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Message-ID: <54352DAC.3080001@broadcom.com>
Date: Wed, 8 Oct 2014 05:27:24 -0700
From: Scott Branden <sbranden@...adcom.com>
To: Arnd Bergmann <arnd@...db.de>,
<linux-arm-kernel@...ts.infradead.org>
CC: Christian Daudt <bcm@...thebug.org>,
Matt Porter <mporter@...aro.org>,
Russell King <linux@....linux.org.uk>,
<bcm-kernel-feedback-list@...adcom.com>,
Mike Turquette <mturquette@...aro.org>,
Alex Elder <elder@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
"Kumar Gala" <galak@...eaurora.org>,
Andrew Morton <akpm@...ux-foundation.org>,
"David S. Miller" <davem@...emloft.net>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Joe Perches <joe@...ches.com>,
"Mauro Carvalho Chehab" <m.chehab@...sung.com>,
Antti Palosaari <crope@....fi>, <devicetree@...r.kernel.org>,
Ray Jui <rjui@...adcom.com>, <linux-kernel@...r.kernel.org>,
Jonathan Richardson <jonathar@...adcom.com>,
JD Zheng <jdzheng@...adcom.com>
Subject: Re: [PATCH 1/6] ARM: cygnus: Initial support for Broadcom Cygnus
SoC
Thanks for the review - comments inline.
On 14-10-08 12:54 AM, Arnd Bergmann wrote:
> On Tuesday 07 October 2014 22:27:00 Scott Branden wrote:
>> From: Jonathan Richardson <jonathar@...adcom.com>
>>
>> Adds initial support for the Cygnus SoC based on Broadcom’s iProc series.
>>
>> Reviewed-by: Ray Jui <rjui@...adcom.com>
>> Reviewed-by: Desmond Liu <desmondl@...adcom.com>
>> Reviewed-by: JD (Jiandong) Zheng <jdzheng@...adcom.com>
>> Tested-by: Jonathan Richardson <jonathar@...adcom.com>
>> Signed-off-by: Scott Branden <sbranden@...adcom.com>
>> ---
>> arch/arm/mach-bcm/Kconfig | 31 ++++++++
>> arch/arm/mach-bcm/Makefile | 3 +
>> arch/arm/mach-bcm/bcm_cygnus.c | 166 ++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 200 insertions(+)
>> create mode 100644 arch/arm/mach-bcm/bcm_cygnus.c
>>
>> diff --git a/arch/arm/mach-bcm/Kconfig b/arch/arm/mach-bcm/Kconfig
>> index fc93800..2dd3f78 100644
>> --- a/arch/arm/mach-bcm/Kconfig
>> +++ b/arch/arm/mach-bcm/Kconfig
>> @@ -5,6 +5,37 @@ menuconfig ARCH_BCM
>>
>> if ARCH_BCM
>>
>> +config ARCH_BCM_IPROC
>> + bool "Broadcom ARMv7 iProc boards" if ARCH_MULTI_V7
>> + select ARM_GIC
>> + select CACHE_L2X0
>> + select HAVE_ARM_TWD if LOCAL_TIMERS
>> + select HAVE_CLK
>> + select CLKSRC_OF
>> + select CLKSRC_MMIO
>> + select GENERIC_CLOCKEVENTS
>> + select ARM_GLOBAL_TIMER
>> + select ARCH_REQUIRE_GPIOLIB
>> + select ARM_AMBA
>> + select PINCTRL
>> + select DEBUG_UART_8250
>
> A lot of these are implied by ARCH_MULTI_V7, just drop them here.
>
> Some others like DEBUG_UART_8250 should remain user-selectable, if
> the platform works without them.
>
Will review. It looks like DEBUG_UART_8250 actually has to move to
Kconfig.debug as that is where everyone else selects it.
>> + help
>> + This enables support for systems based on Broadcom IPROC architected SoCs.
>> + The IPROC complex contains one or more ARM CPUs along with common
>> + core periperals. Application specific SoCs are created by adding a
>> + uArchitecture containing peripherals outside of the IPROC complex.
>> + Currently supported SoCs are Cygnus.
>> +
>> +menu "iProc SoC based Machine types"
>> + depends on ARCH_BCM_IPROC
>> +
>> + config ARCH_BCM_CYGNUS
>> + bool "Support Broadcom Cygnus board"
>> + select USB_ARCH_HAS_EHCI if USB_SUPPORT
>> + help
>> + Support for Broadcom Cygnus SoC.
>> +endmenu
>
> I don't think you need per-board config options. The main option
> above should be enough.
This is not a per-board config option. This is actually a per-SoC
uArchtecture selection. More major uArchectures will be added to the
IPROC. Will Change comment to "Support Broadcom Cygnus SoC"
>
>> +
>> +#define CRMU_MAIL_BOX1 0x03024028
>> +#define CRMU_SOFT_RESET_CMD 0xFFFFFFFF
>
> Never hardcode physical register locations in source. This should come
> from DT, and get moved into a regular 'reset' device driver.
>
> You probably want to use drivers/power/reset/syscon-reboot.c
>
OK, thanks for advice on where to put reset device driver. Will
investigate.
>> +/* CRU_RESET register */
>> +static void * __iomem crmu_mail_box1_reg;
>> +
>> +#ifdef CONFIG_NEON
>> +
>> +#define CRU_BASE 0x1800e000
>> +#define CRU_SIZE 0x34
>> +#define CRU_CONTROL_OFFSET 0x0
>> +#define CRU_PWRDWN_EN_OFFSET 0x4
>> +#define CRU_PWRDWN_STATUS_OFFSET 0x8
>> +#define CRU_NEON0_HW_RESET 6
>> +#define CRU_CLAMP_ON_NEON0 20
>> +#define CRU_PWRONIN_NEON0 21
>> +#define CRU_PWRONOUT_NEON0 21
>> +#define CRU_PWROKIN_NEON0 22
>> +#define CRU_PWROKOUT_NEON0 22
>> +#define CRU_STATUS_DELAY_NS 500
>> +#define CRU_MAX_RETRY_COUNT 10
>> +#define CRU_RETRY_INTVL_US 1
>> +
>> +/* Power up the NEON/VFPv3 block. */
>> +static void bcm_cygnus_powerup_neon(void)
>> +{
>> + void * __iomem cru_base = ioremap(CRU_BASE, CRU_SIZE);
>> + u32 reg, i;
>
> Same thing here: this should really use the device node for CRU.
>
> Can you describe what the CRU is? Is this specific to NEON or is
> it some general-purpose power management unit?
>
It's a central resource unit with a lot of random registers to perform
various operations. To reduce confusion I'll probably move this out of
the kernel init and into the bootloader. This will simplify the kernel
init.
>> +static void __init bcm_cygnus_init(void)
>> +{
>> + of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
>> +
>> + l2x0_of_init(0, ~0UL);
>
> The l2x0_of_init can be removed now, just move the arguments into the
> respective fields of the machine descriptor.
>
Yes, thanks for pointing this out.
>> + crmu_mail_box1_reg = ioremap(CRMU_MAIL_BOX1, SZ_4);
>> + WARN_ON(!crmu_mail_box1_reg);
>> +
>> +#ifdef CONFIG_NEON
>> + bcm_cygnus_powerup_neon();
>> +#endif
>> +}
>
> In general, try to avoid #ifdef, use
>
> if (IS_ENABLED(CONFIG_NEON))
> bcm_cygnus_powerup_neon();
>
> instead.
>
>> +
>> +static const char const *bcm_cygnus_dt_compat[] = {
>> + "brcm,cygnus",
>> + NULL,
>> +};
>> +
>> +DT_MACHINE_START(BCM_CYGNUS_DT, "Broadcom Cygnus SoC")
>> + .init_machine = bcm_cygnus_init,
>> + .map_io = debug_ll_io_init,
>> + .dt_compat = bcm_cygnus_dt_compat,
>> + .restart = bcm_cygnus_restart
>> +MACHINE_END
>
> The map_io pointer is unnecessary, and the restart pointer should get
> set by the reset driver. I hope we can find a way to avoid the
> bcm_cygnus_init callback as well.
bcm_cygnus_init callback can be removed by moving initialization to
bootloader.
>
> Arnd
>
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