This is the third revision of the SBSA UART support series. It is based on tty-next plus Dave's latest PL011 work[2], which fixes all problems seen on the fast models and on some hardware. Compared to v2 building as a module has been fixed. ---- 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. As changing the baudrate and other communication parameters is not specified for the SBSA UART, any userland attempt will be denied by the kernel. The device-tree provided fixed baud rate will be reported, so stty for instance prints the right value. 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/v3), which has all patches 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. According to Russell this is still racy, but still better than the current solution. 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 and the baud rate with the "current-speed" property. Of course testing with a real SBSA Generic UART is welcomed - as well as regression testing with any PL011 implementation. Changelog: v2 .. v3: - rebased on top of tty-next and Dave's latest PL011 rework[2] - fixed module build - removed redundant =NULL members in sbsa_uart_ops v1 .. v2: - rebased on top of 4.0-rc1 and Dave's newest PL011 fix [4] - added mandatory current-speed property and report that to userland 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-April/334975.html [3] http://www.linux-arm.org/git?p=linux-ap.git git://linux-arm.org/linux-ap.git [4] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/327631.html =========================================== 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 | 10 + drivers/tty/serial/amba-pl011.c | 529 ++++++++++++++------ 2 files changed, 398 insertions(+), 141 deletions(-) create mode 100644 Documentation/devicetree/bindings/serial/arm_sbsa_uart.txt -- 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