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path: root/drivers/misc/mei/dma-ring.c
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Diffstat (limited to 'drivers/misc/mei/dma-ring.c')
-rw-r--r--drivers/misc/mei/dma-ring.c99
1 files changed, 99 insertions, 0 deletions
diff --git a/drivers/misc/mei/dma-ring.c b/drivers/misc/mei/dma-ring.c
new file mode 100644
index 000000000000..56f4c0882a20
--- /dev/null
+++ b/drivers/misc/mei/dma-ring.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright(c) 2016 - 2018 Intel Corporation. All rights reserved.
+ */
+#include <linux/dma-mapping.h>
+#include <linux/mei.h>
+
+#include "mei_dev.h"
+
+/**
+ * mei_dmam_dscr_alloc() - allocate a managed coherent buffer
+ * for the dma descriptor
+ * @dev: mei_device
+ * @dscr: dma descriptor
+ *
+ * Return:
+ * * 0 - on success or zero allocation request
+ * * -EINVAL - if size is not power of 2
+ * * -ENOMEM - of allocation has failed
+ */
+static int mei_dmam_dscr_alloc(struct mei_device *dev,
+ struct mei_dma_dscr *dscr)
+{
+ if (!dscr->size)
+ return 0;
+
+ if (WARN_ON(!is_power_of_2(dscr->size)))
+ return -EINVAL;
+
+ if (dscr->vaddr)
+ return 0;
+
+ dscr->vaddr = dmam_alloc_coherent(dev->dev, dscr->size, &dscr->daddr,
+ GFP_KERNEL);
+ if (!dscr->vaddr)
+ return -ENOMEM;
+
+ return 0;
+}
+
+/**
+ * mei_dmam_dscr_free() - free a managed coherent buffer
+ * from the dma descriptor
+ * @dev: mei_device
+ * @dscr: dma descriptor
+ */
+static void mei_dmam_dscr_free(struct mei_device *dev,
+ struct mei_dma_dscr *dscr)
+{
+ if (!dscr->vaddr)
+ return;
+
+ dmam_free_coherent(dev->dev, dscr->size, dscr->vaddr, dscr->daddr);
+ dscr->vaddr = NULL;
+}
+
+/**
+ * mei_dmam_ring_free() - free dma ring buffers
+ * @dev: mei device
+ */
+void mei_dmam_ring_free(struct mei_device *dev)
+{
+ int i;
+
+ for (i = 0; i < DMA_DSCR_NUM; i++)
+ mei_dmam_dscr_free(dev, &dev->dr_dscr[i]);
+}
+
+/**
+ * mei_dmam_ring_alloc() - allocate dma ring buffers
+ * @dev: mei device
+ *
+ * Return: -ENOMEM on allocation failure 0 otherwise
+ */
+int mei_dmam_ring_alloc(struct mei_device *dev)
+{
+ int i;
+
+ for (i = 0; i < DMA_DSCR_NUM; i++)
+ if (mei_dmam_dscr_alloc(dev, &dev->dr_dscr[i]))
+ goto err;
+
+ return 0;
+
+err:
+ mei_dmam_ring_free(dev);
+ return -ENOMEM;
+}
+
+/**
+ * mei_dma_ring_is_allocated() - check if dma ring is allocated
+ * @dev: mei device
+ *
+ * Return: true if dma ring is allocated
+ */
+bool mei_dma_ring_is_allocated(struct mei_device *dev)
+{
+ return !!dev->dr_dscr[DMA_DSCR_HOST].vaddr;
+}