dma: add functionality to grant access to DMA devices

Add helper functions to provide a list of all Zephyr DMA devices
and to grant a user thread access to them.

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Author: kv2019i

zephyr/include/rtos/userspace_helper.h

@@ -120,6 +120,13 @@ int user_access_to_mailbox(struct k_mem_domain *domain, k_tid_t thread_id);
  */
 void user_grant_dai_access_all(struct k_thread *thread);
 
+/**
+ * Grant DMA device access to a user-space thread.
+ *
+ * @param thread user-space thread for which DMA access is granted
+ */
+void user_grant_dma_access_all(struct k_thread *thread);
+
 #else
 
 static inline int user_access_to_mailbox(struct k_mem_domain *domain, k_tid_t thread_id)

zephyr/include/sof/lib/dma.h

@@ -343,6 +343,13 @@ static inline const struct dma_info *dma_info_get(void)
 	return sof_get()->dma_info;
 }
 
+/**
+ * \brief Retrieve the list of all DMA devices.
+ * \param count Pointer to store the number of devices in the list.
+ * \return Pointer to the array of device pointers.
+ */
+const struct device **dma_get_device_list(size_t *count);
+
 /** @}*/
 
 #endif /* __SOF_LIB_DMA_H__ */

zephyr/lib/dma.c

@@ -219,6 +219,20 @@ const struct dma_info lib_dma = {
 	.num_dmas = ARRAY_SIZE(dma)
 };
 
+const struct device **dma_get_device_list(size_t *count)
+{
+	static const struct device *device_list[ARRAY_SIZE(dma)];
+	int i;
+
+	if (count)
+		*count = ARRAY_SIZE(dma);
+
+	for (i = 0; i < ARRAY_SIZE(dma); i++)
+		device_list[i] = dma[i].z_dev;
+
+	return device_list;
+}
+
 /* Initialize all platform DMAC's */
 int dmac_init(struct sof *sof)
 {

zephyr/lib/userspace_helper.c

@@ -20,6 +20,7 @@
 #include <sof/audio/module_adapter/library/userspace_proxy.h>
 #include <sof/lib/mailbox.h>
 #include <sof/lib/dai.h>
+#include <sof/lib/dma.h>
 
 #define MODULE_DRIVER_HEAP_CACHED		CONFIG_SOF_ZEPHYR_HEAP_CACHED
 
@@ -146,6 +147,21 @@ void user_grant_dai_access_all(struct k_thread *thread)
 	LOG_DBG("Granted DAI access to thread %p for %zu devices", thread, count);
 }
 
+void user_grant_dma_access_all(struct k_thread *thread)
+{
+	const struct device **devices;
+	size_t count;
+	size_t i;
+
+	devices = dma_get_device_list(&count);
+
+	for (i = 0; i < count; i++) {
+		k_thread_access_grant(thread, devices[i]);
+		LOG_DBG("Granted DMA device access: %d %s to thread %p",
+			i, devices[i]->name, thread);
+	}
+}
+
 #else /* CONFIG_USERSPACE */
 
 void *user_stack_allocate(size_t stack_size, uint32_t options)