[5/5] tty: serial: Add 8250-core based omap driver

* Tony Lindgren <tony@atomide.com> [140717 23:28]:
> * Sebastian Andrzej Siewior <bigeasy@linutronix.de> [140717 03:09]:
> > On 07/17/2014 10:12 AM, Tony Lindgren wrote:
> > > Hmm it could be that it works for a while because the clocks are on
> > > from the bootloader and pm_runtime calls won't do anything. This
> > > could happen if the interconnect data based on the ti,hwmods entry
> > > is not getting matched to the new driver. This gets initialized when
> > > the device entry gets created in omap_device_build_from_dt().
> > > 
> > > Or maybe something now affects the clock aliases? It seems that we
> > > are still missing the clocks entries in the .dtsi files, see the
> > > mappings with $ git grep uart drivers/clk/ti/
> > 
> > I've been looking for something completely different while I noticed
> > this:
> > 
> > in drivers/tty/serial/omap-serial.c
> > | static struct platform_driver serial_omap_driver = {
> > |         .driver         = {
> > |                 .name   = DRIVER_NAME,
> > |         },
> > | };
> > |
> > 
> > and DRIVER_NAME should come from include/linux/platform_data/serial-omap.h
> > Looking further, I've found arch/arm/mach-omap2/serial.c:
> > | void __init omap_serial_init_port(struct omap_board_data *bdata,
> > |                         struct omap_uart_port_info *info)
> > | {
> > |         char *name
> > …
> > |	name = DRIVER_NAME;
> > …
> > |	pdev = omap_device_build(name, uart->num, oh, pdata, pdata_size);
> > …
> > |
> > 
> > Would this explain it?
> 
> That would explain it for legacy booting, but not for device tree
> based booting. I can try to debug it further on Monday.

Looks like the following is needed to avoid the error, no idea why..
But this is what we also do in omap-serial.c. It may be needed in
other places too?

Also, no luck yet on runtime PM. If the console is enabled omap won't
idle, and if no serial console is enabled, it just hangs. Will try
to debug this part further, it may be also related to the above.

Regards,

Tony

On 07/21/2014 11:35 AM, Tony Lindgren wrote:

> Looks like the following is needed to avoid the error, no idea why..
> But this is what we also do in omap-serial.c. It may be needed in
> other places too?

Yes, there was a third one on shutdown.

> Also, no luck yet on runtime PM. If the console is enabled omap won't
> idle, and if no serial console is enabled, it just hangs. Will try
> to debug this part further, it may be also related to the above.

My beaglebone xm won't do idle:

| omap3_pm_off_mode_enable: Core OFF disabled due to errata i583

but it would if it could, right? That means that I can't test the wake
via UART on this one?

So I will try to fix the tx-pm, fold patches and then prepare another
batch.
And I could verify that DMA works on that omap3 :)

> Regards,
> 
> Tony

Sebastian

* Sebastian Andrzej Siewior <bigeasy@linutronix.de> [140813 09:23]:
> On 07/21/2014 11:35 AM, Tony Lindgren wrote:
> 
> > Looks like the following is needed to avoid the error, no idea why..
> > But this is what we also do in omap-serial.c. It may be needed in
> > other places too?
> 
> Yes, there was a third one on shutdown.

OK
 
> > Also, no luck yet on runtime PM. If the console is enabled omap won't
> > idle, and if no serial console is enabled, it just hangs. Will try
> > to debug this part further, it may be also related to the above.
> 
> My beaglebone xm won't do idle:
> 
> | omap3_pm_off_mode_enable: Core OFF disabled due to errata i583
> 
> but it would if it could, right? That means that I can't test the wake
> via UART on this one?

Hmm OK yes that's disabled for some earlier ES revisions. I guess you
could comment out the limitations for PM_SDRC_WAKEUP_ERRATUM_i583
in both cpuidle34xx.c and pm34xx.c and see if off-idle is usable for
your tests :) It might be flakey but still usable for testing.
 
> So I will try to fix the tx-pm, fold patches and then prepare another
> batch.

OK great, let me know if you need more help.

> And I could verify that DMA works on that omap3 :)

OK

Regards,

Tony