diff options
| -rw-r--r-- | drivers/dma/of-dma.c | 76 | ||||
| -rw-r--r-- | include/linux/of_dma.h | 6 |
2 files changed, 22 insertions, 60 deletions
diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c index 2882403a39c..7aa0864cd48 100644 --- a/drivers/dma/of-dma.c +++ b/drivers/dma/of-dma.c @@ -13,38 +13,31 @@ #include <linux/device.h> #include <linux/err.h> #include <linux/module.h> -#include <linux/rculist.h> +#include <linux/mutex.h> #include <linux/slab.h> #include <linux/of.h> #include <linux/of_dma.h> static LIST_HEAD(of_dma_list); -static DEFINE_SPINLOCK(of_dma_lock); +static DEFINE_MUTEX(of_dma_lock); /** - * of_dma_get_controller - Get a DMA controller in DT DMA helpers list + * of_dma_find_controller - Get a DMA controller in DT DMA helpers list * @dma_spec: pointer to DMA specifier as found in the device tree * * Finds a DMA controller with matching device node and number for dma cells - * in a list of registered DMA controllers. If a match is found the use_count - * variable is increased and a valid pointer to the DMA data stored is retuned. - * A NULL pointer is returned if no match is found. + * in a list of registered DMA controllers. If a match is found a valid pointer + * to the DMA data stored is retuned. A NULL pointer is returned if no match is + * found. */ -static struct of_dma *of_dma_get_controller(struct of_phandle_args *dma_spec) +static struct of_dma *of_dma_find_controller(struct of_phandle_args *dma_spec) { struct of_dma *ofdma; - spin_lock(&of_dma_lock); - list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers) if ((ofdma->of_node == dma_spec->np) && - (ofdma->of_dma_nbcells == dma_spec->args_count)) { - ofdma->use_count++; - spin_unlock(&of_dma_lock); + (ofdma->of_dma_nbcells == dma_spec->args_count)) return ofdma; - } - - spin_unlock(&of_dma_lock); pr_debug("%s: can't find DMA controller %s\n", __func__, dma_spec->np->full_name); @@ -53,22 +46,6 @@ static struct of_dma *of_dma_get_controller(struct of_phandle_args *dma_spec) } /** - * of_dma_put_controller - Decrement use count for a registered DMA controller - * @of_dma: pointer to DMA controller data - * - * Decrements the use_count variable in the DMA data structure. This function - * should be called only when a valid pointer is returned from - * of_dma_get_controller() and no further accesses to data referenced by that - * pointer are needed. - */ -static void of_dma_put_controller(struct of_dma *ofdma) -{ - spin_lock(&of_dma_lock); - ofdma->use_count--; - spin_unlock(&of_dma_lock); -} - -/** * of_dma_controller_register - Register a DMA controller to DT DMA helpers * @np: device node of DMA controller * @of_dma_xlate: translation function which converts a phandle @@ -114,12 +91,11 @@ int of_dma_controller_register(struct device_node *np, ofdma->of_dma_nbcells = nbcells; ofdma->of_dma_xlate = of_dma_xlate; ofdma->of_dma_data = data; - ofdma->use_count = 0; /* Now queue of_dma controller structure in list */ - spin_lock(&of_dma_lock); + mutex_lock(&of_dma_lock); list_add_tail(&ofdma->of_dma_controllers, &of_dma_list); - spin_unlock(&of_dma_lock); + mutex_unlock(&of_dma_lock); return 0; } @@ -131,32 +107,20 @@ EXPORT_SYMBOL_GPL(of_dma_controller_register); * * Memory allocated by of_dma_controller_register() is freed here. */ -int of_dma_controller_free(struct device_node *np) +void of_dma_controller_free(struct device_node *np) { struct of_dma *ofdma; - spin_lock(&of_dma_lock); - - if (list_empty(&of_dma_list)) { - spin_unlock(&of_dma_lock); - return -ENODEV; - } + mutex_lock(&of_dma_lock); list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers) if (ofdma->of_node == np) { - if (ofdma->use_count) { - spin_unlock(&of_dma_lock); - return -EBUSY; - } - list_del(&ofdma->of_dma_controllers); - spin_unlock(&of_dma_lock); kfree(ofdma); - return 0; + break; } - spin_unlock(&of_dma_lock); - return -ENODEV; + mutex_unlock(&of_dma_lock); } EXPORT_SYMBOL_GPL(of_dma_controller_free); @@ -219,15 +183,15 @@ struct dma_chan *of_dma_request_slave_channel(struct device_node *np, if (of_dma_match_channel(np, name, i, &dma_spec)) continue; - ofdma = of_dma_get_controller(&dma_spec); + mutex_lock(&of_dma_lock); + ofdma = of_dma_find_controller(&dma_spec); - if (ofdma) { + if (ofdma) chan = ofdma->of_dma_xlate(&dma_spec, ofdma); - - of_dma_put_controller(ofdma); - } else { + else chan = NULL; - } + + mutex_unlock(&of_dma_lock); of_node_put(dma_spec.np); diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h index ce6a8ab3d2b..364dda73487 100644 --- a/include/linux/of_dma.h +++ b/include/linux/of_dma.h @@ -25,7 +25,6 @@ struct of_dma { struct dma_chan *(*of_dma_xlate) (struct of_phandle_args *, struct of_dma *); void *of_dma_data; - int use_count; }; struct of_dma_filter_info { @@ -38,7 +37,7 @@ extern int of_dma_controller_register(struct device_node *np, struct dma_chan *(*of_dma_xlate) (struct of_phandle_args *, struct of_dma *), void *data); -extern int of_dma_controller_free(struct device_node *np); +extern void of_dma_controller_free(struct device_node *np); extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np, const char *name); extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec, @@ -52,9 +51,8 @@ static inline int of_dma_controller_register(struct device_node *np, return -ENODEV; } -static inline int of_dma_controller_free(struct device_node *np) +static inline void of_dma_controller_free(struct device_node *np) { - return -ENODEV; } static inline struct dma_chan *of_dma_request_slave_channel(struct device_node *np, |