[PATCH 2/2] usb: xhci: Load Raspberry Pi 4 VL805's firmware

[Marek Vasut]

On 4/29/20 2:36 PM, Nicolas Saenz Julienne wrote:
> On Wed, 2020-04-29 at 14:05 +0200, Marek Vasut wrote:
>> On 4/29/20 12:10 PM, Nicolas Saenz Julienne wrote:
>>> On Tue, 2020-04-28 at 19:59 +0200, Marek Vasut wrote:
>>>> On 4/28/20 7:44 PM, Nicolas Saenz Julienne wrote:
>>>>> When needed, RPi4's co-processor (called VideoCore) has to be instructed
>>>>> to load VL805's firmware (the chip providing xHCI support). VideCore's
>>>>> firmware expects the board's PCIe bus to be already configured in order
>>>>> for it to load the xHCI chip firmware. So we have to make sure this
>>>>> happens in between the PCIe configuration and xHCI startup.
>>>>>
>>>>> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne at suse.de>
>>>>> ---
>>>>>  drivers/usb/host/xhci-pci.c | 6 ++++++
>>>>>  1 file changed, 6 insertions(+)
>>>>>
>>>>> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
>>>>> index c1f60da541..5c17ea6932 100644
>>>>> --- a/drivers/usb/host/xhci-pci.c
>>>>> +++ b/drivers/usb/host/xhci-pci.c
>>>>> @@ -11,6 +11,8 @@
>>>>>  #include <usb.h>
>>>>>  #include <usb/xhci.h>
>>>>>  
>>>>> +#include <asm/arch/msg.h>
>>>>> +
>>>>>  static void xhci_pci_init(struct udevice *dev, struct xhci_hccr
>>>>> **ret_hccr,
>>>>>  			  struct xhci_hcor **ret_hcor)
>>>>>  {
>>>>> @@ -18,6 +20,10 @@ static void xhci_pci_init(struct udevice *dev, struct
>>>>> xhci_hccr **ret_hccr,
>>>>>  	struct xhci_hcor *hcor;
>>>>>  	u32 cmd;
>>>>>  
>>>>> +#ifdef CONFIG_BCM2711
>>>>> +	bcm2711_load_vl805_firmware();
>>>>> +#endif
>>>>> +
>>>>>  	hccr = (struct xhci_hccr *)dm_pci_map_bar(dev,
>>>>>  			PCI_BASE_ADDRESS_0, PCI_REGION_MEM);
>>>>>  	hcor = (struct xhci_hcor *)((uintptr_t) hccr +
>>>>
>>>> I think socfpga arria10 has some firmware loader implementation that is
>>>> generic, so can't we use that ?
>>>
>>> I don't think so. I've been told the firmware upgrade protocol is private
>>> and
>>> specific to the VL80X family of devices. The Raspberry Pi foundation decided
>>> to
>>> implement it in their closed source VideoCore firmware.
>>
>> What I meant was that U-Boot has a way to load files from various
>> storage roughly the same way Linux firmware loader API does.
> 
> As far as generic APIs are concerned I've had a look at
> request_firmware_into_buf() which socfpga uses in its spl_board_init(). But
> sadly it doesn't help here.
> 
> What bcm2711_load_vl805_firmware() does here is just informing the co-processor
> that it's free to start the VL805 firmware load operation. I'm by no means
> providing anything, think of it as a doorbell if you will. I'll try to find an
> alternative to 'load' in the function name so the distinction with regular
> firmware loading is more explicit.

Oh, that's how it is, I see.

> Also bare in mind we have to time this operation in between PCIe configuration
> and xHCI init. Which, IIUC, blocks us from using board_init() and the likes of
> it (which would be way nicer IMO).

Maybe you need some callback there ?