Hi, I'm sending firmware to usb device with this code: But it`s falling because the request firmware call didn't put my firmware in a DMA capable area. That's my guess. So how to request firmware in DMA capable area? Thanks Lucas [   30.330081] ------------[ cut here ]------------ [   30.334782] WARNING: CPU: 1 PID: 557 at /media/workspace/linux/drivers/usb/core/hcd.c:1586 usb_hcd_map_urb_for_dma+0x4f4/0x634 [   30.346362] transfer buffer not dma capable [   30.350623] Modules linked in: usb_bridge_boot(+) bnep hci_uart btbcm serdev bluetooth ecdh_generic 8021q garp stp llc bcm2835_codec(C) brcmfmac vc4 brcmutil v4l6 [   30.406130] CPU: 1 PID: 557 Comm: systemd-udevd Tainted: G         C        4.19.108-v7l+ #1 [   30.414691] Hardware name: BCM2835 [   30.418148] [<c0212c6c>] (unwind_backtrace) from [<c020d490>] (show_stack+0x20/0x24) [   30.426009] [<c020d490>] (show_stack) from [<c09c1ac0>] (dump_stack+0xd8/0x11c) [   30.433428] [<c09c1ac0>] (dump_stack) from [<c0222138>] (__warn+0xf0/0x108) [   30.440492] [<c0222138>] (__warn) from [<c02221a8>] (warn_slowpath_fmt+0x58/0x74) [   30.448087] [<c02221a8>] (warn_slowpath_fmt) from [<c079df38>] (usb_hcd_map_urb_for_dma+0x4f4/0x634) [   30.457357] [<c079df38>] (usb_hcd_map_urb_for_dma) from [<c079e518>] (usb_hcd_submit_urb+0x4a0/0x968) [   30.466714] [<c079e518>] (usb_hcd_submit_urb) from [<c079fbfc>] (usb_submit_urb+0x354/0x504) [   30.475277] [<c079fbfc>] (usb_submit_urb) from [<c07a0430>] (usb_start_wait_urb+0x6c/0xf0) [   30.483663] [<c07a0430>] (usb_start_wait_urb) from [<c07a0588>] (usb_control_msg+0xd4/0x12c) [   30.492232] [<c07a0588>] (usb_control_msg) from [<bf984270>] (clbrd_probe+0x240/0x43c [usb_bridge_boot]) [   30.502135] [<bf984270>] (clbrd_probe [usb_bridge_boot]) from [<c07a4f64>] (usb_probe_interface+0xec/0x278) [   30.512287] [<c07a4f64>] (usb_probe_interface) from [<c071a4d8>] (really_probe+0x1e8/0x2d0) [   30.520762] [<c071a4d8>] (really_probe) from [<c071a794>] (driver_probe_device+0x70/0x184) [   30.529149] [<c071a794>] (driver_probe_device) from [<c071a998>] (__driver_attach+0xf0/0xf4) [   30.537712] [<c071a998>] (__driver_attach) from [<c07183f4>] (bus_for_each_dev+0x84/0xc4) [   30.546011] [<c07183f4>] (bus_for_each_dev) from [<c0719ddc>] (driver_attach+0x2c/0x30) [   30.554133] [<c0719ddc>] (driver_attach) from [<c07197bc>] (bus_add_driver+0x19c/0x220) [   30.562254] [<c07197bc>] (bus_add_driver) from [<c071b184>] (driver_register+0x84/0x118) [   30.570464] [<c071b184>] (driver_register) from [<c07a3d84>] (usb_register_driver+0x80/0x144) [   30.579117] [<c07a3d84>] (usb_register_driver) from [<bf989030>] (clbrd_driver_init+0x30/0x1000 [usb_bridge_boot]) [   30.589889] [<bf989030>] (clbrd_driver_init [usb_bridge_boot]) from [<c0203138>] (do_one_initcall+0x50/0x214) [   30.600218] [<c0203138>] (do_one_initcall) from [<c02bdcb8>] (do_init_module+0x74/0x224) [   30.608429] [<c02bdcb8>] (do_init_module) from [<c02bcce8>] (load_module+0x202c/0x25dc) [   30.616552] [<c02bcce8>] (load_module) from [<c02bd4d8>] (sys_finit_module+0xbc/0xe8) [   30.624497] [<c02bd4d8>] (sys_finit_module) from [<c02011a4>] (__sys_trace_return+0x0/0x1c) [   30.632969] Exception stack(0xdafdffa8 to 0xdafdfff0) [   30.638091] ffa0:                   fda1c800 01e30b08 00000006 b6d8f8e0 00000000 b6d903f4 [   30.646388] ffc0: fda1c800 01e30b08 00000000 0000017b 01e5c418 0057f1dc 01e5d0c8 00000000 [   30.654684] ffe0: bea80180 bea80170 b6d869d8 b6e76af0 [   30.659823] ---[ end trace fa96d8b137009b49 ]--- static int fx3_ram_write(struct usb_device *udev, u32 *buf, u32 ramAddress, size_t len) {     size_t index = 0, size;     int ret;     while(len > 0) {         size = (len > MAX_WRITE_SIZE) ? MAX_WRITE_SIZE : len;         ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0xA0, 0x40,                       ramAddress & 0xFFFF, ramAddress >> 16,                       &buf[index], size, VENDORCMD_TIMEOUT);         if (ret != size) {             ret = (ret < 0) ? ret : -EIO;             dev_err(&udev->dev, "Error: Vendor write to FX3 RAM failed: %d\n", ret);             return ret;         }         ramAddress += size;         index      += size;         len        -= size;     }     return 0; } static int clbrd_probe(struct usb_interface *intf,                const struct usb_device_id *id) {     struct device *dev = &intf->dev;     struct usb_device *udev = interface_to_usbdev(intf);     const struct firmware *firmware;     struct fx3_img *img;     struct fx3_sector *sector;     int ret;     dev_info(&intf->dev, "%s\n", __func__);     ret = request_firmware(&firmware, FW_NAME, dev);     if (ret)         dev_err(dev, "request_firmware failed '%s' = %d (check files)\n", FW_NAME, ret);     img = (struct fx3_img*)firmware->data;     print_img_header(dev, img);     sector = (struct fx3_sector*)img->sectors;     while ((u8*)sector < firmware->data + firmware->size) {         dev_dbg(&intf->dev, "0x%.4x 0x%.4x\n", sector->dLength , sector->dAddress);         if (sector->dLength == 0) {             ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),                           0xA0, 0x40,                           (sector->dAddress & 0xFFFF),                           (sector->dAddress >> 16),                           NULL, 0, VENDORCMD_TIMEOUT);             if (ret < 0)                 dev_err(dev, "Fail to write last sector: %d\n", ret);             break;         }         ret = fx3_ram_write(udev, sector->dData, sector->dAddress, sector->dLength * 4);         if (ret < 0)             dev_err(dev, "Fail to write sector: %d\n", ret);         sector +=  sizeof(sector->dLength) + sizeof(sector->dAddress) + (sector->dLength * 4);     }     release_firmware(firmware);     return ret; }