[PATCH RFC u-boot-mvebu] arm: kirkwood: Move internal registers in arch_very_early_init() function
Tony Dinh
mibodhi at gmail.com
Sun Mar 12 22:30:29 CET 2023
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.
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
> > >
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