On Wed, Sep 14, 2016 at 3:06 PM, Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx> wrote:
> Respect the standard dt "status" property when scanning memory nodes in
> early_init_dt_scan_memory(), so that if the property is present and not
> "okay", no memory will be added.
>
> The use case at hand is accelerator or device memory, which may be
> unusable until post-boot initialization of the memory link. Such a node
> can be described in the dt as any other, given its status is "disabled".
> Per the device tree specification,
>
> "disabled"
> Indicates that the device is not presently operational, but it
> might become operational in the future (for example, something
> is not plugged in, or switched off).
>
> Once such memory is made operational, it can then be hotplugged.
>
> Signed-off-by: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/of/fdt.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 085c638..fc19590 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -1022,8 +1022,10 @@ int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
> int depth, void *data)
> {
> const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
> + const char *status;
> const __be32 *reg, *endp;
> int l;
> + bool add_memory;
>
> /* We are scanning "memory" nodes only */
> if (type == NULL) {
> @@ -1044,6 +1046,9 @@ int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
>
> endp = reg + (l / sizeof(__be32));
>
> + status = of_get_flat_dt_prop(node, "status", NULL);
> + add_memory = !status || !strcmp(status, "okay");
Move this into it's own function to mirror the unflattened version
(of_device_is_available). Also, make sure the logic is the same. IIRC,
"ok" is also allowed.
> +
> pr_debug("memory scan node %s, reg size %d,\n", uname, l);
>
> while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
> @@ -1057,6 +1062,9 @@ int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
> pr_debug(" - %llx , %llx\n", (unsigned long long)base,
> (unsigned long long)size);
>
> + if (!add_memory)
> + continue;
There's no point in checking this in the loop. status applies to the
whole node. Just return up above.
Rob
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