Re: [PATCH] usb: xhci-pci: Raspberry Pi FW loader for VIA VL805

[Stefan Wahren]

Hi Nicolas,

Am 17.02.20 um 11:07 schrieb Nicolas Saenz Julienne:
> On the Raspberry Pi 4, after a PCI reset, VL805's firmware may either be
> loaded directly from an EEPROM or, if not present, by the SoC's
> VideCore.  Inform VideCore that VL805 was just reset, or defer xhci's
> probe if not yet joinable trough the mailbox interface.
>
> Based on Tim Gover's downstream implementation.
>
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>
> ---
>  drivers/usb/host/xhci-pci.c                | 50 ++++++++++++++++++++++
>  include/soc/bcm2835/raspberrypi-firmware.h |  2 +-
>  2 files changed, 51 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
> index 4917c5b033fa..eadace4a9339 100644
> --- a/drivers/usb/host/xhci-pci.c
> +++ b/drivers/usb/host/xhci-pci.c
> @@ -13,6 +13,8 @@
>  #include <linux/module.h>
>  #include <linux/acpi.h>
>  
> +#include <soc/bcm2835/raspberrypi-firmware.h>
> +
>  #include "xhci.h"
>  #include "xhci-trace.h"
>  
> @@ -308,6 +310,44 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
>  	return xhci_pci_reinit(xhci, pdev);
>  }
>  
> +/*
> + * On the Raspberry Pi 4, after a PCI reset, VL805's firmware may either be
> + * loaded directly from an EEPROM or, if not present, by the SoC's VideCore.
> + * Inform VideCore that VL805 was just reset, or defer xhci's probe if not yet
> + * joinable trough the mailbox interface.
> + */
> +static int raspberrypi_load_vl805_fw(struct pci_dev *pdev)
> +{
> +#ifdef CONFIG_RASPBERRYPI_FIRMWARE
> +	struct device_node *fw_np;
> +	struct rpi_firmware *fw;
> +	u32 dev_addr;
> +	int ret;
> +
> +	fw_np = of_find_compatible_node(NULL, NULL,
> +					"raspberrypi,bcm2835-firmware");
> +	if (!fw_np)
> +		return 0;
> +
> +	fw = rpi_firmware_get(fw_np);
> +	of_node_put(fw_np);
> +	if (!fw)
> +		return -EPROBE_DEFER;
> +
> +	dev_addr = pdev->bus->number << 20 | PCI_SLOT(pdev->devfn) << 15 |
> +		   PCI_FUNC(pdev->devfn) << 12;
> +
> +	ret = rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_XHCI_RESET,
> +				    &dev_addr, sizeof(dev_addr));
> +	if (ret)
> +		return ret;
not sure, but there could be a corner case which should be handled
differently. In case the Raspberry Pi 4 has an EEPROM for the VL805
firmware but the firmware is too old to handle
RPI_FIRMWARE_NOTIFY_XHCI_RESET, we should return with 0. I don't know
there is a change to detect this reliable. I just want to mention this.
> +
> +	dev_dbg(&pdev->dev, "loaded Raspberry Pi's VL805 firmware\n");
> +
> +#endif
> +	return 0;
> +}
> +
>  /*
>   * We need to register our own PCI probe function (instead of the USB core's
>   * function) in order to create a second roothub under xHCI.
> @@ -321,6 +361,16 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
>  
>  	driver = (struct hc_driver *)id->driver_data;
>  
> +	if (dev->vendor == PCI_VENDOR_ID_VIA && dev->device == 0x3483) {
> +		retval = raspberrypi_load_vl805_fw(dev);
> +		if (retval) {
> +			if (retval != -EPROBE_DEFER)
> +				dev_err(&dev->dev,
> +					"Failed to load VL805's firmware");
> +			return retval;
> +		}
> +	}
> +
>  	/* Prevent runtime suspending between USB-2 and USB-3 initialization */
>  	pm_runtime_get_noresume(&dev->dev);
>  
> diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
> index 7800e12ee042..cc9cdbc66403 100644
> --- a/include/soc/bcm2835/raspberrypi-firmware.h
> +++ b/include/soc/bcm2835/raspberrypi-firmware.h
> @@ -90,7 +90,7 @@ enum rpi_firmware_property_tag {
>  	RPI_FIRMWARE_SET_PERIPH_REG =                         0x00038045,
>  	RPI_FIRMWARE_GET_POE_HAT_VAL =                        0x00030049,
>  	RPI_FIRMWARE_SET_POE_HAT_VAL =                        0x00030050,
> -
> +	RPI_FIRMWARE_NOTIFY_XHCI_RESET =                      0x00030058,

In past we updated the firmware mailbox property interface in a bunch as
a separate patch. So we can avoid those gaps.

Best regards
Stefan

>  
>  	/* Dispmanx TAGS */
>  	RPI_FIRMWARE_FRAMEBUFFER_ALLOCATE =                   0x00040001,