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-rw-r--r--drivers/dma/dmaengine.c2
-rw-r--r--drivers/dma/of-dma.c96
-rw-r--r--include/linux/dmaengine.h4
-rw-r--r--include/linux/of_dma.h10
4 files changed, 37 insertions, 75 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 1b2df59d1d65..93f7992bee5c 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -560,7 +560,7 @@ EXPORT_SYMBOL_GPL(__dma_request_channel);
* @dev: pointer to client device structure
* @name: slave channel name
*/
-struct dma_chan *dma_request_slave_channel(struct device *dev, char *name)
+struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name)
{
/* If device-tree is present get slave info from here */
if (dev->of_node)
diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index 69d04d28b1ef..7aa0864cd487 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -13,43 +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);
-
- if (list_empty(&of_dma_list)) {
- spin_unlock(&of_dma_lock);
- return NULL;
- }
-
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);
@@ -58,22 +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
@@ -93,6 +65,7 @@ int of_dma_controller_register(struct device_node *np,
{
struct of_dma *ofdma;
int nbcells;
+ const __be32 *prop;
if (!np || !of_dma_xlate) {
pr_err("%s: not enough information provided\n", __func__);
@@ -103,8 +76,11 @@ int of_dma_controller_register(struct device_node *np,
if (!ofdma)
return -ENOMEM;
- nbcells = be32_to_cpup(of_get_property(np, "#dma-cells", NULL));
- if (!nbcells) {
+ prop = of_get_property(np, "#dma-cells", NULL);
+ if (prop)
+ nbcells = be32_to_cpup(prop);
+
+ if (!prop || !nbcells) {
pr_err("%s: #dma-cells property is missing or invalid\n",
__func__);
kfree(ofdma);
@@ -115,12 +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;
}
@@ -132,32 +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);
@@ -172,8 +135,8 @@ EXPORT_SYMBOL_GPL(of_dma_controller_free);
* specifiers, matches the name provided. Returns 0 if the name matches and
* a valid pointer to the DMA specifier is found. Otherwise returns -ENODEV.
*/
-static int of_dma_match_channel(struct device_node *np, char *name, int index,
- struct of_phandle_args *dma_spec)
+static int of_dma_match_channel(struct device_node *np, const char *name,
+ int index, struct of_phandle_args *dma_spec)
{
const char *s;
@@ -198,7 +161,7 @@ static int of_dma_match_channel(struct device_node *np, char *name, int index,
* Returns pointer to appropriate dma channel on success or NULL on error.
*/
struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
- char *name)
+ const char *name)
{
struct of_phandle_args dma_spec;
struct of_dma *ofdma;
@@ -220,14 +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);
-
- if (!ofdma)
- continue;
+ mutex_lock(&of_dma_lock);
+ ofdma = of_dma_find_controller(&dma_spec);
- chan = ofdma->of_dma_xlate(&dma_spec, ofdma);
+ if (ofdma)
+ chan = ofdma->of_dma_xlate(&dma_spec, ofdma);
+ else
+ chan = NULL;
- of_dma_put_controller(ofdma);
+ mutex_unlock(&of_dma_lock);
of_node_put(dma_spec.np);
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index dd6d21b335c8..96d3e4ab11a9 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -969,7 +969,7 @@ enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx);
void dma_issue_pending_all(void);
struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
dma_filter_fn fn, void *fn_param);
-struct dma_chan *dma_request_slave_channel(struct device *dev, char *name);
+struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name);
void dma_release_channel(struct dma_chan *chan);
#else
static inline enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
@@ -985,7 +985,7 @@ static inline struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
return NULL;
}
static inline struct dma_chan *dma_request_slave_channel(struct device *dev,
- char *name)
+ const char *name)
{
return NULL;
}
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index d15073e080dd..364dda734877 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 {
@@ -38,9 +37,9 @@ 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,
- char *name);
+ const char *name);
extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
#else
@@ -52,13 +51,12 @@ 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,
- char *name)
+ const char *name)
{
return NULL;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-20 18:47:36 +0000