reset: socfpga: add an early reset driver for SoCFPGA

Create a separate reset driver that uses the reset operations in reset-simple.
The reset driver for the SoCFPGA platform needs to register early in order to
be able bring online timers that needed early in the kernel bootup.

Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
diff --git a/arch/arm/mach-socfpga/socfpga.c b/arch/arm/mach-socfpga/socfpga.c
index dde14f7..cc64576 100644
--- a/arch/arm/mach-socfpga/socfpga.c
+++ b/arch/arm/mach-socfpga/socfpga.c
@@ -32,6 +32,8 @@
 void __iomem *sdr_ctl_base_addr;
 unsigned long socfpga_cpu1start_addr;
 
+extern void __init socfpga_reset_init(void);
+
 void __init socfpga_sysmgr_init(void)
 {
 	struct device_node *np;
@@ -64,6 +66,7 @@
 
 	if (IS_ENABLED(CONFIG_EDAC_ALTERA_OCRAM))
 		socfpga_init_ocram_ecc();
+	socfpga_reset_init();
 }
 
 static void __init socfpga_arria10_init_irq(void)
@@ -74,6 +77,7 @@
 		socfpga_init_arria10_l2_ecc();
 	if (IS_ENABLED(CONFIG_EDAC_ALTERA_OCRAM))
 		socfpga_init_arria10_ocram_ecc();
+	socfpga_reset_init();
 }
 
 static void socfpga_cyclone5_restart(enum reboot_mode mode, const char *cmd)
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 13d28fd..dcc5f1d 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -119,6 +119,13 @@
 	help
 	  This enables the RCC reset controller driver for STM32 MPUs.
 
+config RESET_SOCFPGA
+	bool "SoCFPGA Reset Driver" if COMPILE_TEST && !ARCH_SOCFPGA
+	default ARCH_SOCFPGA
+	select RESET_SIMPLE
+	help
+	  This enables the reset driver for SoCFPGA.
+
 config RESET_SUNXI
 	bool "Allwinner SoCs Reset Driver" if COMPILE_TEST && !ARCH_SUNXI
 	default ARCH_SUNXI
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 4243c38..d09bb41 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -18,6 +18,7 @@
 obj-$(CONFIG_RESET_QCOM_AOSS) += reset-qcom-aoss.o
 obj-$(CONFIG_RESET_SIMPLE) += reset-simple.o
 obj-$(CONFIG_RESET_STM32MP157) += reset-stm32mp1.o
+obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o
 obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o
 obj-$(CONFIG_RESET_TI_SCI) += reset-ti-sci.o
 obj-$(CONFIG_RESET_TI_SYSCON) += reset-ti-syscon.o
diff --git a/drivers/reset/reset-simple.c b/drivers/reset/reset-simple.c
index a91107f..483824f 100644
--- a/drivers/reset/reset-simple.c
+++ b/drivers/reset/reset-simple.c
@@ -106,21 +106,12 @@
 	bool status_active_low;
 };
 
-#define SOCFPGA_NR_BANKS	8
-
-static const struct reset_simple_devdata reset_simple_socfpga = {
-	.reg_offset = 0x10,
-	.nr_resets = SOCFPGA_NR_BANKS * 32,
-	.status_active_low = true,
-};
-
 static const struct reset_simple_devdata reset_simple_active_low = {
 	.active_low = true,
 	.status_active_low = true,
 };
 
 static const struct of_device_id reset_simple_dt_ids[] = {
-	{ .compatible = "altr,rst-mgr", .data = &reset_simple_socfpga },
 	{ .compatible = "st,stm32-rcc", },
 	{ .compatible = "allwinner,sun6i-a31-clock-reset",
 		.data = &reset_simple_active_low },
@@ -166,14 +157,6 @@
 		data->status_active_low = devdata->status_active_low;
 	}
 
-	if (of_device_is_compatible(dev->of_node, "altr,rst-mgr") &&
-	    of_property_read_u32(dev->of_node, "altr,modrst-offset",
-				 &reg_offset)) {
-		dev_warn(dev,
-			 "missing altr,modrst-offset property, assuming 0x%x!\n",
-			 reg_offset);
-	}
-
 	data->membase += reg_offset;
 
 	return devm_reset_controller_register(dev, &data->rcdev);
diff --git a/drivers/reset/reset-socfpga.c b/drivers/reset/reset-socfpga.c
new file mode 100644
index 0000000..b6e8fe8
--- /dev/null
+++ b/drivers/reset/reset-socfpga.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier:	GPL-2.0
+/*
+ * Copyright (C) 2018, Intel Corporation
+ * Copied from reset-sunxi.c
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+#include "reset-simple.h"
+
+static int a10_reset_init(struct device_node *np)
+{
+	struct reset_simple_data *data;
+	struct resource res;
+	resource_size_t size;
+	int ret;
+	u32 reg_offset = 0;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	ret = of_address_to_resource(np, 0, &res);
+	if (ret)
+		goto err_alloc;
+
+	size = resource_size(&res);
+	if (!request_mem_region(res.start, size, np->name)) {
+		ret = -EBUSY;
+		goto err_alloc;
+	}
+
+	data->membase = ioremap(res.start, size);
+	if (!data->membase) {
+		ret = -ENOMEM;
+		goto err_alloc;
+	}
+
+	if (of_property_read_u32(np, "altr,modrst-offset", &reg_offset))
+		pr_warn("missing altr,modrst-offset property, assuming 0x0\n");
+	data->membase += reg_offset;
+
+	spin_lock_init(&data->lock);
+
+	data->rcdev.owner = THIS_MODULE;
+	data->rcdev.nr_resets = 32 * 8;
+	data->rcdev.ops = &reset_simple_ops;
+	data->rcdev.of_node = np;
+	data->status_active_low = true;
+
+	return reset_controller_register(&data->rcdev);
+
+err_alloc:
+	kfree(data);
+	return ret;
+};
+
+/*
+ * These are the reset controller we need to initialize early on in
+ * our system, before we can even think of using a regular device
+ * driver for it.
+ * The controllers that we can register through the regular device
+ * model are handled by the simple reset driver directly.
+ */
+static const struct of_device_id socfpga_early_reset_dt_ids[] __initconst = {
+	{ .compatible = "altr,rst-mgr", },
+	{ /* sentinel */ },
+};
+
+void __init socfpga_reset_init(void)
+{
+	struct device_node *np;
+
+	for_each_matching_node(np, socfpga_early_reset_dt_ids)
+		a10_reset_init(np);
+}