On 2015年06月04日 18:22, Lorenzo Pieralisi wrote:
Hi Hanjun,
On Thu, Jun 04, 2015 at 10:28:17AM +0100, Hanjun Guo wrote:
Hi Lorenzo,
On 2015???06???02??? 21:32, Lorenzo Pieralisi wrote:
On Wed, May 27, 2015 at 09:06:26AM +0100, Tomasz Nowicki wrote:
On 26.05.2015 19:08, Will Deacon wrote:
On Tue, May 26, 2015 at 01:49:18PM +0100, Hanjun Guo wrote:
From: Tomasz Nowicki <tomasz.nowicki@xxxxxxxxxx>
ECAM standard and MCFG table are architecture independent and it makes
sense to share common code across all architectures. Both are going to
corresponding files - ecam.c and mcfg.c
While we are here, rename pci_parse_mcfg to acpi_parse_mcfg.
We already have acpi_parse_mcfg prototype which is used nowhere.
At the same time, we need pci_parse_mcfg been global so acpi_parse_mcfg
can be used perfectly here.
Signed-off-by: Tomasz Nowicki <tomasz.nowicki@xxxxxxxxxx>
Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
---
arch/x86/Kconfig | 3 +
arch/x86/include/asm/pci_x86.h | 33 ------
arch/x86/pci/acpi.c | 1 +
arch/x86/pci/mmconfig-shared.c | 244 +---------------------------------------
arch/x86/pci/mmconfig_32.c | 1 +
arch/x86/pci/mmconfig_64.c | 1 +
arch/x86/pci/numachip.c | 1 +
drivers/acpi/Makefile | 1 +
drivers/acpi/mcfg.c | 57 ++++++++++
drivers/pci/Kconfig | 7 ++
drivers/pci/Makefile | 5 +
drivers/pci/ecam.c | 245 +++++++++++++++++++++++++++++++++++++++++
Why can't we make use of the ECAM implementation used by pci-host-generic
and drivers/pci/access.c?
We had that question when I had posted MMCFG patch set separately,
please see:
https://lkml.org/lkml/2015/3/11/492
Yes, but the real question is, why do we need to have PCI config space
up and running before a bus struct is even created ? I think the reason is
the PCI configuration address space format (ACPI 6.0, Table 5-27, page
108):
"PCI Configuration space addresses must be confined to devices on
PCI Segment Group 0, bus 0. This restriction exists to accommodate
access to fixed hardware prior to PCI bus enumeration".
On HW reduced platforms I do not even think this is required at all,
we have to look into this to avoid code duplication that might well
turn out useless.
This is only for the fixed hardware, which will be not available for
ARM64 (reduced hardware mode), but in Generic Hardware Programming
Model, we using OEM-provided ACPI Machine Language (AML) code to access
generic hardware registers, this will be available for reduced hardware
too.
So in ACPI spec, it says: (ACPI 6.0 page 66, last paragraph)
ACPI defines eight address spaces that may be accessed by generic
hardware implementations. These include:
* System I/O space
* System memory space
* PCI configuration space
* Embedded controller space
* System Management Bus (SMBus) space
* CMOS
* PCI BAR Target
* IPMI space
So if any device using the PCI address space for control, such
as a system reset control device, its address space can be reside
in PCI configuration space (who can prevent a OEM do that crazy
thing? :) ), and it should be accessible before the PCI bus is
created.
Us, by changing attitude and questioning features whose usefulness
is questionable. I will look into this and raise the point, I am not
thrilled by the idea of adding another set of PCI accessor functions
and drivers because we have to access a register through PCI before
enumerating the bus (and on arm64 this is totally useless since
we are not meant to support fixed HW anyway). Maybe we can make acpica
code use a "special" stub (ACPI specific, PCI configuration space address
space has restrictions anyway), I have to review this set in its
entirety to see how to do that (and I would kindly ask you to do
it too, before saying it is not possible to implement it).
I'm willing to do that, actually, if we don't need a mechanism to
access PCI config space before the bus is created, the code can be
simplified a lot.
Thanks for your help and patient.
Hanjun
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