Hi, this is my first try on a driver for the generic UART defined in the ARM Server Base System Architecture (SBSA) [1] document. It it basically a severly restricted subset of the PL011 driver, removing DMA, modem control, baud rate setting and other features. The idea of it is to let it be initialized by the firmware, so Linux can just use it without fiddling with the parameters. Given the subset nature of the spec, a full featured PL011 can be driven by this driver - given it has been initialized before. So this version is a stripped copy of the AMBA PL011 driver, removing everything not needed (including the AMBA bindings, instead just use the device tree). This works for me on a hardware PL011 and on the fast model. My version of it allows to restrict the register set to the SBSA subset. I tried deriving it from the goldfish TTY driver before, but that didn't work very well - it had no TX IRQ support and required an ugly hack to convert the line endings on the console. To avoid further churn with the device namings, this driver also uses the ttyAMA prefix. That seems to make sense given the relationship of the two devices and the possibility to drive real PL011s with this driver. However there is an issue when both drivers are active: the numbering could possibly be wrong, causing udev to complain. So there is the possibility to fold this driver back into amba-pl011.c, providing a separate _probe function and a separate struct uart_ops, possibly reusing PL011 functions, while using extra functions for the incompatible part of it. Not sure if it's worth it, though. I'd love to have some feedback on how to proceed from here: Is this separate driver (file) OK? Should this be part of the PL011 driver? Should it use a different tty prefix? Does it need the separate config options? Should the existing PL011 driver be refactored to support both? Cheers, Andre P.S. There is an almost trivial patch to add ACPI support for this, but which this margin is too narrow to contain ;-) [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0029 Andre Przywara (1): drivers: introduce ARM SBSA generic UART driver .../devicetree/bindings/serial/arm_sbsa_uart.txt | 6 + drivers/tty/serial/Kconfig | 28 + drivers/tty/serial/Makefile | 1 + drivers/tty/serial/sbsa_uart.c | 793 ++++++++++++++++++++ include/uapi/linux/serial_core.h | 1 + 5 files changed, 829 insertions(+) create mode 100644 Documentation/devicetree/bindings/serial/arm_sbsa_uart.txt create mode 100644 drivers/tty/serial/sbsa_uart.c -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
