[PATCHv2] reset: socfpga: add an early reset driver for SoCFPGA

[Dinh Nguyen]

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.

Signed-off-by: Dinh Nguyen <dinguyen@xxxxxxxxxx>
---
v2: Do not build separate reset driver for STRATIX10
    fix warning: symbol 'socfpga_reset_init' was not declared. Should
    it be static?
---
 arch/arm/mach-socfpga/socfpga.c |  4 ++
 drivers/reset/Kconfig           |  9 +++-
 drivers/reset/Makefile          |  1 +
 drivers/reset/reset-socfpga.c   | 88 +++++++++++++++++++++++++++++++++
 4 files changed, 101 insertions(+), 1 deletion(-)
 create mode 100644 drivers/reset/reset-socfpga.c

diff --git a/arch/arm/mach-socfpga/socfpga.c b/arch/arm/mach-socfpga/socfpga.c
index dde14f7bf2c3..cc64576c102b 100644
--- a/arch/arm/mach-socfpga/socfpga.c
+++ b/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);
+
 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)
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 13d28fdbdbb5..f10de5ce4753 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -100,7 +100,7 @@ config RESET_QCOM_AOSS
 
 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,
@@ -119,6 +119,13 @@ 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 && !ARCH_STRATIX10
+	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 4243c38228e2..d09bb41273f6 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_RESET_PISTACHIO) += reset-pistachio.o
 obj-$(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-socfpga.c b/drivers/reset/reset-socfpga.c
new file mode 100644
index 000000000000..b92769861d2b
--- /dev/null
+++ b/drivers/reset/reset-socfpga.c
@@ -0,0 +1,88 @@
+// 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);
+}
-- 
2.17.1