On Fri, Jan 16, 2015 at 05:22:56PM +0000, Andre Przywara wrote: > The ARM Server Base System Architecture[1] document describes a > generic UART which is a subset of the PL011 UART. > It lacks DMA support, baud rate control and modem status line > control, among other things. > The idea is to move the UART initialization and setup into the > firmware (which does this job today already) and let the kernel just > use the UART for sending and receiving characters. > > This patchset integrates support for this UART subset into the > existing PL011 driver - basically by refactoring some > functions and providing a new uart_ops structure for it. It also has > a separate probe function to be not dependent on AMBA/PrimeCell. > It provides a device tree binding, but can easily be adapted to other > device configuration systems. > Beside the obvious effect of code sharing reusing most of the PL011 > code has the advantage of not introducing another serial device > prefix, so it can go with ttyAMA, which seems to be pretty common. > > This series relies on Dave's recent PL011 fix[2], which gets rid of > the loopback trick to get the UART going. There is a repo at [3] > (branch sbsa-uart/v1), which has this patch already integrated. > > Patch 1/10 contains a bug fix which applies to the PL011 part also, > it should be considered regardless of the rest of the series. > Patch 2-7 refactor some PL011 functions by splitting them up into > smaller pieces, so that most of the code can be reused later by the > SBSA part. > Patch 8 and 9 introduce two new properties for the vendor structure, > this is for SBSA functionality which cannot be controlled by > separate uart_ops members only. > Patch 10 then finally drops in the SBSA specific code, by providing > a new uart_ops, vendor struct and probe function for it. Also the new > device tree binding is documented. > > For testing you should be able to take any hardware which has a PL011 > and change the DT to use a "arm,sbsa-uart" compatible string. > Of course testing with a real SBSA Generic UART is welcomed! > I have tested this series on Juno where it seems to work and also on FVP model where there are some issues. On the FVP when we enter usespace a couple of 32 character strings are printed then nothing else. 32 Characters is a suspicious number. This occurs with both OE based FS from linaro and debian ubstable FS. My FVP is version 5602 Graeme > Cheers, > Andre > > [1] ARM-DEN-0029 Server Base System Architecture, available (click- > thru...) from http://infocenter.arm.com > [2] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-January/315248.html > [3] http://www.linux-arm.org/git?p=linux-ap.git > git://linux-arm.org/linux-ap.git > > Andre Przywara (10): > drivers: PL011: avoid potential unregister_driver call > drivers: PL011: refactor pl011_startup() > drivers: PL011: refactor pl011_shutdown() > drivers: PL011: refactor pl011_set_termios() > drivers: PL011: refactor pl011_probe() > drivers: PL011: replace UART_MIS reading with _RIS & _IMSC > drivers: PL011: move cts_event workaround into separate function > drivers: PL011: allow avoiding UART enabling/disabling > drivers: PL011: allow to supply fixed option string > drivers: PL011: add support for the ARM SBSA generic UART > > .../devicetree/bindings/serial/arm_sbsa_uart.txt | 9 + > drivers/tty/serial/amba-pl011.c | 510 ++++++++++++++------ > 2 files changed, 381 insertions(+), 138 deletions(-) > create mode 100644 Documentation/devicetree/bindings/serial/arm_sbsa_uart.txt > > -- > 1.7.9.5 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- 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
