[U-Boot] [PATCH 1/9] dm: pci: return the real controller in pci_bus_to_hose()

[Bin Meng]

Hi Minghuan,

On Tue, Oct 11, 2016 at 3:12 PM, M.H. Lian <minghuan.lian at nxp.com> wrote:
> Hi Bin,
>
> With the patches our Layerscape PCIe driver has been fully based on DM.
> Ethernet driver E1000 needs to define "CONFIG_DM_ETH" to use PCIe DM API instead of legacy PCI API.
> But our other Ethernet driver FM(drivers/net/fm/eth.c) is still not support DM. So we cannot define "CONFIG_DM_ETH"

For LS1021a ethernet, please pick up this patch to see if it works:
http://patchwork.ozlabs.org/patch/566347/

> Well, we must define "CONFIG_DM_PCI_COMPAT" to support e1000 and fm at the same time.
> After FM driver is changed to support DM, we can define "CONFIG_DM_ETH" and remove  "CONFIG_DM_PCI_COMPAT "
>
> But the current DM driver has an issue.
>
> 1.
>  pci_bus_to_hose(int busnum)  defined in driver/pci/pci_compat.c  is to return the hose associated current busnum(PCIe device) instead of PCIe controller (RC)
>
> pci_bus_to_hose(int bus) defined in driver/pci/pci.c for legacy PCI driver is to return the hose pointed to the PCIe controller(RC).
>
> My first patch is to keep consistency and return the hose pointer of the PCIe controller.
> -       return dev_get_uclass_priv(bus);
> +       return dev_get_uclass_priv(pci_get_controller(bus));
>
> 2
>  In pci/pci_common.c phys_addr_t pci_hose_bus_to_phys()
>
> #ifdef CONFIG_DM_PCI
>        /* The root controller has the region information */
>        hose = pci_bus_to_hose(0);
> #endif
>
> Is always to return hose of the bus0.
>
> But our SoC has more than one PCIe controllers(RC).
>
> For example:
> PCI0 bus 0  --  e1000#0  bus1
> PCI1 bus 2  --  e1000#1  bus3.

I got it. But this does not look that good to me. There are two
controllers, and bus number should be relative to the controller
itself, not system wide. It's definitely right to assign bus number 0
to both PCIe host controllers, as they forward the bus number on their
own bus link. I am wondering we should add a controller number to the
PCI command, like the storage device command. The first parameter is
the controller number, while the second parameter is the bus number.

>
> PCI1 is the second PCIe controller (RC) has different PCIe space to PCI0.
> For E1000#1, we want to get the host pointed to PCI1 bus2 not bus0.
>

Regards,
Bin