On 03/01/2016 06:31 PM, Peter Hurley wrote: > On 02/29/2016 04:02 AM, Aleksey Makarov wrote: >> 'ARM Server Base Boot Requirements' [1] mentions SPCR (Serial Port >> Console Redirection Table) [2] as a mandatory ACPI table that >> specifies the configuration of serial console. >> >> Introduce a new function acpi_console_check(). At the uart port >> registration, this function checks if the ACPI SPCR table specifies >> its argument of type struct uart_port to be a console >> and if so calls add_preferred_console(). > > How will a user enable an earlycon on the same console as the SPCR > console if there is no DBG2 table?
... [ 0.000000] earlycon: pl11 at MMIO 0x0000000009000000 (options '') [ 0.000000] bootconsole [pl11] enabled ... [ 0.000000] Kernel command line: root=/dev/vda1 rw systemd.show_status=no acpi=force earlycon=pl011,0x9000000 ... [ 0.318248] ACPI: SPCR: adding preferred console [ttyAMA0] [ 0.318736] ARMH0011:00: ttyAMA0 at MMIO 0x9000000 (irq = 5, base_baud = 0) is a SBSA [ 0.319502] console [ttyAMA0] enabled [ 0.319502] console [ttyAMA0] enabled [ 0.319933] bootconsole [pl11] disabled [ 0.319933] bootconsole [pl11] disabled ... Why? > > >> Use SPCR to tell if SBSA serial driver should use 32-bit access to registers. >> >> Based on the work by Leif Lindholm [3] >> >> Should be applied to next-20160229. >> >> Tested on QEMU. SPCR support is included in QEMU's ARM mach-virt >> since 2.4 release. >> >> v4: >> - drop patch "ACPI: change __init to __ref for early_acpi_os_unmap_memory()" >> ACPI developers work on a new API and asked not to do that. >> Instead, use acpi_get_table_with_size()/early_acpi_os_unmap_memory() once >> and cache the result. (Lv Zheng) >> - fix some style issues (Yury Norov) >> >> v3: >> https://lkml.kernel.org/g/1455559532-8305-1-git-send-email-aleksey.maka...@linaro.org >> >> Greg Kroah-Hartman did not like v2 so I have rewritten this patchset: >> >> - drop acpi_match() member of struct console >> - drop implementations of this member for pl011 and 8250 >> - drop the patch that renames some vars in printk.c as it is not needed >> anymore >> - drop patch that introduces system wide acpi_table_parse2(). >> Instead introduce a custom acpi_table_parse_spcr() in spcr.c >> >> Instead of introducing a new match_acpi() member of struct console, >> this patchset introduces a new function acpi_console_check(). >> This function is called when a new uart is registered at serial_core.c >> the same way OF code checks for console. If the registered uart is the >> console specified by SPCR table, this function calls add_preferred_console() >> >> The restrictions of this approach are: >> >> - only serial consoles can be set up >> - only consoles specified by the memory/io address can be set up >> (SPCR can specify devices by PCI id/PCI address) >> >> v2: >> https://lkml.kernel.org/g/1455299022-11641-1-git-send-email-aleksey.maka...@linaro.org >> - don't use SPCR if user specified console in command line >> - fix initialization order of newcon->index = 0 >> - rename some variables at printk.c (Joe Perches, Peter Hurley) >> - enable ACPI_SPCR_TABLE in a separate patch (Andy Shevchenko) >> - remove the retry loop for console registering (Peter Hurley). >> Instead, obtain SPCR with acpi_get_table(). That works after >> call to acpi_early_init() i. e. in any *_initcall() >> - describe design decision behind introducing acpi_match() (Peter Hurley) >> - fix compilation for x86 + ACPI (Graeme Gregory) >> - introduce DBG2 constants in a separate patch (Andy Shevchenko) >> - fix a typo in DBG2 constants (Andy Shevchenko) >> - add ACPI_DBG2_ARM_SBSA_32BIT constant (Christopher Covington) >> - add support for ACPI_DBG2_ARM_SBSA_* consoles (Christopher Covington) >> - add documentation for functions >> - add a patch that uses SPCR to find if SBSA serial driver should use 32-bit >> accessor functions (Christopher Covington) >> - change __init to __ref for early_acpi_os_unmap_memory() in a separate patch >> - introduce acpi_table_parse2() in a separate patch >> - fix fetching the SPCR table early (Mark Salter) >> - add a patch from Mark Salter that introduces support for matching >> 8250-based >> consoles >> >> v1: >> https://lkml.kernel.org/g/1453722324-22407-1-git-send-email-aleksey.maka...@linaro.org >> >> [1] >> http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html >> [2] >> https://msdn.microsoft.com/en-us/library/windows/hardware/dn639132(v=vs.85).aspx >> [3] >> https://lkml.kernel.org/g/1441716217-23786-1-git-send-email-leif.lindh...@linaro.org >> >> Aleksey Makarov (4): >> ACPI: parse SPCR and enable matching console >> ACPI: enable ACPI_SPCR_TABLE on ARM64 >> ACPI: add definitions of DBG2 subtypes >> serial: pl011: use ACPI SPCR to setup 32-bit access >> >> arch/arm64/Kconfig | 1 + >> drivers/acpi/Kconfig | 3 + >> drivers/acpi/Makefile | 1 + >> drivers/acpi/spcr.c | 138 >> +++++++++++++++++++++++++++++++++++++++ >> drivers/tty/serial/amba-pl011.c | 2 + >> drivers/tty/serial/serial_core.c | 14 +++- >> include/acpi/actbl2.h | 5 ++ >> include/linux/acpi.h | 15 +++++ >> 8 files changed, 177 insertions(+), 2 deletions(-) >> create mode 100644 drivers/acpi/spcr.c >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
