Using control bus communication to accelerate link negotiation
Systems and methods for devices connected by a control bus to share configuration data for accelerating physical link negotiation for a peripheral interface are described. Computer devices, such as data storage devices, may include a peripheral interface configured to connect to a host system and a control bus interface to connect to a control bus. Other devices on the same control bus may establish peer communication through the control bus interface to share configuration data, such as coefficients for physical link negotiation of the peripheral interface. To accelerate reestablishing communication through the peripheral interface, the device may receive previously stored configuration data from another device over the control bus.
1 . A system, comprising:
a first data storage device comprising:
a peripheral interface configured to connect to a host system through a peripheral interface bus using a peripheral interface protocol, wherein the first data storage device is configured to receive storage communication through the peripheral interface;
a control bus interface configured to connect to a control bus using a control bus protocol, wherein at least a second device is configured to connect to the control bus using the control bus protocol;
a control bus messaging service configured to establish control bus communication between the first data storage device and the second device over the control bus and using the control bus protocol, wherein the first data storage device is configured to, during data storage device initialization, establish control bus communication with the second device prior to establishing storage communication through the peripheral interface;
a configuration service configured to, responsive to a loss of connection event for the peripheral interface, receive, through the control bus interface and from the second device, configuration data for the peripheral interface protocol; and
a link state machine configured to reestablish, using the configuration data received from the second device, communication through the peripheral interface to the host system.
2 . The system of claim 1 , wherein:
the control bus messaging service is further configured to:
send, to the second device and during a first operating period, a first peer message including the configuration data; and
send, to the second device and during a second operating period, a second peer message to request the configuration data;
the configuration service is further configured to determine, based on establishing communication through the peripheral interface to the host system during the first operating period, the configuration data;
the second operating period is after the first operating period and responsive to the loss of connection event; and
reestablishing communication through the peripheral interface is during the second operating period.
3 . The system of claim 2 , wherein the loss of connection event for the peripheral interface is selected from:
a power cycling event;
a cold boot event;
a reboot event;
a reset event;
a power state change event; and
a link error event.
4 . The system of claim 1 , wherein:
the control bus messaging service is further configured to:
establish communication with a plurality of connected devices including the second device; and
broadcast, to the plurality of connected devices, a first peer message including the configuration data; and
each connected device of the plurality of connected devices is configured to store the configuration data.
5 . The system of claim 4 , wherein:
the first data storage device and each connected device of the plurality of connected devices are configured to store a connected device registry;
each connected device registry includes connected device entries corresponding to each other device of the plurality of connected devices and the first data storage device; and
each connected device entry includes:
a connected device identifier; and
corresponding configuration data.
6 . The system of claim 1 , wherein:
the configuration data comprises a set of coefficient values for physical link training; and
the link state machine is further configured to negotiate, using the configuration data, physical link training between the first data storage device and the host system according to the peripheral interface protocol to reestablish communication through the peripheral interface.
7 . The system of claim 6 , wherein the set of coefficient values comprises coefficient presets for physical link filter values selected from a plurality of coefficient presets defined by the peripheral interface protocol.
8 . The system of claim 1 , further comprising:
a plurality of data storage devices configured for:
storage communication with the host system through the peripheral interface bus using the peripheral interface protocol; and
peer data storage device communication with each other data storage device of the plurality of data storage devices through the control bus using the control bus protocol, wherein:
the plurality of data storage devices includes the first data storage device; and
the second device is a second data storage device of the plurality of data storage devices.
9 . The system of claim 1 , wherein the second device is selected from:
the host system comprising:
a host control bus interface configured for control bus communication with the first data storage device through the control bus using the control bus protocol; and
a basic input output system configured to store the configuration data from a prior operating period for the first data storage device; and
a baseboard management controller comprising:
a management control bus interface configured for control bus communication with the first data storage device through the control bus using the control bus protocol; and
a management memory configured to store the configuration data from a prior operating period for the first data storage device.
10 . The system of claim 1 , further comprising:
a plurality of data storage devices configured for:
storage communication with the host system through the peripheral interface bus using the peripheral interface protocol; and
control bus communication with the host system through the control bus using the control bus protocol, wherein, during data storage device initialization, control bus communication is established prior to storage communication; and
the host system comprising:
a host control bus interface configured for control bus communication with the plurality of data storage devices through the control bus using the control bus protocol; and
a memory configured to store, for each data storage device of the plurality of data storage devices, configuration data from a prior operating period for that data storage device, wherein:
the plurality of data storage devices includes the first data storage device; and
the second device is the host system.
11 . A method, comprising:
establishing, by a first data storage device, control bus communication between the first data storage device and a second device over a control bus and using a control bus protocol;
initiating, by the first data storage device, storage communication between the first data storage device and a host system through a peripheral interface to a peripheral interface bus and using a peripheral interface protocol, wherein, during data storage device initialization, the first data storage device establishes control bus communication with the second device prior to establishing storage communication with the host system;
receiving, by the first data storage device and responsive to a loss of connection event for the peripheral interface, configuration data for the peripheral interface protocol from the second device over the control bus; and
reestablishing, by the first data storage device and using the configuration data received from the second device, storage communication through the peripheral interface to the host system.
12 . The method of claim 11 , further comprising:
determining, by the first data storage device and based on establishing storage communication through the peripheral interface to the host system during a first operating period, the configuration data;
establishing, by the first data storage device, communication with the second device over the control bus during the first operating period;
sending, from the first data storage device to the second device and during the first operating period, a first peer message including the configuration data; and
sending, from the first data storage device to the second device and during a second operating period, a second peer message to request the configuration data, wherein:
the second operating period is after the first operating period and responsive to the loss of connection event; and
reestablishing communication through the peripheral interface is during the second operating period.
13 . The method of claim 12 , further comprising:
determining, by the first data storage device, the loss of connection event for the peripheral interface, wherein the loss of connection event is selected from:
a power cycling event;
a cold boot event;
a reboot event;
a reset event;
a power state change event; and
a link error event.
14 . The method of claim 11 , further comprising:
establishing, by the first data storage device, control bus communication with a plurality of connected devices including the second device;
broadcasting, by the first data storage device and to the plurality of connected devices, a first peer message including the configuration data; and
storing, by each connected device of the plurality of connected devices, the configuration data.
15 . The method of claim 14 , further comprising:
storing, by the first data storage device and each connected device of the plurality of connected devices, a connected device registry, wherein:
each connected device registry includes connected device entries corresponding to each other device of the plurality of connected devices and the first data storage device; and
each connected device entry includes:
a connected device identifier; and
corresponding configuration data.
16 . The method of claim 11 , further comprising:
negotiating, by the first data storage device and using the configuration data, physical link training between the first data storage device and the host system according to the peripheral interface protocol to reestablish communication through the peripheral interface, wherein the configuration data comprises a set of coefficient values for physical link training.
17 . The method of claim 16 , wherein the set of coefficient values comprises coefficient presets for physical link filter values selected from a plurality of coefficient presets defined by the peripheral interface protocol.
18 . The method of claim 11 , wherein:
the first data storage device is one data storage device of a plurality of data storage devices configured for:
peer communication though the control bus; and
storage communication with the host system through the peripheral interface bus; and
the second device is a second data storage device of the plurality of data storage devices.
19 . The method of claim 11 , further comprising:
receiving, by the host system and through the control bus, the configuration data from the first data storage device during a first operating period;
storing, by the host system and in a memory of the host system, the configuration data during the first operating period; and
sending, by the host system and through the control bus, the configuration data to the first data storage device prior to reestablishing communication through the peripheral interface during a second operating period.
20 . A storage system comprising a plurality of data storage devices, wherein each data storage device comprises:
at least one processor;
at least one memory;
a storage interface configured to connect to a host system through a peripheral interface bus using a peripheral interface protocol to establish storage communication for that data storage device;
a control bus interface configured to connect to a control bus for control bus communication, wherein, during data storage device initialization, that data storage device establishes control bus communication prior to establishing storage communication with the host system;
a storage medium configured to store host data for that data storage device;
means, stored in the at least one memory for execution by the at least one processor, for receiving, responsive to a loss of connection event for the storage interface of that data storage device, through the control bus interface and from another data storage device of the plurality of data storage devices, configuration data for the peripheral interface protocol; and
means, stored in the at least one memory for execution by the at least one processor, for reestablishing, using the configuration data received from another data storage device of the plurality of data storage devices, storage communication through the storage interface to the host system.