tee: optee: add optee-specific shared pool implementation

This is simple pool that uses kernel page allocator. This pool can be
used in case OP-TEE supports dynamic shared memory.
Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

drivers/tee/optee/Makefile

@@ -4,3 +4,4 @@ optee-objs += core.o
 optee-objs += call.o
 optee-objs += rpc.o
 optee-objs += supp.o
+optee-objs += shm_pool.o

drivers/tee/optee/shm_pool.c

+/*
+ * Copyright (c) 2015, Linaro Limited
+ * Copyright (c) 2017, EPAM Systems
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/device.h>
+#include <linux/dma-buf.h>
+#include <linux/genalloc.h>
+#include <linux/slab.h>
+#include <linux/tee_drv.h>
+#include "optee_private.h"
+#include "optee_smc.h"
+#include "shm_pool.h"
+
+static int pool_op_alloc(struct tee_shm_pool_mgr *poolm,
+			 struct tee_shm *shm, size_t size)
+{
+	unsigned int order = get_order(size);
+	struct page *page;
+
+	page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
+	if (!page)
+		return -ENOMEM;
+
+	shm->kaddr = page_address(page);
+	shm->paddr = page_to_phys(page);
+	shm->size = PAGE_SIZE << order;
+
+	return 0;
+}
+
+static void pool_op_free(struct tee_shm_pool_mgr *poolm,
+			 struct tee_shm *shm)
+{
+	free_pages((unsigned long)shm->kaddr, get_order(shm->size));
+	shm->kaddr = NULL;
+}
+
+static void pool_op_destroy_poolmgr(struct tee_shm_pool_mgr *poolm)
+{
+	kfree(poolm);
+}
+
+static const struct tee_shm_pool_mgr_ops pool_ops = {
+	.alloc = pool_op_alloc,
+	.free = pool_op_free,
+	.destroy_poolmgr = pool_op_destroy_poolmgr,
+};
+
+/**
+ * optee_shm_pool_alloc_pages() - create page-based allocator pool
+ *
+ * This pool is used when OP-TEE supports dymanic SHM. In this case
+ * command buffers and such are allocated from kernel's own memory.
+ */
+struct tee_shm_pool_mgr *optee_shm_pool_alloc_pages(void)
+{
+	struct tee_shm_pool_mgr *mgr = kzalloc(sizeof(*mgr), GFP_KERNEL);
+
+	if (!mgr)
+		return ERR_PTR(-ENOMEM);
+
+	mgr->ops = &pool_ops;
+
+	return mgr;
+}

drivers/tee/optee/shm_pool.h

+/*
+ * Copyright (c) 2015, Linaro Limited
+ * Copyright (c) 2016, EPAM Systems
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef SHM_POOL_H
+#define SHM_POOL_H
+
+#include <linux/tee_drv.h>
+
+struct tee_shm_pool_mgr *optee_shm_pool_alloc_pages(void);
+
+#endif