region.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <commonlib/helpers.h>
#include <commonlib/region.h>
#include <string.h>
 
int region_is_subregion(const struct region *p, const struct region *c)
{
        if (region_offset(c) < region_offset(p))
                return 0;
 
        if (region_end(c) > region_end(p))
                return 0;
 
        if (region_end(c) < region_offset(c))
                return 0;
 
        return 1;
}
 
static int normalize_and_ok(const struct region *outer, struct region *inner)
{
        inner->offset += region_offset(outer);
        return region_is_subregion(outer, inner);
}
 
static const struct region_device *rdev_root(const struct region_device *rdev)
{
        if (rdev->root == NULL)
                return rdev;
        return rdev->root;
}
 
ssize_t rdev_relative_offset(const struct region_device *p,
                                const struct region_device *c)
{
        if (rdev_root(p) != rdev_root(c))
                return -1;
 
        if (!region_is_subregion(&p->region, &c->region))
                return -1;
 
        return region_device_offset(c) - region_device_offset(p);
}
 
void *rdev_mmap(const struct region_device *rd, size_t offset, size_t size)
{
        const struct region_device *rdev;
        struct region req = {
                .offset = offset,
                .size = size,
        };
 
        if (!normalize_and_ok(&rd->region, &req))
                return NULL;
 
        rdev = rdev_root(rd);
 
        if (rdev->ops->mmap == NULL)
                return NULL;
 
        return rdev->ops->mmap(rdev, req.offset, req.size);
}
 
int rdev_munmap(const struct region_device *rd, void *mapping)
{
        const struct region_device *rdev;
 
        rdev = rdev_root(rd);
 
        if (rdev->ops->munmap == NULL)
                return -1;
 
        return rdev->ops->munmap(rdev, mapping);
}
 
ssize_t rdev_readat(const struct region_device *rd, void *b, size_t offset,
                        size_t size)
{
        const struct region_device *rdev;
        struct region req = {
                .offset = offset,
                .size = size,
        };
 
        if (!normalize_and_ok(&rd->region, &req))
                return -1;
 
        rdev = rdev_root(rd);
 
        return rdev->ops->readat(rdev, b, req.offset, req.size);
}
 
ssize_t rdev_writeat(const struct region_device *rd, const void *b,
                        size_t offset, size_t size)
{
        const struct region_device *rdev;
        struct region req = {
                .offset = offset,
                .size = size,
        };
 
        if (!normalize_and_ok(&rd->region, &req))
                return -1;
 
        rdev = rdev_root(rd);
 
        if (rdev->ops->writeat == NULL)
                return -1;
 
        return rdev->ops->writeat(rdev, b, req.offset, req.size);
}
 
ssize_t rdev_eraseat(const struct region_device *rd, size_t offset,
                        size_t size)
{
        const struct region_device *rdev;
        struct region req = {
                .offset = offset,
                .size = size,
        };
 
        if (!normalize_and_ok(&rd->region, &req))
                return -1;
 
        rdev = rdev_root(rd);
 
        /* If the eraseat ptr is NULL we assume that the erase
         * function was completed successfully. */
        if (rdev->ops->eraseat == NULL)
                return size;
 
        return rdev->ops->eraseat(rdev, req.offset, req.size);
}
 
int rdev_chain(struct region_device *child, const struct region_device *parent,
                size_t offset, size_t size)
{
        struct region req = {
                .offset = offset,
                .size = size,
        };
 
        if (!normalize_and_ok(&parent->region, &req))
                return -1;
 
        /* Keep track of root region device. Note the offsets are relative
         * to the root device. */
        child->root = rdev_root(parent);
        child->ops = NULL;
        child->region.offset = req.offset;
        child->region.size = req.size;
 
        return 0;
}
 
static void mem_region_device_init(struct mem_region_device *mdev,
                const struct region_device_ops *ops, void *base, size_t size)
{
        memset(mdev, 0, sizeof(*mdev));
        mdev->base = base;
        mdev->rdev.ops = ops;
        mdev->rdev.region.size = size;
}
 
void mem_region_device_ro_init(struct mem_region_device *mdev, void *base,
                                size_t size)
{
        return mem_region_device_init(mdev, &mem_rdev_ro_ops, base, size);
}
 
void mem_region_device_rw_init(struct mem_region_device *mdev, void *base,
                size_t size)
{
        return mem_region_device_init(mdev, &mem_rdev_rw_ops, base, size);
}
 
void region_device_init(struct region_device *rdev,
                        const struct region_device_ops *ops, size_t offset,
                        size_t size)
{
        memset(rdev, 0, sizeof(*rdev));
        rdev->root = NULL;
        rdev->ops = ops;
        rdev->region.offset = offset;
        rdev->region.size = size;
}
 
static void xlate_region_device_init(struct xlate_region_device *xdev,
                        const struct region_device_ops *ops,
                        size_t window_count, const struct xlate_window *window_arr,
                        size_t parent_size)
{
        memset(xdev, 0, sizeof(*xdev));
        xdev->window_count = window_count;
        xdev->window_arr = window_arr;
        region_device_init(&xdev->rdev, ops, 0, parent_size);
}
 
void xlate_region_device_ro_init(struct xlate_region_device *xdev,
                              size_t window_count, const struct xlate_window *window_arr,
                              size_t parent_size)
{
        xlate_region_device_init(xdev, &xlate_rdev_ro_ops, window_count, window_arr,
                        parent_size);
}
 
void xlate_region_device_rw_init(struct xlate_region_device *xdev,
                              size_t window_count, const struct xlate_window *window_arr,
                              size_t parent_size)
{
        xlate_region_device_init(xdev, &xlate_rdev_rw_ops, window_count, window_arr,
                        parent_size);
}
 
void xlate_window_init(struct xlate_window *window, const struct region_device *access_dev,
                              size_t sub_region_offset, size_t sub_region_size)
{
        window->access_dev = access_dev;
        window->sub_region.offset = sub_region_offset;
        window->sub_region.size = sub_region_size;
}
 
static void *mdev_mmap(const struct region_device *rd, size_t offset,
                        size_t size __unused)
{
        const struct mem_region_device *mdev;
 
        mdev = container_of(rd, __typeof__(*mdev), rdev);
 
        return &mdev->base[offset];
}
 
static int mdev_munmap(const struct region_device *rd __unused,
                        void *mapping __unused)
{
        return 0;
}
 
static ssize_t mdev_readat(const struct region_device *rd, void *b,
                                size_t offset, size_t size)
{
        const struct mem_region_device *mdev;
 
        mdev = container_of(rd, __typeof__(*mdev), rdev);
 
        memcpy(b, &mdev->base[offset], size);
 
        return size;
}
 
static ssize_t mdev_writeat(const struct region_device *rd, const void *b,
                                size_t offset, size_t size)
{
        const struct mem_region_device *mdev;
 
        mdev = container_of(rd, __typeof__(*mdev), rdev);
 
        memcpy(&mdev->base[offset], b, size);
 
        return size;
}
 
static ssize_t mdev_eraseat(const struct region_device *rd, size_t offset,
                                size_t size)
{
        const struct mem_region_device *mdev;
 
        mdev = container_of(rd, __typeof__(*mdev), rdev);
 
        memset(&mdev->base[offset], 0, size);
 
        return size;
}
 
const struct region_device_ops mem_rdev_ro_ops = {
        .mmap = mdev_mmap,
        .munmap = mdev_munmap,
        .readat = mdev_readat,
};
 
const struct region_device_ops mem_rdev_rw_ops = {
        .mmap = mdev_mmap,
        .munmap = mdev_munmap,
        .readat = mdev_readat,
        .writeat = mdev_writeat,
        .eraseat = mdev_eraseat,
};
 
static const struct mem_region_device mem_rdev = MEM_REGION_DEV_RO_INIT(0, ~(size_t)0);
static const struct mem_region_device mem_rdev_rw = MEM_REGION_DEV_RW_INIT(0, ~(size_t)0);
 
int rdev_chain_mem(struct region_device *child, const void *base, size_t size)
{
        return rdev_chain(child, &mem_rdev.rdev, (uintptr_t)base, size);
}
 
int rdev_chain_mem_rw(struct region_device *child, void *base, size_t size)
{
        return rdev_chain(child, &mem_rdev_rw.rdev, (uintptr_t)base, size);
}
 
void *mmap_helper_rdev_mmap(const struct region_device *rd, size_t offset,
                                size_t size)
{
        struct mmap_helper_region_device *mdev;
        void *mapping;
 
        mdev = container_of((void *)rd, __typeof__(*mdev), rdev);
 
        mapping = mem_pool_alloc(mdev->pool, size);
 
        if (mapping == NULL)
                return NULL;
 
        if (rd->ops->readat(rd, mapping, offset, size) != size) {
                mem_pool_free(mdev->pool, mapping);
                return NULL;
        }
 
        return mapping;
}
 
int mmap_helper_rdev_munmap(const struct region_device *rd, void *mapping)
{
        struct mmap_helper_region_device *mdev;
 
        mdev = container_of((void *)rd, __typeof__(*mdev), rdev);
 
        mem_pool_free(mdev->pool, mapping);
 
        return 0;
}
 
static const struct xlate_window *xlate_find_window(const struct xlate_region_device *xldev,
                                                    const struct region *req)
{
        size_t i;
        const struct xlate_window *xlwindow;
 
        for (i = 0; i < xldev->window_count; i++) {
                xlwindow = &xldev->window_arr[i];
                if (region_is_subregion(&xlwindow->sub_region, req))
                        return xlwindow;
        }
 
        return NULL;
}
 
static void *xlate_mmap(const struct region_device *rd, size_t offset,
                        size_t size)
{
        const struct xlate_region_device *xldev;
        struct region req = {
                .offset = offset,
                .size = size,
        };
        const struct xlate_window *xlwindow;
 
        xldev = container_of(rd, __typeof__(*xldev), rdev);
 
        xlwindow = xlate_find_window(xldev, &req);
        if (!xlwindow)
                return NULL;
 
        offset -= region_offset(&xlwindow->sub_region);
 
        return rdev_mmap(xlwindow->access_dev, offset, size);
}
 
static int xlate_munmap(const struct region_device *rd __unused, void *mapping __unused)
{
        /*
         * xlate_region_device does not keep track of the access device that was used to service
         * a mmap request. So, munmap does not do anything. If munmap functionality is required,
         * then xlate_region_device will have to be updated to accept some pre-allocated space
         * from caller to keep track of the mapping requests. Since xlate_region_device is only
         * used for memory mapped boot media on the backend right now, skipping munmap is fine.
         */
        return 0;
}
 
static ssize_t xlate_readat(const struct region_device *rd, void *b,
                                size_t offset, size_t size)
{
        struct region req = {
                .offset = offset,
                .size = size,
        };
        const struct xlate_window *xlwindow;
        const struct xlate_region_device *xldev;
 
        xldev = container_of(rd, __typeof__(*xldev), rdev);
 
        xlwindow = xlate_find_window(xldev, &req);
        if (!xlwindow)
                return -1;
 
        offset -= region_offset(&xlwindow->sub_region);
 
        return rdev_readat(xlwindow->access_dev, b, offset, size);
}
 
static ssize_t xlate_writeat(const struct region_device *rd, const void *b,
                                size_t offset, size_t size)
{
        struct region req = {
                .offset = offset,
                .size = size,
        };
        const struct xlate_window *xlwindow;
        const struct xlate_region_device *xldev;
 
        xldev = container_of(rd, __typeof__(*xldev), rdev);
 
        xlwindow = xlate_find_window(xldev, &req);
        if (!xlwindow)
                return -1;
 
        offset -= region_offset(&xlwindow->sub_region);
 
        return rdev_writeat(xlwindow->access_dev, b, offset, size);
}
 
static ssize_t xlate_eraseat(const struct region_device *rd,
                                size_t offset, size_t size)
{
        struct region req = {
                .offset = offset,
                .size = size,
        };
        const struct xlate_window *xlwindow;
        const struct xlate_region_device *xldev;
 
        xldev = container_of(rd, __typeof__(*xldev), rdev);
 
        xlwindow = xlate_find_window(xldev, &req);
        if (!xlwindow)
                return -1;
 
        offset -= region_offset(&xlwindow->sub_region);
 
        return rdev_eraseat(xlwindow->access_dev, offset, size);
}
 
const struct region_device_ops xlate_rdev_ro_ops = {
        .mmap = xlate_mmap,
        .munmap = xlate_munmap,
        .readat = xlate_readat,
};
 
const struct region_device_ops xlate_rdev_rw_ops = {
        .mmap = xlate_mmap,
        .munmap = xlate_munmap,
        .readat = xlate_readat,
        .writeat = xlate_writeat,
        .eraseat = xlate_eraseat,
};
 
static void *incoherent_mmap(const struct region_device *rd, size_t offset,
                                size_t size)
{
        const struct incoherent_rdev *irdev;
 
        irdev = container_of(rd, const struct incoherent_rdev, rdev);
 
        return rdev_mmap(irdev->read, offset, size);
}
 
static int incoherent_munmap(const struct region_device *rd, void *mapping)
{
        const struct incoherent_rdev *irdev;
 
        irdev = container_of(rd, const struct incoherent_rdev, rdev);
 
        return rdev_munmap(irdev->read, mapping);
}
 
static ssize_t incoherent_readat(const struct region_device *rd, void *b,
                                size_t offset, size_t size)
{
        const struct incoherent_rdev *irdev;
 
        irdev = container_of(rd, const struct incoherent_rdev, rdev);
 
        return rdev_readat(irdev->read, b, offset, size);
}
 
static ssize_t incoherent_writeat(const struct region_device *rd, const void *b,
                        size_t offset, size_t size)
{
        const struct incoherent_rdev *irdev;
 
        irdev = container_of(rd, const struct incoherent_rdev, rdev);
 
        return rdev_writeat(irdev->write, b, offset, size);
}
 
static ssize_t incoherent_eraseat(const struct region_device *rd, size_t offset,
                                size_t size)
{
        const struct incoherent_rdev *irdev;
 
        irdev = container_of(rd, const struct incoherent_rdev, rdev);
 
        return rdev_eraseat(irdev->write, offset, size);
}
 
static const struct region_device_ops incoherent_rdev_ops = {
        .mmap = incoherent_mmap,
        .munmap = incoherent_munmap,
        .readat = incoherent_readat,
        .writeat = incoherent_writeat,
        .eraseat = incoherent_eraseat,
};
 
const struct region_device *incoherent_rdev_init(struct incoherent_rdev *irdev,
                                const struct region *r,
                                const struct region_device *read,
                                const struct region_device *write)
{
        const size_t size = region_sz(r);
 
        if (size != region_device_sz(read) || size != region_device_sz(write))
                return NULL;
 
        /* The region is represented as offset 0 to size. That way, the generic
         * rdev operations can be called on the read or write implementation
         * without any unnecessary translation because the offsets all start
         * at 0. */
        region_device_init(&irdev->rdev, &incoherent_rdev_ops, 0, size);
        irdev->read = read;
        irdev->write = write;
 
        return &irdev->rdev;
}