[U-Boot] Device tree & PCI/ECAM questions

[Aaron Williams]

Hi all,

I am working on several drivers for our Octeon-TX/Thunder chips which 
talk to devices connected to the ECAM bus through another sub-bus and am 
having issues regarding the device tree.

We have a "PCI" driver to handle the ECAM and I created a simple-bus 
stub for our MRML bus which connects low-speed devices to the ECAM bus 
and all of the devices show up in the device tree.

My problem is that the devices also enumerated via PCI.

I have something like the following:

static int cavium_pci_mmc_probe(struct udevice *dev)
{
     debug("%s: Entry\n", __func__);
     pci_dev_t bdf = dm_pci_get_bdf(dev);
     struct cavium_mmc_host *host = dev_get_priv(dev);
     size_t size;
     uint64_t base_addr = dm_pci_map_bar(dev, 0, &size, PCI_REGION_MEM);
     int rc = 0;

     host->base_addr = base_addr;
     dev->req_seq = PCI_FUNC(bdf);

     debug("%s(%s): ", __func__, dev->name);
     debug("  platdata:        %p\n"
           "  parent platdata: %p\n"
           "  uclass platdata: %p\n"
           "  base address:    %lx\n"
           "  of_offset:       %d\n"
           "  parent:          %p\n"
           "  priv:            %p\n"
           "  uclass:          %p\n"
           "  req_seq:         %d\n"
           "  seq:             %d\n",
           dev->platdata, dev->parent_platdata,
           dev->uclass_platdata, base_addr,
           dev->of_offset, dev->parent, dev->priv,
           dev->uclass, dev->req_seq, dev->seq);

     if (dev->of_offset >= 0)
         rc = process_node(dev, gd->fdt_blob, dev->of_offset);

     return rc;
}

static const struct udevice_id cavium_mmc_ids[] = {
     { .compatible = "cavium,thunder-8890-mmc" },
     { .compatible = "cavium,mmc" },
     { },
};

static const struct udevice_id cavium_mmc_slot_ids[] = {
     { .compatible = "cavium,thunder-8890-mmc-slot" },
     { },
};

U_BOOT_DRIVER(cavium_pci_mmc) = {
     .name    = "mmc_cavium",
     .id    = UCLASS_MMC,
     .of_match = of_match_ptr(cavium_mmc_ids),
     .ofdata_to_platdata = cavium_mmc_ofdata_to_platdata,
     .probe    = cavium_pci_mmc_probe,
     .priv_auto_alloc_size = sizeof(struct cavium_mmc_host),
     .ops = NULL,
};

static struct pci_device_id cavium_pci_mmc_supported[] = {
     { PCI_VDEVICE(CAVIUM, PCI_DEVICE_ID_THUNDER_MMC) },
     {},
};

U_BOOT_PCI_DEVICE(cavium_pci_mmc, cavium_pci_mmc_supported);

The problem I'm seeing is that in the probe function the of_offset field 
is always -1. Shouldn't it resolve this information via the compatible 
string in the device tree? How should I go about setting it up so that 
not only things like the base address get resolved but also the 
of_offset field since all of the slot configuration comes from the 
device tree.

In our case we have a single MMC device on the MRML bus connected to the 
ECAM bus (which looks like a PCI bus) which supports multiple slots with 
one set of registers.

-Aaron

-- 
Aaron Williams
Software Engineer
Cavium, Inc.
(408) 943-7198  (510) 789-8988 (cell)