misc: add i.MX8 misc driver

Add i.MX8 MISC driver to handle the communication between
A35 Core and SCU.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Anatolij Gustschin <agust@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/drivers/misc/imx8/Makefile b/drivers/misc/imx8/Makefile
new file mode 100644
index 0000000..3395340
--- /dev/null
+++ b/drivers/misc/imx8/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0+
+
+obj-y += scu.o
diff --git a/drivers/misc/imx8/scu.c b/drivers/misc/imx8/scu.c
new file mode 100644
index 0000000..0647ddf
--- /dev/null
+++ b/drivers/misc/imx8/scu.c
@@ -0,0 +1,266 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2018 NXP
+ *
+ * Peng Fan <peng.fan@nxp.com>
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <dm.h>
+#include <dm/lists.h>
+#include <dm/root.h>
+#include <dm/device-internal.h>
+#include <asm/arch/sci/sci.h>
+#include <linux/iopoll.h>
+#include <misc.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct mu_type {
+	u32 tr[4];
+	u32 rr[4];
+	u32 sr;
+	u32 cr;
+};
+
+struct imx8_scu {
+	struct mu_type *base;
+	struct udevice *clk;
+	struct udevice *pinclk;
+};
+
+#define MU_CR_GIE_MASK		0xF0000000u
+#define MU_CR_RIE_MASK		0xF000000u
+#define MU_CR_GIR_MASK		0xF0000u
+#define MU_CR_TIE_MASK		0xF00000u
+#define MU_CR_F_MASK		0x7u
+#define MU_SR_TE0_MASK		BIT(23)
+#define MU_SR_RF0_MASK		BIT(27)
+#define MU_TR_COUNT		4
+#define MU_RR_COUNT		4
+
+static inline void mu_hal_init(struct mu_type *base)
+{
+	/* Clear GIEn, RIEn, TIEn, GIRn and ABFn. */
+	clrbits_le32(&base->cr, MU_CR_GIE_MASK | MU_CR_RIE_MASK |
+		     MU_CR_TIE_MASK | MU_CR_GIR_MASK | MU_CR_F_MASK);
+}
+
+static int mu_hal_sendmsg(struct mu_type *base, u32 reg_index, u32 msg)
+{
+	u32 mask = MU_SR_TE0_MASK >> reg_index;
+	u32 val;
+	int ret;
+
+	assert(reg_index < MU_TR_COUNT);
+
+	/* Wait TX register to be empty. */
+	ret = readl_poll_timeout(&base->sr, val, val & mask, 10000);
+	if (ret < 0) {
+		printf("%s timeout\n", __func__);
+		return -ETIMEDOUT;
+	}
+
+	writel(msg, &base->tr[reg_index]);
+
+	return 0;
+}
+
+static int mu_hal_receivemsg(struct mu_type *base, u32 reg_index, u32 *msg)
+{
+	u32 mask = MU_SR_RF0_MASK >> reg_index;
+	u32 val;
+	int ret;
+
+	assert(reg_index < MU_TR_COUNT);
+
+	/* Wait RX register to be full. */
+	ret = readl_poll_timeout(&base->sr, val, val & mask, 10000);
+	if (ret < 0) {
+		printf("%s timeout\n", __func__);
+		return -ETIMEDOUT;
+	}
+
+	*msg = readl(&base->rr[reg_index]);
+
+	return 0;
+}
+
+static int sc_ipc_read(struct mu_type *base, void *data)
+{
+	struct sc_rpc_msg_s *msg = (struct sc_rpc_msg_s *)data;
+	int ret;
+	u8 count = 0;
+
+	if (!msg)
+		return -EINVAL;
+
+	/* Read first word */
+	ret = mu_hal_receivemsg(base, 0, (u32 *)msg);
+	if (ret)
+		return ret;
+	count++;
+
+	/* Check size */
+	if (msg->size > SC_RPC_MAX_MSG) {
+		*((u32 *)msg) = 0;
+		return -EINVAL;
+	}
+
+	/* Read remaining words */
+	while (count < msg->size) {
+		ret = mu_hal_receivemsg(base, count % MU_RR_COUNT,
+					&msg->DATA.u32[count - 1]);
+		if (ret)
+			return ret;
+		count++;
+	}
+
+	return 0;
+}
+
+static int sc_ipc_write(struct mu_type *base, void *data)
+{
+	struct sc_rpc_msg_s *msg = (struct sc_rpc_msg_s *)data;
+	int ret;
+	u8 count = 0;
+
+	if (!msg)
+		return -EINVAL;
+
+	/* Check size */
+	if (msg->size > SC_RPC_MAX_MSG)
+		return -EINVAL;
+
+	/* Write first word */
+	ret = mu_hal_sendmsg(base, 0, *((u32 *)msg));
+	if (ret)
+		return ret;
+	count++;
+
+	/* Write remaining words */
+	while (count < msg->size) {
+		ret = mu_hal_sendmsg(base, count % MU_TR_COUNT,
+				     msg->DATA.u32[count - 1]);
+		if (ret)
+			return ret;
+		count++;
+	}
+
+	return 0;
+}
+
+/*
+ * Note the function prototype use msgid as the 2nd parameter, here
+ * we take it as no_resp.
+ */
+static int imx8_scu_call(struct udevice *dev, int no_resp, void *tx_msg,
+			 int tx_size, void *rx_msg, int rx_size)
+{
+	struct imx8_scu *priv = dev_get_priv(dev);
+	sc_err_t result;
+	int ret;
+
+	/* Expect tx_msg, rx_msg are the same value */
+	if (rx_msg && tx_msg != rx_msg)
+		printf("tx_msg %p, rx_msg %p\n", tx_msg, rx_msg);
+
+	ret = sc_ipc_write(priv->base, tx_msg);
+	if (ret)
+		return ret;
+	if (!no_resp) {
+		ret = sc_ipc_read(priv->base, rx_msg);
+		if (ret)
+			return ret;
+	}
+
+	result = RPC_R8((struct sc_rpc_msg_s *)tx_msg);
+
+	return sc_err_to_linux(result);
+}
+
+static int imx8_scu_probe(struct udevice *dev)
+{
+	struct imx8_scu *priv = dev_get_priv(dev);
+	fdt_addr_t addr;
+
+	debug("%s(dev=%p) (priv=%p)\n", __func__, dev, priv);
+
+	addr = devfdt_get_addr(dev);
+	if (addr == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	priv->base = (struct mu_type *)addr;
+
+	/* U-Boot not enable interrupts, so need to enable RX interrupts */
+	mu_hal_init(priv->base);
+
+	gd->arch.scu_dev = dev;
+
+	device_probe(priv->clk);
+	device_probe(priv->pinclk);
+
+	return 0;
+}
+
+static int imx8_scu_remove(struct udevice *dev)
+{
+	return 0;
+}
+
+static int imx8_scu_bind(struct udevice *dev)
+{
+	struct imx8_scu *priv = dev_get_priv(dev);
+	int ret;
+	struct udevice *child;
+	int node;
+
+	debug("%s(dev=%p)\n", __func__, dev);
+
+	node = fdt_node_offset_by_compatible(gd->fdt_blob, -1,
+					     "fsl,imx8qxp-clk");
+	if (node < 0)
+		panic("No clk node found\n");
+
+	ret = lists_bind_fdt(dev, offset_to_ofnode(node), &child);
+	if (ret)
+		return ret;
+
+	priv->clk = child;
+
+	node = fdt_node_offset_by_compatible(gd->fdt_blob, -1,
+					     "fsl,imx8qxp-iomuxc");
+	if (node < 0)
+		panic("No iomuxc node found\n");
+
+	ret = lists_bind_fdt(dev, offset_to_ofnode(node), &child);
+	if (ret)
+		return ret;
+
+	priv->pinclk = child;
+
+	return 0;
+}
+
+static struct misc_ops imx8_scu_ops = {
+	.call = imx8_scu_call,
+};
+
+static const struct udevice_id imx8_scu_ids[] = {
+	{ .compatible = "fsl,imx8qxp-mu" },
+	{ .compatible = "fsl,imx8-mu" },
+	{ }
+};
+
+U_BOOT_DRIVER(imx8_scu) = {
+	.name		= "imx8_scu",
+	.id		= UCLASS_MISC,
+	.of_match	= imx8_scu_ids,
+	.probe		= imx8_scu_probe,
+	.bind		= imx8_scu_bind,
+	.remove		= imx8_scu_remove,
+	.ops		= &imx8_scu_ops,
+	.priv_auto_alloc_size = sizeof(struct imx8_scu),
+	.flags		= DM_FLAG_PRE_RELOC,
+};