RE: [PATCH rtw-next 2/2] wifi: rtw88: usb: Upload the firmware in bigger chunks

[Ping-Ke Shih <pkshih@realtek.com>]

: Bitterblue Smith <rtl8821cerfe2@gmail.com> wrote:
> RTL8811AU stops responding during the firmware download on some systems:
> 
> [  809.256440] rtw_8821au 5-2.1:1.0: Firmware version 42.4.0, H2C version 0
> [  812.759142] rtw_8821au 5-2.1:1.0 wlp48s0f4u2u1: renamed from wlan0
> [  837.315388] rtw_8821au 1-4:1.0: write register 0x1ef4 failed with -110
> [  867.524259] rtw_8821au 1-4:1.0: write register 0x1ef8 failed with -110
> [  868.930976] rtw_8821au 5-2.1:1.0 wlp48s0f4u2u1: entered promiscuous mode
> [  897.730952] rtw_8821au 1-4:1.0: write register 0x1efc failed with -110
> 
> Maybe it takes too long when writing the firmware 4 bytes at a time.
> 
> Write 196 bytes at a time for RTL8821AU, RTL8811AU, and RTL8812AU,
> and 254 bytes at a time for RTL8723DU. These are the sizes used in
> their official drivers. Tested with all these chips.
> 
> Cc: stable@vger.kernel.org
> Link: https://github.com/lwfinger/rtw88/issues/344
> Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>

Acked-by: Ping-Ke Shih <pkshih@realtek.com>

[..]

> diff --git a/drivers/net/wireless/realtek/rtw88/usb.c b/drivers/net/wireless/realtek/rtw88/usb.c
> index b16db579fdce..ad15ce12ab7f 100644
> --- a/drivers/net/wireless/realtek/rtw88/usb.c
> +++ b/drivers/net/wireless/realtek/rtw88/usb.c
> @@ -165,6 +165,60 @@ static void rtw_usb_write32(struct rtw_dev *rtwdev, u32 addr, u32 val)
>         rtw_usb_write(rtwdev, addr, val, 4);
>  }
> 
> +static void rtw_usb_write_firmware_page(struct rtw_dev *rtwdev, u32 page,
> +                                       const u8 *data, u32 size)
> +{
> +       struct rtw_usb *rtwusb = rtw_get_usb_priv(rtwdev);
> +       struct usb_device *udev = rtwusb->udev;
> +       u32 addr = FW_8192C_START_ADDRESS;

FW_8192C_START_ADDRESS is existing already. But something like
RTW_USB_FW_START_ADDRESS would be better. 

> +       u8 *data_dup, *buf;
> +       u32 n, block_size;
> +       int ret;
> +
> +       switch (rtwdev->chip->id) {
> +       case RTW_CHIP_TYPE_8723D:
> +               block_size = 254;
> +               break;
> +       default:
> +               block_size = 196;
> +               break;
> +       }
> +
> +       data_dup = kmemdup(data, size, GFP_KERNEL);

This is because type of argument `data` of usb_control_msg() is not const, right?
Do you know if usb_control_msg() will actually modify the data?