Re: [PATCH] serial: uartlite: Move out-of-range port-numbers into ULITE_NR_UARTS range

Am 18.11.2021 um 09:34 schrieb Michal Simek:

On 11/17/21 23:15, Ruediger Willenberg wrote:

quoted

Find free uart_port struct in range 0 <= id < ULITE_NR_UARTS when
the device tree port-number property is outside that range. This
can happen because the Xilinx device tree generator does not start
enumerating Uartlites at 0 when there are PS-UARTs or AXI 16550A
UARTs in the system; it then enumerates all UARTs consecutively
despite them having separate drivers with separate structures.
This has become more problematic since the Kconfig property
SERIAL_UARTLITE_NR_UARTS enables precise allocation of uart_port
structs, which can't be used if the port-number doesn't start at 0

Signed-off-by: Ruediger Willenberg <redacted>
---
  drivers/tty/serial/uartlite.c | 8 ++++----
  1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
index d3d9566e5dbd..546eecdb6033 100644
--- a/drivers/tty/serial/uartlite.c
+++ b/drivers/tty/serial/uartlite.c

@@ -632,14 +632,14 @@ static int ulite_assign(struct device *dev, int id, u32 base, int irq,

      struct uart_port *port;
      int rc;
-    /* if id = -1; then scan for a free id and use that */
-    if (id < 0) {
+    /* if id -1 or out of range; then scan for a free id and use that */
+    if (id < 0 || id >= ULITE_NR_UARTS) {
          for (id = 0; id < ULITE_NR_UARTS; id++)
              if (ulite_ports[id].mapbase == 0)
                  break;
      }
-    if (id < 0 || id >= ULITE_NR_UARTS) {
-        dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
+    if (id == ULITE_NR_UARTS) {
+        dev_err(dev, "maximum number of %s assigned\n", ULITE_NAME);
          return -EINVAL;
      }

Don't you want to also inform user about it? They can expect that serial10 is going to be ttyUL10 
but if ULITE_NR_UARTS is less you will get different number and user will have no idea why.

Thanks,
Michal

Good catch, thanks! Will add a dev_notice() and repost.
-Ruediger