Re: [PATCH v2 1/2] acpi, spcr: Make SPCR avialable to other architectures

Lorenzo Pieralisi
2017-12-14T10:30:36Z

On Wed, Dec 13, 2017 at 03:11:33PM -0600, Timur Tabi wrote:
> On 12/13/2017 06:45 AM, Lorenzo Pieralisi wrote:
> >>+/*
> >>+ * Erratum 44 for QDF2432v1 and QDF2400v1 SoCs describes the BUSY bit as
> >>+ * occasionally getting stuck as 1. To avoid the potential for a hang, check
> >>+ * TXFE == 0 instead of BUSY == 1. This may not be suitable for all UART
> >>+ * implementations, so only do so if an affected platform is detected in
> >>+ * acpi_parse_spcr().
> >>+ */
> >>+bool qdf2400_e44_present;
> >>+EXPORT_SYMBOL(qdf2400_e44_present);
> >
> >My eyes, this is horrible but it is not introduced by this patch. It
> >would have been much better if:
> >
> >drivers/tty/serial/amba-pl011.c
> >
> >parsed the SPCR table (again) to detect it instead of relying on this
> >horrible exported flag.
>
> I didn't want to put any ACPI code in amba-pl011.c, so putting it in spcr.c
> made the most sense. I agree the global variable is ugly. If you have a
> better idea, I'm all ears.

I told you my idea. It could have been made easier by reusing the
ACPI_DECLARE_PROBE_ENTRY() mechanism.

> If it's any consolation, this erratum affects only 1.x silicon, which is
> technically pre-production (although a lot of people have them). This
> work-around will eventually be reverted.

The sooner the better.

Lorenzo