Data processing device, coprocessor and methods performed thereby for interrupt handling

A method performed by a data processing device, wherein the data processing device comprises a central processing unit (CPU), and a coprocessor configured to perform predetermined tasks for a plurality of sessions, and to report, for at least one session satisfying a predetermined condition, at least one interrupt event to the CPU, the method comprising:

• operating, by the coprocessor, in a first mode where an interrupt signal is triggered immediately after there is an interrupt event needing to be reported to the CPU, and wherein there is an interrupt event needing to be reported to the CPU when:
• (a) an interrupt event occurs;
• or (b) an interrupt event occurs for a session and there has not been a same interrupt event reported previously to the CPU for the session;
• or (c) an interrupt event occurs for a session, and there has been a same interrupt event reported previously to the CPU for the session, and the CPU has finished handling of the session;
• maintaining, by the coprocessor, a bitmap table indicating, for each of the plurality of sessions, whether there is an interrupt event needing to be reported to the CPU;
• maintaining, by the coprocessor, row validity data indicating, for each of rows of the bitmap table, whether the row has at least one interrupt event needing to be reported to the CPU;
• and
• in response to the interrupt signal triggered by the coprocessor, reading, by the CPU, from the bitmap table, at least one row that has at least one interrupt event needing to be reported to the CPU, according to the row validity data.

A coprocessor for use in a data processing device, wherein the data processing device comprises a central processing unit (CPU), and the coprocessor configured to perform predetermined tasks for a plurality of sessions, and to report, for at least one session satisfying a predetermined condition, at least one interrupt event to the CPU;

• wherein the coprocessor is configured to operate in a first mode where an interrupt signal is triggered immediately after there is an interrupt event needing to be reported to the CPU, and wherein there is an interrupt event needing to be reported to the CPU when:
• (a) an interrupt event occurs;
• or (b) an interrupt event occurs for a session and there has not been a same interrupt event reported previously to the CPU for the session;
• or (c) an interrupt event occurs for a session, and there has been a same interrupt event reported previously to the CPU for the session, and the CPU has finished handling of the session;
• wherein the coprocessor is configured to maintain:
• a bitmap table indicating, for each of the plurality of sessions, whether there is an interrupt event needing to be reported to the CPU;
• and
• row validity data indicating, for each of rows of the bitmap table, whether the row has at least one interrupt event needing to be reported to the CPU.