1 files changed, 302 insertions, 0 deletions
diff --git a/drivers/hwtracing/stm/p_sys-t.c b/drivers/hwtracing/stm/p_sys-t.c
new file mode 100644
index 000000000000..ffeb057b777c
--- /dev/null
+++ b/drivers/hwtracing/stm/p_sys-t.c
@@ -0,0 +1,302 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MIPI SyS-T framing protocol for STM devices.
+ * Copyright (c) 2018, Intel Corporation.
+ */
+
+#include <linux/configfs.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/uuid.h>
+#include <linux/stm.h>
+#include "stm.h"
+
+enum sys_t_message_type {
+	MIPI_SYST_TYPE_BUILD	= 0,
+	MIPI_SYST_TYPE_SHORT32,
+	MIPI_SYST_TYPE_STRING,
+	MIPI_SYST_TYPE_CATALOG,
+	MIPI_SYST_TYPE_RAW	= 6,
+	MIPI_SYST_TYPE_SHORT64,
+	MIPI_SYST_TYPE_CLOCK,
+};
+
+enum sys_t_message_severity {
+	MIPI_SYST_SEVERITY_MAX	= 0,
+	MIPI_SYST_SEVERITY_FATAL,
+	MIPI_SYST_SEVERITY_ERROR,
+	MIPI_SYST_SEVERITY_WARNING,
+	MIPI_SYST_SEVERITY_INFO,
+	MIPI_SYST_SEVERITY_USER1,
+	MIPI_SYST_SEVERITY_USER2,
+	MIPI_SYST_SEVERITY_DEBUG,
+};
+
+enum sys_t_message_build_subtype {
+	MIPI_SYST_BUILD_ID_COMPACT32 = 0,
+	MIPI_SYST_BUILD_ID_COMPACT64,
+	MIPI_SYST_BUILD_ID_LONG,
+};
+
+enum sys_t_message_clock_subtype {
+	MIPI_SYST_CLOCK_TRANSPORT_SYNC = 1,
+};
+
+enum sys_t_message_string_subtype {
+	MIPI_SYST_STRING_GENERIC	= 1,
+	MIPI_SYST_STRING_FUNCTIONENTER,
+	MIPI_SYST_STRING_FUNCTIONEXIT,
+	MIPI_SYST_STRING_INVALIDPARAM	= 5,
+	MIPI_SYST_STRING_ASSERT		= 7,
+	MIPI_SYST_STRING_PRINTF_32	= 11,
+	MIPI_SYST_STRING_PRINTF_64	= 12,
+};
+
+#define MIPI_SYST_TYPE(t)		((u32)(MIPI_SYST_TYPE_ ## t))
+#define MIPI_SYST_SEVERITY(s)		((u32)(MIPI_SYST_SEVERITY_ ## s) << 4)
+#define MIPI_SYST_OPT_LOC		BIT(8)
+#define MIPI_SYST_OPT_LEN		BIT(9)
+#define MIPI_SYST_OPT_CHK		BIT(10)
+#define MIPI_SYST_OPT_TS		BIT(11)
+#define MIPI_SYST_UNIT(u)		((u32)(u) << 12)
+#define MIPI_SYST_ORIGIN(o)		((u32)(o) << 16)
+#define MIPI_SYST_OPT_GUID		BIT(23)
+#define MIPI_SYST_SUBTYPE(s)		((u32)(MIPI_SYST_ ## s) << 24)
+#define MIPI_SYST_UNITLARGE(u)		(MIPI_SYST_UNIT(u & 0xf) | \
+					 MIPI_SYST_ORIGIN(u >> 4))
+#define MIPI_SYST_TYPES(t, s)		(MIPI_SYST_TYPE(t) | \
+					 MIPI_SYST_SUBTYPE(t ## _ ## s))
+
+#define DATA_HEADER	(MIPI_SYST_TYPES(STRING, GENERIC)	| \
+			 MIPI_SYST_SEVERITY(INFO)		| \
+			 MIPI_SYST_OPT_GUID)
+
+struct sys_t_policy_node {
+	uuid_t		uuid;
+	bool		do_len;
+	unsigned long	ts_interval;
+};
+
+struct sys_t_output {
+	struct sys_t_policy_node	node;
+	unsigned long	ts_jiffies;
+};
+
+static void sys_t_policy_node_init(void *priv)
+{
+	struct sys_t_policy_node *pn = priv;
+
+	generate_random_uuid(pn->uuid.b);
+}
+
+static int sys_t_output_open(void *priv, struct stm_output *output)
+{
+	struct sys_t_policy_node *pn = priv;
+	struct sys_t_output *opriv;
+
+	opriv = kzalloc(sizeof(*opriv), GFP_ATOMIC);
+	if (!opriv)
+		return -ENOMEM;
+
+	memcpy(&opriv->node, pn, sizeof(opriv->node));
+	output->pdrv_private = opriv;
+
+	return 0;
+}
+
+static void sys_t_output_close(struct stm_output *output)
+{
+	kfree(output->pdrv_private);
+}
+
+static ssize_t sys_t_policy_uuid_show(struct config_item *item,
+				      char *page)
+{
+	struct sys_t_policy_node *pn = to_pdrv_policy_node(item);
+
+	return sprintf(page, "%pU\n", &pn->uuid);
+}
+
+static ssize_t
+sys_t_policy_uuid_store(struct config_item *item, const char *page,
+			size_t count)
+{
+	struct mutex *mutexp = &item->ci_group->cg_subsys->su_mutex;
+	struct sys_t_policy_node *pn = to_pdrv_policy_node(item);
+	int ret;
+
+	mutex_lock(mutexp);
+	ret = uuid_parse(page, &pn->uuid);
+	mutex_unlock(mutexp);
+
+	return ret < 0 ? ret : count;
+}
+
+CONFIGFS_ATTR(sys_t_policy_, uuid);
+
+static ssize_t sys_t_policy_do_len_show(struct config_item *item,
+				      char *page)
+{
+	struct sys_t_policy_node *pn = to_pdrv_policy_node(item);
+
+	return sprintf(page, "%d\n", pn->do_len);
+}
+
+static ssize_t
+sys_t_policy_do_len_store(struct config_item *item, const char *page,
+			size_t count)
+{
+	struct mutex *mutexp = &item->ci_group->cg_subsys->su_mutex;
+	struct sys_t_policy_node *pn = to_pdrv_policy_node(item);
+	int ret;
+
+	mutex_lock(mutexp);
+	ret = kstrtobool(page, &pn->do_len);
+	mutex_unlock(mutexp);
+
+	return ret ? ret : count;
+}
+
+CONFIGFS_ATTR(sys_t_policy_, do_len);
+
+static ssize_t sys_t_policy_ts_interval_show(struct config_item *item,
+					     char *page)
+{
+	struct sys_t_policy_node *pn = to_pdrv_policy_node(item);
+
+	return sprintf(page, "%u\n", jiffies_to_msecs(pn->ts_interval));
+}
+
+static ssize_t
+sys_t_policy_ts_interval_store(struct config_item *item, const char *page,
+			       size_t count)
+{
+	struct mutex *mutexp = &item->ci_group->cg_subsys->su_mutex;
+	struct sys_t_policy_node *pn = to_pdrv_policy_node(item);
+	unsigned int ms;
+	int ret;
+
+	mutex_lock(mutexp);
+	ret = kstrtouint(page, 10, &ms);
+	mutex_unlock(mutexp);
+
+	if (!ret) {
+		pn->ts_interval = msecs_to_jiffies(ms);
+		return count;
+	}
+
+	return ret;
+}
+
+CONFIGFS_ATTR(sys_t_policy_, ts_interval);
+
+static struct configfs_attribute *sys_t_policy_attrs[] = {
+	&sys_t_policy_attr_uuid,
+	&sys_t_policy_attr_do_len,
+	&sys_t_policy_attr_ts_interval,
+	NULL,
+};
+
+static inline bool sys_t_need_ts(struct sys_t_output *op)
+{
+	if (op->node.ts_interval &&
+	    time_after(op->ts_jiffies + op->node.ts_interval, jiffies)) {
+		op->ts_jiffies = jiffies;
+
+		return true;
+	}
+
+	return false;
+}
+
+static ssize_t sys_t_write(struct stm_data *data, struct stm_output *output,
+			   unsigned int chan, const char *buf, size_t count)
+{
+	struct sys_t_output *op = output->pdrv_private;
+	unsigned int c = output->channel + chan;
+	unsigned int m = output->master;
+	const unsigned char nil = 0;
+	u32 header = DATA_HEADER;
+	ssize_t sz;
+
+	/* We require an existing policy node to proceed */
+	if (!op)
+		return -EINVAL;
+
+	if (op->node.do_len)
+		header |= MIPI_SYST_OPT_LEN;
+	if (sys_t_need_ts(op))
+		header |= MIPI_SYST_OPT_TS;
+
+	/*
+	 * STP framing rules for SyS-T frames:
+	 *   * the first packet of the SyS-T frame is timestamped;
+	 *   * the last packet is a FLAG.
+	 */
+	/* Message layout: HEADER / GUID / [LENGTH /][TIMESTAMP /] DATA */
+	/* HEADER */
+	sz = data->packet(data, m, c, STP_PACKET_DATA, STP_PACKET_TIMESTAMPED,
+			  4, (u8 *)&header);
+	if (sz <= 0)
+		return sz;
+
+	/* GUID */
+	sz = stm_data_write(data, m, c, false, op->node.uuid.b, UUID_SIZE);
+	if (sz <= 0)
+		return sz;
+
+	/* [LENGTH] */
+	if (op->node.do_len) {
+		u16 length = count;
+
+		sz = data->packet(data, m, c, STP_PACKET_DATA, 0, 2,
+				  (u8 *)&length);
+		if (sz <= 0)
+			return sz;
+	}
+
+	/* [TIMESTAMP] */
+	if (header & MIPI_SYST_OPT_TS) {
+		u64 ts = ktime_get_real_ns();
+
+		sz = stm_data_write(data, m, c, false, &ts, sizeof(ts));
+		if (sz <= 0)
+			return sz;
+	}
+
+	/* DATA */
+	sz = stm_data_write(data, m, c, false, buf, count);
+	if (sz > 0)
+		data->packet(data, m, c, STP_PACKET_FLAG, 0, 0, &nil);
+
+	return sz;
+}
+
+static const struct stm_protocol_driver sys_t_pdrv = {
+	.owner			= THIS_MODULE,
+	.name			= "p_sys-t",
+	.priv_sz		= sizeof(struct sys_t_policy_node),
+	.write			= sys_t_write,
+	.policy_attr		= sys_t_policy_attrs,
+	.policy_node_init	= sys_t_policy_node_init,
+	.output_open		= sys_t_output_open,
+	.output_close		= sys_t_output_close,
+};
+
+static int sys_t_stm_init(void)
+{
+	return stm_register_protocol(&sys_t_pdrv);
+}
+
+static void sys_t_stm_exit(void)
+{
+	stm_unregister_protocol(&sys_t_pdrv);
+}
+
+module_init(sys_t_stm_init);
+module_exit(sys_t_stm_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MIPI SyS-T STM framing protocol driver");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");