[U-Boot] [PATCH] Honor /memory/reg node in DTB files

[Marek Vasut]

Dear Deepak Saxena,

> commit 341764495180a712b9aaccfa0479b2ff7e44e35b
> Author: Deepak Saxena <deepak_saxena at mentor.com>
> Date:   Mon Dec 6 15:52:07 2010 -0800
> 
>      Honor /memory/reg node in DTB files
> 
>      This patch adds code to the bootm path to check if a valid
>      /memory/reg node exists in the DTB file and if so, it
>      does not override it with the values in bi_memstart and
>      bi_memsize. This is particularly useful in multi-core
>      environments where the memory may be partitioned across
>      a large number of nodes.
> 
>      While the same can be accomplished on certain boards (p1022ds
>      and p1_p2_rdb) by using the bootm_low and bootm_size
>      environment variables, that solution is not universal and
>      requires adding code ft_board_setup() for any new board
>      that wants to support AMP operation. Also, given that the
>      DTB is already  used to partition board devices (see commit
>      dc2e673 in the Linux kernel tree), it makes sense to
>      allow memory to be partitioned the same way from a user
>      configuration perspective.
> 
>      This patch allows for the user to override the DTB file parameters
>      on the p1022ds and p1_p2_rdb boards by setting the bootm_low and
>      bootm_size to something other than bi_memstart and bi_memsize.
>      In the long-term, those env variables should be depecrated and
>      removed and system implementors should provide the memory
>      partitioning information in the DTB.
> 
>      Signed-off-by: Deepak Saxena <deepak_saxena at mentor.com>
>      Signed-off-by: Hollis Blanchard <hollis_blanchard at mentor.com>
> 
> ---
> 
> See http://lists.denx.de/pipermail/u-boot/2010-December/083057.html
> for initial proposal on this.
> 
> diff --git a/arch/powerpc/cpu/mpc85xx/fdt.c
> b/arch/powerpc/cpu/mpc85xx/fdt.c index 4540364..6d384e3 100644
> --- a/arch/powerpc/cpu/mpc85xx/fdt.c
> +++ b/arch/powerpc/cpu/mpc85xx/fdt.c
> @@ -377,6 +377,55 @@ static void ft_fixup_qe_snum(void *blob)
>   }
>   #endif
> 
> +/*
> + * Check to see if an valid memory/reg property exists
> + * in the fdt. If so, we do not overwrite it with what's
> + * been scanned.
> + *
> + * Valid mean all the following:
> + *
> + * - Memory node has a device-type of "memory"
> + * - A reg property exists which:
> + *   + has exactly as many cells as #address-cells + #size-cells
> + *   + provides a range that is within [bi_memstart, bi_memstart +
> bi_memsize]
> + */
> +static int ft_validate_memory(void *blob, bd_t *bd)
> +{
> +	int nodeoffset;
> +	u32 *addrcell = (u32*)fdt_getprop(blob, 0, "#address-cells", NULL);
> +	u32 *sizecell = (u32*)fdt_getprop(blob, 0, "#size-cells", NULL);
> +	u64 reg_base, reg_size;
> +	void *reg, *dtype;
> +	int len;
> +
> +	if ((nodeoffset = fdt_path_offset(blob, "/memory")) >= 0)
> +	{
> +		dtype = fdt_getprop(blob, nodeoffset, "device_type", &len);
> +		if (!dtype || (strcmp(dtype, "memory") != 0))
> +			return 0;
> +
> +		reg = fdt_getprop(blob, nodeoffset, "reg", &len);
> +		if (reg && len == ((*addrcell + *sizecell) * 4)) {
> +			if (*addrcell == 2) {
> +				reg_base = ((u64*)reg)[0];
> +				reg_size = ((u64*)reg)[1];
> +			} else {
> +				reg_base = ((u32*)reg)[0];
> +				reg_size = ((u32*)reg)[1];
> +			}
> +
> +			if ((reg_size) &&
> +			    (reg_base >= (u64)bd->bi_memstart) &&
> +			    ((reg_size + reg_base)
> +			     <= ((u64)bd->bi_memstart + (u64)bd->bi_memsize)))
> +				return 1;
> +		}
> +	}
> +
> +	return 0;
> +
> +}
> +
>   void ft_cpu_setup(void *blob, bd_t *bd)
>   {
>   	int off;
> @@ -434,7 +483,8 @@ void ft_cpu_setup(void *blob, bd_t *bd)
>   		"clock-frequency", CONFIG_SYS_CLK_FREQ, 1);
>   #endif
> 
> -	fdt_fixup_memory(blob, (u64)bd->bi_memstart, (u64)bd->bi_memsize);
> +	if (!ft_validate_memory(blob, bd))
> +		fdt_fixup_memory(blob, (u64)bd->bi_memstart, (u64)bd-
>bi_memsize);
> 
>   #ifdef CONFIG_MP
>   	ft_fixup_cpu(blob, (u64)bd->bi_memstart + (u64)bd->bi_memsize);
> diff --git a/board/freescale/p1022ds/p1022ds.c
> b/board/freescale/p1022ds/p1022ds.c
> index 5cdee9f..7378d88 100644
> --- a/board/freescale/p1022ds/p1022ds.c
> +++ b/board/freescale/p1022ds/p1022ds.c
> @@ -320,7 +320,8 @@ void ft_board_setup(void *blob, bd_t *bd)
>   	base = getenv_bootm_low();
>   	size = getenv_bootm_size();
> 
> -	fdt_fixup_memory(blob, (u64)base, (u64)size);
> +	if (base != (phys_addr_t)bd->bi_memstart && size !=
> (phys_addr_t)bd->bi_memsize)
> +		fdt_fixup_memory(blob, (u64)base, (u64)size);
> 
>   	FT_FSL_PCI_SETUP;
> 
> diff --git a/board/freescale/p1_p2_rdb/p1_p2_rdb.c
> b/board/freescale/p1_p2_rdb/p1_p2_rdb.c
> index fae31f2..5e4adc6 100644
> --- a/board/freescale/p1_p2_rdb/p1_p2_rdb.c
> +++ b/board/freescale/p1_p2_rdb/p1_p2_rdb.c
> @@ -220,9 +220,10 @@ void ft_board_setup(void *blob, bd_t *bd)
>   	base = getenv_bootm_low();
>   	size = getenv_bootm_size();
> 
> -	ft_pci_board_setup(blob);
> +	if (base != (phys_addr_t)bd->bi_memstart && size !=
> (phys_addr_t)bd->bi_memsize)
> +		fdt_fixup_memory(blob, (u64)base, (u64)size);
> 
> -	fdt_fixup_memory(blob, (u64)base, (u64)size);
> +	ft_pci_board_setup(blob);
>   }
>   #endif
> 
What was the conclusion on this patch ?