2 files changed, 155 insertions, 0 deletions
diff --git a/drivers/staging/media/ipu3/ipu3-css-pool.c b/drivers/staging/media/ipu3/ipu3-css-pool.c
new file mode 100644
index 000000000000..6f271f81669b
--- /dev/null
+++ b/drivers/staging/media/ipu3/ipu3-css-pool.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Intel Corporation
+
+#include <linux/device.h>
+
+#include "ipu3.h"
+#include "ipu3-css-pool.h"
+#include "ipu3-dmamap.h"
+
+int ipu3_css_dma_buffer_resize(struct imgu_device *imgu,
+			       struct ipu3_css_map *map, size_t size)
+{
+	if (map->size < size && map->vaddr) {
+		dev_warn(&imgu->pci_dev->dev, "dma buf resized from %zu to %zu",
+			 map->size, size);
+
+		ipu3_dmamap_free(imgu, map);
+		if (!ipu3_dmamap_alloc(imgu, map, size))
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
+void ipu3_css_pool_cleanup(struct imgu_device *imgu, struct ipu3_css_pool *pool)
+{
+	unsigned int i;
+
+	for (i = 0; i < IPU3_CSS_POOL_SIZE; i++)
+		ipu3_dmamap_free(imgu, &pool->entry[i].param);
+}
+
+int ipu3_css_pool_init(struct imgu_device *imgu, struct ipu3_css_pool *pool,
+		       size_t size)
+{
+	unsigned int i;
+
+	for (i = 0; i < IPU3_CSS_POOL_SIZE; i++) {
+		pool->entry[i].valid = false;
+		if (size == 0) {
+			pool->entry[i].param.vaddr = NULL;
+			continue;
+		}
+
+		if (!ipu3_dmamap_alloc(imgu, &pool->entry[i].param, size))
+			goto fail;
+	}
+
+	pool->last = IPU3_CSS_POOL_SIZE;
+
+	return 0;
+
+fail:
+	ipu3_css_pool_cleanup(imgu, pool);
+	return -ENOMEM;
+}
+
+/*
+ * Allocate a new parameter via recycling the oldest entry in the pool.
+ */
+void ipu3_css_pool_get(struct ipu3_css_pool *pool)
+{
+	/* Get the oldest entry */
+	u32 n = (pool->last + 1) % IPU3_CSS_POOL_SIZE;
+
+	pool->entry[n].valid = true;
+	pool->last = n;
+}
+
+/*
+ * Undo, for all practical purposes, the effect of pool_get().
+ */
+void ipu3_css_pool_put(struct ipu3_css_pool *pool)
+{
+	pool->entry[pool->last].valid = false;
+	pool->last = (pool->last + IPU3_CSS_POOL_SIZE - 1) % IPU3_CSS_POOL_SIZE;
+}
+
+/**
+ * ipu3_css_pool_last - Retrieve the nth pool entry from last
+ *
+ * @pool: a pointer to &struct ipu3_css_pool.
+ * @n: the distance to the last index.
+ *
+ * Returns:
+ *  The nth entry from last or null map to indicate no frame stored.
+ */
+const struct ipu3_css_map *
+ipu3_css_pool_last(struct ipu3_css_pool *pool, unsigned int n)
+{
+	static const struct ipu3_css_map null_map = { 0 };
+	int i = (pool->last + IPU3_CSS_POOL_SIZE - n) % IPU3_CSS_POOL_SIZE;
+
+	WARN_ON(n >= IPU3_CSS_POOL_SIZE);
+
+	if (!pool->entry[i].valid)
+		return &null_map;
+
+	return &pool->entry[i].param;
+}
diff --git a/drivers/staging/media/ipu3/ipu3-css-pool.h b/drivers/staging/media/ipu3/ipu3-css-pool.h
new file mode 100644
index 000000000000..2657c39a4d71
--- /dev/null
+++ b/drivers/staging/media/ipu3/ipu3-css-pool.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2018 Intel Corporation */
+
+#ifndef __IPU3_UTIL_H
+#define __IPU3_UTIL_H
+
+struct device;
+struct imgu_device;
+
+#define IPU3_CSS_POOL_SIZE		4
+
+/**
+ * ipu3_css_map - store DMA mapping info for buffer
+ *
+ * @size:		size of the buffer in bytes.
+ * @vaddr:		kernel virtual address.
+ * @daddr:		iova dma address to access IPU3.
+ * @vma:		private, a pointer to &struct vm_struct,
+ *			used for ipu3_dmamap_free.
+ */
+struct ipu3_css_map {
+	size_t size;
+	void *vaddr;
+	dma_addr_t daddr;
+	struct vm_struct *vma;
+};
+
+/**
+ * ipu3_css_pool - circular buffer pool definition
+ *
+ * @entry:		array with IPU3_CSS_POOL_SIZE elements.
+ * @entry.param:	a &struct ipu3_css_map for storing the mem mapping.
+ * @entry.valid:	used to mark if the entry has valid data.
+ * @last:		write pointer, initialized to IPU3_CSS_POOL_SIZE.
+ */
+struct ipu3_css_pool {
+	struct {
+		struct ipu3_css_map param;
+		bool valid;
+	} entry[IPU3_CSS_POOL_SIZE];
+	u32 last;
+};
+
+int ipu3_css_dma_buffer_resize(struct imgu_device *imgu,
+			       struct ipu3_css_map *map, size_t size);
+void ipu3_css_pool_cleanup(struct imgu_device *imgu,
+			   struct ipu3_css_pool *pool);
+int ipu3_css_pool_init(struct imgu_device *imgu, struct ipu3_css_pool *pool,
+		       size_t size);
+void ipu3_css_pool_get(struct ipu3_css_pool *pool);
+void ipu3_css_pool_put(struct ipu3_css_pool *pool);
+const struct ipu3_css_map *ipu3_css_pool_last(struct ipu3_css_pool *pool,
+					      u32 last);
+
+#endif