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

Marek Vasut
2012-03-31T19:32:41Z

Dear Deepak Saxena,

> commit 341764495180a712b9aaccfa0479b2ff7e44e35b
> Author: Deepak Saxena <deepak_saxena@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@mentor.com>
> Signed-off-by: Hollis Blanchard <hollis_blanchard@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 ?