SDS: Introduce the sds drivers
This patch introduces the driver for Shared-Data-Structure (SDS)
framework which will be used for communication between SCP and AP
CPU. The SDS framework is intended to replace the Boot-Over-MHU
(BOM) protocol used currently for the communication
Change-Id: Ic174291121f4e581b174cce3389d22d6435f7269
Signed-off-by: Soby Mathew <soby.mathew@arm.com>
diff --git a/plat/arm/css/drivers/sds/sds.c b/plat/arm/css/drivers/sds/sds.c
new file mode 100644
index 0000000..e2fac54
--- /dev/null
+++ b/plat/arm/css/drivers/sds/sds.c
@@ -0,0 +1,258 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch_helpers.h>
+#include <assert.h>
+#include <debug.h>
+#include <css_def.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "sds.h"
+#include "sds_private.h"
+
+/*
+ * Variables used to track and maintain the state of the memory region reserved
+ * for usage by the SDS framework.
+ */
+
+/* Pointer to the base of the SDS memory region */
+static uintptr_t sds_mem_base;
+
+/* Size of the SDS memory region in bytes */
+static size_t sds_mem_size;
+
+/*
+ * Perform some non-exhaustive tests to determine whether any of the fields
+ * within a Structure Header contain obviously invalid data.
+ * Returns SDS_OK on success, SDS_ERR_FAIL on error.
+ */
+static int sds_struct_is_valid(uintptr_t header)
+{
+ size_t struct_size = GET_SDS_HEADER_STRUCT_SIZE(header);
+
+ /* Zero is not a valid identifier */
+ if (GET_SDS_HEADER_ID(header) == 0)
+ return SDS_ERR_FAIL;
+
+ /* Check SDS Schema version */
+ if (GET_SDS_HEADER_VERSION(header) == SDS_REGION_SCH_VERSION)
+ return SDS_ERR_FAIL;
+
+ /* The SDS Structure sizes have to be multiple of 8 */
+ if ((struct_size == 0) || ((struct_size % 8) != 0))
+ return SDS_ERR_FAIL;
+
+ if (struct_size > sds_mem_size)
+ return SDS_ERR_FAIL;
+
+ return SDS_OK;
+}
+
+/*
+ * Validate the SDS structure headers.
+ * Returns SDS_OK on success, SDS_ERR_FAIL on error.
+ */
+static int validate_sds_struct_headers(void)
+{
+ unsigned int i, structure_count;
+ uintptr_t header;
+
+ structure_count = GET_SDS_REGION_STRUCTURE_COUNT(sds_mem_base);
+
+ if (structure_count == 0)
+ return SDS_ERR_FAIL;
+
+ header = sds_mem_base + SDS_REGION_DESC_SIZE;
+
+ /* Iterate over structure headers and validate each one */
+ for (i = 0; i < structure_count; i++) {
+ if (sds_struct_is_valid(header) != SDS_OK) {
+ WARN("SDS: Invalid structure header detected\n");
+ return SDS_ERR_FAIL;
+ }
+ header += GET_SDS_HEADER_STRUCT_SIZE(header) + SDS_HEADER_SIZE;
+ }
+ return SDS_OK;
+}
+
+/*
+ * Get the structure header pointer corresponding to the structure ID.
+ * Returns SDS_OK on success, SDS_ERR_STRUCT_NOT_FOUND on error.
+ */
+static int get_struct_header(uint32_t structure_id, struct_header_t **header)
+{
+ unsigned int i, structure_count;
+ uintptr_t current_header;
+
+ assert(header);
+
+ structure_count = GET_SDS_REGION_STRUCTURE_COUNT(sds_mem_base);
+ if (structure_count == 0)
+ return SDS_ERR_STRUCT_NOT_FOUND;
+
+ current_header = ((uintptr_t)sds_mem_base) + SDS_REGION_DESC_SIZE;
+
+ /* Iterate over structure headers to find one with a matching ID */
+ for (i = 0; i < structure_count; i++) {
+ if (GET_SDS_HEADER_ID(current_header) == structure_id) {
+ *header = (struct_header_t *)current_header;
+ return SDS_OK;
+ }
+ current_header += GET_SDS_HEADER_STRUCT_SIZE(current_header) +
+ SDS_HEADER_SIZE;
+ }
+
+ *header = NULL;
+ return SDS_ERR_STRUCT_NOT_FOUND;
+}
+
+/*
+ * Check if a structure header corresponding to the structure ID exists.
+ * Returns SDS_OK if structure header exists else SDS_ERR_STRUCT_NOT_FOUND
+ * if not found.
+ */
+int sds_struct_exists(unsigned int structure_id)
+{
+ struct_header_t *header = NULL;
+ int ret;
+
+ ret = get_struct_header(structure_id, &header);
+ if (ret == SDS_OK) {
+ assert(header);
+ }
+
+ return ret;
+}
+
+/*
+ * Read from field in the structure corresponding to `structure_id`.
+ * `fld_off` is the offset to the field in the structure and `mode`
+ * indicates whether cache maintenance need to performed prior to the read.
+ * The `data` is the pointer to store the read data of size specified by `size`.
+ * Returns SDS_OK on success or corresponding error codes on failure.
+ */
+int sds_struct_read(uint32_t structure_id, unsigned int fld_off,
+ void *data, size_t size, sds_access_mode_t mode)
+{
+ int status;
+ uintptr_t field_base;
+ struct_header_t *header = NULL;
+
+ if (!data)
+ return SDS_ERR_INVALID_PARAMS;
+
+ /* Check if a structure with this ID exists */
+ status = get_struct_header(structure_id, &header);
+ if (status != SDS_OK)
+ return status;
+
+ assert(header);
+
+ if (mode == SDS_ACCESS_MODE_CACHED)
+ inv_dcache_range((uintptr_t)header, SDS_HEADER_SIZE + size);
+
+ if (!IS_SDS_HEADER_VALID(header)) {
+ WARN("SDS: Reading from un-finalized structure 0x%x\n",
+ structure_id);
+ return SDS_ERR_STRUCT_NOT_FINALIZED;
+ }
+
+ if ((fld_off + size) > GET_SDS_HEADER_STRUCT_SIZE(header))
+ return SDS_ERR_FAIL;
+
+ field_base = (uintptr_t)header + SDS_HEADER_SIZE + fld_off;
+ if (check_uptr_overflow(field_base, size - 1))
+ return SDS_ERR_FAIL;
+
+ /* Copy the required field in the struct */
+ memcpy(data, (void *)field_base, size);
+
+ return SDS_OK;
+}
+
+/*
+ * Write to the field in the structure corresponding to `structure_id`.
+ * `fld_off` is the offset to the field in the structure and `mode`
+ * indicates whether cache maintenance need to performed for the write.
+ * The `data` is the pointer to data of size specified by `size`.
+ * Returns SDS_OK on success or corresponding error codes on failure.
+ */
+int sds_struct_write(uint32_t structure_id, unsigned int fld_off,
+ void *data, size_t size, sds_access_mode_t mode)
+{
+ int status;
+ uintptr_t field_base;
+ struct_header_t *header = NULL;
+
+ if (!data)
+ return SDS_ERR_INVALID_PARAMS;
+
+ /* Check if a structure with this ID exists */
+ status = get_struct_header(structure_id, &header);
+ if (status != SDS_OK)
+ return status;
+
+ assert(header);
+
+ if (mode == SDS_ACCESS_MODE_CACHED)
+ inv_dcache_range((uintptr_t)header, SDS_HEADER_SIZE + size);
+
+ if (!IS_SDS_HEADER_VALID(header)) {
+ WARN("SDS: Writing to un-finalized structure 0x%x\n",
+ structure_id);
+ return SDS_ERR_STRUCT_NOT_FINALIZED;
+ }
+
+ if ((fld_off + size) > GET_SDS_HEADER_STRUCT_SIZE(header))
+ return SDS_ERR_FAIL;
+
+ field_base = (uintptr_t)header + SDS_HEADER_SIZE + fld_off;
+ if (check_uptr_overflow(field_base, size - 1))
+ return SDS_ERR_FAIL;
+
+ /* Copy the required field in the struct */
+ memcpy((void *)field_base, data, size);
+
+ if (mode == SDS_ACCESS_MODE_CACHED)
+ flush_dcache_range((uintptr_t)field_base, size);
+
+ return SDS_OK;
+}
+
+/*
+ * Initialize the SDS driver. Also verifies the SDS version and sanity of
+ * the SDS structure headers.
+ * Returns SDS_OK on success, SDS_ERR_FAIL on error.
+ */
+int sds_init(void)
+{
+ sds_mem_base = (uintptr_t)PLAT_ARM_SDS_MEM_BASE;
+
+ if (!IS_SDS_REGION_VALID(sds_mem_base)) {
+ WARN("SDS: No valid SDS Memory Region found\n");
+ return SDS_ERR_FAIL;
+ }
+
+ if (GET_SDS_REGION_SCHEMA_VERSION(sds_mem_base)
+ != SDS_REGION_SCH_VERSION) {
+ WARN("SDS: Unsupported SDS schema version\n");
+ return SDS_ERR_FAIL;
+ }
+
+ sds_mem_size = GET_SDS_REGION_SIZE(sds_mem_base);
+ if (sds_mem_size > PLAT_ARM_SDS_MEM_SIZE_MAX) {
+ WARN("SDS: SDS Memory Region exceeds size limit\n");
+ return SDS_ERR_FAIL;
+ }
+
+ INFO("SDS: Detected SDS Memory Region (%zu bytes)\n", sds_mem_size);
+
+ if (validate_sds_struct_headers() != SDS_OK)
+ return SDS_ERR_FAIL;
+
+ return SDS_OK;
+}