1 files changed, 308 insertions, 0 deletions
diff --git a/sound/firewire/cmp.c b/sound/firewire/cmp.c
new file mode 100644
index 0000000..4a37f3a
--- /dev/null
+++ b/sound/firewire/cmp.c
@@ -0,0 +1,308 @@
+/*
+ * Connection Management Procedures (IEC 61883-1) helper functions
+ *
+ * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+#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"
+
+#define IMPR_SPEED_MASK		0xc0000000
+#define IMPR_SPEED_SHIFT	30
+#define IMPR_XSPEED_MASK	0x00000060
+#define IMPR_XSPEED_SHIFT	5
+#define IMPR_PLUGS_MASK		0x0000001f
+
+#define IPCR_ONLINE		0x80000000
+#define IPCR_BCAST_CONN		0x40000000
+#define IPCR_P2P_CONN_MASK	0x3f000000
+#define IPCR_P2P_CONN_SHIFT	24
+#define IPCR_CHANNEL_MASK	0x003f0000
+#define IPCR_CHANNEL_SHIFT	16
+
+enum bus_reset_handling {
+	ABORT_ON_BUS_RESET,
+	SUCCEED_ON_BUS_RESET,
+};
+
+static __attribute__((format(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",
+		'i', c->pcr_index, &(struct va_format){ fmt, &va });
+	va_end(va);
+}
+
+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)
+{
+	struct fw_device *device = fw_parent_device(c->resources.unit);
+	__be32 *buffer = c->resources.buffer;
+	int generation = c->resources.generation;
+	int rcode, errors = 0;
+	__be32 old_arg;
+	int err;
+
+	buffer[0] = c->last_pcr_value;
+	for (;;) {
+		old_arg = buffer[0];
+		buffer[1] = modify(c, buffer[0]);
+
+		rcode = fw_run_transaction(
+				device->card, TCODE_LOCK_COMPARE_SWAP,
+				device->node_id, generation, device->max_speed,
+				CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index),
+				buffer, 8);
+
+		if (rcode == RCODE_COMPLETE) {
+			if (buffer[0] == old_arg) /* success? */
+				break;
+
+			if (check) {
+				err = check(c, buffer[0]);
+				if (err < 0)
+					return err;
+			}
+		} else if (rcode == RCODE_GENERATION)
+			goto bus_reset;
+		else if (rcode_is_permanent_error(rcode) || ++errors >= 3)
+			goto io_error;
+	}
+	c->last_pcr_value = buffer[1];
+
+	return 0;
+
+io_error:
+	cmp_error(c, "transaction failed: %s\n", rcode_string(rcode));
+	return -EIO;
+
+bus_reset:
+	return bus_reset_handling == ABORT_ON_BUS_RESET ? -EAGAIN : 0;
+}
+
+
+/**
+ * cmp_connection_init - initializes a connection manager
+ * @c: the connection manager to initialize
+ * @unit: a unit of the target device
+ * @ipcr_index: the index of the iPCR on the target device
+ */
+int cmp_connection_init(struct cmp_connection *c,
+			struct fw_unit *unit,
+			unsigned int ipcr_index)
+{
+	__be32 impr_be;
+	u32 impr;
+	int err;
+
+	err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
+				 CSR_REGISTER_BASE + CSR_IMPR,
+				 &impr_be, 4);
+	if (err < 0)
+		return err;
+	impr = be32_to_cpu(impr_be);
+
+	if (ipcr_index >= (impr & IMPR_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 = ipcr_index;
+	c->max_speed = (impr & IMPR_SPEED_MASK) >> IMPR_SPEED_SHIFT;
+	if (c->max_speed == SCODE_BETA)
+		c->max_speed += (impr & IMPR_XSPEED_MASK) >> IMPR_XSPEED_SHIFT;
+
+	return 0;
+}
+EXPORT_SYMBOL(cmp_connection_init);
+
+/**
+ * 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);
+
+
+static __be32 ipcr_set_modify(struct cmp_connection *c, __be32 ipcr)
+{
+	ipcr &= ~cpu_to_be32(IPCR_BCAST_CONN |
+			     IPCR_P2P_CONN_MASK |
+			     IPCR_CHANNEL_MASK);
+	ipcr |= cpu_to_be32(1 << IPCR_P2P_CONN_SHIFT);
+	ipcr |= cpu_to_be32(c->resources.channel << IPCR_CHANNEL_SHIFT);
+
+	return ipcr;
+}
+
+static int ipcr_set_check(struct cmp_connection *c, __be32 ipcr)
+{
+	if (ipcr & cpu_to_be32(IPCR_BCAST_CONN |
+			       IPCR_P2P_CONN_MASK)) {
+		cmp_error(c, "plug is already in use\n");
+		return -EBUSY;
+	}
+	if (!(ipcr & cpu_to_be32(IPCR_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
+ * @max_payload_bytes: the amount of data (including CIP headers) per packet
+ *
+ * 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 plug control register.  When this
+ * function succeeds, the caller is responsible for starting transmitting
+ * packets.
+ */
+int cmp_connection_establish(struct cmp_connection *c,
+			     unsigned int max_payload_bytes)
+{
+	int err;
+
+	if (WARN_ON(c->connected))
+		return -EISCONN;
+
+	c->speed = min(c->max_speed,
+		       fw_parent_device(c->resources.unit)->max_speed);
+
+	mutex_lock(&c->mutex);
+
+retry_after_bus_reset:
+	err = fw_iso_resources_allocate(&c->resources,
+					max_payload_bytes, c->speed);
+	if (err < 0)
+		goto err_mutex;
+
+	err = pcr_modify(c, ipcr_set_modify, ipcr_set_check,
+			 ABORT_ON_BUS_RESET);
+	if (err == -EAGAIN) {
+		fw_iso_resources_free(&c->resources);
+		goto retry_after_bus_reset;
+	}
+	if (err < 0)
+		goto err_resources;
+
+	c->connected = true;
+
+	mutex_unlock(&c->mutex);
+
+	return 0;
+
+err_resources:
+	fw_iso_resources_free(&c->resources);
+err_mutex:
+	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;
+
+	err = pcr_modify(c, ipcr_set_modify, ipcr_set_check,
+			 SUCCEED_ON_BUS_RESET);
+	if (err < 0)
+		goto err_resources;
+
+	mutex_unlock(&c->mutex);
+
+	return 0;
+
+err_resources:
+	fw_iso_resources_free(&c->resources);
+err_unconnect:
+	c->connected = false;
+	mutex_unlock(&c->mutex);
+
+	return err;
+}
+EXPORT_SYMBOL(cmp_connection_update);
+
+
+static __be32 ipcr_break_modify(struct cmp_connection *c, __be32 ipcr)
+{
+	return ipcr & ~cpu_to_be32(IPCR_BCAST_CONN | IPCR_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 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, ipcr_break_modify, NULL, SUCCEED_ON_BUS_RESET);
+	if (err < 0)
+		cmp_error(c, "plug is still connected\n");
+
+	fw_iso_resources_free(&c->resources);
+
+	c->connected = false;
+
+	mutex_unlock(&c->mutex);
+}
+EXPORT_SYMBOL(cmp_connection_break);