Peripheral device, program and methods for responding to a warm reboot condition
A computing system peripheral device compatible with the peripheral component interconnect express (PCI-E) protocol responds to a DL_DOWN command primitive by configuring a general-purpose input/output (GPIO) port into a known state without invoking a GPIO module reset. In addition, select resources are excluded from resources on the peripheral device that are issued a reset command. The select resources can include a GPIO module, a memory element and a PCI-E SERDES module. After the remaining reset resources have completed their individual initialization processes, the central processor core on the peripheral device is reset. The described response to the DL_DOWN command primitive avoids cache data loss, masks signal transitions on I/O ports and timing problems that prevent some peripheral devices from being recognized in a computer's basic input/output system (BIOS).
1. A method for responding to a warm reboot condition in a peripheral device that responds to soft resets with a PCI-E DL_DOWN command primitive, the method comprising:
identifying a DL_DOWN command primitive in a PCI-E compatible device having a plurality of cores;
directing an input/output (I/O) port into a known state;
selectively directing a subset of the plurality of cores of the PCI-E compatible device to reset;
waiting for an indication of synchronization from the subset of the plurality of cores;
directing the subset of the plurality of cores into a non-reset condition;
waiting for an indication of synchronization from the subset of the plurality of cores; and
invoking a central processor unit reset.
2. The method of claim 1 , wherein the step of identifying a DL_DOWN command primitive in a PCI-E controller is performed in a redundant array of independent disks (RAID) controller.
3. The method of claim 1 , wherein the step of directing an I/O port into a known state comprises directing a general purpose I/O port into a default state without invoking a general purpose I/O module reset.
4. The method of claim 1 , wherein the step of selectively directing a subset of the plurality of cores of the PCI-E compatible devices to reset excludes a general purpose I/O module, a serializer/deserializer (SERDES) module, and a memory device.
5. The method of claim 1 , further comprising:
selectively directing a subset of the input/output resources of the PCI-E compatible device to reset.
6. The method of claim 5 , wherein the step of selectively directing a subset of the input/output resources of the PCI-E compatible device to reset excludes one or more of a hardware pin dedicated to a corresponding event trigger and an addressable 1-wire device.
7. The method of claim 1 , wherein the step of identifying a DL_DOWN command primitive in a PCI-E compatible device having a plurality of cores comprises a PCI-E compatible device with one or more of a serial attached small computer system interface (SAS) core, a direct-memory access (DMA) core, a static random-access memory (SRAM) core, a SAS SERDES core and a PCI-E SERDES core.
8. A computing system peripheral device compatible with the peripheral component interconnect express protocol, comprising:
a peripheral component interconnect express (PCI-E) core instantiated as an application specific integrated circuit on the peripheral device;
a central processor core coupled to the PCI-E core by way of a local bus, the local bus further coupling a general purpose input/output (GPIO) module, a memory element, and a PCI-E serializer/deserializer (SERDES) module to the PCI-E core and the central processor core; and
a non-volatile memory element coupled to the local bus, the non-volatile memory element configured to store a set of executable instructions responsive to a DL_DOWN interrupt primitive that when executed on the peripheral device direct a GPIO port into a known state and selectively direct a subset of available resources coupled to the local bus to reset before invoking a reset of the central processor core.
9. The computing system peripheral device of claim 8 , wherein the set of executable instructions in the non-volatile memory element direct the PCI-E core to wait for an indication that reset resources are synchronized before directing the reset resources to a non-reset state.
10. The computing system peripheral device of claim 9 , wherein the set of executable instructions in the non-volatile memory element direct the PCI-E core to wait for an indication that resources directed to the non-reset state are synchronized before invoking the reset of the central processor unit.
11. The computing system peripheral device of claim 10 , wherein the PCI-E core directs the GPIO port to a default state.
12. The computing system peripheral device of claim 8 , wherein the set of executable instructions in the non-volatile memory element direct the PCI-E core to reset all resources with the exception of the GPIO module, the PCI-E SERDES module and the memory element.
13. The computing system peripheral device of claim 8 , wherein the PCI-E core directs the selective reset of one or more I/O devices coupled to the local bus by way of an on-chip peripheral bus.
14. The computing system peripheral device of claim 13 , wherein the one or more I/O devices selected from the group consisting of a universal asynchronous receiver-transmitter (UART), a timer, an intelligent interface controller (I 2 C), and an extended industry standard bus controller.
15. A program including a set of executable instructions embodied on a computer readable storage medium, comprising:
logic configured to identify a DL_DOWN command primitive in a PCI-E compatible core;
logic configured to direct an input/output (I/O) port into a known state in response to the logic configured to identify the DL_DOWN command primitive;
logic configured to selectively direct a subset of the available resources of a PCI-E compatible device to reset;
logic configured to wait for an indication of synchronization from the subset of the available resources; and
logic configured to invoke a central processor unit reset responsive to the indication of synchronization.
16. The program of claim 15 , wherein the logic configured to identify a DL_DOWN command primitive in a PCI-E controller is executed in a redundant array of independent disks (RAID) controller.
17. The program of claim 15 , wherein the logic configured to direct an I/O port into a known state comprises logic configured to direct a general purpose I/O port into a default state without invoking a general purpose I/O module reset.
18. The program of claim 15 , wherein the logic configured to selectively direct a subset of the available resources of the PCI-E compatible device to reset excludes sending a reset to a general purpose I/O module, a serializer/deserializer (SERDES) module, and a memory device.
19. The program of claim 15 , further comprising:
logic configured to selectively direct a subset of the input/output resources of the PCI-E compatible device to reset.
20. The program of claim 19 , wherein the logic configured to selectively direct a subset of the input/output resources of the PCI-E compatible device to reset excludes one or more of a hardware pin dedicated to a corresponding event trigger and an addressable 1-wire device.