Re: [PATCH RESEND 1/5] ARM: BCM63XX: add basic support for the Broadcom BCM63138 DSL SoC

Arnd Bergmann
2014-04-22T10:45:52Z

On Monday 21 April 2014 18:39:14 Florian Fainelli wrote:
> This patch adds basic support for the Broadcom BCM63138 DSL SoC which is
> using a dual-core Cortex A9 system. Add the very minimum required code
> boot Linux on this SoC.
>
> Due to the two specific register address spaces located at 0x8000_0000
> and 0xfffe_0000, we need to setup a specific iotable descriptor for
> those to be remapped at the expected virtual addresses.

What is the significance of the "expected virtual address"? All drivers
nowadays should call ioremap() and use whatever virtual address comes
out of that.

> Finally, the PL310 cache controller requires a bit of tweaking before
> handing its initialization over l2x0_of_init(), this is also taken care
> of to make sure that its size is properly configured.

Russell has just spent a lot of work on cleaning up the l2x0 setup
of various platforms. I really don't want to see new platform specific
code for this.

> diff --git a/arch/arm/mach-bcm/Kconfig b/arch/arm/mach-bcm/Kconfig
> index 49c914cd9c7a..26b51bcf878c 100644
> --- a/arch/arm/mach-bcm/Kconfig
> +++ b/arch/arm/mach-bcm/Kconfig
> @@ -69,6 +69,26 @@ config ARCH_BCM_5301X
> different SoC or with the older BCM47XX and BCM53XX based
> network SoC using a MIPS CPU, they are supported by arch/mips/bcm47xx
>
> +config ARCH_BCM_63XX
> + bool "Broadcom BCM63xx DSL SoC" if ARCH_MULTI_V7
> + depends on MMU
> + select ARM_ERRATA_754322
> + select ARM_ERRATA_764369 if SMP
> + select ARM_GIC
> + select ARM_GLOBAL_TIMER
> + select CACHE_L2X0
> + select COMMON_CLK
> + select CPU_V7
> + select GENERIC_CLOCKEVENTS
> + select HAVE_ARM_ARCH_TIMER
> + select HAVE_ARM_TWD if SMP
> + select HAVE_ARM_SCU if SMP
> + select HAVE_SMP

A lot of these are already selected by ARCH_MULTI_V7 and can be
omitted here.

> +#ifndef __ARM_BCM63XX_H
> +#define __ARM_BCM63XX_H
> +
> +#define IO_ADDRESS(x) (((x) & 0x00ffffff) + 0xfc000000)
> +
> +/* AHB register space */
> +#define BCM63XX_AHB_PHYS 0x80001000
> +#define BCM63XX_AHB_VIRT IO_ADDRESS(BCM63XX_AHB_PHYS)
> +#define BCM63XX_AHB_SIZE 0x800000
> +
> +/* PERIPH (legacy) register space */
> +#define BCM63XX_PERIPH_PHYS 0xfffe8000
> +#define BCM63XX_PERIPH_VIRT IO_ADDRESS(BCM63XX_PERIPH_PHYS)
> +#define BCM63XX_PERIPH_SIZE 0x10000

You shouldn't need these any more. If you do, just move all of this
into the main file, to ensure no other file accidentally relies
on hardcoded values.

Note that BCM63XX_AHB_PHYS is nor aligned, so AFAICT you don't
actually get a huge page entry for it, and there is no point
doing this at all, as it has neither functional nor performance
relevance.

You may have out-of-tree drivers that you haven't cleaned up
or posted yet relying on specific static mappings, but that is
no reason to have these mappings in the mainline kernel.

> diff --git a/arch/arm/mach-bcm/board_bcm63xx.c b/arch/arm/mach-bcm/board_bcm63xx.c
> new file mode 100644
> index 000000000000..a779aca673c4
> --- /dev/null
> +++ b/arch/arm/mach-bcm/board_bcm63xx.c

Maybe just "bcm63xx.c"? We don't really do "board" files any more.

> +static void __init bcm63xx_l2cc_init(void)
> +{
> + u32 auxctl_val = 0, auxctl_msk = ~0UL;
> +
> + /* 16-way cache */
> + auxctl_val |= (1 << L2X0_AUX_CTRL_ASSOCIATIVITY_SHIFT);
> + auxctl_msk &= ~(1 << L2X0_AUX_CTRL_ASSOCIATIVITY_SHIFT);
> + /* 32 KB */
> + auxctl_val |= (2 << L2X0_AUX_CTRL_WAY_SIZE_SHIFT);
> + auxctl_msk &= ~(L2X0_AUX_CTRL_WAY_SIZE_MASK);
> +
> + /*
> + * Set bit 22 in the auxiliary control register. If this bit
> + * is cleared, PL310 treats Normal Shared Non-cacheable
> + * accesses as Cacheable no-allocate.
> + */
> + auxctl_val |= (1 << L2X0_AUX_CTRL_SHARE_OVERRIDE_SHIFT);
> +
> + /* Allow non-secure access */
> + auxctl_val |= (1 << L2X0_AUX_CTRL_NS_INT_CTRL_SHIFT);
> + /* Instruction prefetch */
> + auxctl_val |= (1 << L2X0_AUX_CTRL_INSTR_PREFETCH_SHIFT);
> + /* Early BRESP */
> + auxctl_val |= (1 << L2X0_AUX_CTRL_EARLY_BRESP_SHIFT);
> +
> + l2x0_of_init(auxctl_val, auxctl_msk);
> +}

What are the power-on values of bits you override here? Are you sure
you have to force all of them?

Don't we already have ways to specify the same things in DT properties?

Arnd