Re: [PATCH v7 1/3] arm: npcm: add basic support for Nuvoton BMCs

[Brendan Higgins <brendanhiggins@google.com>]

On Thu, Oct 26, 2017 at 4:45 AM, Tomer Maimon <tmaimon77@gmail.com> wrote:
> Hi Brendan,
>
> Sorry for the delay,
>
> On 21 October 2017 at 00:08, Russell King - ARM Linux
> <linux@armlinux.org.uk> wrote:
>> On Fri, Oct 20, 2017 at 01:57:47PM -0700, Brendan Higgins wrote:
>>> On Fri, Oct 20, 2017 at 3:48 AM, Russell King - ARM Linux
>>> <linux@armlinux.org.uk> wrote:
>>> > On Thu, Oct 19, 2017 at 03:50:48PM -0700, Brendan Higgins wrote:
>>> >> Adds basic support for the Nuvoton NPCM750 BMC.
>>> >>
>>> >> Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
>>> >> Reviewed-by: Tomer Maimon <tmaimon77@gmail.com>
>>> >> Reviewed-by: Avi Fishman <avifishman70@gmail.com>
>>> >> Tested-by: Tomer Maimon <tmaimon77@gmail.com>
>>> >> Tested-by: Avi Fishman <avifishman70@gmail.com>
>>> >> ---
>>> >>  arch/arm/Kconfig             |  2 +
>>> >>  arch/arm/Makefile            |  1 +
>>> >>  arch/arm/mach-npcm/Kconfig   | 48 ++++++++++++++++++++++++
>>> >>  arch/arm/mach-npcm/Makefile  |  3 ++
>>> >>  arch/arm/mach-npcm/headsmp.S | 17 +++++++++
>>> >>  arch/arm/mach-npcm/npcm7xx.c | 34 +++++++++++++++++
>>> >>  arch/arm/mach-npcm/platsmp.c | 88 ++++++++++++++++++++++++++++++++++++++++++++
>>> >>  7 files changed, 193 insertions(+)
>>> >>  create mode 100644 arch/arm/mach-npcm/Kconfig
>>> >>  create mode 100644 arch/arm/mach-npcm/Makefile
>>> >>  create mode 100644 arch/arm/mach-npcm/headsmp.S
>>> >>  create mode 100644 arch/arm/mach-npcm/npcm7xx.c
>>> >>  create mode 100644 arch/arm/mach-npcm/platsmp.c
>>> >>
>>> >> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>>> >> index 61a0cb15067e..05543f1cfbde 100644
>>> >> --- a/arch/arm/Kconfig
>>> >> +++ b/arch/arm/Kconfig
>>> >> @@ -782,6 +782,8 @@ source "arch/arm/mach-netx/Kconfig"
>>> >>
>>> >>  source "arch/arm/mach-nomadik/Kconfig"
>>> >>
>>> >> +source "arch/arm/mach-npcm/Kconfig"
>>> >> +
>>> >>  source "arch/arm/mach-nspire/Kconfig"
>>> >>
>>> >>  source "arch/arm/plat-omap/Kconfig"
>>> >> diff --git a/arch/arm/Makefile b/arch/arm/Makefile
>>> >> index 47d3a1ab08d2..60ca50c7d762 100644
>>> >> --- a/arch/arm/Makefile
>>> >> +++ b/arch/arm/Makefile
>>> >> @@ -191,6 +191,7 @@ machine-$(CONFIG_ARCH_MEDIATEK)           += mediatek
>>> >>  machine-$(CONFIG_ARCH_MXS)           += mxs
>>> >>  machine-$(CONFIG_ARCH_NETX)          += netx
>>> >>  machine-$(CONFIG_ARCH_NOMADIK)               += nomadik
>>> >> +machine-$(CONFIG_ARCH_NPCM)          += npcm
>>> >>  machine-$(CONFIG_ARCH_NSPIRE)                += nspire
>>> >>  machine-$(CONFIG_ARCH_OXNAS)         += oxnas
>>> >>  machine-$(CONFIG_ARCH_OMAP1)         += omap1
>>> >> diff --git a/arch/arm/mach-npcm/Kconfig b/arch/arm/mach-npcm/Kconfig
>>> >> new file mode 100644
>>> >> index 000000000000..21dfa8ce828f
>>> >> --- /dev/null
>>> >> +++ b/arch/arm/mach-npcm/Kconfig
>>> >> @@ -0,0 +1,48 @@
>>> >> +menuconfig ARCH_NPCM
>>> >> +     bool "Nuvoton NPCM Architecture"
>>> >> +     select ARCH_REQUIRE_GPIOLIB
>>> >> +     select USE_OF
>>> >> +     select PINCTRL
>>> >> +     select PINCTRL_NPCM7XX
>>> >> +
>>> >> +if ARCH_NPCM
>>> >> +
>>> >> +comment "NPCMX50 CPU type"
>>> >> +
>>> >> +config CPU_NPCM750
>
> I started the upstream process of NPCM7xx clocksource driver, I got
> the following comment
> https://www.spinics.net/lists/devicetree/msg197916.html
>
> Is it possible to modify the the architecture configuration name to
> ARCH_NPCM7XX.

You mean the CPU config: CPU_NPCM7XX?

I think the ARCH_NPCM is right, since that corresponds to this directory
which is for all ARM Nuvoton BMCs.

>
>>> >> +     depends on ARCH_NPCM && ARCH_MULTI_V7
>>> >> +     bool "Support for NPCM750 BMC CPU (Poleg)"
>>> >> +     select CACHE_L2X0
>>> >> +     select CPU_V7
>>> >> +     select ARM_GIC
>>> >> +     select HAVE_SMP
>>> >> +     select SMP
>>> >> +     select SMP_ON_UP
>>> >> +     select HAVE_ARM_SCU
>>> >> +     select HAVE_ARM_TWD if SMP
>>> >> +     select ARM_ERRATA_720789
>>> >> +     select ARM_ERRATA_754322
>>> >> +     select ARM_ERRATA_764369
>>> >> +     select ARM_ERRATA_794072
>>> >> +     select PL310_ERRATA_588369
>>> >> +     select PL310_ERRATA_727915
>>> >> +     select USB_EHCI_ROOT_HUB_TT
>>> >> +     select USB_ARCH_HAS_HCD
>>> >> +     select USB_ARCH_HAS_EHCI
>>> >> +     select USB_EHCI_HCD
>>> >> +     select USB_ARCH_HAS_OHCI
>>> >> +     select USB_OHCI_HCD
>>> >> +     select USB
>>> >> +     select FIQ
>>> >> +     select CPU_USE_DOMAINS
>>> >> +     select GENERIC_CLOCKEVENTS
>>> >> +     select CLKDEV_LOOKUP
>>> >> +     select COMMON_CLK if OF
>>> >> +     select NPCM750_TIMER
>>> >> +     select MFD_SYSCON
>>> >> +     help
>>> >> +       Support for NPCM750 BMC CPU (Poleg).
>>> >> +
>>> >> +       Nuvoton NPCM750 BMC based on the Cortex A9.
>>> >> +
>>> >> +endif
>>> >> diff --git a/arch/arm/mach-npcm/Makefile b/arch/arm/mach-npcm/Makefile
>>> >> new file mode 100644
>>> >> index 000000000000..78416055b854
>>> >> --- /dev/null
>>> >> +++ b/arch/arm/mach-npcm/Makefile
>>> >> @@ -0,0 +1,3 @@
>>> >> +AFLAGS_headsmp.o             += -march=armv7-a
>>> >> +
>>> >> +obj-$(CONFIG_CPU_NPCM750)    += npcm7xx.o platsmp.o headsmp.o
>>> >> diff --git a/arch/arm/mach-npcm/headsmp.S b/arch/arm/mach-npcm/headsmp.S
>>> >> new file mode 100644
>>> >> index 000000000000..9fccbbd49ed4
>>> >> --- /dev/null
>>> >> +++ b/arch/arm/mach-npcm/headsmp.S
>>> >> @@ -0,0 +1,17 @@
>>> >> +/*
>>> >> + * Copyright 2017 Google, Inc.
>>> >> + *
>>> >> + * This program is free software; you can redistribute it and/or modify
>>> >> + * it under the terms of the GNU General Public License version 2 as
>>> >> + * published by the Free Software Foundation.
>>> >> + */
>>> >> +
>>> >> +#include <linux/linkage.h>
>>> >> +#include <linux/init.h>
>>> >> +#include <asm/assembler.h>
>>> >> +
>>> >> +ENTRY(npcm7xx_secondary_startup)
>>> >> +     safe_svcmode_maskall r0
>>> >> +
>>> >> +     b       secondary_startup
>>> >> +ENDPROC(npcm7xx_secondary_startup)
>>> >
>>> > Why do you need this?  The switch to svc mode is already handled by
>>> > secondary_startup.
>>>
>>> Florian Fainelli already brought this up:
>>> https://www.spinics.net/lists/arm-kernel/msg605126.html
>>> Without this the kernel complains that the core is started in
>>> "wrong/inconsistent mode":
>>
>> The solution would be a comment to indicate why it's necessary :)
>>
>>>
>>> SMP: Total of 2 processors activated (398.13 BogoMIPS).
>>> CPU: WARNING: CPU(s) started in wrong/inconsistent modes (primary CPU
>>> mode 0x13)
>>> CPU: This may indicate a broken bootloader or firmware.
>>>
>>> >
>>> >> diff --git a/arch/arm/mach-npcm/npcm7xx.c b/arch/arm/mach-npcm/npcm7xx.c
>>> >> new file mode 100644
>>> >> index 000000000000..132e9d587857
>>> >> --- /dev/null
>>> >> +++ b/arch/arm/mach-npcm/npcm7xx.c
>>> >> @@ -0,0 +1,34 @@
>>> >> +/*
>>> >> + * Copyright (c) 2017 Nuvoton Technology corporation.
>>> >> + * Copyright 2017 Google, Inc.
>>> >> + *
>>> >> + * This program is free software; you can redistribute it and/or modify
>>> >> + * it under the terms of the GNU General Public License version 2 as
>>> >> + * published by the Free Software Foundation.
>>> >> + */
>>> >> +
>>> >> +#include <linux/kernel.h>
>>> >> +#include <linux/types.h>
>>> >> +#include <asm/mach/arch.h>
>>> >> +#include <asm/mach-types.h>
>>> >> +#include <asm/mach/map.h>
>>> >> +#include <asm/hardware/cache-l2x0.h>
>>> >> +
>>> >> +#define NPCM7XX_AUX_VAL (L310_AUX_CTRL_INSTR_PREFETCH |                             \
>>> >> +                      L310_AUX_CTRL_DATA_PREFETCH |                         \
>>> >> +                      L310_AUX_CTRL_NS_LOCKDOWN |                           \
>>> >> +                      L310_AUX_CTRL_CACHE_REPLACE_RR |                      \
>>> >> +                      L2C_AUX_CTRL_SHARED_OVERRIDE |                        \
>>> >> +                      L310_AUX_CTRL_FULL_LINE_ZERO)
>>> >
>>> > Do you really need all these flags?
>>>
>>> Tomer, Avi, do we need these? I got this from the original version of
>>> the driver.
>>
>> The l2c driver manages L310_AUX_CTRL_FULL_LINE_ZERO itself, so you
>> shouldn't specify that.
>>
>> L2C_AUX_CTRL_SHARED_OVERRIDE is managed via the "arm,shared-override"
>> DT property, so you should use that in DT instead.
>>
>> Prefetching needs the prefetch control register configured to tune the
>> prefetching - that's platform specific so the l2c driver doesn't touch
>> it (it expects firmware to have configured it.)  If firmware needs to
>> configure that, it might as well configure the flags too as they're
>> shared into that very same register.  If not, I think the l2c prefetch
>> register defaults to a very small prefetch, and is probably not worth
>> setting the enable bits without configuring the depth of prefetch.
>
> Yes, we do it in the firmware.
>
>>
>> L310_AUX_CTRL_NS_LOCKDOWN is always enabled by the l2c driver, so
>> shouldn't be necessary.
>>
>> So that leaves only L310_AUX_CTRL_CACHE_REPLACE_RR.
>>
>
> You dont need to add L310_AUX_CTRL_CACHE_REPLACE_RR to the l2c aux value.
>
>>>
>>> >
>>> >> +
>>> >> +static const char *const npcm7xx_dt_match[] = {
>>> >> +     "nuvoton,npcm750",
>>> >> +     NULL
>>> >> +};
>>> >> +
>>> >> +DT_MACHINE_START(NPCM7XX_DT, "NPCMX50 Chip family")
>>> >> +     .atag_offset    = 0x100,
>>> >> +     .dt_compat      = npcm7xx_dt_match,
>>> >> +     .l2c_aux_val    = NPCM7XX_AUX_VAL,
>>> >> +     .l2c_aux_mask   = ~NPCM7XX_AUX_VAL,
>>> >> +MACHINE_END
>>> >> diff --git a/arch/arm/mach-npcm/platsmp.c b/arch/arm/mach-npcm/platsmp.c
>>> >> new file mode 100644
>>> >> index 000000000000..450e83c3c531
>>> >> --- /dev/null
>>> >> +++ b/arch/arm/mach-npcm/platsmp.c
>>> >> @@ -0,0 +1,88 @@
>>> >> +/*
>>> >> + * Copyright 2017 Google, Inc.
>>> >> + *
>>> >> + * This program is free software; you can redistribute it and/or modify
>>> >> + * it under the terms of the GNU General Public License version 2 as
>>> >> + * published by the Free Software Foundation.
>>> >> + */
>>> >> +
>>> >> +#define pr_fmt(fmt) "PLATSMP: " fmt
>>> >
>>> > Maybe something more descriptive?
>>> >
>>> >> +
>>> >> +#include <linux/delay.h>
>>> >> +#include <linux/device.h>
>>> >> +#include <linux/smp.h>
>>> >> +#include <linux/io.h>
>>> >> +#include <linux/of.h>
>>> >> +#include <linux/of_device.h>
>>> >> +#include <linux/of_platform.h>
>>> >> +#include <linux/of_address.h>
>>> >> +#include <asm/cacheflush.h>
>>> >> +#include <asm/smp.h>
>>> >> +#include <asm/smp_plat.h>
>>> >> +#include <asm/smp_scu.h>
>>> >> +
>>> >> +#define NPCM7XX_SCRPAD_REG 0x13c
>>> >> +
>>> >> +extern void npcm7xx_secondary_startup(void);
>>> >> +
>>> >> +static int npcm7xx_smp_boot_secondary(unsigned int cpu,
>>> >> +                                   struct task_struct *idle)
>>> >> +{
>>> >> +     struct device_node *gcr_np;
>>> >> +     void __iomem *gcr_base;
>>> >> +     int ret = 0;
>>> >> +
>>> >> +     gcr_np = of_find_compatible_node(NULL, NULL, "nuvoton,npcm750-gcr");
>>> >> +     if (!gcr_np) {
>>> >> +             pr_err("no gcr device node\n");
>>> >> +             ret = -EFAULT;
>>> >
>>> > EFAULT is used for bad userspace addresses, it should not be used for
>>> > other stuff - and a missing node is certainly not a "Bad address".
>>> >
>>> >> +             goto out;
>>> >> +     }
>>> >> +     gcr_base = of_iomap(gcr_np, 0);
>>> >> +     if (!gcr_base) {
>>> >> +             pr_err("could not iomap gcr at: 0x%p\n", gcr_base);
>>> >> +             ret = -EFAULT;
>>> >
>>> > This is more -ENOMEM.
>>> >
>>> >> +             goto out;
>>> >> +     }
>>> >> +
>>> >> +     /* give boot ROM kernel start address. */
>>> >> +     iowrite32(__pa_symbol(npcm7xx_secondary_startup), gcr_base +
>>> >> +               NPCM7XX_SCRPAD_REG);
>>> >> +     /* make sure npcm7xx_secondary_startup is seen by all observers. */
>>> >> +     smp_wmb();
>>> >
>>> > I think you mean "make sure the previous write is seen by all observers".
>>> > However, doesn't "dsb_sev()" already do that?
>>> >
>>> >> +     dsb_sev();
>>> >> +     /* make sure write buffer is drained */
>>> >> +     mb();
>>> >
>>> > This looks over the top.
>>> >
>>> >> +
>>> >> +     iounmap(gcr_base);
>>> >> +out:
>>> >> +     return ret;
>>> >> +}
>>> >> +
>>> >> +static void __init npcm7xx_smp_prepare_cpus(unsigned int max_cpus)
>>> >> +{
>>> >> +     struct device_node *scu_np;
>>> >> +     void __iomem *scu_base;
>>> >> +
>>> >> +     scu_np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
>>> >> +     if (!scu_np) {
>>> >> +             pr_err("no scu device node\n");
>>> >> +             return;
>>> >> +     }
>>> >> +     scu_base = of_iomap(scu_np, 0);
>>> >> +     if (!scu_base) {
>>> >> +             pr_err("could not iomap scu at: 0x%p\n", scu_base);
>>> >> +             return;
>>> >> +     }
>>> >> +
>>> >> +     scu_enable(scu_base);
>>> >> +
>>> >> +     iounmap(scu_base);
>>> >> +}
>>> >> +
>>> >> +static struct smp_operations npcm7xx_smp_ops __initdata = {
>>> >> +     .smp_prepare_cpus = npcm7xx_smp_prepare_cpus,
>>> >> +     .smp_boot_secondary = npcm7xx_smp_boot_secondary,
>>> >> +};
>>> >> +
>>> >> +CPU_METHOD_OF_DECLARE(npcm7xx_smp, "nuvoton,npcm7xx-smp", &npcm7xx_smp_ops);
>>> >> --
>>> >> 2.15.0.rc0.271.g36b669edcc-goog
>>> >>
>>> >
>>> > --
>>> > RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
>>> > FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up
>>> > According to speedtest.net: 8.21Mbps down 510kbps up
>>
>> --
>> RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
>> FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up
>> According to speedtest.net: 8.21Mbps down 510kbps up
>
> Thanks,
>
> Tomer