AMD manual AMD Geode CS5535 Companion Device Initialization, Chipset ID, Set ID Select Idsel

32430C Initialization

4.2AMD Geode™ CS5535 Companion Device Initialization

The Geode™ CS5535 is a complete companion device to the GX processor. The Geode CS5535 incorporates the GeodeLink technology developed in the GX processor to make a transparent GeodeLink through the PCI to the CS5535 device. The CS5535 companion device contains many of the components normally found on the SuperI/O chip. GeodeROM and VSA2 technology initialize these components, including the hard disk controller, USB controllers, GPIOs, RTC, SMBus, Local bus, and other legacy components. This chapter contains descriptions as well as some pseudo code for GX processor-specific code sequences in GeodeROM. The GX processor and CS5535 device do not implement com- plete PCI bus controllers, so GeodeLink modules that must be identified and configured by an operating system have their PCI configuration spaces virtualized by VSA.

4.2.1Chipset ID

Hardware PCI Header ID = 002A100Bh

Virtual PCI Header ID = 002B100bh

4.2.2Set ID Select (IDSEL)

The CS5535 companion device number is changeable by a 32-bit, write once register located in I/O space 0. By default, the CS5535 is located at device 15 (IDSEL = AD25). To insure that it is not accidentally moved, it must be programmed very early in post. The External MSR Access Configuration Register (GX GLPCI MSR Address 50000201Eh) must match the device number to route MSR transactions across the PCI bus.

Example:

; set IDSEL

mov eax, 02000000h

;mov eax, 04000000h out 0000h, eax

;set ExtMSR

mov eax, 0F0F0F0Fh mov edx, 000F0F0Fh

;mov eax, 14141414h

;mov edx, 00141414h mov ecx, extMSR

WRMSR

;IDSEL = AD25, device #15

;IDSEL = AD30, device #20

;device #15

;device #15

;device #20

;device #20

4.2.3GLIU Initialization

The CS5535 companion device contains one GLIU that connects up to six peripheral modules. The GLIU routes memory and I/O for the attached modules. Descriptors controlling memory and I/O for the attached modules are initialized by VSA technology. GeodeLink modules can be scanned for their identification. Non-legacy GeodeLink modules that must be visi- ble on the PCI bus will have PCI headers virtualized by VSA technology. The GLIU is configured with MSRs like all GX pro- cessor and CS5535 device modules.

VSA technology is also responsible for the Geode CS5535 descriptor allocation.

4.2.4Diverse Device Initialization

The Diverse Device (DD) is a collection of new and legacy devices that are located in I/O space and connected by the Local bus. It is also the subtractive decode port of the CS5535. Any memory or I/O not claimed by the DD is passed on to the Low Pin Count (LPC) bus. The CS5535 has provided complete flexibility to put non-legacy Local bus devices at any I/O location by implementing Local BARs (LBARs). The following subsections show recommended locations in I/O space to set the LBARs. Devices that may be used before VSA is initialized will be set by GeodeROM.

20 AMD Geode™ GX Processor/CS5535 Companion Device GeodeROM Porting Guide