serdev: Don't claim unsupported ACPI serial devices

commit c5ee0b3104e0b292d353e63fd31cb8c692645d8c upstream.

Serdev sub-system claims all ACPI serial devices that are not already
initialised. As a result, no device node is created for serial ports
on certain boards such as the Apollo Lake based UP2. This has the
unintended consequence of not being able to raise the login prompt via
serial connection.

Introduce a blacklist to reject ACPI serial devices that should not be
claimed by serdev sub-system. Add the peripheral ids for Intel HS UART
to the blacklist to bring back serial port on SoCs carrying them.

Cc: stable@vger.kernel.org
Signed-off-by: Punit Agrawal <punit1.agrawal@toshiba.co.jp>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Johan Hovold <johan@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20191219100345.911093-1-punit1.agrawal@toshiba.co.jp
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index 9db93f500b4e722cfa5df55201f28238d484b9ae..c66a04d24f1d3c543b67683124f3df0000318996 100644 (file)
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -526,6 +526,12 @@ static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl,
        return AE_OK;
 }
 
+static const struct acpi_device_id serdev_acpi_devices_blacklist[] = {
+       { "INT3511", 0 },
+       { "INT3512", 0 },
+       { },
+};
+
 static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
                                       void *data, void **return_value)
 {
@@ -535,6 +541,10 @@ static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
        if (acpi_bus_get_device(handle, &adev))
                return AE_OK;
 
+       /* Skip if black listed */
+       if (!acpi_match_device_ids(adev, serdev_acpi_devices_blacklist))
+               return AE_OK;
+
        return acpi_serdev_register_device(ctrl, adev);
 }