On 13.08.2018 09:30, Gerard Salvatella wrote: > Some boards require specific configuration prior to booting the kernel. > For instance, our boards require shutting down the display to avoid > fading transitions before the drivers are reloaded by the kernel. This > could be facilitated by adding an extra hook during the os booting > process.
Maybe I can extend on what we are trying to achieve here: We enable display backlight using board code. The architecture code then shuts down the display controller just before booting Linux (e.g. on i.MX, by calling ipuv3_fb_shutdown/lcdif_power_down in arch_preboot_os). This leads to a display which has backlight enabled, but no data driven... Depending on display this leads to noisy/fading transitions between U-Boot and Linux. So we would like to disable the backlight in board code. In a first version we used a weak display_shutdown() function, but with that we would have to add it to every architecture. This approach uses a generic board specific preeboot_os callback which can be used for different purpose too. Does this sound like an approach which is acceptable upstream? -- Stefan > > Signed-off-by: Gerard Salvatella <[email protected]> > --- > common/bootm_os.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/common/bootm_os.c b/common/bootm_os.c > index f4bd905909..1e7af56b64 100644 > --- a/common/bootm_os.c > +++ b/common/bootm_os.c > @@ -505,9 +505,16 @@ __weak void arch_preboot_os(void) > /* please define platform specific arch_preboot_os() */ > } > > +/* Allow for board specific config before we boot */ > +__weak void board_preboot_os(void) > +{ > + /* please define board specific board_preboot_os() */ > +} > + > int boot_selected_os(int argc, char * const argv[], int state, > bootm_headers_t *images, boot_os_fn *boot_fn) > { > + board_preboot_os(); > arch_preboot_os(); > boot_fn(state, argc, argv, images); > > -- > 2.18.0 > > > [Toradex Logo]<http://toradex.com> Global Leader in Arm® > Embedded Computer Modules > > Choose > Us<https://www.toradex.com/how-to-choose-system-computer-on-module-partner> > | Products<https://www.toradex.com/products> | Developer > Center<http://developer.toradex.com/> | > Community<https://www.toradex.com/community> | > Careers<https://careers.toradex.com/> > Meet our engineers > at<https://www.toradex.com/events>:<https://www.toradex.com/events> > - Linux Developer Conference, Brazil, Aug 25-26, 2018 > - NXP Technology Days 2018, United States, Aug 28, 2018 > - IoT Latin America, Brazil, Aug 29-30, 2018 > > > > _______________________________________________ > U-Boot mailing list > [email protected] > https://lists.denx.de/listinfo/u-boot _______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
