Re: [PATCH V1 09/29] xen/dts: Add new helpers to use the device tree

[Julien Grall <julien.grall@linaro.org>]

On 09/06/2013 05:31 PM, Ian Campbell wrote:
> On Wed, 2013-08-28 at 15:47 +0100, Julien Grall wrote:
>> List of new helpers taken from linux (commit 74b9272):
>>      - dt_property_read_string
>>      - dt_match_node
>>      - dt_find_maching_node
>>      - dt_device_is_available
>>      - dt_prop_cmp
>>
>> Other new helpers:
>>      - dt_set_cell
>>      - for_each_child
>
> This seems too generic. Perhaps dt_for_each_child or for_each_dt_child?

Right, I will rename the function to dt_for_each_child.

>>      - dt_set_range
>>      - dt_cells_to_size
>>      - dt_next_cell
>>      - dt_get_range
>>      - dt_node_name_is_equal
>>      - dt_node_path_is_equal
>>      - dt_property_name_is_equal
>>
>> Signed-off-by: Julien Grall <julien.grall@linaro.org>
>>
>> ---
>>      Changes in v2:
>>          - Update commit message
>>          - Add for_each_child
>>          - Add dt_get_range
>>          - Update documentation
>>          - Typoes
>> ---
>>   xen/common/device_tree.c      |  109 +++++++++++++++++++++++++++--
>>   xen/include/xen/device_tree.h |  151 ++++++++++++++++++++++++++++++++++++++++-
>>   2 files changed, 252 insertions(+), 8 deletions(-)
>>
>> diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
>> index 07a19ac..833d67d 100644
>> --- a/xen/common/device_tree.c
>> +++ b/xen/common/device_tree.c
>> @@ -182,23 +182,38 @@ void __init device_tree_get_reg(const u32 **cell, u32 address_cells,
>>       get_val(cell, size_cells, size);
>>   }
>>
>> -static void __init set_val(u32 **cell, u32 cells, u64 val)
>> +void dt_get_range(const __be32 **cell, const struct dt_device_node *np,
>> +                  u64 *address, u64 *size)
>>   {
>> -    u32 c = cells;
>> +    *address = dt_next_cell(dt_n_addr_cells(np), cell);
>> +    *size = dt_next_cell(dt_n_size_cells(np), cell);
>> +}
>> +
>> +void dt_set_cell(__be32 **cellp, int size, u64 val)
>> +{
>> +    int cells = size;
>>
>> -    while ( c-- )
>> +    while ( size-- )
>>       {
>> -        (*cell)[c] = cpu_to_fdt32(val);
>> +        (*cellp)[size] = cpu_to_fdt32(val);
>>           val >>= 32;
>>       }
>> -    (*cell) += cells;
>> +
>> +    (*cellp) += cells;
>>   }
>>
>>   void __init device_tree_set_reg(u32 **cell, u32 address_cells, u32 size_cells,
>>                                   u64 start, u64 size)
>>   {
>> -    set_val(cell, address_cells, start);
>> -    set_val(cell, size_cells, size);
>> +    dt_set_cell(cell, address_cells, start);
>> +    dt_set_cell(cell, size_cells, size);
>> +}
>> +
>> +void dt_set_range(__be32 **cellp, const struct dt_device_node *np,
>> +                  u64 address, u64 size)
>> +{
>> +    dt_set_cell(cellp, dt_n_addr_cells(np), address);
>> +    dt_set_cell(cellp, dt_n_size_cells(np), size);
>>   }
>>
>>   u32 __init device_tree_get_u32(const void *fdt, int node, const char *prop_name,
>> @@ -583,6 +598,23 @@ bool_t dt_property_read_u32(const struct dt_device_node *np,
>>       return 1;
>>   }
>>
>> +int dt_property_read_string(const struct dt_device_node *np,
>> +                            const char *propname, const char **out_string)
>> +{
>> +    const struct dt_property *pp = dt_find_property(np, propname, NULL);
>> +
>> +    if ( !pp )
>> +        return -EINVAL;
>> +    if ( !pp->value )
>> +        return -ENODATA;
>> +    if ( strnlen(pp->value, pp->length) >= pp->length )
>> +        return -EILSEQ;
>> +
>> +    *out_string = pp->value;
>> +
>> +    return 0;
>> +}
>> +
>>   bool_t dt_device_is_compatible(const struct dt_device_node *device,
>>                                  const char *compat)
>>   {
>> @@ -655,6 +687,34 @@ struct dt_device_node *dt_find_node_by_alias(const char *alias)
>>       return NULL;
>>   }
>>
>> +bool_t dt_match_node(const struct dt_device_match *matches,
>> +                     const struct dt_device_node *node)
>> +{
>> +    if ( !matches )
>> +        return 0;
>> +
>> +    while ( matches->path || matches->type || matches->compatible )
>> +    {
>> +        bool_t match = 1;
>> +
>> +        if ( matches->path )
>> +            match &= dt_node_path_is_equal(node, matches->path);
>> +
>> +        if ( matches->type )
>> +            match &= dt_device_type_is_equal(node, matches->type);
>> +
>> +        if ( matches->compatible )
>> +            match &= dt_device_is_compatible(node, matches->compatible);
>> +
>> +        if ( match )
>> +            return match;
>> +
>> +        matches++;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>>   const struct dt_device_node *dt_get_parent(const struct dt_device_node *node)
>>   {
>>       if ( !node )
>> @@ -684,6 +744,23 @@ dt_find_compatible_node(struct dt_device_node *from,
>>       return np;
>>   }
>>
>> +struct dt_device_node *
>> +dt_find_matching_node(struct dt_device_node *from,
>> +                      const struct dt_device_match *matches)
>> +{
>> +    struct dt_device_node *np;
>> +    struct dt_device_node *dt;
>> +
>> +    dt = from ? from->allnext : dt_host;
>> +    for_each_device_node(dt, np)
>> +    {
>> +        if ( dt_match_node(matches, np) )
>> +            return np;
>> +    }
>> +
>> +    return NULL;
>> +}
>> +
>>   int dt_n_addr_cells(const struct dt_device_node *np)
>>   {
>>       const __be32 *ip;
>> @@ -1372,6 +1449,24 @@ int dt_device_get_irq(const struct dt_device_node *device, int index,
>>       return dt_irq_translate(&raw, out_irq);
>>   }
>>
>> +bool_t dt_device_is_available(const struct dt_device_node *device)
>> +{
>> +    const char *status;
>> +    u32 statlen;
>> +
>> +    status = dt_get_property(device, "status", &statlen);
>> +    if ( status == NULL )
>> +        return 1;
>> +
>> +    if ( statlen > 0 )
>> +    {
>> +        if ( !strcmp(status, "okay") || !strcmp(status, "ok") )
>> +            return 1;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>>   /**
>>    * unflatten_dt_node - Alloc and populate a device_node from the flat tree
>>    * @fdt: The parent device tree blob
>> diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
>> index 7cbf736..fa4f314 100644
>> --- a/xen/include/xen/device_tree.h
>> +++ b/xen/include/xen/device_tree.h
>> @@ -54,6 +54,19 @@ struct dt_early_info {
>>       struct dt_module_info modules;
>>   };
>>
>> +/*
>> + * Struct used for matching a device
>> + */
>> +struct dt_device_match {
>> +    const char *path;
>> +    const char *type;
>> +    const char *compatible;
>> +};
>> +
>> +#define DT_MATCH_PATH(p)                { .path = p }
>> +#define DT_MATCH_TYPE(typ)              { .type = typ }
>> +#define DT_MATCH_COMPATIBLE(compat)     { .compatible = compat }
>> +
>>   typedef u32 dt_phandle;
>>
>>   /**
>> @@ -229,6 +242,7 @@ extern const struct dt_device_node *dt_interrupt_controller;
>>    */
>>   struct dt_device_node * __init dt_find_interrupt_controller(const char *compat);
>>
>> +#define dt_prop_cmp(s1, s2) strcmp((s1), (s2))
>>   #define dt_node_cmp(s1, s2) strcasecmp((s1), (s2))
>>   #define dt_compat_cmp(s1, s2) strcasecmp((s1), (s2))
>>
>> @@ -242,6 +256,9 @@ struct dt_device_node * __init dt_find_interrupt_controller(const char *compat);
>>   #define for_each_device_node(dt, dn)                         \
>>       for ( dn = dt; dn != NULL; dn = dn->allnext )
>>
>> +#define for_each_child_node(dt, dn)                         \
>> +    for ( dn = dt->child; dn != NULL; dn = dn->sibling )
>> +
>>   /* Helper to read a big number; size is in cells (not bytes) */
>>   static inline u64 dt_read_number(const __be32 *cell, int size)
>>   {
>> @@ -252,6 +269,20 @@ static inline u64 dt_read_number(const __be32 *cell, int size)
>>       return r;
>>   }
>>
>> +/* Helper to convert a number of cells in bytes */
>> +static inline int dt_cells_to_size(int size)
>> +{
>> +    return (size * sizeof (u32));
>> +}
>> +
>> +static inline u64 dt_next_cell(int s, const __be32 **cellp)
>> +{
>> +    const __be32 *p = *cellp;
>> +
>> +    *cellp = p + s;
>> +    return dt_read_number(p, s);
>> +}
>> +
>>   static inline const char *dt_node_full_name(const struct dt_device_node *np)
>>   {
>>       return (np && np->full_name) ? np->full_name : "<no-node>";
>> @@ -262,6 +293,18 @@ static inline const char *dt_node_name(const struct dt_device_node *np)
>>       return (np && np->name) ? np->name : "<no-node>";
>>   }
>>
>> +static inline bool_t dt_node_name_is_equal(const struct dt_device_node *np,
>> +                                           const char *name)
>> +{
>> +    return !dt_node_cmp(np->name, name);
>> +}
>> +
>> +static inline bool_t dt_node_path_is_equal(const struct dt_device_node *np,
>> +                                           const char *path)
>> +{
>> +    return !dt_node_cmp(np->full_name, path);
>> +}
>> +
>>   static inline bool_t
>>   dt_device_type_is_equal(const struct dt_device_node *device,
>>                           const char *type)
>> @@ -281,6 +324,12 @@ static inline domid_t dt_device_used_by(const struct dt_device_node *device)
>>       return device->used_by;
>>   }
>>
>> +static inline bool_t dt_property_name_is_equal(const struct dt_property *pp,
>> +                                               const char *name)
>> +{
>> +    return !dt_prop_cmp(pp->name, name);
>> +}
>> +
>>   /**
>>    * dt_find_compatible_node - Find a node based on type and one of the
>>    *                           tokens in its "compatible" property
>> @@ -315,6 +364,23 @@ const void *dt_get_property(const struct dt_device_node *np,
>>    */
>>   bool_t dt_property_read_u32(const struct dt_device_node *np,
>>                               const char *name, u32 *out_value);
>> +/**
>> + * dt_property_read_string - Find and read a string from a property
>> + * @np:         Device node from which the property value is to be read
>> + * @propname:   Name of the property to be searched
>> + * @out_string: Pointer to null terminated return string, modified only
>> + *              if return value if 0.
>> + *
>> + * Search for a property in a device tree node and retrieve a null
>> + * terminated string value (pointer to data, not a copy). Returns 0 on
>> + * success, -EINVAL if the property does not exist, -ENODATA if property
>> + * doest not have value, and -EILSEQ if the string is not
>> + * null-terminated with the length of the property data.
>> + *
>> + * The out_string pointer is modified only if a valid string can be decoded.
>> + */
>> +int dt_property_read_string(const struct dt_device_node *np,
>> +                            const char *propname, const char **out_string);
>>
>>   /**
>>    * Checks if the given "compat" string matches one of the strings in
>> @@ -450,4 +516,87 @@ int dt_n_size_cells(const struct dt_device_node *np);
>>    */
>>   int dt_n_addr_cells(const struct dt_device_node *np);
>>
>> -#endif
>> +/**
>> + * dt_device_is_available - Check if a device is available for use
>> + *
>> + * @device: Node to check for availability
>> + *
>> + * Returns true if the status property is absent or set to "okay" or "ok",
>> + * false otherwise.
>> + */
>> +bool_t dt_device_is_available(const struct dt_device_node *device);
>> +
>> +/**
>> + * dt_match_node - Tell if a device_node has a matching of dt_device_match
>> + * @matches: array of dt_device_match structures to search in
>> + * @node: the dt_device_node structure to match against
>> + *
>> + * Returns true if the device node match one of dt_device_match.
>> + */
>> +bool_t dt_match_node(const struct dt_device_match *matches,
>> +                     const struct dt_device_node *node);
>> +
>> +/**
>> + * dt_find_matching_node - Find a node based on an dt_device_match match table
>> + * @from: The node to start searching from or NULL, the node you pass
>> + *        will not be searched, only the next one will; typically, you pass
>> + *        what the returned call returned
>> + * @matches: array of dt_device_match structures to search in
>> + *
>> + * Returns a node pointer.
>> + */
>> +struct dt_device_node *
>> +dt_find_matching_node(struct dt_device_node *from,
>> +                      const struct dt_device_match *matches);
>> +
>> +/**
>> + * dt_set_cell - Write a value into a series of cells
>> + *
>> + * @cellp: Pointer to cells
>> + * @size: number of cells to write the value
>> + * @value: number to write
>> + *
>> + * Write a value into a series of cells and update cellp to point to the
>> + * cell just after.
>> + */
>> +void dt_set_cell(__be32 **cellp, int size, u64 val);
>> +
>> +/**
>> + * dt_set_range - Write range into a series of cells
>> + *
>> + * @cellp: Pointer to cells
>> + * @np: Node which contains the encoding for the address and the size
>> + * @address: Start of range
>> + * @size: Size of the range
>> + *
>> + * Write a range into a series of cells and update cellp to point to the
>> + * cell just after.
>> + */
>> +void dt_set_range(__be32 **cellp, const struct dt_device_node *np,
>> +                  u64 address, u64 size);
>> +
>> +/**
>> + * dt_get_range - Read a range (address/size) from a series of cells
>> + *
>> + * @cellp: Pointer to cells
>> + * @np Node which  contains the encoding for the addresss and the size
>> + * @address: Address filled by this function
>> + * @size: Size filled by this function
>> + *
>> + * WARNING: This function should not be used to decode an address
>> + * This function reads a range (address/size) from a series of cells and
>> + * update cellp to point to the cell just after.
>> + */
>> +void dt_get_range(const __be32 **cellp, const struct dt_device_node *np,
>> +                  u64 *address, u64 *size);
>> +
>> +#endif /* __XEN_DEVICE_TREE_H */
>> +
>> +/*
>> + * Local variables:
>> + * mode: C
>> + * c-file-style: "BSD"
>> + * c-basic-offset: 4
>> + * indent-tabs-mode: nil
>> + * End:
>> + */
>
>


-- 
Julien Grall