| Message ID | 20200227152156.87385-3-andriy.shevchenko@linux.intel.com |
|---|---|
| State | Accepted |
| Commit | 98036fbdaf0ac1d6dc3ab3cb6db24c020bb65d6f |
| Headers | show |
| Series | [v1,1/3] dm: serial: Add clock member to struct serial_device_info | expand |
On Thu, Feb 27, 2020 at 11:22 PM Andy Shevchenko <andriy.shevchenko at linux.intel.com> wrote: > > SPCR has no clue if the UART base clock speed is different to > the default one. However, the SPCR 1.04 defines baud rate 0 as > a preconfigured state of UART and OS is supposed not to touch > the configuration of the serial device. > > Linux kernel supports that starting from v5.0, see commit > b413b1abeb21 ("ACPI: SPCR: Consider baud rate 0 as preconfigured state") > for the details. > > Signed-off-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com> > --- > arch/x86/lib/acpi_table.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
On Wed, Apr 15, 2020 at 10:20 PM Bin Meng <bmeng.cn at gmail.com> wrote: > > On Thu, Feb 27, 2020 at 11:22 PM Andy Shevchenko > <andriy.shevchenko at linux.intel.com> wrote: > > > > SPCR has no clue if the UART base clock speed is different to > > the default one. However, the SPCR 1.04 defines baud rate 0 as > > a preconfigured state of UART and OS is supposed not to touch > > the configuration of the serial device. > > > > Linux kernel supports that starting from v5.0, see commit > > b413b1abeb21 ("ACPI: SPCR: Consider baud rate 0 as preconfigured state") > > for the details. > > > > Signed-off-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com> > > --- > > arch/x86/lib/acpi_table.c | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > > > Reviewed-by: Bin Meng <bmeng.cn at gmail.com> applied to u-boot-x86, thanks!
diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c index 66e32f21bd..074987e294 100644 --- a/arch/x86/lib/acpi_table.c +++ b/arch/x86/lib/acpi_table.c @@ -471,6 +471,15 @@ static void acpi_create_spcr(struct acpi_spcr *spcr) spcr->pci_device_id = 0xffff; spcr->pci_vendor_id = 0xffff; + /* + * SPCR has no clue if the UART base clock speed is different + * to the default one. However, the SPCR 1.04 defines baud rate + * 0 as a preconfigured state of UART and OS is supposed not + * to touch the configuration of the serial device. + */ + if (serial_info.clock != SERIAL_DEFAULT_CLOCK) + spcr->baud_rate = 0; + /* Fix checksum */ header->checksum = table_compute_checksum((void *)spcr, header->length); }
SPCR has no clue if the UART base clock speed is different to the default one. However, the SPCR 1.04 defines baud rate 0 as a preconfigured state of UART and OS is supposed not to touch the configuration of the serial device. Linux kernel supports that starting from v5.0, see commit b413b1abeb21 ("ACPI: SPCR: Consider baud rate 0 as preconfigured state") for the details. Signed-off-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com> --- arch/x86/lib/acpi_table.c | 9 +++++++++ 1 file changed, 9 insertions(+)