On Wed, Jun 22, 2011 at 10:22 AM, Thomas Abraham
<thomas.abraham@xxxxxxxxxx> wrote:
>
> I have added the functions as you have suggested and the diff is
> listed below. Could you please review the diff and suggest any changes
> required.
Thanks Thomas. Comments below...
> drivers/of/base.c | 129 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/of.h | 10 ++++
> 2 files changed, 139 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index 632ebae..73f0144 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -596,6 +596,135 @@ struct device_node
> *of_find_node_by_phandle(phandle handle)
> EXPORT_SYMBOL(of_find_node_by_phandle);
>
> /**
> + * of_read_property_u32 - Reads a indexed 32-bit property value
> + * @prop: property to read from.
> + * @offset: cell number to read.
> + * value: returned cell value
> + *
> + * Returns a indexed 32-bit value of a property cell, -EINVAL in case the cell
> + * does not exist
> + */
> +int of_read_property_u32(struct property *prop, u32 offset, u32 *value)
> +{
> + if (!prop || !prop->value)
> + return -EINVAL;
Hmmm, it would probably be a good idea to differentiate return code
depending on whether or not the property was found vs. the property
data not large enough.
> + if ((offset + 1) * 4 > prop->length)
> + return -EINVAL;
> +
> + *value = of_read_ulong(prop->value + (offset * 4), 1);
> + return 0;
Despite the fact that this is exactly what I asked you to write, this
ends up being rather ugly. (I originally put in the '*4' to match the
behaviour of the existing of_read_number(), but that was a mistake.
tglx also pointed it out). How about this instead:
int of_read_property_u32(struct property *prop, unsigned int offset,
u32 *out_value)
{
if (!prop || !out_value)
return -EINVAL;
if (!prop->value)
return -ENODATA;
if (offset + sizeof(*out_value) > prop->length)
return -EOVERFLOW;
*out_value = be32_to_cpup(prop->data + offset);
return 0;
}
int of_read_property_u64(struct property *prop, unsigned int offset,
u64 *out_value)
{
if (!prop || !out_value)
return -EINVAL;
if (!prop->value)
return -ENODATA;
if (offset + sizeof(*out_value) > prop->length)
return -EOVERFLOW;
*out_value = be32_to_cpup(prop->value + offset);
*out_value = (*out_value << 32) | be32_to_cpup(prop->value +
offset + sizeof(u32));
return 0;
}
> +}
> +EXPORT_SYMBOL(of_read_property_u32);
EXPORT_SYMBOL_GPL()
> +
> +/**
> + * of_getprop_u32 - Find a property in a device node and read a 32-bit value
> + * @np: device node from which the property value is to be read.
> + * @propname name of the property to be searched.
> + * @offset: cell number to read.
> + * @value: returned value of the cell
> + *
> + * Search for a property in a device node and read a indexed 32-bit value of a
> + * property cell. Returns the 32-bit cell value, -EINVAL in case the
> property or
> + * the indexed cell does not exist.
> + */
> +int
> +of_getprop_u32(struct device_node *np, char *propname, int offset, u32 *value)
> +{
> + return of_read_property_u32(of_find_property(np, propname, NULL),
> + offset, value);
> +}
> +EXPORT_SYMBOL(of_getprop_u32);
> +
> +/**
> + * of_read_property_u64 - Reads a indexed 64-bit property value
> + * @prop: property to read from.
> + * @offset: cell number to read (each cell is 64-bits).
> + * @value: returned cell value
> + *
> + * Returns a indexed 64-bit value of a property cell, -EINVAL in case the cell
> + * does not exist
> + */
> +int of_read_property_u64(struct property *prop, int offset, u64 *value)
> +{
> + if (!prop || !prop->value)
> + return -EINVAL;
> + if ((offset + 1) * 8 > prop->length)
> + return -EINVAL;
> +
> + *value = of_read_number(prop->value + (offset * 8), 2);
> + return 0;
> +}
> +EXPORT_SYMBOL(of_read_property_u64);
> +
> +/**
> + * of_getprop_u64 - Find a property in a device node and read a 64-bit value
> + * @np: device node from which the property value is to be read.
> + * @propname name of the property to be searched.
> + * @offset: cell number to read (each cell is 64-bits).
> + * @value: returned value of the cell
> + *
> + * Search for a property in a device node and read a indexed 64-bit value of a
> + * property cell. Returns the 64-bit cell value, -EINVAL in case the
> property or
> + * the indexed cell does not exist.
> + */
> +int
> +of_getprop_u64(struct device_node *np, char *propname, int offset, u64 *value)
> +{
> + return of_read_property_u64(of_find_property(np, propname, NULL),
> + offset, value);
> +}
> +EXPORT_SYMBOL(of_getprop_u64);
> +
> +/**
> + * of_read_property_string - Returns a pointer to a indexed null terminated
> + * property value string
> + * @prop: property to read from.
> + * @offset: index of the property string to be read.
> + * @string: pointer to a null terminated string, valid only if the return
> + * value is 0.
> + *
> + * Returns a pointer to a indexed null terminated property cell string, -EINVAL
> + * in case the cell does not exist.
> + */
> +int of_read_property_string(struct property *prop, int offset, char **string)
> +{
> + char *c;
> +
> + if (!prop || !prop->value)
> + return -EINVAL;
Ditto here about return values.
> +
> + c = (char *)prop->value;
You don't need the cast. prop->value is a void* pointer. However,
'c' does need to be const char.
> + while (offset--)
> + while (*c++)
> + ;
Rather than open coding this, you should use the string library
functions. Something like:
c = prop->value;
while (offset-- && (c - prop->value) < prop->size)
c += strlen(c) + 1;
if ((c - prop->value) + strlen(c) >= prop->size)
return -EOVERFLOW;
*out_value = c;
Plus it catches more error conditions that way.
g.
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