| // 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); |
| |
| |
| 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); |