From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Date: Thu, 08 Mar 2012 11:08:56 -0700 Subject: [U-Boot] ns16550: tegra: Specify debugging serial port at boot. In-Reply-To: <1325890269-5613-1-git-send-email-swarren@nvidia.com> References: <1325890269-5613-1-git-send-email-swarren@nvidia.com> Message-ID: <4F58F5B8.6070402@wwwdotorg.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 01/06/2012 05:51 AM, Stephen Warren wrote: > From: Doug Anderson > > This works together with a kernel change that looks at the scratchpad > register to determine which of the many UARTs it should use for early > printing: > > http://www.spinics.net/lists/arm-kernel/msg154633.html > > While it is unfortunate to need to pass this information in a second way > (it's already in the device tree), this does allow the very early boot > code (decompressing stub and early assembly code) to print to the right > port. > > At the moment, I'm adding this to the UART init function. Alternatively, > we could add a more complex patch to key off of the 'console' setting. > > Signed-off-by: Doug Anderson > [swarren: Limited the change to Tegra platforms] > Signed-off-by: Stephen Warren > Acked-by: Doug Anderson I noticed this patch isn't applied yet that I can find. Are there any comments on it; can it be applied? Thanks. For reference, it's in patchwork at: http://patchwork.ozlabs.org/patch/134712/ > --- > drivers/serial/ns16550.c | 7 +++++++ > 1 files changed, 7 insertions(+), 0 deletions(-) > > diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c > index 0c23955..19a28cd 100644 > --- a/drivers/serial/ns16550.c > +++ b/drivers/serial/ns16550.c > @@ -62,6 +62,13 @@ void NS16550_init(NS16550_t com_port, int baud_divisor) > serial_out(0, &com_port->mdr1); > #endif > #endif /* CONFIG_OMAP */ > +#if defined(CONFIG_TEGRA2) > + /* > + * Put a 'D' in the scratchpad to let the kernel know which UART > + * for earlyprintk [D]ebugging. > + */ > + serial_out('D', &com_port->spr); > +#endif > } > > #ifndef CONFIG_NS16550_MIN_FUNCTIONS