| Message ID | 1230037894-26837-1-git-send-email-jacmet@sunsite.dk (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
Peter Korsgaard wrote: > - It doesn't respect console= and still outputs console messages even > if console isn't ttySx (E.G. if CONFIG_SILENT_CONSOLE is enabled in > U-Boot which sets 'console=' I believe it uses /chosen/linux,stdout-path; u-boot could clear that if silent console is desired. > As that isn't always desirable, add a PPC_UDBG_16550_CONSOLE kconfig > symbol to let the user disable it (only visible if CONFIG_EMBEDDED). There's an existing CONFIG_PPC_EARLY_DEBUG that it could depend on instead. -Scott
On Tue, 2008-12-23 at 14:11 +0100, Peter Korsgaard wrote: > The udbg console is currently always enabled for platforms selecting > the PPC_UDBG_16550 symbol (needed to create platform devices for > 8250 SoC UARTs from DT). > > Now, the udbg console is nice for debugging as it works so early, but > it also has a number of disadvantages: .../... I don't think that's the right approach. I think a better one is to make a config option that selects whether the udbg console is registered. ie. CONFIG_UDBG_CONSOLE which would affect the calls sites in setup_32/64.c or the register_udbg_console() function itself in udbg.c Ben.
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index 92673b4..4651c0b 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -80,7 +80,8 @@ obj-$(CONFIG_MODULES) += ppc_ksyms.o obj-$(CONFIG_BOOTX_TEXT) += btext.o obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_KPROBES) += kprobes.o -obj-$(CONFIG_PPC_UDBG_16550) += legacy_serial.o udbg_16550.o +obj-$(CONFIG_PPC_UDBG_16550) += legacy_serial.o +obj-$(CONFIG_PPC_UDBG_16550_CONSOLE) += udbg_16550.o obj-$(CONFIG_STACKTRACE) += stacktrace.o pci64-$(CONFIG_PPC64) += pci_dn.o isa-bridge.o diff --git a/arch/powerpc/kernel/legacy_serial.c b/arch/powerpc/kernel/legacy_serial.c index 9ddfaef..c0e9866 100644 --- a/arch/powerpc/kernel/legacy_serial.c +++ b/arch/powerpc/kernel/legacy_serial.c @@ -279,6 +279,7 @@ static int __init add_legacy_pci_port(struct device_node *np, } #endif +#ifdef CONFIG_PPC_UDBG_16550_CONSOLE static void __init setup_legacy_serial_console(int console) { struct legacy_serial_info *info = @@ -295,6 +296,9 @@ static void __init setup_legacy_serial_console(int console) DBG("default console speed = %d\n", info->speed); udbg_init_uart(addr, info->speed, info->clock); } +#else +#define setup_legacy_serial_console(console) do { } while (0) +#endif /* * This is called very early, as part of setup_system() or eventually diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig index 47e956c..bc3ce47 100644 --- a/arch/powerpc/platforms/Kconfig +++ b/arch/powerpc/platforms/Kconfig @@ -312,4 +312,11 @@ config MPC8xxx_GPIO Say Y here if you're going to use hardware that connects to the MPC831x/834x/837x/8572/8610 GPIOs. +config PPC_UDBG_16550_CONSOLE + bool "Boot console on 16550 UDBG" if EMBEDDED + depends on PPC_UDBG_16550 + default y + help + Say Y here to use the UDBG infrastructure for early boot messages. + endmenu
The udbg console is currently always enabled for platforms selecting the PPC_UDBG_16550 symbol (needed to create platform devices for 8250 SoC UARTs from DT). Now, the udbg console is nice for debugging as it works so early, but it also has a number of disadvantages: - It doesn't respect console= and still outputs console messages even if console isn't ttySx (E.G. if CONFIG_SILENT_CONSOLE is enabled in U-Boot which sets 'console=' - It's slow (boot is ~0.3s slower on my mpc8347 platform compared to using the 8250 driver right away) - It slightly bloats the kernel (pretty insignificant, around 1K) As that isn't always desirable, add a PPC_UDBG_16550_CONSOLE kconfig symbol to let the user disable it (only visible if CONFIG_EMBEDDED). Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk> --- arch/powerpc/kernel/Makefile | 3 ++- arch/powerpc/kernel/legacy_serial.c | 4 ++++ arch/powerpc/platforms/Kconfig | 7 +++++++ 3 files changed, 13 insertions(+), 1 deletions(-)