1 files changed, 307 insertions, 0 deletions

diff --git a/sound/firewire/cmp.c b/sound/firewire/cmp.c
new file mode 100644
index 000000000000..14cacbc655dd
--- /dev/null
+++ b/sound/firewire/cmp.c
@@ -0,0 +1,307 @@
+/*
+ * 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);
+        int generation = c->resources.generation;
+        int rcode, errors = 0;
+        __be32 old_arg, buffer[2];
+        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);