reset: zynqmp: Add reset controller for ZynqMP SoC

Add firmware based reset controller for Xilinx ZynqMP SoC to let other
drivers to call reset functions. Driver is only tested on Xilinx ZynqMP but
support for Xilinx Versal can be simply added. That's why reset_id and
nr_reset are assigned in probe folder.
Driver is inpired by driver from Linux kernel.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

3 files changed, 110 insertions, 0 deletions

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index a42b3f0..d73daf5 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -197,4 +197,13 @@ config RESET_SCMI
 	  Enable this option if you want to support reset controller
 	  devices exposed by a SCMI agent based on SCMI reset domain
 	  protocol communication with a SCMI server.
+
+config RESET_ZYNQMP
+	bool "Reset Driver for Xilinx ZynqMP SoC's"
+	depends on DM_RESET && ZYNQMP_FIRMWARE
+	help
+	  Support for reset controller on Xilinx ZynqMP SoC. Driver is only
+	  passing request via Xilinx firmware interface to TF-A and PMU
+	  firmware.
+
 endmenu
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 8a0f528..d69486b 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -29,3 +29,4 @@ obj-$(CONFIG_RESET_SIFIVE) += reset-sifive.o
 obj-$(CONFIG_RESET_SYSCON) += reset-syscon.o
 obj-$(CONFIG_RESET_RASPBERRYPI) += reset-raspberrypi.o
 obj-$(CONFIG_RESET_SCMI) += reset-scmi.o
+obj-$(CONFIG_RESET_ZYNQMP) += reset-zynqmp.o
diff --git a/drivers/reset/reset-zynqmp.c b/drivers/reset/reset-zynqmp.c
new file mode 100644
index 0000000..5765234
--- /dev/null
+++ b/drivers/reset/reset-zynqmp.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Xilinx, Inc. - Michal Simek
+ */
+
+#define LOG_CATEGORY UCLASS_RESET
+
+#include <common.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <reset-uclass.h>
+#include <zynqmp_firmware.h>
+
+#define ZYNQMP_NR_RESETS	(ZYNQMP_PM_RESET_END - ZYNQMP_PM_RESET_START)
+#define ZYNQMP_RESET_ID		ZYNQMP_PM_RESET_START
+
+struct zynqmp_reset_priv {
+	u32 reset_id;
+	u32 nr_reset;
+};
+
+static int zynqmp_pm_reset_assert(const u32 reset,
+				  const enum zynqmp_pm_reset_action assert_flag)
+{
+	return xilinx_pm_request(PM_RESET_ASSERT, reset, assert_flag, 0, 0,
+				 NULL);
+}
+
+static int zynqmp_reset_assert(struct reset_ctl *rst)
+{
+	struct zynqmp_reset_priv *priv = dev_get_priv(rst->dev);
+
+	dev_dbg(rst->dev, "%s(rst=%p) (id=%lu)\n", __func__, rst, rst->id);
+
+	return zynqmp_pm_reset_assert(priv->reset_id + rst->id,
+				      PM_RESET_ACTION_ASSERT);
+}
+
+static int zynqmp_reset_deassert(struct reset_ctl *rst)
+{
+	struct zynqmp_reset_priv *priv = dev_get_priv(rst->dev);
+
+	dev_dbg(rst->dev, "%s(rst=%p) (id=%lu)\n", __func__, rst, rst->id);
+
+	return zynqmp_pm_reset_assert(priv->reset_id + rst->id,
+				      PM_RESET_ACTION_RELEASE);
+}
+
+static int zynqmp_reset_request(struct reset_ctl *rst)
+{
+	struct zynqmp_reset_priv *priv = dev_get_priv(rst->dev);
+
+	dev_dbg(rst->dev, "%s(rst=%p) (id=%lu) (nr_reset=%d)\n", __func__,
+		rst, rst->id, priv->nr_reset);
+
+	if (rst->id > priv->nr_reset)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int zynqmp_reset_free(struct reset_ctl *rst)
+{
+	struct zynqmp_reset_priv *priv = dev_get_priv(rst->dev);
+
+	dev_dbg(rst->dev, "%s(rst=%p) (id=%lu) (nr_reset=%d)\n", __func__,
+		rst, rst->id, priv->nr_reset);
+
+	return 0;
+}
+
+static int zynqmp_reset_probe(struct udevice *dev)
+{
+	struct zynqmp_reset_priv *priv = dev_get_priv(dev);
+
+	priv->reset_id = ZYNQMP_RESET_ID;
+	priv->nr_reset = ZYNQMP_NR_RESETS;
+	return 0;
+}
+
+const struct reset_ops zynqmp_reset_ops = {
+	.request = zynqmp_reset_request,
+	.rfree = zynqmp_reset_free,
+	.rst_assert = zynqmp_reset_assert,
+	.rst_deassert = zynqmp_reset_deassert,
+};
+
+static const struct udevice_id zynqmp_reset_ids[] = {
+	{ .compatible = "xlnx,zynqmp-reset" },
+	{ }
+};
+
+U_BOOT_DRIVER(zynqmp_reset) = {
+	.name		= "zynqmp_reset",
+	.id		= UCLASS_RESET,
+	.of_match	= zynqmp_reset_ids,
+	.ops		= &zynqmp_reset_ops,
+	.probe		= zynqmp_reset_probe,
+	.priv_auto	= sizeof(struct zynqmp_reset_priv),
+};