freeze when reading a PCI bridge register
nicolas.lavocat at fr.thalesgroup.com
Wed Apr 22 22:28:36 EST 2009
Thank you for your advices! I try it as soon as possible! (the board is
not often available...)
Gabriel Paubert a écrit :
> On Wed, Apr 22, 2009 at 10:04:29AM +0200, Nicolas Lavocat wrote:
>> Hi everybody!
>> I' am trying to configure a PCI bridge on a private board, with a
>> powerpc . In a first time, I tried to get informations about PCI
>> devices, in order to be sure that my read and write methods work (
>> using 2 configuration registers, like on an x86 architecture.) . 2
>> configuration registers are used, for example we write an encoded
>> address (it is a request to a PCI device) in the first and the answer of
>> the PCI device can be read in the second register (it is a configuration
>> Firstly, I did it by JTAG: it works. Then, under uboot, it is ok.
> JTAG is probably a completely different hardware path, so it
> does not really count. uboot testing is ok.
>> For example, the code used under u-boot:
>> volatile u32* addr;
>> u32 vendor_device_ID;
>> puts("PCI1 reading PCI VENDOR and DEVICE ID\n");
>> addr= CFG_DATA_PCI1;
>> vendor_device_ID= *addr;
>> printf("PCI1: PCI1_VENDOR_DEVICE_ID= %08x \n" ,vendor_device_ID);
> 2 possibilities:
> - your I/O is not marked uncacheable (should be with ioremap)
> - the PPC is reordering and issuing the read before the write,
> you should use accessors. A simple test is inserting
> an asm volatile("eieio") before the read.
> About your other mails, please avoid HTML mail.
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