1 files changed, 379 insertions, 0 deletions

diff --git a/drivers/firmware/arm_scmi/voltage.c b/drivers/firmware/arm_scmi/voltage.c
new file mode 100644
index 0000000000..a3d78db28f
--- /dev/null
+++ b/drivers/firmware/arm_scmi/voltage.c
@@ -0,0 +1,379 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * System Control and Management Interface (SCMI) Voltage Protocol
+ *
+ * Copyright (C) 2020-2021 ARM Ltd.
+ */
+
+#include <common.h>
+#include <linux/scmi_protocol.h>
+
+#include "common.h"
+
+#define VOLTAGE_DOMS_NUM_MASK		GENMASK(15, 0)
+#define REMAINING_LEVELS_MASK		GENMASK(31, 16)
+#define RETURNED_LEVELS_MASK		GENMASK(11, 0)
+
+enum scmi_voltage_protocol_cmd {
+	VOLTAGE_DOMAIN_ATTRIBUTES = 0x3,
+	VOLTAGE_DESCRIBE_LEVELS = 0x4,
+	VOLTAGE_CONFIG_SET = 0x5,
+	VOLTAGE_CONFIG_GET = 0x6,
+	VOLTAGE_LEVEL_SET = 0x7,
+	VOLTAGE_LEVEL_GET = 0x8,
+};
+
+#define NUM_VOLTAGE_DOMAINS(x)	((u16)(FIELD_GET(VOLTAGE_DOMS_NUM_MASK, (x))))
+
+struct scmi_msg_resp_domain_attributes {
+	__le32 attr;
+	u8 name[SCMI_MAX_STR_SIZE];
+};
+
+struct scmi_msg_cmd_describe_levels {
+	__le32 domain_id;
+	__le32 level_index;
+};
+
+struct scmi_msg_resp_describe_levels {
+	__le32 flags;
+#define NUM_REMAINING_LEVELS(f)	((u16)(FIELD_GET(REMAINING_LEVELS_MASK, (f))))
+#define NUM_RETURNED_LEVELS(f)	((u16)(FIELD_GET(RETURNED_LEVELS_MASK, (f))))
+#define SUPPORTS_SEGMENTED_LEVELS(f)	((f) & BIT(12))
+	__le32 voltage[];
+};
+
+struct scmi_msg_cmd_config_set {
+	__le32 domain_id;
+	__le32 config;
+};
+
+struct scmi_msg_cmd_level_set {
+	__le32 domain_id;
+	__le32 flags;
+	__le32 voltage_level;
+};
+
+struct voltage_info {
+	unsigned int version;
+	unsigned int num_domains;
+	struct scmi_voltage_info *domains;
+};
+
+static int scmi_protocol_attributes_get(const struct scmi_protocol_handle *ph,
+					struct voltage_info *vinfo)
+{
+	int ret;
+	struct scmi_xfer *t;
+
+	ret = ph->xops->xfer_get_init(ph, PROTOCOL_ATTRIBUTES, 0,
+				      sizeof(__le32), &t);
+	if (ret)
+		return ret;
+
+	ret = ph->xops->do_xfer(ph, t);
+	if (!ret)
+		vinfo->num_domains =
+			NUM_VOLTAGE_DOMAINS(get_unaligned_le32(t->rx.buf));
+
+	ph->xops->xfer_put(ph, t);
+	return ret;
+}
+
+static int scmi_init_voltage_levels(struct device_d *dev,
+				    struct scmi_voltage_info *v,
+				    u32 num_returned, u32 num_remaining,
+				    bool segmented)
+{
+	u32 num_levels;
+
+	num_levels = num_returned + num_remaining;
+	/*
+	 * segmented levels entries are represented by a single triplet
+	 * returned all in one go.
+	 */
+	if (!num_levels ||
+	    (segmented && (num_remaining || num_returned != 3))) {
+		dev_err(dev,
+			"Invalid level descriptor(%d/%d/%d) for voltage dom %d\n",
+			num_levels, num_returned, num_remaining, v->id);
+		return -EINVAL;
+	}
+
+	v->levels_uv = kcalloc(num_levels, sizeof(u32), GFP_KERNEL);
+	if (!v->levels_uv)
+		return -ENOMEM;
+
+	v->num_levels = num_levels;
+	v->segmented = segmented;
+
+	return 0;
+}
+
+static int scmi_voltage_descriptors_get(const struct scmi_protocol_handle *ph,
+					struct voltage_info *vinfo)
+{
+	int ret, dom;
+	struct scmi_xfer *td, *tl;
+	struct device_d *dev = ph->dev;
+	struct scmi_msg_resp_domain_attributes *resp_dom;
+	struct scmi_msg_resp_describe_levels *resp_levels;
+
+	ret = ph->xops->xfer_get_init(ph, VOLTAGE_DOMAIN_ATTRIBUTES,
+				      sizeof(__le32), sizeof(*resp_dom), &td);
+	if (ret)
+		return ret;
+	resp_dom = td->rx.buf;
+
+	ret = ph->xops->xfer_get_init(ph, VOLTAGE_DESCRIBE_LEVELS,
+				      sizeof(__le64), 0, &tl);
+	if (ret)
+		goto outd;
+	resp_levels = tl->rx.buf;
+
+	for (dom = 0; dom < vinfo->num_domains; dom++) {
+		u32 desc_index = 0;
+		u16 num_returned = 0, num_remaining = 0;
+		struct scmi_msg_cmd_describe_levels *cmd;
+		struct scmi_voltage_info *v;
+
+		/* Retrieve domain attributes at first ... */
+		put_unaligned_le32(dom, td->tx.buf);
+		ret = ph->xops->do_xfer(ph, td);
+		/* Skip domain on comms error */
+		if (ret)
+			continue;
+
+		v = vinfo->domains + dom;
+		v->id = dom;
+		v->attributes = le32_to_cpu(resp_dom->attr);
+		strlcpy(v->name, resp_dom->name, SCMI_MAX_STR_SIZE);
+
+		cmd = tl->tx.buf;
+		/* ...then retrieve domain levels descriptions */
+		do {
+			u32 flags;
+			int cnt;
+
+			cmd->domain_id = cpu_to_le32(v->id);
+			cmd->level_index = desc_index;
+			ret = ph->xops->do_xfer(ph, tl);
+			if (ret)
+				break;
+
+			flags = le32_to_cpu(resp_levels->flags);
+			num_returned = NUM_RETURNED_LEVELS(flags);
+			num_remaining = NUM_REMAINING_LEVELS(flags);
+
+			/* Allocate space for num_levels if not already done */
+			if (!v->num_levels) {
+				ret = scmi_init_voltage_levels(dev, v,
+							       num_returned,
+							       num_remaining,
+					      SUPPORTS_SEGMENTED_LEVELS(flags));
+				if (ret)
+					break;
+			}
+
+			if (desc_index + num_returned > v->num_levels) {
+				dev_err(ph->dev,
+					"No. of voltage levels can't exceed %d\n",
+					v->num_levels);
+				ret = -EINVAL;
+				break;
+			}
+
+			for (cnt = 0; cnt < num_returned; cnt++) {
+				s32 val;
+
+				val =
+				    (s32)le32_to_cpu(resp_levels->voltage[cnt]);
+				v->levels_uv[desc_index + cnt] = val;
+				if (val < 0)
+					v->negative_volts_allowed = true;
+			}
+
+			desc_index += num_returned;
+
+			ph->xops->reset_rx_to_maxsz(ph, tl);
+			/* check both to avoid infinite loop due to buggy fw */
+		} while (num_returned && num_remaining);
+
+		if (ret) {
+			v->num_levels = 0;
+			kfree(v->levels_uv);
+		}
+
+		ph->xops->reset_rx_to_maxsz(ph, td);
+	}
+
+	ph->xops->xfer_put(ph, tl);
+outd:
+	ph->xops->xfer_put(ph, td);
+
+	return ret;
+}
+
+static int __scmi_voltage_get_u32(const struct scmi_protocol_handle *ph,
+				  u8 cmd_id, u32 domain_id, u32 *value)
+{
+	int ret;
+	struct scmi_xfer *t;
+	struct voltage_info *vinfo = ph->get_priv(ph);
+
+	if (domain_id >= vinfo->num_domains)
+		return -EINVAL;
+
+	ret = ph->xops->xfer_get_init(ph, cmd_id, sizeof(__le32), 0, &t);
+	if (ret)
+		return ret;
+
+	put_unaligned_le32(domain_id, t->tx.buf);
+	ret = ph->xops->do_xfer(ph, t);
+	if (!ret)
+		*value = get_unaligned_le32(t->rx.buf);
+
+	ph->xops->xfer_put(ph, t);
+	return ret;
+}
+
+static int scmi_voltage_config_set(const struct scmi_protocol_handle *ph,
+				   u32 domain_id, u32 config)
+{
+	int ret;
+	struct scmi_xfer *t;
+	struct voltage_info *vinfo = ph->get_priv(ph);
+	struct scmi_msg_cmd_config_set *cmd;
+
+	if (domain_id >= vinfo->num_domains)
+		return -EINVAL;
+
+	ret = ph->xops->xfer_get_init(ph, VOLTAGE_CONFIG_SET,
+				     sizeof(*cmd), 0, &t);
+	if (ret)
+		return ret;
+
+	cmd = t->tx.buf;
+	cmd->domain_id = cpu_to_le32(domain_id);
+	cmd->config = cpu_to_le32(config & GENMASK(3, 0));
+
+	ret = ph->xops->do_xfer(ph, t);
+
+	ph->xops->xfer_put(ph, t);
+	return ret;
+}
+
+static int scmi_voltage_config_get(const struct scmi_protocol_handle *ph,
+				   u32 domain_id, u32 *config)
+{
+	return __scmi_voltage_get_u32(ph, VOLTAGE_CONFIG_GET,
+				      domain_id, config);
+}
+
+static int scmi_voltage_level_set(const struct scmi_protocol_handle *ph,
+				  u32 domain_id, u32 flags, s32 volt_uV)
+{
+	int ret;
+	struct scmi_xfer *t;
+	struct voltage_info *vinfo = ph->get_priv(ph);
+	struct scmi_msg_cmd_level_set *cmd;
+
+	if (domain_id >= vinfo->num_domains)
+		return -EINVAL;
+
+	ret = ph->xops->xfer_get_init(ph, VOLTAGE_LEVEL_SET,
+				      sizeof(*cmd), 0, &t);
+	if (ret)
+		return ret;
+
+	cmd = t->tx.buf;
+	cmd->domain_id = cpu_to_le32(domain_id);
+	cmd->flags = cpu_to_le32(flags);
+	cmd->voltage_level = cpu_to_le32(volt_uV);
+
+	ret = ph->xops->do_xfer(ph, t);
+
+	ph->xops->xfer_put(ph, t);
+	return ret;
+}
+
+static int scmi_voltage_level_get(const struct scmi_protocol_handle *ph,
+				  u32 domain_id, s32 *volt_uV)
+{
+	return __scmi_voltage_get_u32(ph, VOLTAGE_LEVEL_GET,
+				      domain_id, (u32 *)volt_uV);
+}
+
+static const struct scmi_voltage_info * __must_check
+scmi_voltage_info_get(const struct scmi_protocol_handle *ph, u32 domain_id)
+{
+	struct voltage_info *vinfo = ph->get_priv(ph);
+
+	if (domain_id >= vinfo->num_domains ||
+	    !vinfo->domains[domain_id].num_levels)
+		return NULL;
+
+	return vinfo->domains + domain_id;
+}
+
+static int scmi_voltage_domains_num_get(const struct scmi_protocol_handle *ph)
+{
+	struct voltage_info *vinfo = ph->get_priv(ph);
+
+	return vinfo->num_domains;
+}
+
+static struct scmi_voltage_proto_ops voltage_proto_ops = {
+	.num_domains_get = scmi_voltage_domains_num_get,
+	.info_get = scmi_voltage_info_get,
+	.config_set = scmi_voltage_config_set,
+	.config_get = scmi_voltage_config_get,
+	.level_set = scmi_voltage_level_set,
+	.level_get = scmi_voltage_level_get,
+};
+
+static int scmi_voltage_protocol_init(const struct scmi_protocol_handle *ph)
+{
+	int ret;
+	u32 version;
+	struct voltage_info *vinfo;
+
+	ret = ph->xops->version_get(ph, &version);
+	if (ret)
+		return ret;
+
+	dev_dbg(ph->dev, "Voltage Version %d.%d\n",
+		PROTOCOL_REV_MAJOR(version), PROTOCOL_REV_MINOR(version));
+
+	vinfo = kzalloc(sizeof(*vinfo), GFP_KERNEL);
+	if (!vinfo)
+		return -ENOMEM;
+	vinfo->version = version;
+
+	ret = scmi_protocol_attributes_get(ph, vinfo);
+	if (ret)
+		return ret;
+
+	if (vinfo->num_domains) {
+		vinfo->domains = kcalloc(vinfo->num_domains,
+					      sizeof(*vinfo->domains),
+					      GFP_KERNEL);
+		if (!vinfo->domains)
+			return -ENOMEM;
+		ret = scmi_voltage_descriptors_get(ph, vinfo);
+		if (ret)
+			return ret;
+	} else {
+		dev_warn(ph->dev, "No Voltage domains found.\n");
+	}
+
+	return ph->set_priv(ph, vinfo);
+}
+
+static const struct scmi_protocol scmi_voltage = {
+	.id = SCMI_PROTOCOL_VOLTAGE,
+	.instance_init = &scmi_voltage_protocol_init,
+	.ops = &voltage_proto_ops,
+};
+
+DEFINE_SCMI_PROTOCOL_REGISTER(voltage, scmi_voltage)