[U-Boot] x86: Set up the PCI busses when initializing the coreboot "board"

U-boot needs a host controller or "hose" to interact with the PCI busses
behind them. This change installs a host controller during initialization
of the coreboot "board" which implements some of X86's basic PCI semantics.
This relies on some existing generic code, but also duplicates a little bit
of code from the sc520 implementation. Ideally we'd eliminate that
duplication at some point.

It looks like in order to scan buses beyond bus 0, we'll need to tell
u-boot's generic PCI configuration code what to do if it encounters a
bridge, specifically to scan the bus on the other side of it.

A hook is installed to configure PCI bus bridges as they encountered by
u-boot. The hook extracts the secondary bus number from the bridge's config
space and then recursively scans that bus.

Signed-off-by: Gabe Black <gabeblack@chromium.org>
---
 board/chromebook-x86/coreboot/coreboot_pci.c |   33 ++++++++++++++++++++++++++
 1 files changed, 33 insertions(+), 0 deletions(-)

Hi Gabe

On Tue, Dec 6, 2011 at 9:12 AM, Gabe Black <gabeblack@chromium.org> wrote:
> U-boot needs a host controller or "hose" to interact with the PCI busses
> behind them. This change installs a host controller during initialization
> of the coreboot "board" which implements some of X86's basic PCI semantics.
> This relies on some existing generic code, but also duplicates a little bit
> of code from the sc520 implementation. Ideally we'd eliminate that
> duplication at some point.

Then let's just do it now - PCI is very standardised and I see no reason
for the hose setup and scan to be too specific. If the case comes along
later that a SoC or board needs something specific, we can add hooks or
weaken the functions then. But for now, let's just create a standard
implementation in arch/c86/lib/pci.c

> It looks like in order to scan buses beyond bus 0, we'll need to tell
> u-boot's generic PCI configuration code what to do if it encounters a
> bridge, specifically to scan the bus on the other side of it.
>
> A hook is installed to configure PCI bus bridges as they encountered by
> u-boot. The hook extracts the secondary bus number from the bridge's config
> space and then recursively scans that bus.

Thanks! I think I am seeing this issue as well - Now I know how to deal
with it :)

>
> Signed-off-by: Gabe Black <gabeblack@chromium.org>
> ---
>  board/chromebook-x86/coreboot/coreboot_pci.c |   33 ++++++++++++++++++++++++++
>  1 files changed, 33 insertions(+), 0 deletions(-)
>
> diff --git a/board/chromebook-x86/coreboot/coreboot_pci.c b/board/chromebook-x86/coreboot/coreboot_pci.c
> index 732ca3c..2ec6059 100644
> --- a/board/chromebook-x86/coreboot/coreboot_pci.c
> +++ b/board/chromebook-x86/coreboot/coreboot_pci.c
> @@ -25,6 +25,39 @@
>  * MA 02111-1307 USA
>  */
>
> +#include <common.h>
> +#include <pci.h>
> +#include <asm/pci.h>
> +
> +static struct pci_controller coreboot_hose;
> +
> +#define X86_PCI_CONFIG_ADDR 0xCF8
> +#define X86_PCI_CONFIG_DATA 0xCFC

Not needed [1],[2] (I missed arch/x86/include/asm/arch-sc520/pci.h in
that patch so I'll fix that)

> +
> +static void config_pci_bridge(struct pci_controller *hose, pci_dev_t dev,
> +                             struct pci_config_table *table)
> +{
> +       u8 secondary;
> +       hose->read_byte(hose, dev, PCI_SECONDARY_BUS, &secondary);
> +       hose->last_busno = max(hose->last_busno, secondary);
> +       pci_hose_scan_bus(hose, secondary);
> +}
> +
> +static struct pci_config_table pci_coreboot_config_table[] = {
> +       /* vendor, device, class, bus, dev, func */
> +       { PCI_ANY_ID, PCI_ANY_ID, PCI_CLASS_BRIDGE_PCI,
> +         PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, &config_pci_bridge},

Looks like one too many PCI_ANY_ID's to me

> +       {}
> +};
> +
>  void pci_init_board(void)
>  {
> +       coreboot_hose.config_table = pci_coreboot_config_table;
> +       coreboot_hose.first_busno = 0;
> +       coreboot_hose.last_busno = 0;
> +       coreboot_hose.region_count = 0;
> +
> +       pci_setup_type1(&coreboot_hose);
> +       pci_register_hose(&coreboot_hose);
> +       pci_hose_scan(&coreboot_hose);

Is there a reason this is not:

	hose->last_busno = pci_hose_scan(hose);

I'm thinking that the presence of a bridge might confuse the issue. If so,
is there something we need to change to deal with it (i.e. does the U-Boot
PCI code in general have issues with PCI brdiges that needs to be dealt
with)?

>  }

[1]http://patchwork.ozlabs.org/patch/124348/
[2]http://git.denx.de/?p=u-boot.git;a=commitdiff;h=1cfcf0370132315d6eee375

Regards,

Graeme

On Monday 05 December 2011 17:12:30 Gabe Black wrote:
> --- a/board/chromebook-x86/coreboot/coreboot_pci.c
> +++ b/board/chromebook-x86/coreboot/coreboot_pci.c
>
> +static struct pci_config_table pci_coreboot_config_table[] = {

const ?
-mike