[PATCH] usb: bootm: Drop old USB-device-removal code
Mattijs Korpershoek
mkorpershoek at baylibre.com
Tue Jul 30 11:20:47 CEST 2024
Hi Simon,
Thank you for the patch.
On ven., juil. 26, 2024 at 06:36, Simon Glass <sjg at chromium.org> wrote:
> USB is stopped using driver model now, in dm_remove_devices_flags() in
> announce_and_cleanup() at the top of this file.
>
> The usb_stop() call actually unbinds devices.
>
> When a USB device is unbound, it causes any bootflows attached to it to
> be removed, via a call to bootdev_clear_bootflows() from
> bootdev_pre_unbind(). This obviously makes it impossible to boot the
> bootflow.
>
> However, when booting a bootflow that relies on USB, usb_stop() is
> called, which unbinds the device. At that point any information
> attached to the bootflow is dropped.
>
> This is quite risky since the contents of freed memory are not
> guaranteed to remain unchanged. Depending on what other options are
> done before boot, a hard-to-find bug may crop up.
>
> Drop the call to this old function.
>
> Leave the netconsole call there, since this needs conversion to
> driver model.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> Suggested-by: Shantur Rathore <i at shantur.com>
Reviewed-by: Mattijs Korpershoek <mkorpershoek at baylibre.com>
> ---
> The original patch was here:
> https://patchwork.ozlabs.org/project/uboot/patch/
> 20231119121144.v5.5.If206027372f73ce32480223e5626f4b944e281b7 at changeid/
>
> boot/bootm.c | 12 ------------
> 1 file changed, 12 deletions(-)
>
> diff --git a/boot/bootm.c b/boot/bootm.c
> index 376d63aafc9..480f8e6a0e6 100644
> --- a/boot/bootm.c
> +++ b/boot/bootm.c
> @@ -740,18 +740,6 @@ ulong bootm_disable_interrupts(void)
> eth_halt();
> #endif
>
> -#if defined(CONFIG_CMD_USB)
> - /*
> - * turn off USB to prevent the host controller from writing to the
> - * SDRAM while Linux is booting. This could happen (at least for OHCI
> - * controller), because the HCCA (Host Controller Communication Area)
> - * lies within the SDRAM and the host controller writes continously to
> - * this area (as busmaster!). The HccaFrameNumber is for example
> - * updated every 1 ms within the HCCA structure in SDRAM! For more
> - * details see the OpenHCI specification.
> - */
> - usb_stop();
> -#endif
> return iflag;
> }
>
> --
> 2.34.1
More information about the U-Boot
mailing list