FreeBSD/Linux Kernel Cross Reference
sys/arm/broadcom/bcm2835/bcm2838_xhci.c

     /*-
      * SPDX-License-Identifier: ISC
      *
      * Copyright (c) 2020 Dr Robert Harvey Crowston <crowston@protonmail.com>
      *
      * Permission to use, copy, modify, and distribute this software for any
      * purpose with or without fee is hereby granted, provided that the above
      * copyright notice and this permission notice appear in all copies.
      *
     * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     *
     *
     * $FreeBSD$
     *
     */
    
    /*
     * VIA VL805 controller on the Raspberry Pi 4.
     * The VL805 is a generic xhci controller. However, in the newer hardware
     * revisions of the Raspberry Pi 4, it is incapable of loading its own firmware.
     * Instead, the VideoCore GPU must load the firmware into the controller at the
     * appropriate time. This driver is a shim that pre-loads the firmware before
     * handing control to the xhci generic driver.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/stdint.h>
    #include <sys/stddef.h>
    #include <sys/param.h>
    #include <sys/queue.h>
    #include <sys/types.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/bus.h>
    #include <sys/module.h>
    #include <sys/lock.h>
    #include <sys/mutex.h>
    #include <sys/condvar.h>
    #include <sys/sysctl.h>
    #include <sys/sx.h>
    #include <sys/unistd.h>
    #include <sys/callout.h>
    #include <sys/malloc.h>
    #include <sys/priv.h>
    
    #include <dev/usb/usb.h>
    #include <dev/usb/usbdi.h>
    
    #include <dev/usb/usb_core.h>
    #include <dev/usb/usb_busdma.h>
    #include <dev/usb/usb_process.h>
    #include <dev/usb/usb_util.h>
    
    #include <dev/usb/usb_controller.h>
    #include <dev/usb/usb_bus.h>
    #include <dev/usb/usb_pci.h>
    #include <dev/usb/controller/xhci.h>
    
    #include <dev/ofw/openfirm.h>
    #include <dev/ofw/ofw_bus.h>
    #include <dev/ofw/ofw_bus_subr.h>
    
    #include <arm/broadcom/bcm2835/bcm2835_mbox_prop.h>
    
    #define VL805_FIRMWARE_REG      0x50
    #define PCIE_BUS_SHIFT          20
    #define PCIE_SLOT_SHIFT         15
    #define PCIE_FUNC_SHIFT         12
    
    static int
    bcm_xhci_probe(device_t dev)
    {
            phandle_t root;
            uint32_t device_id;
    
            device_id = pci_get_devid(dev);
            if (device_id != 0x34831106) /* VIA VL805 USB 3.0 controller. */
                    return (ENXIO);
    
            /*
             * The VIA chip is not unique to the Pi, but we only want to use this
             * driver if the SoC is a Raspberry Pi 4. Walk the device tree to
             * discover if the system is a Pi 4.
             */
            root = OF_finddevice("/");
            if (root == -1)
                    return (ENXIO);
            if (!ofw_bus_node_is_compatible(root, "raspberrypi,4-model-b"))
                    return (ENXIO);
    
            /*
            * On the Pi 4, the VIA chip with the firmware-loading limitation is
            * soldered-on to a particular bus/slot/function. But, it's possible a
            * user could desolder the VIA chip, replace it with a pci-pci bridge,
            * then plug in a commodity VIA PCI-e card on the new bridge. In that
            * case we don't want to try to load the firmware to a commodity
            * expansion card.
            */
           if (pci_get_bus(dev) != 1 || pci_get_slot(dev) != 0 ||
               pci_get_function(dev) != 0 )
                   return (ENXIO);
   
           device_set_desc(dev,
               "VL805 USB 3.0 controller (on the Raspberry Pi 4b)");
   
           return (BUS_PROBE_SPECIFIC);
   }
   
   static uint32_t
   bcm_xhci_check_firmware(device_t dev, bool expect_loaded)
   {
           uint32_t revision;
           bool loaded;
   
           revision = pci_read_config(dev, VL805_FIRMWARE_REG, 4);
           loaded = !(revision == 0 || revision == 0xffffffff);
   
           if (expect_loaded && !loaded)
                   device_printf(dev, "warning: xhci firmware not found.\n");
           else if (bootverbose && !loaded)
                   device_printf(dev, "note: xhci firmware not found.\n");
           else if (bootverbose)
                   device_printf(dev,
                       "note: xhci firmware detected; firmware is revision %x.\n",
                        revision);
   
           if (!loaded)
                   return 0;
   
           return (revision);
   }
   
   static void
   bcm_xhci_install_xhci_firmware(device_t dev)
   {
           uint32_t revision, dev_addr;
           int error;
   
           revision = bcm_xhci_check_firmware(dev, false);
           if (revision > 0) {
                   /*
                    * With the pre-June 2020 boot firmware, it does not seem
                    * possible to reload already-installed xhci firmware.
                    */
                   return;
           }
   
           /*
            * Notify the VideoCore gpu processor that it needs to reload the xhci
            * firmware into the xhci controller. This needs to happen after the pci
            * bridge topology is registered with the controller.
            */
           if (bootverbose)
                   device_printf(dev, "note: installing xhci firmware.\n");
   
           dev_addr =
               pci_get_bus(dev)      << PCIE_BUS_SHIFT |
               pci_get_slot(dev)     << PCIE_SLOT_SHIFT |
               pci_get_function(dev) << PCIE_FUNC_SHIFT;
   
           error = bcm2835_mbox_notify_xhci_reset(dev_addr);
           if (error)
                   device_printf(dev,
                       "warning: xhci firmware install failed (error %d).\n",
                       error);
   
           DELAY(1000);
           bcm_xhci_check_firmware(dev, true);
   
           return;
   }
   
   static int
   bcm_xhci_attach(device_t dev)
   {
           struct xhci_softc *sc;
           int error;
   
           sc = device_get_softc(dev);
   
           bcm_xhci_install_xhci_firmware(dev);
   
           error = xhci_pci_attach(dev);
           if (error)
                   return (error);
   
           /* 32 bit DMA is a limitation of the PCI-e controller, not the VL805. */
           sc->sc_bus.dma_bits = 32;
           if (bootverbose)
                   device_printf(dev, "note: switched to 32-bit DMA.\n");
   
           return (0);
   }
   
   /*
    * Device method table.
    */
   static device_method_t bcm_xhci_methods[] = {
           /* Device interface. */
           DEVMETHOD(device_probe,                 bcm_xhci_probe),
           DEVMETHOD(device_attach,                bcm_xhci_attach),
   
           DEVMETHOD_END,
   };
   
   DEFINE_CLASS_1(bcm_xhci, bcm_xhci_driver, bcm_xhci_methods,
       sizeof(struct xhci_softc), xhci_pci_driver);
   
   DRIVER_MODULE(bcm_xhci, pci, bcm_xhci_driver, 0, 0);
   MODULE_DEPEND(bcm_xhci, usb, 1, 1, 1);

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