[PATCH 3/5] sunxi: move early "SRAM setup" into separate file

[Samuel Holland]

On 1/24/22 7:15 PM, Andre Przywara wrote:
> Currently we do some magic "SRAM setup" MMIO writes in s_init(), copied
> from the original BSP U-Boot. The comment speaks of this being required
> before DRAM access gets enabled, but there is no indication that this
> would actually be required that early.
> 
> Move this out of s_init(), into board_init_f(). Since this actually only
> affects a very few older SoCs, the actual code goes into the cpu/armv7
> directory, to move it out of the way for all other SoCs.
> 
> This also uses the opportunity to convert some #ifdefs over to the fancy
> IS_ENABLED() macros used in actual C code.
> 
> We keep the s_init() stub around for now, since armv8's lowlevel_init
> still relies on it.
> 
> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
> ---
>  arch/arm/cpu/armv7/sunxi/Makefile |  3 +++
>  arch/arm/cpu/armv7/sunxi/sram.c   | 45 +++++++++++++++++++++++++++++++
>  arch/arm/mach-sunxi/board.c       | 38 +++++---------------------
>  3 files changed, 54 insertions(+), 32 deletions(-)
>  create mode 100644 arch/arm/cpu/armv7/sunxi/sram.c
> 
> diff --git a/arch/arm/cpu/armv7/sunxi/Makefile b/arch/arm/cpu/armv7/sunxi/Makefile
> index 1d40d6a18dc..ad11be78632 100644
> --- a/arch/arm/cpu/armv7/sunxi/Makefile
> +++ b/arch/arm/cpu/armv7/sunxi/Makefile
> @@ -10,6 +10,9 @@ obj-y	+= timer.o
>  obj-$(CONFIG_MACH_SUN6I)	+= tzpc.o
>  obj-$(CONFIG_MACH_SUN8I_H3)	+= tzpc.o
>  
> +obj-$(CONFIG_MACH_SUN6I)	+= sram.o
> +obj-$(CONFIG_MACH_SUN8I)	+= sram.o
> +
>  ifndef CONFIG_SPL_BUILD
>  obj-$(CONFIG_ARMV7_PSCI)	+= psci.o
>  endif
> diff --git a/arch/arm/cpu/armv7/sunxi/sram.c b/arch/arm/cpu/armv7/sunxi/sram.c
> new file mode 100644
> index 00000000000..19395cce17c
> --- /dev/null
> +++ b/arch/arm/cpu/armv7/sunxi/sram.c
> @@ -0,0 +1,45 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * (C) Copyright 2012 Henrik Nordstrom <henrik at henriknordstrom.net>
> + *
> + * (C) Copyright 2007-2011
> + * Allwinner Technology Co., Ltd. <www.allwinnertech.com>
> + * Tom Cubie <tangliang at allwinnertech.com>
> + *
> + * SRAM init for older sunxi SoCs.
> + */
> +
> +#include <common.h>
> +#include <init.h>
> +#include <asm/io.h>
> +
> +void sunxi_sram_init(void)
> +{
> +	/*
> +	 * Undocumented magic taken from boot0, without this DRAM
> +	 * access gets messed up (seems cache related).
> +	 * The boot0 sources describe this as: "config ema for cache sram"
> +	 * Newer SoCs (A83T, H3 and anything beyond) don't need this anymore.
> +	 */
> +	if (IS_ENABLED(CONFIG_MACH_SUN6I))
> +		setbits_le32(SUNXI_SRAMC_BASE + 0x44, 0x1800);
> +
> +	if (IS_ENABLED(CONFIG_MACH_SUN8I)) {
> +		uint version;
> +
> +		/* Unlock sram version info reg, read it, relock */
> +		setbits_le32(SUNXI_SRAMC_BASE + 0x24, (1 << 15));
> +		version = readl(SUNXI_SRAMC_BASE + 0x24) >> 16;
> +		clrbits_le32(SUNXI_SRAMC_BASE + 0x24, (1 << 15));

This is an open-coded version of sunxi_get_sram_id().

> +
> +		if (IS_ENABLED(CONFIG_MACH_SUN8I_A23)) {
> +			if (version == 0x1650)
> +				setbits_le32(SUNXI_SRAMC_BASE + 0x44, 0x1800);
> +			else /* 0x1661 ? */
> +				setbits_le32(SUNXI_SRAMC_BASE + 0x44, 0xc0);
> +		} else if (IS_ENABLED(CONFIG_MACH_SUN8I_A33)) {
> +			if (version != 0x1667)
> +				setbits_le32(SUNXI_SRAMC_BASE + 0x44, 0xc0);
> +		}
> +	}
> +}
> diff --git a/arch/arm/mach-sunxi/board.c b/arch/arm/mach-sunxi/board.c
> index 8667ddf58e3..42ec02d96e3 100644
> --- a/arch/arm/mach-sunxi/board.c
> +++ b/arch/arm/mach-sunxi/board.c
> @@ -186,38 +186,6 @@ SPL_LOAD_IMAGE_METHOD("FEL", 0, BOOT_DEVICE_BOARD, spl_board_load_image);
>  
>  void s_init(void)
>  {
> -	/*
> -	 * Undocumented magic taken from boot0, without this DRAM
> -	 * access gets messed up (seems cache related).
> -	 * The boot0 sources describe this as: "config ema for cache sram"
> -	 */
> -#if defined CONFIG_MACH_SUN6I
> -	setbits_le32(SUNXI_SRAMC_BASE + 0x44, 0x1800);
> -#elif defined CONFIG_MACH_SUN8I
> -	__maybe_unused uint version;
> -
> -	/* Unlock sram version info reg, read it, relock */
> -	setbits_le32(SUNXI_SRAMC_BASE + 0x24, (1 << 15));
> -	version = readl(SUNXI_SRAMC_BASE + 0x24) >> 16;
> -	clrbits_le32(SUNXI_SRAMC_BASE + 0x24, (1 << 15));
> -
> -	/*
> -	 * Ideally this would be a switch case, but we do not know exactly
> -	 * which versions there are and which version needs which settings,
> -	 * so reproduce the per SoC code from the BSP.
> -	 */
> -#if defined CONFIG_MACH_SUN8I_A23
> -	if (version == 0x1650)
> -		setbits_le32(SUNXI_SRAMC_BASE + 0x44, 0x1800);
> -	else /* 0x1661 ? */
> -		setbits_le32(SUNXI_SRAMC_BASE + 0x44, 0xc0);
> -#elif defined CONFIG_MACH_SUN8I_A33
> -	if (version != 0x1667)
> -		setbits_le32(SUNXI_SRAMC_BASE + 0x44, 0xc0);
> -#endif
> -	/* A83T BSP never modifies SUNXI_SRAMC_BASE + 0x44 */
> -	/* No H3 BSP, boot0 seems to not modify SUNXI_SRAMC_BASE + 0x44 */
> -#endif
>  }
>  
>  #define SUNXI_INVALID_BOOT_SOURCE	-1
> @@ -312,8 +280,14 @@ u32 spl_boot_device(void)
>  	return sunxi_get_boot_device();
>  }
>  
> +__weak void sunxi_sram_init(void)
> +{
> +}

In configurations other than MACH_SUN6/8I, the strong definition of
sunxi_sram_init() is also an empty function, so this is no more efficient than
unconditionally compiling sram.c.

> +
>  void board_init_f(ulong dummy)
>  {
> +	sunxi_sram_init();
> +
>  #if defined CONFIG_MACH_SUN6I || defined CONFIG_MACH_SUN8I_H3
>  	/* Enable non-secure access to some peripherals */
>  	tzpc_init();
>