diff --git a/drivers/intel/soc/stratix10/io/s10_memmap_qspi.c b/drivers/intel/soc/stratix10/io/s10_memmap_qspi.c
index a0fc034..dcd1991 100644
--- a/drivers/intel/soc/stratix10/io/s10_memmap_qspi.c
+++ b/drivers/intel/soc/stratix10/io/s10_memmap_qspi.c
@@ -26,9 +26,9 @@
 	 * valid.
 	 */
 	int		in_use;
-	uintptr_t	base;
-	size_t		file_pos;
-	size_t		size;
+	uintptr_t		base;
+	unsigned long long	file_pos;
+	unsigned long long	size;
 } file_state_t;
 
 static file_state_t current_file = {0};
@@ -44,7 +44,7 @@
 static int memmap_block_open(io_dev_info_t *dev_info, const uintptr_t spec,
 			     io_entity_t *entity);
 static int memmap_block_seek(io_entity_t *entity, int mode,
-			     ssize_t offset);
+			     signed long long offset);
 static int memmap_block_len(io_entity_t *entity, size_t *length);
 static int memmap_block_read(io_entity_t *entity, uintptr_t buffer,
 			     size_t length, size_t *length_read);
@@ -131,7 +131,8 @@
 
 
 /* Seek to a particular file offset on the memmap device */
-static int memmap_block_seek(io_entity_t *entity, int mode, ssize_t offset)
+static int memmap_block_seek(io_entity_t *entity, int mode,
+			     signed long long offset)
 {
 	int result = -ENOENT;
 	file_state_t *fp;
@@ -143,7 +144,8 @@
 		fp = (file_state_t *) entity->info;
 
 		/* Assert that new file position is valid */
-		assert((offset >= 0) && (offset < fp->size));
+		assert((offset >= 0) &&
+		       ((unsigned long long)offset < fp->size));
 
 		/* Reset file position */
 		fp->file_pos = offset;
@@ -171,7 +173,7 @@
 			     size_t length, size_t *length_read)
 {
 	file_state_t *fp;
-	size_t pos_after;
+	unsigned long long pos_after;
 
 	assert(entity != NULL);
 	assert(length_read != NULL);
@@ -198,7 +200,7 @@
 			      size_t length, size_t *length_written)
 {
 	file_state_t *fp;
-	size_t pos_after;
+	unsigned long long pos_after;
 
 	assert(entity != NULL);
 	assert(length_written != NULL);
diff --git a/drivers/io/io_block.c b/drivers/io/io_block.c
index f190a43..5d45c2f 100644
--- a/drivers/io/io_block.c
+++ b/drivers/io/io_block.c
@@ -19,17 +19,17 @@
 typedef struct {
 	io_block_dev_spec_t	*dev_spec;
 	uintptr_t		base;
-	size_t			file_pos;
-	size_t			size;
+	unsigned long long	file_pos;
+	unsigned long long	size;
 } block_dev_state_t;
 
-#define is_power_of_2(x)	((x != 0) && ((x & (x - 1)) == 0))
+#define is_power_of_2(x)	(((x) != 0U) && (((x) & ((x) - 1U)) == 0U))
 
 io_type_t device_type_block(void);
 
 static int block_open(io_dev_info_t *dev_info, const uintptr_t spec,
 		      io_entity_t *entity);
-static int block_seek(io_entity_t *entity, int mode, ssize_t offset);
+static int block_seek(io_entity_t *entity, int mode, signed long long offset);
 static int block_read(io_entity_t *entity, uintptr_t buffer, size_t length,
 		      size_t *length_read);
 static int block_write(io_entity_t *entity, const uintptr_t buffer,
@@ -148,21 +148,21 @@
 }
 
 /* parameter offset is relative address at here */
-static int block_seek(io_entity_t *entity, int mode, ssize_t offset)
+static int block_seek(io_entity_t *entity, int mode, signed long long offset)
 {
 	block_dev_state_t *cur;
 
 	assert(entity->info != (uintptr_t)NULL);
 
 	cur = (block_dev_state_t *)entity->info;
-	assert((offset >= 0) && (offset < cur->size));
+	assert((offset >= 0) && ((unsigned long long)offset < cur->size));
 
 	switch (mode) {
 	case IO_SEEK_SET:
-		cur->file_pos = offset;
+		cur->file_pos = (unsigned long long)offset;
 		break;
 	case IO_SEEK_CUR:
-		cur->file_pos += offset;
+		cur->file_pos += (unsigned long long)offset;
 		break;
 	default:
 		return -EINVAL;
@@ -270,7 +270,7 @@
 	buf = &(cur->dev_spec->buffer);
 	block_size = cur->dev_spec->block_size;
 	assert((length <= cur->size) &&
-	       (length > 0) &&
+	       (length > 0U) &&
 	       (ops->read != 0));
 
 	/*
@@ -279,7 +279,7 @@
 	 * on the low level driver.
 	 */
 	count = 0;
-	for (left = length; left > 0; left -= nbytes) {
+	for (left = length; left > 0U; left -= nbytes) {
 		/*
 		 * We must only request operations aligned to the block
 		 * size. Therefore if file_pos is not block-aligned,
@@ -288,7 +288,7 @@
 		 * similarly, the number of bytes requested must be a
 		 * block size multiple
 		 */
-		skip = cur->file_pos & (block_size - 1);
+		skip = cur->file_pos & (block_size - 1U);
 
 		/*
 		 * Calculate the block number containing file_pos
@@ -296,7 +296,7 @@
 		 */
 		lba = (cur->file_pos + cur->base) / block_size;
 
-		if (skip + left > buf->length) {
+		if ((skip + left) > buf->length) {
 			/*
 			 * The underlying read buffer is too small to
 			 * read all the required data - limit to just
@@ -311,7 +311,8 @@
 			 * block size.
 			 */
 			request = skip + left;
-			request = (request + (block_size - 1)) & ~(block_size - 1);
+			request = (request + (block_size - 1U)) &
+				~(block_size - 1U);
 		}
 		request = ops->read(lba, buf->offset, request);
 
@@ -330,7 +331,7 @@
 		 * the read data when copying to the user buffer.
 		 */
 		nbytes = request - skip;
-		padding = (nbytes > left) ? nbytes - left : 0;
+		padding = (nbytes > left) ? nbytes - left : 0U;
 		nbytes -= padding;
 
 		memcpy((void *)(buffer + count),
@@ -381,7 +382,7 @@
 	buf = &(cur->dev_spec->buffer);
 	block_size = cur->dev_spec->block_size;
 	assert((length <= cur->size) &&
-	       (length > 0) &&
+	       (length > 0U) &&
 	       (ops->read != 0) &&
 	       (ops->write != 0));
 
@@ -391,7 +392,7 @@
 	 * on the low level driver.
 	 */
 	count = 0;
-	for (left = length; left > 0; left -= nbytes) {
+	for (left = length; left > 0U; left -= nbytes) {
 		/*
 		 * We must only request operations aligned to the block
 		 * size. Therefore if file_pos is not block-aligned,
@@ -400,7 +401,7 @@
 		 * similarly, the number of bytes requested must be a
 		 * block size multiple
 		 */
-		skip = cur->file_pos & (block_size - 1);
+		skip = cur->file_pos & (block_size - 1U);
 
 		/*
 		 * Calculate the block number containing file_pos
@@ -408,7 +409,7 @@
 		 */
 		lba = (cur->file_pos + cur->base) / block_size;
 
-		if (skip + left > buf->length) {
+		if ((skip + left) > buf->length) {
 			/*
 			 * The underlying read buffer is too small to
 			 * read all the required data - limit to just
@@ -423,7 +424,8 @@
 			 * block size.
 			 */
 			request = skip + left;
-			request = (request + (block_size - 1)) & ~(block_size - 1);
+			request = (request + (block_size - 1U)) &
+				~(block_size - 1U);
 		}
 
 		/*
@@ -432,7 +434,7 @@
 		 * of the current request.
 		 */
 		nbytes = request - skip;
-		padding = (nbytes > left) ? nbytes - left : 0;
+		padding = (nbytes > left) ? nbytes - left : 0U;
 		nbytes -= padding;
 
 		/*
@@ -440,14 +442,14 @@
 		 * some content and it means that we have to read before
 		 * writing
 		 */
-		if (skip > 0 || padding > 0) {
+		if ((skip > 0U) || (padding > 0U)) {
 			request = ops->read(lba, buf->offset, request);
 			/*
 			 * The read may return size less than
 			 * requested. Round down to the nearest block
 			 * boundary
 			 */
-			request &= ~(block_size-1);
+			request &= ~(block_size - 1U);
 			if (request <= skip) {
 				/*
 				 * We couldn't read enough bytes to jump over
@@ -458,7 +460,7 @@
 				return -EIO;
 			}
 			nbytes = request - skip;
-			padding = (nbytes > left) ? nbytes - left : 0;
+			padding = (nbytes > left) ? nbytes - left : 0U;
 			nbytes -= padding;
 		}
 
@@ -477,7 +479,7 @@
 		 * buffer
 		 */
 		nbytes = request - skip;
-		padding = (nbytes > left) ? nbytes - left : 0;
+		padding = (nbytes > left) ? nbytes - left : 0U;
 		nbytes -= padding;
 
 		cur->file_pos += nbytes;
@@ -505,7 +507,7 @@
 
 	assert(dev_info != NULL);
 	result = allocate_dev_info(&info);
-	if (result)
+	if (result != 0)
 		return -ENOENT;
 
 	cur = (block_dev_state_t *)info->info;
@@ -513,10 +515,10 @@
 	cur->dev_spec = (io_block_dev_spec_t *)dev_spec;
 	buffer = &(cur->dev_spec->buffer);
 	block_size = cur->dev_spec->block_size;
-	assert((block_size > 0) &&
-	       (is_power_of_2(block_size) != 0) &&
-	       ((buffer->offset % block_size) == 0) &&
-	       ((buffer->length % block_size) == 0));
+	assert((block_size > 0U) &&
+	       (is_power_of_2(block_size) != 0U) &&
+	       ((buffer->offset % block_size) == 0U) &&
+	       ((buffer->length % block_size) == 0U));
 
 	*dev_info = info;	/* cast away const */
 	(void)block_size;
diff --git a/drivers/io/io_fip.c b/drivers/io/io_fip.c
index 544b37d..5d49fff 100644
--- a/drivers/io/io_fip.c
+++ b/drivers/io/io_fip.c
@@ -304,7 +304,8 @@
 	}
 
 	/* Seek past the FIP header into the Table of Contents */
-	result = io_seek(backend_handle, IO_SEEK_SET, sizeof(fip_toc_header_t));
+	result = io_seek(backend_handle, IO_SEEK_SET,
+			 (signed long long)sizeof(fip_toc_header_t));
 	if (result != 0) {
 		WARN("fip_file_open: failed to seek\n");
 		result = -ENOENT;
@@ -389,7 +390,8 @@
 
 	/* Seek to the position in the FIP where the payload lives */
 	file_offset = fp->entry.offset_address + fp->file_pos;
-	result = io_seek(backend_handle, IO_SEEK_SET, file_offset);
+	result = io_seek(backend_handle, IO_SEEK_SET,
+			 (signed long long)file_offset);
 	if (result != 0) {
 		WARN("fip_file_read: failed to seek\n");
 		result = -ENOENT;
diff --git a/drivers/io/io_memmap.c b/drivers/io/io_memmap.c
index 96590b6..eed50cc 100644
--- a/drivers/io/io_memmap.c
+++ b/drivers/io/io_memmap.c
@@ -23,10 +23,10 @@
 	/* Use the 'in_use' flag as any value for base and file_pos could be
 	 * valid.
 	 */
-	int		in_use;
-	uintptr_t	base;
-	size_t		file_pos;
-	size_t		size;
+	int			in_use;
+	uintptr_t		base;
+	unsigned long long	file_pos;
+	unsigned long long	size;
 } file_state_t;
 
 static file_state_t current_file = {0};
@@ -42,7 +42,7 @@
 static int memmap_block_open(io_dev_info_t *dev_info, const uintptr_t spec,
 			     io_entity_t *entity);
 static int memmap_block_seek(io_entity_t *entity, int mode,
-			     ssize_t offset);
+			     signed long long offset);
 static int memmap_block_len(io_entity_t *entity, size_t *length);
 static int memmap_block_read(io_entity_t *entity, uintptr_t buffer,
 			     size_t length, size_t *length_read);
@@ -129,7 +129,8 @@
 
 
 /* Seek to a particular file offset on the memmap device */
-static int memmap_block_seek(io_entity_t *entity, int mode, ssize_t offset)
+static int memmap_block_seek(io_entity_t *entity, int mode,
+			     signed long long offset)
 {
 	int result = -ENOENT;
 	file_state_t *fp;
@@ -141,10 +142,11 @@
 		fp = (file_state_t *) entity->info;
 
 		/* Assert that new file position is valid */
-		assert((offset >= 0) && (offset < fp->size));
+		assert((offset >= 0) &&
+		       ((unsigned long long)offset < fp->size));
 
 		/* Reset file position */
-		fp->file_pos = offset;
+		fp->file_pos = (unsigned long long)offset;
 		result = 0;
 	}
 
@@ -158,7 +160,7 @@
 	assert(entity != NULL);
 	assert(length != NULL);
 
-	*length = ((file_state_t *)entity->info)->size;
+	*length = (size_t)((file_state_t *)entity->info)->size;
 
 	return 0;
 }
@@ -169,7 +171,7 @@
 			     size_t length, size_t *length_read)
 {
 	file_state_t *fp;
-	size_t pos_after;
+	unsigned long long pos_after;
 
 	assert(entity != NULL);
 	assert(length_read != NULL);
@@ -180,7 +182,8 @@
 	pos_after = fp->file_pos + length;
 	assert((pos_after >= fp->file_pos) && (pos_after <= fp->size));
 
-	memcpy((void *)buffer, (void *)(fp->base + fp->file_pos), length);
+	memcpy((void *)buffer,
+	       (void *)((uintptr_t)(fp->base + fp->file_pos)), length);
 
 	*length_read = length;
 
@@ -196,7 +199,7 @@
 			      size_t length, size_t *length_written)
 {
 	file_state_t *fp;
-	size_t pos_after;
+	unsigned long long pos_after;
 
 	assert(entity != NULL);
 	assert(length_written != NULL);
@@ -207,7 +210,8 @@
 	pos_after = fp->file_pos + length;
 	assert((pos_after >= fp->file_pos) && (pos_after <= fp->size));
 
-	memcpy((void *)(fp->base + fp->file_pos), (void *)buffer, length);
+	memcpy((void *)((uintptr_t)(fp->base + fp->file_pos)),
+	       (void *)buffer, length);
 
 	*length_written = length;
 
diff --git a/drivers/io/io_semihosting.c b/drivers/io/io_semihosting.c
index 23d09c1..4ceddc6 100644
--- a/drivers/io/io_semihosting.c
+++ b/drivers/io/io_semihosting.c
@@ -25,7 +25,7 @@
 static int sh_dev_open(const uintptr_t dev_spec, io_dev_info_t **dev_info);
 static int sh_file_open(io_dev_info_t *dev_info, const uintptr_t spec,
 		io_entity_t *entity);
-static int sh_file_seek(io_entity_t *entity, int mode, ssize_t offset);
+static int sh_file_seek(io_entity_t *entity, int mode, signed long long offset);
 static int sh_file_len(io_entity_t *entity, size_t *length);
 static int sh_file_read(io_entity_t *entity, uintptr_t buffer, size_t length,
 		size_t *length_read);
@@ -90,7 +90,7 @@
 
 
 /* Seek to a particular file offset on the semi-hosting device */
-static int sh_file_seek(io_entity_t *entity, int mode, ssize_t offset)
+static int sh_file_seek(io_entity_t *entity, int mode, signed long long offset)
 {
 	long file_handle, sh_result;
 
@@ -98,7 +98,7 @@
 
 	file_handle = (long)entity->info;
 
-	sh_result = semihosting_file_seek(file_handle, offset);
+	sh_result = semihosting_file_seek(file_handle, (ssize_t)offset);
 
 	return (sh_result == 0) ? 0 : -ENOENT;
 }
diff --git a/drivers/io/io_storage.c b/drivers/io/io_storage.c
index e444f87..b8c1d64 100644
--- a/drivers/io/io_storage.c
+++ b/drivers/io/io_storage.c
@@ -237,7 +237,7 @@
 
 
 /* Seek to a specific position in an IO entity */
-int io_seek(uintptr_t handle, io_seek_mode_t mode, ssize_t offset)
+int io_seek(uintptr_t handle, io_seek_mode_t mode, signed long long offset)
 {
 	int result = -ENODEV;
 	assert(is_valid_entity(handle) && is_valid_seek_mode(mode));
diff --git a/drivers/renesas/rcar/io/io_emmcdrv.c b/drivers/renesas/rcar/io/io_emmcdrv.c
index 4b464fb..84240d2 100644
--- a/drivers/renesas/rcar/io/io_emmcdrv.c
+++ b/drivers/renesas/rcar/io/io_emmcdrv.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2017, Renesas Electronics Corporation. All rights reserved.
+ * Copyright (c) 2015-2019, Renesas Electronics Corporation. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -25,7 +25,7 @@
 typedef struct {
 	uint32_t in_use;
 	uintptr_t base;
-	ssize_t file_pos;
+	signed long long file_pos;
 	EMMC_PARTITION_ID partition;
 } file_state_t;
 
@@ -39,7 +39,7 @@
 }
 
 static int32_t emmcdrv_block_seek(io_entity_t *entity, int32_t mode,
-				  ssize_t offset)
+				  signed long long offset)
 {
 	if (mode != IO_SEEK_SET)
 		return IO_FAIL;
@@ -59,12 +59,12 @@
 	sector_add = current_file.file_pos >> EMMC_SECTOR_SIZE_SHIFT;
 	sector_num = (length + EMMC_SECTOR_SIZE - 1U) >> EMMC_SECTOR_SIZE_SHIFT;
 
-	NOTICE("BL2: Load dst=0x%lx src=(p:%d)0x%lx(%d) len=0x%lx(%d)\n",
+	NOTICE("BL2: Load dst=0x%lx src=(p:%d)0x%llx(%d) len=0x%lx(%d)\n",
 	       buffer,
 	       current_file.partition, current_file.file_pos,
 	       sector_add, length, sector_num);
 
-	if (buffer + length - 1 <= UINT32_MAX)
+	if ((buffer + length - 1U) <= (uintptr_t)UINT32_MAX)
 		emmc_dma = LOADIMAGE_FLAGS_DMA_ENABLE;
 
 	if (emmc_read_sector((uint32_t *) buffer, sector_add, sector_num,
@@ -72,7 +72,7 @@
 		result = IO_FAIL;
 
 	*length_read = length;
-	fp->file_pos += length;
+	fp->file_pos += (signed long long)length;
 
 	return result;
 }
@@ -82,7 +82,7 @@
 {
 	const io_drv_spec_t *block_spec = (io_drv_spec_t *) spec;
 
-	if (current_file.in_use) {
+	if (current_file.in_use != 0U) {
 		WARN("mmc_block: Only one open spec at a time\n");
 		return IO_RESOURCES_EXHAUSTED;
 	}
@@ -103,9 +103,9 @@
 		return IO_FAIL;
 	}
 
-	if (PARTITION_ID_USER == block_spec->partition ||
-	    PARTITION_ID_BOOT_1 == block_spec->partition ||
-	    PARTITION_ID_BOOT_2 == block_spec->partition)
+	if ((PARTITION_ID_USER == block_spec->partition) ||
+	    (PARTITION_ID_BOOT_1 == block_spec->partition) ||
+	    (PARTITION_ID_BOOT_2 == block_spec->partition))
 		current_file.partition = block_spec->partition;
 	else
 		current_file.partition = emmcdrv_bootpartition;
diff --git a/drivers/renesas/rcar/io/io_memdrv.c b/drivers/renesas/rcar/io/io_memdrv.c
index 3f6b4c7..7e8c1d3 100644
--- a/drivers/renesas/rcar/io/io_memdrv.c
+++ b/drivers/renesas/rcar/io/io_memdrv.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2018, Renesas Electronics Corporation. All rights reserved.
+ * Copyright (c) 2015-2019, Renesas Electronics Corporation. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -28,7 +28,7 @@
 typedef struct {
 	uint32_t in_use;
 	uintptr_t base;
-	ssize_t file_pos;
+	signed long long file_pos;
 } file_state_t;
 
 static file_state_t current_file = { 0 };
@@ -47,7 +47,7 @@
 	 * spec at a time. When we have dynamic memory we can malloc and set
 	 * entity->info.
 	 */
-	if (current_file.in_use)
+	if (current_file.in_use != 0U)
 		return IO_RESOURCES_EXHAUSTED;
 
 	/* File cursor offset for seek and incremental reads etc. */
@@ -61,7 +61,7 @@
 }
 
 static int32_t memdrv_block_seek(io_entity_t *entity, int32_t mode,
-				 ssize_t offset)
+				 signed long long offset)
 {
 	if (mode != IO_SEEK_SET)
 		return IO_FAIL;
@@ -78,16 +78,17 @@
 
 	fp = (file_state_t *) entity->info;
 
-	NOTICE("BL2: dst=0x%lx src=0x%lx len=%ld(0x%lx)\n",
-	       buffer, fp->base + fp->file_pos, length, length);
+	NOTICE("BL2: dst=0x%lx src=0x%llx len=%ld(0x%lx)\n",
+	       buffer, (unsigned long long)fp->base +
+	       (unsigned long long)fp->file_pos, length, length);
 
-	if (FLASH_MEMORY_SIZE < fp->file_pos + length) {
+	if (FLASH_MEMORY_SIZE < (fp->file_pos + (signed long long)length)) {
 		ERROR("BL2: check load image (source address)\n");
 		return IO_FAIL;
 	}
 
-	rcar_dma_exec(buffer, fp->base + fp->file_pos, length);
-	fp->file_pos += length;
+	rcar_dma_exec(buffer, fp->base + (uintptr_t)fp->file_pos, length);
+	fp->file_pos += (signed long long)length;
 	*cnt = length;
 
 	return IO_SUCCESS;
diff --git a/drivers/st/io/io_mmc.c b/drivers/st/io/io_mmc.c
index a239b5f..44b7d19 100644
--- a/drivers/st/io/io_mmc.c
+++ b/drivers/st/io/io_mmc.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -20,14 +20,15 @@
 static int mmc_block_open(io_dev_info_t *dev_info, const uintptr_t spec,
 			  io_entity_t *entity);
 static int mmc_dev_init(io_dev_info_t *dev_info, const uintptr_t init_params);
-static int mmc_block_seek(io_entity_t *entity, int mode, ssize_t offset);
+static int mmc_block_seek(io_entity_t *entity, int mode,
+			  signed long long offset);
 static int mmc_block_read(io_entity_t *entity, uintptr_t buffer, size_t length,
 			  size_t *length_read);
 static int mmc_block_close(io_entity_t *entity);
 static int mmc_dev_close(io_dev_info_t *dev_info);
 static io_type_t device_type_mmc(void);
 
-static ssize_t seek_offset;
+static signed long long seek_offset;
 
 static const io_dev_connector_t mmc_dev_connector = {
 	.dev_open = mmc_dev_open
@@ -85,7 +86,8 @@
 }
 
 /* Seek to a particular file offset on the mmc device */
-static int mmc_block_seek(io_entity_t *entity, int mode, ssize_t offset)
+static int mmc_block_seek(io_entity_t *entity, int mode,
+			  signed long long offset)
 {
 	seek_offset = offset;
 	return 0;