JP7643116B2 - Image processing controller, image forming apparatus and control method - Google Patents

Description

The present invention relates to an image processing controller, an image forming device, and a control method.

Conventionally, controllers that control image forming devices are connected to devices such as scanner engines and plotter engines via a PCI bus to enable high-speed communication.

PCI connections are subject to physical constraints on the PCI address space due to the controller architecture, and previously it was only possible to select devices to be connected in configurations that fit within the PCI address space available to the controller.

Patent Document 1 discloses a technology that divides the subordinates of two or more parallel PCI-PCI bridges into a normal system and a redundant system, realizing a redundant configuration of devices while suppressing resource consumption.

When trying to solve the problem that devices can only be selected to be connected in a configuration that fits within the PCI address space that the controller can use, the technology disclosed in Patent Document 1 has the problem that devices cannot coexist because it is based on the assumption of redundant PCI devices.

The present invention has been made in consideration of the above, and aims to reduce the consumption of physical resources in the PCI address space when different PCI devices are used together.

In order to solve the above-mentioned problems and achieve the object, the present invention provides an image processing controller that performs image processing on a PCI device in accordance with instructions from a control unit, the image processing controller comprising: a system control unit that controls the entire image processing controller in accordance with instructions from the control unit; a PCI control unit that controls communication with the PCI device in response to a request from the system control unit when connected to the PCI device via PCI; a PCI address space that is a memory area reserved for communication with the PCI device; and a dummy space for provisionally setting addresses of BARs (Base Address Registers) that cannot be mapped into the PCI address space, wherein the system control unit reserves an address of the dummy space and sets it in a BAR of a configuration register, and when the system control unit initializes the PCI, the system control unit sets the address of the dummy space reserved in the BAR setting of the configuration register, and when the PCI control unit receives a request from the system control unit targeting an address of the dummy space, it exchanges addresses of the dummy space and the PCI address space to enable access to the target BAR.

The present invention has the advantage of being able to reduce the consumption of physical resources in the PCI address space when different PCI devices are used together.

FIG. 1 is a block diagram showing a configuration of an MFP according to an embodiment. FIG. 2 is a diagram showing a conventional PCI device specification. FIG. 3 is a diagram showing a conventional example in which the PCI address space is insufficient. FIG. 4 is a diagram showing the functional configuration of the controller ASIC. FIG. 5 is a sequence diagram showing an example of PCI address space swap control. FIG. 6 is a diagram illustrating an example of swap control of a PCI address space.

Embodiments of the image processing controller, image forming device, and control method are described in detail below with reference to the attached drawings.

In this embodiment, an example will be described in which a multifunction peripheral (MFP) is used as an image forming device. Note that a multifunction peripheral is a device that has at least two of the following functions: copy function, scanner function, fax function, and printer function.

Fig. 1 is a block diagram showing the configuration of an MFP 100 according to an embodiment. As shown in Fig. 1, the MFP 100 includes a controller ASIC (Application Specific Integrated Circuit) 101 which is an image processing controller, a chipset 102, a CPU (Central Processing Unit) 103 which is a control unit, memory 104, a HDD (Hard Disk Drive) 105, an engine 106 which is a PCI device such as a scanner or plotter, and an option 107 which is a PCI device.

The controller ASIC 101 is connected to the HDD 105. The controller ASIC 101 is also connected to an engine 106 such as a scanner or plotter via a PCI (Peripheral Component Interconnect) 108, and to an option 107, which is an external I/F such as IEEE1394, via a PCI 109.

The scanner engine 106 is a device that controls image reading. The plotter engine 106 is a device that controls image formation.

The controller ASIC 101 and the CPU 103 are connected via a chipset 102. The chipset 102 and the controller ASIC 101 are connected by a PCI 110. The chipset 102 is also connected to a memory 104.

Under the control of the CPU 103, the controller ASIC 101 processes and edits image data input from the engine 106, which is a scanner, and outputs the image data to the engine 106, which is a plotter.

Here, Figure 2 shows conventional PCI device specifications, and Figure 3 shows a conventional example of insufficient PCI address space. Conventionally, when connecting different devices to a controller via PCI, there are physical restrictions on the PCI address space due to the controller's architecture, and devices could only be selected to be connected in a configuration that fits within the PCI address space available to the controller. The example shown in Figures 2 and 3 shows a case where, when attempting to connect two devices (Device 1, Device 2) to a controller, there is a shortage of PCI address space of 97 MB for a PCI address space of 256 MB.

Therefore, in this embodiment, the controller ASIC 101 enables device connections that go beyond the physical constraints of the PCI address space. This is described in detail below.

First, the functional configuration of the controller ASIC 101 will be described. FIG. 4 is a diagram showing the functional configuration of the controller ASIC 101. As shown in FIG. 4, the controller ASIC 101 functions as a system control unit 1011, a PCI control unit 1012, a PCI address space 1013, and a dummy space for swap 1014, which is a dummy space.

PCI address space 1013 is a memory area reserved for communication with PCI devices connected via PCI.

The dummy swap space 1014 is a backup area provided in general-purpose memory such as DRAM to temporarily set the addresses of BARs (Base Address Registers) that cannot be mapped into the PCI address space 103 in order to resolve memory space shortages in the PCI address space 103 during PCI initialization (system startup).

The system control unit 1011 controls the entire controller ASIC 101 in accordance with instructions from the CPU 103 via the chipset 102. The system control unit 1011 reserves addresses in the dummy space 1014 for swapping, and sets them in the BAR (Base Address Registers) of the configuration register.

When the PCI control unit 1012 is connected to a PCI device via the PCI 109 or the like, it performs PCI control to control communication with the PCI device in response to a request from the system control unit 1011. When the PCI control unit 1012 receives a request from the system control unit 1011 targeting an address in the dummy space for swap 1014 during PCI initialization (system startup), it swaps (exchanges) the addresses in the dummy space for swap 1014 and the PCI address space 1013 to enable access to the target BAR.

Here, FIG. 5 is a sequence diagram showing an example of PCI address space swap control, and FIG. 6 is a diagram showing an example of swap control of PCI address space 1013. As shown in FIG. 5, the system control unit 1011 reserves the address of the dummy space 1014 for swap in the BAR (Base Address Registers) of the configuration register (step S1). When initializing the PCI (when starting the system), the system control unit 1011 sets the address of the dummy space 1014 for swap reserved in the BAR setting of the configuration register (step S2).

The area of the BAR to which an address in the dummy swap space 1014 is set cannot be accessed as is. Therefore, when the PCI control unit 1012 receives a request from the system control unit 1011 targeting an address in the dummy swap space 1014 (step S3), it swaps (exchanges) the addresses in the dummy swap space 1014 and the PCI address space 1013 to enable access to the target BAR (step S4).

By executing the above-mentioned process, as shown in FIG. 6, it becomes possible to connect devices beyond the physical constraints of the PCI address space 1013. In addition, since there is no need to block PCI devices when switching, as in the technology disclosed in Patent Document 1, free switching is possible without the constraint of redundant PCI devices.

In this way, this embodiment makes it possible to reduce the consumption of physical resources in the PCI address space when different PCI devices are used together.

In the above embodiment, the image forming device of the present invention is described as being applied to a multifunction device having at least two of the following functions: copy function, printer function, scanner function, and facsimile function. However, the image forming device can be applied to any image forming device, such as a copier, printer, scanner device, or facsimile device.

REFERENCE SIGNS LIST 100 Image forming apparatus 101 Image processing controller 103 Control unit 106, 107 PCI device 1011 System control unit 1012 PCI control unit 1013 PCI address space 1014 Dummy space

JP 2011-204077 A

Claims (4)

In an image processing controller that performs image processing for a PCI device in accordance with an instruction from a control unit,
a system control unit that controls the entire image processing controller in accordance with instructions from the control unit;
a PCI control unit that controls communication with the PCI device in response to a request from the system control unit when the PCI device is connected via a PCI;
a PCI address space which is a memory area reserved for communication with the PCI device;
a dummy space for provisionally setting addresses of BARs (Base Address Registers) that cannot be mapped into the PCI address space;
Equipped with
The system control unit reserves an address of the dummy space and sets the reserved address in a BAR of a configuration register;
The system control unit sets the address of the dummy space reserved in the BAR setting of a configuration register at the time of PCI initialization,
when the PCI control unit receives a request from the system control unit for an address in the dummy space, the PCI control unit exchanges addresses in the dummy space and the PCI address space to enable access to the target BAR.
13. An image processing controller comprising: the system control unit prepares a dummy space in a general-purpose memory for provisionally setting addresses of BARs that cannot be mapped to the PCI address space;
2. The image processing controller according to claim 1. A control unit;
A PCI device;
The image processing controller according to claim 1 or 2;
An image forming apparatus comprising: A control method for an image processing controller that performs image processing on a PCI device in accordance with an instruction from a control unit, comprising:
The image processing controller is
a system control unit that controls the entire image processing controller in accordance with instructions from the control unit;
a PCI control unit that controls communication with the PCI device in response to a request from the system control unit when the PCI device is connected via a PCI;
a PCI address space which is a memory area reserved for communication with the PCI device;
a dummy space for provisionally setting addresses of BARs (Base Address Registers) that cannot be mapped into the PCI address space;
Equipped with
the system control unit reserving an address of the dummy space and setting the reserved address in a BAR of a configuration register;
a step of the system control unit setting an address of the dummy space reserved in a BAR setting of a configuration register at the time of initialization of a PCI;
a step of, when the PCI control unit receives a request for an address in a dummy space for provisionally setting an address of a BAR (Base Address Register) that cannot be mapped to a PCI address space, which is a memory area reserved for communication with the PCI device, exchanging an address in the dummy space with an address in the PCI address space to enable access to the target BAR;
A control method comprising :

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