diff options
Diffstat (limited to 'kernel/sound/firewire/cmp.c')
| -rw-r--r-- | kernel/sound/firewire/cmp.c | 404 |
1 files changed, 404 insertions, 0 deletions
diff --git a/kernel/sound/firewire/cmp.c b/kernel/sound/firewire/cmp.c new file mode 100644 index 000000000..ae3bc1940 --- /dev/null +++ b/kernel/sound/firewire/cmp.c @@ -0,0 +1,404 @@ +/* + * 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); |