Re: [PATCH 6/8] pbl: fdt: add support to parse reserved mem

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 20.04.21 09:56, Rouven Czerwinski wrote:
> This allows the PBL to fill a reserved memory map which a subsequent
> commit will use modify the early MMU mapping.
> 
> Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
> ---
>  include/pbl.h | 15 ++++++++++
>  pbl/fdt.c     | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 95 insertions(+)
> 
> diff --git a/include/pbl.h b/include/pbl.h
> index 194d5e7508..df0f41ac5b 100644
> --- a/include/pbl.h
> +++ b/include/pbl.h
> @@ -34,4 +34,19 @@ ssize_t pbl_fat_load(struct pbl_bio *, const char *filename, void *dest, size_t
>  
>  void fdt_find_mem(const void *fdt, unsigned long *membase, unsigned long *memsize);
>  
> +struct pbl_reserved_memory {
> +	phys_addr_t			base;
> +	phys_addr_t			size;
> +	unsigned int			flag;

flags

> +};
> +
> +#define MAX_RESERVED_REGIONS	8
> +
> +#define FDT_RES_MEM_FLAG_NOMAP		BIT(0)
> +
> +void fdt_fill_reserve_mem(const void *fdt);
> +
> +struct pbl_reserved_memory* get_pbl_reserved_memory(void);
> +int get_pbl_reserved_memory_num(void);
> +
>  #endif /* __PBL_H__ */
> diff --git a/pbl/fdt.c b/pbl/fdt.c
> index b4a40a514b..f8e301843f 100644
> --- a/pbl/fdt.c
> +++ b/pbl/fdt.c
> @@ -68,3 +68,83 @@ err:
>  	pr_err("No memory, cannot continue\n");
>  	while (1);
>  }
> +
> +struct pbl_reserved_memory reserved_mem[MAX_RESERVED_REGIONS];
> +int reserved_mem_count;

Both can be made static.

> +
> +void fdt_fill_reserve_mem(const void *fdt)
> +{
> +	const __be32 *nap, *nsp, *reg;
> +	uint32_t na, ns;
> +	int node, size, i, parent;
> +	const void * prop;
> +	uint64_t memsize64, membase64;
> +	bool nomap;
> +
> +	/* Make sure FDT blob is sane */
> +	if (fdt_check_header(fdt) != 0) {
> +		pr_err("Invalid device tree blob\n");
> +		return;
> +	}
> +
> +	parent = fdt_path_offset(fdt, "/reserved-memory");
> +	if (parent < 0) {
> +		pr_info("Cannot find reserved-memory node\n");
> +		return;
> +	}
> +
> +	nap = fdt_getprop(fdt, parent, "#address-cells", &size);
> +	if (!nap || (size != 4)) {
> +		pr_err("Cannot find #address-cells property");
> +		return;
> +	}
> +	na = fdt32_to_cpu(*nap);

fdt_address_cells?

> +
> +	nsp = fdt_getprop(fdt, parent, "#size-cells", &size);
> +	if (!nsp || (size != 4)) {
> +		pr_err("Cannot find #size-cells property");
> +		return;
> +	}
> +	ns = fdt32_to_cpu(*nap);

fdt_size_cells?

> +
> +	fdt_for_each_subnode(node, fdt, parent) {
> +		nomap = true;
> +		reg = fdt_getprop(fdt, node, "reg", &size);
> +		if (size < (na + ns) * sizeof(u32)) {
> +			pr_err("cannot get memory range\n");
> +			return;
> +		}
> +
> +		membase64 = 0;
> +		for (i = 0; i < na; i++)
> +			membase64 = (membase64 << 32) | fdt32_to_cpu(*reg++);

I wondered whether there's a helper for that, but couldn't find anything.

> +
> +		/* get the memsize and truncate it to under 4G on 32 bit machines */
> +		memsize64 = 0;
> +		for (i = 0; i < ns; i++)
> +			memsize64 = (memsize64 << 32) | fdt32_to_cpu(*reg++);
> +
> +		prop = fdt_getprop(fdt, node, "nomap", NULL);
> +		if (!prop)
> +			nomap = false;
> +
> +		reserved_mem[reserved_mem_count].base = membase64;
> +		reserved_mem[reserved_mem_count].size = memsize64;
> +		if (nomap)
> +			reserved_mem[reserved_mem_count].flag |= FDT_RES_MEM_FLAG_NOMAP;
> +		reserved_mem_count++;
> +	}
> +
> +	if ((node < 0) && (node != -FDT_ERR_NOTFOUND)) {
> +		pr_err("Error while parsing reserved-memory nodes: %d\n", node);
> +		return;
> +	}
> +}
> +
> +struct pbl_reserved_memory* get_pbl_reserved_memory(void) {

{ on separate line, make it const.

> +	return (struct pbl_reserved_memory*)&reserved_mem;

just return reserved_mem; should work

> +}
> +
> +int get_pbl_reserved_memory_num(void) {

Ditto

> +	return reserved_mem_count;
> +}
> 

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