Re: [U-Boot] [PATCH] fdt: Fix fdtdec_get_addr_size() for 64-bit
On Sun, Aug 02, 2015 at 03:27:53PM -0600, Simon Glass wrote:
Hi,
On 27 July 2015 at 11:13, Simon Glass s...@chromium.org wrote:
Hi,
On 23 July 2015 at 10:51, Stephen Warren swar...@wwwdotorg.org wrote:
From: Thierry Reding tred...@nvidia.com
Signed-off-by: Thierry Reding tred...@nvidia.com
Signed-off-by: Tom Warren twar...@nvidia.com
Signed-off-by: Stephen Warren swar...@nvidia.com
---
Simon,
When Thierry first posted this patch, you responded:
+ parent = fdt_parent_offset(blob, node);
This function is very slow as it must scan the whole tree. Can we
instead pass in the parent node?
I don't think that's possible in general. This function is called from
fdtdec_get_addr(), and it's easy to find call sites of that function that
don't have the parent node available. IIRC, the first couple of example I
found scan the DT for a node with a certain compatible value, or look up
nodes via aliases, rather than being called while parsing the DT in a
top-down tree-like fashion, where the parent node is easily available. I
didn't do an exhaustive search after I found a few problematic cases.
Also, how about (in addition) a
version of this function that works for devices? Like:
device_get_addr_size(struct udevice *dev, ...)
so that it can handle this for you.
That sounds like a separate patch?
Yes, but I think we should get it in there so that people don't start
using this (wildly inefficient) function when they don't need to. I
think by passing in the parent node we force people to think about the
cost.
Yes the driver model function can be a separate patch, but let's get
it in at about the same time. We have dev_get_addr() so could have
dev_get_addr_size().
Equally, I see that struct udevice contains an of_offset field, but no
parent_of_offset or similar. There is a struct udevice *parent though;
is the struct udevice hierarchy guaranteed to 100% match the DT
hierarchy? I know this isn't necessarily guaranteed in Linux's device
model for example.
Yes it is 100% guaranteed, so dev-parent-of_offset will do the right
thing.
As such, this patch seems OK to me as-is.
---
lib/fdtdec.c | 56
1 file changed, 36 insertions(+), 20 deletions(-)
This patch has been applied. I'm going to post a revert of this patch.
Please can you take a look at the comments above? In particular this
function is called from dev_get_addr() which is a core driver model
function. It needs to be fast - and in fact dev_get_addr() already has
access to the parent node.
Perhaps this could be fixed by doing passing in the parent as an
optional argument and then do something like this:
if (parent 0) {
parent = fdt_parent_offset(blob, node);
if (parent 0) {
...
}
}
In that case callers that have access to the parent node already can
pass it in, but others can simply pass in -1 and have the function do
the lookup.
Also looking a bit closer this patch does a lot more than 'fix it for
64-bit'. A commit message would be useful to explain what problems it
is fixing, etc.
Another point is that fdt_addr_t and fdt_size_t are supposed to match
the address size used in the device tree. Is that not the case with
Tegra210?
You can't assume that #address-cells and #size-cells will be 2 for all
64-bit platforms. Some may well go with #address-cells = 1 and #size-
cells = 1, and I've seen others do #address-cells = 2 and #size-cells =
1. All of these combinations are perfectly valid.
As such, fdt_addr_t and fdt_size_t make sense only if they are the
maximum that the architecture can support. Even so an address could
technically be larger than that, if it's behind a translated bus, for
example.
So what this does is really fix parsing of address and size cells in the
general case, though it would still fail for values of #address-cells or
#size-cells bigger than 2 (because we don't have a datatype that would
be able to contain such large values).
Note that there's also still a corner case that this doesn't handle. The
DT specification states, if I remember correctly, that #address-cells
and #size-cells are inherited. That means with the current code we will
wrongly parse something like this:
/ {
...
#address-cells = 1;
#size-cells = 1;
...
bus@ {
...
device@ {
...
reg = 0x 0x1000;
...
};
...
};
...
};
According to the DT specification the bus@ node would inherit
#address-cells = 1 and #size-cells = 1 from the root node. However
Re: [U-Boot] [PATCH] fdt: Fix fdtdec_get_addr_size() for 64-bit
On 08/04/2015 08:26 AM, Thierry Reding wrote:
... [ discussion of new fdtdec_get_addr_size() implementation]
So what this does is really fix parsing of address and size cells in the
general case, though it would still fail for values of #address-cells or
#size-cells bigger than 2 (because we don't have a datatype that would
be able to contain such large values).
Note that there's also still a corner case that this doesn't handle. The
DT specification states, if I remember correctly, that #address-cells
and #size-cells are inherited. That means with the current code we will
wrongly parse something like this:
/ {
...
#address-cells = 1;
#size-cells = 1;
...
bus@ {
...
device@ {
...
reg = 0x 0x1000;
...
};
...
};
...
};
According to the DT specification the bus@ node would inherit
#address-cells = 1 and #size-cells = 1 from the root node. However
with libfdt what really happens is that since bus@ does not have
either property it will default to 2 in both cases. I'm not sure if this
really is a problem. Typically nodes are not nested that deeply, or if
they are then, typically, they explicitly contain #address-cells and
#size-cells properties.
I don't think #address-cells/#size-cells do actually get inherited.
Admittedly some other properties (e.g. interrupt-parent) do, but
according to:
https://lists.ozlabs.org/pipermail/linuxppc-dev/2008-January/049113.html
[PATCH] powerpc: #address-cells #size-cells properties not inherited
... and my vague memory, these two don't.
You can search Google for e.g. #address-cells inherited and find a
number of similar assertions.
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Re: [U-Boot] [PATCH] fdt: Fix fdtdec_get_addr_size() for 64-bit
On Tue, Aug 04, 2015 at 09:23:27AM -0600, Stephen Warren wrote:
On 08/04/2015 08:26 AM, Thierry Reding wrote:
... [ discussion of new fdtdec_get_addr_size() implementation]
So what this does is really fix parsing of address and size cells in the
general case, though it would still fail for values of #address-cells or
#size-cells bigger than 2 (because we don't have a datatype that would
be able to contain such large values).
Note that there's also still a corner case that this doesn't handle. The
DT specification states, if I remember correctly, that #address-cells
and #size-cells are inherited. That means with the current code we will
wrongly parse something like this:
/ {
...
#address-cells = 1;
#size-cells = 1;
...
bus@ {
...
device@ {
...
reg = 0x 0x1000;
...
};
...
};
...
};
According to the DT specification the bus@ node would inherit
#address-cells = 1 and #size-cells = 1 from the root node. However
with libfdt what really happens is that since bus@ does not have
either property it will default to 2 in both cases. I'm not sure if this
really is a problem. Typically nodes are not nested that deeply, or if
they are then, typically, they explicitly contain #address-cells and
#size-cells properties.
I don't think #address-cells/#size-cells do actually get inherited.
Admittedly some other properties (e.g. interrupt-parent) do, but according
to:
https://lists.ozlabs.org/pipermail/linuxppc-dev/2008-January/049113.html
[PATCH] powerpc: #address-cells #size-cells properties not inherited
... and my vague memory, these two don't.
You can search Google for e.g. #address-cells inherited and find a number
of similar assertions.
Okay, that's good. It means there's not even a corner case. =)
Thierry
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Re: [U-Boot] [PATCH] fdt: Fix fdtdec_get_addr_size() for 64-bit
Hi,
On 27 July 2015 at 11:13, Simon Glass s...@chromium.org wrote:
Hi,
On 23 July 2015 at 10:51, Stephen Warren swar...@wwwdotorg.org wrote:
From: Thierry Reding tred...@nvidia.com
Signed-off-by: Thierry Reding tred...@nvidia.com
Signed-off-by: Tom Warren twar...@nvidia.com
Signed-off-by: Stephen Warren swar...@nvidia.com
---
Simon,
When Thierry first posted this patch, you responded:
+ parent = fdt_parent_offset(blob, node);
This function is very slow as it must scan the whole tree. Can we
instead pass in the parent node?
I don't think that's possible in general. This function is called from
fdtdec_get_addr(), and it's easy to find call sites of that function that
don't have the parent node available. IIRC, the first couple of example I
found scan the DT for a node with a certain compatible value, or look up
nodes via aliases, rather than being called while parsing the DT in a
top-down tree-like fashion, where the parent node is easily available. I
didn't do an exhaustive search after I found a few problematic cases.
Also, how about (in addition) a
version of this function that works for devices? Like:
device_get_addr_size(struct udevice *dev, ...)
so that it can handle this for you.
That sounds like a separate patch?
Yes, but I think we should get it in there so that people don't start
using this (wildly inefficient) function when they don't need to. I
think by passing in the parent node we force people to think about the
cost.
Yes the driver model function can be a separate patch, but let's get
it in at about the same time. We have dev_get_addr() so could have
dev_get_addr_size().
Equally, I see that struct udevice contains an of_offset field, but no
parent_of_offset or similar. There is a struct udevice *parent though;
is the struct udevice hierarchy guaranteed to 100% match the DT
hierarchy? I know this isn't necessarily guaranteed in Linux's device
model for example.
Yes it is 100% guaranteed, so dev-parent-of_offset will do the right thing.
As such, this patch seems OK to me as-is.
---
lib/fdtdec.c | 56
1 file changed, 36 insertions(+), 20 deletions(-)
This patch has been applied. I'm going to post a revert of this patch.
Please can you take a look at the comments above? In particular this
function is called from dev_get_addr() which is a core driver model
function. It needs to be fast - and in fact dev_get_addr() already has
access to the parent node.
Also looking a bit closer this patch does a lot more than 'fix it for
64-bit'. A commit message would be useful to explain what problems it
is fixing, etc.
Another point is that fdt_addr_t and fdt_size_t are supposed to match
the address size used in the device tree. Is that not the case with
Tegra210?
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 9c6b3619da24..56e72eafaade 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -88,29 +88,45 @@ const char *fdtdec_get_compatible(enum fdt_compat_id id)
fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,
const char *prop_name, fdt_size_t *sizep)
{
- const fdt_addr_t *cell;
- int len;
+ const fdt32_t *ptr, *end;
+ int parent, na, ns, len;
+ fdt_addr_t addr;
debug(%s: %s: , __func__, prop_name);
- cell = fdt_getprop(blob, node, prop_name, len);
- if (cell ((!sizep len == sizeof(fdt_addr_t)) ||
-len == sizeof(fdt_addr_t) * 2)) {
- fdt_addr_t addr = fdt_addr_to_cpu(*cell);
- if (sizep) {
- const fdt_size_t *size;
-
- size = (fdt_size_t *)((char *)cell +
- sizeof(fdt_addr_t));
- *sizep = fdt_size_to_cpu(*size);
- debug(addr=%08lx, size=%llx\n,
- (ulong)addr, (u64)*sizep);
- } else {
- debug(%08lx\n, (ulong)addr);
- }
- return addr;
+
+ parent = fdt_parent_offset(blob, node);
+ if (parent 0) {
+ debug((no parent found)\n);
+ return FDT_ADDR_T_NONE;
}
- debug((not found)\n);
- return FDT_ADDR_T_NONE;
+
+ na = fdt_address_cells(blob, parent);
+ ns = fdt_size_cells(blob, parent);
+
+ ptr = fdt_getprop(blob, node, prop_name, len);
+ if (!ptr) {
+ debug((not found)\n);
+ return FDT_ADDR_T_NONE;
+ }
+
+ end = ptr + len / sizeof(*ptr);
+
+ if (ptr + na + ns end) {
+ debug((not enough data: expected %d bytes, got %d bytes)\n,
+ (na + ns) * 4, len);
+ return FDT_ADDR_T_NONE;
+ }
+
+ addr = fdtdec_get_number(ptr, na);
+
+ if (sizep) {
+ *sizep = fdtdec_get_number(ptr + na, ns);
+
Re: [U-Boot] [PATCH] fdt: Fix fdtdec_get_addr_size() for 64-bit
Hi,
On 23 July 2015 at 10:51, Stephen Warren swar...@wwwdotorg.org wrote:
From: Thierry Reding tred...@nvidia.com
Signed-off-by: Thierry Reding tred...@nvidia.com
Signed-off-by: Tom Warren twar...@nvidia.com
Signed-off-by: Stephen Warren swar...@nvidia.com
---
Simon,
When Thierry first posted this patch, you responded:
+ parent = fdt_parent_offset(blob, node);
This function is very slow as it must scan the whole tree. Can we
instead pass in the parent node?
I don't think that's possible in general. This function is called from
fdtdec_get_addr(), and it's easy to find call sites of that function that
don't have the parent node available. IIRC, the first couple of example I
found scan the DT for a node with a certain compatible value, or look up
nodes via aliases, rather than being called while parsing the DT in a
top-down tree-like fashion, where the parent node is easily available. I
didn't do an exhaustive search after I found a few problematic cases.
Also, how about (in addition) a
version of this function that works for devices? Like:
device_get_addr_size(struct udevice *dev, ...)
so that it can handle this for you.
That sounds like a separate patch?
Yes, but I think we should get it in there so that people don't start
using this (wildly inefficient) function when they don't need to. I
think by passing in the parent node we force people to think about the
cost.
Yes the driver model function can be a separate patch, but let's get
it in at about the same time. We have dev_get_addr() so could have
dev_get_addr_size().
Equally, I see that struct udevice contains an of_offset field, but no
parent_of_offset or similar. There is a struct udevice *parent though;
is the struct udevice hierarchy guaranteed to 100% match the DT
hierarchy? I know this isn't necessarily guaranteed in Linux's device
model for example.
Yes it is 100% guaranteed, so dev-parent-of_offset will do the right thing.
As such, this patch seems OK to me as-is.
---
lib/fdtdec.c | 56
1 file changed, 36 insertions(+), 20 deletions(-)
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 9c6b3619da24..56e72eafaade 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -88,29 +88,45 @@ const char *fdtdec_get_compatible(enum fdt_compat_id id)
fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,
const char *prop_name, fdt_size_t *sizep)
{
- const fdt_addr_t *cell;
- int len;
+ const fdt32_t *ptr, *end;
+ int parent, na, ns, len;
+ fdt_addr_t addr;
debug(%s: %s: , __func__, prop_name);
- cell = fdt_getprop(blob, node, prop_name, len);
- if (cell ((!sizep len == sizeof(fdt_addr_t)) ||
-len == sizeof(fdt_addr_t) * 2)) {
- fdt_addr_t addr = fdt_addr_to_cpu(*cell);
- if (sizep) {
- const fdt_size_t *size;
-
- size = (fdt_size_t *)((char *)cell +
- sizeof(fdt_addr_t));
- *sizep = fdt_size_to_cpu(*size);
- debug(addr=%08lx, size=%llx\n,
- (ulong)addr, (u64)*sizep);
- } else {
- debug(%08lx\n, (ulong)addr);
- }
- return addr;
+
+ parent = fdt_parent_offset(blob, node);
+ if (parent 0) {
+ debug((no parent found)\n);
+ return FDT_ADDR_T_NONE;
}
- debug((not found)\n);
- return FDT_ADDR_T_NONE;
+
+ na = fdt_address_cells(blob, parent);
+ ns = fdt_size_cells(blob, parent);
+
+ ptr = fdt_getprop(blob, node, prop_name, len);
+ if (!ptr) {
+ debug((not found)\n);
+ return FDT_ADDR_T_NONE;
+ }
+
+ end = ptr + len / sizeof(*ptr);
+
+ if (ptr + na + ns end) {
+ debug((not enough data: expected %d bytes, got %d bytes)\n,
+ (na + ns) * 4, len);
+ return FDT_ADDR_T_NONE;
+ }
+
+ addr = fdtdec_get_number(ptr, na);
+
+ if (sizep) {
+ *sizep = fdtdec_get_number(ptr + na, ns);
+ debug(addr=%pa, size=%pa\n, addr, sizep);
+ } else {
+ debug(%pa\n, addr);
+ }
+
+ return addr;
}
fdt_addr_t fdtdec_get_addr(const void *blob, int node,
--
1.9.1
Regards,
SImon
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[U-Boot] [PATCH] fdt: Fix fdtdec_get_addr_size() for 64-bit
From: Thierry Reding tred...@nvidia.com
Signed-off-by: Thierry Reding tred...@nvidia.com
Signed-off-by: Tom Warren twar...@nvidia.com
Signed-off-by: Stephen Warren swar...@nvidia.com
---
Simon,
When Thierry first posted this patch, you responded:
+ parent = fdt_parent_offset(blob, node);
This function is very slow as it must scan the whole tree. Can we
instead pass in the parent node?
I don't think that's possible in general. This function is called from
fdtdec_get_addr(), and it's easy to find call sites of that function that
don't have the parent node available. IIRC, the first couple of example I
found scan the DT for a node with a certain compatible value, or look up
nodes via aliases, rather than being called while parsing the DT in a
top-down tree-like fashion, where the parent node is easily available. I
didn't do an exhaustive search after I found a few problematic cases.
Also, how about (in addition) a
version of this function that works for devices? Like:
device_get_addr_size(struct udevice *dev, ...)
so that it can handle this for you.
That sounds like a separate patch?
Equally, I see that struct udevice contains an of_offset field, but no
parent_of_offset or similar. There is a struct udevice *parent though;
is the struct udevice hierarchy guaranteed to 100% match the DT
hierarchy? I know this isn't necessarily guaranteed in Linux's device
model for example.
As such, this patch seems OK to me as-is.
---
lib/fdtdec.c | 56
1 file changed, 36 insertions(+), 20 deletions(-)
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 9c6b3619da24..56e72eafaade 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -88,29 +88,45 @@ const char *fdtdec_get_compatible(enum fdt_compat_id id)
fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,
const char *prop_name, fdt_size_t *sizep)
{
- const fdt_addr_t *cell;
- int len;
+ const fdt32_t *ptr, *end;
+ int parent, na, ns, len;
+ fdt_addr_t addr;
debug(%s: %s: , __func__, prop_name);
- cell = fdt_getprop(blob, node, prop_name, len);
- if (cell ((!sizep len == sizeof(fdt_addr_t)) ||
-len == sizeof(fdt_addr_t) * 2)) {
- fdt_addr_t addr = fdt_addr_to_cpu(*cell);
- if (sizep) {
- const fdt_size_t *size;
-
- size = (fdt_size_t *)((char *)cell +
- sizeof(fdt_addr_t));
- *sizep = fdt_size_to_cpu(*size);
- debug(addr=%08lx, size=%llx\n,
- (ulong)addr, (u64)*sizep);
- } else {
- debug(%08lx\n, (ulong)addr);
- }
- return addr;
+
+ parent = fdt_parent_offset(blob, node);
+ if (parent 0) {
+ debug((no parent found)\n);
+ return FDT_ADDR_T_NONE;
}
- debug((not found)\n);
- return FDT_ADDR_T_NONE;
+
+ na = fdt_address_cells(blob, parent);
+ ns = fdt_size_cells(blob, parent);
+
+ ptr = fdt_getprop(blob, node, prop_name, len);
+ if (!ptr) {
+ debug((not found)\n);
+ return FDT_ADDR_T_NONE;
+ }
+
+ end = ptr + len / sizeof(*ptr);
+
+ if (ptr + na + ns end) {
+ debug((not enough data: expected %d bytes, got %d bytes)\n,
+ (na + ns) * 4, len);
+ return FDT_ADDR_T_NONE;
+ }
+
+ addr = fdtdec_get_number(ptr, na);
+
+ if (sizep) {
+ *sizep = fdtdec_get_number(ptr + na, ns);
+ debug(addr=%pa, size=%pa\n, addr, sizep);
+ } else {
+ debug(%pa\n, addr);
+ }
+
+ return addr;
}
fdt_addr_t fdtdec_get_addr(const void *blob, int node,
--
1.9.1
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