On 4 January 2016 at 23:13, Timur Tabi [off-list ref] wrote:

On Wed, Dec 23, 2015 at 8:19 AM, Aleksey Makarov
[off-list ref] wrote:

quoted

From: Graeme Gregory <redacted>

In ACPI this device is only defined in SBSA mode so
if we are coming from ACPI use this mode.

Signed-off-by: Graeme Gregory <redacted>
Signed-off-by: Aleksey Makarov <redacted>
---
 drivers/tty/serial/amba-pl011.c | 37 ++++++++++++++++++++++++++-----------
 1 file changed, 26 insertions(+), 11 deletions(-)

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 899a771..974cb9e 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c

@@ -2368,18 +2368,33 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
        if (!uap)
                return -ENOMEM;

-       uap->clk = devm_clk_get(&dev->dev, NULL);
-       if (IS_ERR(uap->clk))
-               return PTR_ERR(uap->clk);
-
-       uap->vendor = vendor;
-       uap->lcrh_rx = vendor->lcrh_rx;
-       uap->lcrh_tx = vendor->lcrh_tx;
-       uap->fifosize = vendor->get_fifosize(dev);
-       uap->port.irq = dev->irq[0];
-       uap->port.ops = &amba_pl011_pops;
+       /* ACPI only defines SBSA variant */
+       if (has_acpi_companion(&dev->dev)) {
+               /*
+                * According to ARM ARMH0011 is currently the only mapping
+                * of pl011 in ACPI and it's mapped to SBSA UART mode
+                */
+               uap->vendor     = &vendor_sbsa;
+               uap->fifosize   = 32;
+               uap->port.ops   = &sbsa_uart_pops;
+               uap->fixed_baud = 115200;

I'm confused by this patch.  We already have code like this in
tty-next, in the form of sbsa_uart_probe():

https://kernel.googlesource.com/pub/scm/linux/kernel/git/gregkh/tty/+/tty-next/drivers/tty/serial/amba-pl011.c#2553

Because Russell expressed unhappiness at that code existing. So this
is an alternative method to do same thing with ACPI.

If the "arm,sbsa-uart" id was added to drivers/of/platform.c as an
AMBA id then the same could be done for DT as well.

Ultimately this patch is optional depending on maintainers opinion!

Graeme