Patent Document

FIELD OF THE INVENTION 
     The present invention is generally concerned with peripheral computer equipment, and more specifically related to performing maintenance on a double-slot PCI device. 
     BACKGROUND 
     Computer systems may include a peripheral device interconnect system, such as a PCI (Peripheral Component Interconnect) or ISA (Industry Standard Architecture) interface. Such interconnect systems may facilitate the connectivity and configuration of peripheral devices in a computer system. For example, using a PCI interface, a computer system may be able to recognize when a peripheral device has been inserted, identify the location of the port at which it has been inserted, and determine the identity of the installed peripheral device. 
     Peripheral devices are typically single-slotted, meaning that they may be inserted into a single slot of an interconnect port. However, multiple-slotted devices are now being developed. Since the interconnect systems are generally designed to accommodate single-slot devices, it would be useful to provide a method and system for accommodating multiple-slotted devices. 
     SUMMARY OF THE INVENTION 
     In a first aspect of the invention, a method is provided for performing maintenance on a multiple-slot device having multiple adapters in a computer system including a peripheral interface having a plurality of device connection slots. The method includes the steps of determining a selected slot on the peripheral interface is associated with an adapter of a multiple-slot device, identifying a further slot associated with the multiple-slot device based on the selected slot, and providing power to or removing power from the selected slot and the identified further slot. 
     In a second aspect of the invention, a computer system is provided that is adapted to employ multiple-slot devices. The computer system includes a peripheral interface including a planar having a plurality of device connection slots and a processor coupled to the peripheral interface adapted to execute an operating system to obtain data from and allocate power to the device connection slots of the peripheral interface. The processor is further adapted to determine from data obtained from the peripheral device whether a slot of the peripheral interface is occupied by an adapter of a multiple-slot device, to identify a further slot occupied by a further adapter of the multiple-slot device and to allocate power to occupied slots of the multiple-slot device. 
     Other features and aspects of the present invention will become more fully apparent from the following detailed description, the appended claims and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of a computer system in accordance with an embodiment of the present invention. 
         FIG. 2  is a back view of an embodiment of an enclosure, which houses a horizontally oriented I/O planar. 
         FIG. 3A  is a back view of an embodiment of an enclosure, which houses a vertically oriented I/O planar having slots extending rightwards from the I/O planar. 
         FIG. 3B  is a back view of an embodiment of an enclosure, which houses a vertically oriented I/O planar having slots extending leftwards from the I/O planar. 
         FIG. 4  is an embodiment of a PCI config space. 
         FIG. 5A  is an embodiment of a method for removing a double-slot device during system operation. 
         FIG. 5B  is an embodiment of a method for adding a double-slot device during system operation. 
         FIG. 6  is a back view of an embodiment of an enclosure, which houses a horizontally oriented I/O planar having slots extending upwards from the I/O planar. 
     
    
    
     DETAILED DESCRIPTION 
     PCI devices, i.e., peripheral devices that may be used in a PCI interconnect system (also known as PCI cards), conventionally include an adapter that fits into a single slot of a PCI motherboard or planar. New devices have been developed that include multiple standard PCI adapters coupled together, and that take up more than one slot on the planar. For example, devices which include two PCI adapters are known as ‘double-slot’ devices, as opposed to the conventional ‘single-slot’ devices. In a multiple-slot device, each of the component adapters may occupy adjacent PCI input slots. 
     Each slot in a PCI planar typically has a unique identification label. For example, in IBM system i devices, the slot label may provide a location code for a PCI device connection. In some embodiments, the slot label may be stored as non-volatile vital product data (VPD) in the planar. For example, in IBM system i, a series of PCI slots are numbered sequentially from left to right and top to bottom when viewed from the service position, (e.g., from the back of the enclosure which is typically accessed for maintenance purposes). 
     PCI devices, in turn, usually include locally-stored data often referred to as ‘standard PCI config data’. This data may include device ID, vendor ID, subsystem ID and subsystem vendor ID, which are collectively referred to as the PCI config ID. This information uniquely identifies a specific PCI single-slot device or adapter. 
     In the case of a double-slot PCI device having two adapters coupled together, each of the two adapters, or halves, may include a unique PCI config ID that allows an operating system (OS) to uniquely identify each individual adapter. For example, in a double-slot device, the PCI config IDs may identify a first adapter, which may be, for example, on the left side when viewed from the service position, versus a second adapter, which may be on the right side when viewed from the service position. 
     Concurrent maintenance of a PCI device refers to adding, removing or replacing the device in a PCI slot during full or partial system operation, (e.g., while the operating system is running). However, a particular slot into which a device is being inserted or from which it is being removed is usually powered off during the operation. In the case of single-slot devices, the PCI slot label of the selected slot is identified and used to power off the slot. 
     The present invention provides a method and system for enabling the OS to identify a device in question as a multiple-slot device, and then to identify all of the PCI slots associated (or to be associated) with the multiple-slot device, and their orientation with respect to one another. Those slots identified can then be powered off for maintenance operations. According to one or more embodiments of the present invention, the OS determines that a selected slot is associated with a portion of a multiple-slot adapter and then derives the location of the other portion(s) so that all the slots associated with each of the individual adapters in the multiple-slot device may be powered off when the user selects any portion of the device. 
     With reference to  FIG. 1 , in one or more embodiments, a computer system  100  may include a processor which may be a central processing unit (CPU)  101  of a computer that is adapted to execute an operating system (among other functions). The CPU  101  is coupled, via a system bus  102 , to system memory  104 . The CPU  101  is also coupled through the system bus  102  to one or more peripheral buses, such as a PCI bus  106 , and/or an ISA bus  108  via bus bridges  110  (between the system bus  102  and the PCI bus  106 ) and  112  (between the PCI bus  106  and the ISA bus  108 ). Peripheral devices, e.g.,  114 ,  116  may be coupled to the PCI and ISA buses  106 ,  108 , respectively. In operation, the CPU  101  may transmit information to and receive information from the peripheral devices  114 ,  116  during execution of the operating system. 
       FIG. 2  illustrates a back view of an embodiment of a computer enclosure  200 , which houses a horizontally oriented PCI bus or input/output planar (‘I/O planar’)  202  having slots C 1 -C 8 . The enclosure  200  has an enclosure label U5296.001.4444444, which contains data that may indicate that the computer enclosure  200  is a “drawer-style” enclosure housing a horizontally oriented I/O planar  202 . The relative numbering of the labels of slots C 1 -C 8  may be a function of the orientation of the enclosure and the direction in which the slots open out. This orientational and directional information is reflected in an identification label, such as custom card identification number ‘CCIN’ of the I/O planar  202 , which may be stored in non-volatile VPD on the I/O planar  202 . 
     The slots C 1 -C 8  of I/O planar  202  are adapted to receive PCI devices. In the horizontal orientation of the I/O planar  202 , the slots C 1 -C 8  are oriented vertically, with the result that PCI devices coupled to the slots are oriented vertically as well. The slot labels C 1 -C 8  for the slots on the I/O planar  202  may be stored in non-volatile VPD residing on the I/O planar  202  and may be used as an index for accessing other attributes and characteristics of the slots contained in the VPD. In the exemplary embodiment shown in  FIG. 2 , slots C 1  and C 3  are occupied by single-slot PCI devices  204 ,  206 , respectively, and slots C 6  and C 7  are occupied by a double-slot PCI device  208  having adapters  209   a ,  209   b . Sequential slots may be numbered left-to-right and top-to-bottom according to rules determined by the system architecture. In the case of a horizontally oriented I/O planar  202 , the slot of adapter  209   a  of a double-slot device  208  may be labeled C(x−1), while the slot of adapter  209   b  may be labeled C(x). For example, the slot of the left half of double-slot device  208  may be labeled C 6 , and the slot of the right half of double-slot device  208  may be labeled C 7 . 
       FIG. 3   a  illustrates a back view of an exemplary embodiment of another computer enclosure  300 , which houses a vertically oriented I/O planar  302  having slots C 1 -C 8  extending rightwards from the I/O planar  302  when viewed from the service position. The example label of the enclosure, U5296.001.5555555, includes information which indicates that the enclosure  300  is a “tower-style” enclosure housing a vertically oriented I/O planar  302  situated on a left side of the enclosure interior when viewed from the service position. In this case, the planar slots C 1 -C 8  and PCI devices coupled to the slots C 1 -C 8  are oriented horizontally. In the depicted example, slots C 1  and C 3  are occupied by single-slot PCI devices  304 ,  306 , respectively, and slots C 6  and C 7  are occupied by a double-slot PCI device  308  having adapters  309   a  and  309   b . The slot label of the left half adapter  309   a  of double-slot device  308  is C 6 , and the slot label of the right half adapter  309   b  of double-slot device  308  is C 7 . 
       FIG. 3   b  illustrates a back view of another example embodiment of a computer enclosure  310 , which houses a vertically oriented I/O planar  312  having, in this example, slots C 1 -C 8  extending leftwards from the I/O planar  302  when viewed from the service position. The example label of the enclosure, U5296.001.6666666, includes information which indicates that the enclosure  310  is a “tower-style” enclosure housing a vertically oriented I/O planar  312  situated on the right side of the enclosure interior when viewed from the service position. The planar slots C 1 -C 8  and PCI devices coupled to the slots C 1 -C 8  are oriented horizontally. In this instance, slots C 1  and C 3  are occupied by single-slot PCI adapters  314 ,  316 , respectively, and slots C 6  and C 7  are occupied by a double-slot PCI adapter  318 . In the exemplary left-to-right and top-to-bottom numbering of PCI slot labels (e.g., as the enclosure  310  may be viewed when turned so that the I/O planar  312  is horizontally oriented) the slot label of the left half of a double-slot device may be labeled as C(x+1) with the slot label of the right half labeled as C(x). Thus, in the depicted example, the slot label of the left half adapter  319   a  of double-slot device  318  is C 7 , and the slot label of the right half adapter  319   b  of double-slot device  318  is C 6 , in contrast to the labeling depicted in  FIGS. 2 and 3   a.    
     As discussed above, the slot labels for the slots on an I/O planar may be stored in non-volatile VPD residing on the I/O planar and may be used as an index to the VPD associated with each slot to access additional information. Similarly, each adapter that is coupled to a slot on an I/O planar in an enclosure and conforms to the PCI standard may include information stored in non-volatile adapter storage. This storage may be referred to as ‘standard PCI config space’, and the information may be referred to as ‘standard PCI config data’. 
       FIG. 4  illustrates an embodiment of a PCI config space  400 . Included in this PCI config space  400  are a device ID, a vendor ID, a subsystem ID, and a subsystem vendor ID, which may be collectively referred to as the ‘PCI config ID’  402 . As is apparent from the figure, the device and subsystem IDs may be contained in a single fields  404  and  405 , respectively, which may have a length of 16 bits, and the vendor and subsystem vendor IDs may be contained in other fields  406  and  407 , respectively, which may have a length of 16 bits. Other field sizes may be used. The PCI config ID  402  is intended to uniquely identify a particular adapter. In addition, in the case of a double-slot device, each of the two halves or adapters of a double-slot device may have a unique PCI config ID  402  that may allow the OS to uniquely identify that adapter as the left half or the right half of a double-slot device. 
     An exemplary method for performing concurrent maintenance on a multiple-slot device, i.e. adding, removing, or replacing the multiple-slot adapter during full or partial system operation, is discussed below with reference to  FIGS. 5   a  and  5   b.    
       FIG. 5   a  illustrates an embodiment of a method for removing a double-slot device during system operation. The method begins at step  500 . In step  502 , one of the slots in which a double-slot PCI adapter to be removed resides is selected. The selection may be performed by maintenance personnel or any other operator of the computer system. In step  504 , the OS accesses the PCI config ID of the adaptor in the selected slot, and determines, in step  506 , if the selected slot contains one half, i.e., the right half or the left half, of a double-slot device. If the selected slot is not one half of a double-slot device, then the method cycles back to step  502 , and another slot may be selected. If the selected slot is one half of a double-slot device, then the method goes on to step  508 . 
     In some systems, such as for example, IBM system i implementations, each adapter of a double-slot PCI device includes a device ID within the PCI config space that is numbered within a range of values that enables it to be identified as a left half versus a right half (or vice versa) of the double-slot device. For example, the device ID of the left half of a double-slot device may have values within a first specified range and the device ID of the right half of a double-slot device may have values within a second specified range. An advantage of this numbering is that the OS merely checks for a value within the range of values for a left versus right adapter whenever a similar adapter is introduced into the slot. 
     Referring again to step  508 , the OS determines, with knowledge of the selected slot and the PCI config ID, whether the selected slot is occupied by the right or left half of the double-slot device, when the double-slot device is viewed from the service position. Then, in step  510 , the OS determines the slot label of the other half of the double-slot device, using the CCIN label of the I/O planar and the numbering rules discussed above with regard to  FIGS. 2 ,  3   a , and  3   b . In particular, the OS accesses the CCIN label of the I/O planar to determine the label of the other half of the double-slot device, i.e., whether the slot label of the other half of the double-slot device is one higher or one lower than the selected slot. In step  512 , the OS subsequently powers off the two slots occupied by the double-slot device, and in step  514 , the double-slot device may be removed from the I/O planar. Step  516  marks the end of the exemplary method for removing a double-slot device during system operation. 
       FIG. 5   b  illustrates an exemplary embodiment of a method for adding a double-slot device during system operation. The method begins with step  518 . In step  520 , a double-slot device is inserted into adjacent vacant slots of the I/O planar. The insertion may be performed by maintenance personnel or any other operator of the computer system. In step  522 , one of the slots in which the double-slot device has been inserted is selected. The OS then powers on the selected slot in step  524 . In step  526 , the OS then accesses the PCI config ID of the adaptor inserted in the selected slot to determine, in step  528 , whether or not the selected slot contains one half of a double-slot device. If it does not, the method cycles back to step  522 , and another slot occupied by the double-slot device may be selected. If the selected slot does contain one half of a double-slot device, the method proceeds to step  530 , where the OS accesses the PCI config ID to determine whether the adapter in the selected slot is the left half or the right half of the double-slot device, when the double-slot device is viewed from the service position. In step  532 , the OS determines the slot label of the other half of the double-slot device in a manner similar to that discussed in step  510  of  FIG. 5   a . Finally, in step  534 , the OS powers on the slot containing the other half of the double-slot device. Step  536  marks the end of the exemplary method for adding a double-slot device during system operation. 
     Although these methods have been discussed with reference to a double-slot device, it should be pointed out that they may be applied to multiple-slot devices having any number of adapters (e.g., 2, 3, 4, 6, 8 etc.) by repeating the iterative procedures outlined in the methods above an appropriate number of times. For example,  FIG. 6  illustrates an I/O planar  602  having a triple-slot device. As shown, a computer enclosure  600  houses a horizontally oriented I/O planar  602  having slots C 1 -C 8  extending upwards from the I/O planar  602  when viewed from the service position. As can be discerned, slots C 5 , C 6  and C 7  are occupied by a triple-slot device  604  having adapters  605   a  (left),  605   b  (center) and  605   c  (right). The slot labels of adapters  605   a ,  605   b  and  605   c  are C 5 , C 6  and C 7 , respectively. 
     In the case of performing concurrent maintenance on such a multiple-slot device  604 , i.e., removing it from or adding it to the PCI planar  602  during system operation, the methods for doing so are analogous to those described in FIGS.  5   a  and  5   b . For example, the three adapters  605   a ,  605   b  and  605   c  may have information in their PCI config IDs identifying them as the left, middle and right adapters, respectively, of the multiple-slot device  604  (instead of ranges for just the right and left adapters of a double-slot device). Similarly, if, for example, the PCI device were a quadruple-slot device, the PCI config IDs of its adapters would identify them as falling in ranges reserved for the left, center-left, center-right and right adapters, etc. 
     Additionally, in the case of the multiple-slot device  604  (e.g., a three-adapter device), the OS may use the CCIN of the I/O planar  602  to determine whether the slot labels of the two slots not selected in the methods of  FIGS. 5   a  and  5   b  are both higher or both lower than the label of the selected slot, or whether the slot label of one unselected slot is one higher and that of the other unselected slot is one lower than the label of the selected slot. 
     The foregoing description discloses only exemplary embodiments of the invention; modifications of the above disclosed methods and apparatus which fall within the scope of the invention will be readily apparent to those of ordinary skill in the art. For example, in some embodiments, a new VPD term may be added to the standard PCI config space VPD that may directly indicate that an adapter is part of a multiple-slot adapter. This improvement may make it easier for the OS to support multiple-slot devices (e.g., new models) having PCI config IDs that do not fall within the standard, pre-set ranges reserved for multiple-slot devices. In other embodiments, a new VPD term or terms may be added to the I/O planar VPD that may specify the labels of slots adjacent to a slot in question (i.e., one or more consecutive slots to the right and left of the slot in question). This improvement may make it easier for the OS to support I/O planars (e.g., new planar models) having slot labels/numbers that do not follow standard slot labeling rules. 
     Accordingly, while the present invention has been disclosed in connection with specific embodiments thereof, it should be understood that other embodiments may fall within the spirit and scope of the invention, as defined by the following claims.

Technology Category: 3