Re: [PATCH v2] serial: uartlite: Move out-of-range port-numbers into ULITE_NR_UARTS range
From: Michal Simek <hidden>
Date: 2021-11-19 12:22:02
On 11/18/21 22:17, Ruediger Willenberg wrote:
quoted hunk ↗ jump to hunk
Find free uart_port struct in range 0 <= id < ULITE_NR_UARTS when the device tree port-number property is outside that range. This happens when there are other UART types in the system because the Xilinx device tree generator numbers all UARTs consecutively; as a result, not as many Uartlites as specified by the SERIAL_UARTLITE_NR_UARTS parameter could be successfully added. Signed-off-by: Ruediger Willenberg <redacted> --- Changes in v2: - give KERN_NOTICE when changing the id, with reference to the requested port-number drivers/tty/serial/uartlite.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c index d3d9566e5dbd..27c513c7350e 100644 --- a/drivers/tty/serial/uartlite.c +++ b/drivers/tty/serial/uartlite.c@@ -631,15 +631,17 @@ static int ulite_assign(struct device *dev, int id, u32 base, int irq, { struct uart_port *port; int rc; + int oor_id = -1; - /* 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) { + oor_id = id; 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; }@@ -676,7 +678,11 @@ static int ulite_assign(struct device *dev, int id, u32 base, int irq, dev_set_drvdata(dev, NULL); return rc; }
nit: please keep this newline here.
- + if (oor_id >= 0) + dev_notice(dev, + "assigned uartlite with device tree port-number=<%i> to %s%i\n", + oor_id, ULITE_NAME, id); +
[linux](master)$ ./scripts/checkpatch.pl --strict 0001-serial-uartlite-Move-out-of-range-port-numbers-into-.patch CHECK: Alignment should match open parenthesis #54: FILE: drivers/tty/serial/uartlite.c:669: + dev_notice(dev, + "assigned uartlite with device tree port-number=<%i> to %s%i\n",
return 0; }
And there is one more issue with this. If you start to mix serial IPs
which are partially recorded in aliases. For example like this.
aliases {
serial0 = &uart1;
};
uart0 {
...
};
uart1 {
...
};
Uart0 is probed first. It is without alias and id 0 will be assigned to
it. Then uart1 is probed. It looks at aliases you get id 0 but it is
already taken and you end up with "cannot assign to %s%i; it is already
in use"
It would be IMHO better to use of_alias_get_highest_id().
In xilinx_uartps I used in past of_alias_get_alias_list() to get
bitfield of aliases which are taken and use only that one which are free
but up2you. Having the same behavior across drivers would be good.
Thanks,
Michal