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Subject[RFC PATCH 0/3] serial: uartps: Add run time support for more IPs than hardcoded 2
Date
Hi,

this series is trying to address discussion I had with Alan in past
https://patchwork.kernel.org/patch/9738445/.

It is moving uart_register_driver() to probe function like it is done in
pl011 driver.
And also introducing new function for alias compatibility checking to
resolve cases where some IPs have alias and some of them not.
This case is detected in pl011_probe_dt_alias() but not properly solved.

Also keep status of free ids/minor numbers in bitmap to know what's the
next unallocated number.

The same solution can be used in pl011, uart16550 and uartlite to really
get unified kernel.

Tested on these use cases:
Notes:
ff000000 is the first PS uart listed in dtsi
ff010000 is the second PS uart listed in dtsi

Standard zcu102 setting
serial0 = &uart0;
serial1 = &uart1;
[ 0.196628] ff000000.serial: ttyPS0 at MMIO 0xff000000 (irq = 33,
base_baud = 6250000) is a xuartps
[ 0.642542] ff010000.serial: ttyPS1 at MMIO 0xff010000 (irq = 34,
base_baud = 6250000) is a xuartps

Swapped zcu102 setting
serial0 = &uart1;
serial1 = &uart0;
[ 0.196472] ff000000.serial: ttyPS1 at MMIO 0xff000000 (irq = 33,
base_baud = 6250000) is a xuartps
[ 0.196824] ff010000.serial: ttyPS0 at MMIO 0xff010000 (irq = 34,
base_baud = 6250000) is a xuartps

uart0 on alias higher then MAX uart ports
serial0 = &uart1;
serial200 = &uart0;
[ 0.176793] ff000000.serial: ttyPS200 at MMIO 0xff000000 (irq = 33,
base_baud = 6250000) is a xuartps
[ 0.177288] ff010000.serial: ttyPS0 at MMIO 0xff010000 (irq = 34,
base_baud = 6250000) is a xuartps

Both uarts on higher aliases
serial1 = &uart1;
serial2 = &uart0;
[ 0.196470] ff000000.serial: ttyPS2 at MMIO 0xff000000 (irq = 33,
base_baud = 6250000) is a xuartps
[ 0.196823] ff010000.serial: ttyPS1 at MMIO 0xff010000 (irq = 34,
base_baud = 6250000) is a xuartps

uart0 not listed but it is probed first that's why should be ttyPS0 but
there is uart1 via alias
serial0 = &uart1;
[ 0.176656] xuartps ff000000.serial: No serial alias passed. Using
the first free id
[ 0.176671] xuartps ff000000.serial: Validate id 0
[ 0.176680] xuartps ff000000.serial: The empty id is 0
[ 0.176692] xuartps ff000000.serial: ID 0 already taken - skipped
[ 0.176701] xuartps ff000000.serial: Validate id 1
[ 0.176710] xuartps ff000000.serial: The empty id is 1
[ 0.176719] xuartps ff000000.serial: Selected ID 1 allocation passed
[ 0.176760] ff000000.serial: ttyPS1 at MMIO 0xff000000 (irq = 33,
base_baud = 6250000) is a xuartps
[ 0.177104] ff010000.serial: ttyPS0 at MMIO 0xff010000 (irq = 34,
base_baud = 6250000) is a xuartps

uart0 not listed but it is probed first that's why should be ttyPS0
serial1 = &uart1;
[ 0.176661] xuartps ff000000.serial: No serial alias passed. Using
the first free id
[ 0.176676] xuartps ff000000.serial: Validate id 0
[ 0.176686] xuartps ff000000.serial: The empty id is 0
[ 0.176696] xuartps ff000000.serial: Selected ID 0 allocation passed
[ 0.176737] ff000000.serial: ttyPS0 at MMIO 0xff000000 (irq = 33,
base_baud = 6250000) is a xuartps
[ 0.177069] ff010000.serial: ttyPS1 at MMIO 0xff010000 (irq = 34,
base_baud = 6250000) is a xuartps

uarts not listed in aliases list
[ 0.176673] xuartps ff000000.serial: No serial alias passed. Using
the first free id
[ 0.176687] xuartps ff000000.serial: Validate id 0
[ 0.176697] xuartps ff000000.serial: The empty id is 0
[ 0.176707] xuartps ff000000.serial: Selected ID 0 allocation passed
[ 0.176746] ff000000.serial: ttyPS0 at MMIO 0xff000000 (irq = 33,
base_baud = 6250000) is a xuartps
[ 0.177057] xuartps ff010000.serial: No serial alias passed. Using
the first free id
[ 0.177070] xuartps ff010000.serial: Validate id 0
[ 0.177079] xuartps ff010000.serial: The empty id is 0
[ 0.177089] xuartps ff010000.serial: Selected ID 0 allocation failed
[ 0.177098] xuartps ff010000.serial: Validate id 1
[ 0.177107] xuartps ff010000.serial: The empty id is 1
[ 0.177116] xuartps ff010000.serial: Selected ID 1 allocation passed
[ 0.177149] ff010000.serial: ttyPS1 at MMIO 0xff010000 (irq = 34,
base_baud = 6250000) is a xuartps

Thanks,
Michal


Michal Simek (3):
of: base: Introduce of_alias_check_id() to check alias IDs
serial: uartps: Move register to probe based on run time detection
serial: uartps: Change uart ports allocation

drivers/of/base.c | 49 +++++++++++
drivers/tty/serial/xilinx_uartps.c | 128 +++++++++++++++++++++++------
include/linux/of.h | 2 +
3 files changed, 153 insertions(+), 26 deletions(-)

--
2.17.0

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