This adds a driver for the blk-ctrl blocks found in the i.MX8M* line of
SoCs. The blk-ctrl is a top-level peripheral located in the various *MIX
power domains and interacts with the GPC power controller to provide the
peripherals in the power domain access to the NoC and ensures that those
peripherals are properly reset when their respective power domain is
brought back to life.

Software needs to do different things to make the bus handshake happen
after the the GPC *MIX domain is power up and before it is powered down.
As the requirements are quite different between the various blk-ctrls
there is a callback function provided to hook in the proper sequence.

The peripheral domains are quite uniform, they handle the soft clock
enables and resets in the blk-ctrl address space and sequencing with the
upstream GPC power domains.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
---
This commit includes the full code to drive the VPUMIX domain on the
i.MX8MM, as the skeleton driver would probably be harder to review
without the context provided by one blk-ctrl implementation. Other
blk-ctrl implementations will follow, based on this overall structure.
---
 drivers/soc/imx/Makefile         |   1 +
 drivers/soc/imx/imx8m-blk-ctrl.c | 455 +++++++++++++++++++++++++++++++
 2 files changed, 456 insertions(+)
 create mode 100644 drivers/soc/imx/imx8m-blk-ctrl.c

diff --git a/drivers/soc/imx/Makefile b/drivers/soc/imx/Makefile
index 078dc918f4f3..8a707077914c 100644
--- a/drivers/soc/imx/Makefile
+++ b/drivers/soc/imx/Makefile

@@ -5,3 +5,4 @@ endif
 obj-$(CONFIG_HAVE_IMX_GPC) += gpc.o
 obj-$(CONFIG_IMX_GPCV2_PM_DOMAINS) += gpcv2.o
 obj-$(CONFIG_SOC_IMX8M) += soc-imx8m.o
+obj-$(CONFIG_SOC_IMX8M) += imx8m-blk-ctrl.o

diff --git a/drivers/soc/imx/imx8m-blk-ctrl.c b/drivers/soc/imx/imx8m-blk-ctrl.c
new file mode 100644
index 000000000000..3dd17b903636
--- /dev/null
+++ b/drivers/soc/imx/imx8m-blk-ctrl.c

@@ -0,0 +1,455 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * Copyright 2021 Pengutronix, Lucas Stach <kernel@pengutronix.de>
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/clk.h>
+
+#include <dt-bindings/power/imx8mm-power.h>
+
+#define BLK_SFT_RSTN	0x0
+#define BLK_CLK_EN	0x4
+
+struct imx8m_blk_ctrl_domain;
+
+struct imx8m_blk_ctrl {
+	struct device *dev;
+	struct notifier_block power_nb;
+	struct device *bus_power_dev;
+	struct regmap *regmap;
+	struct imx8m_blk_ctrl_domain *domains;
+	struct genpd_onecell_data onecell_data;
+};
+
+struct imx8m_blk_ctrl_domain_data {
+	const char *name;
+	const char **clk_names;