firmware: arm_scmi: Add initial support for i.MX BBM protocol

i.MX95 has a battery-backed module(BBM), which has persistent storage
(GPR), an RTC, and the ON/OFF button. The System Manager(SM) firmware
use SCMI vendor protocol(SCMI BBM) to let agent be able to use GPR, RTC
and ON/OFF button.

Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Message-Id: <20240823-imx95-bbm-misc-v2-v8-2-e600ed9e9271@nxp.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/Kconfig

@@ -70,6 +70,7 @@ config ARM_SCMI_DEBUG_COUNTERS
 	  SCMI monitoring.
 
 source "drivers/firmware/arm_scmi/transports/Kconfig"
+source "drivers/firmware/arm_scmi/vendors/imx/Kconfig"
 
 endif #ARM_SCMI_PROTOCOL
 

drivers/firmware/arm_scmi/Makefile

@@ -11,6 +11,7 @@ scmi-protocols-y += pinctrl.o
 scmi-module-objs := $(scmi-driver-y) $(scmi-protocols-y) $(scmi-transport-y)
 
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += transports/
+obj-$(CONFIG_ARM_SCMI_PROTOCOL) += vendors/imx/
 
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += scmi-core.o
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += scmi-module.o

drivers/firmware/arm_scmi/vendors/imx/Kconfig

@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "ARM SCMI NXP i.MX Vendor Protocols"
+
+config IMX_SCMI_BBM_EXT
+	tristate "i.MX SCMI BBM EXTENSION"
+	depends on ARM_SCMI_PROTOCOL || (COMPILE_TEST && OF)
+	default y if ARCH_MXC
+	help
+	  This enables i.MX System BBM control logic which supports RTC
+	  and BUTTON.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called imx-sm-bbm.
+
+endmenu

drivers/firmware/arm_scmi/vendors/imx/Makefile

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_IMX_SCMI_BBM_EXT) += imx-sm-bbm.o

drivers/firmware/arm_scmi/vendors/imx/imx-sm-bbm.c

@@ -0,0 +1,383 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * System Control and Management Interface (SCMI) NXP BBM Protocol
+ *
+ * Copyright 2024 NXP
+ */
+
+#define pr_fmt(fmt) "SCMI Notifications BBM - " fmt
+
+#include <linux/bits.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/scmi_protocol.h>
+#include <linux/scmi_imx_protocol.h>
+
+#include "../../protocols.h"
+#include "../../notify.h"
+
+#define SCMI_PROTOCOL_SUPPORTED_VERSION		0x10000
+
+enum scmi_imx_bbm_protocol_cmd {
+	IMX_BBM_GPR_SET = 0x3,
+	IMX_BBM_GPR_GET = 0x4,
+	IMX_BBM_RTC_ATTRIBUTES = 0x5,
+	IMX_BBM_RTC_TIME_SET = 0x6,
+	IMX_BBM_RTC_TIME_GET = 0x7,
+	IMX_BBM_RTC_ALARM_SET = 0x8,
+	IMX_BBM_BUTTON_GET = 0x9,
+	IMX_BBM_RTC_NOTIFY = 0xA,
+	IMX_BBM_BUTTON_NOTIFY = 0xB,
+};
+
+#define GET_RTCS_NR(x)	le32_get_bits((x), GENMASK(23, 16))
+#define GET_GPRS_NR(x)	le32_get_bits((x), GENMASK(15, 0))
+
+#define SCMI_IMX_BBM_NOTIFY_RTC_UPDATED		BIT(2)
+#define SCMI_IMX_BBM_NOTIFY_RTC_ROLLOVER	BIT(1)
+#define SCMI_IMX_BBM_NOTIFY_RTC_ALARM		BIT(0)
+
+#define SCMI_IMX_BBM_RTC_ALARM_ENABLE_FLAG	BIT(0)
+
+#define SCMI_IMX_BBM_NOTIFY_RTC_FLAG	\
+	(SCMI_IMX_BBM_NOTIFY_RTC_UPDATED | SCMI_IMX_BBM_NOTIFY_RTC_ROLLOVER | \
+	 SCMI_IMX_BBM_NOTIFY_RTC_ALARM)
+
+#define SCMI_IMX_BBM_EVENT_RTC_MASK		GENMASK(31, 24)
+
+struct scmi_imx_bbm_info {
+	u32 version;
+	int nr_rtc;
+	int nr_gpr;
+};
+
+struct scmi_msg_imx_bbm_protocol_attributes {
+	__le32 attributes;
+};
+
+struct scmi_imx_bbm_set_time {
+	__le32 id;
+	__le32 flags;
+	__le32 value_low;
+	__le32 value_high;
+};
+
+struct scmi_imx_bbm_get_time {
+	__le32 id;
+	__le32 flags;
+};
+
+struct scmi_imx_bbm_alarm_time {
+	__le32 id;
+	__le32 flags;
+	__le32 value_low;
+	__le32 value_high;
+};
+
+struct scmi_msg_imx_bbm_rtc_notify {
+	__le32 rtc_id;
+	__le32 flags;
+};
+
+struct scmi_msg_imx_bbm_button_notify {
+	__le32 flags;
+};
+
+struct scmi_imx_bbm_notify_payld {
+	__le32 flags;
+};
+
+static int scmi_imx_bbm_attributes_get(const struct scmi_protocol_handle *ph,
+				       struct scmi_imx_bbm_info *pi)
+{
+	int ret;
+	struct scmi_xfer *t;
+	struct scmi_msg_imx_bbm_protocol_attributes *attr;
+
+	ret = ph->xops->xfer_get_init(ph, PROTOCOL_ATTRIBUTES, 0, sizeof(*attr), &t);
+	if (ret)
+		return ret;
+
+	attr = t->rx.buf;
+
+	ret = ph->xops->do_xfer(ph, t);
+	if (!ret) {
+		pi->nr_rtc = GET_RTCS_NR(attr->attributes);
+		pi->nr_gpr = GET_GPRS_NR(attr->attributes);
+	}
+
+	ph->xops->xfer_put(ph, t);
+
+	return ret;
+}
+
+static int scmi_imx_bbm_notify(const struct scmi_protocol_handle *ph,
+			       u32 src_id, int message_id, bool enable)
+{
+	int ret;
+	struct scmi_xfer *t;
+
+	if (message_id == IMX_BBM_RTC_NOTIFY) {
+		struct scmi_msg_imx_bbm_rtc_notify *rtc_notify;
+
+		ret = ph->xops->xfer_get_init(ph, message_id,
+					      sizeof(*rtc_notify), 0, &t);
+		if (ret)
+			return ret;
+
+		rtc_notify = t->tx.buf;
+		rtc_notify->rtc_id = cpu_to_le32(0);
+		rtc_notify->flags =
+			cpu_to_le32(enable ? SCMI_IMX_BBM_NOTIFY_RTC_FLAG : 0);
+	} else if (message_id == IMX_BBM_BUTTON_NOTIFY) {
+		struct scmi_msg_imx_bbm_button_notify *button_notify;
+
+		ret = ph->xops->xfer_get_init(ph, message_id,
+					      sizeof(*button_notify), 0, &t);
+		if (ret)
+			return ret;
+
+		button_notify = t->tx.buf;
+		button_notify->flags = cpu_to_le32(enable ? 1 : 0);
+	} else {
+		return -EINVAL;
+	}
+
+	ret = ph->xops->do_xfer(ph, t);
+
+	ph->xops->xfer_put(ph, t);
+	return ret;
+}
+
+static enum scmi_imx_bbm_protocol_cmd evt_2_cmd[] = {
+	IMX_BBM_RTC_NOTIFY,
+	IMX_BBM_BUTTON_NOTIFY
+};
+
+static int scmi_imx_bbm_set_notify_enabled(const struct scmi_protocol_handle *ph,
+					   u8 evt_id, u32 src_id, bool enable)
+{
+	int ret, cmd_id;
+
+	if (evt_id >= ARRAY_SIZE(evt_2_cmd))
+		return -EINVAL;
+
+	cmd_id = evt_2_cmd[evt_id];
+	ret = scmi_imx_bbm_notify(ph, src_id, cmd_id, enable);
+	if (ret)
+		pr_debug("FAIL_ENABLED - evt[%X] dom[%d] - ret:%d\n",
+			 evt_id, src_id, ret);
+
+	return ret;
+}
+
+static void *scmi_imx_bbm_fill_custom_report(const struct scmi_protocol_handle *ph,
+					     u8 evt_id, ktime_t timestamp,
+					     const void *payld, size_t payld_sz,
+					     void *report, u32 *src_id)
+{
+	const struct scmi_imx_bbm_notify_payld *p = payld;
+	struct scmi_imx_bbm_notif_report *r = report;
+
+	if (sizeof(*p) != payld_sz)
+		return NULL;
+
+	if (evt_id == SCMI_EVENT_IMX_BBM_RTC) {
+		r->is_rtc = true;
+		r->is_button = false;
+		r->timestamp = timestamp;
+		r->rtc_id = le32_get_bits(p->flags, SCMI_IMX_BBM_EVENT_RTC_MASK);
+		r->rtc_evt = le32_get_bits(p->flags, SCMI_IMX_BBM_NOTIFY_RTC_FLAG);
+		dev_dbg(ph->dev, "RTC: %d evt: %x\n", r->rtc_id, r->rtc_evt);
+		*src_id = r->rtc_evt;
+	} else if (evt_id == SCMI_EVENT_IMX_BBM_BUTTON) {
+		r->is_rtc = false;
+		r->is_button = true;
+		r->timestamp = timestamp;
+		dev_dbg(ph->dev, "BBM Button\n");
+		*src_id = 0;
+	} else {
+		WARN_ON_ONCE(1);
+		return NULL;
+	}
+
+	return r;
+}
+
+static const struct scmi_event scmi_imx_bbm_events[] = {
+	{
+		.id = SCMI_EVENT_IMX_BBM_RTC,
+		.max_payld_sz = sizeof(struct scmi_imx_bbm_notify_payld),
+		.max_report_sz = sizeof(struct scmi_imx_bbm_notif_report),
+	},
+	{
+		.id = SCMI_EVENT_IMX_BBM_BUTTON,
+		.max_payld_sz = sizeof(struct scmi_imx_bbm_notify_payld),
+		.max_report_sz = sizeof(struct scmi_imx_bbm_notif_report),
+	},
+};
+
+static const struct scmi_event_ops scmi_imx_bbm_event_ops = {
+	.set_notify_enabled = scmi_imx_bbm_set_notify_enabled,
+	.fill_custom_report = scmi_imx_bbm_fill_custom_report,
+};
+
+static const struct scmi_protocol_events scmi_imx_bbm_protocol_events = {
+	.queue_sz = SCMI_PROTO_QUEUE_SZ,
+	.ops = &scmi_imx_bbm_event_ops,
+	.evts = scmi_imx_bbm_events,
+	.num_events = ARRAY_SIZE(scmi_imx_bbm_events),
+	.num_sources = 1,
+};
+
+static int scmi_imx_bbm_rtc_time_set(const struct scmi_protocol_handle *ph,
+				     u32 rtc_id, u64 sec)
+{
+	struct scmi_imx_bbm_info *pi = ph->get_priv(ph);
+	struct scmi_imx_bbm_set_time *cfg;
+	struct scmi_xfer *t;
+	int ret;
+
+	if (rtc_id >= pi->nr_rtc)
+		return -EINVAL;
+
+	ret = ph->xops->xfer_get_init(ph, IMX_BBM_RTC_TIME_SET, sizeof(*cfg), 0, &t);
+	if (ret)
+		return ret;
+
+	cfg = t->tx.buf;
+	cfg->id = cpu_to_le32(rtc_id);
+	cfg->flags = 0;
+	cfg->value_low = cpu_to_le32(lower_32_bits(sec));
+	cfg->value_high = cpu_to_le32(upper_32_bits(sec));
+
+	ret = ph->xops->do_xfer(ph, t);
+
+	ph->xops->xfer_put(ph, t);
+
+	return ret;
+}
+
+static int scmi_imx_bbm_rtc_time_get(const struct scmi_protocol_handle *ph,
+				     u32 rtc_id, u64 *value)
+{
+	struct scmi_imx_bbm_info *pi = ph->get_priv(ph);
+	struct scmi_imx_bbm_get_time *cfg;
+	struct scmi_xfer *t;
+	int ret;
+
+	if (rtc_id >= pi->nr_rtc)
+		return -EINVAL;
+
+	ret = ph->xops->xfer_get_init(ph, IMX_BBM_RTC_TIME_GET, sizeof(*cfg),
+				      sizeof(u64), &t);
+	if (ret)
+		return ret;
+
+	cfg = t->tx.buf;
+	cfg->id = cpu_to_le32(rtc_id);
+	cfg->flags = 0;
+
+	ret = ph->xops->do_xfer(ph, t);
+	if (!ret)
+		*value = get_unaligned_le64(t->rx.buf);
+
+	ph->xops->xfer_put(ph, t);
+
+	return ret;
+}
+
+static int scmi_imx_bbm_rtc_alarm_set(const struct scmi_protocol_handle *ph,
+				      u32 rtc_id, bool enable, u64 sec)
+{
+	struct scmi_imx_bbm_info *pi = ph->get_priv(ph);
+	struct scmi_imx_bbm_alarm_time *cfg;
+	struct scmi_xfer *t;
+	int ret;
+
+	if (rtc_id >= pi->nr_rtc)
+		return -EINVAL;
+
+	ret = ph->xops->xfer_get_init(ph, IMX_BBM_RTC_ALARM_SET, sizeof(*cfg), 0, &t);
+	if (ret)
+		return ret;
+
+	cfg = t->tx.buf;
+	cfg->id = cpu_to_le32(rtc_id);
+	cfg->flags = enable ?
+		     cpu_to_le32(SCMI_IMX_BBM_RTC_ALARM_ENABLE_FLAG) : 0;
+	cfg->value_low = cpu_to_le32(lower_32_bits(sec));
+	cfg->value_high = cpu_to_le32(upper_32_bits(sec));
+
+	ret = ph->xops->do_xfer(ph, t);
+
+	ph->xops->xfer_put(ph, t);
+
+	return ret;
+}
+
+static int scmi_imx_bbm_button_get(const struct scmi_protocol_handle *ph, u32 *state)
+{
+	struct scmi_xfer *t;
+	int ret;
+
+	ret = ph->xops->xfer_get_init(ph, IMX_BBM_BUTTON_GET, 0, sizeof(u32), &t);
+	if (ret)
+		return ret;
+
+	ret = ph->xops->do_xfer(ph, t);
+	if (!ret)
+		*state = get_unaligned_le32(t->rx.buf);
+
+	ph->xops->xfer_put(ph, t);
+
+	return ret;
+}
+
+static const struct scmi_imx_bbm_proto_ops scmi_imx_bbm_proto_ops = {
+	.rtc_time_get = scmi_imx_bbm_rtc_time_get,
+	.rtc_time_set = scmi_imx_bbm_rtc_time_set,
+	.rtc_alarm_set = scmi_imx_bbm_rtc_alarm_set,
+	.button_get = scmi_imx_bbm_button_get,
+};
+
+static int scmi_imx_bbm_protocol_init(const struct scmi_protocol_handle *ph)
+{
+	u32 version;
+	int ret;
+	struct scmi_imx_bbm_info *binfo;
+
+	ret = ph->xops->version_get(ph, &version);
+	if (ret)
+		return ret;
+
+	dev_info(ph->dev, "NXP SM BBM Version %d.%d\n",
+		 PROTOCOL_REV_MAJOR(version), PROTOCOL_REV_MINOR(version));
+
+	binfo = devm_kzalloc(ph->dev, sizeof(*binfo), GFP_KERNEL);
+	if (!binfo)
+		return -ENOMEM;
+
+	ret = scmi_imx_bbm_attributes_get(ph, binfo);
+	if (ret)
+		return ret;
+
+	return ph->set_priv(ph, binfo, version);
+}
+
+static const struct scmi_protocol scmi_imx_bbm = {
+	.id = SCMI_PROTOCOL_IMX_BBM,
+	.owner = THIS_MODULE,
+	.instance_init = &scmi_imx_bbm_protocol_init,
+	.ops = &scmi_imx_bbm_proto_ops,
+	.events = &scmi_imx_bbm_protocol_events,
+	.supported_version = SCMI_PROTOCOL_SUPPORTED_VERSION,
+	.vendor_id = "NXP",
+	.sub_vendor_id = "IMX",
+};
+module_scmi_protocol(scmi_imx_bbm);
+
+MODULE_DESCRIPTION("i.MX SCMI BBM driver");
+MODULE_LICENSE("GPL");

include/linux/scmi_imx_protocol.h

@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * SCMI Message Protocol driver NXP extension header
+ *
+ * Copyright 2024 NXP.
+ */
+
+#ifndef _LINUX_SCMI_NXP_PROTOCOL_H
+#define _LINUX_SCMI_NXP_PROTOCOL_H
+
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/notifier.h>
+#include <linux/types.h>
+
+enum scmi_nxp_protocol {
+	SCMI_PROTOCOL_IMX_BBM = 0x81,
+};
+
+struct scmi_imx_bbm_proto_ops {
+	int (*rtc_time_set)(const struct scmi_protocol_handle *ph, u32 id,
+			    uint64_t sec);
+	int (*rtc_time_get)(const struct scmi_protocol_handle *ph, u32 id,
+			    u64 *val);
+	int (*rtc_alarm_set)(const struct scmi_protocol_handle *ph, u32 id,
+			     bool enable, u64 sec);
+	int (*button_get)(const struct scmi_protocol_handle *ph, u32 *state);
+};
+
+enum scmi_nxp_notification_events {
+	SCMI_EVENT_IMX_BBM_RTC = 0x0,
+	SCMI_EVENT_IMX_BBM_BUTTON = 0x1,
+};
+
+struct scmi_imx_bbm_notif_report {
+	bool			is_rtc;
+	bool			is_button;
+	ktime_t			timestamp;
+	unsigned int		rtc_id;
+	unsigned int		rtc_evt;
+};
+#endif