| Message ID | 1473883618-14998-2-git-send-email-arbab@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On Wed, Sep 14, 2016 at 3:06 PM, Reza Arbab <arbab@linux.vnet.ibm.com> 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@linux.vnet.ibm.com> > --- > 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
On Thu, Sep 15, 2016 at 08:43:08AM -0500, Rob Herring wrote: >On Wed, Sep 14, 2016 at 3:06 PM, Reza Arbab <arbab@linux.vnet.ibm.com> wrote: >> + 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. Will do. >> @@ -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. I was trying to preserve that pr_debug output for these nodes, but I'm also fine with skipping it. Thanks for your feedback! I'll spin a v3 of this patchset soon.
On 15/09/16 06:06, Reza Arbab 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@linux.vnet.ibm.com> Makes sense, so basically a /memory@ with missing status or status = "okay" are added, others are skipped. No memblocks corresponding to those nodes are created either. Balbir Singh
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"); + 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; + early_init_dt_add_memory_arch(base, size); }
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@linux.vnet.ibm.com> --- drivers/of/fdt.c | 8 ++++++++ 1 file changed, 8 insertions(+)