| Message ID | 20220819211254.22192-1-pali@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | powerpc: Add support for early debugging via Serial 16550 console | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/github-powerpc_selftests | success | Successfully ran 10 jobs. |
| snowpatch_ozlabs/github-powerpc_ppctests | success | Successfully ran 10 jobs. |
| snowpatch_ozlabs/github-powerpc_clang | success | Successfully ran 6 jobs. |
| snowpatch_ozlabs/github-powerpc_sparse | success | Successfully ran 4 jobs. |
| snowpatch_ozlabs/github-powerpc_kernel_qemu | success | Successfully ran 23 jobs. |
Hi-- On 8/19/22 14:12, Pali Rohár wrote: > Currently powerpc early debugging contains lot of platform specific > options, but does not support standard UART / serial 16550 console. > > Later legacy_serial.c code supports registering UART as early debug console > from device tree but it is not early during booting, but rather later after > machine description code finishes. > > So for real early debugging via UART is current code unsuitable. > > Add support for new early debugging option CONFIG_PPC_EARLY_DEBUG_16550 > which enable Serial 16550 console on address defined by new option > CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR and by stride by option > CONFIG_PPC_EARLY_DEBUG_16550_STRIDE. > > With this change it is possible to debug powerpc machine descriptor code. > For example this early debugging code can print on serial console also > "No suitable machine description found" error which is done before > legacy_serial.c code. > > Signed-off-by: Pali Rohár <pali@kernel.org> > --- > Tested on P2020 board. It allowed me do debug and implement this patch series: > https://lore.kernel.org/linuxppc-dev/20220819191557.28116-1-pali@kernel.org/ > --- > arch/powerpc/Kconfig.debug | 14 ++++++++++++++ > arch/powerpc/include/asm/udbg.h | 1 + > arch/powerpc/kernel/udbg.c | 2 ++ > arch/powerpc/kernel/udbg_16550.c | 33 ++++++++++++++++++++++++++++++++ > 4 files changed, 50 insertions(+) > > diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug > index 9f363c143d86..a4e7d90a45d2 100644 > --- a/arch/powerpc/Kconfig.debug > +++ b/arch/powerpc/Kconfig.debug > @@ -276,6 +276,11 @@ config PPC_EARLY_DEBUG_OPAL_HVSI > Select this to enable early debugging for the PowerNV platform > using an "hvsi" console > > +config PPC_EARLY_DEBUG_16550 > + bool "Serial 16550" > + help > + Select this to enable early debugging via Serial 16550 console > + > config PPC_EARLY_DEBUG_MEMCONS > bool "In memory console" > help > @@ -355,6 +360,15 @@ config PPC_EARLY_DEBUG_CPM_ADDR > platform probing is done, all platforms selected must > share the same address. > > +config PPC_EARLY_DEBUG_16550_PHYSADDR > + hex "Early debug Serial 16550 physical address" > + depends on PPC_EARLY_DEBUG_16550 Is there any chance that you could provide a default value here so that 'make olddefconfig' does not end up like it does without having a default value? CONFIG_PPC_EARLY_DEBUG_16550=y # CONFIG_PPC_EARLY_DEBUG_MEMCONS is not set CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR= CONFIG_PPC_EARLY_DEBUG_16550_STRIDE=1 which then causes a kconfig prompt when starting the build... > + > +config PPC_EARLY_DEBUG_16550_STRIDE > + int "Early debug Serial 16550 stride" > + depends on PPC_EARLY_DEBUG_16550 > + default 1 > + > config FAIL_IOMMU > bool "Fault-injection capability for IOMMU" > depends on FAULT_INJECTION Thanks.
On Friday 19 August 2022 15:34:14 Randy Dunlap wrote: > Hi-- > > On 8/19/22 14:12, Pali Rohár wrote: > > Currently powerpc early debugging contains lot of platform specific > > options, but does not support standard UART / serial 16550 console. > > > > Later legacy_serial.c code supports registering UART as early debug console > > from device tree but it is not early during booting, but rather later after > > machine description code finishes. > > > > So for real early debugging via UART is current code unsuitable. > > > > Add support for new early debugging option CONFIG_PPC_EARLY_DEBUG_16550 > > which enable Serial 16550 console on address defined by new option > > CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR and by stride by option > > CONFIG_PPC_EARLY_DEBUG_16550_STRIDE. > > > > With this change it is possible to debug powerpc machine descriptor code. > > For example this early debugging code can print on serial console also > > "No suitable machine description found" error which is done before > > legacy_serial.c code. > > > > Signed-off-by: Pali Rohár <pali@kernel.org> > > --- > > Tested on P2020 board. It allowed me do debug and implement this patch series: > > https://lore.kernel.org/linuxppc-dev/20220819191557.28116-1-pali@kernel.org/ > > --- > > arch/powerpc/Kconfig.debug | 14 ++++++++++++++ > > arch/powerpc/include/asm/udbg.h | 1 + > > arch/powerpc/kernel/udbg.c | 2 ++ > > arch/powerpc/kernel/udbg_16550.c | 33 ++++++++++++++++++++++++++++++++ > > 4 files changed, 50 insertions(+) > > > > diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug > > index 9f363c143d86..a4e7d90a45d2 100644 > > --- a/arch/powerpc/Kconfig.debug > > +++ b/arch/powerpc/Kconfig.debug > > @@ -276,6 +276,11 @@ config PPC_EARLY_DEBUG_OPAL_HVSI > > Select this to enable early debugging for the PowerNV platform > > using an "hvsi" console > > > > +config PPC_EARLY_DEBUG_16550 > > + bool "Serial 16550" > > + help > > + Select this to enable early debugging via Serial 16550 console > > + > > config PPC_EARLY_DEBUG_MEMCONS > > bool "In memory console" > > help > > @@ -355,6 +360,15 @@ config PPC_EARLY_DEBUG_CPM_ADDR > > platform probing is done, all platforms selected must > > share the same address. > > > > +config PPC_EARLY_DEBUG_16550_PHYSADDR > > + hex "Early debug Serial 16550 physical address" > > + depends on PPC_EARLY_DEBUG_16550 > > Is there any chance that you could provide a default value here > so that 'make olddefconfig' does not end up like it does > without having a default value? No. Because there is not any default value. Physical address of 16550 is hardly HW dependent. Possibly also bootloader dependent (if it can remap peripherals to different physical addresses). User _has to_ specify correct physical address if want to use early debug 16550 console. > CONFIG_PPC_EARLY_DEBUG_16550=y > # CONFIG_PPC_EARLY_DEBUG_MEMCONS is not set > CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR= > CONFIG_PPC_EARLY_DEBUG_16550_STRIDE=1 > > which then causes a kconfig prompt when starting > the build... Cannot we set somehow that PPC_EARLY_DEBUG_16550 would be disabled by default when upgrading defconfig? > > + > > +config PPC_EARLY_DEBUG_16550_STRIDE > > + int "Early debug Serial 16550 stride" > > + depends on PPC_EARLY_DEBUG_16550 > > + default 1 > > + > > config FAIL_IOMMU > > bool "Fault-injection capability for IOMMU" > > depends on FAULT_INJECTION > > Thanks. > -- > ~Randy
On 8/19/22 15:38, Pali Rohár wrote: > On Friday 19 August 2022 15:34:14 Randy Dunlap wrote: >> Hi-- >> >> On 8/19/22 14:12, Pali Rohár wrote: >>> Currently powerpc early debugging contains lot of platform specific >>> options, but does not support standard UART / serial 16550 console. >>> >>> Later legacy_serial.c code supports registering UART as early debug console >>> from device tree but it is not early during booting, but rather later after >>> machine description code finishes. >>> >>> So for real early debugging via UART is current code unsuitable. >>> >>> Add support for new early debugging option CONFIG_PPC_EARLY_DEBUG_16550 >>> which enable Serial 16550 console on address defined by new option >>> CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR and by stride by option >>> CONFIG_PPC_EARLY_DEBUG_16550_STRIDE. >>> >>> With this change it is possible to debug powerpc machine descriptor code. >>> For example this early debugging code can print on serial console also >>> "No suitable machine description found" error which is done before >>> legacy_serial.c code. >>> >>> Signed-off-by: Pali Rohár <pali@kernel.org> >>> --- >>> Tested on P2020 board. It allowed me do debug and implement this patch series: >>> https://lore.kernel.org/linuxppc-dev/20220819191557.28116-1-pali@kernel.org/ >>> --- >>> arch/powerpc/Kconfig.debug | 14 ++++++++++++++ >>> arch/powerpc/include/asm/udbg.h | 1 + >>> arch/powerpc/kernel/udbg.c | 2 ++ >>> arch/powerpc/kernel/udbg_16550.c | 33 ++++++++++++++++++++++++++++++++ >>> 4 files changed, 50 insertions(+) >>> >>> diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug >>> index 9f363c143d86..a4e7d90a45d2 100644 >>> --- a/arch/powerpc/Kconfig.debug >>> +++ b/arch/powerpc/Kconfig.debug >>> @@ -276,6 +276,11 @@ config PPC_EARLY_DEBUG_OPAL_HVSI >>> Select this to enable early debugging for the PowerNV platform >>> using an "hvsi" console >>> >>> +config PPC_EARLY_DEBUG_16550 >>> + bool "Serial 16550" >>> + help >>> + Select this to enable early debugging via Serial 16550 console >>> + >>> config PPC_EARLY_DEBUG_MEMCONS >>> bool "In memory console" >>> help >>> @@ -355,6 +360,15 @@ config PPC_EARLY_DEBUG_CPM_ADDR >>> platform probing is done, all platforms selected must >>> share the same address. >>> >>> +config PPC_EARLY_DEBUG_16550_PHYSADDR >>> + hex "Early debug Serial 16550 physical address" >>> + depends on PPC_EARLY_DEBUG_16550 >> >> Is there any chance that you could provide a default value here >> so that 'make olddefconfig' does not end up like it does >> without having a default value? > > No. Because there is not any default value. Physical address of 16550 is > hardly HW dependent. Possibly also bootloader dependent (if it can remap > peripherals to different physical addresses). > > User _has to_ specify correct physical address if want to use early > debug 16550 console. OK, we'll see if it ever causes a real problem then... >> CONFIG_PPC_EARLY_DEBUG_16550=y >> # CONFIG_PPC_EARLY_DEBUG_MEMCONS is not set >> CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR= >> CONFIG_PPC_EARLY_DEBUG_16550_STRIDE=1 >> >> which then causes a kconfig prompt when starting >> the build... > > Cannot we set somehow that PPC_EARLY_DEBUG_16550 would be disabled by > default when upgrading defconfig? Don't know about that. Thanks.
Le 20/08/2022 à 00:34, Randy Dunlap a écrit : > Hi-- > > On 8/19/22 14:12, Pali Rohár wrote: >> Currently powerpc early debugging contains lot of platform specific >> options, but does not support standard UART / serial 16550 console. >> >> Later legacy_serial.c code supports registering UART as early debug console >> from device tree but it is not early during booting, but rather later after >> machine description code finishes. >> >> So for real early debugging via UART is current code unsuitable. >> >> Add support for new early debugging option CONFIG_PPC_EARLY_DEBUG_16550 >> which enable Serial 16550 console on address defined by new option >> CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR and by stride by option >> CONFIG_PPC_EARLY_DEBUG_16550_STRIDE. >> >> With this change it is possible to debug powerpc machine descriptor code. >> For example this early debugging code can print on serial console also >> "No suitable machine description found" error which is done before >> legacy_serial.c code. >> >> Signed-off-by: Pali Rohár <pali@kernel.org> >> --- >> Tested on P2020 board. It allowed me do debug and implement this patch series: >> https://lore.kernel.org/linuxppc-dev/20220819191557.28116-1-pali@kernel.org/ >> --- >> arch/powerpc/Kconfig.debug | 14 ++++++++++++++ >> arch/powerpc/include/asm/udbg.h | 1 + >> arch/powerpc/kernel/udbg.c | 2 ++ >> arch/powerpc/kernel/udbg_16550.c | 33 ++++++++++++++++++++++++++++++++ >> 4 files changed, 50 insertions(+) >> >> diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug >> index 9f363c143d86..a4e7d90a45d2 100644 >> --- a/arch/powerpc/Kconfig.debug >> +++ b/arch/powerpc/Kconfig.debug >> @@ -276,6 +276,11 @@ config PPC_EARLY_DEBUG_OPAL_HVSI >> Select this to enable early debugging for the PowerNV platform >> using an "hvsi" console >> >> +config PPC_EARLY_DEBUG_16550 >> + bool "Serial 16550" >> + help >> + Select this to enable early debugging via Serial 16550 console >> + >> config PPC_EARLY_DEBUG_MEMCONS >> bool "In memory console" >> help >> @@ -355,6 +360,15 @@ config PPC_EARLY_DEBUG_CPM_ADDR >> platform probing is done, all platforms selected must >> share the same address. >> >> +config PPC_EARLY_DEBUG_16550_PHYSADDR >> + hex "Early debug Serial 16550 physical address" >> + depends on PPC_EARLY_DEBUG_16550 > > Is there any chance that you could provide a default value here > so that 'make olddefconfig' does not end up like it does > without having a default value? I did a few tests and it seems that a default doesn't help. I tried setting 'default n' to PPC_EARLY_DEBUG_16550 but I still get a prompt when doing an oldconfig. But only if you have CONFIG_PPC_EARLY_DEBUG=y in your old config. But that's expected behaviour when doing 'make oldconfig', isn't it ? Or are you meaning a defconfig ? Because I get what you describe when doing 83xx/mpc836x_rdk_defconfig. And I agree with you this is going to create problems. > > CONFIG_PPC_EARLY_DEBUG_16550=y > # CONFIG_PPC_EARLY_DEBUG_MEMCONS is not set > CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR= > CONFIG_PPC_EARLY_DEBUG_16550_STRIDE=1 > > which then causes a kconfig prompt when starting > the build... Maybe a solution is to make PPC_EARLY_DEBUG_MEMCONS the default, doing that I get no change from before. But that changes the behaviour for mpc885_ads_defconfig, so it is not the solution. So I think the only solution is to provide a default value to PPC_EARLY_DEBUG_16550_PHYSADDR, just like it is done for PPC_EARLY_DEBUG_CPM_ADDR. > >> + >> +config PPC_EARLY_DEBUG_16550_STRIDE >> + int "Early debug Serial 16550 stride" >> + depends on PPC_EARLY_DEBUG_16550 >> + default 1 >> + >> config FAIL_IOMMU >> bool "Fault-injection capability for IOMMU" >> depends on FAULT_INJECTION > > Thanks.
Le 20/08/2022 à 00:38, Pali Rohár a écrit : > On Friday 19 August 2022 15:34:14 Randy Dunlap wrote: >> Hi-- >> >> On 8/19/22 14:12, Pali Rohár wrote: >>> Currently powerpc early debugging contains lot of platform specific >>> options, but does not support standard UART / serial 16550 console. >>> >>> Later legacy_serial.c code supports registering UART as early debug console >>> from device tree but it is not early during booting, but rather later after >>> machine description code finishes. >>> >>> So for real early debugging via UART is current code unsuitable. >>> >>> Add support for new early debugging option CONFIG_PPC_EARLY_DEBUG_16550 >>> which enable Serial 16550 console on address defined by new option >>> CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR and by stride by option >>> CONFIG_PPC_EARLY_DEBUG_16550_STRIDE. >>> >>> With this change it is possible to debug powerpc machine descriptor code. >>> For example this early debugging code can print on serial console also >>> "No suitable machine description found" error which is done before >>> legacy_serial.c code. >>> >>> Signed-off-by: Pali Rohár <pali@kernel.org> >>> --- >>> Tested on P2020 board. It allowed me do debug and implement this patch series: >>> https://lore.kernel.org/linuxppc-dev/20220819191557.28116-1-pali@kernel.org/ >>> --- >>> arch/powerpc/Kconfig.debug | 14 ++++++++++++++ >>> arch/powerpc/include/asm/udbg.h | 1 + >>> arch/powerpc/kernel/udbg.c | 2 ++ >>> arch/powerpc/kernel/udbg_16550.c | 33 ++++++++++++++++++++++++++++++++ >>> 4 files changed, 50 insertions(+) >>> >>> diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug >>> index 9f363c143d86..a4e7d90a45d2 100644 >>> --- a/arch/powerpc/Kconfig.debug >>> +++ b/arch/powerpc/Kconfig.debug >>> @@ -276,6 +276,11 @@ config PPC_EARLY_DEBUG_OPAL_HVSI >>> Select this to enable early debugging for the PowerNV platform >>> using an "hvsi" console >>> >>> +config PPC_EARLY_DEBUG_16550 >>> + bool "Serial 16550" >>> + help >>> + Select this to enable early debugging via Serial 16550 console >>> + >>> config PPC_EARLY_DEBUG_MEMCONS >>> bool "In memory console" >>> help >>> @@ -355,6 +360,15 @@ config PPC_EARLY_DEBUG_CPM_ADDR >>> platform probing is done, all platforms selected must >>> share the same address. >>> >>> +config PPC_EARLY_DEBUG_16550_PHYSADDR >>> + hex "Early debug Serial 16550 physical address" >>> + depends on PPC_EARLY_DEBUG_16550 >> >> Is there any chance that you could provide a default value here >> so that 'make olddefconfig' does not end up like it does >> without having a default value? > > No. Because there is not any default value. Physical address of 16550 is > hardly HW dependent. Possibly also bootloader dependent (if it can remap > peripherals to different physical addresses). The exact same problem exists with EARLY_DEBUG_CPM. Nevertheless there is a default CONFIG_PPC_EARLY_DEBUG_CPM_ADDR. This value is wrong for some people, but at least it avoids prompt during the build of existing defconfig. Other solution is to update the defconfigs with the good value to avoid getting an empty value. > > User _has to_ specify correct physical address if want to use early > debug 16550 console. By the wait the build robot doesn't mind. > >> CONFIG_PPC_EARLY_DEBUG_16550=y >> # CONFIG_PPC_EARLY_DEBUG_MEMCONS is not set >> CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR= >> CONFIG_PPC_EARLY_DEBUG_16550_STRIDE=1 >> >> which then causes a kconfig prompt when starting >> the build... > > Cannot we set somehow that PPC_EARLY_DEBUG_16550 would be disabled by > default when upgrading defconfig? The only solution I see is to put it at the end of the list, so that the previous default value which is PPC_EARLY_DEBUG_MEMCONS gets selected. > >>> + >>> +config PPC_EARLY_DEBUG_16550_STRIDE >>> + int "Early debug Serial 16550 stride" >>> + depends on PPC_EARLY_DEBUG_16550 >>> + default 1 >>> + >>> config FAIL_IOMMU >>> bool "Fault-injection capability for IOMMU" >>> depends on FAULT_INJECTION >> >> Thanks. >> -- >> ~Randy
Le 20/08/2022 à 00:43, Randy Dunlap a écrit : > > > On 8/19/22 15:38, Pali Rohár wrote: >> On Friday 19 August 2022 15:34:14 Randy Dunlap wrote: >>> Hi-- >>> >>> On 8/19/22 14:12, Pali Rohár wrote: >>>> Currently powerpc early debugging contains lot of platform specific >>>> options, but does not support standard UART / serial 16550 console. >>>> >>>> Later legacy_serial.c code supports registering UART as early debug console >>>> from device tree but it is not early during booting, but rather later after >>>> machine description code finishes. >>>> >>>> So for real early debugging via UART is current code unsuitable. >>>> >>>> Add support for new early debugging option CONFIG_PPC_EARLY_DEBUG_16550 >>>> which enable Serial 16550 console on address defined by new option >>>> CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR and by stride by option >>>> CONFIG_PPC_EARLY_DEBUG_16550_STRIDE. >>>> >>>> With this change it is possible to debug powerpc machine descriptor code. >>>> For example this early debugging code can print on serial console also >>>> "No suitable machine description found" error which is done before >>>> legacy_serial.c code. >>>> >>>> Signed-off-by: Pali Rohár <pali@kernel.org> >>>> --- >>>> Tested on P2020 board. It allowed me do debug and implement this patch series: >>>> https://lore.kernel.org/linuxppc-dev/20220819191557.28116-1-pali@kernel.org/ >>>> --- >>>> arch/powerpc/Kconfig.debug | 14 ++++++++++++++ >>>> arch/powerpc/include/asm/udbg.h | 1 + >>>> arch/powerpc/kernel/udbg.c | 2 ++ >>>> arch/powerpc/kernel/udbg_16550.c | 33 ++++++++++++++++++++++++++++++++ >>>> 4 files changed, 50 insertions(+) >>>> >>>> diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug >>>> index 9f363c143d86..a4e7d90a45d2 100644 >>>> --- a/arch/powerpc/Kconfig.debug >>>> +++ b/arch/powerpc/Kconfig.debug >>>> @@ -276,6 +276,11 @@ config PPC_EARLY_DEBUG_OPAL_HVSI >>>> Select this to enable early debugging for the PowerNV platform >>>> using an "hvsi" console >>>> >>>> +config PPC_EARLY_DEBUG_16550 >>>> + bool "Serial 16550" >>>> + help >>>> + Select this to enable early debugging via Serial 16550 console >>>> + >>>> config PPC_EARLY_DEBUG_MEMCONS >>>> bool "In memory console" >>>> help >>>> @@ -355,6 +360,15 @@ config PPC_EARLY_DEBUG_CPM_ADDR >>>> platform probing is done, all platforms selected must >>>> share the same address. >>>> >>>> +config PPC_EARLY_DEBUG_16550_PHYSADDR >>>> + hex "Early debug Serial 16550 physical address" >>>> + depends on PPC_EARLY_DEBUG_16550 >>> >>> Is there any chance that you could provide a default value here >>> so that 'make olddefconfig' does not end up like it does >>> without having a default value? >> >> No. Because there is not any default value. Physical address of 16550 is >> hardly HW dependent. Possibly also bootloader dependent (if it can remap >> peripherals to different physical addresses). >> >> User _has to_ specify correct physical address if want to use early >> debug 16550 console. > > OK, we'll see if it ever causes a real problem then... It does, for instance with 83xx/mpc836x_rdk_defconfig > >>> CONFIG_PPC_EARLY_DEBUG_16550=y >>> # CONFIG_PPC_EARLY_DEBUG_MEMCONS is not set >>> CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR= >>> CONFIG_PPC_EARLY_DEBUG_16550_STRIDE=1 >>> >>> which then causes a kconfig prompt when starting >>> the build... >> >> Cannot we set somehow that PPC_EARLY_DEBUG_16550 would be disabled by >> default when upgrading defconfig? > > Don't know about that. > > Thanks.
Le 19/08/2022 à 23:12, Pali Rohár a écrit : > Currently powerpc early debugging contains lot of platform specific > options, but does not support standard UART / serial 16550 console. > > Later legacy_serial.c code supports registering UART as early debug console > from device tree but it is not early during booting, but rather later after > machine description code finishes. > > So for real early debugging via UART is current code unsuitable. > > Add support for new early debugging option CONFIG_PPC_EARLY_DEBUG_16550 > which enable Serial 16550 console on address defined by new option > CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR and by stride by option > CONFIG_PPC_EARLY_DEBUG_16550_STRIDE. > > With this change it is possible to debug powerpc machine descriptor code. > For example this early debugging code can print on serial console also > "No suitable machine description found" error which is done before > legacy_serial.c code. > > Signed-off-by: Pali Rohár <pali@kernel.org> > --- > Tested on P2020 board. It allowed me do debug and implement this patch series: > https://lore.kernel.org/linuxppc-dev/20220819191557.28116-1-pali@kernel.org/ Build failure if I select it on mpc885_ads_defconfig : LD vmlinux.o MODPOST vmlinux.symvers MODINFO modules.builtin.modinfo GEN modules.builtin CC .vmlinux.export.o LD .tmp_vmlinux.kallsyms1 powerpc64-linux-ld: arch/powerpc/kernel/udbg.o: in function `udbg_early_init': /home/chleroy/linux-powerpc/arch/powerpc/kernel/udbg.c:71: undefined reference to `udbg_init_debug_16550' > --- > arch/powerpc/Kconfig.debug | 14 ++++++++++++++ > arch/powerpc/include/asm/udbg.h | 1 + > arch/powerpc/kernel/udbg.c | 2 ++ > arch/powerpc/kernel/udbg_16550.c | 33 ++++++++++++++++++++++++++++++++ > 4 files changed, 50 insertions(+) > > diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug > index 9f363c143d86..a4e7d90a45d2 100644 > --- a/arch/powerpc/Kconfig.debug > +++ b/arch/powerpc/Kconfig.debug > @@ -276,6 +276,11 @@ config PPC_EARLY_DEBUG_OPAL_HVSI > Select this to enable early debugging for the PowerNV platform > using an "hvsi" console > > +config PPC_EARLY_DEBUG_16550 > + bool "Serial 16550" > + help > + Select this to enable early debugging via Serial 16550 console > + Putting it before EARLY_DEBUG_MEMCONS means that configs that were previously selectiong EARLY_DEBUG_MEMCONS will now select EARLY_DEBUG_16550 instead. Add a dependency to PPC_UDBG_16550 to avoid the build failure I mentionned ? > config PPC_EARLY_DEBUG_MEMCONS > bool "In memory console" > help > @@ -355,6 +360,15 @@ config PPC_EARLY_DEBUG_CPM_ADDR > platform probing is done, all platforms selected must > share the same address. > > +config PPC_EARLY_DEBUG_16550_PHYSADDR > + hex "Early debug Serial 16550 physical address" > + depends on PPC_EARLY_DEBUG_16550 A default value is necessary here to avoid prompts during defconfig builds. > + > +config PPC_EARLY_DEBUG_16550_STRIDE > + int "Early debug Serial 16550 stride" > + depends on PPC_EARLY_DEBUG_16550 > + default 1 > + > config FAIL_IOMMU > bool "Fault-injection capability for IOMMU" > depends on FAULT_INJECTION > diff --git a/arch/powerpc/include/asm/udbg.h b/arch/powerpc/include/asm/udbg.h > index b4aa0d88ce2c..20b5a37ab772 100644 > --- a/arch/powerpc/include/asm/udbg.h > +++ b/arch/powerpc/include/asm/udbg.h > @@ -53,6 +53,7 @@ extern void __init udbg_init_ehv_bc(void); > extern void __init udbg_init_ps3gelic(void); > extern void __init udbg_init_debug_opal_raw(void); > extern void __init udbg_init_debug_opal_hvsi(void); > +extern void __init udbg_init_debug_16550(void); 'extern' keywork is pointless and deprecated for function prototypes, please don't add new ones. Checkpatch reports: CHECK: extern prototypes should be avoided in .h files #77: FILE: arch/powerpc/include/asm/udbg.h:56: +extern void __init udbg_init_debug_16550(void); > > #endif /* __KERNEL__ */ > #endif /* _ASM_POWERPC_UDBG_H */ > diff --git a/arch/powerpc/kernel/udbg.c b/arch/powerpc/kernel/udbg.c > index b1544b2f6321..92b3fc258d11 100644 > --- a/arch/powerpc/kernel/udbg.c > +++ b/arch/powerpc/kernel/udbg.c > @@ -67,6 +67,8 @@ void __init udbg_early_init(void) > udbg_init_debug_opal_raw(); > #elif defined(CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI) > udbg_init_debug_opal_hvsi(); > +#elif defined(CONFIG_PPC_EARLY_DEBUG_16550) > + udbg_init_debug_16550(); > #endif > > #ifdef CONFIG_PPC_EARLY_DEBUG > diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c > index d3942de254c6..46f2d831d7c9 100644 > --- a/arch/powerpc/kernel/udbg_16550.c > +++ b/arch/powerpc/kernel/udbg_16550.c > @@ -8,6 +8,7 @@ > #include <asm/udbg.h> > #include <asm/io.h> > #include <asm/reg_a2.h> > +#include <asm/early_ioremap.h> > > extern u8 real_readb(volatile u8 __iomem *addr); > extern void real_writeb(u8 data, volatile u8 __iomem *addr); > @@ -335,3 +336,35 @@ void __init udbg_init_debug_microwatt(void) > } > > #endif /* CONFIG_PPC_EARLY_DEBUG_MICROWATT */ > + > +#ifdef CONFIG_PPC_EARLY_DEBUG_16550 > + > +static void __iomem *udbg_uart_early_addr; > + > +void __init udbg_init_debug_16550(void) > +{ > + udbg_uart_early_addr = early_ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000); > + udbg_uart_init_mmio(udbg_uart_early_addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE); > +} > + > +static int __init udbg_init_debug_16550_ioremap(void) > +{ > + void __iomem *addr; > + > + if (!udbg_uart_early_addr) > + return 0; > + > + addr = ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000); > + if (WARN_ON(!addr)) > + return -ENOMEM; > + > + udbg_uart_init_mmio(addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE); > + early_iounmap(udbg_uart_early_addr, 0x1000); > + udbg_uart_early_addr = NULL; > + > + return 0; > +} > + > +early_initcall(udbg_init_debug_16550_ioremap); > + > +#endif /* CONFIG_PPC_EARLY_DEBUG_16550 */
On Monday 22 August 2022 14:13:30 Christophe Leroy wrote: > >> CONFIG_PPC_EARLY_DEBUG_16550=y > >> # CONFIG_PPC_EARLY_DEBUG_MEMCONS is not set > >> CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR= > >> CONFIG_PPC_EARLY_DEBUG_16550_STRIDE=1 > >> > >> which then causes a kconfig prompt when starting > >> the build... > > > > Cannot we set somehow that PPC_EARLY_DEBUG_16550 would be disabled by > > default when upgrading defconfig? > > The only solution I see is to put it at the end of the list, so that the > previous default value which is PPC_EARLY_DEBUG_MEMCONS gets selected. Does it work for all cases? If yes, then it looks like an elegant solution.
On Monday 22 August 2022 14:25:57 Christophe Leroy wrote: > Le 19/08/2022 à 23:12, Pali Rohár a écrit : > > Currently powerpc early debugging contains lot of platform specific > > options, but does not support standard UART / serial 16550 console. > > > > Later legacy_serial.c code supports registering UART as early debug console > > from device tree but it is not early during booting, but rather later after > > machine description code finishes. > > > > So for real early debugging via UART is current code unsuitable. > > > > Add support for new early debugging option CONFIG_PPC_EARLY_DEBUG_16550 > > which enable Serial 16550 console on address defined by new option > > CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR and by stride by option > > CONFIG_PPC_EARLY_DEBUG_16550_STRIDE. > > > > With this change it is possible to debug powerpc machine descriptor code. > > For example this early debugging code can print on serial console also > > "No suitable machine description found" error which is done before > > legacy_serial.c code. > > > > Signed-off-by: Pali Rohár <pali@kernel.org> > > --- > > Tested on P2020 board. It allowed me do debug and implement this patch series: > > https://lore.kernel.org/linuxppc-dev/20220819191557.28116-1-pali@kernel.org/ > > Build failure if I select it on mpc885_ads_defconfig : > > LD vmlinux.o > MODPOST vmlinux.symvers > MODINFO modules.builtin.modinfo > GEN modules.builtin > CC .vmlinux.export.o > LD .tmp_vmlinux.kallsyms1 > powerpc64-linux-ld: arch/powerpc/kernel/udbg.o: in function > `udbg_early_init': > /home/chleroy/linux-powerpc/arch/powerpc/kernel/udbg.c:71: undefined > reference to `udbg_init_debug_16550' > > > > > --- > > arch/powerpc/Kconfig.debug | 14 ++++++++++++++ > > arch/powerpc/include/asm/udbg.h | 1 + > > arch/powerpc/kernel/udbg.c | 2 ++ > > arch/powerpc/kernel/udbg_16550.c | 33 ++++++++++++++++++++++++++++++++ > > 4 files changed, 50 insertions(+) > > > > diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug > > index 9f363c143d86..a4e7d90a45d2 100644 > > --- a/arch/powerpc/Kconfig.debug > > +++ b/arch/powerpc/Kconfig.debug > > @@ -276,6 +276,11 @@ config PPC_EARLY_DEBUG_OPAL_HVSI > > Select this to enable early debugging for the PowerNV platform > > using an "hvsi" console > > > > +config PPC_EARLY_DEBUG_16550 > > + bool "Serial 16550" > > + help > > + Select this to enable early debugging via Serial 16550 console > > + > > Putting it before EARLY_DEBUG_MEMCONS means that configs that were > previously selectiong EARLY_DEBUG_MEMCONS will now select > EARLY_DEBUG_16550 instead. > > Add a dependency to PPC_UDBG_16550 to avoid the build failure I mentionned ? Yea, there is really missing dependency. I will fix it. > > config PPC_EARLY_DEBUG_MEMCONS > > bool "In memory console" > > help > > @@ -355,6 +360,15 @@ config PPC_EARLY_DEBUG_CPM_ADDR > > platform probing is done, all platforms selected must > > share the same address. > > > > +config PPC_EARLY_DEBUG_16550_PHYSADDR > > + hex "Early debug Serial 16550 physical address" > > + depends on PPC_EARLY_DEBUG_16550 > > A default value is necessary here to avoid prompts during defconfig builds. > > > + > > +config PPC_EARLY_DEBUG_16550_STRIDE > > + int "Early debug Serial 16550 stride" > > + depends on PPC_EARLY_DEBUG_16550 > > + default 1 > > + > > config FAIL_IOMMU > > bool "Fault-injection capability for IOMMU" > > depends on FAULT_INJECTION > > diff --git a/arch/powerpc/include/asm/udbg.h b/arch/powerpc/include/asm/udbg.h > > index b4aa0d88ce2c..20b5a37ab772 100644 > > --- a/arch/powerpc/include/asm/udbg.h > > +++ b/arch/powerpc/include/asm/udbg.h > > @@ -53,6 +53,7 @@ extern void __init udbg_init_ehv_bc(void); > > extern void __init udbg_init_ps3gelic(void); > > extern void __init udbg_init_debug_opal_raw(void); > > extern void __init udbg_init_debug_opal_hvsi(void); > > +extern void __init udbg_init_debug_16550(void); > > 'extern' keywork is pointless and deprecated for function prototypes, > please don't add new ones. I used extern keyword to follow existing coding style. > Checkpatch reports: > > CHECK: extern prototypes should be avoided in .h files > #77: FILE: arch/powerpc/include/asm/udbg.h:56: > +extern void __init udbg_init_debug_16550(void); > > > > > > #endif /* __KERNEL__ */ > > #endif /* _ASM_POWERPC_UDBG_H */ > > diff --git a/arch/powerpc/kernel/udbg.c b/arch/powerpc/kernel/udbg.c > > index b1544b2f6321..92b3fc258d11 100644 > > --- a/arch/powerpc/kernel/udbg.c > > +++ b/arch/powerpc/kernel/udbg.c > > @@ -67,6 +67,8 @@ void __init udbg_early_init(void) > > udbg_init_debug_opal_raw(); > > #elif defined(CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI) > > udbg_init_debug_opal_hvsi(); > > +#elif defined(CONFIG_PPC_EARLY_DEBUG_16550) > > + udbg_init_debug_16550(); > > #endif > > > > #ifdef CONFIG_PPC_EARLY_DEBUG > > diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c > > index d3942de254c6..46f2d831d7c9 100644 > > --- a/arch/powerpc/kernel/udbg_16550.c > > +++ b/arch/powerpc/kernel/udbg_16550.c > > @@ -8,6 +8,7 @@ > > #include <asm/udbg.h> > > #include <asm/io.h> > > #include <asm/reg_a2.h> > > +#include <asm/early_ioremap.h> > > > > extern u8 real_readb(volatile u8 __iomem *addr); > > extern void real_writeb(u8 data, volatile u8 __iomem *addr); > > @@ -335,3 +336,35 @@ void __init udbg_init_debug_microwatt(void) > > } > > > > #endif /* CONFIG_PPC_EARLY_DEBUG_MICROWATT */ > > + > > +#ifdef CONFIG_PPC_EARLY_DEBUG_16550 > > + > > +static void __iomem *udbg_uart_early_addr; > > + > > +void __init udbg_init_debug_16550(void) > > +{ > > + udbg_uart_early_addr = early_ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000); > > + udbg_uart_init_mmio(udbg_uart_early_addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE); > > +} > > + > > +static int __init udbg_init_debug_16550_ioremap(void) > > +{ > > + void __iomem *addr; > > + > > + if (!udbg_uart_early_addr) > > + return 0; > > + > > + addr = ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000); > > + if (WARN_ON(!addr)) > > + return -ENOMEM; > > + > > + udbg_uart_init_mmio(addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE); > > + early_iounmap(udbg_uart_early_addr, 0x1000); > > + udbg_uart_early_addr = NULL; > > + > > + return 0; > > +} > > + > > +early_initcall(udbg_init_debug_16550_ioremap); > > + > > +#endif /* CONFIG_PPC_EARLY_DEBUG_16550 */
On Mon, Aug 22, 2022 at 05:33:35PM +0200, Pali Rohár wrote: > On Monday 22 August 2022 14:25:57 Christophe Leroy wrote: > > Le 19/08/2022 à 23:12, Pali Rohár a écrit : > > > Currently powerpc early debugging contains lot of platform specific > > > options, but does not support standard UART / serial 16550 console. > > > > > > Later legacy_serial.c code supports registering UART as early debug console > > > from device tree but it is not early during booting, but rather later after > > > machine description code finishes. > > > > > > So for real early debugging via UART is current code unsuitable. > > > > > > Add support for new early debugging option CONFIG_PPC_EARLY_DEBUG_16550 > > > which enable Serial 16550 console on address defined by new option > > > CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR and by stride by option > > > CONFIG_PPC_EARLY_DEBUG_16550_STRIDE. > > > > > > With this change it is possible to debug powerpc machine descriptor code. > > > For example this early debugging code can print on serial console also > > > "No suitable machine description found" error which is done before > > > legacy_serial.c code. > > > > > > Signed-off-by: Pali Rohár <pali@kernel.org> > > > --- > > > Tested on P2020 board. It allowed me do debug and implement this patch series: > > > https://lore.kernel.org/linuxppc-dev/20220819191557.28116-1-pali@kernel.org/ > > > > Build failure if I select it on mpc885_ads_defconfig : > > > > LD vmlinux.o > > MODPOST vmlinux.symvers > > MODINFO modules.builtin.modinfo > > GEN modules.builtin > > CC .vmlinux.export.o > > LD .tmp_vmlinux.kallsyms1 > > powerpc64-linux-ld: arch/powerpc/kernel/udbg.o: in function > > `udbg_early_init': > > /home/chleroy/linux-powerpc/arch/powerpc/kernel/udbg.c:71: undefined > > reference to `udbg_init_debug_16550' > > > > > > > > > --- > > > arch/powerpc/Kconfig.debug | 14 ++++++++++++++ > > > arch/powerpc/include/asm/udbg.h | 1 + > > > arch/powerpc/kernel/udbg.c | 2 ++ > > > arch/powerpc/kernel/udbg_16550.c | 33 ++++++++++++++++++++++++++++++++ > > > 4 files changed, 50 insertions(+) > > > > > > diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug > > > index 9f363c143d86..a4e7d90a45d2 100644 > > > --- a/arch/powerpc/Kconfig.debug > > > +++ b/arch/powerpc/Kconfig.debug > > > @@ -276,6 +276,11 @@ config PPC_EARLY_DEBUG_OPAL_HVSI > > > Select this to enable early debugging for the PowerNV platform > > > using an "hvsi" console > > > > > > +config PPC_EARLY_DEBUG_16550 > > > + bool "Serial 16550" > > > + help > > > + Select this to enable early debugging via Serial 16550 console > > > + > > > > Putting it before EARLY_DEBUG_MEMCONS means that configs that were > > previously selectiong EARLY_DEBUG_MEMCONS will now select > > EARLY_DEBUG_16550 instead. > > > > Add a dependency to PPC_UDBG_16550 to avoid the build failure I mentionned ? > > Yea, there is really missing dependency. I will fix it. > > > > config PPC_EARLY_DEBUG_MEMCONS > > > bool "In memory console" > > > help > > > @@ -355,6 +360,15 @@ config PPC_EARLY_DEBUG_CPM_ADDR > > > platform probing is done, all platforms selected must > > > share the same address. > > > > > > +config PPC_EARLY_DEBUG_16550_PHYSADDR > > > + hex "Early debug Serial 16550 physical address" > > > + depends on PPC_EARLY_DEBUG_16550 > > > > A default value is necessary here to avoid prompts during defconfig builds. > > > > > + > > > +config PPC_EARLY_DEBUG_16550_STRIDE > > > + int "Early debug Serial 16550 stride" > > > + depends on PPC_EARLY_DEBUG_16550 > > > + default 1 > > > + > > > config FAIL_IOMMU > > > bool "Fault-injection capability for IOMMU" > > > depends on FAULT_INJECTION > > > diff --git a/arch/powerpc/include/asm/udbg.h b/arch/powerpc/include/asm/udbg.h > > > index b4aa0d88ce2c..20b5a37ab772 100644 > > > --- a/arch/powerpc/include/asm/udbg.h > > > +++ b/arch/powerpc/include/asm/udbg.h > > > @@ -53,6 +53,7 @@ extern void __init udbg_init_ehv_bc(void); > > > extern void __init udbg_init_ps3gelic(void); > > > extern void __init udbg_init_debug_opal_raw(void); > > > extern void __init udbg_init_debug_opal_hvsi(void); > > > +extern void __init udbg_init_debug_16550(void); > > > > 'extern' keywork is pointless and deprecated for function prototypes, > > please don't add new ones. > > I used extern keyword to follow existing coding style. In this case it's better to remove existing extern specifications in the surrounding lines. Increasing a bit the footprint of the patch is justified, and does not significantly increase the risk of conflicts with other patches, unlike the gratuitous churn we see sometimes. Gabriel > > > Checkpatch reports: > > > > CHECK: extern prototypes should be avoided in .h files > > #77: FILE: arch/powerpc/include/asm/udbg.h:56: > > +extern void __init udbg_init_debug_16550(void); > > > > > > > > > > #endif /* __KERNEL__ */ > > > #endif /* _ASM_POWERPC_UDBG_H */ > > > diff --git a/arch/powerpc/kernel/udbg.c b/arch/powerpc/kernel/udbg.c > > > index b1544b2f6321..92b3fc258d11 100644 > > > --- a/arch/powerpc/kernel/udbg.c > > > +++ b/arch/powerpc/kernel/udbg.c > > > @@ -67,6 +67,8 @@ void __init udbg_early_init(void) > > > udbg_init_debug_opal_raw(); > > > #elif defined(CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI) > > > udbg_init_debug_opal_hvsi(); > > > +#elif defined(CONFIG_PPC_EARLY_DEBUG_16550) > > > + udbg_init_debug_16550(); > > > #endif > > > > > > #ifdef CONFIG_PPC_EARLY_DEBUG > > > diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c > > > index d3942de254c6..46f2d831d7c9 100644 > > > --- a/arch/powerpc/kernel/udbg_16550.c > > > +++ b/arch/powerpc/kernel/udbg_16550.c > > > @@ -8,6 +8,7 @@ > > > #include <asm/udbg.h> > > > #include <asm/io.h> > > > #include <asm/reg_a2.h> > > > +#include <asm/early_ioremap.h> > > > > > > extern u8 real_readb(volatile u8 __iomem *addr); > > > extern void real_writeb(u8 data, volatile u8 __iomem *addr); > > > @@ -335,3 +336,35 @@ void __init udbg_init_debug_microwatt(void) > > > } > > > > > > #endif /* CONFIG_PPC_EARLY_DEBUG_MICROWATT */ > > > + > > > +#ifdef CONFIG_PPC_EARLY_DEBUG_16550 > > > + > > > +static void __iomem *udbg_uart_early_addr; > > > + > > > +void __init udbg_init_debug_16550(void) > > > +{ > > > + udbg_uart_early_addr = early_ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000); > > > + udbg_uart_init_mmio(udbg_uart_early_addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE); > > > +} > > > + > > > +static int __init udbg_init_debug_16550_ioremap(void) > > > +{ > > > + void __iomem *addr; > > > + > > > + if (!udbg_uart_early_addr) > > > + return 0; > > > + > > > + addr = ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000); > > > + if (WARN_ON(!addr)) > > > + return -ENOMEM; > > > + > > > + udbg_uart_init_mmio(addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE); > > > + early_iounmap(udbg_uart_early_addr, 0x1000); > > > + udbg_uart_early_addr = NULL; > > > + > > > + return 0; > > > +} > > > + > > > +early_initcall(udbg_init_debug_16550_ioremap); > > > + > > > +#endif /* CONFIG_PPC_EARLY_DEBUG_16550 */
diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug index 9f363c143d86..a4e7d90a45d2 100644 --- a/arch/powerpc/Kconfig.debug +++ b/arch/powerpc/Kconfig.debug @@ -276,6 +276,11 @@ config PPC_EARLY_DEBUG_OPAL_HVSI Select this to enable early debugging for the PowerNV platform using an "hvsi" console +config PPC_EARLY_DEBUG_16550 + bool "Serial 16550" + help + Select this to enable early debugging via Serial 16550 console + config PPC_EARLY_DEBUG_MEMCONS bool "In memory console" help @@ -355,6 +360,15 @@ config PPC_EARLY_DEBUG_CPM_ADDR platform probing is done, all platforms selected must share the same address. +config PPC_EARLY_DEBUG_16550_PHYSADDR + hex "Early debug Serial 16550 physical address" + depends on PPC_EARLY_DEBUG_16550 + +config PPC_EARLY_DEBUG_16550_STRIDE + int "Early debug Serial 16550 stride" + depends on PPC_EARLY_DEBUG_16550 + default 1 + config FAIL_IOMMU bool "Fault-injection capability for IOMMU" depends on FAULT_INJECTION diff --git a/arch/powerpc/include/asm/udbg.h b/arch/powerpc/include/asm/udbg.h index b4aa0d88ce2c..20b5a37ab772 100644 --- a/arch/powerpc/include/asm/udbg.h +++ b/arch/powerpc/include/asm/udbg.h @@ -53,6 +53,7 @@ extern void __init udbg_init_ehv_bc(void); extern void __init udbg_init_ps3gelic(void); extern void __init udbg_init_debug_opal_raw(void); extern void __init udbg_init_debug_opal_hvsi(void); +extern void __init udbg_init_debug_16550(void); #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_UDBG_H */ diff --git a/arch/powerpc/kernel/udbg.c b/arch/powerpc/kernel/udbg.c index b1544b2f6321..92b3fc258d11 100644 --- a/arch/powerpc/kernel/udbg.c +++ b/arch/powerpc/kernel/udbg.c @@ -67,6 +67,8 @@ void __init udbg_early_init(void) udbg_init_debug_opal_raw(); #elif defined(CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI) udbg_init_debug_opal_hvsi(); +#elif defined(CONFIG_PPC_EARLY_DEBUG_16550) + udbg_init_debug_16550(); #endif #ifdef CONFIG_PPC_EARLY_DEBUG diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c index d3942de254c6..46f2d831d7c9 100644 --- a/arch/powerpc/kernel/udbg_16550.c +++ b/arch/powerpc/kernel/udbg_16550.c @@ -8,6 +8,7 @@ #include <asm/udbg.h> #include <asm/io.h> #include <asm/reg_a2.h> +#include <asm/early_ioremap.h> extern u8 real_readb(volatile u8 __iomem *addr); extern void real_writeb(u8 data, volatile u8 __iomem *addr); @@ -335,3 +336,35 @@ void __init udbg_init_debug_microwatt(void) } #endif /* CONFIG_PPC_EARLY_DEBUG_MICROWATT */ + +#ifdef CONFIG_PPC_EARLY_DEBUG_16550 + +static void __iomem *udbg_uart_early_addr; + +void __init udbg_init_debug_16550(void) +{ + udbg_uart_early_addr = early_ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000); + udbg_uart_init_mmio(udbg_uart_early_addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE); +} + +static int __init udbg_init_debug_16550_ioremap(void) +{ + void __iomem *addr; + + if (!udbg_uart_early_addr) + return 0; + + addr = ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000); + if (WARN_ON(!addr)) + return -ENOMEM; + + udbg_uart_init_mmio(addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE); + early_iounmap(udbg_uart_early_addr, 0x1000); + udbg_uart_early_addr = NULL; + + return 0; +} + +early_initcall(udbg_init_debug_16550_ioremap); + +#endif /* CONFIG_PPC_EARLY_DEBUG_16550 */
Currently powerpc early debugging contains lot of platform specific options, but does not support standard UART / serial 16550 console. Later legacy_serial.c code supports registering UART as early debug console from device tree but it is not early during booting, but rather later after machine description code finishes. So for real early debugging via UART is current code unsuitable. Add support for new early debugging option CONFIG_PPC_EARLY_DEBUG_16550 which enable Serial 16550 console on address defined by new option CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR and by stride by option CONFIG_PPC_EARLY_DEBUG_16550_STRIDE. With this change it is possible to debug powerpc machine descriptor code. For example this early debugging code can print on serial console also "No suitable machine description found" error which is done before legacy_serial.c code. Signed-off-by: Pali Rohár <pali@kernel.org> --- Tested on P2020 board. It allowed me do debug and implement this patch series: https://lore.kernel.org/linuxppc-dev/20220819191557.28116-1-pali@kernel.org/ --- arch/powerpc/Kconfig.debug | 14 ++++++++++++++ arch/powerpc/include/asm/udbg.h | 1 + arch/powerpc/kernel/udbg.c | 2 ++ arch/powerpc/kernel/udbg_16550.c | 33 ++++++++++++++++++++++++++++++++ 4 files changed, 50 insertions(+)