[PATCH v3] riscv: spacemit: k1: probe dram size during boot phase.

[Huan Zhou]

On Tue, Jan 14, 2025 at 04:01:25PM +0800, Huan Zhou wrote:
> Implement functionality to probe and calculate the DRAM size during the boot phase for the RISC-V spacemit K1 platform.
> The `map_format_size` function extracts the memory density from a given value, while `ddr_get_density` aggregates the sizes of the memory chips.
> The `dram_init` function initializes the global RAM base and size based on the detected DRAM density, ensuring proper memory configuration at boot.
> 
This commit message is a little bit too long, will be fixed in next version :(
> Tested-by: Marcel Ziswiler <marcel at ziswiler.com> # BPI-F3 16G
> Signed-off-by: Huan Zhou <me at per1cycle.org>
> ---
> This patch introduce improvement for get dram size on spacemit k1 platform,
> retrieving the dram size dynamically.
> Have tested on Licheepi LPI3A 8G[1].
> 
> Links:
> [1] https://gist.github.com/per1cycle/e4eab66ebb6f83fe5118e823367fce28 .
> 
> Changes in v3:
> - Remove the inline attr in arch/riscv/cpu/k1/dram.c map_format_size().
> - Add detailed commit message.
> - Link to v2: https://lore.kernel.org/r/20250114-get-dram-size-v2-1-aba5a281ea28@per1cycle.org
> 
> Changes in v2:
> - Fix bracker and return type in map_format_size() function.
> - Add test log in the cover letter..
> - Link to v1: https://lore.kernel.org/r/20250108-get-dram-size-v1-1-4bae32ecf756@per1cycle.org
> ---
>  arch/riscv/cpu/k1/dram.c | 40 ++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 38 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/riscv/cpu/k1/dram.c b/arch/riscv/cpu/k1/dram.c
> index c477c15cbfb19f0e3a0ee72985b602f5bda352d7..54d209ca277db7b304df04f81b12ae4efa400e45 100644
> --- a/arch/riscv/cpu/k1/dram.c
> +++ b/arch/riscv/cpu/k1/dram.c
> @@ -4,17 +4,53 @@
>   */
>  
>  #include <asm/global_data.h>
> +#include <asm/io.h>
>  #include <config.h>
> +#include <bitfield.h>
>  #include <fdt_support.h>
>  #include <linux/sizes.h>
>  
> +#define DDR_BASE 0xC0000000
>  DECLARE_GLOBAL_DATA_PTR;
>  
> +static phys_size_t map_format_size(u32 val)
also this part will be rename more properly.
> +{
> +	u32 tmp;
> +
> +	if (!(val & 0x1))
> +		return 0;
> +
> +	tmp = bitfield_extract(val, 16, 5);
> +	switch (tmp) {
> +	case 0xd:
> +		return 512;
> +	case 0xe:
> +		return 1024;
> +	case 0xf:
> +		return 2048;
> +	case 0x10:
> +		return 4096;
> +	case 0x11:
> +		return 8192;
> +	default:
> +		pr_info("Invalid DRAM density %x\n", val);
> +		return 0;
> +	}
> +}
> +
> +phys_size_t ddr_get_density(void)
> +{
> +	phys_size_t cs0_size = map_format_size(readl((void *)DDR_BASE + 0x200));
> +	phys_size_t cs1_size = map_format_size(readl((void *)DDR_BASE + 0x208));
> +	phys_size_t ddr_size = cs0_size + cs1_size;
> +
> +	return ddr_size;
> +}
> +
>  int dram_init(void)
>  {
>  	gd->ram_base = CFG_SYS_SDRAM_BASE;
> -	/* TODO get ram size from ddr controller */
> -	gd->ram_size = SZ_4G;
> +	gd->ram_size = ddr_get_density() * SZ_1M;
>  	return 0;
>  }
>  
> 
> ---
> base-commit: 19fc0b7f7d907119a13e9c207991899f0817f8fc
> change-id: 20250108-get-dram-size-65cf59a15201
> 
> Best regards,
> -- 
> Huan Zhou <me at per1cycle.org>
>