reset: aspeed: Add AST2600 reset support

Add controller reset support through the
System Control Unit (SCU) of AST2600 SoC.

Signed-off-by: Chia-Wei, Wang <chiawei_wang@aspeedtech.com>
Reviewed-by: Ryan Chen <ryan_chen@aspeedtech.com>

3 files changed, 118 insertions, 0 deletions

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 33c2736554..f5b3f8826f 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -81,6 +81,15 @@ config RESET_AST2500
 	  Say Y if you want to control reset signals of different peripherals
 	  through System Control Unit (SCU).
 
+config RESET_AST2600
+	bool "Reset controller driver for AST2600 SoCs"
+	depends on DM_RESET
+	default y if ASPEED_AST2600
+	help
+	  Support for reset controller on AST2600 SoC.
+	  Say Y if you want to control reset signals of different peripherals
+	  through System Control Unit (SCU).
+
 config RESET_ROCKCHIP
 	bool "Reset controller driver for Rockchip SoCs"
 	depends on DM_RESET && ARCH_ROCKCHIP && CLK
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index fa52aa3329..8a0f528076 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_RESET_HSDK) += reset-hsdk.o
 obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o
 obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o
 obj-$(CONFIG_RESET_AST2500) += reset-ast2500.o
+obj-$(CONFIG_RESET_AST2600) += reset-ast2600.o
 obj-$(CONFIG_RESET_ROCKCHIP) += reset-rockchip.o
 obj-$(CONFIG_RESET_MESON) += reset-meson.o
 obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o
diff --git a/drivers/reset/reset-ast2600.c b/drivers/reset/reset-ast2600.c
new file mode 100644
index 0000000000..f64adaf74e
--- /dev/null
+++ b/drivers/reset/reset-ast2600.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2020 ASPEED Technology Inc.
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <log.h>
+#include <misc.h>
+#include <reset.h>
+#include <reset-uclass.h>
+#include <linux/err.h>
+#include <asm/io.h>
+#include <asm/arch/scu_ast2600.h>
+
+struct ast2600_reset_priv {
+	struct ast2600_scu *scu;
+};
+
+static int ast2600_reset_request(struct reset_ctl *reset_ctl)
+{
+	debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,
+	      reset_ctl->dev, reset_ctl->id);
+
+	return 0;
+}
+
+static int ast2600_reset_free(struct reset_ctl *reset_ctl)
+{
+	debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,
+	      reset_ctl->dev, reset_ctl->id);
+
+	return 0;
+}
+
+static int ast2600_reset_assert(struct reset_ctl *reset_ctl)
+{
+	struct ast2600_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+	struct ast2600_scu *scu = priv->scu;
+
+	debug("%s: reset_ctl->id: %lu\n", __func__, reset_ctl->id);
+
+	if (reset_ctl->id < 32)
+		writel(BIT(reset_ctl->id), scu->modrst_ctrl1);
+	else
+		writel(BIT(reset_ctl->id - 32), scu->modrst_ctrl2);
+
+	return 0;
+}
+
+static int ast2600_reset_deassert(struct reset_ctl *reset_ctl)
+{
+	struct ast2600_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+	struct ast2600_scu *scu = priv->scu;
+
+	debug("%s: reset_ctl->id: %lu\n", __func__, reset_ctl->id);
+
+	if (reset_ctl->id < 32)
+		writel(BIT(reset_ctl->id), scu->modrst_clr1);
+	else
+		writel(BIT(reset_ctl->id - 32), scu->modrst_clr2);
+
+	return 0;
+}
+
+static int ast2600_reset_probe(struct udevice *dev)
+{
+	int rc;
+	struct ast2600_reset_priv *priv = dev_get_priv(dev);
+	struct udevice *scu_dev;
+
+	/* get SCU base from clock device */
+	rc = uclass_get_device_by_driver(UCLASS_CLK,
+					 DM_DRIVER_GET(aspeed_ast2600_scu), &scu_dev);
+	if (rc) {
+		debug("%s: clock device not found, rc=%d\n", __func__, rc);
+		return rc;
+	}
+
+	priv->scu = devfdt_get_addr_ptr(scu_dev);
+	if (IS_ERR_OR_NULL(priv->scu)) {
+		debug("%s: invalid SCU base pointer\n", __func__);
+		return PTR_ERR(priv->scu);
+	}
+
+	return 0;
+}
+
+static const struct udevice_id ast2600_reset_ids[] = {
+	{ .compatible = "aspeed,ast2600-reset" },
+	{ }
+};
+
+struct reset_ops ast2600_reset_ops = {
+	.request = ast2600_reset_request,
+	.rfree = ast2600_reset_free,
+	.rst_assert = ast2600_reset_assert,
+	.rst_deassert = ast2600_reset_deassert,
+};
+
+U_BOOT_DRIVER(ast2600_reset) = {
+	.name = "ast2600_reset",
+	.id = UCLASS_RESET,
+	.of_match = ast2600_reset_ids,
+	.probe = ast2600_reset_probe,
+	.ops = &ast2600_reset_ops,
+	.priv_auto = sizeof(struct ast2600_reset_priv),
+};