[PATCH RFC u-boot-mvebu] arm: kirkwood: Move internal registers in arch_very_early_init() function
Tony Dinh
mibodhi at gmail.com
Tue Mar 14 07:02:49 CET 2023
On Sun, Mar 12, 2023 at 5:12 PM Tony Dinh <mibodhi at gmail.com> wrote:
>
> Hi Pali,
>
> On Sun, Mar 12, 2023 at 2:38 PM Pali Rohár <pali at kernel.org> wrote:
> >
> > On Sunday 12 March 2023 14:30:29 Tony Dinh wrote:
> > > Hi Pali,
> > >
> > > On Sat, Mar 11, 2023 at 4:29 PM Pali Rohár <pali at kernel.org> wrote:
> > > >
> > > > On Saturday 11 March 2023 15:47:29 Tony Dinh wrote:
> > > > > Hi Pali,
> > > > >
> > > > > On Sat, Mar 11, 2023 at 2:57 AM Pali Rohár <pali at kernel.org> wrote:
> > > > > >
> > > > > > Same change as was done for mvebu in commit 5bb2c550b11e ("arm: mvebu: Move
> > > > > > internal registers in arch_very_early_init() function") but for kirkwood.
> > > > > >
> > > > > > Signed-off-by: Pali Rohár <pali at kernel.org>
> > > > > > ---
> > > > > > Hello! Please test this RFC patch on more Kirkwood boards if there is
> > > > > > any issue with it.
> > > > >
> > > > > I've run a regression test with this patch (Debug UART is not
> > > > > enabled). And everything was OK. No change in behavior.
> > > >
> > > > Ok! Thanks for testing.
> > > >
> > > > > However, when I turned on Debug UART on the nsa310s (88F6702) board,
> > > > > and ran with kwboot, it froze right away upon starting. Unrelated to
> > > > > this patch, I believe DEBUG_UART has been broken for Kirkwood lately,
> > > > > perhaps sometime late December to present, but I did not have time to
> > > > > track it down. Here is the last thread that I had Debug UART working
> > > > > on the Pogo V4 (88F6192):
> > > > > https://lists.denx.de/pipermail/u-boot/2022-December/502605.html
> > > > >
> > > > > For reference, here is my local patch to configure the NSA310S, in
> > > > > addition to this patch.
> > > >
> > > > I do not know what could broke it, but I see there two things which you
> > > > could change in your configuration.
> > > >
> > > > 1. Try to set UART shift register to 2. Not sure what is default but in
> > > > kirkwood.dtsi file it is 2.
> > > >
> > > > CONFIG_DEBUG_UART_SHIFT=2
> > > >
> > > > 2. Recheck UART clock. In kw88f6281.h is defined that TCLK is either
> > > > 166666667 or 200000000. And it is configured by strapping pins. TCLK
> > > > cannot be 250000000 on 6281 for sure. I do not know to which clock
> > > > is connected UART base clock, but my guess is that it is TCLK.
> > >
> > > Thanks for the suggestion. Indeed, the combination of
> > > CONFIG_DEBUG_UART_CLOCK=166666667 and CONFIG_DEBUG_UART_SHIFT=2 works
> > > as it should (88F6702/88F6192 TCLK=166666667).
> > >
> > > Without setting CONFIG_DEBUG_UART_SHIFT in defconfig, it is default to 0.
> > >
> > > CONFIG_DEBUG_UART_SHIFT=2 is the key here, because U-Boot does not
> > > hang with CONFIG_DEBUG_UART_CLOCK=250000000. The board runs OK, but
> > > the Debug UART announcement output is gibberish.
> >
> > Perfect! So ideally send a patch with adding those options into
> > nsa310s_defconfig. I guess that CONFIG_DEBUG_UART_ANNOUNCE is not
> > needed.
>
> Sure, I will do that. In the meantime, I ran some more tests and here
> are some interesting results (thanks to Debug UART working now).
>
> 1. I've confirmed that, at the moment, we need your patch to see
> DEBUG_UART early output for Kirkwood. Without it, with DEBUG_UART
> configured correctly, I don't see any output on this board. It will
> run fine but behaving like there is no Debug UART enabled.
>
> 2. There is no need for the u-boot,dm-pre-reloc tag on Kirkwood
> boards. The serial-uclass function serial_check_stdout() binds it
> anyway ff the console is not marked to be bound before relocation:
> https://github.com/u-boot/u-boot/blob/master/drivers/serial/serial-uclass.c#L67
>
> 3. The previous problem we saw with the Pogo V4 (Kirwood 6192) DM
> serial might be related to all this. Hopefully with your patch I can
> track it down further.
>
> Thanks,
> Tony
>
> >
> > > So I guess back on the Dec 19th build, perhaps I was just lucky that
> > > some internal values were used for Kirkwood, but not CONFIG_xxx.
> > >
> > > Thanks,
> > > Tony
> > >
> > > > > diff --git a/configs/nsa310s_defconfig b/configs/nsa310s_defconfig
> > > > > index 76839e62dd..4bef35d576 100644
> > > > > --- a/configs/nsa310s_defconfig
> > > > > +++ b/configs/nsa310s_defconfig
> > > > > @@ -15,8 +15,11 @@ CONFIG_ENV_SIZE=0x20000
> > > > > CONFIG_ENV_OFFSET=0xE0000
> > > > > CONFIG_DEFAULT_DEVICE_TREE="kirkwood-nsa310s"
> > > > > CONFIG_SYS_PROMPT="NSA310s> "
> > > > > +CONFIG_DEBUG_UART_BASE=0xf1012000
> > > > > +CONFIG_DEBUG_UART_CLOCK=250000000
> > > > > CONFIG_IDENT_STRING="\nZyXEL NSA310S/320S 1/2-Bay Power Media Server"
> > > > > CONFIG_SYS_LOAD_ADDR=0x800000
> > > > > +CONFIG_DEBUG_UART=y
> > > > > CONFIG_DISTRO_DEFAULTS=y
> > > > > CONFIG_BOOTDELAY=3
> > > > > CONFIG_USE_PREBOOT=y
> > > > > @@ -50,6 +53,7 @@ CONFIG_MTD_RAW_NAND=y
> > > > > CONFIG_PHY_MARVELL=y
> > > > > CONFIG_MVGBE=y
> > > > > CONFIG_MII=y
> > > > > +CONFIG_DEBUG_UART_ANNOUNCE=y
> > > > > CONFIG_USB=y
> > > > > CONFIG_USB_EHCI_HCD=y
> > > > > CONFIG_UBIFS_SILENCE_MSG=y
> > > > >
> > > > > diff --git a/arch/arm/dts/kirkwood-nsa310s.dts
> > > > > b/arch/arm/dts/kirkwood-nsa310s.dts
> > > > > index 09ee76c2a2..2df45aa6da 100644
> > > > > --- a/arch/arm/dts/kirkwood-nsa310s.dts
> > > > > +++ b/arch/arm/dts/kirkwood-nsa310s.dts
> > > > > @@ -22,6 +22,10 @@
> > > > > reg = <0x00000000 0x10000000>;
> > > > > };
> > > > >
> > > > > + aliases {
> > > > > + serial0 = &uart0;
> > > > > + };
> > > > > +
> > > > > chosen {
> > > > > bootargs = "console=ttyS0,115200";
> > > > > stdout-path = &uart0;
> > > > > @@ -317,3 +321,8 @@
> > > > > &pcie0 {
> > > > > status = "okay";
> > > > > };
> > > > > +
> > > > > +&uart0 {
> > > > > + status = "okay";
> > > > > + u-boot,dm-pre-reloc;
> > > > > +};
> > > > >
> > > > > If anybody is available to test this patch with Debug UART enabled, it
> > > > > would be great. I'll wait a few days and if there is no suggestion, I
> > > > > would do a bisect from Dec 19th.
> > > > >
> > > > > Thanks,
> > > > > Tony
> > > > >
> > > > > > ---
> > > > > > arch/arm/mach-kirkwood/Kconfig | 2 ++
> > > > > > arch/arm/mach-kirkwood/Makefile | 1 +
> > > > > > arch/arm/mach-kirkwood/cpu.c | 3 ---
> > > > > > arch/arm/mach-kirkwood/lowlevel.S | 12 ++++++++++++
> > > > > > 4 files changed, 15 insertions(+), 3 deletions(-)
> > > > > > create mode 100644 arch/arm/mach-kirkwood/lowlevel.S
> > > > > >
> > > > > > diff --git a/arch/arm/mach-kirkwood/Kconfig b/arch/arm/mach-kirkwood/Kconfig
> > > > > > index c8a193dd4cdf..ba39e9ae416e 100644
> > > > > > --- a/arch/arm/mach-kirkwood/Kconfig
> > > > > > +++ b/arch/arm/mach-kirkwood/Kconfig
> > > > > > @@ -5,9 +5,11 @@ config FEROCEON_88FR131
> > > > > >
> > > > > > config KW88F6192
> > > > > > bool
> > > > > > + select ARCH_VERY_EARLY_INIT
> > > > > >
> > > > > > config KW88F6281
> > > > > > bool
> > > > > > + select ARCH_VERY_EARLY_INIT
> > > > > >
> > > > > > config SHEEVA_88SV131
> > > > > > bool
> > > > > > diff --git a/arch/arm/mach-kirkwood/Makefile b/arch/arm/mach-kirkwood/Makefile
> > > > > > index 3b2eef8d5419..0fb5a2326f5f 100644
> > > > > > --- a/arch/arm/mach-kirkwood/Makefile
> > > > > > +++ b/arch/arm/mach-kirkwood/Makefile
> > > > > > @@ -6,6 +6,7 @@
> > > > > >
> > > > > > obj-y = cpu.o
> > > > > > obj-y += cache.o
> > > > > > +obj-y += lowlevel.o
> > > > > > obj-y += mpp.o
> > > > > >
> > > > > > # cpu.o and cache.o contain CP15 instructions which cannot be run in
> > > > > > diff --git a/arch/arm/mach-kirkwood/cpu.c b/arch/arm/mach-kirkwood/cpu.c
> > > > > > index df3e8f11782a..2b493b36c20d 100644
> > > > > > --- a/arch/arm/mach-kirkwood/cpu.c
> > > > > > +++ b/arch/arm/mach-kirkwood/cpu.c
> > > > > > @@ -189,9 +189,6 @@ int arch_cpu_init(void)
> > > > > > struct kwcpu_registers *cpureg =
> > > > > > (struct kwcpu_registers *)KW_CPU_REG_BASE;
> > > > > >
> > > > > > - /* Linux expects the internal registers to be at 0xf1000000 */
> > > > > > - writel(KW_REGS_PHY_BASE, KW_OFFSET_REG);
> > > > > > -
> > > > > > /* Enable and invalidate L2 cache in write through mode */
> > > > > > writel(readl(&cpureg->l2_cfg) | 0x18, &cpureg->l2_cfg);
> > > > > > invalidate_l2_cache();
> > > > > > diff --git a/arch/arm/mach-kirkwood/lowlevel.S b/arch/arm/mach-kirkwood/lowlevel.S
> > > > > > new file mode 100644
> > > > > > index 000000000000..3b339f97f056
> > > > > > --- /dev/null
> > > > > > +++ b/arch/arm/mach-kirkwood/lowlevel.S
> > > > > > @@ -0,0 +1,12 @@
> > > > > > +/* SPDX-License-Identifier: GPL-2.0+ */
> > > > > > +
> > > > > > +#include <config.h>
> > > > > > +#include <linux/linkage.h>
> > > > > > +
> > > > > > +ENTRY(arch_very_early_init)
> > > > > > + /* Move internal registers from KW_OFFSET_REG to KW_REGS_PHY_BASE */
> > > > > > + ldr r0, =KW_REGS_PHY_BASE
> > > > > > + ldr r1, =KW_OFFSET_REG
> > > > > > + str r0, [r1]
> > > > > > + bx lr
> > > > > > +ENDPROC(arch_very_early_init)
> > > > > > --
> > > > > > 2.20.1
> > > > > >
All checked out OK on these Kirkwood boards:
Zyxel NSA310S (88F6702)
Cloudengine Pogo V4 (88F6192)
Seagate Goflex Home (88F6281)
Tested-by: Tony Dinh <mibodhi at gmail.com>
Thanks,
Tony
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