Patents by Inventor Ramprasad Raghavan
Ramprasad Raghavan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20230131119Abstract: Detecting voltage-based attacks on an integrated circuit (IC) is difficult in the presence of clock jitter. Propagating signals can exhibit a total delay that is due to a delay component resulting from a voltage-based attack and a delay characteristic resulting from clock fluctuation. Voltage-variation detection circuitry includes first and second voltage-dependent circuits and a voltage analysis circuit. The voltage-dependent circuits produce first and second signals that are indicative of a voltage level responsive to a clock signal and based on different first and second voltage sensitivities. The voltage analysis circuit generates a voltage alert signal based on the first and second signals. A combined signal neutralizes the delay characteristic in the first and second signals, but the delay component due to the voltage variation can be at least partially maintained. Thus, a voltage-based attack is detectable in the presence of clock fluctuation by using two voltage-dependent circuits.Type: ApplicationFiled: October 31, 2022Publication date: April 27, 2023Applicant: Google LLCInventors: Emre Tuncer, Huachang Xu, Ramprasad Raghavan, Fanny Gur, Manish Harnur
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Patent number: 11486911Abstract: Detecting voltage-based attacks on an integrated circuit (IC) is difficult in the presence of clock jitter. Propagating signals can exhibit a total delay that is due to a delay component resulting from a voltage-based attack and a delay characteristic resulting from clock fluctuation. Voltage-variation detection circuitry includes first and second voltage-dependent circuits and a voltage analysis circuit. The voltage-dependent circuits produce first and second signals that are indicative of a voltage level responsive to a clock signal and based on different first and second voltage sensitivities. The voltage analysis circuit generates a voltage alert signal based on the first and second signals. A combined signal neutralizes the delay characteristic in the first and second signals, but the delay component due to the voltage variation can be at least partially maintained. Thus, a voltage-based attack is detectable in the presence of clock fluctuation by using two voltage-dependent circuits.Type: GrantFiled: July 22, 2020Date of Patent: November 1, 2022Assignee: Google LLCInventors: Emre Tuncer, Huachang Xu, Ramprasad Raghavan, Fanny Gur, Manish Harnur
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Publication number: 20210148957Abstract: Detecting voltage-based attacks on an integrated circuit (IC) is difficult in the presence of clock jitter. Propagating signals can exhibit a total delay that is due to a delay component resulting from a voltage-based attack and a delay characteristic resulting from clock fluctuation. Voltage-variation detection circuitry includes first and second voltage-dependent circuits and a voltage analysis circuit. The voltage-dependent circuits produce first and second signals that are indicative of a voltage level responsive to a clock signal and based on different first and second voltage sensitivities. The voltage analysis circuit generates a voltage alert signal based on the first and second signals. A combined signal neutralizes the delay characteristic in the first and second signals, but the delay component due to the voltage variation can be at least partially maintained. Thus, a voltage-based attack is detectable in the presence of clock fluctuation by using two voltage-dependent circuits.Type: ApplicationFiled: July 22, 2020Publication date: May 20, 2021Applicant: Google LLCInventors: Emre Tuncer, Huachang Xu, Ramprasad Raghavan, Fanny Gur, Manish Harnur
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Patent number: 9842074Abstract: Embodiments herein provide for tag allocation in a PCIe application layer. In one embodiment, an apparatus operable to interface with a plurality of virtual functions and a plurality of physical functions to process data via the PCIe protocol. The apparatus includes a packet builder communicatively coupled to each of the virtual functions and the physical functions and operable to build packets for non-posted commands from the virtual and physical functions. The apparatus also includes a tag allocator operable to allocate tags from a first set of tags to the packets of non-posted commands from any of the virtual and physical functions employing extended tags when the tags of the first set are available, and to reserve a second different set of tags for remaining virtual and physical functions not employing extended tags until the first set of tags are all allocated.Type: GrantFiled: January 30, 2015Date of Patent: December 12, 2017Assignee: AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE. LTD.Inventor: Ramprasad Raghavan
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Patent number: 9792245Abstract: Embodiments herein provide for efficient memory mapping in a PCIe device when a host changes memory allocations in the device. One PCIe device comprises a plurality of Base Address Registers (BARs) defined by the host. The device also includes a processor with an address space. The processor maps addresses of the address space to the BARs for routing PCIe packets from the host. The processor can determine that the host is reconfiguring the BARs, and, based on the determination, mark packets existing in the computer memory as old, change the BARs in the computer memory as directed by the host, mark packets received after the BAR change as new, process the old packets from the computer memory based on their addresses of the address space until a new packet is reached, and to remap the BARs to the addresses of the address space after the new packet is reached.Type: GrantFiled: December 9, 2014Date of Patent: October 17, 2017Assignee: AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE. LTD.Inventors: Ramprasad Raghavan, Eugene Saghi
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Patent number: 9424224Abstract: Systems and methods presented herein provide for tunneling PCIe data through a SAS domain. a data system includes a SAS expander, a PCIe target device coupled to the expander, and a SAS controller communicatively coupled to a host system and the expander. The controller is operable to open a connection with the expander via the SAS protocol, and to transport packet data between the target device and the host system through the connection via the PCIe protocol. For example, the controller and the expander may be operable to buffer packets of data in the connection. The controller may issue a number of the data packets to be transferred in the connection. Then, the issued number of data packets are transported between the target device and the host system through the connection via the PCIe protocol.Type: GrantFiled: June 27, 2013Date of Patent: August 23, 2016Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.Inventors: William W. Voorhees, George O. Penokie, William K. Petty, Ramprasad Raghavan, Eugene Saghi
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Publication number: 20160224487Abstract: Embodiments herein provide for tag allocation in a PCIe application layer. In one embodiment, an apparatus operable to interface with a plurality of virtual functions and a plurality of physical functions to process data via the PCIe protocol. The apparatus includes a packet builder communicatively coupled to each of the virtual functions and the physical functions and operable to build packets for non-posted commands from the virtual and physical functions. The apparatus also includes a tag allocator operable to allocate tags from a first set of tags to the packets of non-posted commands from any of the virtual and physical functions employing extended tags when the tags of the first set are available, and to reserve a second different set of tags for remaining virtual and physical functions not employing extended tags until the first set of tags are all allocated.Type: ApplicationFiled: January 30, 2015Publication date: August 4, 2016Inventor: Ramprasad Raghavan
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Publication number: 20160162436Abstract: Embodiments herein provide for efficient memory mapping in a PCIe device when a host changes memory allocations in the device. One PCIe device comprises a plurality of Base Address Registers (BARs) defined by the host. The device also includes a processor with an address space. The processor maps addresses of the address space to the BARs for routing PCIe packets from the host. The processor can determine that the host is reconfiguring the BARs, and, based on the determination, mark packets existing in the computer memory as old, change the BARs in the computer memory as directed by the host, mark packets received after the BAR change as new, process the old packets from the computer memory based on their addresses of the address space until a new packet is reached, and to remap the BARs to the addresses of the address space after the new packet is reached.Type: ApplicationFiled: December 9, 2014Publication date: June 9, 2016Inventors: Ramprasad Raghavan, Eugene Saghi
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Patent number: 9032143Abstract: Methods and structure are provided for representing ports of a Serial Attached SCSI (SAS) expander circuit within routing memory. The SAS expander includes a plurality of PHYs and a routing memory. The routing memory includes entries that each indicate a set of PHYs available for initiating a connection with a SAS address, and also includes an entry that represents a SAS port with a start tag indicating a first PHY of the port and a length tag indicating a number of PHYs in the port. The SAS expander also includes a Content Addressable Memory (CAM) including entries that each associate a SAS address with an entry in the routing memory. Further, the SAS expander includes a controller that receives a request for a SAS address, uses the CAM to determine a corresponding routing memory entry for the requested SAS address, and selects the port indicated by the corresponding routing memory entry.Type: GrantFiled: September 4, 2012Date of Patent: May 12, 2015Assignee: LSI CorporationInventor: Ramprasad Raghavan
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Patent number: 9026727Abstract: Methods and structure are provided for representing ports of a Serial Attached SCSI (SAS) expander circuit within routing memory. The SAS expander includes a plurality of PHYs and a routing memory. The routing memory includes entries that each indicate a set of PHYs available for initiating a connection with a SAS address, and also includes an entry that represents a SAS port with a start tag indicating a first PHY of the port and a length tag indicating a number of PHYs in the port. The SAS expander also includes a Content Addressable Memory (CAM) including entries that each associate a SAS address with an entry in the routing memory. Further, the SAS expander includes a controller that receives a request for a SAS address, uses the CAM to determine a corresponding routing memory entry for the requested SAS address, and selects the port indicated by the corresponding routing memory entry.Type: GrantFiled: September 4, 2012Date of Patent: May 5, 2015Assignee: Avago Technologies General IP (Singapore) Pte LtdInventor: Ramprasad Raghavan
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Publication number: 20140372637Abstract: Systems and methods presented herein provide for tunneling PCIe data through a SAS domain. a data system includes a SAS expander, a PCIe target device coupled to the expander, and a SAS controller communicatively coupled to a host system and the expander. The controller is operable to open a connection with the expander via the SAS protocol, and to transport packet data between the target device and the host system through the connection via the PCIe protocol. For example, the controller and the expander may be operable to buffer packets of data in the connection. The controller may issue a number of the data packets to be transferred in the connection. Then, the issued number of data packets are transported between the target device and the host system through the connection via the PCIe protocol.Type: ApplicationFiled: June 27, 2013Publication date: December 18, 2014Inventors: William W. Voorhees, George O. Penokie, William K. Petty, Ramprasad Raghavan, Eugene Saghi
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Patent number: 8850287Abstract: Methods and apparatus for enabling FCS and zoning operations in an enhanced SAS expander. Features and aspects hereof provide for enhanced logic within a SAS expander to detect receipt of an SAF in a zoning capable SAS expander and to modify the SAF to correct the zone group identifier and associated CRC to enable switching among a plurality of established connection (as provided by FCS enhancement) while maintaining accurate zoning information.Type: GrantFiled: October 19, 2012Date of Patent: September 30, 2014Assignee: LSI CorporationInventors: Ramprasad Raghavan, Nitin Satishchandra Kabra, Gurvinder Pal Singh
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Publication number: 20140115418Abstract: Methods and apparatus for enabling FCS and zoning operations in an enhanced SAS expander. Features and aspects hereof provide for enhanced logic within a SAS expander to detect receipt of an SAF in a zoning capable SAS expander and to modify the SAF to correct the zone group identifier and associated CRC to enable switching among a plurality of established connection (as provided by FCS enhancement) while maintaining accurate zoning information.Type: ApplicationFiled: October 19, 2012Publication date: April 24, 2014Applicant: LSI CORPORATIONInventors: Ramprasad Raghavan, Nitin Satishchandra Kabra, Gurvinder Pal Singh
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Publication number: 20140068177Abstract: Methods and structure are provided for representing ports of a Serial Attached SCSI (SAS) expander circuit within routing memory. The SAS expander includes a plurality of PHYs and a routing memory. The routing memory includes entries that each indicate a set of PHYs available for initiating a connection with a SAS address, and also includes an entry that represents a SAS port with a start tag indicating a first PHY of the port and a length tag indicating a number of PHYs in the port. The SAS expander also includes a Content Addressable Memory (CAM) including entries that each associate a SAS address with an entry in the routing memory. Further, the SAS expander includes a controller that receives a request for a SAS address, uses the CAM to determine a corresponding routing memory entry for the requested SAS address, and selects the port indicated by the corresponding routing memory entry.Type: ApplicationFiled: September 4, 2012Publication date: March 6, 2014Applicant: LSI CORPORATIONInventor: Ramprasad Raghavan
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Publication number: 20140068124Abstract: Methods and structure are provided for representing ports of a Serial Attached SCSI (SAS) expander circuit within routing memory. The SAS expander includes a plurality of PHYs and a routing memory. The routing memory includes entries that each indicate a set of PHYs available for initiating a connection with a SAS address, and also includes an entry that represents a SAS port with a start tag indicating a first PHY of the port and a length tag indicating a number of PHYs in the port. The SAS expander also includes a Content Addressable Memory (CAM) including entries that each associate a SAS address with an entry in the routing memory. Further, the SAS expander includes a controller that receives a request for a SAS address, uses the CAM to determine a corresponding routing memory entry for the requested SAS address, and selects the port indicated by the corresponding routing memory entry.Type: ApplicationFiled: September 4, 2012Publication date: March 6, 2014Applicant: LSI CORPORATIONInventor: Ramprasad Raghavan
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Patent number: 8626974Abstract: Methods and systems for reducing the signal path count between circuits within a SAS expander used for establishing SAS connections. The system comprises a SAS expander. The SAS expander comprises a plurality of link layer control circuits, each link layer control circuit adapted to communicatively couple with a SAS device. The SAS expander further comprises a connection manager communicatively coupled with the link layer control circuits for routing communications between the link layer control circuits. Each of the plurality of link layer control circuits is adapted to establish a SAS connection with another link layer control circuit through the connection manager by segmenting a plurality of interconnect signals into multiple data segments for sequential transmission to the connection manager, (e.g., without impacting the performance of the connection manager). The connection manager interprets the data segments to extract the plurality of interconnect signals to establish the SAS connection.Type: GrantFiled: January 19, 2012Date of Patent: January 7, 2014Assignee: LSI CorporationInventors: Ramprasad Raghavan, Alpana Bastimane
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Publication number: 20130191573Abstract: Methods and systems for reducing the signal path count between circuits within a SAS expander used for establishing SAS connections. The system comprises a SAS expander. The SAS expander comprises a plurality of link layer control circuits, each link layer control circuit adapted to communicatively couple with a SAS device. The SAS expander further comprises a connection manager communicatively coupled with the link layer control circuits for routing communications between the link layer control circuits. Each of the plurality of link layer control circuits is adapted to establish a SAS connection with another link layer control circuit through the connection manager by segmenting a plurality of interconnect signals into multiple data segments for sequential transmission to the connection manager, (e.g., without impacting the performance of the connection manager). The connection manager interprets the data segments to extract the plurality of interconnect signals to establish the SAS connection.Type: ApplicationFiled: January 19, 2012Publication date: July 25, 2013Applicant: LSI CORPORATIONInventors: Ramprasad Raghavan, Alpana Bastimane