--- /dev/null
+/*
+ * 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"
+
+/* 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);
+
+
+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
+ * @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/output 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;
+
+ 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) {
+ 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;
+
+ 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_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 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");
+
+ fw_iso_resources_free(&c->resources);
+
+ c->connected = false;
+
+ mutex_unlock(&c->mutex);
+}
+EXPORT_SYMBOL(cmp_connection_break);
Code Review / kvmfornfv.git / blobdiff