path: root/drivers/soc/qcom/smem.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2015, Sony Mobile Communications AB.
 * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
 */

#include <linux/hwspinlock.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_reserved_mem.h>
#include <linux/platform_device.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/soc/qcom/smem.h>
#include <linux/soc/qcom/socinfo.h>

/*
 * The Qualcomm shared memory system is a allocate only heap structure that
 * consists of one of more memory areas that can be accessed by the processors
 * in the SoC.
 *
 * All systems contains a global heap, accessible by all processors in the SoC,
 * with a table of contents data structure (@smem_header) at the beginning of
 * the main shared memory block.
 *
 * The global header contains meta data for allocations as well as a fixed list
 * of 512 entries (@smem_global_entry) that can be initialized to reference
 * parts of the shared memory space.
 *
 *
 * In addition to this global heap a set of "private" heaps can be set up at
 * boot time with access restrictions so that only certain processor pairs can
 * access the data.
 *
 * These partitions are referenced from an optional partition table
 * (@smem_ptable), that is found 4kB from the end of the main smem region. The
 * partition table entries (@smem_ptable_entry) lists the involved processors
 * (or hosts) and their location in the main shared memory region.
 *
 * Each partition starts with a header (@smem_partition_header) that identifies
 * the partition and holds properties for the two internal memory regions. The
 * two regions are cached and non-cached memory respectively. Each region
 * contain a link list of allocation headers (@smem_private_entry) followed by
 * their data.
 *
 * Items in the non-cached region are allocated from the start of the partition
 * while items in the cached region are allocated from the end. The free area
 * is hence the region between the cached and non-cached offsets. The header of
 * cached items comes after the data.
 *
 * Version 12 (SMEM_GLOBAL_PART_VERSION) changes the item alloc/get procedure
 * for the global heap. A new global partition is created from the global heap
 * region with partition type (SMEM_GLOBAL_HOST) and the max smem item count is
 * set by the bootloader.
 *
 * To synchronize allocations in the shared memory heaps a remote spinlock must
 * be held - currently lock number 3 of the sfpb or tcsr is used for this on all
 * platforms.
 *
 */

/*
 * The version member of the smem header contains an array of versions for the
 * various software components in the SoC. We verify that the boot loader
 * version is a valid version as a sanity check.
 */
#define SMEM_MASTER_SBL_VERSION_INDEX	7
#define SMEM_GLOBAL_HEAP_VERSION	11
#define SMEM_GLOBAL_PART_VERSION	12

/*
 * The first 8 items are only to be allocated by the boot loader while
 * initializing the heap.
 */
#define SMEM_ITEM_LAST_FIXED	8

/* Highest accepted item number, for both global and private heaps */
#define SMEM_ITEM_COUNT		512

/* Processor/host identifier for the application processor */
#define SMEM_HOST_APPS		0

/* Processor/host identifier for the global partition */
#define SMEM_GLOBAL_HOST	0xfffe

/* Max number of processors/hosts in a system */
#define SMEM_HOST_COUNT		20

/**
  * struct smem_proc_comm - proc_comm communication struct (legacy)
  * @command:	current command to be executed
  * @status:	status of the currently requested command
  * @params:	parameters to the command
  */
struct smem_proc_comm {
	__le32 command;
	__le32 status;
	__le32 params[2];
};

/**
 * struct smem_global_entry - entry to reference smem items on the heap
 * @allocated:	boolean to indicate if this entry is used
 * @offset:	offset to the allocated space
 * @size:	size of the allocated space, 8 byte aligned
 * @aux_base:	base address for the memory region used by this unit, or 0 for
 *		the default region. bits 0,1 are reserved
 */
struct smem_global_entry {
	__le32 allocated;
	__le32 offset;
	__le32 size;
	__le32 aux_base; /* bits 1:0 reserved */
};
#define AUX_BASE_MASK		0xfffffffc

/**
 * struct smem_header - header found in beginning of primary smem region
 * @proc_comm:		proc_comm communication interface (legacy)
 * @version:		array of versions for the various subsystems
 * @initialized:	boolean to indicate that smem is initialized
 * @free_offset:	index of the first unallocated byte in smem
 * @available:		number of bytes available for allocation
 * @reserved:		reserved field, must be 0
 * @toc:		array of references to items
 */
struct smem_header {
	struct smem_proc_comm proc_comm[4];
	__le32 version[32];
	__le32 initialized;
	__le32 free_offset;
	__le32 available;
	__le32 reserved;
	struct smem_global_entry toc[SMEM_ITEM_COUNT];
};

/**
 * struct smem_ptable_entry - one entry in the @smem_ptable list
 * @offset:	offset, within the main shared memory region, of the partition
 * @size:	size of the partition
 * @flags:	flags for the partition (currently unused)
 * @host0:	first processor/host with access to this partition
 * @host1:	second processor/host with access to this partition
 * @cacheline:	alignment for "cached" entries
 * @reserved:	reserved entries for later use
 */
struct smem_ptable_entry {
	__le32 offset;
	__le32 size;
	__le32 flags;
	__le16 host0;
	__le16 host1;
	__le32 cacheline;
	__le32 reserved[7];
};

/**
 * struct smem_ptable - partition table for the private partitions
 * @magic:	magic number, must be SMEM_PTABLE_MAGIC
 * @version:	version of the partition table
 * @num_entries: number of partitions in the table
 * @reserved:	for now reserved entries
 * @entry:	list of @smem_ptable_entry for the @num_entries partitions
 */
struct smem_ptable {
	u8 magic[4];
	__le32 version;
	__le32 num_entries;
	__le32 reserved[5];
	struct smem_ptable_entry entry[];
};

static const u8 SMEM_PTABLE_MAGIC[] = { 0x24, 0x54, 0x4f, 0x43 }; /* "$TOC" */

/**
 * struct smem_partition_header - header of the partitions
 * @magic:	magic number, must be SMEM_PART_MAGIC
 * @host0:	first processor/host with access to this part