[U-Boot] [PATCH 03/11] usb: ehci: generic PCI support

[Vincent Palatin]

On Thu, Dec 13, 2012 at 9:30 AM, Marek Vasut <marex at denx.de> wrote:
> Dear Simon Glass,
>
>> From: Vincent Palatin <vpalatin at chromium.org>
>>
>> Instead of hardcoding the PCI IDs on the USB controller, use the PCI
>> class to detect them.
>>
>> Ensure the busmaster bit is properly set in the PCI configuration.
>>
>> Signed-off-by: Simon Glass <sjg at chromium.org>
>> ---
>>  drivers/usb/host/ehci-pci.c |   37 +++++++++++++++++++++++++++++++++++++
>>  1 files changed, 37 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
>> index 29af02d..0dc0e6e 100644
>> --- a/drivers/usb/host/ehci-pci.c
>> +++ b/drivers/usb/host/ehci-pci.c
>> @@ -32,6 +32,34 @@ static struct pci_device_id ehci_pci_ids[] = {
>>       {0x12D8, 0x400F},       /* Pericom */
>>       {0, 0}
>>  };
>> +#else
>> +static pci_dev_t ehci_find_class(void)
>> +{
>> +     int bus;
>> +     int devnum;
>> +     pci_dev_t bdf;
>> +     uint32_t class;
>> +
>> +     for (bus = 0; bus < pci_last_busno(); bus++) {
>> +             for (devnum = 0; devnum < PCI_MAX_PCI_DEVICES-1; devnum++) {
>> +                     pci_read_config_dword(PCI_BDF(bus, devnum, 0),
>> +                                           PCI_CLASS_REVISION, &class);
>> +                     if (class >> 16 == 0xffff)
>> +                             continue;
>> +
>> +                     for (bdf = PCI_BDF(bus, devnum, 0);
>> +                                     bdf <= PCI_BDF(bus, devnum,
>> +                                             PCI_MAX_PCI_FUNCTIONS - 1);
>> +                                     bdf += PCI_BDF(0, 0, 1)) {
>> +                             pci_read_config_dword(bdf, PCI_CLASS_REVISION,
>> +                                                   &class);
>> +                             if (class >> 8 == 0x0c0320)
>
> Can we at least describe this magic please?

The PCI class word is something like that :
class = [31:24] class code [23:16] subclass [15:8] Prog if [7:0] Revision ID
For this use case :
class code = 0x0C (Serial bus controller)
subclass = 0x03 (USB controller)
Program interface = 0x20 (EHCI)

This is available in include/pci_ids.h as "#define
PCI_CLASS_SERIAL_USB_EHCI       0x0c0320"
so just replacing the numeric constant by this define should be ok ?

>> +                                     return bdf;
>> +                     }
>> +             }
>> +     }
>> +     return -1;
>
> Let's try to use errno.h please. It won't be consistent for a while, but we'll
> get there.
>
>> +}
>>  #endif
>>
>>  /*
>> @@ -41,8 +69,13 @@ static struct pci_device_id ehci_pci_ids[] = {
>>  int ehci_hcd_init(int index, struct ehci_hccr **hccr, struct ehci_hcor
>> **hcor) {
>>       pci_dev_t pdev;
>> +     uint32_t cmd;
>>
>> +#ifdef CONFIG_PCI_EHCI_DEVICE
>>       pdev = pci_find_devices(ehci_pci_ids, CONFIG_PCI_EHCI_DEVICE);
>> +#else
>> +     pdev = ehci_find_class();
>> +#endif
>>       if (pdev == -1) {
>>               printf("EHCI host controller not found\n");
>>               return -1;
>> @@ -57,6 +90,10 @@ int ehci_hcd_init(int index, struct ehci_hccr **hccr,
>> struct ehci_hcor **hcor) (uint32_t)*hccr, (uint32_t)*hcor,
>>                       (uint32_t)HC_LENGTH(ehci_readl(&(*hccr)->cr_capbase)));
>>
>> +     /* enable busmaster */
>> +     pci_read_config_dword(pdev, PCI_COMMAND, &cmd);
>> +     cmd |= PCI_COMMAND_MASTER;
>> +     pci_write_config_dword(pdev, PCI_COMMAND, cmd);
>>       return 0;
>>  }
>
> Best regards,
> Marek Vasut