On Wed, Mar 16, 2016 at 11:42 AM, Joerg Roedel <j...@8bytes.org> wrote: > From: Joerg Roedel <jroe...@suse.de> > > Getting the arguments of phandles is somewhat limited at the > moement, because the number of arguments supported by core > code is limited to MAX_PHANDLE_ARGS, which is set to 16 > currently. > > In case of the arm smmu this is not enough, as the 128 > supported stream-ids are encoded in device-tree with > arguments to phandles. On some systems with more than 16 > stream-ids this causes a WARN_ON being triggered at boot and > an incomplete initialization of the smmu. > > This patch-set implements an iterator interface over > phandles which allows to parse out arbitrary numbers of > arguments per phandle. The existing function for parsing > them, __of_parse_phandle_with_args(), is converted to make > use of the iterator.
This mostly looks fine to me, but it is kind of a lot of functions just for this one thing. For example, I think the caller can track the index themselves if they care about it. I'd also like to see a more standard style for_each type iterator define rather than open coded while loops. Some minor style comments below. > Signed-off-by: Joerg Roedel <jroe...@suse.de> > --- > drivers/of/base.c | 219 > ++++++++++++++++++++++++++++++----------------------- > include/linux/of.h | 95 +++++++++++++++++++++++ > 2 files changed, 220 insertions(+), 94 deletions(-) > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index 017dd94..9a5f199 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -1439,119 +1439,150 @@ void of_print_phandle_args(const char *msg, const > struct of_phandle_args *args) > printk("\n"); > } > > -static int __of_parse_phandle_with_args(const struct device_node *np, > - const char *list_name, > - const char *cells_name, > - int cell_count, int index, > - struct of_phandle_args *out_args) > +int of_phandle_iterator_init(struct of_phandle_iterator *it, > + const struct device_node *np, > + const char *list_name, > + const char *cells_name, > + int cell_count) > { > - const __be32 *list, *list_end; > - int rc = 0, size, cur_index = 0; > - uint32_t count = 0; > - struct device_node *node = NULL; > - phandle phandle; > + const __be32 *list; > + int size; > > /* Retrieve the phandle list property */ > list = of_get_property(np, list_name, &size); > if (!list) > return -ENOENT; > - list_end = list + size / sizeof(*list); > > - /* Loop over the phandles until all the requested entry is found */ > - while (list < list_end) { > - rc = -EINVAL; > - count = 0; > + it->np = np; > + it->node = NULL; > + it->list = list; > + it->phandle_end = list; > + it->list_end = list + size / sizeof(*list); > + it->cells_name = cells_name; > + it->cell_count = cell_count; > + it->cur_index = -1; > > - /* > - * If phandle is 0, then it is an empty entry with no > - * arguments. Skip forward to the next entry. > - */ > - phandle = be32_to_cpup(list++); > - if (phandle) { > - /* > - * Find the provider node and parse the #*-cells > - * property to determine the argument length. > - * > - * This is not needed if the cell count is hard-coded > - * (i.e. cells_name not set, but cell_count is set), > - * except when we're going to return the found node > - * below. > - */ > - if (cells_name || cur_index == index) { > - node = of_find_node_by_phandle(phandle); > - if (!node) { > - pr_err("%s: could not find phandle\n", > - np->full_name); > - goto err; > - } > - } > + return 0; > +} > > - if (cells_name) { > - if (of_property_read_u32(node, cells_name, > - &count)) { > - pr_err("%s: could not get %s for > %s\n", > - np->full_name, cells_name, > - node->full_name); > - goto err; > - } > - } else { > - count = cell_count; > - } > +int of_phandle_iterator_next(struct of_phandle_iterator *it) > +{ > + phandle phandle = 0; > + uint32_t count = 0; > > - /* > - * Make sure that the arguments actually fit in the > - * remaining property data length > - */ > - if (list + count > list_end) { > - pr_err("%s: arguments longer than property\n", > - np->full_name); > - goto err; > - } > + if (it->phandle_end >= it->list_end) > + return -ENOENT; > + > + if (it->node) { > + of_node_put(it->node); > + it->node = NULL; > + } > + > + it->list = it->phandle_end; > + it->cur_index += 1; it->cur_index++; > + phandle = be32_to_cpup(it->list++); Please, just <space>=<space>. > + > + if (phandle) { > + if (it->cells_name) { > + it->node = of_find_node_by_phandle(phandle); > + if (!it->node) > + goto no_node; All these goto's are pretty pointless and can just be printk and return. > + > + if (of_property_read_u32(it->node, > + it->cells_name, > + &count)) > + goto no_property; > + } else { > + count = it->cell_count; > } > > - /* > - * All of the error cases above bail out of the loop, so at > - * this point, the parsing is successful. If the requested > - * index matches, then fill the out_args structure and return, > - * or return -ENOENT for an empty entry. > - */ > + if (it->list + count > it->list_end) > + goto too_many_args; > + } > + > + it->phandle_end = it->list + count; > + it->cur_count = count; > + it->phandle = phandle; single space. > + > + return 0; > + > +no_node: > + pr_err("%s: could not find phandle\n", it->np->full_name); > + > + return -EINVAL; > + > +no_property: > + pr_err("%s: could not get %s for %s\n", it->np->full_name, > + it->cells_name, it->node->full_name); > + > + return -EINVAL; > + > +too_many_args: > + pr_err("%s: arguments longer than property\n", it->np->full_name); > + > + return -EINVAL; > +} > + > +int of_phandle_iterator_args(struct of_phandle_iterator *it, > + uint32_t *args, > + int size) > +{ > + int i, count; > + > + count = it->cur_count; > + > + if (WARN_ON(size < count)) > + count = size; > + > + for (i = 0; i < count; i++) > + args[i] = be32_to_cpup(it->list++); > + > + return count; > +} > + > +static int __of_parse_phandle_with_args(const struct device_node *np, > + const char *list_name, > + const char *cells_name, > + int cell_count, int index, > + struct of_phandle_args *out_args) > +{ > + struct of_phandle_iterator it; > + int rc; > + > + rc = of_phandle_iterator_init(&it, np, list_name, > + cells_name, cell_count); > + if (rc) > + return rc; > + > + while ((rc = of_phandle_iterator_next(&it)) == 0) { > + uint32_t count; > + int cur_index; > + > + count = of_phandle_iterator_count(&it); > + cur_index = of_phandle_iterator_index(&it); > + > rc = -ENOENT; > if (cur_index == index) { > - if (!phandle) > - goto err; > - > - if (out_args) { > - int i; > - if (WARN_ON(count > MAX_PHANDLE_ARGS)) > - count = MAX_PHANDLE_ARGS; > - out_args->np = node; > - out_args->args_count = count; > - for (i = 0; i < count; i++) > - out_args->args[i] = > be32_to_cpup(list++); > - } else { > - of_node_put(node); > - } > + if (!of_phandle_iterator_phandle(&it)) > + break; > + > + rc = 0; > > /* Found it! return success */ > - return 0; > - } > + if (!out_args) > + break; > > - of_node_put(node); > - node = NULL; > - list += count; > - cur_index++; > + out_args->np = of_phandle_iterator_node(&it); > + out_args->args_count = of_phandle_iterator_args(&it, > + > out_args->args, > + > MAX_PHANDLE_ARGS); > + > + break; > + } > } > > - /* > - * Unlock node before returning result; will be one of: > - * -ENOENT : index is for empty phandle > - * -EINVAL : parsing error on data > - * [1..n] : Number of phandle (count mode; when index = -1) > - */ > - rc = index < 0 ? cur_index : -ENOENT; > - err: > - if (node) > - of_node_put(node); > + of_phandle_iterator_destroy(&it); > + > return rc; > } > > diff --git a/include/linux/of.h b/include/linux/of.h > index dc6e396..31e6ee9 100644 > --- a/include/linux/of.h > +++ b/include/linux/of.h > @@ -75,6 +75,19 @@ struct of_phandle_args { > uint32_t args[MAX_PHANDLE_ARGS]; > }; > > +struct of_phandle_iterator { > + const struct device_node *np; > + const __be32 *list; > + const __be32 *list_end; > + const __be32 *phandle_end; > + phandle phandle; > + struct device_node *node; np and node? If you need both, name them based on what they point to. > + const char *cells_name; > + int cell_count; > + int cur_index; > + uint32_t cur_count; > +}; > + > struct of_reconfig_data { > struct device_node *dn; > struct property *prop; > @@ -334,6 +347,50 @@ extern int of_parse_phandle_with_fixed_args(const struct > device_node *np, > extern int of_count_phandle_with_args(const struct device_node *np, > const char *list_name, const char *cells_name); > > +/* phandle iterator functions */ > +extern int of_phandle_iterator_init(struct of_phandle_iterator *it, > + const struct device_node *np, > + const char *list_name, > + const char *cells_name, > + int cell_count); > + > +static inline void of_phandle_iterator_destroy(struct of_phandle_iterator > *it) > +{ > + if (it->node) > + of_node_put(it->node); > +} > + > +extern int of_phandle_iterator_next(struct of_phandle_iterator *it); > + > +static inline int of_phandle_iterator_index(const struct of_phandle_iterator > *it) > +{ > + return it->cur_index; > +} > + > +static inline uint32_t of_phandle_iterator_count(const struct > of_phandle_iterator *it) > +{ > + return it->cur_count; > +} > + > +static inline uint32_t of_phandle_iterator_phandle(const struct > of_phandle_iterator *it) > +{ > + return it->phandle; > +} > + > +static inline struct device_node *of_phandle_iterator_node(struct > of_phandle_iterator *it) > +{ > + if (!it->node) > + it->node = of_find_node_by_phandle(it->phandle); > + > + if (it->node) > + of_node_get(it->node); The above function may have already done the get. Not sure offhand. > + > + return it->node; > +} > + > +extern int of_phandle_iterator_args(struct of_phandle_iterator *it, > + uint32_t *args, > + int size); > extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align)); > extern int of_alias_get_id(struct device_node *np, const char *stem); > extern int of_alias_get_highest_id(const char *stem); > @@ -608,6 +665,44 @@ static inline int of_count_phandle_with_args(struct > device_node *np, > return -ENOSYS; > } > > +static inline int of_phandle_iterator_init(struct of_phandle_iterator *it, > + const struct device_node *np, > + const char *list_name, > + const char *cells_name, > + int cell_count) > +{ > + return -ENOSYS; > +} > + > +static inline void of_phandle_iterator_destroy(struct of_phandle_iterator > *it) > +{ > +} > + > +static inline int of_phandle_iterator_next(struct of_phandle_iterator *it) > +{ > + return -ENOSYS; > +} > + > +static inline int of_phandle_iterator_index(const struct of_phandle_iterator > *it) > +{ > + return -1; > +} > + > +static inline uint32_t of_phandle_iterator_count(const struct > of_phandle_iterator *it) > +{ > + return 0; > +} > + > +static inline uint32_t of_phandle_iterator_phandle(const struct > of_phandle_iterator *it) > +{ > + return 0; > +} > + > +static inline struct device_node *of_phandle_iterator_node(struct > of_phandle_iterator *it) > +{ > + return NULL; > +} > + > static inline int of_alias_get_id(struct device_node *np, const char *stem) > { > return -ENOSYS; > -- > 1.9.1 > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu