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.

We do not need this early reset driver for Stratix10, because on
arm64, Linux does not need the timers are that in reset. Linux is
able to run just fine with the internal armv8 timer. Thus, we use
a new binding "altr,stratix10-rst-mgr" for the Stratix10 platform.
The Stratix10 platform will continue to use the reset-simple platform
driver, while the 32-bit platforms(Cyclone5/Arria5/Arria10) will use
the early reset driver.
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
[p.zabel@pengutronix.de: fixed socfpga of_device_id in reset-simple]
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

arch/arm/mach-socfpga/socfpga.c

@@ -32,6 +32,8 @@ void __iomem *rst_manager_base_addr;
 void __iomem *sdr_ctl_base_addr;
 unsigned long socfpga_cpu1start_addr;
 
+extern void __init socfpga_reset_init(void);
+
 static void __init socfpga_sysmgr_init(void)
 {
 	struct device_node *np;
@@ -64,6 +66,7 @@ static void __init socfpga_init_irq(void)
 
 	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 @@ static void __init socfpga_arria10_init_irq(void)
 		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)

drivers/reset/Kconfig

@@ -109,7 +109,7 @@ config RESET_QCOM_PDC
 
 config RESET_SIMPLE
 	bool "Simple Reset Controller Driver" if COMPILE_TEST
-	default ARCH_SOCFPGA || ARCH_STM32 || ARCH_STRATIX10 || ARCH_SUNXI || ARCH_ZX || ARCH_ASPEED
+	default ARCH_STM32 || ARCH_STRATIX10 || ARCH_SUNXI || ARCH_ZX || ARCH_ASPEED
 	help
 	  This enables a simple reset controller driver for reset lines that
 	  that can be asserted and deasserted by toggling bits in a contiguous,
@@ -128,6 +128,14 @@ config RESET_STM32MP157
 	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 the SoCFPGA ARMv7 platforms. This
+	  driver gets initialized early during platform init calls.
+
 config RESET_SUNXI
 	bool "Allwinner SoCs Reset Driver" if COMPILE_TEST && !ARCH_SUNXI
 	default ARCH_SUNXI

drivers/reset/Makefile

@@ -19,6 +19,7 @@ obj-$(CONFIG_RESET_QCOM_AOSS) += reset-qcom-aoss.o
 obj-$(CONFIG_RESET_QCOM_PDC) += reset-qcom-pdc.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

drivers/reset/reset-simple.c

@@ -109,7 +109,7 @@ struct reset_simple_devdata {
 #define SOCFPGA_NR_BANKS	8
 
 static const struct reset_simple_devdata reset_simple_socfpga = {
-	.reg_offset = 0x10,
+	.reg_offset = 0x20,
 	.nr_resets = SOCFPGA_NR_BANKS * 32,
 	.status_active_low = true,
 };
@@ -120,7 +120,8 @@ static const struct reset_simple_devdata reset_simple_active_low = {
 };
 
 static const struct of_device_id reset_simple_dt_ids[] = {
-	{ .compatible = "altr,rst-mgr", .data = &reset_simple_socfpga },
+	{ .compatible = "altr,stratix10-rst-mgr",
+		.data = &reset_simple_socfpga },
 	{ .compatible = "st,stm32-rcc", },
 	{ .compatible = "allwinner,sun6i-a31-clock-reset",
 		.data = &reset_simple_active_low },
@@ -166,14 +167,6 @@ static int reset_simple_probe(struct platform_device *pdev)
 		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);

drivers/reset/reset-socfpga.c

+// 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"
+
+#define SOCFPGA_NR_BANKS	8
+void __init socfpga_reset_init(void);
+
+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 = 0x10;
+
+	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 0x10\n");
+	data->membase += reg_offset;
+
+	spin_lock_init(&data->lock);
+
+	data->rcdev.owner = THIS_MODULE;
+	data->rcdev.nr_resets = SOCFPGA_NR_BANKS * 32;
+	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);
+}