On Tue, Aug 05, 2008 at 04:23:10PM +0400, Michael Kolesov wrote: > Hello! > > I'm writing QNX6 Tundra Tsi148 VME manager. And currently I'm based on > Tsi148 linux driver. > I have some questions about pci-relative function calls. To start with, have you read Documentation/pci.txt ? > So. In Tundra spec there is requestment of : > "STAL (Start Address Lower): This field determines the start address of a particular memory > area on the PCI/X bus which is used to access VMEbus resources. The value of this field is > compared with A31-A16 of the PCI/X bus address" > Please see source code of this part in linux driver,with comments > bellow: > (full source can be found on http://www-zeuthen.desy.de/pitz/control_doc/MVME6100/Tsi148driver.tar) > //---------------------------------------------------------------------------- > // vmeSetOutBound > // Set attributes of an outbound window. > //---------------------------------------------------------------------------- > int > vmeSetOutBound( vmeOutWindowCfg_t *vmeOut) > { > int windowNbr = vmeOut->windowNbr; > unsigned int existingSize; > > if(vmepcimem == 0) > return(-ENOMEM); > if(vmeOut->windowSizeL == 0) > return(-EINVAL); > > // Allocate and map PCI memory space for this window. > existingSize = out_resource[windowNbr].end - out_resource[windowNbr].start; > if(existingSize != vmeOut->windowSizeL){ > if(existingSize != 0){ > iounmap((char *)out_image_va[windowNbr]); > release_resource(&out_resource[windowNbr]); > memset(&out_resource[windowNbr], 0, sizeof(struct resource)); > } > if(allocate_resource(vmepcimem, &out_resource[windowNbr], > vmeOut->windowSizeL, 0, 0xFFFFFFFF, 0x10000, 0,0)) { > printk("allocation failed for 0x%x-0x%x (0x%x)\n", out_resource[windowNbr].start, > out_resource[windowNbr].end, vmeOut->windowSizeL); > return(-ENOMEM); > } > > out_image_va[windowNbr] = > (int )ioremap(out_resource[windowNbr].start, vmeOut->windowSizeL); > if(out_image_va[windowNbr] == 0){ > release_resource(&out_resource[windowNbr]); > memset(&out_resource[windowNbr], 0, sizeof(struct resource)); > return(-ENOMEM); > } > } > > vmeOut->pciBusAddrL = out_resource[windowNbr].start > - pci_bus_mem_base_phys(vmechip_bus); > > switch(vmechip_devid) { > case PCI_DEVICE_ID_TUNDRA_CA91C042: > return(uniSetOutBound(vmeOut)); > break; > case PCI_DEVICE_ID_TUNDRA_TEMPE: > return(tempeSetOutBound(vmeOut)); > break; > } > return(-ENODEV); > } > > > > In linux code I see three main functions doing spec's requirements > > > 1. allocate_resource > > allocate_resource(vmepcimem, &out_resource[windowNbr], > vmeOut->windowSizeL, 0, 0xFFFFFFFF, 0x10000, 0,0) drivers should generally not need to directly call this. See pci.txt for the pci_resource interfaces. > vmepcimem - is 'struct resource' and before it was > assigned by pci_find_parent_resource(vme_pci_dev, &pcimemres), where > vme_pci_dev is Tundra Tsi148 pci_dev structure. > > windowSizeL - size of needed memory window > > out_resource is 'struct resource' too, for new mem area. > ----------- > Where out_resource's start and end fields will be? > My opinion, right after Tsi148 PCI address space region. > What allocate_resource realy do in linux? > Why we just can't do mmap-like function with pci-address, as example? "pci-address" might not be 1:1 with the "host bus" address that the CPU should be using. e.g. MMIO 0x10000 on the PCI bus might be accessed through 0x8 0010 0000 host physical address (assumes 64-bit arch). > ----------- > > 2. ioremap > > out_image_va[windowNbr] = > (int )ioremap(out_resource[windowNbr].start, vmeOut->windowSizeL); > > out_image_va - virtual address of previously allocated mem space, > throught which we can access new allocated space. > > I read, it used for making special kernel virtual space address, and > it maps high PCI addresses. > > 3. pci_bus_mem_base_phys > > vmeOut->pciBusAddrL = out_resource[windowNbr].start > - pci_bus_mem_base_phys(vmechip_bus); > > vmechip_bus == 0. > -------------- > So we can get start address of PCI range, right? Yes, but unless the device is doing Peer-to-Peer transfers on the PCI bus, the driver should be using the resource_start() values. > ------------- > > ////////////////////////// > > Please correct me, if I got wrong understanding of functions above. hth, grant > > With Best Regards, > Michael Kolesov > software developer > CBD BC, Saint-Petersburg, Russia > > > > > > > > > > > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
