboot_context *ctx =
+			container_of(this, struct syscon_reboot_context,
+					restart_handler);
+
+	/* Issue the reboot */
+	regmap_update_bits(ctx->map, ctx->offset, ctx->mask, ctx->value);
+
+	mdelay(1000);
+
+	panic("Unable to restart system\n");
+}
+
+static int syscon_reboot_probe(struct device_d *dev)
+{
+	struct syscon_reboot_context *ctx;
+	int mask_err, value_err;
+	int err;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->map = syscon_regmap_lookup_by_phandle(dev->device_node, "regmap");
+	if (IS_ERR(ctx->map)) {
+		ctx->map = syscon_node_to_regmap(dev->parent->device_node);
+		if (IS_ERR(ctx->map))
+			return PTR_ERR(ctx->map);
+	}
+
+	if (of_property_read_u32(dev->device_node, "offset", &ctx->offset))
+		return -EINVAL;
+
+	value_err = of_property_read_u32(dev->device_node, "value", &ctx->value);
+	mask_err = of_property_read_u32(dev->device_node, "mask", &ctx->mask);
+	if (value_err && mask_err) {
+		dev_err(dev, "unable to read 'value' and 'mask'");
+		return -EINVAL;
+	}
+
+	if (value_err) {
+		/* support old binding */
+		ctx->value = ctx->mask;
+		ctx->mask = 0xFFFFFFFF;
+	} else if (mask_err) {
+		/* support value without mask*/
+		ctx->mask = 0xFFFFFFFF;
+	}
+
+	ctx->restart_handler.name = "syscon-reboot";
+	ctx->restart_handler.restart = syscon_restart_handle;
+	ctx->restart_handler.priority = 192;
+
+	err = restart_handler_register(&ctx->restart_handler);
+	if (err)
+		dev_err(dev, "can't register restart notifier\n");
+
+	return err;
+}
+
+static const struct of_device_id syscon_reboot_of_match[] = {
+	{ .compatible = "syscon-reboot" },
+	{}
+};
+
+static struct driver_d syscon_reboot_driver = {
+	.probe = syscon_reboot_probe,
+	.name = "syscon-reboot",
+	.of_compatible = syscon_reboot_of_match,
+};
+coredevice_platform_driver(syscon_reboot_driver);
-- 
2.29.2


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