#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);
return NULL;
}
-/**
- * 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
{
struct of_dma *ofdma;
int nbcells;
+ const __be32 *prop;
if (!np || !of_dma_xlate) {
pr_err("%s: not enough information provided\n", __func__);
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);
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;
}
*
* 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);
* 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;
* 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;
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);
projects / firefly-linux-kernel-4.4.55.git / blobdiff