On 21 May 2015 18:19:18 BST, Mark Langsdorf <mlangsdo@xxxxxxxxxx> wrote: >On 05/21/2015 11:26 AM, Andre Przywara wrote: >> This is the fifth revision of the SBSA UART support series, based on >> the current tty-next branch. >> Beside some minor formatting issues fixed (thanks ot Jakub for >> noticing) the SBSA UART set_termios() function has been reworked. >> We now completely ignore the old value, instead we filter the new >> setting to match the SBSA UART's fixed parameters for word size, >> parity, stop bits and so on. >> This should also address the issues people have seen with ACPI on >> Fedora systems. >> Mark, Naresh, Graeme: can you confirm that this version works for >> you? If needed I can bake a follow-up patch on top of v4. >> ---- > >Works for me, thanks. > >Tested-by: Mark Langsdorf <mlangsdo@xxxxxxxxxx> > >--Mark Langsdorf > I am on holiday so can't retest but Mark is using same setup as me so please proceed Graeme >> The ARM Server Base System Architecture[1] document describes a >> generic UART which is a subset of the ARM 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 and an ACPI binding. >> 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 is based on Greg's tty-next branch, a git repo can >> be found at [2] (branch sbsa-uart/v5). >> >> Patch 1/11 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. >> Patch 11 adds the necessary ACPI boilerplate. >> >> 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. >> I tested this on a FastModel, a Juno and a Midway machine, both in >> PL011 and in (DT-emulated) SBSA mode. >> >> Tested-by: Robert Richter <rrichter@xxxxxxxxxx> >> Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> >> Tested-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx> >> >> Changelog: >> v4 .. v5: >> - fixed checkpatch --strict complaints >> - rework set_termios: >> - disallow changes or UART fixed communication parameters >> - ignore old value to fix an issue with Fedora on ACPI >> >> v3 .. v4: >> - fixed rebase artifact >> - moved memory allocation out of pl011_allocate_port() function >> (and consequently renamed that to pl011_find_free_port) >> - added ACPI driver binding >> >> v2 .. v3: >> - rebased on top of tty-next and Dave's latest PL011 rework >> - 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 [3] >> - 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://www.linux-arm.org/git?p=linux-ap.git >> git://linux-arm.org/linux-ap.git >> [3] >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 >> >> Graeme Gregory (1): >> drivers: PL011: add ACPI probing for SBSA UART >> >> .../devicetree/bindings/serial/arm_sbsa_uart.txt | 10 + >> drivers/tty/serial/amba-pl011.c | 550 >+++++++++++++++------ >> 2 files changed, 412 insertions(+), 148 deletions(-) >> create mode 100644 >Documentation/devicetree/bindings/serial/arm_sbsa_uart.txt >> -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -- 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
