From: "Michael Brown" <mcb30@ipxe.org>
To: devel@edk2.groups.io, grao.v80@gmail.com
Subject: Re: [edk2-devel] Read SPI BAR offset 0x10 throwing processor exception
Date: Fri, 28 Jan 2022 12:59:24 +0000 [thread overview]
Message-ID: <735241e7-8ada-0fb0-e035-0a88d0800403@ipxe.org> (raw)
In-Reply-To: <CAFz4ObH6Lz363izuGhhs5tfSJWZvBwuHvT_OXfyAG8H0MMYbKg@mail.gmail.com>
On 28/01/2022 12:47, Rao G wrote:
> Attempting to Read SPIBAR 0x10 from BUS 0 Dev 1F Func 5
>
> >>
> ScSpiBar0 = MmioRead32 (SpiInstance->PchSpiBase +
> PCI_BASE_ADDRESSREG_OFFSET) & 0xFFFFF000;
> >>
>
> The above code is throwing exception
>
> PchSpiBase at 0xC00FD000
> !!!! X64 Exception Type - 0E(#PF - Page-Fault) CPU Apic ID - 00000000 !!!!
> ExceptionData - 0000000000000000 I:0 R:0 U:0 W:0 P:0 PK:0 SS:0 SGX:0
> RIP - 00000000771903D0, CS - 0000000000000038, RFLAGS - 0000000000010046
>
> From the shell the value at offset 0x10 is 0xFE010000
>
> Any clues on why the processor is throwing exception while accessing the
> value PchSpiBase+0x10 ?
PCI_BASE_ADDRESSREG_OFFSET is an offset within PCI configuration space.
It looks as though you are trying to use an MMIO access to read from
PCI configuration space, which is not a valid thing to do.
I suspect you may want to use EFI_PCI_IO_PROTOCOL.Pci.Read() instead.
HTH,
Michael
next prev parent reply other threads:[~2022-01-28 12:59 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-28 12:47 Read SPI BAR offset 0x10 throwing processor exception Rao G
2022-01-28 12:59 ` Michael Brown [this message]
2022-01-28 13:08 ` [edk2-devel] " Rao G
2022-01-29 5:49 ` Jeff Fan
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