On Thu, Dec 30, 2010 at 12:38:00AM +0100, Walter Goossens wrote:
> This patch adds address translations to fdt. Needed when the early
> console is connected to a simple-bus that has address translation
> enabled.
>
> To be honest, I'm not too happy about this solution but it works and
> most code is stolen from other parts of the fdt code, so I'm
> probably not doing too weird stuff :)
> What do you guys think of this?
Hi Walter,
Thanks for the patch, comments below.
g.
>
> Greetz Walter
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index c1360e0..d586efe 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -538,6 +538,161 @@ int __init early_init_dt_scan_chosen(unsigned long
> node, const char *uname,
> /* break now */
> return 1;
> }
> +/**
> + * flat_dt_translate_address - Translate an address using the ranges property
> + *
> + * This function converts address from "node address-space" to "parent
> address-
> + * space"
> + */
> +static int __init flat_dt_translate_address(unsigned long node, unsigned
> long parent, u64 *address)
> +{
> + unsigned long size = 0;
> + __be32 *prop;
> + __be32 *ranges;
> + int size_cells = 0;
> + int addr_cells = 0;
> + int paddr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
> +
> + ranges = (u32 *)of_get_flat_dt_prop(node,"ranges",&size);
Shouldn't need the cast here. Also coding style. Need spaced after each ','
Lots of other style issues through this patch. You should run this
patch through scripts/checkpatch.pl before resubmitting.
> +
> + if(size==0) {
Coding style:
if (size == 0) {
> + pr_debug("No translation possible/necessary\n");
These are two different cases. If ranges is *not* present, then the
address cannot be translated and it looks like -EINVAL should be
returned. If ranges is empty, then the node address is 1:1 mapped to
the parent address and success should be returned.
> + return 0;
> + }
> +
> + prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
> + if (prop)
> + size_cells = be32_to_cpup(prop);
I'd reverse the logic:
prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
if (!prop)
return -EINVAL;
size_cells = be32_to_cpup(prop);
> + pr_debug("size_cells = %x\n", size_cells);
> +
> + prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
> + if (prop)
> + addr_cells = be32_to_cpup(prop);
Ditto here.
Also, before I dig too deep into the implementation, have you looked
at dt_xlate() in arch/powerpc/boot/devtree.c? It would need a bit of
rework, but it is essentially the algorithm you want to implement.
> + pr_debug("addr_cells = %x\n", addr_cells);
> +
> + if(parent) {
> + prop = of_get_flat_dt_prop(parent, "#address-cells", NULL);
> + if (prop)
> + paddr_cells = be32_to_cpup(prop);
> + pr_debug("paddr_cells = %x\n", paddr_cells);
> + }
> + if((addr_cells<=0)||(size_cells<=0)||
> + (addr_cells>2)||(size_cells>2)||(paddr_cells>2)) {
> + pr_warn("Translation not possible in fdt. Invalid address.\n");
> + *address = 0;
> + return -1;
> + }
> + pr_debug("FDT-Ranges:\n");
> + while(size>0) {
> + u64 from,to,tsize;
> + from = be32_to_cpup(ranges++);
> + size-=4;
> + if(addr_cells==2) {
> + from += (((u64)be32_to_cpup(ranges++))<<32);
> + size-=4;
> + }
> + to = be32_to_cpup(ranges++);
> + size-=4;
> + if(paddr_cells==2) {
> + to += (((u64)be32_to_cpup(ranges++))<<32);
> + size-=4;
> + }
> + tsize = be32_to_cpup(ranges++);
> + size-=4;
> + if(size_cells==2) {
> + tsize += (((u64)be32_to_cpup(ranges++))<<32);
> + size-=4;
> + }
> + pr_debug(" From %llX To %llX Size %llX\n", from, to, tsize);
> + if((*address>=from)&&(*address<(from+tsize)))
> + *address += (to - from);
> + }
> + return 1;
> +}
> +
> +static int __init of_scan_flat_dt_ranges(unsigned long *pnode,
> + unsigned long parent, unsigned long target,
> + u64 *address, int ignore)
> +{
> + int rc = 0;
> + int depth = -1;
> + char *pathp;
> + unsigned long p = *pnode;
> + do {
> + u32 tag = be32_to_cpup((__be32 *)p);
> +
> + p += 4;
> + if (tag == OF_DT_END_NODE) {
> + if(depth--) {
> + break;
> + } else {
> + continue;
> + }
> + }
> + if (tag == OF_DT_NOP)
> + continue;
> + if (tag == OF_DT_END)
> + break;
> + if (tag == OF_DT_PROP) {
> + u32 sz = be32_to_cpup((__be32 *)p);
> + p += 8;
> + if (be32_to_cpu(initial_boot_params->version) < 0x10)
> + p = ALIGN(p, sz >= 8 ? 8 : 4);
> + p += sz;
> + p = ALIGN(p, 4);
> + continue;
> + }
> + if (tag != OF_DT_BEGIN_NODE) {
> + pr_err("Invalid tag %x in flat device tree!\n", tag);
> + return -EINVAL;
> + }
> + pathp = (char *)p;
> + p = ALIGN(p + strlen(pathp) + 1, 4);
> + if ((*pathp) == '/') {
> + char *lp, *np;
> + for (lp = NULL, np = pathp; *np; np++)
> + if ((*np) == '/')
> + lp = np+1;
> + if (lp != NULL)
> + pathp = lp;
> + }
> + if((ignore==0) && (p == target)) {
> + rc = 1;
> + ignore++;
> + pr_debug("Found target. Start address translation\n");
> + }
> + if(depth) {
> + int res;
> + *pnode=p;
> + res = of_scan_flat_dt_ranges(pnode, p, target,
> + address,ignore);
> + if(res<0) {
> + /* Something bad happened */
> + return -1;
> + } else if(res>0) {
> + /* Something gooed happened. Translate. */
> + rc++;
> + pr_debug("translate %08lX %s\n", p, pathp);
> + if(flat_dt_translate_address(p, parent,
> + address)<0) {
> + return -1;
> + }
> + }
> + p=*pnode;
> + } else {
> + depth++;
> + }
> + } while (1);
> + *pnode=p;
> + return rc;
> +}
You don't need to implement this. drivers/of/fdt.c has functions that
already parse the flattened tree.
> +int __init early_init_dt_translate_address(unsigned long node, u64 *address)
> +{
> + unsigned long p = ((unsigned long)initial_boot_params) +
> + be32_to_cpu(initial_boot_params->off_dt_struct);
of_get_flat_dt_root()
> + return of_scan_flat_dt_ranges(&p, 0, node, address,0);
> +}
> +
>
> /**
> * unflatten_device_tree - create tree of device_nodes from flat blob
> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
> index 7bbf5b3..92e8694 100644
> --- a/include/linux/of_fdt.h
> +++ b/include/linux/of_fdt.h
> @@ -82,6 +82,8 @@ extern void early_init_dt_add_memory_arch(u64 base, u64
> size);
> extern u64 early_init_dt_alloc_memory_arch(u64 size, u64 align);
> extern u64 dt_mem_next_cell(int s, __be32 **cellp);
>
> +extern int early_init_dt_translate_address(unsigned long node, u64 *address);
> +
> /*
> * If BLK_DEV_INITRD, the fdt early init code will call this function,
> * to be provided by the arch code. start and end are specified as
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