[U-Boot] [PATCH] fdt: Fixup only valid memory banks

[U-Boot] [PATCH] fdt: Fixup only valid memory banks

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

Memory banks with address 0 and size 0 are empty and should not be
passed to the OS via device tree.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 common/fdt_support.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/common/fdt_support.c b/common/fdt_support.c
index 724452d75452..8b33f6773d27 100644
--- a/common/fdt_support.c
+++ b/common/fdt_support.c
@@ -457,7 +457,7 @@ int fdt_record_loadable(void *blob, u32 index, const char *name,
 int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[], int banks)
 {
 	int err, nodeoffset;
-	int len;
+	int len, i;
 	u8 tmp[MEMORY_BANKS_MAX * 16]; /* Up to 64-bit address + 64-bit size */
 
 	if (banks > MEMORY_BANKS_MAX) {
@@ -489,6 +489,12 @@ int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[], int banks)
 	if (!banks)
 		return 0;
 
+	for (i = 0; i < banks; i++)
+		if (start[i] == 0 && size[i] == 0)
+			break;
+
+	banks = i;
+
 	len = fdt_pack_reg(blob, tmp, start, size, banks);
 
 	err = fdt_setprop(blob, nodeoffset, "reg", tmp, len);
-- 
2.15.1

[U-Boot] [PATCH] fdt: Fixup only valid memory banks

[Lothar Waßmann]

Hi,

On Tue, 30 Jan 2018 11:34:17 +0100 Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
> 
> Memory banks with address 0 and size 0 are empty and should not be
> passed to the OS via device tree.
> 
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
>  common/fdt_support.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/common/fdt_support.c b/common/fdt_support.c
> index 724452d75452..8b33f6773d27 100644
> --- a/common/fdt_support.c
> +++ b/common/fdt_support.c
> @@ -457,7 +457,7 @@ int fdt_record_loadable(void *blob, u32 index, const char *name,
>  int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[], int banks)
>  {
>  	int err, nodeoffset;
> -	int len;
> +	int len, i;
>  	u8 tmp[MEMORY_BANKS_MAX * 16]; /* Up to 64-bit address + 64-bit size */
>  
>  	if (banks > MEMORY_BANKS_MAX) {
> @@ -489,6 +489,12 @@ int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[], int banks)
>  	if (!banks)
>  		return 0;
>  
> +	for (i = 0; i < banks; i++)
> +		if (start[i] == 0 && size[i] == 0)
> +			break;
> +
> +	banks = i;
> +
>  	len = fdt_pack_reg(blob, tmp, start, size, banks);
>  
>  	err = fdt_setprop(blob, nodeoffset, "reg", tmp, len);
>
Does an empty bank always imply the end of the list, or
Is it a valid scenario to have intervening empty banks?


Lothar Waßmann

[U-Boot] [PATCH] fdt: Fixup only valid memory banks

[Thierry Reding]

On Tue, Jan 30, 2018 at 12:41:15PM +0100, Lothar Waßmann wrote:
> Hi,
> 
> On Tue, 30 Jan 2018 11:34:17 +0100 Thierry Reding wrote:
> > From: Thierry Reding <treding@nvidia.com>
> > 
> > Memory banks with address 0 and size 0 are empty and should not be
> > passed to the OS via device tree.
> > 
> > Signed-off-by: Thierry Reding <treding@nvidia.com>
> > ---
> >  common/fdt_support.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> > 
> > diff --git a/common/fdt_support.c b/common/fdt_support.c
> > index 724452d75452..8b33f6773d27 100644
> > --- a/common/fdt_support.c
> > +++ b/common/fdt_support.c
> > @@ -457,7 +457,7 @@ int fdt_record_loadable(void *blob, u32 index, const char *name,
> >  int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[], int banks)
> >  {
> >  	int err, nodeoffset;
> > -	int len;
> > +	int len, i;
> >  	u8 tmp[MEMORY_BANKS_MAX * 16]; /* Up to 64-bit address + 64-bit size */
> >  
> >  	if (banks > MEMORY_BANKS_MAX) {
> > @@ -489,6 +489,12 @@ int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[], int banks)
> >  	if (!banks)
> >  		return 0;
> >  
> > +	for (i = 0; i < banks; i++)
> > +		if (start[i] == 0 && size[i] == 0)
> > +			break;
> > +
> > +	banks = i;
> > +
> >  	len = fdt_pack_reg(blob, tmp, start, size, banks);
> >  
> >  	err = fdt_setprop(blob, nodeoffset, "reg", tmp, len);
> >
> Does an empty bank always imply the end of the list, or
> Is it a valid scenario to have intervening empty banks?

I think it's a fair assumption that there aren't going to be any holes.
The vast majority of boards will only every initialize a single bank or
perhaps two. There's a few odd ones (hisilicon/hikey for example) that
adds more, but they are still all contiguous.

Thierry
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[U-Boot] [PATCH] fdt: Fixup only valid memory banks

[Stephen Warren]

On 01/30/2018 03:34 AM, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
> 
> Memory banks with address 0 and size 0 are empty and should not be
> passed to the OS via device tree.

>   	if (!banks)
>   		return 0;
>   
> +	for (i = 0; i < banks; i++)
> +		if (start[i] == 0 && size[i] == 0)
> +			break;
> +
> +	banks = i;

Do we want to move the for loop above the check for if (!banks)?

Should we put braces around the multi-line body of the for loop?

Aside from that,
Acked-by: Stephen Warren <swarren@nvidia.com>

> +
>   	len = fdt_pack_reg(blob, tmp, start, size, banks);
>   
>   	err = fdt_setprop(blob, nodeoffset, "reg", tmp, len);