// 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);