path: root/mali_pixel/memory_group_manager.c

// SPDX-License-Identifier: GPL-2.0
/*
 * memory_group_manager.c
 *
 * C) COPYRIGHT 2019 ARM Limited. All rights reserved.
 * C) COPYRIGHT 2019-2020 Google LLC
 *
 */

/* Turn this on for more debug */
//#define DEBUG

#include <linux/fs.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/version.h>
#include <linux/module.h>
#include <linux/atomic.h>
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>
#endif
#include <linux/mm.h>
#include <linux/memory_group_manager.h>

#include <soc/google/pt.h>

#define PBHA_BIT_POS  (36)
#define PBHA_BIT_MASK (0xf)

#define MGM_PBHA_DEFAULT 0
#define GROUP_ID_TO_PT_IDX(x) ((x)-1)

/* The Mali driver requires that allocations made on one of the groups
 * are not treated specially.
 */
#define MGM_RESERVED_GROUP_ID 0

/* Imported memory is handled by the allocator of the memory, and the Mali
 * DDK will request a group_id for such memory via mgm_get_import_memory_id().
 * We specify which group we want to use for this here.
 */
#define MGM_IMPORTED_MEMORY_GROUP_ID (MEMORY_GROUP_MANAGER_NR_GROUPS - 1)


#define INVALID_GROUP_ID(group_id) \
	(WARN_ON((group_id) < 0) || \
	WARN_ON((group_id) >= MEMORY_GROUP_MANAGER_NR_GROUPS))

#if (KERNEL_VERSION(4, 20, 0) > LINUX_VERSION_CODE)
static inline vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma,
			unsigned long addr, unsigned long pfn, pgprot_t pgprot)
{
	int err = vm_insert_pfn_prot(vma, addr, pfn, pgprot);

	if (unlikely(err == -ENOMEM))
		return VM_FAULT_OOM;
	if (unlikely(err < 0 && err != -EBUSY))
		return VM_FAULT_SIGBUS;

	return VM_FAULT_NOPAGE;
}
#endif

/**
 * struct mgm_group - Structure to keep track of the number of allocated
 *                    pages per group
 *
 * @size:  The number of allocated small(4KB) pages
 * @lp_size:  The number of allocated large(2MB) pages
 * @insert_pfn: The number of calls to map pages for CPU access.
 * @update_gpu_pte: The number of calls to update GPU page table entries.
 * @ptid: The partition ID for this group
 * @pbha: The PBHA bits assigned to this group,
 * @state: The lifecycle state of the partition associated with this group
 * This structure allows page allocation information to be displayed via
 * debugfs. Display is organized per group with small and large sized pages.
 */
struct mgm_group {
	atomic_t size;
	atomic_t lp_size;
	atomic_t insert_pfn;
	atomic_t update_gpu_pte;

	ptid_t ptid;
	ptpbha_t pbha;
	enum {
		MGM_GROUP_STATE_NEW = 0,
		MGM_GROUP_STATE_ENABLED = 10,
		MGM_GROUP_STATE_DISABLED_NOT_FREED = 20,
		MGM_GROUP_STATE_DISABLED = 30,
	} state;
};

/**
 * struct mgm_groups - Structure for groups of memory group manager
 *
 * @groups: To keep track of the number of allocated pages of all groups
 * @dev: device attached
 * @pt_handle: Link to SLC partition data
 * @mgm_debugfs_root: debugfs root directory of memory group manager
 *
 * This structure allows page allocation information to be displayed via
 * debugfs. Display is organized per group with small and large sized pages.
 */
struct mgm_groups {
	struct mgm_group groups[MEMORY_GROUP_MANAGER_NR_GROUPS];
	struct device *dev;
	struct pt_handle *pt_handle;
#ifdef CONFIG_DEBUG_FS
	struct dentry *mgm_debugfs_root;
#endif
};

#ifdef CONFIG_DEBUG_FS

static int mgm_debugfs_state_get(void *data, u64 *val)
{
	struct mgm_group *group = data;
	*val = (int)group->state;
	return 0;
}

static int mgm_debugfs_size_get(void *data, u64 *val)
{
	struct mgm_group *group = data;
	*val = atomic_read(&group->size);
	return 0;
}

static int mgm_debugfs_lp_size_get(void *data, u64 *val)
{
	struct mgm_group *group = data;
	*val = atomic_read(&group->lp_size);
	return 0;
}

static int mgm_debugfs_insert_pfn_get(void *data, u64 *val)
{
	struct mgm_group *group = data;
	*val = atomic_read(&group->insert_pfn);
	return 0;
}

static int mgm_debugfs_update_gpu_pte_get(void *data, u64 *val)
{
	struct mgm_group *group = data;
	*val = atomic_read(&group->update_gpu_pte);
	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(fops_mgm_state, mgm_debugfs_state_get,
	NULL, "%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_mgm_size, mgm_debugfs_size_get,
	NULL, "%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_mgm_lp_size, mgm_debugfs_lp_size_get,
	NULL, "%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_mgm_insert_pfn, mgm_debugfs_insert_pfn_get,
	NULL, "%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_mgm_update_gpu_pte, mgm_debugfs_update_gpu_pte_get,
	NULL, "%llu\n");

static void mgm_debugfs_term(struct mgm_groups *data)
{
	debugfs_remove_recursive(data->mgm_debugfs_root);
}

#define MGM_DEBUGFS_GROUP_NAME_MAX 10
static int mgm_debugfs_init(struct mgm_groups *mgm_data)
{
	int i;
	struct dentry *e, *g;
	char debugfs_group_name[MGM_DEBUGFS_GROUP_NAME_MAX];

	/*
	 * Create root directory of memory-group-manager
	 */
	mgm_data->mgm_debugfs_root =
		debugfs_create_dir("physical-memory-group-manager", NULL);
	if (IS_ERR(mgm_data->mgm_debugfs_root)) {
		dev_err(mgm_data->dev,
			"debugfs: Failed to create root directory\n");
		return -ENODEV;
	}

	/*
	 * Create debugfs files per group
	 */
	for (i = 0; i < MEMORY_GROUP_MANAGER_NR_GROUPS; i++) {
		scnprintf(debugfs_group_name, MGM_DEBUGFS_GROUP_NAME_MAX,
				"group_%02d", i);
		g = debugfs_create_dir(debugfs_group_name,
				mgm_data->mgm_debugfs_root);
		if (IS_ERR(g)) {
			dev_err(mgm_data->dev,
				"debugfs: Couldn't create group[%d]\n", i);
			goto remove_debugfs;
		}

		e = debugfs_create_file("state", 0444, g, &mgm_data->groups[i],
				&fops_mgm_state);
		if (IS_ERR(e)) {
			dev_err(mgm_data->dev,
				"debugfs: Couldn't create state[%d]\n", i);
			goto remove_debugfs;
		}


		e = debugfs_create_file("size", 0444, g, &mgm_data->groups[i],
				&fops_mgm_size);
		if (IS_ERR(e)) {
			dev_err(mgm_data->dev,
				"debugfs: Couldn't create size[%d]\n", i);
			goto remove_debugfs;
		}

		e = debugfs_create_file("lp_size", 0444, g,
				&mgm_data->groups[i], &fops_mgm_lp_size);
		if (IS_ERR(e)) {
			dev_err(mgm_data->dev,
				"debugfs: Couldn't create lp_size[%d]\n", i);
			goto remove_debugfs;
		}

		e = debugfs_create_file("insert_pfn", 0444, g,
				&mgm_data->groups[i], &fops_mgm_insert_pfn);
		if (IS_ERR(e)) {
			dev_err(mgm_data->dev,
				"debugfs: Couldn't create insert_pfn[%d]\n", i);
			goto remove_debugfs;
		}

		e = debugfs_create_file("update_gpu_pte", 0444, g,
				&mgm_data->groups[i], &fops_mgm_update_gpu_pte);
		if (IS_ERR(e)) {
			dev_err(mgm_data->dev,
				"debugfs: Couldn't create update_gpu_pte[%d]\n",
				i);
			goto remove_debugfs;
		}
	}

	return 0;

remove_debugfs:
	mgm_debugfs_term(mgm_data);
	return -ENODEV;
}

#else

static void mgm_debugfs_term(struct mgm_groups *data)
{
}

static int mgm_debugfs_init(struct mgm_groups *mgm_data)
{
	return 0;
}

#endif /* CONFIG_DEBUG_FS */

#define ORDER_SMALL_PAGE 0
#define ORDER_LARGE_PAGE 9
static void update_size(struct memory_group_manager_device *mgm_dev, int
		group_id, int order, bool alloc)
{
	struct mgm_groups *data = mgm_dev->data;

	switch (order) {
	case ORDER_SMALL_PAGE:
		if (alloc)
			atomic_inc(&data->groups[group_id].size);
		else {
			WARN_ON(atomic_read(&data->groups[group_id].size) == 0);
			atomic_dec(&data->groups[group_id].size);
		}
	break;

	case ORDER_LARGE_PAGE:
		if (alloc)
			atomic_inc(&data->groups[group_id].lp_size);
		else {
			WARN_ON(atomic_read(
				&data->groups[group_id].lp_size) == 0);
			atomic_dec(&data->groups[group_id].lp_size);
		}
	break;

	default:
		dev_err(data->dev, "Unknown order(%d)\n", order);
	break;
	}
}

static struct page *mgm_alloc_page(
	struct memory_group_manager_device *mgm_dev, int group_id,
	gfp_t gfp_mask, unsigned int order)
{
	struct mgm_groups *const data = mgm_dev->data;
	struct page *p;

	dev_dbg(data->dev,
		"%s(mgm_dev=%p, group_id=%d gfp_mask=0x%x order=%u\n",
		__func__, (void *)mgm_dev, group_id, gfp_mask, order);

	if (INVALID_GROUP_ID(group_id))
		return NULL;

	/* We don't expect to be allocting pages into the group used for
	 * external or imported memory
	 */
	if (WARN_ON(group_id == MGM_IMPORTED_MEMORY_GROUP_ID))
		return NULL;

	/* If we are allocating a page in this group for the first time then
	 *  ensure that we have enabled the relevant partitions for it.
	 */
	if (group_id != MGM_RESERVED_GROUP_ID) {
		int ptid, pbha;
		switch (data->groups[group_id].state) {
		case MGM_GROUP_STATE_NEW:
			ptid = pt_client_enable(data->pt_handle,
				GROUP_ID_TO_PT_IDX(group_id));
			if (ptid == -EINVAL) {
				dev_err(data->dev,
					"Failed to get partition for group: "
					"%d\n", group_id);
			} else {
				dev_info(data->dev,
					"pt_client_enable returned ptid=%d for"
					" group=%d",
					ptid, group_id);
			}

			pbha = pt_pbha(data->dev->of_node,
				GROUP_ID_TO_PT_IDX(group_id));
			if (pbha == PT_PBHA_INVALID) {
				dev_err(data->dev,
					"Failed to get PBHA for group: %d\n",
					 group_id);
			} else {
				dev_info(data->dev,
					"pt_pbha returned PBHA=%d for group=%d",
					pbha, group_id);
			}

			data->groups[group_id].ptid = ptid;
			data->groups[group_id].pbha = pbha;
			data->groups[group_id].state = MGM_GROUP_STATE_ENABLED;

			break;
		case MGM_GROUP_STATE_ENABLED:
		case MGM_GROUP_STATE_DISABLED_NOT_FREED:
		case MGM_GROUP_STATE_DISABLED:
			/* Everything should already be set up*/
			break;
		default:
			dev_err(data->dev, "Group %d in invalid state %d\n",
				group_id, data->groups[group_id].state);
		}
	}

	p = alloc_pages(gfp_mask, order);

	if (p) {
		update_size(mgm_dev, group_id, order, true);
	} else {
		struct mgm_groups *data = mgm_dev->data;
		dev_err(data->dev, "alloc_pages failed\n");
	}

	return p;
}

static void mgm_free_page(
	struct memory_group_manager_device *mgm_dev, int group_id,
	struct page *page, unsigned int order)
{
	struct mgm_groups *const data = mgm_dev->data;

	dev_dbg(data->dev, "%s(mgm_dev=%p, group_id=%d page=%p order=%u\n",
		__func__, (void *)mgm_dev, group_id, (void *)page, order);

	if (INVALID_GROUP_ID(group_id))
		return;

	__free_pages(page, order);

	/* TODO: Determine the logic of when we disable a partition depending
	 *       on when pages in that group drop to zero? Or after a timeout?
	 */

	update_size(mgm_dev, group_id, order, false);
}

static int mgm_get_import_memory_id(
	struct memory_group_manager_device *mgm_dev,
	struct memory_group_manager_import_data *import_data)
{
	struct mgm_groups *const data = mgm_dev->data;

	dev_dbg(data->dev, "%s(mgm_dev=%p, import_data=%p (type=%d)\n",
		__func__, (void *)mgm_dev, (void *)import_data,
		(int)import_data->type);

	if (!WARN_ON(!import_data)) {
		WARN_ON(!import_data->u.dma_buf);

		WARN_ON(import_data->type !=
				MEMORY_GROUP_MANAGER_IMPORT_TYPE_DMA_BUF);
	}

	return MGM_IMPORTED_MEMORY_GROUP_ID;
}

static u64 mgm_update_gpu_pte(
	struct memory_group_manager_device *const mgm_dev, int const group_id,
	int const mmu_level, u64 pte)
{
	struct mgm_groups *const data = mgm_dev->data;
	unsigned int pbha;

	dev_dbg(data->dev,
		"%s(mgm_dev=%p, group_id=%d, mmu_level=%d, pte=0x%llx)\n",
		__func__, (void *)mgm_dev, group_id, mmu_level, pte);

	if (INVALID_GROUP_ID(group_id))
		return pte;

	/* Clear any bits set in the PBHA range */
	if (pte & ((u64)PBHA_BIT_MASK << PBHA_BIT_POS)) {
		dev_warn(data->dev,
			"%s: updating pte with bits already set in PBHA range",
			__func__);
		pte &= ~((u64)PBHA_BIT_MASK << PBHA_BIT_POS);
	}

	switch (group_id) {
	case MGM_RESERVED_GROUP_ID:
	case  MGM_IMPORTED_MEMORY_GROUP_ID:
		/* The reserved group doesn't set PBHA bits */
		/* TODO: Determine what to do with imported memory */
		break;
	default:
		/* All other groups will have PBHA bits */
		if (data->groups[group_id].state > MGM_GROUP_STATE_NEW) {
			u64 old_pte = pte;
			pbha = data->groups[group_id].pbha;

			pte |= ((u64)pbha & PBHA_BIT_MASK) << PBHA_BIT_POS;

			dev_dbg(data->dev,
				"%s: group_id=%d pbha=%d "
				"pte=0x%llx -> 0x%llx\n",
				__func__, group_id, pbha, old_pte, pte);

		} else {
			dev_err(data->dev,
				"Tried to get PBHA of uninitialized group=%d",
				group_id);
		}
	}

	atomic_inc(&data->groups[group_id].update_gpu_pte);

	return pte;
}

static vm_fault_t mgm_vmf_insert_pfn_prot(
	struct memory_group_manager_device *const mgm_dev, int const group_id,
	struct vm_area_struct *const vma, unsigned long const addr,
	unsigned long const pfn, pgprot_t const prot)
{
	struct mgm_groups *const data = mgm_dev->data;
	vm_fault_t fault;

	dev_dbg(data->dev,
		"%s(mgm_dev=%p, group_id=%d, vma=%p, addr=0x%lx, pfn=0x%lx,"
		" prot=0x%llx)\n",
		__func__, (void *)mgm_dev, group_id, (void *)vma, addr, pfn,
		pgprot_val(prot));

	if (INVALID_GROUP_ID(group_id))
		return VM_FAULT_SIGBUS;

	fault = vmf_insert_pfn_prot(vma, addr, pfn, prot);

	if (fault == VM_FAULT_NOPAGE)
		atomic_inc(&data->groups[group_id].insert_pfn);
	else
		dev_err(data->dev, "vmf_insert_pfn_prot failed\n");

	return fault;
}

static void mgm_resize_callback(void *data, int id, size_t size_allocated)
{
	/* Currently we don't do anything on partition resize */
	struct mgm_groups *const mgm_data = (struct mgm_groups *)data;
	dev_dbg(mgm_data->dev, "Resize callback called, size_allocated: %zu\n",
		size_allocated);
}

static int mgm_initialize_data(struct mgm_groups *mgm_data)
{
	int i, ret;

	for (i = 0; i < MEMORY_GROUP_MANAGER_NR_GROUPS; i++) {
		atomic_set(&mgm_data->groups[i].size, 0);
		atomic_set(&mgm_data->groups[i].lp_size, 0);
		atomic_set(&mgm_data->groups[i].insert_pfn, 0);
		atomic_set(&mgm_data->groups[i].update_gpu_pte, 0);

		mgm_data->groups[i].pbha = MGM_PBHA_DEFAULT;
		mgm_data->groups[i].state = MGM_GROUP_STATE_NEW;
	}

	/*
	 * Initialize SLC partitions. We don't enable partitions until
	 * we actually allocate memory to the corresponding memory
	 * group
	 */
	mgm_data->pt_handle = pt_client_register(
		mgm_data->dev->of_node,
		(void *)mgm_data, &mgm_resize_callback);

	if (IS_ERR(mgm_data->pt_handle)) {
		ret = PTR_ERR(mgm_data->pt_handle);
		dev_err(mgm_data->dev, "pt_client_register returned %d\n", ret);
		return ret;
	}

	/* We don't use PBHA bits for the reserved memory group, and so
	 * it is effectively already initialized.
	 */
	mgm_data->groups[MGM_RESERVED_GROUP_ID].state = MGM_GROUP_STATE_ENABLED;

	ret = mgm_debugfs_init(mgm_data);

	return ret;
}

static void mgm_term_data(struct mgm_groups *data)
{
	int i;
	struct mgm_group *group;

	for (i = 0; i < MEMORY_GROUP_MANAGER_NR_GROUPS; i++) {
		group = &data->groups[i];

		/* Shouldn't have outstanding page allocations at this stage*/
		if (atomic_read(&group->size) != 0)
			dev_warn(data->dev,
				"%zu 0-order pages in group(%d) leaked\n",
				(size_t)atomic_read(&group->size), i);
		if (atomic_read(&group->lp_size) != 0)
			dev_warn(data->dev,
				"%zu 9 order pages in group(%d) leaked\n",
				(size_t)atomic_read(&group->lp_size), i);

		/* Disable partition indices and free the partition */
		switch (group->state) {

		case MGM_GROUP_STATE_NEW:
		case MGM_GROUP_STATE_DISABLED:
			/* Nothing to do */
			break;

		case MGM_GROUP_STATE_ENABLED:
		case MGM_GROUP_STATE_DISABLED_NOT_FREED:
			pt_client_free(data->pt_handle, group->ptid);
			break;

		default:
			dev_err(data->dev, "Group %d in invalid state %d\n",
				i, group->state);
		}
	}

	pt_client_unregister(data->pt_handle);

	mgm_debugfs_term(data);
}

static int memory_group_manager_probe(struct platform_device *pdev)
{
	struct memory_group_manager_device *mgm_dev;
	struct mgm_groups *mgm_data;

	mgm_dev = kzalloc(sizeof(*mgm_dev), GFP_KERNEL);
	if (!mgm_dev)
		return -ENOMEM;

	mgm_dev->owner = THIS_MODULE;
	mgm_dev->ops.mgm_alloc_page = mgm_alloc_page;
	mgm_dev->ops.mgm_free_page = mgm_free_page;
	mgm_dev->ops.mgm_get_import_memory_id =
			mgm_get_import_memory_id;
	mgm_dev->ops.mgm_vmf_insert_pfn_prot = mgm_vmf_insert_pfn_prot;
	mgm_dev->ops.mgm_update_gpu_pte = mgm_update_gpu_pte;

	mgm_data = kzalloc(sizeof(*mgm_data), GFP_KERNEL);
	if (!mgm_data) {
		kfree(mgm_dev);
		return -ENOMEM;
	}

	mgm_dev->data = mgm_data;
	mgm_data->dev = &pdev->dev;

	if (mgm_initialize_data(mgm_data)) {
		kfree(mgm_data);
		kfree(mgm_dev);
		return -ENOENT;
	}

	platform_set_drvdata(pdev, mgm_dev);
	dev_info(&pdev->dev, "Memory group manager probed successfully\n");

	return 0;
}

static int memory_group_manager_remove(struct platform_device *pdev)
{
	struct memory_group_manager_device *mgm_dev =
		platform_get_drvdata(pdev);
	struct mgm_groups *mgm_data = mgm_dev->data;

	mgm_term_data(mgm_data);
	kfree(mgm_data);

	kfree(mgm_dev);

	dev_info(&pdev->dev, "Memory group manager removed successfully\n");

	return 0;
}

static const struct of_device_id memory_group_manager_dt_ids[] = {
	{ .compatible = "arm,physical-memory-group-manager" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, memory_group_manager_dt_ids);

struct platform_driver memory_group_manager_driver = {
	.probe = memory_group_manager_probe,
	.remove = memory_group_manager_remove,
	.driver = {
		.name = "mali-mgm",
		.owner = THIS_MODULE,
		.of_match_table = of_match_ptr(memory_group_manager_dt_ids),
		/*
		 * Prevent the mgm_dev from being unbound and freed, as others
		 * may have pointers to it and would get confused, or crash, if
		 * it suddenly disappeared.
		 */
		.suppress_bind_attrs = true,
	}
};