1 files changed, 415 insertions, 0 deletions
diff --git a/sound/firewire/cmp.c b/sound/firewire/cmp.c
new file mode 100644
index 000000000..b596bec19
--- /dev/null
+++ b/sound/firewire/cmp.c
@@ -0,0 +1,415 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Connection Management Procedures (IEC 61883-1) helper functions
+ *
+ * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
+ */
+
+#include <linux/device.h>
+#include <linux/firewire.h>
+#include <linux/firewire-constants.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include "lib.h"
+#include "iso-resources.h"
+#include "cmp.h"
+
+/* MPR common fields */
+#define MPR_SPEED_MASK		0xc0000000
+#define MPR_SPEED_SHIFT		30
+#define MPR_XSPEED_MASK		0x00000060
+#define MPR_XSPEED_SHIFT	5
+#define MPR_PLUGS_MASK		0x0000001f
+
+/* PCR common fields */
+#define PCR_ONLINE		0x80000000
+#define PCR_BCAST_CONN		0x40000000
+#define PCR_P2P_CONN_MASK	0x3f000000
+#define PCR_P2P_CONN_SHIFT	24
+#define PCR_CHANNEL_MASK	0x003f0000
+#define PCR_CHANNEL_SHIFT	16
+
+/* oPCR specific fields */
+#define OPCR_XSPEED_MASK	0x00C00000
+#define OPCR_XSPEED_SHIFT	22
+#define OPCR_SPEED_MASK		0x0000C000
+#define OPCR_SPEED_SHIFT	14
+#define OPCR_OVERHEAD_ID_MASK	0x00003C00
+#define OPCR_OVERHEAD_ID_SHIFT	10
+
+enum bus_reset_handling {
+	ABORT_ON_BUS_RESET,
+	SUCCEED_ON_BUS_RESET,
+};
+
+static __printf(2, 3)
+void cmp_error(struct cmp_connection *c, const char *fmt, ...)
+{
+	va_list va;
+
+	va_start(va, fmt);
+	dev_err(&c->resources.unit->device, "%cPCR%u: %pV",
+		(c->direction == CMP_INPUT) ? 'i' : 'o',
+		c->pcr_index, &(struct va_format){ fmt, &va });
+	va_end(va);
+}
+
+static u64 mpr_address(struct cmp_connection *c)
+{
+	if (c->direction == CMP_INPUT)
+		return CSR_REGISTER_BASE + CSR_IMPR;
+	else
+		return CSR_REGISTER_BASE + CSR_OMPR;
+}
+
+static u64 pcr_address(struct cmp_connection *c)
+{
+	if (c->direction == CMP_INPUT)
+		return CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index);
+	else
+		return CSR_REGISTER_BASE + CSR_OPCR(c->pcr_index);
+}
+
+static int pcr_modify(struct cmp_connection *c,
+		      __be32 (*modify)(struct cmp_connection *c, __be32 old),
+		      int (*check)(struct cmp_connection *c, __be32 pcr),
+		      enum bus_reset_handling bus_reset_handling)
+{
+	__be32 old_arg, buffer[2];
+	int err;
+
+	buffer[0] = c->last_pcr_value;
+	for (;;) {
+		old_arg = buffer[0];
+		buffer[1] = modify(c, buffer[0]);
+
+		err = snd_fw_transaction(
+				c->resources.unit, TCODE_LOCK_COMPARE_SWAP,
+				pcr_address(c), buffer, 8,
+				FW_FIXED_GENERATION | c->resources.generation);
+
+		if (err < 0) {
+			if (err == -EAGAIN &&
+			    bus_reset_handling == SUCCEED_ON_BUS_RESET)
+				err = 0;
+			return err;
+		}
+
+		if (buffer[0] == old_arg) /* success? */
+			break;
+
+		if (check) {
+			err = check(c, buffer[0]);
+			if (err < 0)
+				return err;
+		}
+	}
+	c->last_pcr_value = buffer[1];
+
+	return 0;
+}
+
+
+/**
+ * cmp_connection_init - initializes a connection manager
+ * @c: the connection manager to initialize
+ * @unit: a unit of the target device
+ * @direction: input or output
+ * @pcr_index: the index of the iPCR/oPCR on the target device
+ */
+int cmp_connection_init(struct cmp_connection *c,
+			struct fw_unit *unit,
+			enum cmp_direction direction,
+			unsigned int pcr_index)
+{
+	__be32 mpr_be;
+	u32 mpr;
+	int err;
+
+	c->direction = direction;
+	err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
+				 mpr_address(c), &mpr_be, 4, 0);
+	if (err < 0)
+		return err;
+	mpr = be32_to_cpu(mpr_be);
+
+	if (pcr_index >= (mpr & MPR_PLUGS_MASK))
+		return -EINVAL;
+
+	err = fw_iso_resources_init(&c->resources, unit);
+	if (err < 0)
+		return err;
+
+	c->connected = false;
+	mutex_init(&c->mutex);
+	c->last_pcr_value = cpu_to_be32(0x80000000);
+	c->pcr_index = pcr_index;
+	c->max_speed = (mpr & MPR_SPEED_MASK) >> MPR_SPEED_SHIFT;
+	if (c->max_speed == SCODE_BETA)
+		c->max_speed += (mpr & MPR_XSPEED_MASK) >> MPR_XSPEED_SHIFT;
+
+	return 0;
+}
+EXPORT_SYMBOL(cmp_connection_init);
+
+/**
+ * cmp_connection_check_used - check connection is already esablished or not
+ * @c: the connection manager to be checked
+ * @used: the pointer to store the result of checking the connection
+ */
+int cmp_connection_check_used(struct cmp_connection *c, bool *used)
+{
+	__be32 pcr;
+	int err;
+
+	err = snd_fw_transaction(
+			c->resources.unit, TCODE_READ_QUADLET_REQUEST,
+			pcr_address(c), &pcr, 4, 0);
+	if (err >= 0)
+		*used = !!(pcr & cpu_to_be32(PCR_BCAST_CONN |
+					     PCR_P2P_CONN_MASK));
+
+	return err;
+}
+EXPORT_SYMBOL(cmp_connection_check_used);
+
+/**
+ * cmp_connection_destroy - free connection manager resources
+ * @c: the connection manager
+ */
+void cmp_connection_destroy(struct cmp_connection *c)
+{
+	WARN_ON(c->connected);
+	mutex_destroy(&c->mutex);
+	fw_iso_resources_destroy(&c->resources);
+}
+EXPORT_SYMBOL(cmp_connection_destroy);
+
+int cmp_connection_reserve(struct cmp_connection *c,
+			   unsigned int max_payload_bytes)
+{
+	int err;
+
+	mutex_lock(&c->mutex);
+
+	if (WARN_ON(c->resources.allocated)) {
+		err = -EBUSY;
+		goto end;
+	}
+
+	c->speed = min(c->max_speed,
+		       fw_parent_device(c->resources.unit)->max_speed);
+
+	err = fw_iso_resources_allocate(&c->resources, max_payload_bytes,
+					c->speed);
+end:
+	mutex_unlock(&c->mutex);
+
+	return err;
+}
+EXPORT_SYMBOL(cmp_connection_reserve);
+
+void cmp_connection_release(struct cmp_connection *c)
+{
+	mutex_lock(&c->mutex);
+	fw_iso_resources_free(&c->resources);
+	mutex_unlock(&c->mutex);
+}
+EXPORT_SYMBOL(cmp_connection_release);
+
+static __be32 ipcr_set_modify(struct cmp_connection *c, __be32 ipcr)
+{
+	ipcr &= ~cpu_to_be32(PCR_BCAST_CONN |
+			     PCR_P2P_CONN_MASK |
+			     PCR_CHANNEL_MASK);
+	ipcr |= cpu_to_be32(1 << PCR_P2P_CONN_SHIFT);
+	ipcr |= cpu_to_be32(c->resources.channel << PCR_CHANNEL_SHIFT);
+
+	return ipcr;
+}
+
+static int get_overhead_id(struct cmp_connection *c)
+{
+	int id;
+
+	/*
+	 * apply "oPCR overhead ID encoding"
+	 * the encoding table can convert up to 512.
+	 * here the value over 512 is converted as the same way as 512.
+	 */
+	for (id = 1; id < 16; id++) {
+		if (c->resources.bandwidth_overhead < (id << 5))
+			break;
+	}
+	if (id == 16)
+		id = 0;
+
+	return id;
+}
+
+static __be32 opcr_set_modify(struct cmp_connection *c, __be32 opcr)
+{
+	unsigned int spd, xspd;
+
+	/* generate speed and extended speed field value */
+	if (c->speed > SCODE_400) {
+		spd  = SCODE_800;
+		xspd = c->speed - SCODE_800;
+	} else {
+		spd = c->speed;
+		xspd = 0;
+	}
+
+	opcr &= ~cpu_to_be32(PCR_BCAST_CONN |
+			     PCR_P2P_CONN_MASK |
+			     OPCR_XSPEED_MASK |
+			     PCR_CHANNEL_MASK |
+			     OPCR_SPEED_MASK |
+			     OPCR_OVERHEAD_ID_MASK);
+	opcr |= cpu_to_be32(1 << PCR_P2P_CONN_SHIFT);
+	opcr |= cpu_to_be32(xspd << OPCR_XSPEED_SHIFT);
+	opcr |= cpu_to_be32(c->resources.channel << PCR_CHANNEL_SHIFT);
+	opcr |= cpu_to_be32(spd << OPCR_SPEED_SHIFT);
+	opcr |= cpu_to_be32(get_overhead_id(c) << OPCR_OVERHEAD_ID_SHIFT);
+
+	return opcr;
+}
+
+static int pcr_set_check(struct cmp_connection *c, __be32 pcr)
+{
+	if (pcr & cpu_to_be32(PCR_BCAST_CONN |
+			      PCR_P2P_CONN_MASK)) {
+		cmp_error(c, "plug is already in use\n");
+		return -EBUSY;
+	}
+	if (!(pcr & cpu_to_be32(PCR_ONLINE))) {
+		cmp_error(c, "plug is not on-line\n");
+		return -ECONNREFUSED;
+	}
+
+	return 0;
+}
+
+/**
+ * cmp_connection_establish - establish a connection to the target
+ * @c: the connection manager
+ *
+ * This function establishes a point-to-point connection from the local
+ * computer to the target by allocating isochronous resources (channel and
+ * bandwidth) and setting the target's input/output plug control register.
+ * When this function succeeds, the caller is responsible for starting
+ * transmitting packets.
+ */
+int cmp_connection_establish(struct cmp_connection *c)
+{
+	int err;
+
+	mutex_lock(&c->mutex);
+
+	if (WARN_ON(c->connected)) {
+		mutex_unlock(&c->mutex);
+		return -EISCONN;
+	}
+
+retry_after_bus_reset:
+	if (c->direction == CMP_OUTPUT)
+		err = pcr_modify(c, opcr_set_modify, pcr_set_check,
+				 ABORT_ON_BUS_RESET);
+	else
+		err = pcr_modify(c, ipcr_set_modify, pcr_set_check,
+				 ABORT_ON_BUS_RESET);
+
+	if (err == -EAGAIN) {
+		err = fw_iso_resources_update(&c->resources);
+		if (err >= 0)
+			goto retry_after_bus_reset;
+	}
+	if (err >= 0)
+		c->connected = true;
+
+	mutex_unlock(&c->mutex);
+
+	return err;
+}
+EXPORT_SYMBOL(cmp_connection_establish);
+
+/**
+ * cmp_connection_update - update the connection after a bus reset
+ * @c: the connection manager
+ *
+ * This function must be called from the driver's .update handler to
+ * reestablish any connection that might have been active.
+ *
+ * Returns zero on success, or a negative error code.  On an error, the
+ * connection is broken and the caller must stop transmitting iso packets.
+ */
+int cmp_connection_update(struct cmp_connection *c)
+{
+	int err;
+
+	mutex_lock(&c->mutex);
+
+	if (!c->connected) {
+		mutex_unlock(&c->mutex);
+		return 0;
+	}
+
+	err = fw_iso_resources_update(&c->resources);
+	if (err < 0)
+		goto err_unconnect;
+
+	if (c->direction == CMP_OUTPUT)
+		err = pcr_modify(c, opcr_set_modify, pcr_set_check,
+				 SUCCEED_ON_BUS_RESET);
+	else
+		err = pcr_modify(c, ipcr_set_modify, pcr_set_check,
+				 SUCCEED_ON_BUS_RESET);
+
+	if (err < 0)
+		goto err_unconnect;
+
+	mutex_unlock(&c->mutex);
+
+	return 0;
+
+err_unconnect:
+	c->connected = false;
+	mutex_unlock(&c->mutex);
+
+	return err;
+}
+EXPORT_SYMBOL(cmp_connection_update);
+
+static __be32 pcr_break_modify(struct cmp_connection *c, __be32 pcr)
+{
+	return pcr & ~cpu_to_be32(PCR_BCAST_CONN | PCR_P2P_CONN_MASK);
+}
+
+/**
+ * cmp_connection_break - break the connection to the target
+ * @c: the connection manager
+ *
+ * This function deactives the connection in the target's input/output plug
+ * control register, and frees the isochronous resources of the connection.
+ * Before calling this function, the caller should cease transmitting packets.
+ */
+void cmp_connection_break(struct cmp_connection *c)
+{
+	int err;
+
+	mutex_lock(&c->mutex);
+
+	if (!c->connected) {
+		mutex_unlock(&c->mutex);
+		return;
+	}
+
+	err = pcr_modify(c, pcr_break_modify, NULL, SUCCEED_ON_BUS_RESET);
+	if (err < 0)
+		cmp_error(c, "plug is still connected\n");
+
+	c->connected = false;
+
+	mutex_unlock(&c->mutex);
+}
+EXPORT_SYMBOL(cmp_connection_break);